diff --git a/bin/sh/histedit.c b/bin/sh/histedit.c index cf6bebad4c1a..2001b80bd8ed 100644 --- a/bin/sh/histedit.c +++ b/bin/sh/histedit.c @@ -1,699 +1,762 @@ /*- * Copyright (c) 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint #if 0 static char sccsid[] = "@(#)histedit.c 8.2 (Berkeley) 5/4/95"; #endif #endif /* not lint */ #include __FBSDID("$FreeBSD$"); #include #include #include +#include +#include #include #include #include #include #include #include /* * Editline and history functions (and glue). */ #include "shell.h" #include "parser.h" #include "var.h" #include "options.h" #include "main.h" #include "output.h" #include "mystring.h" #include "builtins.h" #ifndef NO_HISTORY #include "myhistedit.h" #include "error.h" #include "eval.h" #include "memalloc.h" #define MAXHISTLOOPS 4 /* max recursions through fc */ #define DEFEDITOR "ed" /* default editor *should* be $EDITOR */ History *hist; /* history cookie */ EditLine *el; /* editline cookie */ int displayhist; +static int savehist; static FILE *el_in, *el_out; static bool in_command_completion; static char *fc_replace(const char *, char *, char *); static int not_fcnumber(const char *); static int str_to_event(const char *, int); static int comparator(const void *, const void *, void *); static char **sh_matches(const char *, int, int); static const char *append_char_function(const char *); static unsigned char sh_complete(EditLine *, int); +static const char * +get_histfile(void) +{ + const char *histfile; + + /* don't try to save if the history size is 0 */ + if (hist == NULL || histsizeval() == 0) + return (NULL); + histfile = expandstr("${HISTFILE-${HOME-}/.sh_history}"); + + if (histfile[0] == '\0') + return (NULL); + return (histfile); +} + +void +histsave(void) +{ + HistEvent he; + char *histtmpname = NULL; + const char *histfile; + int fd; + FILE *f; + + if (!savehist || (histfile = get_histfile()) == NULL) + return; + INTOFF; + asprintf(&histtmpname, "%s.XXXXXXXXXX", histfile); + if (histtmpname == NULL) { + INTON; + return; + } + fd = mkstemp(histtmpname); + if (fd == -1 || (f = fdopen(fd, "w")) == NULL) { + free(histtmpname); + INTON; + return; + } + if (history(hist, &he, H_SAVE_FP, f) < 1 || + rename(histtmpname, histfile) == -1) + unlink(histtmpname); + fclose(f); + free(histtmpname); + INTON; + +} + +void +histload(void) +{ + const char *histfile; + HistEvent he; + + if ((histfile = get_histfile()) == NULL) + return; + errno = 0; + if (history(hist, &he, H_LOAD, histfile) != -1 || errno == ENOENT) + savehist = 1; +} + /* * Set history and editing status. Called whenever the status may * have changed (figures out what to do). */ void histedit(void) { #define editing (Eflag || Vflag) if (iflag) { if (!hist) { /* * turn history on */ INTOFF; hist = history_init(); INTON; if (hist != NULL) sethistsize(histsizeval()); else out2fmt_flush("sh: can't initialize history\n"); } if (editing && !el && isatty(0)) { /* && isatty(2) ??? */ /* * turn editing on */ char *term; INTOFF; if (el_in == NULL) el_in = fdopen(0, "r"); if (el_out == NULL) el_out = fdopen(2, "w"); if (el_in == NULL || el_out == NULL) goto bad; term = lookupvar("TERM"); if (term) setenv("TERM", term, 1); else unsetenv("TERM"); el = el_init(arg0, el_in, el_out, el_out); if (el != NULL) { if (hist) el_set(el, EL_HIST, history, hist); el_set(el, EL_PROMPT, getprompt); el_set(el, EL_ADDFN, "sh-complete", "Filename completion", sh_complete); } else { bad: out2fmt_flush("sh: can't initialize editing\n"); } INTON; } else if (!editing && el) { INTOFF; el_end(el); el = NULL; INTON; } if (el) { if (Vflag) el_set(el, EL_EDITOR, "vi"); else if (Eflag) { el_set(el, EL_EDITOR, "emacs"); el_set(el, EL_BIND, "^R", "em-inc-search-prev", NULL); } el_set(el, EL_BIND, "^I", "sh-complete", NULL); el_source(el, NULL); } } else { INTOFF; if (el) { /* no editing if not interactive */ el_end(el); el = NULL; } if (hist) { history_end(hist); hist = NULL; } INTON; } } void sethistsize(const char *hs) { int histsize; HistEvent he; if (hist != NULL) { if (hs == NULL || !is_number(hs)) histsize = 100; else histsize = atoi(hs); history(hist, &he, H_SETSIZE, histsize); history(hist, &he, H_SETUNIQUE, 1); } } void setterm(const char *term) { if (rootshell && el != NULL && term != NULL) el_set(el, EL_TERMINAL, term); } int histcmd(int argc, char **argv __unused) { int ch; const char *editor = NULL; HistEvent he; int lflg = 0, nflg = 0, rflg = 0, sflg = 0; int i, retval; const char *firststr, *laststr; int first, last, direction; char *pat = NULL, *repl = NULL; static int active = 0; struct jmploc jmploc; struct jmploc *savehandler; char editfilestr[PATH_MAX]; char *volatile editfile; FILE *efp = NULL; int oldhistnum; if (hist == NULL) error("history not active"); if (argc == 1) error("missing history argument"); while (not_fcnumber(*argptr) && (ch = nextopt("e:lnrs")) != '\0') switch ((char)ch) { case 'e': editor = shoptarg; break; case 'l': lflg = 1; break; case 'n': nflg = 1; break; case 'r': rflg = 1; break; case 's': sflg = 1; break; } savehandler = handler; /* * If executing... */ if (lflg == 0 || editor || sflg) { lflg = 0; /* ignore */ editfile = NULL; /* * Catch interrupts to reset active counter and * cleanup temp files. */ if (setjmp(jmploc.loc)) { active = 0; if (editfile) unlink(editfile); handler = savehandler; longjmp(handler->loc, 1); } handler = &jmploc; if (++active > MAXHISTLOOPS) { active = 0; displayhist = 0; error("called recursively too many times"); } /* * Set editor. */ if (sflg == 0) { if (editor == NULL && (editor = bltinlookup("FCEDIT", 1)) == NULL && (editor = bltinlookup("EDITOR", 1)) == NULL) editor = DEFEDITOR; if (editor[0] == '-' && editor[1] == '\0') { sflg = 1; /* no edit */ editor = NULL; } } } /* * If executing, parse [old=new] now */ if (lflg == 0 && *argptr != NULL && ((repl = strchr(*argptr, '=')) != NULL)) { pat = *argptr; *repl++ = '\0'; argptr++; } /* * determine [first] and [last] */ if (*argptr == NULL) { firststr = lflg ? "-16" : "-1"; laststr = "-1"; } else if (argptr[1] == NULL) { firststr = argptr[0]; laststr = lflg ? "-1" : argptr[0]; } else if (argptr[2] == NULL) { firststr = argptr[0]; laststr = argptr[1]; } else error("too many arguments"); /* * Turn into event numbers. */ first = str_to_event(firststr, 0); last = str_to_event(laststr, 1); if (rflg) { i = last; last = first; first = i; } /* * XXX - this should not depend on the event numbers * always increasing. Add sequence numbers or offset * to the history element in next (diskbased) release. */ direction = first < last ? H_PREV : H_NEXT; /* * If editing, grab a temp file. */ if (editor) { int fd; INTOFF; /* easier */ sprintf(editfilestr, "%s/_shXXXXXX", _PATH_TMP); if ((fd = mkstemp(editfilestr)) < 0) error("can't create temporary file %s", editfile); editfile = editfilestr; if ((efp = fdopen(fd, "w")) == NULL) { close(fd); error("Out of space"); } } /* * Loop through selected history events. If listing or executing, * do it now. Otherwise, put into temp file and call the editor * after. * * The history interface needs rethinking, as the following * convolutions will demonstrate. */ history(hist, &he, H_FIRST); retval = history(hist, &he, H_NEXT_EVENT, first); for (;retval != -1; retval = history(hist, &he, direction)) { if (lflg) { if (!nflg) out1fmt("%5d ", he.num); out1str(he.str); } else { const char *s = pat ? fc_replace(he.str, pat, repl) : he.str; if (sflg) { if (displayhist) { out2str(s); flushout(out2); } evalstring(s, 0); if (displayhist && hist) { /* * XXX what about recursive and * relative histnums. */ oldhistnum = he.num; history(hist, &he, H_ENTER, s); /* * XXX H_ENTER moves the internal * cursor, set it back to the current * entry. */ history(hist, &he, H_NEXT_EVENT, oldhistnum); } } else fputs(s, efp); } /* * At end? (if we were to lose last, we'd sure be * messed up). */ if (he.num == last) break; } if (editor) { char *editcmd; fclose(efp); INTON; editcmd = stalloc(strlen(editor) + strlen(editfile) + 2); sprintf(editcmd, "%s %s", editor, editfile); evalstring(editcmd, 0); /* XXX - should use no JC command */ readcmdfile(editfile); /* XXX - should read back - quick tst */ unlink(editfile); } if (lflg == 0 && active > 0) --active; if (displayhist) displayhist = 0; handler = savehandler; return 0; } static char * fc_replace(const char *s, char *p, char *r) { char *dest; int plen = strlen(p); STARTSTACKSTR(dest); while (*s) { if (*s == *p && strncmp(s, p, plen) == 0) { STPUTS(r, dest); s += plen; *p = '\0'; /* so no more matches */ } else STPUTC(*s++, dest); } STPUTC('\0', dest); dest = grabstackstr(dest); return (dest); } static int not_fcnumber(const char *s) { if (s == NULL) return (0); if (*s == '-') s++; return (!is_number(s)); } static int str_to_event(const char *str, int last) { HistEvent he; const char *s = str; int relative = 0; int i, retval; retval = history(hist, &he, H_FIRST); switch (*s) { case '-': relative = 1; /*FALLTHROUGH*/ case '+': s++; } if (is_number(s)) { i = atoi(s); if (relative) { while (retval != -1 && i--) { retval = history(hist, &he, H_NEXT); } if (retval == -1) retval = history(hist, &he, H_LAST); } else { retval = history(hist, &he, H_NEXT_EVENT, i); if (retval == -1) { /* * the notion of first and last is * backwards to that of the history package */ retval = history(hist, &he, last ? H_FIRST : H_LAST); } } if (retval == -1) error("history number %s not found (internal error)", str); } else { /* * pattern */ retval = history(hist, &he, H_PREV_STR, str); if (retval == -1) error("history pattern not found: %s", str); } return (he.num); } int bindcmd(int argc, char **argv) { int ret; FILE *old; FILE *out; if (el == NULL) error("line editing is disabled"); INTOFF; out = out1fp(); if (out == NULL) error("Out of space"); el_get(el, EL_GETFP, 1, &old); el_set(el, EL_SETFP, 1, out); ret = el_parse(el, argc, __DECONST(const char **, argv)); el_set(el, EL_SETFP, 1, old); fclose(out); if (argc > 1 && argv[1][0] == '-' && memchr("ve", argv[1][1], 2) != NULL) { Vflag = argv[1][1] == 'v'; Eflag = !Vflag; histedit(); } INTON; return ret; } /* * Comparator function for qsort(). The use of curpos here is to skip * characters that we already know to compare equal (common prefix). */ static int comparator(const void *a, const void *b, void *thunk) { size_t curpos = (intptr_t)thunk; return (strcmp(*(char *const *)a + curpos, *(char *const *)b + curpos)); } /* * This function is passed to libedit's fn_complete2(). The library will * use it instead of its standard function that finds matching files in * current directory. If we're at the start of the line, we want to look * for available commands from all paths in $PATH. */ static char **sh_matches(const char *text, int start, int end) { char *free_path = NULL, *path; const char *dirname; char **matches = NULL; size_t i = 0, size = 16, uniq; size_t curpos = end - start, lcstring = -1; in_command_completion = false; if (start > 0 || memchr("/.~", text[0], 3) != NULL) return (NULL); in_command_completion = true; if ((free_path = path = strdup(pathval())) == NULL) goto out; if ((matches = malloc(size * sizeof(matches[0]))) == NULL) goto out; while ((dirname = strsep(&path, ":")) != NULL) { struct dirent *entry; DIR *dir; int dfd; dir = opendir(dirname[0] == '\0' ? "." : dirname); if (dir == NULL) continue; if ((dfd = dirfd(dir)) == -1) { closedir(dir); continue; } while ((entry = readdir(dir)) != NULL) { struct stat statb; char **rmatches; if (strncmp(entry->d_name, text, curpos) != 0) continue; if (entry->d_type == DT_UNKNOWN || entry->d_type == DT_LNK) { if (fstatat(dfd, entry->d_name, &statb, 0) == -1) continue; if (!S_ISREG(statb.st_mode)) continue; } else if (entry->d_type != DT_REG) continue; matches[++i] = strdup(entry->d_name); if (i < size - 1) continue; size *= 2; rmatches = reallocarray(matches, size, sizeof(matches[0])); if (rmatches == NULL) { closedir(dir); goto out; } matches = rmatches; } closedir(dir); } out: free(free_path); if (i == 0) { free(matches); return (NULL); } uniq = 1; if (i > 1) { qsort_s(matches + 1, i, sizeof(matches[0]), comparator, (void *)(intptr_t)curpos); for (size_t k = 2; k <= i; k++) { const char *l = matches[uniq] + curpos; const char *r = matches[k] + curpos; size_t common = 0; while (*l != '\0' && *r != '\0' && *l == *r) (void)l++, r++, common++; if (common < lcstring) lcstring = common; if (*l == *r) free(matches[k]); else matches[++uniq] = matches[k]; } } matches[uniq + 1] = NULL; /* * matches[0] is special: it's not a real matching file name but a common * prefix for all matching names. It can't be null, unlike any other * element of the array. When strings matches[0] and matches[1] compare * equal and matches[2] is null that means to libedit that there is only * a single match. It will then replace user input with possibly escaped * string in matches[0] which is the reason to copy the full name