From: Willy Tarreau <w@1wt.eu>
Date: Fri, 1 Mar 2019 09:21:55 +0000 (+0100)
Subject: BUG/MINOR: mworker: be careful to restore the original rlim_fd_cur/max on reload
X-Git-Tag: v2.0-dev2~137
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8dca19549ab3b30342b92b56b2c766a6a4ec8d0e;p=thirdparty%2Fhaproxy.git

BUG/MINOR: mworker: be careful to restore the original rlim_fd_cur/max on reload

When the master re-execs itself on reload, it doesn't restore the initial
rlim_fd_cur/rlim_fd_max values, which have been modified by the ulimit-n
or global maxconn directives. This is a problem, because if these values
were set really low it could prevent the process from restarting, and if
they were set very high, this could have some implications on the restart
time, or later on the computed maxconn.

Let's simply reset these values to the ones we had at boot to maintain
the system in a consistent state.

A backport could be performed to 1.9 and maybe 1.8. This patch depends on
the two previous ones.
---

diff --git a/src/haproxy.c b/src/haproxy.c
index 0d42bc0b75..40865f0a36 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -716,6 +716,7 @@ void mworker_reload()
 	int next_argc = 0;
 	int j;
 	char *msg = NULL;
+	struct rlimit limit;
 	struct per_thread_deinit_fct *ptdf;
 
 	mworker_block_signals();
@@ -739,6 +740,16 @@ void mworker_reload()
 	if (fdtab)
 		deinit_pollers();
 
+	/* restore the initial FD limits */
+	limit.rlim_cur = rlim_fd_cur_at_boot;
+	limit.rlim_max = rlim_fd_max_at_boot;
+	if (setrlimit(RLIMIT_NOFILE, &limit) == -1) {
+		getrlimit(RLIMIT_NOFILE, &limit);
+		ha_warning("Failed to restore initial FD limits (cur=%u max=%u), using cur=%u max=%u\n",
+			   rlim_fd_cur_at_boot, rlim_fd_max_at_boot,
+			   (unsigned int)limit.rlim_cur, (unsigned int)limit.rlim_max);
+	}
+
 	/* compute length  */
 	while (next_argv[next_argc])
 		next_argc++;