http*: copy string returned by sha1_to_hex

In the fetch_index implementations in http-push.c and http-walker.c,
the string returned by sha1_to_hex is assumed to stay immutable.

This patch ensures that hex stays immutable by copying the string
returned by sha1_to_hex (via xstrdup) and frees it subsequently. It
also refactors free()'s and fclose()'s with labels.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 47 insertions, 45 deletions

diff --git a/http-push.c b/http-push.c
index 64c9bb0f90..82018009f3 100644
--- a/http-push.c
+++ b/http-push.c
@@ -958,7 +958,8 @@ static int add_send_request(struct object *obj, struct remote_lock *lock)
 
 static int fetch_index(unsigned char *sha1)
 {
-	char *hex = sha1_to_hex(sha1);
+	int ret = 0;
+	char *hex = xstrdup(sha1_to_hex(sha1));
 	char *filename;
 	char *url;
 	char tmpfile[PATH_MAX];
@@ -980,18 +981,18 @@ static int fetch_index(unsigned char *sha1)
 	if (start_active_slot(slot)) {
 		run_active_slot(slot);
 		if (results.curl_result != CURLE_OK) {
-			free(url);
-			return error("Unable to verify pack %s is available",
-				     hex);
+			ret = error("Unable to verify pack %s is available",
+				    hex);
+			goto cleanup_pack;
 		}
 	} else {
-		free(url);
-		return error("Unable to start request");
+		ret = error("Unable to start request");
+		goto cleanup_pack;
 	}
 
 	if (has_pack_index(sha1)) {
-		free(url);
-		return 0;
+		ret = 0;
+		goto cleanup_pack;
 	}
 
 	if (push_verbosely)
@@ -1003,9 +1004,9 @@ static int fetch_index(unsigned char *sha1)
 	snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 	indexfile = fopen(tmpfile, "a");
 	if (!indexfile) {
-		free(url);
-		return error("Unable to open local file %s for pack index",
-			     tmpfile);
+		ret = error("Unable to open local file %s for pack index",
+			    tmpfile);
+		goto cleanup_pack;
 	}
 
 	slot = get_active_slot();
@@ -1036,24 +1037,24 @@ static int fetch_index(unsigned char *sha1)
 	if (start_active_slot(slot)) {
 		run_active_slot(slot);
 		if (results.curl_result != CURLE_OK) {
-			free(url);
-			fclose(indexfile);
-			slot->local = NULL;
-			return error("Unable to get pack index %s\n%s", url,
-				     curl_errorstr);
+			ret = error("Unable to get pack index %s\n%s", url,
+				    curl_errorstr);
+			goto cleanup_index;
 		}
 	} else {
-		free(url);
-		fclose(indexfile);
-		slot->local = NULL;
-		return error("Unable to start request");
+		ret = error("Unable to start request");
+		goto cleanup_index;
 	}
 
-	free(url);
+	ret = move_temp_to_file(tmpfile, filename);
+
+cleanup_index:
 	fclose(indexfile);
 	slot->local = NULL;
-
-	return move_temp_to_file(tmpfile, filename);
+cleanup_pack:
+	free(url);
+	free(hex);
+	return ret;
 }
 
 static int setup_index(unsigned char *sha1)
diff --git a/http-walker.c b/http-walker.c
index bbc3023e40..d6cc622e96 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -371,7 +371,8 @@ static void prefetch(struct walker *walker, unsigned char *sha1)
 
 static int fetch_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 {
-	char *hex = sha1_to_hex(sha1);
+	int ret = 0;
+	char *hex = xstrdup(sha1_to_hex(sha1));
 	char *filename;
 	char *url;
 	char tmpfile[PATH_MAX];
@@ -394,18 +395,18 @@ static int fetch_index(struct walker *walker, struct alt_base *repo, unsigned ch
 	if (start_active_slot(slot)) {
 		run_active_slot(slot);
 		if (results.curl_result != CURLE_OK) {
-			free(url);
-			return error("Unable to verify pack %s is available",
+			ret = error("Unable to verify pack %s is available",
 				     hex);
+			goto cleanup_pack;
 		}
 	} else {
-		free(url);
-		return error("Unable to start request");
+		ret = error("Unable to start request");
+		goto cleanup_pack;
 	}
 
 	if (has_pack_index(sha1)) {
-		free(url);
-		return 0;
+		ret = 0;
+		goto cleanup_pack;
 	}
 
 	if (walker->get_verbosely)
@@ -417,9 +418,9 @@ static int fetch_index(struct walker *walker, struct alt_base *repo, unsigned ch
 	snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 	indexfile = fopen(tmpfile, "a");
 	if (!indexfile) {
-		free(url);
-		return error("Unable to open local file %s for pack index",
-			     tmpfile);
+		ret = error("Unable to open local file %s for pack index",
+			    tmpfile);
+		goto cleanup_pack;
 	}
 
 	slot = get_active_slot();
@@ -450,24 +451,24 @@ static int fetch_index(struct walker *walker, struct alt_base *repo, unsigned ch
 	if (start_active_slot(slot)) {
 		run_active_slot(slot);
 		if (results.curl_result != CURLE_OK) {
-			free(url);
-			fclose(indexfile);
-			slot->local = NULL;
-			return error("Unable to get pack index %s\n%s", url,
-				     curl_errorstr);
+			ret = error("Unable to get pack index %s\n%s", url,
+				    curl_errorstr);
+			goto cleanup_index;
 		}
 	} else {
-		free(url);
-		fclose(indexfile);
-		slot->local = NULL;
-		return error("Unable to start request");
+		ret = error("Unable to start request");
+		goto cleanup_index;
 	}
 
-	free(url);
+	ret = move_temp_to_file(tmpfile, filename);
+
+cleanup_index:
 	fclose(indexfile);
 	slot->local = NULL;
-
-	return move_temp_to_file(tmpfile, filename);
+cleanup_pack:
+	free(url);
+	free(hex);
+	return ret;
 }
 
 static int setup_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)