of the * only match. */ if (uniq == 1) matches[0] = strdup(matches[1]); else if (lcstring != (size_t)-1) matches[0] = strndup(matches[1], curpos + lcstring); else matches[0] = strdup(text); if (matches[0] == NULL) { for (size_t k = 1; k <= uniq; k++) free(matches[k]); free(matches); return (NULL); } return (matches); } /* * If we don't specify this function as app_func in the call to fn_complete2, * libedit will use the default one, which adds a " " to plain files and * a "/" to directories regardless of whether it's a command name or a plain * path (relative or absolute). We never want to add "/" to commands. * * For example, after I did "mkdir rmdir", "rmdi" would be autocompleted to * "rmdir/" instead of "rmdir ". */ static const char * append_char_function(const char *name) { struct stat stbuf; char *expname = name[0] == '~' ? fn_tilde_expand(name) : NULL; const char *rs; if (!in_command_completion && stat(expname ? expname : name, &stbuf) == 0 && S_ISDIR(stbuf.st_mode)) rs = "/"; else rs = " "; free(expname); return (rs); } /* * This is passed to el_set(el, EL_ADDFN, ...) so that it's possible to * bind a key (tab by default) to execute the function. */ unsigned char sh_complete(EditLine *sel, int ch __unused) { return (unsigned char)fn_complete2(sel, NULL, sh_matches, L" \t\n\"\\'`@$><=;|&{(", NULL, append_char_function, (size_t)100, NULL, &((int) {0}), NULL, NULL, FN_QUOTE_MATCH); } #else #include "error.h" int histcmd(int argc __unused, char **argv __unused) { error("not compiled with history support"); /*NOTREACHED*/ return (0); } int bindcmd(int argc __unused, char **argv __unused) { error("not compiled with line editing support"); return (0); } #endif diff --git a/bin/sh/main.c b/bin/sh/main.c index cbe026e13640..b0a5fac6fd4e 100644 --- a/bin/sh/main.c +++ b/bin/sh/main.c @@ -1,344 +1,351 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint static char const copyright[] = "@(#) Copyright (c) 1991, 1993\n\ The Regents of the University of California. All rights reserved.\n"; #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)main.c 8.6 (Berkeley) 5/28/95"; #endif #endif /* not lint */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include "shell.h" #include "main.h" #include "mail.h" #include "options.h" #include "output.h" #include "parser.h" #include "nodes.h" #include "expand.h" #include "eval.h" #include "jobs.h" #include "input.h" #include "trap.h" #include "var.h" #include "show.h" #include "memalloc.h" #include "error.h" #include "mystring.h" #include "exec.h" #include "cd.h" #include "redir.h" #include "builtins.h" +#ifndef NO_HISTORY +#include "myhistedit.h" +#endif int rootpid; int rootshell; struct jmploc main_handler; int localeisutf8, initial_localeisutf8; static void reset(void); static void cmdloop(int); static void read_profile(const char *); static char *find_dot_file(char *); /* * Main routine. We initialize things, parse the arguments, execute * profiles if we're a login shell, and then call cmdloop to execute * commands. The setjmp call sets up the location to jump to when an * exception occurs. When an exception occurs the variable "state" * is used to figure out how far we had gotten. */ int main(int argc, char *argv[]) { struct stackmark smark, smark2; volatile int state; char *shinit; (void) setlocale(LC_ALL, ""); initcharset(); state = 0; if (setjmp(main_handler.loc)) { if (state == 0 || iflag == 0 || ! rootshell || exception == EXEXIT) exitshell(exitstatus); reset(); if (exception == EXINT) out2fmt_flush("\n"); popstackmark(&smark); FORCEINTON; /* enable interrupts */ if (state == 1) goto state1; else if (state == 2) goto state2; else if (state == 3) goto state3; else goto state4; } handler = &main_handler; #ifdef DEBUG opentrace(); trputs("Shell args: "); trargs(argv); #endif rootpid = getpid(); rootshell = 1; INTOFF; initvar(); setstackmark(&smark); setstackmark(&smark2); procargs(argc, argv); trap_init(); pwd_init(iflag); INTON; if (iflag) chkmail(1); if (argv[0] && argv[0][0] == '-') { state = 1; read_profile("/etc/profile"); state1: state = 2; if (privileged == 0) read_profile("${HOME-}/.profile"); else read_profile("/etc/suid_profile"); } state2: state = 3; if (!privileged && iflag) { if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') { state = 3; read_profile(shinit); } } +#ifndef NO_HISTORY + if (iflag) + histload(); +#endif state3: state = 4; popstackmark(&smark2); if (minusc) { evalstring(minusc, sflag ? 0 : EV_EXIT); } state4: if (sflag || minusc == NULL) { cmdloop(1); } exitshell(exitstatus); /*NOTREACHED*/ return 0; } static void reset(void) { reseteval(); resetinput(); } /* * Read and execute commands. "Top" is nonzero for the top level command * loop; it turns on prompting if the shell is interactive. */ static void cmdloop(int top) { union node *n; struct stackmark smark; int inter; int numeof = 0; TRACE(("cmdloop(%d) called\n", top)); setstackmark(&smark); for (;;) { if (pendingsig) dotrap(); inter = 0; if (iflag && top) { inter++; showjobs(1, SHOWJOBS_DEFAULT); chkmail(0); flushout(&output); } n = parsecmd(inter); /* showtree(n); DEBUG */ if (n == NEOF) { if (!top || numeof >= 50) break; if (!stoppedjobs()) { if (!Iflag) break; out2fmt_flush("\nUse \"exit\" to leave shell.\n"); } numeof++; } else if (n != NULL && nflag == 0) { job_warning = (job_warning == 2) ? 1 : 0; numeof = 0; evaltree(n, 0); } popstackmark(&smark); setstackmark(&smark); if (evalskip != 0) { if (evalskip == SKIPRETURN) evalskip = 0; break; } } popstackmark(&smark); if (top && iflag) { out2c('\n'); flushout(out2); } } /* * Read /etc/profile or .profile. Return on error. */ static void read_profile(const char *name) { int fd; const char *expandedname; expandedname = expandstr(name); if (expandedname == NULL) return; INTOFF; if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC)) >= 0) setinputfd(fd, 1); INTON; if (fd < 0) return; cmdloop(0); popfile(); } /* * Read a file containing shell functions. */ void readcmdfile(const char *name) { setinputfile(name, 1); cmdloop(0); popfile(); } /* * Take commands from a file. To be compatible we should do a path * search for the file, which is necessary to find sub-commands. */ static char * find_dot_file(char *basename) { char *fullname; const char *opt; const char *path = pathval(); struct stat statb; /* don't try this for absolute or relative paths */ if( strchr(basename, '/')) return basename; while ((fullname = padvance(&path, &opt, basename)) != NULL) { if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) { /* * Don't bother freeing here, since it will * be freed by the caller. */ return fullname; } stunalloc(fullname); } return basename; } int dotcmd(int argc, char **argv) { char *filename, *fullname; if (argc < 2) error("missing filename"); exitstatus = 0; /* * Because we have historically not supported any options, * only treat "--" specially. */ filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1]; fullname = find_dot_file(filename); setinputfile(fullname, 1); commandname = fullname; cmdloop(0); popfile(); return exitstatus; } int exitcmd(int argc, char **argv) { if (stoppedjobs()) return 0; if (argc > 1) exitshell(number(argv[1])); else exitshell_savedstatus(); } diff --git a/bin/sh/myhistedit.h b/bin/sh/myhistedit.h index 968d23c9c1f8..1f513f0ae206 100644 --- a/bin/sh/myhistedit.h +++ b/bin/sh/myhistedit.h @@ -1,46 +1,47 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)myhistedit.h 8.2 (Berkeley) 5/4/95 * $FreeBSD$ */ #include extern History *hist; extern EditLine *el; extern int displayhist; #include void histedit(void); void sethistsize(const char *); void setterm(const char *); - +void histload(void); +void histsave(void); diff --git a/bin/sh/sh.1 b/bin/sh/sh.1 index 76335cfaa2cd..ca3faeff13af 100644 --- a/bin/sh/sh.1 +++ b/bin/sh/sh.1 @@ -1,2896 +1,2905 @@ .\"- .\" Copyright (c) 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" Kenneth Almquist. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" from: @(#)sh.1 8.6 (Berkeley) 5/4/95 .\" $FreeBSD$ .\" -.Dd July 6, 2020 +.Dd May 10, 2021 .Dt SH 1 .Os .Sh NAME .Nm sh .Nd command interpreter (shell) .Sh SYNOPSIS .Nm .Op Fl /+abCEefhIimnPpTuVvx .Op Fl /+o Ar longname .Oo .Ar script .Op Ar arg ... .Oc .Nm .Op Fl /+abCEefhIimnPpTuVvx .Op Fl /+o Ar longname .Fl c Ar string .Oo .Ar name .Op Ar arg ... .Oc .Nm .Op Fl /+abCEefhIimnPpTuVvx .Op Fl /+o Ar longname .Fl s .Op Ar arg ... .Sh DESCRIPTION The .Nm utility is the standard command interpreter for the system. The current version of .Nm is close to the .St -p1003.1 specification for the shell. It only supports features designated by POSIX, plus a few Berkeley extensions. This man page is not intended to be a tutorial nor a complete specification of the shell. .Ss Overview The shell is a command that reads lines from either a file or the terminal, interprets them, and generally executes other commands. It is the program that is started when a user logs into the system, although a user can select a different shell with the .Xr chsh 1 command. The shell implements a language that has flow control constructs, a macro facility that provides a variety of features in addition to data storage, along with built-in history and line editing capabilities. It incorporates many features to aid interactive use and has the advantage that the interpretative language is common to both interactive and non-interactive use (shell scripts). That is, commands can be typed directly to the running shell or can be put into a file, which can be executed directly by the shell. .Ss Invocation .\" .\" XXX This next sentence is incredibly confusing. .\" If no arguments are present and if the standard input of the shell is connected to a terminal (or if the .Fl i option is set), the shell is considered an interactive shell. An interactive shell generally prompts before each command and handles programming and command errors differently (as described below). When first starting, the shell inspects argument 0, and if it begins with a dash .Pq Ql - , the shell is also considered a login shell. This is normally done automatically by the system when the user first logs in. A login shell first reads commands from the files .Pa /etc/profile and then .Pa .profile in a user's home directory, if they exist. If the environment variable .Ev ENV is set on entry to a shell, or is set in the .Pa .profile of a login shell, the shell then subjects its value to parameter expansion and arithmetic expansion and reads commands from the named file. Therefore, a user should place commands that are to be executed only at login time in the .Pa .profile file, and commands that are executed for every shell inside the .Ev ENV file. The user can set the .Ev ENV variable to some file by placing the following line in the file .Pa .profile in the home directory, substituting for .Pa .shrc the filename desired: .Pp .Dl "ENV=$HOME/.shrc; export ENV" .Pp The first non-option argument specified on the command line will be treated as the name of a file from which to read commands (a shell script), and the remaining arguments are set as the positional parameters of the shell .Li ( $1 , $2 , etc.). Otherwise, the shell reads commands from its standard input. .Pp Unlike older versions of .Nm the .Ev ENV script is only sourced on invocation of interactive shells. This closes a well-known, and sometimes easily exploitable security hole related to poorly thought out .Ev ENV scripts. .Ss Argument List Processing All of the single letter options to .Nm have a corresponding long name, with the exception of .Fl c and .Fl /+o . These long names are provided next to the single letter options in the descriptions below. The long name for an option may be specified as an argument to the .Fl /+o option of .Nm . Once the shell is running, the long name for an option may be specified as an argument to the .Fl /+o option of the .Ic set built-in command (described later in the section called .Sx Built-in Commands ) . Introducing an option with a dash .Pq Ql - enables the option, while using a plus .Pq Ql + disables the option. A .Dq Li -- or plain .Ql - will stop option processing and will force the remaining words on the command line to be treated as arguments. The .Fl /+o and .Fl c options do not have long names. They take arguments and are described after the single letter options. .Bl -tag -width indent .It Fl a Li allexport Flag variables for export when assignments are made to them. .It Fl b Li notify Enable asynchronous notification of background job completion. (UNIMPLEMENTED) .It Fl C Li noclobber Do not overwrite existing files with .Ql > . .It Fl E Li emacs Enable the built-in .Xr emacs 1 command line editor (disables the .Fl V option if it has been set; set automatically when interactive on terminals). .It Fl e Li errexit Exit immediately if any untested command fails in non-interactive mode. The exit status of a command is considered to be explicitly tested if the command is part of the list used to control an .Ic if , elif , while , or .Ic until ; if the command is the left hand operand of an .Dq Li && or .Dq Li || operator; or if the command is a pipeline preceded by the .Ic !