mail.c: more robust handling of SIGCHLD

init: more robust signal handling

1 files changed, 7 insertions, 4 deletions

diff --git a/mailutils/mail.c b/mailutils/mail.c
index 71f46c86f..68883ff42 100644
--- a/mailutils/mail.c
+++ b/mailutils/mail.c
@@ -48,6 +48,12 @@ void FAST_FUNC launch_helper(const char **argv)
         xpipe(pipes);
         xpipe(pipes + 2);
 
+        // NB: handler must be installed before vfork
+        bb_signals(0
+                + (1 << SIGCHLD)
+                + (1 << SIGALRM)
+                , signal_handler);
+
         G.helper_pid = vfork();
         if (G.helper_pid < 0)
                 bb_perror_msg_and_die("vfork");
@@ -60,15 +66,12 @@ void FAST_FUNC launch_helper(const char **argv)
 
         if (!G.helper_pid) {
                 // child: try to execute connection helper
+                // NB: SIGCHLD & SIGALRM revert to SIG_DFL on exec
                 BB_EXECVP(*argv, (char **)argv);
                 _exit(127);
         }
 
         // parent
-        bb_signals(0
-                + (1 << SIGCHLD)
-                + (1 << SIGALRM)
-                , signal_handler);
         // check whether child is alive
         //redundant:signal_handler(SIGCHLD);
         // child seems OK -> parent goes on