Re-enable SIGPIPE for children so they have default behaviour

3 files changed, 12 insertions, 0 deletions

diff --git a/src/lightdm.c b/src/lightdm.c
index 32ab3c05..610c5aee 100644
--- a/src/lightdm.c
+++ b/src/lightdm.c
@@ -1214,6 +1214,12 @@ main (int argc, char **argv)
     };
     GError *error = NULL;
 
+    /* Disable the SIGPIPE handler - this is a stupid Unix hangover behaviour.
+     * We will handle piples / sockets being closed instead of having the whole daemon be killed...
+     * http://stackoverflow.com/questions/8369506/why-does-sigpipe-exist
+     */
+    signal (SIGPIPE, SIG_IGN);
+
     /* When lightdm starts sessions it needs to run itself in a new mode */
     if (argc >= 2 && strcmp (argv[1], "--session-child") == 0)
         return session_child_run (argc, argv);
diff --git a/src/process.c b/src/process.c
index d9b7eb9a..75357db6 100644
--- a/src/process.c
+++ b/src/process.c
@@ -236,6 +236,9 @@ process_start (Process *process, gboolean block)
         for (i = 0; i < env_length; i++)
             setenv (env_keys[i], env_values[i], TRUE);
 
+        /* Reset SIGPIPE handler so the child has default behaviour (we disabled it at LightDM start) */
+        signal (SIGPIPE, SIG_DFL);
+
         execvp (argv[0], argv);
         _exit (EXIT_FAILURE);
     }
diff --git a/src/session-child.c b/src/session-child.c
index e393ce4c..fb12d9b8 100644
--- a/src/session-child.c
+++ b/src/session-child.c
@@ -704,6 +704,9 @@ session_child_run (int argc, char **argv)
             }
         }
 
+        /* Reset SIGPIPE handler so the child has default behaviour (we disabled it at LightDM start) */
+        signal (SIGPIPE, SIG_DFL);
+
         /* Run the command */
         execve (command_argv[0], command_argv, pam_getenvlist (pam_handle));
         _exit (EXIT_FAILURE);