compat: make sure git_mmap is not expected to write

carenas · gitster · commit bf1e6da79157 · 2018-10-25T18:51:03.000+09:00
in f48000f ("Yank writing-back support from gitfakemmap.", 2005-10-08) support for writting back changes was removed but the specific prot flag that would be used was not checked for Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/compat/mmap.c b/compat/mmap.c
@@ -4,7 +4,7 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
 {
 	size_t n = 0;
 
-	if (start != NULL || !(flags & MAP_PRIVATE))
+	if (start != NULL || flags != MAP_PRIVATE || prot != PROT_READ)
 		die("Invalid usage of mmap when built with NO_MMAP");
 
 	start = xmalloc(length);

Original file line number	Diff line number	Diff line change
`@@ -4,7 +4,7 @@ void git_mmap(void start, size_t length, int prot, int flags, int fd, off_t of`
`4`	`4`	`{`
`5`	`5`	`size_t n = 0;`
`6`	`6`
`7`		`- if (start != NULL \|\| !(flags & MAP_PRIVATE))`
	`7`	`+ if (start != NULL \|\| flags != MAP_PRIVATE \|\| prot != PROT_READ)`
`8`	`8`	`die("Invalid usage of mmap when built with NO_MMAP");`
`9`	`9`
`10`	`10`	`start = xmalloc(length);`