The branch main has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=8536447a07fa29073f93af70808db58c760aa6f9
commit 8536447a07fa29073f93af70808db58c760aa6f9
Author: Jake Freeland <jf...@freebsd.org>
AuthorDate: 2023-09-01 02:51:28 +0000
Commit: Mark Johnston <ma...@freebsd.org>
CommitDate: 2023-09-28 15:51:54 +0000
syslogd: Use pipe to communicate with daemon
Previously, syslogd's daemon process would signal that it had finished
initialization using SIGALRM. In capability mode, signal delivery is not
allowed, so use a pipe to indicate that it is ready to accept messages.
Reviewed by: markj
MFC after: 3 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D41459
---
usr.sbin/syslogd/syslogd.c | 100 ++++++++++++++++++++-------------------------
1 file changed, 44 insertions(+), 56 deletions(-)
diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index 3f9633ca8c35..8d2f3c3edf14 100644
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -135,6 +135,7 @@ static char sccsid[] = "@(#)syslogd.c 8.3 (Berkeley)
4/4/94";
#include <limits.h>
#include <netdb.h>
#include <paths.h>
+#include <poll.h>
#include <regex.h>
#include <signal.h>
#include <stdbool.h>
@@ -471,7 +472,6 @@ static bool validate(struct sockaddr *, const char *);
static void unmapped(struct sockaddr *);
static void wallmsg(struct filed *, struct iovec *, const int iovlen);
static int waitdaemon(int);
-static void timedout(int);
static void increase_rcvbuf(int);
static void
@@ -599,8 +599,8 @@ main(int argc, char *argv[])
struct sigaction act = { };
struct kevent ev;
struct socklist *sl;
- pid_t ppid = -1, spid;
- int ch, kq, s;
+ pid_t spid;
+ int ch, kq, ppipe_w = -1, s;
char *p;
bool bflag = false, pflag = false, Sflag = false;
@@ -813,14 +813,9 @@ main(int argc, char *argv[])
(void)strlcpy(bootfile, getbootfile(), sizeof(bootfile));
- if ((!Foreground) && (!Debug)) {
- ppid = waitdaemon(30);
- if (ppid < 0) {
- warn("could not become daemon");
- pidfile_remove(pfh);
- exit(1);
- }
- } else if (Debug)
+ if (!Foreground && !Debug)
+ ppipe_w = waitdaemon(30);
+ else if (Debug)
setlinebuf(stdout);
kq = kqueue();
@@ -868,9 +863,14 @@ main(int argc, char *argv[])
for (;;) {
if (needdofsync) {
dofsync();
- if (ppid != -1) {
- kill(ppid, SIGALRM);
- ppid = -1;
+ if (ppipe_w != -1) {
+ /*
+ * Close our end of the pipe so our
+ * parent knows that we have finished
+ * initialization.
+ */
+ (void)close(ppipe_w);
+ ppipe_w = -1;
}
}
if (kevent(kq, NULL, 0, &ev, 1, NULL) == -1) {
@@ -3237,64 +3237,52 @@ markit(void)
/*
* fork off and become a daemon, but wait for the child to come online
* before returning to the parent, or we get disk thrashing at boot etc.
- * Set a timer so we don't hang forever if it wedges.
*/
static int
waitdaemon(int maxwait)
{
- int status;
- pid_t pid, childpid;
+ struct pollfd pollfd;
+ int events, pipefd[2], status;
+ pid_t pid;
- switch (childpid = fork()) {
- case -1:
- return (-1);
- case 0:
- break;
- default:
- signal(SIGALRM, timedout);
- alarm(maxwait);
- while ((pid = wait3(&status, 0, NULL)) != -1) {
+ if (pipe(pipefd) == -1) {
+ warn("failed to daemonize, pipe");
+ die(0);
+ }
+ pid = fork();
+ if (pid == -1) {
+ warn("failed to daemonize, fork");
+ die(0);
+ } else if (pid > 0) {
+ close(pipefd[1]);
+ pollfd.fd = pipefd[0];
+ pollfd.events = POLLHUP;
+ events = poll(&pollfd, 1, maxwait * 1000);
+ if (events == -1)
+ err(1, "failed to daemonize, poll");
+ else if (events == 0)
+ errx(1, "timed out waiting for child");
+ if (waitpid(pid, &status, WNOHANG) > 0) {
if (WIFEXITED(status))
errx(1, "child pid %d exited with return code
%d",
- pid, WEXITSTATUS(status));
+ pid, WEXITSTATUS(status));
if (WIFSIGNALED(status))
errx(1, "child pid %d exited on signal %d%s",
- pid, WTERMSIG(status),
- WCOREDUMP(status) ? " (core dumped)" :
- "");
- if (pid == childpid) /* it's gone... */
- break;
+ pid, WTERMSIG(status),
+ WCOREDUMP(status) ? " (core dumped)" : "");
}
exit(0);
}
-
- if (setsid() == -1)
- return (-1);
-
+ close(pipefd[0]);
+ if (setsid() == -1) {
+ warn("failed to daemonize, setsid");
+ die(0);
+ }
(void)chdir("/");
(void)dup2(nulldesc, STDIN_FILENO);
(void)dup2(nulldesc, STDOUT_FILENO);
(void)dup2(nulldesc, STDERR_FILENO);
- return (getppid());
-}
-
-/*
- * We get a SIGALRM from the child when it's running and finished doing it's
- * fsync()'s or O_SYNC writes for all the boot messages.
- *
- * We also get a signal from the kernel if the timer expires, so check to
- * see what happened.
- */
-static void
-timedout(int sig __unused)
-{
- int left;
- left = alarm(0);
- signal(SIGALRM, SIG_DFL);
- if (left == 0)
- errx(1, "timed out waiting for child");
- else
- _exit(0);
+ return (pipefd[1]);
}
/*
