[vte] pty: Simplify signal handling

[Christian Persch <chpe src gnome org>]

commit 171b8aae9e8cd9555ad86d8a293e50f5ee74cd61
Author: Christian Persch <chpe gnome org>
Date:   Mon Dec 7 22:51:08 2015 +0100

    pty: Simplify signal handling
    
    Unblock all signals at the start of the child setup, and
    iterate through the signals by number instead of the #ifdef
    hell.

 src/pty.cc |  119 +++++++-----------------------------------------------------
 1 files changed, 14 insertions(+), 105 deletions(-)
---
diff --git a/src/pty.cc b/src/pty.cc
index f93739a..2a00481 100644
--- a/src/pty.cc
+++ b/src/pty.cc
@@ -45,6 +45,7 @@
 #include <sys/syslimits.h>
 #endif
 #include <signal.h>
+#include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -79,107 +80,6 @@
 
 #define I_(string) (g_intern_static_string(string))
 
-/* Reset the handlers for all known signals to their defaults.  The parent
- * (or one of the libraries it links to) may have changed one to be ignored. */
-static void
-_vte_pty_reset_signal_handlers(void)
-{
-#ifdef SIGHUP
-       signal(SIGHUP,  SIG_DFL);
-#endif
-       signal(SIGINT,  SIG_DFL);
-       signal(SIGQUIT, SIG_DFL);
-       signal(SIGILL,  SIG_DFL);
-       signal(SIGABRT, SIG_DFL);
-       signal(SIGFPE,  SIG_DFL);
-#ifdef SIGKILL
-       signal(SIGKILL, SIG_DFL);
-#endif
-       signal(SIGSEGV, SIG_DFL);
-#ifdef SIGPIPE
-       signal(SIGPIPE, SIG_DFL);
-#endif
-#ifdef SIGALRM
-       signal(SIGALRM, SIG_DFL);
-#endif
-       signal(SIGTERM, SIG_DFL);
-#ifdef SIGCHLD
-       signal(SIGCHLD, SIG_DFL);
-#endif
-#ifdef SIGCONT
-       signal(SIGCONT, SIG_DFL);
-#endif
-#ifdef SIGSTOP
-       signal(SIGSTOP, SIG_DFL);
-#endif
-#ifdef SIGTSTP
-       signal(SIGTSTP, SIG_DFL);
-#endif
-#ifdef SIGTTIN
-       signal(SIGTTIN, SIG_DFL);
-#endif
-#ifdef SIGTTOU
-       signal(SIGTTOU, SIG_DFL);
-#endif
-#ifdef SIGBUS
-       signal(SIGBUS,  SIG_DFL);
-#endif
-#ifdef SIGPOLL
-       signal(SIGPOLL, SIG_DFL);
-#endif
-#ifdef SIGPROF
-       signal(SIGPROF, SIG_DFL);
-#endif
-#ifdef SIGSYS
-       signal(SIGSYS,  SIG_DFL);
-#endif
-#ifdef SIGTRAP
-       signal(SIGTRAP, SIG_DFL);
-#endif
-#ifdef SIGURG
-       signal(SIGURG,  SIG_DFL);
-#endif
-#ifdef SIGVTALARM
-       signal(SIGVTALARM, SIG_DFL);
-#endif
-#ifdef SIGXCPU
-       signal(SIGXCPU, SIG_DFL);
-#endif
-#ifdef SIGXFSZ
-       signal(SIGXFSZ, SIG_DFL);
-#endif
-#ifdef SIGIOT
-       signal(SIGIOT,  SIG_DFL);
-#endif
-#ifdef SIGEMT
-       signal(SIGEMT,  SIG_DFL);
-#endif
-#ifdef SIGSTKFLT
-       signal(SIGSTKFLT, SIG_DFL);
-#endif
-#ifdef SIGIO
-       signal(SIGIO,   SIG_DFL);
-#endif
-#ifdef SIGCLD
-       signal(SIGCLD,  SIG_DFL);
-#endif
-#ifdef SIGPWR
-       signal(SIGPWR,  SIG_DFL);
-#endif
-#ifdef SIGINFO
-       signal(SIGINFO, SIG_DFL);
-#endif
-#ifdef SIGLOST
-       signal(SIGLOST, SIG_DFL);
-#endif
-#ifdef SIGWINCH
-       signal(SIGWINCH, SIG_DFL);
-#endif
-#ifdef SIGUNUSED
-       signal(SIGUNUSED, SIG_DFL);
-#endif
-}
-
 typedef struct _VtePtyPrivate VtePtyPrivate;
 
 typedef struct {
@@ -224,6 +124,19 @@ vte_pty_child_setup (VtePty *pty)
         VtePtyPrivate *priv = pty->priv;
        VtePtyChildSetupData *data = &priv->child_setup_data;
 
+        /* Unblock all signals */
+        sigset_t set;
+        sigemptyset(&set);
+        if (pthread_sigmask(SIG_SETMASK, &set, nullptr) == -1) {
+                _vte_debug_print(VTE_DEBUG_PTY, "Failed to unblock signals: %m");
+                _exit(127);
+        }
+
+        /* Reset the handlers for all signals to their defaults.  The parent
+         * (or one of the libraries it links to) may have changed one to be ignored. */
+        for (int n = 1; n < SIGUNUSED; n++)
+                signal(n, SIG_DFL);
+
         int masterfd = priv->pty_fd;
         if (masterfd == -1)
                 _exit(127);
@@ -312,10 +225,6 @@ vte_pty_child_setup (VtePty *pty)
                close(fd);
        }
 
-       /* Reset our signals -- our parent may have done any number of
-        * weird things to them. */
-       _vte_pty_reset_signal_handlers();
-
         /* Now set the TERM environment variable */
         /* FIXME: Setting environment here seems to have no effect, the merged envp2 will override on exec.
          * By the way, we'd need to set the one from there, if any. */