\& keyword. If a shell function is executed and its exit status is explicitly tested, all commands of the function are considered to be tested as well. .Pp It is recommended to check for failures explicitly instead of relying on .Fl e because it tends to behave in unexpected ways, particularly in larger scripts. .It Fl f Li noglob Disable pathname expansion. .It Fl h Li trackall A do-nothing option for POSIX compliance. .It Fl I Li ignoreeof Ignore .Dv EOF Ap s from input when in interactive mode. .It Fl i Li interactive Force the shell to behave interactively. .It Fl m Li monitor Turn on job control (set automatically when interactive). A new process group is created for each pipeline (called a job). It is possible to suspend jobs or to have them run in the foreground or in the background. In a non-interactive shell, this option can be set even if no terminal is available and is useful to place processes in separate process groups. .It Fl n Li noexec If not interactive, read commands but do not execute them. This is useful for checking the syntax of shell scripts. .It Fl P Li physical Change the default for the .Ic cd and .Ic pwd commands from .Fl L (logical directory layout) to .Fl P (physical directory layout). .It Fl p Li privileged Turn on privileged mode. This mode is enabled on startup if either the effective user or group ID is not equal to the real user or group ID. Turning this mode off sets the effective user and group IDs to the real user and group IDs. When this mode is enabled for interactive shells, the file .Pa /etc/suid_profile is sourced instead of .Pa ~/.profile after .Pa /etc/profile is sourced, and the contents of the .Ev ENV variable are ignored. .It Fl s Li stdin Read commands from standard input (set automatically if no file arguments are present). This option has no effect when set after the shell has already started running (i.e., when set with the .Ic set command). .It Fl T Li trapsasync When waiting for a child, execute traps immediately. If this option is not set, traps are executed after the child exits, as specified in .St -p1003.2 . This nonstandard option is useful for putting guarding shells around children that block signals. The surrounding shell may kill the child or it may just return control to the tty and leave the child alone, like this: .Bd -literal -offset indent sh -T -c "trap 'exit 1' 2 ; some-blocking-program" .Ed .It Fl u Li nounset Write a message to standard error when attempting to expand a variable, a positional parameter or the special parameter .Va \&! that is not set, and if the shell is not interactive, exit immediately. .It Fl V Li vi Enable the built-in .Xr vi 1 command line editor (disables .Fl E if it has been set). .It Fl v Li verbose The shell writes its input to standard error as it is read. Useful for debugging. .It Fl x Li xtrace Write each command (preceded by the value of the .Va PS4 variable subjected to parameter expansion and arithmetic expansion) to standard error before it is executed. Useful for debugging. .It Li nolog Another do-nothing option for POSIX compliance. It only has a long name. .It Li pipefail Change the exit status of a pipeline to the last non-zero exit status of any command in the pipeline, if any. Since an exit due to .Dv SIGPIPE counts as a non-zero exit status, this option may cause non-zero exit status for successful pipelines if a command such as .Xr head 1 in the pipeline terminates with status 0 without reading its input completely. This option only has a long name. .El .Pp The .Fl c option causes the commands to be read from the .Ar string operand instead of from the standard input. Keep in mind that this option only accepts a single string as its argument, hence multi-word strings must be quoted. .Pp The .Fl /+o option takes as its only argument the long name of an option to be enabled or disabled. For example, the following two invocations of .Nm both enable the built-in .Xr emacs 1 command line editor: .Bd -literal -offset indent set -E set -o emacs .Ed .Pp If used without an argument, the .Fl o option displays the current option settings in a human-readable format. If .Cm +o is used without an argument, the current option settings are output in a format suitable for re-input into the shell. .Ss Lexical Structure The shell reads input in terms of lines from a file and breaks it up into words at whitespace (blanks and tabs), and at certain sequences of characters called .Dq operators , which are special to the shell. There are two types of operators: control operators and redirection operators (their meaning is discussed later). The following is a list of valid operators: .Bl -tag -width indent .It Control operators: .Bl -column "XXX" "XXX" "XXX" "XXX" "XXX" -offset center -compact .It Li & Ta Li && Ta Li \&( Ta Li \&) Ta Li \en .It Li ;; Ta Li ;& Ta Li \&; Ta Li \&| Ta Li || .El .It Redirection operators: .Bl -column "XXX" "XXX" "XXX" "XXX" "XXX" -offset center -compact .It Li < Ta Li > Ta Li << Ta Li >> Ta Li <> .It Li <& Ta Li >& Ta Li <<- Ta Li >| Ta \& .El .El .Pp The character .Ql # introduces a comment if used at the beginning of a word. The word starting with .Ql # and the rest of the line are ignored. .Pp ASCII .Dv NUL characters (character code 0) are not allowed in shell input. .Ss Quoting Quoting is used to remove the special meaning of certain characters or words to the shell, such as operators, whitespace, keywords, or alias names. .Pp There are four types of quoting: matched single quotes, dollar-single quotes, matched double quotes, and backslash. .Bl -tag -width indent .It Single Quotes Enclosing characters in single quotes preserves the literal meaning of all the characters (except single quotes, making it impossible to put single-quotes in a single-quoted string). .It Dollar-Single Quotes Enclosing characters between .Li $' and .Li ' preserves the literal meaning of all characters except backslashes and single quotes. A backslash introduces a C-style escape sequence: .Bl -tag -width xUnnnnnnnn .It \ea Alert (ring the terminal bell) .It \eb Backspace .It \ec Ns Ar c The control character denoted by .Li ^ Ns Ar c in .Xr stty 1 . If .Ar c is a backslash, it must be doubled. .It \ee The ESC character (ASCII 0x1b) .It \ef Formfeed .It \en Newline .It \er Carriage return .It \et Horizontal tab .It \ev Vertical tab .It \e\e Literal backslash .It \e\&' Literal single-quote .It \e\&" Literal double-quote .It \e Ns Ar nnn The byte whose octal value is .Ar nnn (one to three digits) .It \ex Ns Ar nn The byte whose hexadecimal value is .Ar nn (one or more digits only the last two of which are used) .It \eu Ns Ar nnnn The Unicode code point .Ar nnnn (four hexadecimal digits) .It \eU Ns Ar nnnnnnnn The Unicode code point .Ar nnnnnnnn (eight hexadecimal digits) .El .Pp The sequences for Unicode code points are currently only useful with UTF-8 locales. They reject code point 0 and UTF-16 surrogates. .Pp If an escape sequence would produce a byte with value 0, that byte and the rest of the string until the matching single-quote are ignored. .Pp Any other string starting with a backslash is an error. .It Double Quotes Enclosing characters within double quotes preserves the literal meaning of all characters except dollar sign .Pq Ql $ , backquote .Pq Ql ` , and backslash .Pq Ql \e . The backslash inside double quotes is historically weird. It remains literal unless it precedes the following characters, which it serves to quote: .Pp .Bl -column "XXX" "XXX" "XXX" "XXX" "XXX" -offset center -compact .It Li $ Ta Li ` Ta Li \&" Ta Li \e Ta Li \en .El .It Backslash A backslash preserves the literal meaning of the following character, with the exception of the newline character .Pq Ql \en . A backslash preceding a newline is treated as a line continuation. .El .Ss Keywords Keywords or reserved words are words that have special meaning to the shell and are recognized at the beginning of a line and after a control operator. The following are keywords: .Bl -column "doneXX" "elifXX" "elseXX" "untilXX" "whileX" -offset center .It Li \&! Ta { Ta } Ta Ic case Ta Ic do .It Ic done Ta Ic elif Ta Ic else Ta Ic esac Ta Ic fi .It Ic for Ta Ic if Ta Ic then Ta Ic until Ta Ic while .El .Ss Aliases An alias is a name and corresponding value set using the .Ic alias built-in command. Wherever the command word of a simple command may occur, and after checking for keywords if a keyword may occur, the shell checks the word to see if it matches an alias. If it does, it replaces it in the input stream with its value. For example, if there is an alias called .Dq Li lf with the value .Dq Li "ls -F" , then the input .Pp .Dl "lf foobar" .Pp would become .Pp .Dl "ls -F foobar" .Pp Aliases are also recognized after an alias whose value ends with a space or tab. For example, if there is also an alias called .Dq Li nohup with the value .Dq Li "nohup " , then the input .Pp .Dl "nohup lf foobar" .Pp would become .Pp .Dl "nohup ls -F foobar" .Pp Aliases provide a convenient way for naive users to create shorthands for commands without having to learn how to create functions with arguments. Using aliases in scripts is discouraged because the command that defines them must be executed before the code that uses them is parsed. This is fragile and not portable. .Pp An alias name may be escaped in a command line, so that it is not replaced by its alias value, by using quoting characters within or adjacent to the alias name. This is most often done by prefixing an alias name with a backslash to execute a function, built-in, or normal program with the same name. See the .Sx Quoting subsection. .Ss Commands The shell interprets the words it reads according to a language, the specification of which is outside the scope of this man page (refer to the BNF in the .St -p1003.2 document). Essentially though, a line is read and if the first word of the line (or after a control operator) is not a keyword, then the shell has recognized a simple command. Otherwise, a complex command or some other special construct may have been recognized. .Ss Simple Commands If a simple command has been recognized, the shell performs the following actions: .Bl -enum .It Leading words of the form .Dq Li name=value are stripped off and assigned to the environment of the simple command (they do not affect expansions). Redirection operators and their arguments (as described below) are stripped off and saved for processing. .It The remaining words are expanded as described in the section called .Sx Word Expansions , and the first remaining word is considered the command name and the command is located. The remaining words are considered the arguments of the command. If no command name resulted, then the .Dq Li name=value variable assignments recognized in 1) affect the current shell. .It Redirections are performed as described in the next section. .El .Ss Redirections Redirections are used to change where a command reads its input or sends its output. In general, redirections open, close, or duplicate an existing reference to a file. The overall format used for redirection is: .Pp .D1 Oo Ar n Oc Ar redir-op file .Pp The .Ar redir-op is one of the redirection operators mentioned previously. The following gives some examples of how these operators can be used. Note that stdin and stdout are commonly used abbreviations for standard input and standard output respectively. .Bl -tag -width "1234567890XX" -offset indent .It Oo Ar n Oc Ns Li > Ar file redirect stdout (or file descriptor .Ar n ) to .Ar file .It Oo Ar n Oc Ns Li >| Ar file same as above, but override the .Fl C option .It Oo Ar n Oc Ns Li >> Ar file append stdout (or file descriptor .Ar n ) to .Ar file .It Oo Ar n Oc Ns Li < Ar file redirect stdin (or file descriptor .Ar n ) from .Ar file .It Oo Ar n Oc Ns Li <> Ar file redirect stdin (or file descriptor .Ar n ) to and from .Ar file .It Oo Ar n1 Oc Ns Li <& Ns Ar n2 duplicate stdin (or file descriptor .Ar n1 ) from file descriptor .Ar n2 .It Oo Ar n Oc Ns Li <&- close stdin (or file descriptor .Ar n ) .It Oo Ar n1 Oc Ns Li >& Ns Ar n2 duplicate stdout (or file descriptor .Ar n1 ) to file descriptor .Ar n2 .It Oo Ar n Oc Ns Li >&- close stdout (or file descriptor .Ar n ) .El .Pp The following redirection is often called a .Dq here-document . .Bd -unfilled -offset indent .Oo Ar n Oc Ns Li << Ar delimiter .Ar here-doc-text .Ar ... .Ar delimiter .Ed .Pp All the text on successive lines up to the delimiter is saved away and made available to the command on standard input, or file descriptor .Ar n if