Index: head/usr.bin/xargs/xargs.1 =================================================================== --- head/usr.bin/xargs/xargs.1 (revision 365953) +++ head/usr.bin/xargs/xargs.1 (revision 365954) @@ -1,391 +1,391 @@ .\" Copyright (c) 1990, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" John B. Roll Jr. and the Institute of Electrical and Electronics .\" Engineers, Inc. .\" .\" 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. .\" .\" @(#)xargs.1 8.1 (Berkeley) 6/6/93 .\" $FreeBSD$ .\" $xMach: xargs.1,v 1.2 2002/02/23 05:23:37 tim Exp $ .\" -.Dd June 11, 2020 +.Dd September 21, 2020 .Dt XARGS 1 .Os .Sh NAME .Nm xargs .Nd "construct argument list(s) and execute utility" .Sh SYNOPSIS .Nm .Op Fl 0oprt .Op Fl E Ar eofstr .Oo .Fl I Ar replstr .Op Fl R Ar replacements .Op Fl S Ar replsize .Oc .Op Fl J Ar replstr .Op Fl L Ar number .Oo .Fl n Ar number .Op Fl x .Oc .Op Fl P Ar maxprocs .Op Fl s Ar size .Op Ar utility Op Ar argument ... .Sh DESCRIPTION The .Nm utility reads space, tab, newline and end-of-file delimited strings from the standard input and executes .Ar utility with the strings as arguments. .Pp Any arguments specified on the command line are given to .Ar utility upon each invocation, followed by some number of the arguments read from the standard input of .Nm . This is repeated until standard input is exhausted. .Pp Spaces, tabs and newlines may be embedded in arguments using single (``\ '\ '') or double (``"'') quotes or backslashes (``\e''). Single quotes escape all non-single quote characters, excluding newlines, up to the matching single quote. Double quotes escape all non-double quote characters, excluding newlines, up to the matching double quote. Any single character, including newlines, may be escaped by a backslash. .Pp The options are as follows: .Bl -tag -width indent -.It Fl 0 +.It Fl 0 , Fl -null Change .Nm to expect NUL (``\\0'') characters as separators, instead of spaces and newlines. This is expected to be used in concert with the .Fl print0 function in .Xr find 1 . .It Fl E Ar eofstr Use .Ar eofstr as a logical EOF marker. .It Fl I Ar replstr Execute .Ar utility for each input line, replacing one or more occurrences of .Ar replstr in up to .Ar replacements (or 5 if no .Fl R flag is specified) arguments to .Ar utility with the entire line of input. The resulting arguments, after replacement is done, will not be allowed to grow beyond .Ar replsize (or 255 if no .Fl S flag is specified) bytes; this is implemented by concatenating as much of the argument containing .Ar replstr as possible, to the constructed arguments to .Ar utility , up to .Ar replsize bytes. The size limit does not apply to arguments to .Ar utility which do not contain .Ar replstr , and furthermore, no replacement will be done on .Ar utility itself. Implies .Fl x . .It Fl J Ar replstr If this option is specified, .Nm will use the data read from standard input to replace the first occurrence of .Ar replstr instead of appending that data after all other arguments. This option will not affect how many arguments will be read from input .Pq Fl n , or the size of the command(s) .Nm will generate .Pq Fl s . The option just moves where those arguments will be placed in the command(s) that are executed. The .Ar replstr must show up as a distinct .Ar argument to .Nm . It will not be recognized if, for instance, it is in the middle of a quoted string. Furthermore, only the first occurrence of the .Ar replstr will be replaced. For example, the following command will copy the list of files and directories which start with an uppercase letter in the current directory to .Pa destdir : .Pp .Dl /bin/ls -1d [A-Z]* | xargs -J % cp -Rp % destdir .It Fl L Ar number Call .Ar utility for every .Ar number lines read. If EOF is reached and fewer lines have been read than .Ar number then .Ar utility will be called with the available lines. -.It Fl n Ar number +.It Fl n Ar number , Fl -max-args= Ns Ar number Set the maximum number of