dd a new option (-H) to daemon(8) to catch SIGHUP and re-open output_file file when
received. The default system log rotation mechanism (newsyslog(8)) requires ability to send signal to a daemon in order to properly complete rotation of the logs in an "atomic" manner without having to making a copy and truncating original file. Unfortunately our built-in mechanism to convert "dumb" programs into daemons has no way to handle this rotation properly. This change adds this ability, to be enabled by supplying -H option in addition to the -o option. Reviewed by: markj, rpokala (manpages) MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D26526
This commit is contained in:
Maxim Sobolev
parent
4d1bad3c62
commit
4cd407ec93
@ -26,7 +26,7 @@
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.\"
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.\" $FreeBSD$
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.\"
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.Dd October 2, 2019
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.Dd September 22, 2020
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.Dt DAEMON 8
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.Os
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.Sh NAME
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@ -34,7 +34,7 @@
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.Nd run detached from the controlling terminal
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.Sh SYNOPSIS
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.Nm
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.Op Fl cfrS
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.Op Fl cfHrS
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.Op Fl p Ar child_pidfile
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.Op Fl P Ar supervisor_pidfile
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.Op Fl t Ar title
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@ -68,6 +68,14 @@ or syslog output, the standard file descriptors are first redirected to
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.Pa /dev/null ,
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then stdout and/or stderr is redirected to a file or to syslog as
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specified by the other options.
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.It Fl H
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Close
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.Pa output_file
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and re-open it when signal SIGHUP is received, for interoperability with
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.Xr newsyslog 1
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and similar log rotation / archival mechanisms. If
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.Fa o
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is not specified, this flag is ignored.
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.It Fl S
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Enable syslog output.
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This is implicitly applied if other syslog parameters are provided.
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@ -77,6 +85,12 @@ tag, respectively.
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Append output from the daemonized process to
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.Pa output_file .
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If the file does not exist, it is created with permissions 0600.
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When this option is used together with options
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.Fl c and
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.Fl H
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the absolute path needs to be provided to ensure
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.Nm
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can re-open the file after a SIGHUP.
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.It Fl m Ar output_mask
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Redirect output from the child process stdout (1), stderr (2), or both (3).
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This value specifies what is sent to syslog and the log file.
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@ -61,11 +61,15 @@ struct log_params {
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int logpri;
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int noclose;
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int outfd;
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const char *outfn;
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};
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static void restrict_process(const char *);
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static void handle_term(int);
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static void handle_chld(int);
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static void handle_hup(int);
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static int open_log(const char *);
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static void reopen_log(struct log_params *);
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static int listen_child(int, struct log_params *);
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static int get_log_mapping(const char *, const CODE *);
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static void open_pid_files(const char *, const char *, struct pidfh **,
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@ -74,7 +78,8 @@ static void do_output(const unsigned char *, size_t, struct log_params *);
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static void daemon_sleep(time_t, long);
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static void usage(void);
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static volatile sig_atomic_t terminate = 0, child_gone = 0, pid = 0;
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static volatile sig_atomic_t terminate = 0, child_gone = 0, pid = 0,
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do_log_reopen = 0;
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int
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main(int argc, char *argv[])
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@ -84,7 +89,7 @@ main(int argc, char *argv[])
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sigset_t mask_susp, mask_orig, mask_read, mask_term;
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struct log_params logpar;
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int pfd[2] = { -1, -1 }, outfd = -1;
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int stdmask, logpri, logfac;
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int stdmask, logpri, logfac, log_reopen;
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struct pidfh *ppfh, *pfh;
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char *p;
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@ -97,9 +102,10 @@ main(int argc, char *argv[])
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logtag = "daemon";
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restart = 0;
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dosyslog = 0;
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log_reopen = 0;
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outfn = NULL;
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title = NULL;
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while ((ch = getopt(argc, argv, "cfSp:P:ru:o:s:l:t:l:m:R:T:")) != -1) {
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while ((ch = getopt(argc, argv, "cfHSp:P:ru:o:s:l:t:l:m:R:T:")) != -1) {
