curl: initialize and cleanup global curl state

pks-t · pks-t · commit 8c1c14bc35d5 · 2018-02-28T12:07:31.000Z
The documentation of curl states that any program making use of libcurl
is responsible for calling `curl_global_init` previous to using any
curl functions, and `curl_global_cleanup` when the program is about to
terminate. We currently call neither. While this seems to work just
fine, Valgrind may complain about unfree'd memory.

Fix the issue by correctly setting up and tearing down libcurl.
diff --git a/src/global.c b/src/global.c
@@ -11,6 +11,7 @@
 #include "sysdir.h"
 #include "filter.h"
 #include "merge_driver.h"
+#include "streams/curl.h"
 #include "streams/openssl.h"
 #include "thread-utils.h"
 #include "git2/global.h"
@@ -23,7 +24,7 @@
 
 git_mutex git__mwindow_mutex;
 
-#define MAX_SHUTDOWN_CB 9
+#define MAX_SHUTDOWN_CB 10
 
 static git_global_shutdown_fn git__shutdown_callbacks[MAX_SHUTDOWN_CB];
 static git_atomic git__n_shutdown_callbacks;
@@ -63,7 +64,8 @@ static int init_common(void)
 		(ret = git_filter_global_init()) == 0 &&
 		(ret = git_merge_driver_global_init()) == 0 &&
 		(ret = git_transport_ssh_global_init()) == 0 &&
-		(ret = git_openssl_stream_global_init()) == 0)
+		(ret = git_openssl_stream_global_init()) == 0 &&
+		(ret = git_curl_stream_global_init()) == 0)
 		ret = git_mwindow_global_init();
 
 	GIT_MEMORY_BARRIER;
diff --git a/src/streams/curl.c b/src/streams/curl.c
@@ -14,6 +14,7 @@
 #include "stream.h"
 #include "git2/transport.h"
 #include "buffer.h"
+#include "global.h"
 #include "vector.h"
 #include "proxy.h"
 
@@ -38,6 +39,17 @@ typedef struct {
 	git_cred *proxy_cred;
 } curl_stream;
 
+int git_curl_stream_global_init(void)
+{
+	if (curl_global_init(CURL_GLOBAL_ALL) != 0) {
+		giterr_set(GITERR_NET, "could not initialize curl");
+		return -1;
+	}
+
+	git__on_shutdown(curl_global_cleanup);
+	return 0;
+}
+
 static int seterr_curl(curl_stream *s)
 {
 	giterr_set(GITERR_NET, "curl error: %s\n", s->curl_error);
diff --git a/src/streams/curl.h b/src/streams/curl.h
@@ -11,6 +11,7 @@
 
 #include "git2/sys/stream.h"
 
+extern int git_curl_stream_global_init(void);
 extern int git_curl_stream_new(git_stream **out, const char *host, const char *port);
 
 #endif