it is specified. If the .Ar delimiter as specified on the initial line is quoted, then the .Ar here-doc-text is treated literally, otherwise the text is subjected to parameter expansion, command substitution, and arithmetic expansion (as described in the section on .Sx Word Expansions ) . If the operator is .Dq Li <<- instead of .Dq Li << , then leading tabs in the .Ar here-doc-text are stripped. .Ss Search and Execution There are three types of commands: shell functions, built-in commands, and normal programs. The command is searched for (by name) in that order. The three types of commands are all executed in a different way. .Pp When a shell function is executed, all of the shell positional parameters (except .Li $0 , which remains unchanged) are set to the arguments of the shell function. The variables which are explicitly placed in the environment of the command (by placing assignments to them before the function name) are made local to the function and are set to the values given. Then the command given in the function definition is executed. The positional parameters are restored to their original values when the command completes. This all occurs within the current shell. .Pp Shell built-in commands are executed internally to the shell, without spawning a new process. There are two kinds of built-in commands: regular and special. Assignments before special builtins persist after they finish executing and assignment errors, redirection errors and certain operand errors cause a script to be aborted. Special builtins cannot be overridden with a function. Both regular and special builtins can affect the shell in ways normal programs cannot. .Pp Otherwise, if the command name does not match a function or built-in command, the command is searched for as a normal program in the file system (as described in the next section). When a normal program is executed, the shell runs the program, passing the arguments and the environment to the program. If the program is not a normal executable file (i.e., if it does not begin with the .Dq "magic number" whose ASCII representation is .Dq Li #! , resulting in an .Er ENOEXEC return value from .Xr execve 2 ) but appears to be a text file, the shell will run a new instance of .Nm to interpret it. .Pp Note that previous versions of this document and the source code itself misleadingly and sporadically refer to a shell script without a magic number as a .Dq "shell procedure" . .Ss Path Search When locating a command, the shell first looks to see if it has a shell function by that name. Then it looks for a built-in command by that name. If a built-in command is not found, one of two things happen: .Bl -enum .It Command names containing a slash are simply executed without performing any searches. .It The shell searches each entry in the .Va PATH variable in turn for the command. The value of the .Va PATH variable should be a series of entries separated by colons. Each entry consists of a directory name. The current directory may be indicated implicitly by an empty directory name, or explicitly by a single period. .El .Ss Command Exit Status Each command has an exit status that can influence the behavior of other shell commands. The paradigm is that a command exits with zero for normal or success, and non-zero for failure, error, or a false indication. The man page for each command should indicate the various exit codes and what they mean. Additionally, the built-in commands return exit codes, as does an executed shell function. .Pp If a command is terminated by a signal, its exit status is greater than 128. The signal name can be found by passing the exit status to .Li kill -l . .Pp If there is no command word, the exit status is the exit status of the last command substitution executed, or zero if the command does not contain any command substitutions. .Ss Complex Commands Complex commands are combinations of simple commands with control operators or keywords, together creating a larger complex command. More generally, a command is one of the following: .Bl -item -offset indent .It simple command .It pipeline .It list or compound-list .It compound command .It function definition .El .Pp Unless otherwise stated, the exit status of a command is that of the last simple command executed by the command, or zero if no simple command was executed. .Ss Pipelines A pipeline is a sequence of one or more commands separated by the control operator .Ql \&| . The standard output of all but the last command is connected to the standard input of the next command. The standard output of the last command is inherited from the shell, as usual. .Pp The format for a pipeline is: .Pp .D1 Oo Li \&! Oc Ar command1 Op Li \&| Ar command2 ... .Pp The standard output of .Ar command1 is connected to the standard input of .Ar command2 . The standard input, standard output, or both of a command is considered to be assigned by the pipeline before any redirection specified by redirection operators that are part of the command. .Pp Note that unlike some other shells, .Nm executes each process in a pipeline with more than one command in a subshell environment and as a child of the .Nm process. .Pp If the pipeline is not in the background (discussed later), the shell waits for all commands to complete. .Pp If the keyword .Ic !\& does not precede the pipeline, the exit status is the exit status of the last command specified in the pipeline if the .Cm pipefail option is not set or all commands returned zero, or the last non-zero exit status of any command in the pipeline otherwise. Otherwise, the exit status is the logical NOT of that exit status. That is, if that status is zero, the exit status is 1; if that status is greater than zero, the exit status is zero. .Pp Because pipeline assignment of standard input or standard output or both takes place before redirection, it can be modified by redirection. For example: .Pp .Dl "command1 2>&1 | command2" .Pp sends both the standard output and standard error of .Ar command1 to the standard input of .Ar command2 . .Pp A .Ql \&; or newline terminator causes the preceding AND-OR-list (described below in the section called .Sx Short-Circuit List Operators ) to be executed sequentially; an .Ql & causes asynchronous execution of the preceding AND-OR-list. .Ss Background Commands (&) If a command is terminated by the control operator ampersand .Pq Ql & , the shell executes the command in a subshell environment (see .Sx Grouping Commands Together below) and asynchronously; the shell does not wait for the command to finish before executing the next command. .Pp The format for running a command in background is: .Pp .D1 Ar command1 Li & Op Ar command2 Li & Ar ... .Pp If the shell is not interactive, the standard input of an asynchronous command is set to .Pa /dev/null . .Pp The exit status is zero. .Ss Lists (Generally Speaking) A list is a sequence of zero or more commands separated by newlines, semicolons, or ampersands, and optionally terminated by one of these three characters. The commands in a list are executed in the order they are written. If command is followed by an ampersand, the shell starts the command and immediately proceeds onto the next command; otherwise it waits for the command to terminate before proceeding to the next one. .Ss Short-Circuit List Operators .Dq Li && and .Dq Li || are AND-OR list operators. .Dq Li && executes the first command, and then executes the second command if the exit status of the first command is zero. .Dq Li || is similar, but executes the second command if the exit status of the first command is nonzero. .Dq Li && and .Dq Li || both have the same priority. .Ss Flow-Control Constructs (if, while, for, case) The syntax of the .Ic if command is: .Bd -unfilled -offset indent -compact .Ic if Ar list .Ic then Ar list .Oo Ic elif Ar list .Ic then Ar list Oc Ar ... .Op Ic else Ar list .Ic fi .Ed .Pp The exit status is that of selected .Ic then or .Ic else list, or zero if no list was selected. .Pp The syntax of the .Ic while command is: .Bd -unfilled -offset indent -compact .Ic while Ar list .Ic do Ar list .Ic done .Ed .Pp The two lists are executed repeatedly while the exit status of the first list is zero. The .Ic until command is similar, but has the word .Ic until in place of .Ic while , which causes it to repeat until the exit status of the first list is zero. .Pp The exit status is that of the last execution of the second list, or zero if it was never executed. .Pp The syntax of the .Ic for command is: .Bd -unfilled -offset indent -compact .Ic for Ar variable Op Ic in Ar word ... .Ic do Ar list .Ic done .Ed .Pp If .Ic in and the following words are omitted, .Ic in Li \&"$@\&" is used instead. The words are expanded, and then the list is executed repeatedly with the variable set to each word in turn. The .Ic do and .Ic done commands may be replaced with .Ql { and .Ql } . .Pp The syntax of the .Ic break and .Ic continue commands is: .D1 Ic break Op Ar num .D1 Ic continue Op Ar num .Pp The .Ic break command terminates the .Ar num innermost .Ic for or .Ic while loops. The .Ic continue command continues with the next iteration of the innermost loop. These are implemented as special built-in commands. .Pp The syntax of the .Ic case command is: .Bd -unfilled -offset indent -compact .Ic case Ar word Ic in .Ar pattern ) Ar list Li ;; .Ar ... .Ic esac .Ed .Pp The pattern can actually be one or more patterns (see .Sx Shell Patterns described later), separated by .Ql \&| characters. Tilde expansion, parameter expansion, command substitution, arithmetic expansion and quote removal are applied to the word. Then, each pattern is expanded in turn using tilde expansion, parameter expansion, command substitution and arithmetic expansion and the expanded form of the word is checked against it. If a match is found, the corresponding list is executed. If the selected list is terminated by the control operator .Ql ;& instead of .Ql ;; , execution continues with the next list, continuing until a list terminated with .Ql ;; or the end of the .Ic case command. .Ss Grouping Commands Together Commands may be grouped by writing either .Pp .Sm off .Bd -literal -offset -ident .Po Ar list Pc .Ed .Sm on .Pp or .Bd -literal -offset -ident .No { Ar list ; } .Ed .Pp The first form executes the commands in a subshell environment. A subshell environment has its own copy of: .Bl -enum .It The current working directory as set by .Ic cd . .It The file creation mask as set by .Ic umask . .It Resource limits as set by .Ic ulimit . .It References to open files. .It Traps as set by .Ic trap . .It Known jobs. .It Positional parameters and variables. .It Shell options. .It Shell functions. .It Shell aliases. .El .Pp These are copied from the parent shell environment, except that trapped (but not ignored) signals are reset to the default action and known jobs are cleared. Any changes do not affect the parent shell environment. .Pp A subshell environment may be implemented as a child process or differently. If job control is enabled in an interactive shell, commands grouped in parentheses can be suspended and continued as a unit. .Pp For compatibility with other shells, two open parentheses in sequence should be separated by whitespace. .Pp The second form never forks another shell, so it is slightly more efficient. Grouping commands together this way allows the user to redirect their output as though they were one program: .Bd -literal -offset indent { echo -n "hello"; echo " world"; } > greeting .Ed .Ss Functions The syntax of a function definition is .Pp .D1 Ar name Li \&( \&) Ar command .Pp A function definition is an executable statement; when executed it installs a function named .Ar name and returns an exit status of zero. The .Ar command is normally a list enclosed between .Ql { and .Ql } . .Pp Variables may be declared to be local to a function by using the .Ic local command. This should appear as the first statement of a function, and the syntax is: .Pp .D1 Ic local Oo Ar variable ... Oc Op Fl .Pp The .Ic local command is implemented as a built-in command. The exit status is zero unless the command is not in a function or a variable name is invalid. .Pp When a variable is made local, it inherits the initial value and exported and readonly flags from the variable with the same name in the surrounding scope, if there is one. Otherwise, the variable is initially unset. The shell uses dynamic scoping, so that if the variable .Va x is made local to function .Em f , which then calls function .Em g , references to the variable .Va x made inside .Em g will refer to the variable .Va x declared inside .Em f , not to the global variable named .Va x . .Pp The only special parameter that can be made local is .Ql - . Making .Ql - local causes any shell options (including those that only have