Reset SIGPIPE signal handler in child process before exec().

Ignored signals, such as SIGPIPE in Mutt, are inherited by child
processes.  This can cause incorrect behavior in filter-like programs
that expect SIGPIPE to be the default value of "Term".

A couple other places in Mutt already reset SIGTERM, SIGTSTP, and
SIGCONT, with a comment mentioning it really wasn't necessary.  Since
I don't much like messing with signals, I'll leave those resets in.

Extract those plus SIGPIPE into a new function,
mutt_reset_child_signals() and add that before each exec call.

Thanks to Vincent Lefèvre for reporting the issue and for the initial
patch, which this commit is based upon.

1 files changed, 1 insertions, 0 deletions

diff --git a/filter.c b/filter.c
index a49eb271..0dab2f93 100644
--- a/filter.c
+++ b/filter.c
@@ -85,6 +85,7 @@ mutt_create_filter_fd (const char *cmd, FILE **in, FILE **out, FILE **err,
   if ((thepid = fork ()) == 0)
   {
     mutt_unblock_signals_system (0);
+    mutt_reset_child_signals ();
 
     if (in)
     {