diff options
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 54 |
1 files changed, 24 insertions, 30 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 2fc11f2e2b21..efb618fc8ffe 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -840,36 +840,6 @@ static int copy_io(unsigned long clone_flags, struct task_struct *tsk) return 0; } -/* - * Helper to unshare the files of the current task. - * We don't want to expose copy_files internals to - * the exec layer of the kernel. - */ - -int unshare_files(void) -{ - struct files_struct *files = current->files; - struct files_struct *newf; - int error = 0; - - BUG_ON(!files); - - /* This can race but the race causes us to copy when we don't - need to and drop the copy */ - if(atomic_read(&files->count) == 1) - { - atomic_inc(&files->count); - return 0; - } - newf = dup_fd(files, &error); - if (newf) { - task_lock(current); - current->files = newf; - task_unlock(current); - } - return error; -} - static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) { struct sighand_struct *sig; @@ -1807,3 +1777,27 @@ bad_unshare_cleanup_thread: bad_unshare_out: return err; } + +/* + * Helper to unshare the files of the current task. + * We don't want to expose copy_files internals to + * the exec layer of the kernel. + */ + +int unshare_files(struct files_struct **displaced) +{ + struct task_struct *task = current; + struct files_struct *copy; + int error; + + error = unshare_fd(CLONE_FILES, ©); + if (error || !copy) { + *displaced = NULL; + return error; + } + *displaced = task->files; + task_lock(task); + task->files = copy; + task_unlock(task); + return 0; +} |