[PATCH v3 2/3] unpack-objects: add --max-input-size=<size> option

[Christian Couder <christian.couder@gmail.com>]

When receiving a pack-file, it can be useful to abort the
`git unpack-objects`, if the pack-file is too big.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 Documentation/git-unpack-objects.txt | 3 +++
 builtin/unpack-objects.c             | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/Documentation/git-unpack-objects.txt b/Documentation/git-unpack-objects.txt
index 3e887d1..b3de50d 100644
--- a/Documentation/git-unpack-objects.txt
+++ b/Documentation/git-unpack-objects.txt
@@ -44,6 +44,9 @@ OPTIONS
 --strict::
 	Don't write objects with broken content or links.
 
+--max-input-size=<size>::
+	Die, if the pack is larger than <size>.
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index 172470b..4532aa0 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -19,6 +19,7 @@ static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict]
 static unsigned char buffer[4096];
 static unsigned int offset, len;
 static off_t consumed_bytes;
+static off_t max_input_size;
 static git_SHA_CTX ctx;
 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
 
@@ -87,6 +88,8 @@ static void use(int bytes)
 	if (signed_add_overflows(consumed_bytes, bytes))
 		die("pack too large for current definition of off_t");
 	consumed_bytes += bytes;
+	if (max_input_size && consumed_bytes > max_input_size)
+		die(_("pack exceeds maximum allowed size"));
 }
 
 static void *get_data(unsigned long size)
@@ -550,6 +553,10 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 				len = sizeof(*hdr);
 				continue;
 			}
+			if (skip_prefix(arg, "--max-input-size=", &arg)) {
+				max_input_size = strtoumax(arg, NULL, 10);
+				continue;
+			}
 			usage(unpack_usage);
 		}
 
-- 
2.10.0.rc1.3.g93be2b9