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From: Doan Tran Cong Danh <congdanhqx@gmail.com>
To: git@vger.kernel.org
Cc: peff@peff.net, Doan Tran Cong Danh <congdanhqx@gmail.com>,
	Johannes Sixt <j6t@kdbg.org>,
	Johannes Schindelin <Johannes.Schindelin@gmx.de>
Subject: [PATCH v2 3/3] mingw: use {gm,local}time_s as backend for {gm,local}time_r
Date: Thu, 28 Nov 2019 19:25:05 +0700
Message-ID: <33a67eb37702172a6ff29215a840d2cf925daab8.1574943677.git.congdanhqx@gmail.com> (raw)
In-Reply-To: <cover.1574943677.git.congdanhqx@gmail.com>

Since Windows doesn't provide gmtime_r(3) and localtime_r(3),
we're providing a compat version by using non-reentrant gmtime(3) and
localtime(3) as backend. Then, we copy the returned data into the
buffer.

By doing that, in case of failure, we will dereference a NULL pointer
returned by gmtime(3), and localtime(3), and we always return a valid
pointer instead of NULL.

Drop the memcpy(3) by using gmtime_s, and localtime_s as backend on
Windows, and make sure we will return NULL in case of failure.

Cc: Johannes Sixt <j6t@kdbg.org>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com>
---
 compat/mingw.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index fe609239dd..75695a24a3 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -986,16 +986,16 @@ int pipe(int filedes[2])
 
 struct tm *gmtime_r(const time_t *timep, struct tm *result)
 {
-	/* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */
-	memcpy(result, gmtime(timep), sizeof(struct tm));
-	return result;
+	if (gmtime_s(result, timep) == 0)
+		return result;
+	return NULL;
 }
 
 struct tm *localtime_r(const time_t *timep, struct tm *result)
 {
-	/* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */
-	memcpy(result, localtime(timep), sizeof(struct tm));
-	return result;
+	if (localtime_s(result, timep) == 0)
+		return result;
+	return NULL;
 }
 
 char *mingw_getcwd(char *pointer, int len)
-- 
2.24.0.615.g37f5bfbdea


      parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-27 15:13 [PATCH 0/5] drop non-reentrant time usage Doan Tran Cong Danh
2019-11-27 15:13 ` [PATCH 1/5] date.c::datestamp: switch to reentrant localtime_r Doan Tran Cong Danh
2019-11-27 15:13 ` [PATCH 2/5] date.c::time_to_tm_local: use reentrant localtime_r(3) Doan Tran Cong Danh
2019-11-27 15:13 ` [PATCH 3/5] date.c::time_to_tm: use reentrant gmtime_r(3) Doan Tran Cong Danh
2019-11-27 15:13 ` [PATCH 4/5] archive-zip: use reentrant localtime_r(3) Doan Tran Cong Danh
2019-11-27 15:13 ` [PATCH 5/5] mingw: use {gm,local}time_s as backend for {gm,local}time_r Doan Tran Cong Danh
2019-11-27 19:35   ` Johannes Schindelin
2019-11-27 19:39   ` Johannes Schindelin
2019-11-28 12:05     ` Danh Doan
2019-11-27 16:29 ` [PATCH 0/5] drop non-reentrant time usage Jeff King
2019-11-28 12:16   ` Danh Doan
2019-11-28 12:25 ` [PATCH v2 0/3] Phase out non-reentrant time functions Doan Tran Cong Danh
2019-11-28 12:25   ` [PATCH v2 1/3] date.c: switch to reentrant {gm,local}time_r Doan Tran Cong Danh
2019-11-28 12:25   ` [PATCH v2 2/3] archive-zip.c: switch to reentrant localtime_r Doan Tran Cong Danh
2019-11-28 12:25   ` Doan Tran Cong Danh [this message]

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