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[PATCH] read-cache.c: do not die if mmap fails

From
Varun Naik <vcnaik94@gmail.com>
Date
Jul 14, 2019, 03:01 UTC
Message-ID
<20190714030153.22022-1-vcnaik94@gmail.com>

do_read_index() mmaps the index, or tries to die with an error message on failure. It should call xmmap_gently(), which returns MAP_FAILED, rather than xmmap(), which dies with its own error message.

An easy way to cause this mmap to fail is by setting $GIT_INDEX_FILE to a path to a directory and then invoking any command that reads from the index.

Signed-off-by: Varun Naik <vcnaik94@gmail.com>
---
I believe this is the only place that calls xmmap() when it should be
calling xmmap_gently(). There is a related recent commit 3203566a71
("Use xmmap_gently instead of xmmap in use_pack", 2019-05-16).
 read-cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/read-cache.c b/read-cache.c
index 22e7b9944e..4e30dafa9d 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -2140,7 +2140,7 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 	if (mmap_size < sizeof(struct cache_header) + the_hash_algo->rawsz)
 		die(_("%s: index file smaller than expected"), path);
 
-	mmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	mmap = xmmap_gently(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
 	if (mmap == MAP_FAILED)
 		die_errno(_("%s: unable to map index file"), path);
 	close(fd);
-- 
2.22.0
Next: Junio C Hamano
Message 1 of 2 in “read-cache.c: do not die if mmap fails”
  1. read-cache.c: do not die if mmap failsVarun Naik, Jul 14, 2019
  2. Junio C HamanoJul 14, 2019

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