aboutsummaryrefslogtreecommitdiff
path: root/fs/fcntl.c
diff options
context:
space:
mode:
authorAl Viro <viro@zeniv.linux.org.uk>2008-04-23 20:38:10 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2008-04-25 09:24:05 -0400
commitf8f95702f0c4529b0f59488f4509608f0c160e77 (patch)
tree618c1ed56eb48da11189f1db9216dd92750c9812 /fs/fcntl.c
parent3b1253880b7a9e6db54b943b2d40bcf2202f58ab (diff)
downloadlinux-linaro-f8f95702f0c4529b0f59488f4509608f0c160e77.tar.gz
[PATCH] sanitize locate_fd()
* 'file' argument is unused; lose it. * move setting flags from the caller (dupfd()) to locate_fd(); pass cloexec flag as new argument. Note that files_fdtable() that used to be in dupfd() isn't needed in the place in locate_fd() where the moved code ends up - we know that ->file_lock hadn't been dropped since the last time we calculated fdt because we can get there only if expand_files() returns 0 and it doesn't drop/reacquire in that case. * move getting/dropping ->file_lock into locate_fd(). Now the caller doesn't need to do anything with files_struct *files anymore and we can move that inside locate_fd() as well, killing the struct files_struct * argument. At that point locate_fd() is extremely similar to get_unused_fd_flags() and the next patches will merge those two. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/fcntl.c')
-rw-r--r--fs/fcntl.c40
1 files changed, 14 insertions, 26 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index e632da761fc..3f3ac630ccd 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -55,14 +55,16 @@ static int get_close_on_exec(unsigned int fd)
* file_lock held for write.
*/
-static int locate_fd(struct files_struct *files,
- struct file *file, unsigned int orig_start)
+static int locate_fd(unsigned int orig_start, int cloexec)
{
+ struct files_struct *files = current->files;
unsigned int newfd;
unsigned int start;
int error;
struct fdtable *fdt;
+ spin_lock(&files->file_lock);
+
error = -EINVAL;
if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
goto out;
@@ -97,42 +99,28 @@ repeat:
if (error)
goto repeat;
- /*
- * We reacquired files_lock, so we are safe as long as
- * we reacquire the fdtable pointer and use it while holding
- * the lock, no one can free it during that time.
- */
if (start <= files->next_fd)
files->next_fd = newfd + 1;
+ FD_SET(newfd, fdt->open_fds);
+ if (cloexec)
+ FD_SET(newfd, fdt->close_on_exec);
+ else
+ FD_CLR(newfd, fdt->close_on_exec);
error = newfd;
-
+
out:
+ spin_unlock(&files->file_lock);
return error;
}
static int dupfd(struct file *file, unsigned int start, int cloexec)
{
- struct files_struct * files = current->files;
- struct fdtable *fdt;
- int fd;
-
- spin_lock(&files->file_lock);
- fd = locate_fd(files, file, start);
- if (fd >= 0) {
- /* locate_fd() may have expanded fdtable, load the ptr */
- fdt = files_fdtable(files);
- FD_SET(fd, fdt->open_fds);
- if (cloexec)
- FD_SET(fd, fdt->close_on_exec);
- else
- FD_CLR(fd, fdt->close_on_exec);
- spin_unlock(&files->file_lock);
+ int fd = locate_fd(start, cloexec);
+ if (fd >= 0)
fd_install(fd, file);
- } else {
- spin_unlock(&files->file_lock);
+ else
fput(file);
- }
return fd;
}