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Better fix for the empty notification issue #4242

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Merged
martinpitt merged 2 commits into from
Sep 29, 2016
Merged

Better fix for the empty notification issue #4242

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b292283
pid1: process zero-length notification messages again
keszybz Sep 29, 2016
6bd74eb
pid1: more informative error message for ignored notifications
keszybz Sep 29, 2016
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25 changes: 14 additions & 11 deletions src/core/manager.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1657,13 +1657,12 @@ 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, const 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) {
Expand All @@ -1673,8 +1672,14 @@ static void manager_invoke_notify_message(Manager *m, Unit *u, pid_t pid, const

if (UNIT_VTABLE(u)->notify_message)
UNIT_VTABLE(u)->notify_message(u, pid, tags, fds);
else
log_unit_debug(u, "Got notification message for unit. Ignoring.");
else if (_unlikely_(log_get_max_level() >= LOG_DEBUG)) {
_cleanup_free_ char *x = NULL, *y = NULL;

x = cescape(buf);
if (x)
y = ellipsize(x, 20, 90);
log_unit_debug(u, "Got notification message \"%s\", ignoring.", strnull(y));
}
}

static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
Expand Down Expand Up @@ -1721,10 +1726,6 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t

return -errno;
}
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) {
Expand Down Expand Up @@ -1760,25 +1761,27 @@ 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_cgroup(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, PID_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, PID_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;
}

Expand Down