Attachment 215283 Details for Bug 246597 – fix the race between SIGHUP and exports reload

[patch] fix the race between SIGHUP and exports reload

mountd-reload.patch (text/plain), 2.42 KB, created by Rick Macklem on 2020-06-06 00:46:12 UTC

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Creator: Rick Macklem

Created: 2020-06-06 00:46:12 UTC

Size: 2.42 KB

patch

obsolete

>--- usr.sbin/mountd/mountd.c.reload	2020-06-03 18:30:40.157353000 -0700
>+++ usr.sbin/mountd/mountd.c	2020-06-04 15:34:57.131468000 -0700
>@@ -193,6 +193,12 @@ struct fhreturn {
> 
> #define	GETPORT_MAXTRY	20	/* Max tries to get a port # */
> 
>+/*
>+ * How long to delay a reload of exports when there are RPC request(s)
>+ * to process, in usec.  Must be less than 1second.
>+ */
>+#define	RELOADDELAY	250000
>+
> /* Global defs */
> static char	*add_expdir(struct dirlist **, char *, int);
> static void	add_dlist(struct dirlist **, struct dirlist *,
>@@ -413,6 +419,10 @@ main(int argc, char **argv)
> 	int maxrec = RPC_MAXDATASIZE;
> 	int attempt_cnt, port_len, port_pos, ret;
> 	char **port_list;
>+	uint64_t curtime, nexttime;
>+	struct timeval tv;
>+	struct timespec tp;
>+	sigset_t sighup_mask;
> 
> 	/* Check that another mountd isn't already running. */
> 	pfh = pidfile_open(_PATH_MOUNTDPID, 0600, &otherpid);
>@@ -668,19 +678,49 @@ main(int argc, char **argv)
> 	}
> 
> 	/* Expand svc_run() here so that we can call get_exportlist(). */
>+	curtime = nexttime = 0;
>+	sigemptyset(&sighup_mask);
>+	sigaddset(&sighup_mask, SIGHUP);
> 	for (;;) {
>-		if (got_sighup) {
>-			get_exportlist(1);
>+		clock_gettime(CLOCK_MONOTONIC, &tp);
>+		curtime = tp.tv_sec;
>+		curtime = curtime * 1000000 + tp.tv_nsec / 1000;
>+		sigprocmask(SIG_BLOCK, &sighup_mask, NULL);
>+		if (got_sighup && curtime >= nexttime) {
> 			got_sighup = 0;
>-		}
>+			sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL);
>+			get_exportlist(1);
>+			clock_gettime(CLOCK_MONOTONIC, &tp);
>+			nexttime = tp.tv_sec;
>+			nexttime = nexttime * 1000000 + tp.tv_nsec / 1000 +
>+			    RELOADDELAY;
>+		} else
>+			sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL);
>+
>+		/*
>+		 * If a reload is pending, poll for received request(s),
>+		 * otherwise set a RELOADDELAY timeout, since a SIGHUP
>+		 * could be processed between the got_sighup test and
>+		 * the select() system call.
>+		 */
>+		tv.tv_sec = 0;
>+		if (got_sighup)
>+			tv.tv_usec = 0;
>+		else
>+			tv.tv_usec = RELOADDELAY;
> 		readfds = svc_fdset;
>-		switch (select(svc_maxfd + 1, &readfds, NULL, NULL, NULL)) {
>+		switch (select(svc_maxfd + 1, &readfds, NULL, NULL, &tv)) {
> 		case -1:
>-			if (errno == EINTR)
>+			if (errno == EINTR) {
>+				/* Allow a reload now. */
>+				nexttime = 0;
>                                 continue;
>+			}
> 			syslog(LOG_ERR, "mountd died: select: %m");
> 			exit(1);
> 		case 0:
>+			/* Allow a reload now. */
>+			nexttime = 0;
> 			continue;
> 		default:
> 			svc_getreqset(&readfds);

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Attachments on bug 246597: 215182 | 215283