From: Rich Felker <dalias@aerifal.cx>
Date: Sat, 6 Dec 2014 02:19:39 +0000 (-0500)
Subject: use direct syscall rather than write function in posix_spawn child
X-Git-Tag: v1.1.6~36
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=8f7bc690f07e90177b176b6e19736ad7c1d49840;p=oweals%2Fmusl.git

use direct syscall rather than write function in posix_spawn child

the write function is a cancellation point and accesses thread-local
state belonging to the calling thread in the parent process. since
cancellation is blocked for the duration of posix_spawn, this is
probably safe, but it's fragile and unnecessary. making the syscall
directly is just as easy and clearly safe.
---

diff --git a/src/process/posix_spawn.c b/src/process/posix_spawn.c
index af127317..0bdf71cd 100644
--- a/src/process/posix_spawn.c
+++ b/src/process/posix_spawn.c
@@ -136,7 +136,7 @@ static int child(void *args_vp)
 fail:
 	/* Since sizeof errno < PIPE_BUF, the write is atomic. */
 	ret = -ret;
-	if (ret) while (write(p, &ret, sizeof ret) < 0);
+	if (ret) while (__syscall(SYS_write, p, &ret, sizeof ret) < 0);
 	_exit(127);
 }