cron: add log suppression and mail suppression for successful runs
This commit adds two new extensions to crontab, ported from OpenBSD: - -n: suppress mail on succesful run - -q: suppress logging of command execution The -q option appears decades old, but -n is relatively new. The original proposal by Job Snijder can be found here [1], and gives very convincing reasons for inclusion in base. This patch is a nearly identical port of OpenBSD cron for -q and -n features. It is written to follow existing conventions and style of the existing codebase. Example usage: # should only send email, but won't show up in log * * * * * -q date # should not send email * * * * * -n date # should not send email or log * * * * * -n -q date # should send email because of ping failure * * * * * -n -q ping -c 1 5.5.5.5 [1]: https://marc.info/?l=openbsd-tech&m=152874866117948&w=2 PR: 237538 Submitted by: Naveen Nathan <freebsd_t.lastninja.net> Reviewed by: bcr (manpages) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D20046
This commit is contained in:
Kyle Evans
parent
e44ed9d3d4
commit
5b80de237b
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=352668
@ -191,6 +191,8 @@ typedef struct _entry {
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#define NOT_UNTIL 0x10
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#define SEC_RES 0x20
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#define INTERVAL 0x40
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#define DONT_LOG 0x80
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#define MAIL_WHEN_ERR 0x100
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time_t lastrun;
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} entry;
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@ -257,7 +259,7 @@ user *load_user(int, struct passwd *, char *),
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entry *load_entry(FILE *, void (*)(char *),
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struct passwd *, char **);
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FILE *cron_popen(char *, char *, entry *);
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FILE *cron_popen(char *, char *, entry *, PID_T *);
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/* in the C tradition, we only create
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@ -41,6 +41,7 @@ static const char rcsid[] =
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static void child_process(entry *, user *),
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do_univ(user *);
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static WAIT_T wait_on_child(PID_T, const char *);
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void
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do_command(e, u)
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@ -94,7 +95,10 @@ child_process(e, u)
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int stdin_pipe[2], stdout_pipe[2];
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register char *input_data;
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char *usernm, *mailto, *mailfrom;
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int children = 0;
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PID_T jobpid, stdinjob, mailpid;
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register FILE *mail;
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register int bytes = 1;
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int status = 0;
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# if defined(LOGIN_CAP)
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struct passwd *pwd;
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login_cap_t *lc;
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@ -216,7 +220,7 @@ child_process(e, u)
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/* fork again, this time so we can exec the user's command.
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*/
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switch (vfork()) {
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switch (jobpid = vfork()) {
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case -1:
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log_it("CRON",getpid(),"error","can't vfork");
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exit(ERROR_EXIT);
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@ -237,7 +241,7 @@ child_process(e, u)
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* the actual user command shell was going to get and the
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* PID is part of the log message.
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*/
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/*local*/{
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if ((e->flags & DONT_LOG) == 0) {
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char *x = mkprints((u_char *)e->cmd, strlen(e->cmd));
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log_it(usernm, getpid(), "CMD", x);
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@ -359,8 +363,6 @@ child_process(e, u)
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break;
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}
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children++;
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/* middle process, child of original cron, parent of process running
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* the user's command.
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*/
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@ -384,7 +386,7 @@ child_process(e, u)
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* we would block here. thus we must fork again.
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*/
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if (*input_data && fork() == 0) {
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if (*input_data && (stdinjob = fork()) == 0) {
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register FILE *out = fdopen(stdin_pipe[WRITE_PIPE], "w");
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register int need_newline = FALSE;
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register int escaped = FALSE;
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@ -440,8 +442,6 @@ child_process(e, u)
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*/
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close(stdin_pipe[WRITE_PIPE]);
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children++;
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/*
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* read output from the grandchild. it's stderr has been redirected to
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* it's stdout, which has been redirected to our pipe. if there is any
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@ -462,10 +462,6 @@ child_process(e, u)
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ch = getc(in);
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if (ch != EOF) {
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register FILE *mail;
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register int bytes = 1;
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int status = 0;
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Debug(DPROC|DEXT,
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("[%d] got data (%x:%c) from grandchild\n",
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getpid(), ch, ch))
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@ -500,7 +496,7 @@ child_process(e, u)
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hostname[sizeof(hostname) - 1] = '\0';
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(void) snprintf(mailcmd, sizeof(mailcmd),
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MAILARGS, MAILCMD);
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if (!(mail = cron_popen(mailcmd, "w", e))) {
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if (!(mail = cron_popen(mailcmd, "w", e, &mailpid))) {
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warn("%s", MAILCMD);
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(void) _exit(ERROR_EXIT);
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}
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@ -538,28 +534,56 @@ child_process(e, u)
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if (mailto)
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putc(ch, mail);
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}
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}
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/*if data from grandchild*/
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/* only close pipe if we opened it -- i.e., we're
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* mailing...
