[Bug 237538] [patch] cron: add log suppression and mail suppression for successful runs
bugzilla-noreply at freebsd.org
bugzilla-noreply at freebsd.org
Wed Apr 24 19:37:53 UTC 2019
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=237538
--- Comment #3 from Naveen Nathan <freebsd at t.lastninja.net> ---
Comment on attachment 203978
--> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=203978
Add crontab support for -q (log suppression) and -n (mail suppression for
successful run).
diff --git a/usr.sbin/cron/cron/cron.h b/usr.sbin/cron/cron/cron.h
index bb4f5287daea..f0f9e88d6b59 100644
--- a/usr.sbin/cron/cron/cron.h
+++ b/usr.sbin/cron/cron/cron.h
@@ -191,6 +191,8 @@ typedef struct _entry {
#define NOT_UNTIL 0x10
#define SEC_RES 0x20
#define INTERVAL 0x40
+#define DONT_LOG 0x80
+#define MAIL_WHEN_ERR 0x100
time_t lastrun;
} entry;
@@ -257,7 +259,7 @@ user *load_user(int, struct passwd *, char
*),
entry *load_entry(FILE *, void (*)(char *),
struct passwd *, char **);
-FILE *cron_popen(char *, char *, entry *);
+FILE *cron_popen(char *, char *, entry *, PID_T *);
/* in the C tradition, we only create
diff --git a/usr.sbin/cron/cron/do_command.c b/usr.sbin/cron/cron/do_command.c
index 13d14e442a27..b54297c02cb2 100644
--- a/usr.sbin/cron/cron/do_command.c
+++ b/usr.sbin/cron/cron/do_command.c
@@ -41,6 +41,7 @@ static const char rcsid[] =
static void child_process(entry *, user *),
do_univ(user *);
+static WAIT_T wait_on_child(PID_T, char *);
void
do_command(e, u)
@@ -94,7 +95,12 @@ child_process(e, u)
int stdin_pipe[2], stdout_pipe[2];
register char *input_data;
char *usernm, *mailto, *mailfrom;
- int children = 0;
+ PID_T jobpid, stdinjob, mailpid;
+
+ register FILE *mail;
+ register int bytes = 1;
+ int status = 0;
+
# if defined(LOGIN_CAP)
struct passwd *pwd;
login_cap_t *lc;
@@ -216,7 +222,8 @@ child_process(e, u)
/* fork again, this time so we can exec the user's command.
*/
- switch (vfork()) {
+
+ switch (jobpid = vfork()) {
case -1:
log_it("CRON",getpid(),"error","can't vfork");
exit(ERROR_EXIT);
@@ -237,7 +244,7 @@ child_process(e, u)
* the actual user command shell was going to get and the
* PID is part of the log message.
*/
- /*local*/{
+ if ((e->flags & DONT_LOG) == 0) {
char *x = mkprints((u_char *)e->cmd, strlen(e->cmd));
log_it(usernm, getpid(), "CMD", x);
@@ -359,8 +366,6 @@ child_process(e, u)
break;
}
- children++;
-
/* middle process, child of original cron, parent of process running
* the user's command.
*/
@@ -384,7 +389,9 @@ child_process(e, u)
* we would block here. thus we must fork again.
*/
- if (*input_data && fork() == 0) {
+ stdinjob = 0;
+
+ if (*input_data && (stdinjob = fork()) == 0) {
register FILE *out = fdopen(stdin_pipe[WRITE_PIPE], "w");
register int need_newline = FALSE;
register int escaped = FALSE;
@@ -440,8 +447,6 @@ child_process(e, u)
*/
close(stdin_pipe[WRITE_PIPE]);
- children++;
-
/*
* read output from the grandchild. it's stderr has been redirected to
* it's stdout, which has been redirected to our pipe. if there is any
@@ -462,10 +467,6 @@ child_process(e, u)
ch = getc(in);
if (ch != EOF) {
- register FILE *mail;
- register int bytes = 1;
- int status = 0;
-
Debug(DPROC|DEXT,
("[%d] got data (%x:%c) from grandchild\n",
getpid(), ch, ch))
@@ -500,7 +501,7 @@ child_process(e, u)
hostname[sizeof(hostname) - 1] = '\0';
(void) snprintf(mailcmd, sizeof(mailcmd),
MAILARGS, MAILCMD);
- if (!(mail = cron_popen(mailcmd, "w", e))) {
+ if (!(mail = cron_popen(mailcmd, "w", e,
&mailpid))) {
warn("%s", MAILCMD);
(void) _exit(ERROR_EXIT);
}
@@ -538,28 +539,54 @@ child_process(e, u)
if (mailto)
putc(ch, mail);
}
+ } /*if data from grandchild*/
- /* only close pipe if we opened it -- i.e., we're
- * mailing...
- */
+ Debug(DPROC, ("[%d] got EOF from grandchild\n", getpid()))
+
+ fclose(in); /* also closes stdout_pipe[READ_PIPE] */
+ }
+
+ /* wait for children to die.
