diff options
| author | Petr Baudis <pasky@ucw.cz> | 2005-04-13 02:14:06 -0700 |
|---|---|---|
| committer | Petr Baudis <xpasky@machine> | 2005-04-13 02:14:06 -0700 |
| commit | 5c2a7fbc362e4227ced84c32c3fdc9682d085962 (patch) | |
| tree | 958b0946a5082fbc6797209fb225f5d7a786b786 /read-cache.c | |
| parent | 7912c07037cf704394e9bcb7cb24c05ee03aa921 (diff) | |
| download | git-5c2a7fbc362e4227ced84c32c3fdc9682d085962.tar.gz git-5c2a7fbc362e4227ced84c32c3fdc9682d085962.tar.xz | |
[PATCH] SHA1 naive collision checking
When compiled with -DCOLLISION_CHECK, we will check against SHA1
collisions when writing to the object database.
From: Christopher Li <chrislgit@chrisli.org>
Signed-off-by: Petr Baudis <pasky@ucw.cz>
Diffstat (limited to 'read-cache.c')
| -rw-r--r-- | read-cache.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/read-cache.c b/read-cache.c index 545369446..2ee96bc92 100644 --- a/read-cache.c +++ b/read-cache.c @@ -216,8 +216,25 @@ int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size) int fd; fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666); - if (fd < 0) - return (errno == EEXIST) ? 0 : -1; + if (fd < 0) { + void *map; + static int error(const char * string); + + if (errno != EEXIST) + return -1; +#ifndef COLLISION_CHECK + fd = open(filename, O_RDONLY); + if (fd < 0) + return -1; + map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); + if (map == MAP_FAILED) + return -1; + if (memcmp(buf, map, size)) + return error("SHA1 collision detected!" + " This is bad, bad, BAD!\a\n"); +#endif + return 0; + } write(fd, buf, size); close(fd); return 0; |