From c7bcd6cf1967e401225c3d6057e0ee62cdc29f8c Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>

Date: Thu, 29 Sep 2016 16:06:02 +0200

Subject: [PATCH] pid1: process zero-length notification messages again

This undoes 531ac2b234. I acked that patch without looking at the code

carefully enough. There are two problems:

- we want to process the fds anyway

- in principle empty notification messages are valid, and we should

  process them as usual, including logging using log_unit_debug().

Cherry-picked from: 8523bf7dd514a3a2c6114b7b8fb8f308b4f09fc4

Resolves: #1380259

Cherry-picked from: a86b767

Resolves: #1380259

---

 src/core/manager.c | 15 ++++++---------

 1 file changed, 6 insertions(+), 9 deletions(-)

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

index ed81059554..0376c4d4b4 100644

--- a/src/core/manager.c

+++ b/src/core/manager.c

@@ -1614,13 +1614,12 @@ static int manager_dispatch_cgroups_agent_fd(sd_event_source *source, int fd, ui

         return 0;

 }

-static void manager_invoke_notify_message(Manager *m, Unit *u, pid_t pid, char *buf, size_t n, FDSet *fds) {

+static void manager_invoke_notify_message(Manager *m, Unit *u, pid_t pid, const char *buf, FDSet *fds) {

         _cleanup_strv_free_ char **tags = NULL;

         assert(m);

         assert(u);

         assert(buf);

-        assert(n > 0);

         tags = strv_split(buf, "\n\r");

         if (!tags) {

@@ -1682,10 +1681,6 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t

                  * example... */

                 return 0;

         }

-        if (n == 0) {

-                log_debug("Got zero-length notification message. Ignoring.");

-                return 0;

-        }

         CMSG_FOREACH(cmsg, &msghdr) {

                 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {

@@ -1722,25 +1717,27 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t

                 return 0;

         }

+        /* The message should be a string. Here we make sure it's NUL-terminated,

+         * but only the part until first NUL will be used anyway. */

         buf[n] = 0;

         /* Notify every unit that might be interested, but try

          * to avoid notifying the same one multiple times. */

         u1 = manager_get_unit_by_pid(m, ucred->pid);

         if (u1) {

-                manager_invoke_notify_message(m, u1, ucred->pid, buf, n, fds);

+                manager_invoke_notify_message(m, u1, ucred->pid, buf, fds);

                 found = true;

         }

         u2 = hashmap_get(m->watch_pids1, LONG_TO_PTR(ucred->pid));

         if (u2 && u2 != u1) {

-                manager_invoke_notify_message(m, u2, ucred->pid, buf, n, fds);

+                manager_invoke_notify_message(m, u2, ucred->pid, buf, fds);

                 found = true;

         }

         u3 = hashmap_get(m->watch_pids2, LONG_TO_PTR(ucred->pid));

         if (u3 && u3 != u2 && u3 != u1) {

-                manager_invoke_notify_message(m, u3, ucred->pid, buf, n, fds);

+                manager_invoke_notify_message(m, u3, ucred->pid, buf, fds);

                 found = true;

         }