[PATCH] Ignore SIGPIPE when running a filter driver

[Jehan Bing <jehan@orb.com>]

If a filter is not defined or if it fails, git behaves as if the filter
is a no-op passthru. However, if the filter exits before reading all
the content, and depending on the timing git, could be kill with
SIGPIPE instead.

Ignore SIGPIPE while processing the filter to detect when it exits
early and fallback to using the unfiltered content.

Signed-off-by: Jehan Bing <jehan@orb.com>
---
Since it's not really a problem in the "required-filter" patch but a
general one with filter drivers, I'm submitting this patch
independently. I'm also wording it as a pre-patch to "required-filter".

-Jehan

 convert.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/convert.c b/convert.c
index c06309f..5d312cb 100644
--- a/convert.c
+++ b/convert.c
@@ -2,6 +2,7 @@
 #include "attr.h"
 #include "run-command.h"
 #include "quote.h"
+#include "sigchain.h"
 
 /*
  * convert.c - convert a file when checking it out and checking it in.
@@ -360,12 +361,16 @@ static int filter_buffer(int in, int out, void *data)
 	if (start_command(&child_process))
 		return error("cannot fork to run external filter %s", params->cmd);
 
+	sigchain_push(SIGPIPE, SIG_IGN);
+
 	write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
 	if (close(child_process.in))
 		write_err = 1;
 	if (write_err)
 		error("cannot feed the input to external filter %s", params->cmd);
 
+	sigchain_pop(SIGPIPE);
+
 	status = finish_command(&child_process);
 	if (status)
 		error("external filter %s failed %d", params->cmd, status);
-- 
1.7.9