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Debug(DPROC, ("[%d] got EOF from grandchild\n", getpid()))
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/* also closes stdout_pipe[READ_PIPE] */
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fclose(in);
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}
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/* wait for children to die.
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*/
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if (jobpid > 0) {
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WAIT_T waiter;
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waiter = wait_on_child(jobpid, "grandchild command job");
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/* If everything went well, and -n was set, _and_ we have mail,
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* we won't be mailing... so shoot the messenger!
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*/
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if (WIFEXITED(waiter) && WEXITSTATUS(waiter) == 0
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&& (e->flags & MAIL_WHEN_ERR) == MAIL_WHEN_ERR
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&& mailto) {
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Debug(DPROC, ("[%d] %s executed successfully, mail suppressed\n",
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getpid(), "grandchild command job"))
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kill(mailpid, SIGKILL);
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(void)fclose(mail);
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mailto = NULL;
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}
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/* only close pipe if we opened it -- i.e., we're
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* mailing...
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*/
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if (mailto) {
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Debug(DPROC, ("[%d] closing pipe to mail\n",
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getpid()))
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/* Note: the pclose will probably see
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* the termination of the grandchild
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* in addition to the mail process, since
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* it (the grandchild) is likely to exit
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* after closing its stdout.
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*/
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if (mailto) {
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Debug(DPROC, ("[%d] closing pipe to mail\n",
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getpid()))
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/* Note: the pclose will probably see
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* the termination of the grandchild
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* in addition to the mail process, since
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* it (the grandchild) is likely to exit
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* after closing its stdout.
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*/
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status = cron_pclose(mail);
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}
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status = cron_pclose(mail);
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/* if there was output and we could not mail it,
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* log the facts so the poor user can figure out
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* what's going on.
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*/
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if (mailto && status) {
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if (status) {
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char buf[MAX_TEMPSTR];
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snprintf(buf, sizeof(buf),
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@ -568,35 +592,38 @@ child_process(e, u)
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status);
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log_it(usernm, getpid(), "MAIL", buf);
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}
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} /*if data from grandchild*/
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Debug(DPROC, ("[%d] got EOF from grandchild\n", getpid()))
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fclose(in); /* also closes stdout_pipe[READ_PIPE] */
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}
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/* wait for children to die.
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*/
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for (; children > 0; children--)
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{
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WAIT_T waiter;
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PID_T pid;
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Debug(DPROC, ("[%d] waiting for grandchild #%d to finish\n",
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getpid(), children))
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pid = wait(&waiter);
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if (pid < OK) {
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Debug(DPROC, ("[%d] no more grandchildren--mail written?\n",
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getpid()))
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break;
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}
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Debug(DPROC, ("[%d] grandchild #%d finished, status=%04x",
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getpid(), pid, WEXITSTATUS(waiter)))
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if (WIFSIGNALED(waiter) && WCOREDUMP(waiter))
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Debug(DPROC, (", dumped core"))
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Debug(DPROC, ("\n"))
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}
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if (*input_data && stdinjob > 0)
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wait_on_child(stdinjob, "grandchild stdinjob");
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}
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static WAIT_T
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wait_on_child(PID_T childpid, const char *name) {
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WAIT_T waiter;
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PID_T pid;
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Debug(DPROC, ("[%d] waiting for %s (%d) to finish\n",
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getpid(), name, childpid))
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#ifdef POSIX
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while ((pid = waitpid(childpid, &waiter, 0)) < 0 && errno == EINTR)
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#else
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while ((pid = wait4(childpid, &waiter, 0, NULL)) < 0 && errno == EINTR)
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#endif
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;
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if (pid < OK)
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return waiter;
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Debug(DPROC, ("[%d] %s (%d) finished, status=%04x",
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getpid(), name, pid, WEXITSTATUS(waiter)))
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if (WIFSIGNALED(waiter) && WCOREDUMP(waiter))
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Debug(DPROC, (", dumped core"))
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Debug(DPROC, ("\n"))
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return waiter;
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}
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@ -55,9 +55,10 @@ static PID_T *pids;
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static int fds;
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FILE *
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cron_popen(program, type, e)
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cron_popen(program, type, e, pidptr)
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char *program, *type;
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entry *e;
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PID_T *pidptr;
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{
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register char *cp;
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FILE *iop;
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@ -218,6 +219,9 @@ cron_popen(program, type, e)
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free((char *)argv[argc]);
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}
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#endif
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*pidptr = pid;
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return(iop);
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}
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@ -17,7 +17,7 @@
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 19, 2019
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.Dd September 24, 2019
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.Dt CRONTAB 5
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.Os
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.Sh NAME
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@ -199,6 +199,8 @@ lists of names are not allowed.