long names) that are changed via the .Ic set command inside the function to be restored to their original values when the function returns. .Pp The syntax of the .Ic return command is .Pp .D1 Ic return Op Ar exitstatus .Pp It terminates the current executional scope, returning from the closest nested function or sourced script; if no function or sourced script is being executed, it exits the shell instance. The .Ic return command is implemented as a special built-in command. .Ss Variables and Parameters The shell maintains a set of parameters. A parameter denoted by a name (consisting solely of alphabetics, numerics, and underscores, and starting with an alphabetic or an underscore) is called a variable. When starting up, the shell turns all environment variables with valid names into shell variables. New variables can be set using the form .Pp .D1 Ar name Ns = Ns Ar value .Pp A parameter can also be denoted by a number or a special character as explained below. .Pp Assignments are expanded differently from other words: tilde expansion is also performed after the equals sign and after any colon and usernames are also terminated by colons, and field splitting and pathname expansion are not performed. .Pp This special expansion applies not only to assignments that form a simple command by themselves or precede a command word, but also to words passed to the .Ic export , .Ic local or .Ic readonly built-in commands that have this form. For this, the builtin's name must be literal (not the result of an expansion) and may optionally be preceded by one or more literal instances of .Ic command without options. .Ss Positional Parameters A positional parameter is a parameter denoted by a number greater than zero. The shell sets these initially to the values of its command line arguments that follow the name of the shell script. The .Ic set built-in command can also be used to set or reset them. .Ss Special Parameters Special parameters are parameters denoted by a single special character or the digit zero. They are shown in the following list, exactly as they would appear in input typed by the user or in the source of a shell script. .Bl -hang .It Li $* Expands to the positional parameters, starting from one. When the expansion occurs within a double-quoted string it expands to a single field with the value of each parameter separated by the first character of the .Va IFS variable, or by a space if .Va IFS is unset. .It Li $@ Expands to the positional parameters, starting from one. When the expansion occurs within double-quotes, each positional parameter expands as a separate argument. If there are no positional parameters, the expansion of .Li @ generates zero arguments, even when .Li @ is double-quoted. What this basically means, for example, is if .Li $1 is .Dq Li abc and .Li $2 is .Dq Li "def ghi" , then .Li \&"$@\&" expands to the two arguments: .Bd -literal -offset indent "abc" "def ghi" .Ed .It Li $# Expands to the number of positional parameters. .It Li $? Expands to the exit status of the most recent pipeline. .It Li $- (hyphen) Expands to the current option flags (the single-letter option names concatenated into a string) as specified on invocation, by the .Ic set built-in command, or implicitly by the shell. .It Li $$ Expands to the process ID of the invoked shell. A subshell retains the same value of .Va $ as its parent. .It Li $! Expands to the process ID of the most recent background command executed from the current shell. For a pipeline, the process ID is that of the last command in the pipeline. If this parameter is referenced, the shell will remember the process ID and its exit status until the .Ic wait built-in command reports completion of the process. .It Li $0 (zero) Expands to the name of the shell script if passed on the command line, the .Ar name operand if given (with .Fl c ) or otherwise argument 0 passed to the shell. .El .Ss Special Variables The following variables are set by the shell or have special meaning to it: .Bl -tag -width ".Va HISTSIZE" .It Va CDPATH The search path used with the .Ic cd built-in. .It Va EDITOR The fallback editor used with the .Ic fc built-in. If not set, the default editor is .Xr ed 1 . .It Va FCEDIT The default editor used with the .Ic fc built-in. +.It Va HISTFILE +File used for persistent history storage. +If unset +.Pa ~/.sh_history +will be used. +If set but empty or +.Va HISTSIZE +is set to 0 +the shell will not load and save the history. .It Va HISTSIZE The number of previous commands that are accessible. .It Va HOME The user's home directory, used in tilde expansion and as a default directory for the .Ic cd built-in. .It Va IFS Input Field Separators. This is initialized at startup to .Aq space , .Aq tab , and .Aq newline in that order. This value also applies if .Va IFS is unset, but not if it is set to the empty string. See the .Sx White Space Splitting section for more details. .It Va LINENO The current line number in the script or function. .It Va MAIL The name of a mail file, that will be checked for the arrival of new mail. Overridden by .Va MAILPATH . .It Va MAILPATH A colon .Pq Ql \&: separated list of file names, for the shell to check for incoming mail. This variable overrides the .Va MAIL setting. There is a maximum of 10 mailboxes that can be monitored at once. .It Va OPTIND The index of the next argument to be processed by .Ic getopts . This is initialized to 1 at startup. .It Va PATH The default search path for executables. See the .Sx Path Search section for details. .It Va PPID The parent process ID of the invoked shell. This is set at startup unless this variable is in the environment. A later change of parent process ID is not reflected. A subshell retains the same value of .Va PPID . .It Va PS1 The primary prompt string, which defaults to .Dq Li "$ " , unless you are the superuser, in which case it defaults to .Dq Li "# " . .Va PS1 may include any of the following formatting sequences, which are replaced by the given information: .Bl -tag -width indent .It Li \eH This system's fully-qualified hostname (FQDN). .It Li \eh This system's hostname. .It Li \eu User name. .It Li \eW The final component of the current working directory. .It Li \ew The entire path of the current working directory. .It Li \e$ Superuser status. .Dq Li "$" for normal users and .Dq Li "#" for superusers. .It Li \e\e A literal backslash. .El .It Va PS2 The secondary prompt string, which defaults to .Dq Li "> " . .Va PS2 may include any of the formatting sequences from .Va PS1 . .It Va PS4 The prefix for the trace output (if .Fl x is active). The default is .Dq Li "+ " . .El .Ss Word Expansions This clause describes the various expansions that are performed on words. Not all expansions are performed on every word, as explained later. .Pp Tilde expansions, parameter expansions, command substitutions, arithmetic expansions, and quote removals that occur within a single word expand to a single field. It is only field splitting or pathname expansion that can create multiple fields from a single word. The single exception to this rule is the expansion of the special parameter .Va @ within double-quotes, as was described above. .Pp The order of word expansion is: .Bl -enum .It Tilde Expansion, Parameter Expansion, Command Substitution, Arithmetic Expansion (these all occur at the same time). .It Field Splitting is performed on fields generated by step (1) unless the .Va IFS variable is null. .It Pathname Expansion (unless the .Fl f option is in effect). .It Quote Removal. .El .Pp The .Ql $ character is used to introduce parameter expansion, command substitution, or arithmetic expansion. .Ss Tilde Expansion (substituting a user's home directory) A word beginning with an unquoted tilde character .Pq Ql ~ is subjected to tilde expansion. All the characters up to a slash .Pq Ql / or the end of the word are treated as a username and are replaced with the user's home directory. If the username is missing (as in .Pa ~/foobar ) , the tilde is replaced with the value of the .Va HOME variable (the current user's home directory). .Ss Parameter Expansion The format for parameter expansion is as follows: .Pp .D1 Li ${ Ns Ar expression Ns Li } .Pp where .Ar expression consists of all characters until the matching .Ql } . Any .Ql } escaped by a backslash or within a single-quoted or double-quoted string, and characters in embedded arithmetic expansions, command substitutions, and variable expansions, are not examined in determining the matching .Ql } . If the variants with .Ql + , .Ql - , .Ql = or .Ql ?\& occur within a double-quoted string, as an extension there may be unquoted parts (via double-quotes inside the expansion); .Ql } within such parts are also not examined in determining the matching .Ql } . .Pp The simplest form for parameter expansion is: .Pp .D1 Li ${ Ns Ar parameter Ns Li } .Pp The value, if any, of .Ar parameter is substituted. .Pp The parameter name or symbol can be enclosed in braces, which are optional except for positional parameters with more than one digit or when parameter is followed by a character that could be interpreted as part of the name. If a parameter expansion occurs inside double-quotes: .Bl -enum .It Field splitting is not performed on the results of the expansion, with the exception of the special parameter .Va @ . .It Pathname expansion is not performed on the results of the expansion. .El .Pp In addition, a parameter expansion can be modified by using one of the following formats. .Bl -tag -width indent .It Li ${ Ns Ar parameter Ns Li :- Ns Ar word Ns Li } Use Default Values. If .Ar parameter is unset or null, the expansion of .Ar word is substituted; otherwise, the value of .Ar parameter is substituted. .It Li ${ Ns Ar parameter Ns Li := Ns Ar word Ns Li } Assign Default Values. If .Ar parameter is unset or null, the expansion of .Ar word is assigned to .Ar parameter . In all cases, the final value of .Ar parameter is substituted. Quoting inside .Ar word does not prevent field splitting or pathname expansion. Only variables, not positional parameters or special parameters, can be assigned in this way. .It Li ${ Ns Ar parameter Ns Li :? Ns Oo Ar word Oc Ns Li } Indicate Error if Null or Unset. If .Ar parameter is unset or null, the expansion of .Ar word (or a message indicating it is unset if .Ar word is omitted) is written to standard error and the shell exits with a nonzero exit status. Otherwise, the value of .Ar parameter is substituted. An interactive shell need not exit. .It Li ${ Ns Ar parameter Ns Li :+ Ns Ar word Ns Li } Use Alternate Value. If .Ar parameter is unset or null, null is substituted; otherwise, the expansion of .Ar word is substituted. .El .Pp In the parameter expansions shown previously, use of the colon in the format results in a test for a parameter that is unset or null; omission of the colon results in a test for a parameter that is only unset. .Pp The .Ar word inherits the type of quoting (unquoted, double-quoted or here-document) from the surroundings, with the exception that a backslash that quotes a closing brace is removed during quote removal. .Bl -tag -width indent .It Li ${# Ns Ar parameter Ns Li } String Length. The length in characters of the value of .Ar parameter . .El .Pp The following four varieties of parameter expansion provide for substring processing. In each case, pattern matching notation (see .Sx Shell Patterns ) , rather than regular expression notation, is used to evaluate the patterns. If parameter is one of the special parameters .Va * or .Va @ , the result of the expansion is unspecified. Enclosing the full parameter expansion string in double-quotes does not cause the following four varieties of pattern characters to be quoted, whereas quoting characters within the braces has this effect. .Bl -tag -width indent .It Li ${ Ns Ar parameter Ns Li % Ns Ar word Ns Li } Remove Smallest Suffix Pattern. The .Ar word is expanded to produce a pattern. The parameter expansion then results in .Ar parameter , with the smallest portion of the suffix matched by the pattern deleted. .It Li ${ Ns Ar parameter Ns Li %% Ns Ar word Ns Li } Remove Largest Suffix Pattern. The .Ar word is expanded to produce a pattern. The parameter expansion then results in .Ar parameter , with the largest portion of the suffix matched by the pattern deleted. .It Li ${ Ns Ar parameter Ns Li # Ns Ar word Ns Li } Remove Smallest Prefix Pattern. The .Ar word is expanded to produce a pattern. The parameter expansion then results in .Ar parameter , with the smallest portion of the prefix matched by the pattern deleted. .It Li ${ Ns Ar parameter Ns Li ## Ns Ar word Ns Li } Remove Largest Prefix Pattern. The .Ar word is expanded to produce a pattern. The parameter expansion then results in .Ar parameter , with the largest portion of the prefix matched