From 1084b845d9d77bcb2e8255636358dd0dc35360a5 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Tue, 2 Jan 2007 11:19:05 -0800
Subject: Fix infinite loop when deleting multiple packed refs.

It was stupid to link the same element twice to lock_file_list
and end up in a loop, so we certainly need a fix.

But it is not like we are taking a lock on multiple files in
this case.  It is just that we leave the linked element on the
list even after commit_lock_file() successfully removes the
cruft.

We cannot remove the list element in commit_lock_file(); if we
are interrupted in the middle of list manipulation, the call to
remove_lock_file_on_signal() will happen with a broken list
structure pointed by lock_file_list, which would cause the cruft
to remain, so not removing the list element is the right thing
to do.  Instead we should be reusing the element already on the
list.

There is already a code for that in lock_file() function in
lockfile.c.  The code checks lk->next and the element is linked
only when it is not already on the list -- which is incorrect
for the last element on the list (which has NULL in its next
field), but if you read the check as "is this element already on
the list?" it actually makes sense.  We do not want to link it
on the list again, nor we would want to set up signal/atexit
over and over.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/cache.h b/cache.h
index f2ec5c8..a0e9727 100644
--- a/cache.h
+++ b/cache.h
@@ -174,6 +174,7 @@ extern int refresh_cache(unsigned int flags);
 
 struct lock_file {
 	struct lock_file *next;
+	char on_list;
 	char filename[PATH_MAX];
 };
 extern int hold_lock_file_for_update(struct lock_file *, const char *path, int);
diff --git a/lockfile.c b/lockfile.c
index 2a2fea3..143d7d8 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -28,9 +28,12 @@ static int lock_file(struct lock_file *lk, const char *path)
 	sprintf(lk->filename, "%s.lock", path);
 	fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
 	if (0 <= fd) {
-		if (!lk->next) {
+		if (!lk->on_list) {
 			lk->next = lock_file_list;
 			lock_file_list = lk;
+			lk->on_list = 1;
+		}
+		if (lock_file_list) {
 			signal(SIGINT, remove_lock_file_on_signal);
 			atexit(remove_lock_file);
 		}
@@ -38,6 +41,8 @@ static int lock_file(struct lock_file *lk, const char *path)
 			return error("cannot fix permission bits on %s",
 				     lk->filename);
 	}
+	else
+		lk->filename[0] = 0;
 	return fd;
 }
 
diff --git a/refs.c b/refs.c
index 0e156c5..1549f2a 100644
--- a/refs.c
+++ b/refs.c
@@ -644,7 +644,6 @@ static int repack_without_ref(const char *refname)
 	}
 	if (!found)
 		return 0;
-	memset(&packlock, 0, sizeof(packlock));
 	fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 	if (fd < 0)
 		return error("cannot delete '%s' from packed refs", refname);
-- 
cgit v0.10.2-6-g49f6


From 8977c110b5bbd230c28c727ddb85856067d55cfb Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Wed, 3 Jan 2007 23:09:08 -0800
Subject: pack-check.c::verify_packfile(): don't run SHA-1 update on huge data

Running the SHA1_Update() on the whole packfile in a single call
revealed an overflow problem we had in the SHA-1 implementation
on POWER architecture some time ago, which was fixed with commit
b47f509b (June 19, 2006).  Other SHA-1 implementations may have
a similar problem.

The sliding mmap() series already makes chunked calls to
SHA1_Update(), so this patch itself will become moot when it
graduates to "master", but in the meantime, run the hash
function in smaller chunks to prevent possible future problems.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/pack-check.c b/pack-check.c
index c0caaee..8e123b7 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -1,16 +1,18 @@
 #include "cache.h"
 #include "pack.h"
 
+#define BATCH (1u<<20)
+
 static int verify_packfile(struct packed_git *p)
 {
 	unsigned long index_size = p->index_size;
 	void *index_base = p->index_base;
 	SHA_CTX ctx;
 	unsigned char sha1[20];
-	unsigned long pack_size = p->pack_size;
-	void *pack_base;
 	struct pack_header *hdr;
 	int nr_objects, err, i;
+	unsigned char *packdata;
+	unsigned long datasize;
 
 	/* Header consistency check */
 	hdr = p->pack_base;
@@ -25,11 +27,19 @@ static int verify_packfile(struct packed_git *p)
 			     "while idx size expects %d", nr_objects,
 			     num_packed_objects(p));
 
+	/* Check integrity of pack data with its SHA-1 checksum */
 	SHA1_Init(&ctx);
-	pack_base = p->pack_base;
-	SHA1_Update(&ctx, pack_base, pack_size - 20);
+	packdata = p->pack_base;
+	datasize = p->pack_size - 20;
+	while (datasize) {
+		unsigned long batch = (datasize < BATCH) ? datasize : BATCH;
+		SHA1_Update(&ctx, packdata, batch);
+		datasize -= batch;
+		packdata += batch;
+	}
 	SHA1_Final(sha1, &ctx);
-	if (hashcmp(sha1, (unsigned char *)pack_base + pack_size - 20))
+
+	if (hashcmp(sha1, (unsigned char *)(p->pack_base) + p->pack_size - 20))
 		return error("Packfile %s SHA1 mismatch with itself",
 			     p->pack_name);
 	if (hashcmp(sha1, (unsigned char *)index_base + index_size - 40))
-- 
cgit v0.10.2-6-g49f6