+ */
+ if (jobpid > 0) {
+ WAIT_T waiter;
+
+ waiter = wait_on_child(jobpid, "grandchild command job");
+
+ /* If everything went well, and -n was set, _and_ we have mail,
+ * we won't be mailing... so shoot the messenger!
+ */
+ if (WIFEXITED(waiter) && WEXITSTATUS(waiter) == 0
+ && (e->flags & MAIL_WHEN_ERR) == MAIL_WHEN_ERR
+ && mailto) {
+ Debug(DPROC, ("[%d] %s executed successful, mail
suppressed\n",
+ getpid(), "grandchild command job"))
+ kill(mailpid, SIGKILL);
+ (void)fclose(mail);
+ mailto = NULL;
+ }
- if (mailto) {
- Debug(DPROC, ("[%d] closing pipe to mail\n",
- getpid()))
- /* Note: the pclose will probably see
- * the termination of the grandchild
- * in addition to the mail process, since
- * it (the grandchild) is likely to exit
- * after closing its stdout.
- */
- status = cron_pclose(mail);
- }
+
+ /* only close pipe if we opened it -- i.e., we're
+ * mailing...
+ */
+
+ if (mailto) {
+ Debug(DPROC, ("[%d] closing pipe to mail\n",
+ getpid()))
+ /* Note: the pclose will probably see
+ * the termination of the grandchild
+ * in addition to the mail process, since
+ * it (the grandchild) is likely to exit
+ * after closing its stdout.
+ */
+ status = cron_pclose(mail);
/* if there was output and we could not mail it,
* log the facts so the poor user can figure out
* what's going on.
*/
- if (mailto && status) {
+ if (status) {
char buf[MAX_TEMPSTR];
snprintf(buf, sizeof(buf),
@@ -568,35 +595,38 @@ child_process(e, u)
status);
log_it(usernm, getpid(), "MAIL", buf);
}
+ }
+ }
- } /*if data from grandchild*/
+ if (stdinjob > 0)
+ wait_on_child(stdinjob, "grandchild stdinjob");
+}
- Debug(DPROC, ("[%d] got EOF from grandchild\n", getpid()))
+static WAIT_T
+wait_on_child(PID_T childpid, char *name) {
+ WAIT_T waiter;
+ PID_T pid;
- fclose(in); /* also closes stdout_pipe[READ_PIPE] */
- }
+ Debug(DPROC, ("[%d] waiting for %s (%d) to finish\n",
+ getpid(), name, childpid))
- /* wait for children to die.
- */
- for (; children > 0; children--)
- {
- WAIT_T waiter;
- PID_T pid;
-
- Debug(DPROC, ("[%d] waiting for grandchild #%d to finish\n",
- getpid(), children))
- pid = wait(&waiter);
- if (pid < OK) {
- Debug(DPROC, ("[%d] no more grandchildren--mail
written?\n",
- getpid()))
- break;
- }
- Debug(DPROC, ("[%d] grandchild #%d finished, status=%04x",
- getpid(), pid, WEXITSTATUS(waiter)))
- if (WIFSIGNALED(waiter) && WCOREDUMP(waiter))
- Debug(DPROC, (", dumped core"))
- Debug(DPROC, ("\n"))
- }
+#ifdef POSIX
+ while ((pid = waitpid(childpid, &waiter, 0)) < 0 && errno == EINTR)
+#else
+ while ((pid = wait4(childpid, &waiter, 0, NULL)) < 0 && errno == EINTR)
+#endif
+ ;
+
+ if (pid < OK)
+ return waiter;
+
+ Debug(DPROC, ("[%d] %s (%d) finished, status=%04x",
+ getpid(), name, pid, WEXITSTATUS(waiter)))
+ if (WIFSIGNALED(waiter) && WCOREDUMP(waiter))
+ Debug(DPROC, (", dumped core"))
+ Debug(DPROC, ("\n"))
+
+ return waiter;
}
diff --git a/usr.sbin/cron/cron/popen.c b/usr.sbin/cron/cron/popen.c
index 01e62bf2bab2..73e6e28d748a 100644
--- a/usr.sbin/cron/cron/popen.c
+++ b/usr.sbin/cron/cron/popen.c
@@ -55,9 +55,10 @@ static PID_T *pids;
static int fds;
FILE *
-cron_popen(program, type, e)
+cron_popen(program, type, e, pidptr)
char *program, *type;
entry *e;
+ PID_T *pidptr;
{
register char *cp;
FILE *iop;
@@ -218,6 +219,9 @@ cron_popen(program, type, e)
free((char *)argv[argc]);
}
#endif
+
+ *pidptr = pid;
+
return(iop);
}
diff --git a/usr.sbin/cron/crontab/crontab.5 b/usr.sbin/cron/crontab/crontab.5
index 8988574f3745..354aba3dd8fb 100644
--- a/usr.sbin/cron/crontab/crontab.5
+++ b/usr.sbin/cron/crontab/crontab.5
@@ -198,7 +198,8 @@ Ranges or
lists of names are not allowed.