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.Pp
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The ``sixth'' field (the rest of the line) specifies the command to be
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run.
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One or more command options may precede the command to modify processing
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behavior.
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The entire command portion of the line, up to a newline or %
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character, will be executed by
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.Pa /bin/sh
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@ -211,6 +213,22 @@ Percent-signs (%) in the command, unless escaped with backslash
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after the first % will be sent to the command as standard
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input.
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.Pp
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The following command options can be supplied:
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.Bl -tag -width Ds
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.It Fl n
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No mail is sent after a successful run.
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The execution output will only be mailed if the command exits with a non-zero
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exit code.
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The
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.Fl n
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option is an attempt to cure potentially copious volumes of mail coming from
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.Xr cron 8 .
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.It Fl q
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Execution will not be logged.
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.El
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.sp
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Duplicate options are not allowed.
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.Pp
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Note: The day of a command's execution can be specified by two
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fields \(em day of month, and day of week.
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If both fields are
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@ -271,6 +289,10 @@ MAILTO=paul
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5 4 * * sun echo "run at 5 after 4 every sunday"
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# run at 5 minutes intervals, no matter how long it takes
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@300 svnlite up /usr/src
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# run every minute, suppress logging
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* * * * * -q date
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# run every minute, only send mail if ping fails
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* * * * * -n ping -c 1 freebsd.org
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.Ed
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.Sh SEE ALSO
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.Xr crontab 1 ,
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@ -314,6 +336,14 @@ All of the
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.Sq @
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directives that can appear in place of the first five fields
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are extensions.
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.Pp
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Command processing can be modified using command options.
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The
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.Sq -q
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option suppresses logging.
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The
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.Sq -n
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option does not mail on successful run.
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.Sh AUTHORS
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.An Paul Vixie Aq Mt paul@vix.com
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.Sh BUGS
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@ -35,7 +35,8 @@ static const char rcsid[] =
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typedef enum ecode {
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e_none, e_minute, e_hour, e_dom, e_month, e_dow,
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e_cmd, e_timespec, e_username, e_group, e_mem
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e_cmd, e_timespec, e_username, e_group, e_option,
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e_mem
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#ifdef LOGIN_CAP
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, e_class
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#endif
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@ -58,6 +59,7 @@ static char *ecodes[] =
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"bad time specifier",
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"bad username",
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"bad group name",
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"bad option",
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"out of memory",
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#ifdef LOGIN_CAP
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"bad class name",
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@ -429,6 +431,53 @@ load_entry(file, error_func, pw, envp)
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}
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#endif
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Debug(DPARS, ("load_entry()...checking for command options\n"))
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ch = get_char(file);
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while (ch == '-') {
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Debug(DPARS|DEXT, ("load_entry()...expecting option\n"))
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switch (ch = get_char(file)) {
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case 'n':
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Debug(DPARS|DEXT, ("load_entry()...got MAIL_WHEN_ERR ('n') option\n"))
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/* only allow the user to set the option once */
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if ((e->flags & MAIL_WHEN_ERR) == MAIL_WHEN_ERR) {
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Debug(DPARS|DEXT, ("load_entry()...duplicate MAIL_WHEN_ERR ('n') option\n"))
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ecode = e_option;
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goto eof;
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}
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e->flags |= MAIL_WHEN_ERR;
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break;
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case 'q':
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Debug(DPARS|DEXT, ("load_entry()...got DONT_LOG ('q') option\n"))
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/* only allow the user to set the option once */
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if ((e->flags & DONT_LOG) == DONT_LOG) {
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Debug(DPARS|DEXT, ("load_entry()...duplicate DONT_LOG ('q') option\n"))
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ecode = e_option;
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goto eof;
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}
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e->flags |= DONT_LOG;
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break;
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default:
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Debug(DPARS|DEXT, ("load_entry()...invalid option '%c'\n", ch))
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ecode = e_option;
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goto eof;
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}
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ch = get_char(file);
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if (ch!='\t' && ch!=' ') {
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ecode = e_option;
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goto eof;
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}
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Skip_Blanks(ch, file)
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if (ch == EOF || ch == '\n') {
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ecode = e_cmd;
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goto eof;
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}
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}
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unget_char(ch, file);
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Debug(DPARS, ("load_entry()...about to parse command\n"))
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/* Everything up to the next \n or EOF is part of the command...
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