Re: [PATCH] http-backend: Don't infinite loop during die()

[Junio C Hamano <gitster@pobox.com>]

"Shawn O. Pearce" <spearce@spearce.org> writes:

> If stdout has already been closed by the CGI and die() gets called,
> the CGI will fail to write the "Status: 500 Internal Server Error" to
> the pipe, which results in die() being called again (via safe_write).
> This goes on in an infinite loop until the stack overflows and the
> process is killed by SIGSEGV.
>
> Instead set a flag on the first die() invocation and perform no
> action during recursive die() calls.  This way failures to write the
> error messages to the stdout pipe do not result in an infinite loop.

Hmm.  I would need something like this on top, but there must be a better
way.  Ideas?

-- >8 --
Subject: [PATCH] fixup! http-backend.c: Don't infinite loop

Now die_webcgi() actually can return during a recursive call into it,
causing

    http-backend.c:554: error: 'noreturn' function does return

Work it around with a somewhat ugly workaround.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 http-backend.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/http-backend.c b/http-backend.c
index f4d49b6..d3ec6f0 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -536,7 +536,7 @@ static void service_rpc(char *service_name)
 	strbuf_release(&buf);
 }
 
-static NORETURN void die_webcgi(const char *err, va_list params)
+static void die_webcgi(const char *err, va_list params)
 {
 	static int dead;
 
@@ -606,7 +606,7 @@ int main(int argc, char **argv)
 	int i;
 
 	git_extract_argv0_path(argv[0]);
-	set_die_routine(die_webcgi);
+	set_die_routine((void *)die_webcgi);
 
 	if (!method)
 		die("No REQUEST_METHOD from server");
-- 
1.7.0.3.435.g097f4