On Wed, Dec 11, 2013 at 10:08:27PM +0100, Yann Droneaud wrote:
> close-on-exec flag is set by get_unused_fd_flags(), it makes
> sense to clear it in the opposite function, eg. put_unused_fd().
>
> Additionally, since the close_on_exec bit array is always initialized
> to 0, it can be safely assumed that any newly allocated file descriptor
> has close-on-exec flag not set, so there's no need to clear it
> explicitly.
>
> Signed-off-by: Yann Droneaud <ydroneaud@xxxxxxxxxx>
> ---
> fs/file.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/fs/file.c b/fs/file.c
> index 4a78f981557a..e98f5a5b1050 100644
> --- a/fs/file.c
> +++ b/fs/file.c
> @@ -500,8 +500,6 @@ repeat:
> __set_open_fd(fd, fdt);
> if (flags & O_CLOEXEC)
> __set_close_on_exec(fd, fdt);
> - else
> - __clear_close_on_exec(fd, fdt);
> error = fd;
> #if 1
> /* Sanity check */
> @@ -530,6 +528,7 @@ EXPORT_SYMBOL(get_unused_fd_flags);
> static void __put_unused_fd(struct files_struct *files, unsigned int fd)
> {
> struct fdtable *fdt = files_fdtable(files);
> + __clear_close_on_exec(fd, fdt);
> __clear_open_fd(fd, fdt);
> if (fd < files->next_fd)
> files->next_fd = fd;
> @@ -599,7 +598,6 @@ int __close_fd(struct files_struct *files, unsigned fd)
> if (!file)
> goto out_unlock;
> rcu_assign_pointer(fdt->fd[fd], NULL);
> - __clear_close_on_exec(fd, fdt);
> __put_unused_fd(files, fd);
> spin_unlock(&files->file_lock);
> return filp_close(file, files);
> @@ -625,7 +623,6 @@ void do_close_on_exec(struct files_struct *files)
> set = fdt->close_on_exec[i];
> if (!set)
> continue;
> - fdt->close_on_exec[i] = 0;
> for ( ; set ; fd++, set >>= 1) {
> struct file *file;
> if (!(set & 1))
> @@ -806,8 +803,6 @@ static int do_dup2(struct files_struct *files,
> __set_open_fd(fd, fdt);
> if (flags & O_CLOEXEC)
> __set_close_on_exec(fd, fdt);
> - else
> - __clear_close_on_exec(fd, fdt);
> spin_unlock(&files->file_lock);
>
> if (tofree)
>From my reading this will break at least the following:
fd = open(..., .. | O_CLOEXEC);
dup2(whatever, fd);
now fd has O_CLOEXEC even though it should not
--
Mateusz Guzik
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