From: Wu Fengguang <fengguang.wu@xxxxxxxxx>
The O_* bit numbers are defined in 20+ arch/*, and can silently overlap.
Add a compile time check to ensure the uniqueness as suggested by David
Miller.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: Roland Dreier <rdreier@xxxxxxxxx>
Cc: Jamie Lokier <jamie@xxxxxxxxxxxxx>
Cc: Andreas Schwab <schwab@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/fcntl.c | 15 +++++++++++++--
include/asm-generic/fcntl.h | 4 ++++
2 files changed, 17 insertions(+), 2 deletions(-)
diff -puN fs/fcntl.c~vfs-o_-bit-numbers-uniqueness-check fs/fcntl.c
--- a/fs/fcntl.c~vfs-o_-bit-numbers-uniqueness-check
+++ a/fs/fcntl.c
@@ -767,11 +767,22 @@ void kill_fasync(struct fasync_struct **
}
EXPORT_SYMBOL(kill_fasync);
-static int __init fasync_init(void)
+static int __init fcntl_init(void)
{
+ /* please add new bits here to ensure allocation uniqueness */
+ BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
+ O_RDONLY | O_WRONLY | O_RDWR |
+ O_CREAT | O_EXCL | O_NOCTTY |
+ O_TRUNC | O_APPEND | O_NONBLOCK |
+ __O_SYNC | O_DSYNC | FASYNC |
+ O_DIRECT | O_LARGEFILE | O_DIRECTORY |
+ O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
+ FMODE_EXEC
+ ));
+
fasync_cache = kmem_cache_create("fasync_cache",
sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
return 0;
}
-module_init(fasync_init)
+module_init(fcntl_init)
diff -puN include/asm-generic/fcntl.h~vfs-o_-bit-numbers-uniqueness-check include/asm-generic/fcntl.h
--- a/include/asm-generic/fcntl.h~vfs-o_-bit-numbers-uniqueness-check
+++ a/include/asm-generic/fcntl.h
@@ -11,6 +11,10 @@
* -Eric Paris
*/
+/*
+ * When introducing new O_* bits, please check its uniqueness in fcntl_init().
+ */
+
#define O_ACCMODE 00000003
#define O_RDONLY 00000000
#define O_WRONLY 00000001
_
--
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