Attachment 93989 Details for Bug 74773 – Fix handling of mmap failure and mapping empty files

[patch] Fix handling of mmap failure and mapping empty files

Fix-handling-of-mmap-failure-and-mapping-empty-fil.patch (text/plain), 2.04 KB, created by Stef Walter on 2014-02-13 07:25:46 UTC

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Creator: Stef Walter

Created: 2014-02-13 07:25:46 UTC

Size: 2.04 KB

patch

obsolete

>From 44beedb8c2b4e30b421b604fb1b044402a1d1ff6 Mon Sep 17 00:00:00 2001
>From: Pascal Terjan <pterjan@google.com>
>Date: Sun, 9 Feb 2014 23:39:20 +0000
>Subject: [PATCH] Fix handling of mmap failure and mapping empty files
>
>Check the return value of mmap() correctly.
>
>Empty files cannot be mmap'd so we implement some
>work around code for that.
>
>https://bugs.freedesktop.org/show_bug.cgi?id=74773
>
>Signed-off-by: Stef Walter <stef@thewalter.net>
>---
> common/compat.c            | 11 +++++++++--
> common/tests/test-compat.c | 17 +++++++++++++++++
> 2 files changed, 26 insertions(+), 2 deletions(-)
>
>diff --git a/common/compat.c b/common/compat.c
>index 9aa556a..f5b88ec 100644
>--- a/common/compat.c
>+++ b/common/compat.c
>@@ -216,9 +216,15 @@ p11_mmap_open (const char *path,
> 		return NULL;
> 	}
> 
>+	if (sb->st_size == 0) {
>+		*data = "";
>+		*size = 0;
>+		return map;
>+	}
>+
> 	map->size = sb->st_size;
> 	map->data = mmap (NULL, map->size, PROT_READ, MAP_PRIVATE, map->fd, 0);
>-	if (map->data == NULL) {
>+	if (map->data == MAP_FAILED) {
> 		close (map->fd);
> 		free (map);
> 		return NULL;
>@@ -232,7 +238,8 @@ p11_mmap_open (const char *path,
> void
> p11_mmap_close (p11_mmap *map)
> {
>-	munmap (map->data, map->size);
>+	if (map->size)
>+		munmap (map->data, map->size);
> 	close (map->fd);
> 	free (map);
> }
>diff --git a/common/tests/test-compat.c b/common/tests/test-compat.c
>index 872170d..42471ae 100644
>--- a/common/tests/test-compat.c
>+++ b/common/tests/test-compat.c
>@@ -83,6 +83,22 @@ test_getauxval (void)
> 	free (path);
> }
> 
>+static void
>+test_mmap (void)
>+{
>+	p11_mmap *map;
>+	void *data;
>+	size_t size;
>+	char file[] = "emptyfileXXXXXX";
>+	int fd = mkstemp (file);
>+	close (fd);
>+	/* mmap on empty file should work */
>+	map = p11_mmap_open (file, NULL, &data, &size);
>+	unlink (file);
>+	assert_ptr_not_null (map);
>+	p11_mmap_close (map);
>+}
>+
> #endif /* OS_UNIX */
> 
> int
>@@ -95,6 +111,7 @@ main (int argc,
> 	if (!getenv ("FAKED_MODE")) {
> 		p11_test (test_getauxval, "/compat/getauxval");
> 	}
>+	p11_test (test_mmap, "/compat/mmap");
> #endif
> 	return p11_test_run (argc, argv);
> }
>-- 
>1.8.5.3

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