From a3b8feb9320f745f960fe8f7006183137f4969b1 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Mon, 2 Nov 2015 09:34:05 +0100

Subject: [PATCH] core: bump net.unix.max_dgram_qlen really early during boot

Only that way it actually has an effect on all our sockets, including

$NOTIFY_SOCKET.

(cherry picked from commit 19854865a877a3a4fa3d04550c15a99c0e1187ff)

Related: #1267707

---

 src/core/main.c  | 36 ++++++++++++++++++++++++++++++++++++

 src/shared/def.h |  3 +++

 2 files changed, 39 insertions(+)

diff --git a/src/core/main.c b/src/core/main.c

index 60ea36c3cb..c9d8ce4a40 100644

--- a/src/core/main.c

+++ b/src/core/main.c

@@ -1198,6 +1198,7 @@ static int status_welcome(void) {

 static int write_container_id(void) {

         const char *c;

+        int r;

         c = getenv("container");

         if (isempty(c))

@@ -1206,6 +1207,40 @@ static int write_container_id(void) {

         return write_string_file("/run/systemd/container", c);

 }

+static int bump_unix_max_dgram_qlen(void) {

+        _cleanup_free_ char *qlen = NULL;

+        unsigned long v;

+        int r;

+

+        /* Let's bump the net.unix.max_dgram_qlen sysctl. The kernel

+         * default of 16 is simply too low. We set the value really

+         * really early during boot, so that it is actually applied to

+         * all our sockets, including the $NOTIFY_SOCKET one. */

+

+        r = read_one_line_file("/proc/sys/net/unix/max_dgram_qlen", &qlen);

+        if (r < 0)

+                return log_warning_errno(r, "Failed to read AF_UNIX datagram queue length, ignoring: %m");

+

+        r = safe_atolu(qlen, &v);

+        if (r < 0)

+                return log_warning_errno(r, "Failed to parse AF_UNIX datagram queue length, ignoring: %m");

+

+        if (v >= DEFAULT_UNIX_MAX_DGRAM_QLEN)

+                return 0;

+

+        free(qlen);

+        qlen = NULL;

+        if (asprintf(&qlen, "%lu\n", DEFAULT_UNIX_MAX_DGRAM_QLEN) < 0)

+                return log_oom();

+

+        r = write_string_file("/proc/sys/net/unix/max_dgram_qlen", qlen);

+        if (r < 0)

+                return log_full_errno(IN_SET(r, -EROFS, -EPERM, -EACCES) ? LOG_DEBUG : LOG_WARNING, r,

+                                      "Failed to bump AF_UNIX datagram queue length, ignoring: %m");

+

+        return 1;

+}

+

 int main(int argc, char *argv[]) {

         Manager *m = NULL;

         int r, retval = EXIT_FAILURE;

@@ -1571,6 +1606,7 @@ int main(int argc, char *argv[]) {

                 hostname_setup();

                 machine_id_setup(NULL);

                 loopback_setup();

+                bump_unix_max_dgram_qlen();

                 test_mtab();

                 test_usr();

diff --git a/src/shared/def.h b/src/shared/def.h

index a3d9fcf388..76daf012d7 100644

--- a/src/shared/def.h

+++ b/src/shared/def.h

@@ -35,6 +35,9 @@

  * the watchdog pings will keep the loop busy. */

 #define DEFAULT_EXIT_USEC (30*USEC_PER_SEC)

+/* The default value for the net.unix.max_dgram_qlen sysctl */

+#define DEFAULT_UNIX_MAX_DGRAM_QLEN 512UL

+

 #define SYSTEMD_CGROUP_CONTROLLER "name=systemd"

 #define SIGNALS_CRASH_HANDLER SIGSEGV,SIGILL,SIGFPE,SIGBUS,SIGQUIT,SIGABRT