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authorShawn O. Pearce <spearce@spearce.org>2007-03-06 20:44:37 -0500
committerJunio C Hamano <junkio@cox.net>2007-03-07 11:15:26 -0800
commitdc49cd769b5fa6b7e0114b051c34a849828a7603 (patch)
tree7eafafcd36ab731599da3fb5e59d3f4379c342d3 /diffcore-order.c
parent6777a59fcdfd96b9ca5cba49cb265c6c47de3d02 (diff)
downloadgit-dc49cd769b5fa6b7e0114b051c34a849828a7603.tar.gz
Cast 64 bit off_t to 32 bit size_t
Some systems have sizeof(off_t) == 8 while sizeof(size_t) == 4. This implies that we are able to access and work on files whose maximum length is around 2^63-1 bytes, but we can only malloc or mmap somewhat less than 2^32-1 bytes of memory. On such a system an implicit conversion of off_t to size_t can cause the size_t to wrap, resulting in unexpected and exciting behavior. Right now we are working around all gcc warnings generated by the -Wshorten-64-to-32 option by passing the off_t through xsize_t(). In the future we should make xsize_t on such problematic platforms detect the wrapping and die if such a file is accessed. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'diffcore-order.c')
-rw-r--r--diffcore-order.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/diffcore-order.c b/diffcore-order.c
index 7ad0946185..2a4bd8232e 100644
--- a/diffcore-order.c
+++ b/diffcore-order.c
@@ -14,6 +14,7 @@ static void prepare_order(const char *orderfile)
void *map;
char *cp, *endp;
struct stat st;
+ size_t sz;
if (order)
return;
@@ -25,11 +26,12 @@ static void prepare_order(const char *orderfile)
close(fd);
return;
}
- map = mmap(NULL, st.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
+ sz = xsize_t(st.st_size);
+ map = mmap(NULL, sz, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
return;
- endp = (char *) map + st.st_size;
+ endp = (char *) map + sz;
for (pass = 0; pass < 2; pass++) {
cnt = 0;
cp = map;