arguments taken from standard input for each invocation of .Ar utility . An invocation of .Ar utility will use less than .Ar number standard input arguments if the number of bytes accumulated (see the .Fl s option) exceeds the specified .Ar size or there are fewer than .Ar number arguments remaining for the last invocation of .Ar utility . The current default value for .Ar number is 5000. .It Fl o Reopen stdin as .Pa /dev/tty in the child process before executing the command. This is useful if you want .Nm to run an interactive application. -.It Fl P Ar maxprocs +.It Fl P Ar maxprocs , Fl -max-procs= Ns Ar maxprocs Parallel mode: run at most .Ar maxprocs invocations of .Ar utility at once. If .Ar maxprocs is set to 0, .Nm will run as many processes as possible. -.It Fl p +.It Fl p , Fl -interactive Echo each command to be executed and ask the user whether it should be executed. An affirmative response, .Ql y in the POSIX locale, causes the command to be executed, any other response causes it to be skipped. No commands are executed if the process is not attached to a terminal. -.It Fl r +.It Fl r , Fl -no-run-if-empty Compatibility with GNU .Nm . The GNU version of .Nm runs the .Ar utility argument at least once, even if .Nm input is empty, and it supports a .Fl r option to inhibit this behavior. The .Fx version of .Nm does not run the .Ar utility argument on empty input, but it supports the .Fl r option for command-line compatibility with GNU .Nm , but the .Fl r option does nothing in the .Fx version of .Nm . .It Fl R Ar replacements Specify the maximum number of arguments that .Fl I will do replacement in. If .Ar replacements is negative, the number of arguments in which to replace is unbounded. .It Fl S Ar replsize Specify the amount of space (in bytes) that .Fl I can use for replacements. The default for .Ar replsize is 255. -.It Fl s Ar size +.It Fl s Ar size , Fl -max-chars= Ns Ar size Set the maximum number of bytes for the command line length provided to .Ar utility . The sum of the length of the utility name, the arguments passed to .Ar utility (including .Dv NULL terminators) and the current environment will be less than or equal to this number. The current default value for .Ar size is .Dv ARG_MAX - 4096. -.It Fl t +.It Fl t , Fl -verbose Echo the command to be executed to standard error immediately before it is executed. -.It Fl x +.It Fl x , Fl -exit Force .Nm to terminate immediately if a command line containing .Ar number arguments will not fit in the specified (or default) command line length. .El .Pp If .Ar utility is omitted, .Xr echo 1 is used. .Pp Undefined behavior may occur if .Ar utility reads from the standard input. .Pp If a command line cannot be assembled, or cannot be invoked, or if an invocation of .Ar utility is terminated by a signal, or an invocation of .Ar utility exits with a value of 255, the .Nm utility stops processing input and exits after all invocations of .Ar utility finish processing. .Sh EXIT STATUS The .Nm utility exits with a value of 0 if no error occurs. If .Ar utility cannot be found, .Nm exits with a value of 127, otherwise if .Ar utility cannot be executed, .Nm exits with a value of 126. If any other error occurs, .Nm exits with a value of 1. .Sh EXAMPLES Create a 3x3 matrix with numbers from 1 to 9. Every .Xr echo 1 instance receives three lines as arguments: .Bd -literal -offset indent $ seq 1 9 | xargs -L3 echo 1 2 3 4 5 6 7 8 9 .Ed .Pp Duplicate every line from standard input: .Bd -literal -offset indent $ echo -e "one\\ntwo\\nthree" | xargs -I % echo % % one one two two three three .Ed .Pp Execute at most 2 concurrent instances of .Xr find 1 every one of them using one of the directories from the standard input: .Bd -literal -offset indent echo -e "/usr/ports\\n/etc\\n/usr/local" | xargs -J % -P2 -n1 find % -name file .Ed .Sh SEE ALSO .Xr echo 1 , .Xr find 1 , .Xr execvp 3 .Sh STANDARDS The .Nm utility is expected to be .St -p1003.2 compliant. The .Fl J , o , P , R and .Fl S options are non-standard .Fx extensions which may not be available on other operating systems. .Sh HISTORY The .Nm utility appeared in PWB UNIX. .Sh BUGS If .Ar utility attempts to invoke another command such that the number of arguments or the size of the environment is increased, it risks .Xr execvp 3 failing with .Er E2BIG . .Pp The .Nm utility does not take multibyte characters into account when performing string comparisons for the .Fl I and .Fl J options, which may lead to incorrect results in some locales. Index: head/usr.bin/xargs/xargs.c =================================================================== --- head/usr.bin/xargs/xargs.c (revision 365953) +++ head/usr.bin/xargs/xargs.c (revision 365954) @@ -1,788 +1,805 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * John B. Roll Jr. * * 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. * * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $ */ #if 0 #ifndef lint static const char copyright[] = "@(#) Copyright (c) 1990, 1993\n\ The Regents of the University of California. All rights reserved.\n"; #endif /* not lint */ #ifndef lint static char sccsid[] = "@(#)xargs.c 8.1 (Berkeley) 6/6/93"; #endif /* not lint */ #endif #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include +#include #include #include #include #include #include #include #include #include #include "pathnames.h" static void parse_input(int, char *[]); static void prerun(int, char *[]); static int prompt(void); static void run(char **); static void usage(void); void strnsubst(char **, const char *, const char *, size_t); static pid_t xwait(int block, int *status); static void xexit(const char *, const int); static void waitchildren(const char *, int); static void pids_init(void); static int pids_empty(void); static int pids_full(void); static void pids_add(pid_t pid); static int pids_remove(pid_t pid); static int findslot(pid_t pid); static int findfreeslot(void); static void clearslot(int slot); static char echo[] = _PATH_ECHO; static char **av, **bxp, **ep, **endxp, **xp; static char *argp, *bbp, *ebp, *inpline, *p, *replstr; static const char *eofstr; static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag; static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag; static int curprocs, maxprocs; static pid_t *childpids; static volatile int childerr; extern char **environ; +static const char *optstr = "+0E:I:J:L:n:oP:pR:S:s:rtx"; + +static const struct option long_options[] = +{ + {"exit", no_argument, NULL, 'x'}, + {"interactive", no_argument, NULL, 'p'}, + {"max-args", required_argument, NULL, 'n'}, + {"max-chars", required_argument, NULL, 's'}, + {"max-procs", required_argument, NULL, 'P'}, + {"no-run-if-empty", no_argument, NULL, 'r'}, + {"null", no_argument, NULL, '0'}, + {"verbose", no_argument, NULL, 't'}, + + {NULL, no_argument, NULL, 0}, +}; + int main(int argc, char *argv[]) { long arg_max; int ch, Jflag, nargs, nflag, nline; size_t linelen; struct rlimit rl; char *endptr; const char *errstr; inpline = replstr = NULL; ep = environ; eofstr = ""; Jflag = nflag = 0; (void)setlocale(LC_ALL, ""); /* * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given * that the smallest argument is 2 bytes in length, this means that * the number of arguments is limited to: * * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2. * * We arbitrarily limit the number of arguments to 5000. This is * allowed by POSIX.2 as long as the resulting minimum exec line is * at least LINE_MAX. Realloc'ing as necessary is possible, but * probably not worthwhile. */ nargs = 5000; if ((arg_max = sysconf(_SC_ARG_MAX)) == -1) errx(1, "sysconf(_SC_ARG_MAX) failed"); nline = arg_max - 4 * 1024; while (*ep != NULL) { /* 1 byte for each '\0' */ nline -= strlen(*ep++) + 1 + sizeof(*ep); } maxprocs = 1; - while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:S:s:rtx")) != -1) + while ((ch = getopt_long(argc, argv, optstr, long_options, NULL)) != -1) switch (ch) { case 