From af49c6d0918bf04aad89bd885a4eef5767a33d0e Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 24 Sep 2015 17:05:45 -0400 Subject: add reentrant variants of sha1_to_hex and find_unique_abbrev The sha1_to_hex and find_unique_abbrev functions always write into reusable static buffers. There are a few problems with this: - future calls overwrite our result. This is especially annoying with find_unique_abbrev, which does not have a ring of buffers, so you cannot even printf() a result that has two abbreviated sha1s. - if you want to put the result into another buffer, we often strcpy, which looks suspicious when auditing for overflows. This patch introduces sha1_to_hex_r and find_unique_abbrev_r, which write into a user-provided buffer. Of course this is just punting on the overflow-auditing, as the buffer obviously needs to be GIT_SHA1_HEXSZ + 1 bytes. But it is much easier to audit, since that is a well-known size. We retain the non-reentrant forms, which just become thin wrappers around the reentrant ones. This patch also adds a strbuf variant of find_unique_abbrev, which will be handy in later patches. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- hex.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'hex.c') diff --git a/hex.c b/hex.c index 899b74a08..0519f853b 100644 --- a/hex.c +++ b/hex.c @@ -61,12 +61,10 @@ int get_oid_hex(const char *hex, struct object_id *oid) return get_sha1_hex(hex, oid->hash); } -char *sha1_to_hex(const unsigned char *sha1) +char *sha1_to_hex_r(char *buffer, const unsigned char *sha1) { - static int bufno; - static char hexbuffer[4][GIT_SHA1_HEXSZ + 1]; static const char hex[] = "0123456789abcdef"; - char *buffer = hexbuffer[3 & ++bufno], *buf = buffer; + char *buf = buffer; int i; for (i = 0; i < GIT_SHA1_RAWSZ; i++) { @@ -79,6 +77,13 @@ char *sha1_to_hex(const unsigned char *sha1) return buffer; } +char *sha1_to_hex(const unsigned char *sha1) +{ + static int bufno; + static char hexbuffer[4][GIT_SHA1_HEXSZ + 1]; + return sha1_to_hex_r(hexbuffer[3 & ++bufno], sha1); +} + char *oid_to_hex(const struct object_id *oid) { return sha1_to_hex(oid->hash); -- cgit v1.2.1