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authorShawn O. Pearce <spearce@spearce.org>2007-03-07 01:44:37 (GMT)
committerJunio C Hamano <junkio@cox.net>2007-03-07 19:15:26 (GMT)
commitdc49cd769b5fa6b7e0114b051c34a849828a7603 (patch)
tree7eafafcd36ab731599da3fb5e59d3f4379c342d3 /builtin-grep.c
parent6777a59fcdfd96b9ca5cba49cb265c6c47de3d02 (diff)
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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 'builtin-grep.c')
-rw-r--r--builtin-grep.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/builtin-grep.c b/builtin-grep.c
index e4f06f2..694da5b 100644
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -122,6 +122,8 @@ static int grep_file(struct grep_opt *opt, const char *filename)
struct stat st;
int i;
char *data;
+ size_t sz;
+
if (lstat(filename, &st) < 0) {
err_ret:
if (errno != ENOENT)
@@ -132,11 +134,12 @@ static int grep_file(struct grep_opt *opt, const char *filename)
return 0; /* empty file -- no grep hit */
if (!S_ISREG(st.st_mode))
return 0;
+ sz = xsize_t(st.st_size);
i = open(filename, O_RDONLY);
if (i < 0)
goto err_ret;
- data = xmalloc(st.st_size + 1);
- if (st.st_size != read_in_full(i, data, st.st_size)) {
+ data = xmalloc(sz + 1);
+ if (st.st_size != read_in_full(i, data, sz)) {
error("'%s': short read %s", filename, strerror(errno));
close(i);
free(data);
@@ -145,7 +148,7 @@ static int grep_file(struct grep_opt *opt, const char *filename)
close(i);
if (opt->relative && opt->prefix_length)
filename += opt->prefix_length;
- i = grep_buffer(opt, filename, data, st.st_size);
+ i = grep_buffer(opt, filename, data, sz);
free(data);
return i;
}