Attachment 215182 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), 2.26 KB, created by Rick Macklem on 2020-06-03 00:02:12 UTC

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Creator: Rick Macklem

Created: 2020-06-03 00:02:12 UTC

Size: 2.26 KB

patch

obsolete

>--- usr.sbin/mountd/mountd.c.reload	2020-06-02 16:22:42.032503000 -0700
>+++ usr.sbin/mountd/mountd.c	2020-06-02 16:45:21.706425000 -0700
>@@ -309,6 +309,12 @@ static struct pidfh *pfh = NULL;
> #define OP_MASKLEN	0x200
> #define OP_SEC		0x400
> 
>+/*
>+ * How long to delay a reload of exports when there are RPC request(s)
>+ * to process, in usec.
>+ */
>+#define	RELOADDELAY	250000
>+
> #ifdef DEBUG
> static int debug = 1;
> static void	SYSLOG(int, const char *, ...) __printflike(2, 3);
>@@ -413,6 +419,9 @@ 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;
>+	sigset_t sighup_mask;
> 
> 	/* Check that another mountd isn't already running. */
> 	pfh = pidfile_open(_PATH_MOUNTDPID, 0600, &otherpid);
>@@ -668,19 +677,47 @@ 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);
>+		gettimeofday(&tv, NULL);
>+		curtime = tv.tv_sec * 1000000 + tv.tv_usec;
>+		sigprocmask(SIG_BLOCK, &sighup_mask, NULL);
>+		if (got_sighup && curtime >= nexttime) {
> 			got_sighup = 0;
>-		}
>+			sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL);
>+			get_exportlist(1);
>+			gettimeofday(&tv, NULL);
>+			nexttime = tv.tv_sec * 1000000 + tv.tv_usec +
>+			    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