'E': eofstr = optarg; break; case 'I': Jflag = 0; Iflag = 1; Lflag = 1; replstr = optarg; break; case 'J': Iflag = 0; Jflag = 1; replstr = optarg; break; case 'L': Lflag = strtonum(optarg, 0, INT_MAX, &errstr); if (errstr) errx(1, "-L %s: %s", optarg, errstr); break; case 'n': nflag = 1; nargs = strtonum(optarg, 1, INT_MAX, &errstr); if (errstr) errx(1, "-n %s: %s", optarg, errstr); break; case 'o': oflag = 1; break; case 'P': maxprocs = strtonum(optarg, 0, INT_MAX, &errstr); if (errstr) errx(1, "-P %s: %s", optarg, errstr); if (getrlimit(RLIMIT_NPROC, &rl) != 0) errx(1, "getrlimit failed"); if (maxprocs == 0 || maxprocs > rl.rlim_cur) maxprocs = rl.rlim_cur; break; case 'p': pflag = 1; break; case 'R': Rflag = strtol(optarg, &endptr, 10); if (*endptr != '\0') errx(1, "replacements must be a number"); break; case 'r': /* GNU compatibility */ break; case 'S': Sflag = strtoul(optarg, &endptr, 10); if (*endptr != '\0') errx(1, "replsize must be a number"); break; case 's': nline = strtonum(optarg, 0, INT_MAX, &errstr); if (errstr) errx(1, "-s %s: %s", optarg, errstr); break; case 't': tflag = 1; break; case 'x': xflag = 1; break; case '0': zflag = 1; break; case '?': default: usage(); } argc -= optind; argv += optind; if (!Iflag && Rflag) usage(); if (!Iflag && Sflag) usage(); if (Iflag && !Rflag) Rflag = 5; if (Iflag && !Sflag) Sflag = 255; if (xflag && !nflag) usage(); if (Iflag || Lflag) xflag = 1; if (replstr != NULL && *replstr == '\0') errx(1, "replstr may not be empty"); pids_init(); /* * Allocate pointers for the utility name, the utility arguments, * the maximum arguments to be read from stdin and the trailing * NULL. */ linelen = 1 + argc + nargs + 1; if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL) errx(1, "malloc failed"); /* * Use the user's name for the utility as argv[0], just like the * shell. Echo is the default. Set up pointers for the user's * arguments. */ if (*argv == NULL) cnt = strlen(*bxp++ = echo); else { do { if (Jflag && strcmp(*argv, replstr) == 0) { char **avj; jfound = 1; argv++; for (avj = argv; *avj; avj++) cnt += strlen(*avj) + 1; break; } cnt += strlen(*bxp++ = *argv) + 1; } while (*++argv != NULL); } /* * Set up begin/end/traversing pointers into the array. The -n * count doesn't include the trailing NULL pointer, so the malloc * added in an extra slot. */ endxp = (xp = bxp) + nargs; /* * Allocate buffer space for the arguments read from stdin and the * trailing NULL. Buffer space is defined as the default or specified * space, minus the length of the utility name and arguments. Set up * begin/end/traversing pointers into the array. The -s count does * include the trailing NULL, so the malloc didn't add in an extra * slot. */ nline -= cnt; if (nline <= 0) errx(1, "insufficient space for command"); if ((bbp = malloc((size_t)(nline + 1))) == NULL) errx(1, "malloc failed"); ebp = (argp = p = bbp) + nline - 1; for (;;) parse_input(argc, argv); } static void parse_input(int argc, char *argv[]) { int ch, foundeof; char **avj; foundeof = 0; switch (ch = getchar()) { case EOF: /* No arguments since last exec. */ if (p == bbp) xexit(*av, rval); goto arg1; case ' ': case '\t': /* Quotes escape tabs and spaces. */ if (insingle || indouble || zflag) goto addch; goto arg2; case '\0': if (zflag) { /* * Increment 'count', so that nulls will be treated * as end-of-line, as well as end-of-argument. This * is needed so -0 works properly with -I and -L. */ count++; goto arg2; } goto addch; case '\n': if (zflag) goto addch; count++; /* Indicate end-of-line (used by -L) */ /* Quotes do not escape newlines. */ arg1: if (insingle || indouble) { warnx("unterminated quote"); xexit(*av, 1); } arg2: foundeof = *eofstr != '\0' && strncmp(argp, eofstr, p - argp) == 0; /* Do not make empty args unless they are quoted */ if ((argp != p || wasquoted) && !foundeof) { *p++ = '\0'; *xp++ = argp; if (Iflag) { size_t curlen; if (inpline == NULL) curlen = 0; else { /* * If this string is not zero * length, append