[PATCH 2/3] Make res_init() thread safe.

[Sørensen, Kenneth]

>From c34c95553ac7ebd278059fada06319aaf132c906 Mon Sep 17 00:00:00 2001
From: Kenneth Soerensen <kenneth.sorensen at spectralink.com>
Date: Wed, 10 Apr 2013 16:52:52 +0200
Subject: [PATCH 2/3] Make res_init() thread safe.

res_init() was not atomic, which could give undesired behaviour. Now
res_init() is completely locked under one lock and the locking is
removed from __res_vinit().

Signed-off-by: Kenneth Soerensen <kenneth.sorensen at spectralink.com>
---
 libc/inet/resolv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index df6fefd..c230534 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -3434,7 +3434,6 @@ __res_vinit(res_state rp, int preinit)
 	int m = 0;
 #endif
 
-	__UCLIBC_MUTEX_LOCK(__resolv_lock);
 	__close_nameservers();
 	__open_nameservers();
 
@@ -3526,7 +3525,6 @@ __res_vinit(res_state rp, int preinit)
 
 	rp->options |= RES_INIT;
 
-	__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
 	return 0;
 }
 
@@ -3576,11 +3574,11 @@ res_init(void)
 	if (!_res.id)
 		_res.id = res_randomid();
 
-	__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
-
 	__res_vinit(&_res, 1);
 	__res_sync = res_sync_func;
 
+	__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
+
 	return 0;
 }
 libc_hidden_def(res_init)
@@ -3679,7 +3677,9 @@ struct __res_state *__resp = &_res;
 int
 res_ninit(res_state statp)
 {
+	__UCLIBC_MUTEX_LOCK(__resolv_lock);
 	return __res_vinit(statp, 0);
+	__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
 }
 
 #endif /* L_res_init */
-- 
1.8.1.4