by the pattern deleted. .El .Ss Command Substitution Command substitution allows the output of a command to be substituted in place of the command name itself. Command substitution occurs when the command is enclosed as follows: .Pp .D1 Li $( Ns Ar command Ns Li )\& .Pp or the backquoted version: .Pp .D1 Li ` Ns Ar command Ns Li ` .Pp The shell expands the command substitution by executing command and replacing the command substitution with the standard output of the command, removing sequences of one or more newlines at the end of the substitution. Embedded newlines before the end of the output are not removed; however, during field splitting, they may be translated into spaces depending on the value of .Va IFS and the quoting that is in effect. The command is executed in a subshell environment, except that the built-in commands .Ic jobid , .Ic jobs , and .Ic trap return information about the parent shell environment and .Ic times returns information about the same process if they are the only command in a command substitution. .Pp If a command substitution of the .Li $( form begins with a subshell, the .Li $( and .Li (\& must be separated by whitespace to avoid ambiguity with arithmetic expansion. .Ss Arithmetic Expansion Arithmetic expansion provides a mechanism for evaluating an arithmetic expression and substituting its value. The format for arithmetic expansion is as follows: .Pp .D1 Li $(( Ns Ar expression Ns Li )) .Pp The .Ar expression is treated as if it were in double-quotes, except that a double-quote inside the expression is not treated specially. The shell expands all tokens in the .Ar expression for parameter expansion, command substitution, arithmetic expansion and quote removal. .Pp The allowed expressions are a subset of C expressions, summarized below. .Bl -tag -width "Variables" -offset indent .It Values All values are of type .Ft intmax_t . .It Constants Decimal, octal (starting with .Li 0 ) and hexadecimal (starting with .Li 0x ) integer constants. .It Variables Shell variables can be read and written and contain integer constants. .It Unary operators .Li "! ~ + -" .It Binary operators .Li "* / % + - << >> < <= > >= == != & ^ | && ||"\& .It Assignment operators .Li "= += -= *= /= %= <<= >>= &= ^= |=" .It Conditional operator .Li "? :"\& .El .Pp The result of the expression is substituted in decimal. .Ss White Space Splitting (Field Splitting) In certain contexts, after parameter expansion, command substitution, and arithmetic expansion the shell scans the results of expansions and substitutions that did not occur in double-quotes for field splitting and multiple fields can result. .Pp Characters in .Va IFS that are whitespace .Po .Aq space , .Aq tab , and .Aq newline .Pc are treated differently from other characters in .Va IFS . .Pp Whitespace in .Va IFS at the beginning or end of a word is discarded. .Pp Subsequently, a field is delimited by either .Bl -enum .It a non-whitespace character in .Va IFS with any whitespace in .Va IFS surrounding it, or .It one or more whitespace characters in .Va IFS . .El .Pp If a word ends with a non-whitespace character in .Va IFS , there is no empty field after this character. .Pp If no field is delimited, the word is discarded. In particular, if a word consists solely of an unquoted substitution and the result of the substitution is null, it is removed by field splitting even if .Va IFS is null. .Ss Pathname Expansion (File Name Generation) Unless the .Fl f option is set, file name generation is performed after word splitting is complete. Each word is viewed as a series of patterns, separated by slashes. The process of expansion replaces the word with the names of all existing files whose names can be formed by replacing each pattern with a string that matches the specified pattern. There are two restrictions on this: first, a pattern cannot match a string containing a slash, and second, a pattern cannot match a string starting with a period unless the first character of the pattern is a period. The next section describes the patterns used for Pathname Expansion, the four varieties of parameter expansion for substring processing and the .Ic case command. .Ss Shell Patterns A pattern consists of normal characters, which match themselves, and meta-characters. The meta-characters are .Ql * , .Ql \&? , and .Ql \&[ . These characters lose their special meanings if they are quoted. When command or variable substitution is performed and the dollar sign or back quotes are not double-quoted, the value of the variable or the output of the command is scanned for these characters and they are turned into meta-characters. .Pp An asterisk .Pq Ql * matches any string of characters. A question mark .Pq Ql \&? matches any single character. A left bracket .Pq Ql \&[ introduces a character class. The end of the character class is indicated by a .Ql \&] ; if the .Ql \&] is missing then the .Ql \&[ matches a .Ql \&[ rather than introducing a character class. A character class matches any of the characters between the square brackets. A locale-dependent range of characters may be specified using a minus sign. A named class of characters (see .Xr wctype 3 ) may be specified by surrounding the name with .Ql \&[:\& and .Ql :\&] . For example, .Ql \&[\&[:alpha:\&]\&] is a shell pattern that matches a single letter. The character class may be complemented by making an exclamation point .Pq Ql !\& the first character of the character class. A caret .Pq Ql ^ has the same effect but is non-standard. .Pp To include a .Ql \&] in a character class, make it the first character listed (after the .Ql \&! or .Ql ^ , if any). To include a .Ql - , make it the first or last character listed. .Ss Built-in Commands This section lists the built-in commands. .Bl -tag -width indent .It Ic \&: A null command that returns a 0 (true) exit value. .It Ic \&. Ar file The commands in the specified file are read and executed by the shell. The .Ic return command may be used to return to the .Ic \&. command's caller. If .Ar file contains any .Ql / characters, it is used as is. Otherwise, the shell searches the .Va PATH for the file. If it is not found in the .Va PATH , it is sought in the current working directory. .It Ic \&[ A built-in equivalent of .Xr test 1 . .It Ic alias Oo Ar name Ns Oo = Ns Ar string Oc ... Oc If .Ar name Ns = Ns Ar string is specified, the shell defines the alias .Ar name with value .Ar string . If just .Ar name is specified, the value of the alias .Ar name is printed. With no arguments, the .Ic alias built-in command prints the names and values of all defined aliases (see .Ic unalias ) . Alias values are written with appropriate quoting so that they are suitable for re-input to the shell. Also see the .Sx Aliases subsection. .It Ic bg Op Ar job ... Continue the specified jobs (or the current job if no jobs are given) in the background. .It Ic bind Oo Fl aeklrsv Oc Oo Ar key Oo Ar command Oc Oc List or alter key bindings for the line editor. This command is documented in .Xr editrc 5 . .It Ic break Op Ar num See the .Sx Flow-Control Constructs subsection. .It Ic builtin Ar cmd Op Ar arg ... Execute the specified built-in command, .Ar cmd . This is useful when the user wishes to override a shell function with the same name as a built-in command. .It Ic cd Oo Fl L | P Oc Oo Fl e Oc Op Ar directory .It Ic cd Fl Switch to the specified .Ar directory , to the directory specified in the .Va HOME environment variable if no .Ar directory is specified or to the directory specified in the .Va OLDPWD environment variable if .Ar directory is .Fl . If .Ar directory does not begin with .Pa / , \&. , or .Pa .. , then the directories listed in the .Va CDPATH variable will be searched for the specified .Ar directory . If .Va CDPATH is unset, the current directory is searched. The format of .Va CDPATH is the same as that of .Va PATH . In an interactive shell, the .Ic cd command will print out the name of the directory that it actually switched to if the .Va CDPATH mechanism was used or if .Ar directory was .Fl . .Pp If the .Fl P option is specified, .Pa .. is handled physically and symbolic links are resolved before .Pa .. components are processed. If the .Fl L option is specified, .Pa .. is handled logically. This is the default. .Pp The .Fl e option causes .Ic cd to return exit status 1 if the full pathname of the new directory cannot be determined reliably or at all. Normally this is not considered an error, although a warning is printed. .Pp If changing the directory fails, the exit status is greater than 1. If the directory is changed, the exit status is 0, or also 1 if .Fl e was given. .It Ic chdir A synonym for the .Ic cd built-in command. .It Ic command Oo Fl p Oc Op Ar utility Op Ar argument ... .It Ic command Oo Fl p Oc Fl v Ar utility .It Ic command Oo Fl p Oc Fl V Ar utility The first form of invocation executes the specified .Ar utility , ignoring shell functions in the search. If .Ar utility is a special builtin, it is executed as if it were a regular builtin. .Pp If the .Fl p option is specified, the command search is performed using a default value of .Va PATH that is guaranteed to find all of the standard utilities. .Pp If the .Fl v option is specified, .Ar utility is not executed but a description of its interpretation by the shell is printed. For ordinary commands the output is the path name; for shell built-in commands, shell functions and keywords only the name is written. Aliases are printed as .Dq Ic alias Ar name Ns = Ns Ar value . .Pp The .Fl V option is identical to .Fl v except for the output. It prints .Dq Ar utility Ic is Ar description where .Ar description is either the path name to .Ar utility , a special shell builtin, a shell builtin, a shell function, a shell keyword or an alias for .Ar value . .It Ic continue Op Ar num See the .Sx Flow-Control Constructs subsection. .It Ic echo Oo Fl e | n Oc Op Ar string ... Print a space-separated list of the arguments to the standard output and append a newline character. .Bl -tag -width indent .It Fl n Suppress the output of the trailing newline. .It Fl e Process C-style backslash escape sequences. The .Ic echo command understands the following character escapes: .Bl -tag -width indent .It \ea Alert (ring the terminal bell) .It \eb Backspace .It \ec Suppress the trailing newline (this has the side-effect of truncating the line if it is not the last character) .It \ee The ESC character (ASCII 0x1b) .It \ef Formfeed .It \en Newline .It \er Carriage return .It \et Horizontal tab .It \ev Vertical tab .It \e\e Literal backslash .It \e0nnn (Zero) The character whose octal value is .Ar nnn .El .Pp If .Ar string is not enclosed in quotes then the backslash itself must be escaped with a backslash to protect it from the shell. For example .Bd -literal -offset indent $ echo -e "a\evb" a b $ echo -e a\e\evb a b $ echo -e "a\e\eb" a\eb $ echo -e a\e\e\e\eb a\eb .Ed .El .Pp Only one of the .Fl e and .Fl n options may be specified. .It Ic eval Ar string ... Concatenate all the arguments with spaces. Then re-parse and execute the command. .It Ic exec Op Ar command Op arg ... Unless .Ar command is omitted, the shell process is replaced with the specified program (which must be a real program, not a shell built-in command or function). Any redirections on the .Ic exec command are marked as permanent, so that they are not undone when the .Ic exec command finishes. .It Ic exit Op Ar exitstatus Terminate the shell process. If .Ar exitstatus is given it is used as the exit status of the shell. Otherwise, if the shell is executing an .Cm EXIT trap, the exit status of the last command before the trap is used; if the shell is executing a trap for a signal, the shell exits by resending the signal to itself. Otherwise, the exit status of the preceding command is used. The exit status should be an integer between 0 and 255. .It Ic export Ar name ... .It Ic export Op Fl p The specified names are exported so that they will appear in the environment of subsequent commands. The only way to un-export a variable is to .Ic unset it. The shell allows the value of a variable to be set at the same time as it is exported by writing .Pp .D1 Ic export Ar name Ns = Ns Ar value .Pp With no arguments the .Ic export command lists the names of all exported variables. If the .Fl p option is specified, the exported variables are printed as .Dq Ic export Ar name Ns = Ns Ar value lines, suitable for re-input to the shell. .It Ic false A null command that returns a non-zero (false) exit value. .It Ic fc Oo Fl e Ar editor Oc Op Ar first Op Ar last .It Ic fc Fl l Oo Fl nr Oc Op Ar first Op Ar last .It Ic fc Fl s Oo Ar old Ns = Ns Ar new Oc Op Ar first The .Ic fc built-in command lists, or edits and re-executes, commands previously entered to an interactive shell. .Bl -tag -width indent .It Fl e Ar editor Use the editor named by .Ar editor to edit the commands. The .Ar editor string is a command name, subject to search via the .Va PATH variable. The value in the .Va FCEDIT variable is used as a default when .Fl e is not specified. If .Va FCEDIT is null or unset, the value of the .Va EDITOR variable is used. If .Va EDITOR is null or unset, .Xr ed 1 is used as the editor. .It Fl l No (ell) List the commands rather than invoking an editor on them. The commands are written in the sequence indicated by the .Ar first and .Ar last operands, as affected by .Fl r , with each command preceded by the command number. .It Fl n Suppress command numbers when listing with .Fl l . .It Fl r Reverse the order of the commands listed (with .Fl l ) or edited (with neither .Fl l nor .Fl s ) . .It Fl s Re-execute the command without invoking an editor. .It Ar first .It Ar last Select the commands to list or edit. The number of previous commands that can be accessed are determined by the value of the .Va HISTSIZE variable. The value of .Ar first or .Ar last or both are one of the following: .Bl -tag -width indent .It Oo Cm + Oc Ns Ar num A positive number representing a command number; command numbers can be displayed with the .Fl l option. .It Fl Ar num A negative decimal number representing the command that was executed .Ar num of commands previously. For example, \-1 is the immediately previous command. .It Ar string A string indicating the most recently entered command that begins with that string. If the .Ar old Ns = Ns Ar new operand is not also specified with .Fl s , the string form of the first operand cannot contain an embedded equal sign. .El .El .Pp The following variables affect the execution of .Ic fc : .Bl -tag -width ".Va HISTSIZE" .It Va FCEDIT Name of the editor to use for history editing. .It Va HISTSIZE The number of previous commands that are accessible. .El .It Ic fg Op Ar job Move the specified .Ar job or the current job to the foreground. .It Ic getopts Ar optstring var The POSIX .Ic getopts command. The .Ic getopts command deprecates the older .Xr getopt 1 command. The first argument should be a series of letters, each possibly followed by a colon which indicates that the option takes an argument. The specified variable is set to the parsed option. The index of the next argument is placed into the shell variable .Va OPTIND . If an option takes an argument, it is placed into the shell variable .Va OPTARG . If an invalid option is encountered, .Ar var is set to .Ql \&? . It returns a false value (1) when it encounters the end of the options. A new set of arguments may be parsed by assigning .Li OPTIND=1 . .It Ic hash Oo Fl rv Oc Op Ar command ... The shell maintains a hash table which remembers the locations of commands. With no arguments whatsoever, the .Ic hash command prints out the contents of this table. .Pp With arguments, the .Ic hash command removes each specified .Ar command from the hash table (unless they are functions) and then locates it. With the .Fl v option, .Ic hash prints the locations of the commands as it finds them. The .Fl r option causes the .Ic hash command to delete all the entries in the hash table except for functions. .It Ic jobid Op Ar job Print the process IDs of the processes in the specified .Ar job . If the .Ar job argument is omitted, use the current job. .It Ic jobs Oo Fl lps Oc Op Ar job ... Print information about the specified jobs, or all jobs if no .Ar job argument is given. The information printed includes job ID, status and command name. .Pp If the .Fl l option is specified, the PID of each job is also printed. If the .Fl p option is specified, only the process IDs for the process group leaders are printed, one per line. If the .Fl s option is specified, only the PIDs of the job commands are printed, one per line. .It Ic kill A built-in equivalent of .Xr kill 1 that additionally supports sending signals to jobs. .It Ic local Oo Ar variable ... Oc Op Fl See the .Sx Functions subsection. .It Ic printf A built-in equivalent of .Xr printf 1 . .It Ic pwd Op Fl L | P Print the path of the current directory. The built-in command may differ from the program of the same name because the built-in command remembers what the current directory is rather than recomputing it each time. This makes it faster. However, if the current directory is renamed, the built-in version of .Xr pwd 1 will continue to print the old name for the directory. .Pp If the .Fl P option is specified, symbolic links are resolved. If the .Fl L option is specified, the shell's notion of the current directory is printed (symbolic links are not resolved). This is the default. .It Ic read Oo Fl p Ar prompt Oc Oo .Fl t Ar timeout Oc Oo Fl er Oc Ar variable ... The .Ar prompt is printed if the .Fl p option is specified and the standard input is a terminal. Then a line is read from the standard input. The trailing newline is deleted from the line and the line is split as described in the section on .Sx White Space Splitting (Field Splitting)\& above, and the pieces are assigned to the variables in order. If there are more pieces than variables, the remaining pieces (along with the characters in .Va IFS that separated them) are assigned to the last variable. If there are more variables than pieces, the remaining variables are assigned the null string. .Pp Backslashes are treated specially, unless the .Fl r option is specified. If a backslash is followed by a newline, the backslash and the newline will be deleted. If a backslash is followed by any other character, the backslash will be deleted and the following character will be treated as though it were not in .Va IFS , even if it is. .Pp If the .Fl t option is specified and the .Ar timeout elapses before a complete line of input is supplied, the .Ic read command will return an exit status as if terminated by .Dv SIGALRM without assigning any values. The .Ar timeout value may optionally be followed by one of .Ql s , .Ql m or .Ql h to explicitly specify seconds, minutes or hours. If none is supplied, .Ql s is assumed. .Pp The .Fl e option exists only for backward compatibility with older scripts. .Pp The exit status is 0 on success, 1 on end of file, between 2 and 128 if an error occurs and greater than 128 if a trapped signal interrupts .Ic read . .It Ic readonly Oo Fl p Oc Op Ar name ... Each specified .Ar name is marked as read only, so that it cannot be subsequently modified or unset. The shell allows the value of a variable to be set at the same time as it is marked read only by using the following form: .Pp .D1 Ic readonly Ar name Ns = Ns Ar value .Pp With no arguments the .Ic readonly command lists the names of all read only variables. If the .Fl p option is specified, the read-only variables are printed as .Dq Ic readonly Ar name Ns = Ns Ar value lines, suitable for re-input to the shell. .It Ic return Op Ar exitstatus See the .Sx Functions subsection. .It Ic set Oo Fl /+abCEefIimnpTuVvx Oc Oo Fl /+o Ar longname .Oc Op Fl - Ar arg ... The .Ic set command performs three different functions: .Bl -item .It With no arguments, it lists the values of all shell variables. .It If options are given, either in short form or using the long .Dq Fl /+o Ar longname form, it sets or clears the specified options as described in the section called .Sx Argument List Processing . .It If the .Dq Fl - option is specified, .Ic set will replace the shell's positional parameters with the subsequent arguments. If no arguments follow the .Dq Fl - option, all the positional parameters will be cleared, which is equivalent to executing the command .Dq Li "shift $#" . The .Dq Fl - flag may be omitted when specifying arguments to be used as positional replacement parameters. This is not recommended, because the first argument may begin with a dash .Pq Ql - or a plus .Pq Ql + , which the .Ic set command will interpret as a request to enable or disable options. .El .It Ic setvar Ar variable value Assigns the specified .Ar value to the specified .Ar variable . The .Ic setvar command is intended to be used in functions that assign values to variables whose names are passed as parameters. In general it is better to write .Dq Ar variable Ns = Ns Ar value rather than using .Ic setvar . .It Ic shift Op Ar n Shift the positional parameters .Ar n times, or once if .Ar n is not specified. A shift sets the value of .Li $1 to the value of .Li $2 , the value of .Li $2 to the value of .Li $3 , and so on, decreasing the value of .Li $# by one. For portability, shifting if there are zero positional parameters should be avoided, since the shell may abort. .It Ic test A built-in equivalent of .Xr test 1 . .It Ic times Print the amount of time spent executing the shell process and its children. The first output line shows the user and system times for the shell process itself, the second one contains the user and system times for the children. .It Ic trap Oo Ar action Oc Ar signal ... .It Ic trap Fl l Cause the shell to parse and execute .Ar action when any specified .Ar signal is received. The signals are specified by name or number. In addition, the pseudo-signal .Cm EXIT may be used to specify an .Ar action that is performed when the shell terminates. The .Ar action may be an empty string or a dash .Pq Ql - ; the former causes the specified signal to be ignored and the latter causes the default action to be taken. Omitting the .Ar action and using only signal numbers is another way to request the default action. In a subshell or utility environment, the shell resets trapped (but not ignored) signals to the default action. The .Ic trap command has no effect on signals that were ignored on entry to the shell. .Pp Option .Fl l causes the .Ic trap command to display a list of valid signal names. .It Ic true A null command that returns a 0 (true) exit value. .It Ic type Op Ar name ... Interpret each .Ar name as a command and print the resolution of the command search. Possible resolutions are: shell keyword, alias, special shell builtin, shell builtin, command, tracked alias and not found. For aliases the alias expansion is printed; for commands and tracked aliases the complete pathname of the command is printed. .It Ic ulimit Oo Fl HSabcdfklmnopstuvw Oc Op Ar limit Set or display resource limits (see .Xr getrlimit 2 ) . If .Ar limit is specified, the named resource will be set; otherwise the current resource value will be displayed. .Pp If .Fl H is specified, the hard limits will be set or displayed. While everybody is allowed to reduce a hard limit, only the superuser can increase it. The .Fl S option specifies the soft limits instead. When displaying limits, only one of .Fl S or .Fl H can be given. The default is to display the soft limits, and to set both the hard and the soft limits. .Pp Option .Fl a causes the .Ic ulimit command to display all resources. The parameter .Ar limit is not acceptable in this mode. .Pp The remaining options specify which resource value is to be displayed or modified. They are mutually exclusive. .Bl -tag -width indent .It Fl b Ar sbsize The maximum size of socket buffer usage, in bytes. .It Fl c Ar coredumpsize The maximal size of core dump files, in 512-byte blocks. Setting .Ar coredumpsize to 0 prevents core dump files from being created. .It Fl d Ar datasize The maximal size of the data segment of a process, in kilobytes. .It Fl f Ar filesize The maximal size of a file, in 512-byte blocks. .It Fl k Ar kqueues The maximal number of kqueues (see .Xr kqueue 2 ) for this user ID. .It Fl l Ar lockedmem The maximal size of memory that can be locked by a process, in kilobytes. .It Fl m Ar memoryuse The maximal resident set size of a process, in kilobytes. .It Fl n Ar nofiles The maximal number of descriptors that could be opened by a process. .It Fl o Ar umtxp The maximal number of process-shared locks (see .Xr pthread 3 ) for this user ID. .It Fl p Ar pseudoterminals The maximal number of pseudo-terminals for this user ID. .It Fl s Ar stacksize The maximal size of the stack segment, in kilobytes. .It Fl t Ar time The maximal amount of CPU time to be used by each process, in seconds. .It Fl u Ar userproc The maximal number of simultaneous processes for this user ID. .It Fl v Ar virtualmem The maximal virtual size of a process, in kilobytes. .It Fl w Ar swapuse The maximum amount of swap space reserved or used for this user ID, in kilobytes. .El .It Ic umask Oo Fl S Oc Op Ar mask Set the file creation mask (see .Xr umask 2 ) to the octal or symbolic (see .Xr chmod 1 ) value specified by .Ar mask . If the argument is omitted, the current mask value is printed. If the .Fl S option is specified, the output is symbolic, otherwise the output is octal. .It Ic unalias Oo Fl a Oc Op Ar name ... The specified alias names are removed. If .Fl a is specified, all aliases are removed. .It Ic