[PATCH 1/2] Make xmalloc and xrealloc thread-safe

[Fredrik Kuivinen <frekui@gmail.com>]

Signed-off-by: Fredrik Kuivinen <frekui@gmail.com>
---

 builtin/grep.c         |    2 +-
 builtin/pack-objects.c |    4 ++--
 git-compat-util.h      |    8 ++++++++
 preload-index.c        |    2 +-
 run-command.c          |    3 ++-
 wrapper.c              |   22 ++++++++++++++++------
 6 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/builtin/grep.c b/builtin/grep.c
index 9d30ddb..78b0bf4 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -236,7 +236,7 @@ static void start_threads(struct grep_opt *opt)
 		struct grep_opt *o = grep_opt_dup(opt);
 		o->output = strbuf_out;
 		compile_grep_patterns(o);
-		err = pthread_create(&threads[i], NULL, run, o);
+		err = xpthread_create(&threads[i], NULL, run, o);
 
 		if (err)
 			die("grep: failed to create thread: %s",
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 9780258..022b6a8 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1651,8 +1651,8 @@ static void ll_find_deltas(struct object_entry **list, unsigned list_size,
 			continue;
 		pthread_mutex_init(&p[i].mutex, NULL);
 		pthread_cond_init(&p[i].cond, NULL);
-		ret = pthread_create(&p[i].thread, NULL,
-				     threaded_find_deltas, &p[i]);
+		ret = xpthread_create(&p[i].thread, NULL,
+				      threaded_find_deltas, &p[i]);
 		if (ret)
 			die("unable to create thread: %s", strerror(ret));
 		active_threads++;
diff --git a/git-compat-util.h b/git-compat-util.h
index aebd9cd..fe10901 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -140,6 +140,10 @@ extern char *gitbasename(char *);
 #include <openssl/err.h>
 #endif
 
+#ifndef NO_PTHREADS
+#include <pthread.h>
+#endif
+
 /* On most systems <limits.h> would have given us this, but
  * not on some systems (e.g. GNU/Hurd).
  */
@@ -356,6 +360,10 @@ static inline void *gitmempcpy(void *dest, const void *src, size_t n)
 
 extern void release_pack_memory(size_t, int);
 
+#ifndef NO_PTHREADS
+extern int xpthread_create(pthread_t *thread, const pthread_attr_t *attr,
+			   void *(*start_routine)(void*), void *arg);
+#endif
 extern char *xstrdup(const char *str);
 extern void *xmalloc(size_t size);
 extern void *xmallocz(size_t size);
diff --git a/preload-index.c b/preload-index.c
index e3d0bda..250bb0b 100644
--- a/preload-index.c
+++ b/preload-index.c
@@ -86,7 +86,7 @@ static void preload_index(struct index_state *index, const char **pathspec)
 		p->offset = offset;
 		p->nr = work;
 		offset += work;
-		if (pthread_create(&p->pthread, NULL, preload_thread, p))
+		if (xpthread_create(&p->pthread, NULL, preload_thread, p))
 			die("unable to create threaded lstat");
 	}
 	for (i = 0; i < threads; i++) {
diff --git a/run-command.c b/run-command.c
index e996b21..1e4def4 100644
--- a/run-command.c
+++ b/run-command.c
@@ -568,7 +568,8 @@ int start_async(struct async *async)
 	async->proc_in = proc_in;
 	async->proc_out = proc_out;
 	{
-		int err = pthread_create(&async->tid, NULL, run_thread, async);
+		int err = xpthread_create(&async->tid, NULL, run_thread,
+					  async);
 		if (err) {
 			error("cannot create thread: %s", strerror(err));
 			goto error;
diff --git a/wrapper.c b/wrapper.c
index 9c71b21..e7140d1 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -15,19 +15,29 @@ char *xstrdup(const char *str)
 	return ret;
 }
 
+static int multiple_threads;
+#ifndef NO_PTHREADS
+int xpthread_create(pthread_t *thread, const pthread_attr_t *attr,
+		    void *(*start_routine)(void*), void *arg)
+{
+	multiple_threads = 1;
+	return pthread_create(thread, attr, start_routine, arg);
+}
+#endif
+
 void *xmalloc(size_t size)
 {
 	void *ret = malloc(size);
 	if (!ret && !size)
 		ret = malloc(1);
-	if (!ret) {
+	if (!ret && !multiple_threads) {
 		release_pack_memory(size, -1);
 		ret = malloc(size);
 		if (!ret && !size)
 			ret = malloc(1);
-		if (!ret)
-			die("Out of memory, malloc failed");
 	}
+	if (!ret)
+		die("Out of memory, malloc failed");
 #ifdef XMALLOC_POISON
 	memset(ret, 0xA5, size);
 #endif
@@ -66,14 +76,14 @@ void *xrealloc(void *ptr, size_t size)
 	void *ret = realloc(ptr, size);
 	if (!ret && !size)
 		ret = realloc(ptr, 1);
-	if (!ret) {
+	if (!ret && !multiple_threads) {
 		release_pack_memory(size, -1);
 		ret = realloc(ptr, size);
 		if (!ret && !size)
 			ret = realloc(ptr, 1);
-		if (!ret)
-			die("Out of memory, realloc failed");
 	}
+	if (!ret)
+		die("Out of memory, realloc failed");
 	return ret;
 }