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switch (ch) {
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case 'c':
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nochdir = 0;
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@ -107,6 +113,9 @@ main(int argc, char *argv[])
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case 'f':
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noclose = 0;
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break;
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case 'H':
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log_reopen = 1;
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break;
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case 'l':
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logfac = get_log_mapping(optarg, facilitynames);
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if (logfac == -1)
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@ -168,7 +177,7 @@ main(int argc, char *argv[])
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title = argv[0];
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if (outfn) {
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outfd = open(outfn, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0600);
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outfd = open_log(outfn);
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if (outfd == -1)
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err(7, "open");
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}
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@ -201,7 +210,7 @@ main(int argc, char *argv[])
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*/
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pid = -1;
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if (pidfile || ppidfile || restart || outfd != -1 || dosyslog) {
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struct sigaction act_term, act_chld;
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struct sigaction act_term, act_chld, act_hup;
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/* Avoid PID racing with SIGCHLD and SIGTERM. */
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memset(&act_term, 0, sizeof(act_term));
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@ -214,6 +223,10 @@ main(int argc, char *argv[])
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sigemptyset(&act_chld.sa_mask);
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sigaddset(&act_chld.sa_mask, SIGTERM);
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memset(&act_hup, 0, sizeof(act_hup));
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act_hup.sa_handler = handle_hup;
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sigemptyset(&act_hup.sa_mask);
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/* Block these when avoiding racing before sigsuspend(). */
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sigemptyset(&mask_susp);
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sigaddset(&mask_susp, SIGTERM);
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@ -251,6 +264,12 @@ main(int argc, char *argv[])
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logpar.dosyslog = dosyslog;
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logpar.logpri = logpri;
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logpar.noclose = noclose;
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logpar.outfn = outfn;
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if (log_reopen && outfd >= 0 &&
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sigaction(SIGHUP, &act_hup, NULL) == -1) {
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warn("sigaction");
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goto exit;
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}
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restart:
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if (pipe(pfd))
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err(1, "pipe");
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@ -465,6 +484,8 @@ listen_child(int fd, struct log_params *logpar)
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assert(logpar);
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assert(bytes_read < LBUF_SIZE - 1);
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if (do_log_reopen)
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reopen_log(logpar);
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rv = read(fd, buf + bytes_read, LBUF_SIZE - bytes_read - 1);
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if (rv > 0) {
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unsigned char *cp;
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@ -543,9 +564,9 @@ handle_term(int signo)
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}
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static void
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handle_chld(int signo)
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handle_chld(int signo __unused)
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{
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(void)signo;
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for (;;) {
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int rv = waitpid(-1, NULL, WNOHANG);
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if (pid == rv) {
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@ -558,11 +579,37 @@ handle_chld(int signo)
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}
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}
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static void
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handle_hup(int signo __unused)
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{
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do_log_reopen = 1;
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}
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static int
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open_log(const char *outfn)
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{
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return open(outfn, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0600);
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}
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static void
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reopen_log(struct log_params *lpp)
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{
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int outfd;
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do_log_reopen = 0;
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outfd = open_log(lpp->outfn);
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if (lpp->outfd >= 0)
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close(lpp->outfd);
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lpp->outfd = outfd;
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}
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static void
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usage(void)
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{
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(void)fprintf(stderr,
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"usage: daemon [-cfrS] [-p child_pidfile] [-P supervisor_pidfile]\n"
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"usage: daemon [-cfHrS] [-p child_pidfile] [-P supervisor_pidfile]\n"
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" [-u user] [-o output_file] [-t title]\n"
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" [-l syslog_facility] [-s syslog_priority]\n"
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" [-T syslog_tag] [-m output_mask] [-R restart_delay_secs]\n"
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