diff options
| -rw-r--r-- | fs/file.c | 44 | ||||
| -rw-r--r-- | fs/open.c | 44 |
2 files changed, 44 insertions, 44 deletions
diff --git a/fs/file.c b/fs/file.c index 4ce4a0fcf320..78cf88f2a0e8 100644 --- a/fs/file.c +++ b/fs/file.c @@ -569,3 +569,47 @@ int get_unused_fd_flags(unsigned flags) return __alloc_fd(current->files, 0, rlimit(RLIMIT_NOFILE), flags); } 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_open_fd(fd, fdt); + if (fd < files->next_fd) + files->next_fd = fd; +} + +void put_unused_fd(unsigned int fd) +{ + struct files_struct *files = current->files; + spin_lock(&files->file_lock); + __put_unused_fd(files, fd); + spin_unlock(&files->file_lock); +} + +EXPORT_SYMBOL(put_unused_fd); + +/* + * Install a file pointer in the fd array. + * + * The VFS is full of places where we drop the files lock between + * setting the open_fds bitmap and installing the file in the file + * array. At any such point, we are vulnerable to a dup2() race + * installing a file in the array before us. We need to detect this and + * fput() the struct file we are about to overwrite in this case. + * + * It should never happen - if we allow dup2() do it, _really_ bad things + * will follow. + */ + +void fd_install(unsigned int fd, struct file *file) +{ + struct files_struct *files = current->files; + struct fdtable *fdt; + spin_lock(&files->file_lock); + fdt = files_fdtable(files); + BUG_ON(fdt->fd[fd] != NULL); + rcu_assign_pointer(fdt->fd[fd], file); + spin_unlock(&files->file_lock); +} + +EXPORT_SYMBOL(fd_install); diff --git a/fs/open.c b/fs/open.c index e1f2cdb91a4d..c525bd0e65b6 100644 --- a/fs/open.c +++ b/fs/open.c @@ -803,50 +803,6 @@ struct file *dentry_open(const struct path *path, int flags, } EXPORT_SYMBOL(dentry_open); -static void __put_unused_fd(struct files_struct *files, unsigned int fd) -{ - struct fdtable *fdt = files_fdtable(files); - __clear_open_fd(fd, fdt); - if (fd < files->next_fd) - files->next_fd = fd; -} - -void put_unused_fd(unsigned int fd) -{ - struct files_struct *files = current->files; - spin_lock(&files->file_lock); - __put_unused_fd(files, fd); - spin_unlock(&files->file_lock); -} - -EXPORT_SYMBOL(put_unused_fd); - -/* - * Install a file pointer in the fd array. - * - * The VFS is full of places where we drop the files lock between - * setting the open_fds bitmap and installing the file in the file - * array. At any such point, we are vulnerable to a dup2() race - * installing a file in the array before us. We need to detect this and - * fput() the struct file we are about to overwrite in this case. - * - * It should never happen - if we allow dup2() do it, _really_ bad things - * will follow. - */ - -void fd_install(unsigned int fd, struct file *file) -{ - struct files_struct *files = current->files; - struct fdtable *fdt; - spin_lock(&files->file_lock); - fdt = files_fdtable(files); - BUG_ON(fdt->fd[fd] != NULL); - rcu_assign_pointer(fdt->fd[fd], file); - spin_unlock(&files->file_lock); -} - -EXPORT_SYMBOL(fd_install); - static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op) { int lookup_flags = 0; |