* process.c (before_exec, after_exec): change SIGPIPE handler to SIG_DFL

  before calling execve(). Because r31760 reintroduced an issue that
  system() may hang up (i.e. [ruby-dev:12261]).
* process.c (save_sigpipe, restore_sigpipe): new.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31761 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 29 insertions, 7 deletions

diff --git a/process.c b/process.c
index 0f60cfb940..af55a0e412 100644
--- a/process.c
+++ b/process.c
@@ -984,14 +984,41 @@ void rb_thread_reset_timer_thread(void);
 
 static int forked_child = 0;
 
+#ifdef SIGPIPE
+static RETSIGTYPE (*saved_sigpipe_handler)(int) = 0;
+#endif
+
+#if defined(POSIX_SIGNAL)
+# define signal(a,b) posix_signal((a),(b))
+#endif
+
+static void save_sigpipe(void)
+{
+#ifdef SIGPIPE
+    /*
+     * Some OS commands don't initialize signal handler properly. Thus we have to
+     * reset signal handler before exec(). Otherwise, system() and similar child process
+     * interaction might fail. (e.g. ruby -e "system 'yes | ls'") [ruby-dev:12261]
+     */
+    saved_sigpipe_handler = signal(SIGPIPE, SIG_DFL);
+#endif
+}
+
+static void restore_sigpipe(void)
+{
+#ifdef SIGPIPE
+    signal(SIGPIPE, saved_sigpipe_handler);
+#endif
+}
+
 /*
  * On old MacOS X, exec() may return ENOTSUPP if the process have multiple threads.
  * Therefore we have to kill internal threads at once. [ruby-core: 10583]
  */
 #define before_exec() \
-    (rb_enable_interrupt(), (void)(forked_child ? 0 : (rb_thread_stop_timer_thread(), 1)))
+    (rb_enable_interrupt(), save_sigpipe(), (void)(forked_child ? 0 : (rb_thread_stop_timer_thread(), 1)))
 #define after_exec() \
-  (rb_thread_reset_timer_thread(), rb_thread_start_timer_thread(), forked_child = 0, rb_disable_interrupt())
+    (rb_thread_reset_timer_thread(), rb_thread_start_timer_thread(), forked_child = 0, restore_sigpipe(), rb_disable_interrupt())
 #define before_fork() before_exec()
 #define after_fork() (GET_THREAD()->thrown_errinfo = 0, after_exec())
 
@@ -2907,11 +2934,6 @@ rb_f_abort(int argc, VALUE *argv)
     return Qnil;		/* not reached */
 }
 
-
-#if defined(POSIX_SIGNAL)
-# define signal(a,b) posix_signal((a),(b))
-#endif
-
 void
 rb_syswait(rb_pid_t pid)
 {