[PATCH] compat: let git_mmap use malloc(3) directly

From: René Scharfe <l.s.r@web.de>
Date: Aug 21, 2021, 12:52 UTC
Message-ID: <9c2fe5de-be23-3e66-6edf-3c2edfb804f3@web.de>

xmalloc() dies on error, allows zero-sized allocations and enforces GIT_ALLOC_LIMIT for testing. Our mmap replacement doesn't need any of that. Let's cut out the wrapper, reject zero-sized requests as required by POSIX and use malloc(3) directly. Allocation errors were needlessly handled by git_mmap() before; this code becomes reachable now.

Signed-off-by: René Scharfe <l.s.r@web.de>
---
 compat/mmap.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/compat/mmap.c b/compat/mmap.c
index 14d31010df..8d6c02d4bc 100644
--- a/compat/mmap.c
+++ b/compat/mmap.c
@@ -7,7 +7,12 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
 	if (start != NULL || flags != MAP_PRIVATE || prot != PROT_READ)
 		die("Invalid usage of mmap when built with NO_MMAP");

-	start = xmalloc(length);
+	if (length == 0) {
+		errno = EINVAL;
+		return MAP_FAILED;
+	}
+
+	start = malloc(length);
 	if (start == NULL) {
 		errno = ENOMEM;
 		return MAP_FAILED;
--
2.33.0