[PATCH v2] upload-pack: use buffered I/O to talk to rev-list

From

René Scharfe <l.s.r@web.de>

Date

Aug 12, 2020, 16:52 UTC

Message-ID

<cf395005-af63-f698-fe19-6c4b6f1a8a4b@web.de>

In-Reply-To

<6722ade6-971e-7ecc-e8f0-7f595ca0b0ff@web.de>

Helped-by: Chris Torek <chris.torek@gmail.com>
Helped-by: Johannes Sixt <j6t@kdbg.org>
---
Changes since v1:
- Handle fprintf() errors immediately.
- Call ferror() and fflush() explicitly before calling fclose().
- Ignore fclose() errors, similar to the original code.
- Initialize the stream pointer and use a NULL check in the error
  handler to avoid a bogus compiler warning about it being used
  without initialization.

 upload-pack.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/upload-pack.c b/upload-pack.c
index 80ad9a38d81..811fdd47b58 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -603,9 +603,8 @@ static int do_reachable_revlist(struct child_process *cmd,
 		"rev-list", "--stdin", NULL,
 	};
 	struct object *o;
-	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
+	FILE *cmd_in = NULL;
 	int i;
-	const unsigned hexsz = the_hash_algo->hexsz;

 	cmd->argv = argv;
 	cmd->git_cmd = 1;
@@ -623,8 +622,8 @@ static int do_reachable_revlist(struct child_process *cmd,
 	if (start_command(cmd))
 		goto error;

-	namebuf[0] = '^';
-	namebuf[hexsz + 1] = '\n';
+	cmd_in = xfdopen(cmd->in, "w");
+
 	for (i = get_max_object_index(); 0 < i; ) {
 		o = get_indexed_object(--i);
 		if (!o)
@@ -633,11 +632,9 @@ static int do_reachable_revlist(struct child_process *cmd,
 			o->flags &= ~TMP_MARK;
 		if (!is_our_ref(o, allow_uor))
 			continue;
-		memcpy(namebuf + 1, oid_to_hex(&o->oid), hexsz);
-		if (write_in_full(cmd->in, namebuf, hexsz + 2) < 0)
+		if (fprintf(cmd_in, "^%s\n", oid_to_hex(&o->oid)) < 0)
 			goto error;
 	}
-	namebuf[hexsz] = '\n';
 	for (i = 0; i < src->nr; i++) {
 		o = src->objects[i].item;
 		if (is_our_ref(o, allow_uor)) {
@@ -647,11 +644,12 @@ static int do_reachable_revlist(struct child_process *cmd,
 		}
 		if (reachable && o->type == OBJ_COMMIT)
 			o->flags |= TMP_MARK;
-		memcpy(namebuf, oid_to_hex(&o->oid), hexsz);
-		if (write_in_full(cmd->in, namebuf, hexsz + 1) < 0)
+		if (fprintf(cmd_in, "%s\n", oid_to_hex(&o->oid)) < 0)
 			goto error;
 	}
-	close(cmd->in);
+	if (ferror(cmd_in) || fflush(cmd_in))
+		goto error;
+	fclose(cmd_in);
 	cmd->in = -1;
 	sigchain_pop(SIGPIPE);

@@ -660,8 +658,8 @@ static int do_reachable_revlist(struct child_process *cmd,
 error:
 	sigchain_pop(SIGPIPE);

-	if (cmd->in >= 0)
-		close(cmd->in);
+	if (cmd_in)
+		fclose(cmd_in);
 	if (cmd->out >= 0)
 		close(cmd->out);
 	return -1;
--
2.28.0