diff --git a/usr.sbin/daemon/daemon.c b/usr.sbin/daemon/daemon.c index af387574c4b5..16e22efed68e 100644 --- a/usr.sbin/daemon/daemon.c +++ b/usr.sbin/daemon/daemon.c @@ -1,715 +1,720 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1999 Berkeley Software Design, Inc. 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. Berkeley Software Design Inc's name may not be used to endorse or * promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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 BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define SYSLOG_NAMES #include #include #include #define LBUF_SIZE 4096 struct log_params { const char *output_filename; const char *syslog_tag; int syslog_priority; int syslog_facility; int keep_fds_open; int output_fd; bool syslog_enabled; }; static void restrict_process(const char *); static void handle_term(int); static void handle_chld(int); static void handle_hup(int); static int open_log(const char *); static void reopen_log(struct log_params *); static int listen_child(int, struct log_params *); static int get_log_mapping(const char *, const CODE *); static void open_pid_files(const char *, const char *, struct pidfh **, struct pidfh **); static void do_output(const unsigned char *, size_t, struct log_params *); static void daemon_sleep(time_t, long); static volatile sig_atomic_t terminate = 0; static volatile sig_atomic_t child_gone = 0; static volatile sig_atomic_t pid = -1; static volatile sig_atomic_t do_log_reopen = 0; static const char shortopts[] = "+cfHSp:P:ru:o:s:l:t:m:R:T:h"; static const struct option longopts[] = { { "change-dir", no_argument, NULL, 'c' }, { "close-fds", no_argument, NULL, 'f' }, { "sighup", no_argument, NULL, 'H' }, { "syslog", no_argument, NULL, 'S' }, { "output-file", required_argument, NULL, 'o' }, { "output-mask", required_argument, NULL, 'm' }, { "child-pidfile", required_argument, NULL, 'p' }, { "supervisor-pidfile", required_argument, NULL, 'P' }, { "restart", no_argument, NULL, 'r' }, { "restart-delay", required_argument, NULL, 'R' }, { "title", required_argument, NULL, 't' }, { "user", required_argument, NULL, 'u' }, { "syslog-priority", required_argument, NULL, 's' }, { "syslog-facility", required_argument, NULL, 'l' }, { "syslog-tag", required_argument, NULL, 'T' }, { "help", no_argument, NULL, 'h' }, { NULL, 0, NULL, 0 } }; static _Noreturn void usage(int exitcode) { (void)fprintf(stderr, "usage: daemon [-cfHrS] [-p child_pidfile] [-P supervisor_pidfile]\n" " [-u user] [-o output_file] [-t title]\n" " [-l syslog_facility] [-s syslog_priority]\n" " [-T syslog_tag] [-m output_mask] [-R restart_delay_secs]\n" "command arguments ...\n"); (void)fprintf(stderr, " --change-dir -c Change the current working directory to root\n" " --close-fds -f Set stdin, stdout, stderr to /dev/null\n" " --sighup -H Close and re-open output file on SIGHUP\n" " --syslog -S Send output to syslog\n" " --output-file -o Append output of the child process to file\n" " --output-mask -m What to send to syslog/file\n" " 1=stdout, 2=stderr, 3=both\n" " --child-pidfile -p Write PID of the child process to file\n" " --supervisor-pidfile -P Write PID of the supervisor process to file\n" " --restart -r Restart child if it terminates (1 sec delay)\n" " --restart-delay -R Restart child if it terminates after N sec\n" " --title -t Set the title of the supervisor process\n" " --user -u <user> Drop privileges, run as given user\n" " --syslog-priority -s <prio> Set syslog priority\n" " --syslog-facility -l <flty> Set syslog facility\n" " --syslog-tag -T <tag> Set syslog tag\n" " --help -h Show this help\n"); - exit(exitcode); + exit(exitcode); } int main(int argc, char *argv[]) { bool supervision_enabled = false; bool log_reopen = false; char *p = NULL; const char *child_pidfile = NULL; const char *parent_pidfile = NULL; const char *title = NULL; const char *user = NULL; int ch = 0; int child_eof = 0; int keep_cur_workdir = 1; int pfd[2] = { -1, -1 }; int restart = 0; int stdmask = STDOUT_FILENO | STDERR_FILENO; struct log_params logparams = { .syslog_enabled = false, .syslog_priority = LOG_NOTICE, .syslog_tag = "daemon", .syslog_facility = LOG_DAEMON, .keep_fds_open = 1, .output_fd = -1, .output_filename = NULL - }; + }; struct pidfh *parent_pidfh = NULL; struct pidfh *child_pidfh = NULL; sigset_t mask_orig; sigset_t mask_read; sigset_t mask_term; sigset_t mask_susp; sigemptyset(&mask_susp); sigemptyset(&mask_read); sigemptyset(&mask_term); sigemptyset(&mask_orig); while ((ch = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1) { switch (ch) { case 'c': keep_cur_workdir = 0; break; case 'f': logparams.keep_fds_open = 0; break; case 'H': log_reopen = true; break; case 'l': - logparams.syslog_facility = get_log_mapping(optarg, facilitynames); + logparams.syslog_facility = get_log_mapping(optarg, + facilitynames); if (logparams.syslog_facility == -1) { errx(5, "unrecognized syslog facility"); - } + } logparams.syslog_enabled = true; break; case 'm': stdmask = strtol(optarg, &p, 10); if (p == optarg || stdmask < 0 || stdmask > 3) { errx(6, "unrecognized listening mask"); - } + } break; case 'o': logparams.output_filename = optarg; break; case 'p': child_pidfile = optarg; break; case 'P': parent_pidfile = optarg; break; case 'r': restart = 1; break; case 'R': restart = strtol(optarg, &p, 0); if (p == optarg || restart < 1) { errx(6, "invalid restart delay"); - } + } break; case 's': - logparams.syslog_priority = get_log_mapping(optarg, prioritynames); + logparams.syslog_priority = get_log_mapping(optarg, + prioritynames); if (logparams.syslog_priority == -1) { errx(4, "unrecognized syslog priority"); - } + } logparams.syslog_enabled = true; break; case 'S': logparams.syslog_enabled = true; break; case 't': title = optarg; break; case 'T': logparams.syslog_tag = optarg; logparams.syslog_enabled = true; break; case 'u': user = optarg; break; - case 'h': + case 'h': usage(0); - __builtin_unreachable(); + __builtin_unreachable(); default: usage(1); } } argc -= optind; argv += optind; if (argc == 0) { usage(1); - } + } if (!title) { title = argv[0]; - } + } if (logparams.output_filename) { logparams.output_fd = open_log(logparams.output_filename); if (logparams.output_fd == -1) { err(7, "open"); - } + } } if (logparams.syslog_enabled) { - openlog(logparams.syslog_tag, LOG_PID | LOG_NDELAY, logparams.syslog_facility); - } + openlog(logparams.syslog_tag, LOG_PID | LOG_NDELAY, + logparams.syslog_facility); + } /* * Try to open the pidfile before calling daemon(3), * to be able to report the error intelligently */ open_pid_files(child_pidfile, parent_pidfile, &child_pidfh, &parent_pidfh); if (daemon(keep_cur_workdir, logparams.keep_fds_open) == -1) { warn("daemon"); goto exit; } /* Write out parent pidfile if needed. */ pidfile_write(parent_pidfh); /* * Supervision mode is enabled if one of the following options are used: * --child-pidfile -p * --supervisor-pidfile -P * --restart -r / --restart-delay -R * --syslog -S * --syslog-facility -l * --syslog-priority -s * --syslog-tag -T * * In supervision mode daemon executes the command in a forked process * and observes the child by waiting for SIGCHILD. In supervision mode * daemon must never exit before the child, this is necessary to prevent * orphaning the child and leaving a stale pid file. * To achieve this daemon catches SIGTERM and * forwards it to the child, expecting to get SIGCHLD eventually. */ supervision_enabled = child_pidfile != NULL || parent_pidfile != NULL || restart != 0 || logparams.output_fd != -1 || logparams.syslog_enabled == true; if (supervision_enabled) { struct sigaction act_term = { 0 }; struct sigaction act_chld = { 0 }; struct sigaction act_hup = { 0 }; /* Avoid PID racing with SIGCHLD and SIGTERM. */ act_term.sa_handler = handle_term; sigemptyset(&act_term.sa_mask); sigaddset(&act_term.sa_mask, SIGCHLD); act_chld.sa_handler = handle_chld; sigemptyset(&act_chld.sa_mask); sigaddset(&act_chld.sa_mask, SIGTERM); act_hup.sa_handler = handle_hup; sigemptyset(&act_hup.sa_mask); /* Block these when avoiding racing before sigsuspend(). */ sigaddset(&mask_susp, SIGTERM); sigaddset(&mask_susp, SIGCHLD); /* Block SIGTERM when we lack a valid child PID. */ sigaddset(&mask_term, SIGTERM); /* * When reading, we wish to avoid SIGCHLD. SIGTERM * has to be caught, otherwise we'll be stuck until * the read() returns - if it returns. */ sigaddset(&mask_read, SIGCHLD); /* Block SIGTERM to avoid racing until we have forked. */ if (sigprocmask(SIG_BLOCK, &mask_term, &mask_orig)) { warn("sigprocmask"); goto exit; } if (sigaction(SIGTERM, &act_term, NULL) == -1) { warn("sigaction"); goto exit; } if (sigaction(SIGCHLD, &act_chld, NULL) == -1) { warn("sigaction"); goto exit; } /* * Try to protect against pageout kill. Ignore the * error, madvise(2) will fail only if a process does * not have superuser privileges. */ (void)madvise(NULL, 0, MADV_PROTECT); if (log_reopen && logparams.output_fd >= 0 && sigaction(SIGHUP, &act_hup, NULL) == -1) { warn("sigaction"); goto exit; } restart: if (pipe(pfd)) { err(1, "pipe"); - } + } /* * Spawn a child to exec the command. */ child_gone = 0; pid = fork(); if (pid == -1) { warn("fork"); goto exit; } else if (pid > 0) { /* * Unblock SIGTERM after we know we have a valid * child PID to signal. */ if (sigprocmask(SIG_UNBLOCK, &mask_term, NULL)) { warn("sigprocmask"); goto exit; } close(pfd[1]); pfd[1] = -1; } } if (pid <= 0) { /* Now that we are the child, write out the pid. */ pidfile_write(child_pidfh); if (user != NULL) { restrict_process(user); - } + } /* * When forking, the child gets the original sigmask, * and dup'd pipes. */ if (pid == 0) { close(pfd[0]); if (sigprocmask(SIG_SETMASK, &mask_orig, NULL)) { err(1, "sigprogmask"); - } + } if (stdmask & STDERR_FILENO) { if (dup2(pfd[1], STDERR_FILENO) == -1) { err(1, "dup2"); - } + } } if (stdmask & STDOUT_FILENO) { if (dup2(pfd[1], STDOUT_FILENO) == -1) { err(1, "dup2"); - } + } } if (pfd[1] != STDERR_FILENO && pfd[1] != STDOUT_FILENO) { close(pfd[1]); - } + } } execvp(argv[0], argv); /* * execvp() failed -- report the error. The child is * now running, so the exit status doesn't matter. */ err(1, "%s", argv[0]); } setproctitle("%s[%d]", title, (int)pid); /* * As we have closed the write end of pipe for parent process, * we might detect the child's exit by reading EOF. The child * might have closed its stdout and stderr, so we must wait for * the SIGCHLD to ensure that the process is actually gone. */ for (;;) { /* * We block SIGCHLD when listening, but SIGTERM we accept * so the read() won't block if we wish to depart. * * Upon receiving SIGTERM, we have several options after * sending the SIGTERM to our child: * - read until EOF * - read until EOF but only for a while * - bail immediately * * We go for the third, as otherwise we have no guarantee * that we won't block indefinitely if the child refuses * to depart. To handle the second option, a different * approach would be needed (procctl()?) */ if (child_gone && child_eof) { break; } else if (terminate) { goto exit; } else if (!child_eof) { if (sigprocmask(SIG_BLOCK, &mask_read, NULL)) { warn("sigprocmask"); goto exit; } child_eof = !listen_child(pfd[0], &logparams); if (sigprocmask(SIG_UNBLOCK, &mask_read, NULL)) { warn("sigprocmask"); goto exit; } } else { if (sigprocmask(SIG_BLOCK, &mask_susp, NULL)) { warn("sigprocmask"); goto exit; } while (!terminate && !child_gone) sigsuspend(&mask_orig); if (sigprocmask(SIG_UNBLOCK, &mask_susp, NULL)) { warn("sigprocmask"); goto exit; } } } if (restart && !terminate) { daemon_sleep(restart, 0); - } + } if (sigprocmask(SIG_BLOCK, &mask_term, NULL)) { warn("sigprocmask"); goto exit; } if (restart && !terminate) { close(pfd[0]); pfd[0] = -1; goto restart; } exit: close(logparams.output_fd); close(pfd[0]); close(pfd[1]); if (logparams.syslog_enabled) { closelog(); - } + } pidfile_remove(child_pidfh); pidfile_remove(parent_pidfh); exit(1); /* If daemon(3) succeeded exit status does not matter. */ } static void daemon_sleep(time_t secs, long nsecs) { struct timespec ts = { secs, nsecs }; while (!terminate && nanosleep(&ts, &ts) == -1) { if (errno != EINTR) { err(1, "nanosleep"); - } + } } } static void open_pid_files(const char *pidfile, const char *ppidfile, struct pidfh **pfh, struct pidfh **ppfh) { pid_t fpid; int serrno; if (pidfile) { *pfh = pidfile_open(pidfile, 0600, &fpid); if (*pfh == NULL) { if (errno == EEXIST) { errx(3, "process already running, pid: %d", fpid); } err(2, "pidfile ``%s''", pidfile); } } /* Do the same for the actual daemon process. */ if (ppidfile) { *ppfh = pidfile_open(ppidfile, 0600, &fpid); if (*ppfh == NULL) { serrno = errno; pidfile_remove(*pfh); errno = serrno; if (errno == EEXIST) { errx(3, "process already running, pid: %d", fpid); } err(2, "ppidfile ``%s''", ppidfile); } } } static int get_log_mapping(const char *str, const CODE *c) { const CODE *cp; for (cp = c; cp->c_name; cp++) if (strcmp(cp->c_name, str) == 0) { return cp->c_val; - } + } return -1; } static void restrict_process(const char *user) { struct passwd *pw = NULL; pw = getpwnam(user); if (pw == NULL) { errx(1, "unknown user: %s", user); - } + } if (setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0) { errx(1, "failed to set user environment"); - } + } setenv("USER", pw->pw_name, 1); setenv("HOME", pw->pw_dir, 1); setenv("SHELL", *pw->pw_shell ? pw->pw_shell : _PATH_BSHELL, 1); } /* * We try to collect whole lines terminated by '\n'. Otherwise we collect a * full buffer, and then output it. * * Return value of 0 is assumed to mean EOF or error, and 1 indicates to * continue reading. */ static int listen_child(int fd, struct log_params *logpar) { static unsigned char buf[LBUF_SIZE]; static size_t bytes_read = 0; int rv; assert(logpar); assert(bytes_read < LBUF_SIZE - 1); if (do_log_reopen) { reopen_log(logpar); - } + } rv = read(fd, buf + bytes_read, LBUF_SIZE - bytes_read - 1); if (rv > 0) { unsigned char *cp; bytes_read += rv; assert(bytes_read <= LBUF_SIZE - 1); /* Always NUL-terminate just in case. */ buf[LBUF_SIZE - 1] = '\0'; /* * Chomp line by line until we run out of buffer. * This does not take NUL characters into account. */ while ((cp = memchr(buf, '\n', bytes_read)) != NULL) { size_t bytes_line = cp - buf + 1; assert(bytes_line <= bytes_read); do_output(buf, bytes_line, logpar); bytes_read -= bytes_line; memmove(buf, cp + 1, bytes_read); } /* Wait until the buffer is full. */ if (bytes_read < LBUF_SIZE - 1) { return 1; - } + } do_output(buf, bytes_read, logpar); bytes_read = 0; return 1; } else if (rv == -1) { /* EINTR should trigger another read. */ if (errno == EINTR) { return 1; } else { warn("read"); return 0; } } /* Upon EOF, we have to flush what's left of the buffer. */ if (bytes_read > 0) { do_output(buf, bytes_read, logpar); bytes_read = 0; } return 0; } /* * The default behavior is to stay silent if the user wants to redirect * output to a file and/or syslog. If neither are provided, then we bounce * everything back to parent's stdout. */ static void do_output(const unsigned char *buf, size_t len, struct log_params *logpar) { assert(len <= LBUF_SIZE); assert(logpar); if (len < 1) { return; - } + } if (logpar->syslog_enabled) { syslog(logpar->syslog_priority, "%.*s", (int)len, buf); - } + } if (logpar->output_fd != -1) { if (write(logpar->output_fd, buf, len) == -1) warn("write"); } - if (logpar->keep_fds_open && !logpar->syslog_enabled && logpar->output_fd == -1) { + if (logpar->keep_fds_open && + !logpar->syslog_enabled && + logpar->output_fd == -1) { printf("%.*s", (int)len, buf); - } + } } /* * We use the global PID acquired directly from fork. If there is no valid * child pid, the handler should be blocked and/or child_gone == 1. */ static void handle_term(int signo) { if (pid > 0 && !child_gone) { kill(pid, signo); - } + } terminate = 1; } static void handle_chld(int signo __unused) { for (;;) { int rv = waitpid(-1, NULL, WNOHANG); if (pid == rv) { child_gone = 1; break; } else if (rv == -1 && errno != EINTR) { warn("waitpid"); return; } } } static void handle_hup(int signo __unused) { do_log_reopen = 1; } static int open_log(const char *outfn) { return open(outfn, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0600); } static void reopen_log(struct log_params *logparams) { int outfd; do_log_reopen = 0; outfd = open_log(logparams->output_filename); if (logparams->output_fd >= 0) { close(logparams->output_fd); - } + } logparams->output_fd = outfd; }