[PATCH 5/7] worktree: use xsize_t to access file size

[Jeff King <peff@peff.net>]

To read the "gitdir" file into memory, we stat the file and
allocate a buffer. But we store the size in an "int", which
may be truncated. We should use a size_t and xsize_t(),
which will detect truncation.

An overflow is unlikely for a "gitdir" file, but it's a good
practice to model.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/worktree.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/builtin/worktree.c b/builtin/worktree.c
index de26849f55..2f4a4ef9cd 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -38,7 +38,8 @@ static int prune_worktree(const char *id, struct strbuf *reason)
 {
 	struct stat st;
 	char *path;
-	int fd, len;
+	int fd;
+	size_t len;
 
 	if (!is_directory(git_path("worktrees/%s", id))) {
 		strbuf_addf(reason, _("Removing worktrees/%s: not a valid directory"), id);
@@ -56,7 +57,7 @@ static int prune_worktree(const char *id, struct strbuf *reason)
 			    id, strerror(errno));
 		return 1;
 	}
-	len = st.st_size;
+	len = xsize_t(st.st_size);
 	path = xmallocz(len);
 	read_in_full(fd, path, len);
 	close(fd);
-- 
2.14.1.1148.ga2561536a1