a space for * separation before the next * argument. */ if ((curlen = strlen(inpline))) strcat(inpline, " "); } curlen++; /* * Allocate enough to hold what we will * be holding in a second, and to append * a space next time through, if we have * to. */ inpline = realloc(inpline, curlen + 2 + strlen(argp)); if (inpline == NULL) { warnx("realloc failed"); xexit(*av, 1); } if (curlen == 1) strcpy(inpline, argp); else strcat(inpline, argp); } } /* * If max'd out on args or buffer, or reached EOF, * run the command. If xflag and max'd out on buffer * but not on args, object. Having reached the limit * of input lines, as specified by -L is the same as * maxing out on arguments. */ if (xp == endxp || p > ebp || ch == EOF || (Lflag <= count && xflag) || foundeof) { if (xflag && xp != endxp && p > ebp) { warnx("insufficient space for arguments"); xexit(*av, 1); } if (jfound) { for (avj = argv; *avj; avj++) *xp++ = *avj; } prerun(argc, av); if (ch == EOF || foundeof) xexit(*av, rval); p = bbp; xp = bxp; count = 0; } argp = p; wasquoted = 0; break; case '\'': if (indouble || zflag) goto addch; insingle = !insingle; wasquoted = 1; break; case '"': if (insingle || zflag) goto addch; indouble = !indouble; wasquoted = 1; break; case '\\': if (zflag) goto addch; /* Backslash escapes anything, is escaped by quotes. */ if (!insingle && !indouble && (ch = getchar()) == EOF) { warnx("backslash at EOF"); xexit(*av, 1); } /* FALLTHROUGH */ default: addch: if (p < ebp) { *p++ = ch; break; } /* If only one argument, not enough buffer space. */ if (bxp == xp) { warnx("insufficient space for argument"); xexit(*av, 1); } /* Didn't hit argument limit, so if xflag object. */ if (xflag) { warnx("insufficient space for arguments"); xexit(*av, 1); } if (jfound) { for (avj = argv; *avj; avj++) *xp++ = *avj; } prerun(argc, av); xp = bxp; cnt = ebp - argp; memcpy(bbp, argp, (size_t)cnt); p = (argp = bbp) + cnt; *p++ = ch; break; } } /* * Do things necessary before run()'ing, such as -I substitution, * and then call run(). */ static void prerun(int argc, char *argv[]) { char **tmp, **tmp2, **avj; int repls; repls = Rflag; if (argc == 0 || repls == 0) { *xp = NULL; run(argv); return; } avj = argv; /* * Allocate memory to hold the argument list, and * a NULL at the tail. */ tmp = malloc((argc + 1) * sizeof(char *)); if (tmp == NULL) { warnx("malloc failed"); xexit(*argv, 1); } tmp2 = tmp; /* * Save the first argument and iterate over it, we * cannot do strnsubst() to it. */ if ((*tmp++ = strdup(*avj++)) == NULL) { warnx("strdup failed"); xexit(*argv, 1); } /* * For each argument to utility, if we have not used up * the number of replacements we are allowed to do, and * if the argument contains at least one occurrence of * replstr, call strnsubst(), else just save the string. * Iterations over elements of avj and tmp are done * where appropriate. */ while (--argc) { *tmp = *avj++; if (repls && strstr(*tmp, replstr) != NULL) { strnsubst(tmp++, replstr, inpline, (size_t)Sflag); if (repls > 0) repls--; } else { if ((*tmp = strdup(*tmp)) == NULL) { warnx("strdup failed"); xexit(*argv, 1); } tmp++; } } /* * Run it. */ *tmp = NULL; run(tmp2); /* * Walk from the tail to the head, free along the way. */ for (; tmp2 != tmp; tmp--) free(*tmp); /* * Now free the list itself. */ free(tmp2); /* * Free the input line buffer, if we have one. */ if (inpline != NULL) { free(inpline); inpline = NULL; } } static void run(char **argv) { pid_t pid; int fd; char **avec; /* * If the user wants to be notified of each command before it is * executed, notify them. If they want the notification to be * followed by a prompt, then prompt them. */ if (tflag || pflag) { (void)fprintf(stderr, "%s", *argv); for (avec = argv + 1; *avec != NULL; ++avec) (void)fprintf(stderr, " %s", *avec); /* * If the user has asked to be prompted, do so. */ if (pflag) /* * If they asked not to exec, return without execution * but if they asked to, go to the execution. If we * could not open their