[systemd-commits] 2 commits - TODO src/shared

[Lennart Poettering]

 TODO              |    2 ++
 src/shared/util.c |   35 +++++++++++++++++++++++------------
 2 files changed, 25 insertions(+), 12 deletions(-)

New commits:
commit eff3f4f9e92b56d9dfb90d5094e48cc743c776cc
Author: Lennart Poettering <lennart at poettering.net>
Date:   Wed Aug 27 21:43:33 2014 +0200

    update TODO

diff --git a/TODO b/TODO
index a00c13d..bc81a70 100644
--- a/TODO
+++ b/TODO
@@ -24,6 +24,8 @@ External:
 
 Features:
 
+* nspawn --network-interface= doesn't work...
+
 * dbus: add new message hdr field for allowing interactive auth, write spec for it. update dbus spec to mandate that unknown flags *must* be ignored...
 
 * maybe introduce AssertXYZ= similar to ConditionXYZ= that causes a unit to fail (instead of skipping it) if some condition is not true...

commit 8a7c93d858c342744adf481565d8bb03b9713dcf
Author: Lennart Poettering <lennart at poettering.net>
Date:   Wed Aug 27 21:42:20 2014 +0200

    util: fix minimal race where we might miss SIGTERMs when forking off an agent
    
    Before forking, block all signals, and unblock them afterwards. This way
    the child will have them blocked, and we won't lose them.

diff --git a/src/shared/util.c b/src/shared/util.c
index 9e4ff85..cf9d487 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -5102,9 +5102,9 @@ int fd_inc_rcvbuf(int fd, size_t n) {
 }
 
 int fork_agent(pid_t *pid, const int except[], unsigned n_except, const char *path, ...) {
-        pid_t parent_pid, agent_pid;
-        int fd;
         bool stdout_is_tty, stderr_is_tty;
+        pid_t parent_pid, agent_pid;
+        sigset_t ss, saved_ss;
         unsigned n, i;
         va_list ap;
         char **l;
@@ -5112,16 +5112,25 @@ int fork_agent(pid_t *pid, const int except[], unsigned n_except, const char *pa
         assert(pid);
         assert(path);
 
-        parent_pid = getpid();
-
         /* Spawns a temporary TTY agent, making sure it goes away when
          * we go away */
 
+        parent_pid = getpid();
+
+        /* First we temporarily block all signals, so that the new
+         * child has them blocked initially. This way, we can be sure
+         * that SIGTERMs are not lost we might send to the agent. */
+        assert_se(sigfillset(&ss) >= 0);
+        assert_se(sigprocmask(SIG_SETMASK, &ss, &saved_ss) >= 0);
+
         agent_pid = fork();
-        if (agent_pid < 0)
+        if (agent_pid < 0) {
+                assert_se(sigprocmask(SIG_SETMASK, &saved_ss, NULL) >= 0);
                 return -errno;
+        }
 
         if (agent_pid != 0) {
+                assert_se(sigprocmask(SIG_SETMASK, &saved_ss, NULL) >= 0);
                 *pid = agent_pid;
                 return 0;
         }
@@ -5132,24 +5141,26 @@ int fork_agent(pid_t *pid, const int except[], unsigned n_except, const char *pa
         if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
                 _exit(EXIT_FAILURE);
 
+        /* Make sure we actually can kill the agent, if we need to, in
+         * case somebody invoked us from a shell script that trapped
+         * SIGTERM or so... */
+        reset_all_signal_handlers();
+        reset_signal_mask();
+
         /* Check whether our parent died before we were able
-         * to set the death signal */
+         * to set the death signal and unblock the signals */
         if (getppid() != parent_pid)
                 _exit(EXIT_SUCCESS);
 
         /* Don't leak fds to the agent */
         close_all_fds(except, n_except);
 
-        /* Make sure we actually can kill the agent, if we need to, in
-         * case somebody invoked us from a shell script that trapped
-         * SIGTERM or so... */
-        reset_all_signal_handlers();
-        reset_signal_mask();
-
         stdout_is_tty = isatty(STDOUT_FILENO);
         stderr_is_tty = isatty(STDERR_FILENO);
 
         if (!stdout_is_tty || !stderr_is_tty) {
+                int fd;
+
                 /* Detach from stdout/stderr. and reopen
                  * /dev/tty for them. This is important to
                  * ensure that when systemctl is started via