On Thu, 2010-03-11 at 14:11 -0800, akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> 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.
Until the FMODE_ and O_ bits do not overload I think we need to check
FMODE_EXEC and FMODE_NONOTIFY (if you have that one) inside fcntl_init()
as well. I guess I'll send a patch to someone ?Al? to add FMODE_EXEC to
the list....
-Eric
>
> 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 | 14 ++++++++++++--
> include/asm-generic/fcntl.h | 2 ++
> 2 files changed, 14 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
> @@ -739,11 +739,21 @@ 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(17 != 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
> + ));
> +
> 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
> @@ -4,6 +4,8 @@
> #include <linux/types.h>
>
> /*
> + * When introducing new O_* bits, please check its uniqueness in fcntl_init().
> + *
> * FMODE_EXEC is 0x20
> * FMODE_NONOTIFY is 0x1000000
> * These cannot be used by userspace O_* until internal and external open
> _
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