tty, break the switch and drop * back to -t behaviour. */ switch (prompt()) { case 0: return; case 1: goto exec; case 2: break; } (void)fprintf(stderr, "\n"); (void)fflush(stderr); } exec: childerr = 0; switch (pid = vfork()) { case -1: warn("vfork"); xexit(*argv, 1); case 0: if (oflag) { if ((fd = open(_PATH_TTY, O_RDONLY)) == -1) err(1, "can't open /dev/tty"); } else { fd = open(_PATH_DEVNULL, O_RDONLY); } if (fd > STDIN_FILENO) { if (dup2(fd, STDIN_FILENO) != 0) err(1, "can't dup2 to stdin"); close(fd); } execvp(argv[0], argv); childerr = errno; _exit(1); } pids_add(pid); waitchildren(*argv, 0); } /* * Wait for a tracked child to exit and return its pid and exit status. * * Ignores (discards) all untracked child processes. * Returns -1 and sets errno to ECHILD if no tracked children exist. * If block is set, waits indefinitely for a child process to exit. * If block is not set and no children have exited, returns 0 immediately. */ static pid_t xwait(int block, int *status) { pid_t pid; if (pids_empty()) { errno = ECHILD; return (-1); } while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0) if (pids_remove(pid)) break; return (pid); } static void xexit(const char *name, const int exit_code) { waitchildren(name, 1); exit(exit_code); } static void waitchildren(const char *name, int waitall) { pid_t pid; int status; int cause_exit = 0; while ((pid = xwait(waitall || pids_full(), &status)) > 0) { /* * If we couldn't invoke the utility or if utility exited * because of a signal or with a value of 255, warn (per * POSIX), and then wait until all other children have * exited before exiting 1-125. POSIX requires us to stop * reading if child exits because of a signal or with 255, * but it does not require us to exit immediately; waiting * is preferable to orphaning. */ if (childerr != 0 && cause_exit == 0) { errno = childerr; waitall = 1; cause_exit = errno == ENOENT ? 127 : 126; warn("%s", name); } else if (WIFSIGNALED(status)) { waitall = cause_exit = 1; warnx("%s: terminated with signal %d; aborting", name, WTERMSIG(status)); } else if (WEXITSTATUS(status) == 255) { waitall = cause_exit = 1; warnx("%s: exited with status 255; aborting", name); } else if (WEXITSTATUS(status)) rval = 1; } if (cause_exit) exit(cause_exit); if (pid == -1 && errno != ECHILD) err(1, "waitpid"); } #define NOPID (0) static void pids_init(void) { int i; if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL) errx(1, "malloc failed"); for (i = 0; i < maxprocs; i++) clearslot(i); } static int pids_empty(void) { return (curprocs == 0); } static int pids_full(void) { return (curprocs >= maxprocs); } static void pids_add(pid_t pid) { int slot; slot = findfreeslot(); childpids[slot] = pid; curprocs++; } static int pids_remove(pid_t pid) { int slot; if ((slot = findslot(pid)) < 0) return (0); clearslot(slot); curprocs--; return (1); } static int findfreeslot(void) { int slot; if ((slot = findslot(NOPID)) < 0) errx(1, "internal error: no free pid slot"); return (slot); } static int findslot(pid_t pid) { int slot; for (slot = 0; slot < maxprocs; slot++) if (childpids[slot] == pid) return (slot); return (-1); } static void clearslot(int slot) { childpids[slot] = NOPID; } /* * Prompt the user about running a command. */ static int prompt(void) { regex_t cre; size_t rsize; int match; char *response; FILE *ttyfp; if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL) return (2); /* Indicate that the TTY failed to open. */ (void)fprintf(stderr, "?..."); (void)fflush(stderr); if ((response = fgetln(ttyfp, &rsize)) == NULL || regcomp(&cre, nl_langinfo(YESEXPR), REG_BASIC) != 0) { (void)fclose(ttyfp); return (0); } response[rsize - 1] = '\0'; match = regexec(&cre, response, 0, NULL, 0); (void)fclose(ttyfp); regfree(&cre); return (match == 0); } static void usage(void) { fprintf(stderr, "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n" " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n" " [-s size] [utility [argument ...]]\n"); exit(1); }