unset Oo Fl fv Oc Ar name ... The specified variables or functions are unset and unexported. If the .Fl v option is specified or no options are given, the .Ar name arguments are treated as variable names. If the .Fl f option is specified, the .Ar name arguments are treated as function names. .It Ic wait Op Ar job ... Wait for each specified .Ar job to complete and return the exit status of the last process in the last specified .Ar job . If any .Ar job specified is unknown to the shell, it is treated as if it were a known job that exited with exit status 127. If no operands are given, wait for all jobs to complete and return an exit status of zero. .El .Ss Command Line Editing When .Nm is being used interactively from a terminal, the current command and the command history (see .Ic fc in .Sx Built-in Commands ) can be edited using .Nm vi Ns -mode command line editing. This mode uses commands similar to a subset of those described in the .Xr vi 1 man page. The command .Dq Li "set -o vi" (or .Dq Li "set -V" ) enables .Nm vi Ns -mode editing and places .Nm into .Nm vi insert mode. With .Nm vi Ns -mode enabled, .Nm can be switched between insert mode and command mode by typing .Aq ESC . Hitting .Aq return while in command mode will pass the line to the shell. .Pp Similarly, the .Dq Li "set -o emacs" (or .Dq Li "set -E" ) command can be used to enable a subset of .Nm emacs Ns -style command line editing features. .Sh ENVIRONMENT The following environment variables affect the execution of .Nm : .Bl -tag -width ".Ev LANGXXXXXX" .It Ev ENV Initialization file for interactive shells. .It Ev LANG , Ev LC_* Locale settings. These are inherited by children of the shell, and is used in a limited manner by the shell itself. .It Ev OLDPWD The previous current directory. This is used and updated by .Ic cd . .It Ev PWD An absolute pathname for the current directory, possibly containing symbolic links. This is used and updated by the shell. .It Ev TERM The default terminal setting for the shell. This is inherited by children of the shell, and is used in the history editing modes. .El .Pp Additionally, environment variables are turned into shell variables at startup, which may affect the shell as described under .Sx Special Variables . .Sh FILES .Bl -tag -width "/etc/suid_profileXX" -compact .It Pa ~/.profile User's login profile. .It Pa /etc/profile System login profile. .It Pa /etc/shells Shell database. .It Pa /etc/suid_profile Privileged shell profile. .El .Sh EXIT STATUS If the .Ar script cannot be found, the exit status will be 127; if it cannot be opened for another reason, the exit status will be 126. Other errors that are detected by the shell, such as a syntax error, will cause the shell to exit with a non-zero exit status. If the shell is not an interactive shell, the execution of the shell file will be aborted. Otherwise the shell will return the exit status of the last command executed, or if the .Ic exit builtin is used with a numeric argument, it will return the argument. .Sh SEE ALSO .Xr builtin 1 , .Xr chsh 1 , .Xr echo 1 , .Xr ed 1 , .Xr emacs 1 , .Xr kill 1 , .Xr printf 1 , .Xr pwd 1 , .Xr test 1 , .Xr vi 1 , .Xr execve 2 , .Xr getrlimit 2 , .Xr umask 2 , .Xr wctype 3 , .Xr editrc 5 , .Xr shells 5 .Sh HISTORY A .Nm command, the Thompson shell, appeared in .At v1 . It was superseded in .At v7 by the Bourne shell, which inherited the name .Nm . .Pp This version of .Nm was rewritten in 1989 under the .Bx license after the Bourne shell from .At V.4 . .Sh AUTHORS This version of .Nm was originally written by .An Kenneth Almquist . .Sh BUGS The .Nm utility does not recognize multibyte characters other than UTF-8. Splitting using .Va IFS does not recognize multibyte characters. diff --git a/bin/sh/trap.c b/bin/sh/trap.c index d7ef40274270..2dd394035ca4 100644 --- a/bin/sh/trap.c +++ b/bin/sh/trap.c @@ -1,550 +1,553 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint #if 0 static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95"; #endif #endif /* not lint */ #include __FBSDID("$FreeBSD$"); #include #include #include #include "shell.h" #include "main.h" #include "nodes.h" /* for other headers */ #include "eval.h" #include "jobs.h" #include "show.h" #include "options.h" #include "syntax.h" #include "output.h" #include "memalloc.h" #include "error.h" #include "trap.h" #include "mystring.h" #include "builtins.h" #include "myhistedit.h" /* * Sigmode records the current value of the signal handlers for the various * modes. A value of zero means that the current handler is not known. * S_HARD_IGN indicates that the signal was ignored on entry to the shell, */ #define S_DFL 1 /* default signal handling (SIG_DFL) */ #define S_CATCH 2 /* signal is caught */ #define S_IGN 3 /* signal is ignored (SIG_IGN) */ #define S_HARD_IGN 4 /* signal is ignored permanently */ #define S_RESET 5 /* temporary - to reset a hard ignored sig */ static char sigmode[NSIG]; /* current value of signal */ volatile sig_atomic_t pendingsig; /* indicates some signal received */ volatile sig_atomic_t pendingsig_waitcmd; /* indicates wait builtin should be interrupted */ static int in_dotrap; /* do we execute in a trap handler? */ static char *volatile trap[NSIG]; /* trap handler commands */ static volatile sig_atomic_t gotsig[NSIG]; /* indicates specified signal received */ static int ignore_sigchld; /* Used while handling SIGCHLD traps. */ static int last_trapsig; static int exiting; /* exitshell() has been called */ static int exiting_exitstatus; /* value passed to exitshell() */ static int getsigaction(int, sig_t *); /* * Map a string to a signal number. * * Note: the signal number may exceed NSIG. */ static int sigstring_to_signum(char *sig) { if (is_number(sig)) { int signo; signo = atoi(sig); return ((signo >= 0 && signo < NSIG) ? signo : (-1)); } else if (strcasecmp(sig, "EXIT") == 0) { return (0); } else { int n; if (strncasecmp(sig, "SIG", 3) == 0) sig += 3; for (n = 1; n < sys_nsig; n++) if (sys_signame[n] && strcasecmp(sys_signame[n], sig) == 0) return (n); } return (-1); } /* * Print a list of valid signal names. */ static void printsignals(void) { int n, outlen; outlen = 0; for (n = 1; n < sys_nsig; n++) { if (sys_signame[n]) { out1fmt("%s", sys_signame[n]); outlen += strlen(sys_signame[n]); } else { out1fmt("%d", n); outlen += 3; /* good enough */ } ++outlen; if (outlen > 71 || n == sys_nsig - 1) { out1str("\n"); outlen = 0; } else { out1c(' '); } } } /* * The trap builtin. */ int trapcmd(int argc __unused, char **argv) { char *action; int signo; int errors = 0; int i; while ((i = nextopt("l")) != '\0') { switch (i) { case 'l': printsignals(); return (0); } } argv = argptr; if (*argv == NULL) { for (signo = 0 ; signo < sys_nsig ; signo++) { if (signo < NSIG && trap[signo] != NULL) { out1str("trap -- "); out1qstr(trap[signo]); if (signo == 0) { out1str(" EXIT\n"); } else if (sys_signame[signo]) { out1fmt(" %s\n", sys_signame[signo]); } else { out1fmt(" %d\n", signo); } } } return 0; } action = NULL; if (*argv && !is_number(*argv)) { if (strcmp(*argv, "-") == 0) argv++; else { action = *argv; argv++; } } for (; *argv; argv++) { if ((signo = sigstring_to_signum(*argv)) == -1) { warning("bad signal %s", *argv); errors = 1; continue; } INTOFF; if (action) action = savestr(action); if (trap[signo]) ckfree(trap[signo]); trap[signo] = action; if (signo != 0) setsignal(signo); INTON; } return errors; } /* * Clear traps on a fork. */ void clear_traps(void) { char *volatile *tp; for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) { if (*tp && **tp) { /* trap not NULL or SIG_IGN */ INTOFF; ckfree(*tp); *tp = NULL; if (tp != &trap[0]) setsignal(tp - trap); INTON; } } } /* * Check if we have any traps enabled. */ int have_traps(void) { char *volatile *tp; for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) { if (*tp && **tp) /* trap not NULL or SIG_IGN */ return 1; } return 0; } /* * Set the signal handler for the specified signal. The routine figures * out what it should be set to. */ void setsignal(int signo) { int action; sig_t sigact = SIG_DFL; struct sigaction sa; char *t; if ((t = trap[signo]) == NULL) action = S_DFL; else if (*t != '\0') action = S_CATCH; else action = S_IGN; if (action == S_DFL) { switch (signo) { case SIGINT: action = S_CATCH; break; case SIGQUIT: #ifdef DEBUG if (debug) break; #endif action = S_CATCH; break; case SIGTERM: if (rootshell && iflag) action = S_IGN; break; #if JOBS case SIGTSTP: case SIGTTOU: if (rootshell && mflag) action = S_IGN; break; #endif } } t = &sigmode[signo]; if (*t == 0) { /* * current setting unknown */ if (!getsigaction(signo, &sigact)) { /* * Pretend it worked; maybe we should give a warning * here, but other shells don't. We don't alter * sigmode, so that we retry every time. */ return; } if (sigact == SIG_IGN) { if (mflag && (signo == SIGTSTP || signo == SIGTTIN || signo == SIGTTOU)) { *t = S_IGN; /* don't hard ignore these */ } else *t = S_HARD_IGN; } else { *t = S_RESET; /* force to be set */ } } if (*t == S_HARD_IGN || *t == action) return; switch (action) { case S_DFL: sigact = SIG_DFL; break; case S_CATCH: sigact = onsig; break; case S_IGN: sigact = SIG_IGN; break; } *t = action; sa.sa_handler = sigact; sa.sa_flags = 0; sigemptyset(&sa.sa_mask); sigaction(signo, &sa, NULL); } /* * Return the current setting for sig w/o changing it. */ static int getsigaction(int signo, sig_t *sigact) { struct sigaction sa; if (sigaction(signo, (struct sigaction *)0, &sa) == -1) return 0; *sigact = (sig_t) sa.sa_handler; return 1; } /* * Ignore a signal. */ void ignoresig(int signo) { if (sigmode[signo] == 0) setsignal(signo); if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) { signal(signo, SIG_IGN); sigmode[signo] = S_IGN; } } int issigchldtrapped(void) { return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0'); } /* * Signal handler. */ void onsig(int signo) { if (signo == SIGINT && trap[SIGINT] == NULL) { if (suppressint) SET_PENDING_INT; else onint(); return; } /* If we are currently in a wait builtin, prepare to break it */ if (signo == SIGINT || signo == SIGQUIT) pendingsig_waitcmd = signo; if (trap[signo] != NULL && trap[signo][0] != '\0' && (signo != SIGCHLD || !ignore_sigchld)) { gotsig[signo] = 1; pendingsig = signo; pendingsig_waitcmd = signo; } } /* * Called to execute a trap. Perhaps we should avoid entering new trap * handlers while we are executing a trap handler. */ void dotrap(void) { struct stackmark smark; int i; int savestatus, prev_evalskip, prev_skipcount; in_dotrap++; for (;;) { pendingsig = 0; pendingsig_waitcmd = 0; for (i = 1; i < NSIG; i++) { if (gotsig[i]) { gotsig[i] = 0; if (trap[i]) { /* * Ignore SIGCHLD to avoid infinite * recursion if the trap action does * a fork. */ if (i == SIGCHLD) ignore_sigchld++; /* * Backup current evalskip * state and reset it before * executing a trap, so that the * trap is not disturbed by an * ongoing break/continue/return * statement. */ prev_evalskip = evalskip; prev_skipcount = skipcount; evalskip = 0; last_trapsig = i; savestatus = exitstatus; setstackmark(&smark); evalstring(stsavestr(trap[i]), 0); popstackmark(&smark); /* * If such a command was not * already in progress, allow a * break/continue/return in the * trap action to have an effect * outside of it. */ if (evalskip == 0 || prev_evalskip != 0) { evalskip = prev_evalskip; skipcount = prev_skipcount; exitstatus = savestatus; } if (i == SIGCHLD) ignore_sigchld--; } break; } } if (i >= NSIG) break; } in_dotrap--; } void trap_init(void) { setsignal(SIGINT); setsignal(SIGQUIT); } /* * Controls whether the shell is interactive or not based on iflag. */ void setinteractive(void) { setsignal(SIGTERM); } /* * Called to exit the shell. */ void exitshell(int status) { TRACE(("exitshell(%d) pid=%d\n", status, getpid())); exiting = 1; exiting_exitstatus = status; exitshell_savedstatus(); } void exitshell_savedstatus(void) { struct jmploc loc1, loc2; char *p; int sig = 0; sigset_t sigs; if (!exiting) { if (in_dotrap && last_trapsig) { sig = last_trapsig; exiting_exitstatus = sig + 128; } else exiting_exitstatus = oexitstatus; } exitstatus = oexitstatus = exiting_exitstatus; if (!setjmp(loc1.loc)) { handler = &loc1; if ((p = trap[0]) != NULL && *p != '\0') { /* * Reset evalskip, or the trap on EXIT could be * interrupted if the last command was a "return". */ evalskip = 0; trap[0] = NULL; FORCEINTON; evalstring(p, 0); } } if (!setjmp(loc2.loc)) { handler = &loc2; /* probably unnecessary */ FORCEINTON; flushall(); #if JOBS setjobctl(0); +#endif +#ifndef NO_HISTORY + histsave(); #endif } if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN && sig != SIGTTOU) { signal(sig, SIG_DFL); sigemptyset(&sigs); sigaddset(&sigs, sig); sigprocmask(SIG_UNBLOCK, &sigs, NULL); kill(getpid(), sig); /* If the default action is to ignore, fall back to _exit(). */ } _exit(exiting_exitstatus); }