.Pp
The ``sixth'' field (the rest of the line) specifies the command to be
-run.
+run. One or more command options may precede the command to modify
+processing behavior.
The entire command portion of the line, up to a newline or %
character, will be executed by
.Pa /bin/sh
@@ -211,6 +212,22 @@ Percent-signs (%) in the command, unless escaped with
backslash
after the first % will be sent to the command as standard
input.
.Pp
+The following command options can be supplied:
+.Bl -tag -width Ds
+.It Fl n
+No mail is sent after a successful run.
+The execution output will only be mailed if the command exits with a non-zero
+exit code.
+The
+.Fl n
+option is an attempt to cure potentially copious volumes of mail coming from
+.Xr cron 8 .
+.It Fl q
+Execution will not be logged.
+.El
+
+Duplicate options are not allowed.
+.Pp
Note: The day of a command's execution can be specified by two
fields \(em day of month, and day of week.
If both fields are
@@ -261,6 +278,10 @@ SHELL=/bin/sh
# mail any output to `paul', no matter whose crontab this is
MAILTO=paul
#
+# run every minute, suppress logging
+* * * * * -q date
+# run every minute, suppress logging and mail
+* * * * * -q -n echo "no-op"
# run five minutes after midnight, every day
5 0 * * * $HOME/bin/daily.job >> $HOME/tmp/out 2>&1
# run at 2:15pm on the first of every month -- output mailed to paul
@@ -314,6 +335,12 @@ All of the
.Sq @
directives that can appear in place of the first five fields
are extensions.
+.Pp
+Command processing can be modified using command options. The
+.Sq -q
+option suppresses logging. The
+.Sq -n
+option does not mail on successful run.
.Sh AUTHORS
.An Paul Vixie Aq Mt paul at vix.com
.Sh BUGS
diff --git a/usr.sbin/cron/lib/entry.c b/usr.sbin/cron/lib/entry.c
index a8ec3ae8b568..a81a4ee78c30 100644
--- a/usr.sbin/cron/lib/entry.c
+++ b/usr.sbin/cron/lib/entry.c
@@ -35,7 +35,8 @@ static const char rcsid[] =
typedef enum ecode {
e_none, e_minute, e_hour, e_dom, e_month, e_dow,
- e_cmd, e_timespec, e_username, e_group, e_mem
+ e_cmd, e_timespec, e_username, e_group, e_option,
+ e_mem
#ifdef LOGIN_CAP
, e_class
#endif
@@ -58,6 +59,7 @@ static char *ecodes[] =
"bad time specifier",
"bad username",
"bad group name",
+ "bad option",
"out of memory",
#ifdef LOGIN_CAP
"bad class name",
@@ -429,6 +431,53 @@ load_entry(file, error_func, pw, envp)
}
#endif
+ Debug(DPARS, ("load_entry()...checking for command options\n"))
+
+ ch = get_char(file);
+
+ while (ch == '-') {
+ Debug(DPARS|DEXT, ("load_entry()...expecting option\n"))
+ switch(ch = get_char(file)) {
+ case 'n':
+ Debug(DPARS|DEXT, ("load_entry()...got MAIL_WHEN_ERR
('n') option\n"))
+ /* only allow the user to set the option once */
+ if ((e->flags & MAIL_WHEN_ERR) == MAIL_WHEN_ERR) {
+ Debug(DPARS|DEXT, ("load_entry()...duplicate
MAIL_WHEN_ERR ('n') option\n"))
+ ecode = e_option;
+ goto eof;
+ }
+ e->flags |= MAIL_WHEN_ERR;
+ break;
+ case 'q':
+ Debug(DPARS|DEXT, ("load_entry()...got DONT_LOG ('q')
option\n"))
+ /* only allow the user to set the option once */
+ if ((e->flags & DONT_LOG) == DONT_LOG) {
+ Debug(DPARS|DEXT, ("load_entry()...duplicate
DONT_LOG ('q') option\n"))
+ ecode = e_option;
+ goto eof;
+ }
+ e->flags |= DONT_LOG;
+ break;
+ default:
+ Debug(DPARS|DEXT, ("load_entry()...invalid option
'%c'\n", ch))
+ ecode = e_option;
+ goto eof;
+ }
+ ch = get_char(file);
+ if (ch!='\t' && ch!=' ') {
+ ecode = e_option;
+ goto eof;
+ }
+
+ Skip_Blanks(ch, file)
+ if (ch == EOF || ch == '\n') {
+ ecode = e_cmd;
+ goto eof;
+ }
+ }
+
+ unget_char(ch, file);
+
Debug(DPARS, ("load_entry()...about to parse command\n"))
/* Everything up to the next \n or EOF is part of the command...
--
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