3  *  linux/fs/file.c
17 #include <linux/file.h>
51  * space if any.  This does not copy the file pointers.  Called with the files
73  * Copy all file descriptors from the old table to the new, expanded table and
82 	cpy = ofdt->max_fds * sizeof(struct file *);  in copy_fdtable()
83 	set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);  in copy_fdtable()
117 	nr /= (1024 / sizeof(struct file *));  in alloc_fdtable()
119 	nr *= (1024 / sizeof(struct file *));  in alloc_fdtable()
136 	data = kvmalloc_array(nr, sizeof(struct file *), GFP_KERNEL_ACCOUNT);  in alloc_fdtable()
163  * Expand the file descriptor table.
208  * This function will expand the file structures, if the requested size exceeds
319 	struct file **old_fds, **new_fds;  in dup_fd()
383 		struct file *f = *old_fds++;  in dup_fd()
400 	memset(new_fds, 0, (new_fdt->max_fds - open_files) * sizeof(struct file *));  in dup_fd()
430 				struct file * file = xchg(&fdt->fd[i], NULL);  in close_files()  local
431 				if (file) {  in close_files()
432 					filp_close(file, files);  in close_files()
522  * allocate a file descriptor, mark it busy.
617  * Install a file pointer in the fd array.
620  * setting the open_fds bitmap and installing the file in the file
622  * installing a file in the array before us.  We need to detect this and
623  * fput() the struct file we are about to overwrite in this case.
637 		struct file *file)  in __fd_install()  argument
648 		rcu_assign_pointer(fdt->fd[fd], file);  in __fd_install()
656 	rcu_assign_pointer(fdt->fd[fd], file);  in __fd_install()
661  * This consumes the "file" refcount, so callers should treat it
662  * as if they had called fput(file).
664 void fd_install(unsigned int fd, struct file *file)  in fd_install()  argument
666 	__fd_install(current->files, fd, file);  in fd_install()
671 static struct file *pick_file(struct files_struct *files, unsigned fd)  in pick_file()
673 	struct file *file = NULL;  in pick_file()  local
681 	file = fdt->fd[fd];  in pick_file()
682 	if (!file)  in pick_file()
689 	return file;  in pick_file()
697 	struct file *file;  in __close_fd()  local
699 	file = pick_file(files, fd);  in __close_fd()
700 	if (!file)  in __close_fd()
703 	return filp_close(file, files);  in __close_fd()
708  * __close_range() - Close all file descriptors in a given range.
710  * @fd:     starting file descriptor to close
711  * @max_fd: last file descriptor to close
713  * This closes a range of file descriptors. All file descriptors
741 		 * we're closing everything so only copy all file descriptors  in __close_range()
742 		 * beneath the lowest file descriptor.  in __close_range()
752 		 * We used to share our file descriptor table, and have now  in __close_range()
761 		struct file *file;  in __close_range()  local
763 		file = pick_file(cur_fds, fd++);  in __close_range()
764 		if (!file)  in __close_range()
767 		filp_close(file, cur_fds);  in __close_range()
774 		 * the new file descriptor table and drop the old one.  in __close_range()
789 int __close_fd_get_file(unsigned int fd, struct file **res)  in __close_fd_get_file()
792 	struct file *file;  in __close_fd_get_file()  local
798 	file = fdt->fd[fd];  in __close_fd_get_file()
799 	if (!file)  in __close_fd_get_file()
803 	get_file(file);  in __close_fd_get_file()
804 	*res = file;  in __close_fd_get_file()
812  * variant of close_fd that gets a ref on the file for later fput.
813  * The caller must ensure that filp_close() called on the file, and then
816 int close_fd_get_file(unsigned int fd, struct file **res)  in close_fd_get_file()
846 			struct file *file;  in do_close_on_exec()  local
849 			file = fdt->fd[fd];  in do_close_on_exec()
850 			if (!file)  in do_close_on_exec()
855 			filp_close(file, files);  in do_close_on_exec()
864 static inline struct file *__fget_files_rcu(struct files_struct *files,  in __fget_files_rcu()
868 		struct file *file;  in __fget_files_rcu()  local
870 		struct file __rcu **fdentry;  in __fget_files_rcu()
876 		file = rcu_dereference_raw(*fdentry);  in __fget_files_rcu()
877 		if (unlikely(!file))  in __fget_files_rcu()
880 		if (unlikely(file->f_mode & mask))  in __fget_files_rcu()
884 		 * Ok, we have a file pointer. However, because we do  in __fget_files_rcu()
886 		 * that file being closed.  in __fget_files_rcu()
890 		 *  (a) the file ref already went down to zero,  in __fget_files_rcu()
894 		if (unlikely(!get_file_rcu_many(file, refs)))  in __fget_files_rcu()
898 		 *  (b) the file table entry has changed under us.  in __fget_files_rcu()
906 		    unlikely(rcu_dereference_raw(*fdentry) != file)) {  in __fget_files_rcu()
907 			fput_many(file, refs);  in __fget_files_rcu()
912 		 * Ok, we have a ref to the file, and checked that it  in __fget_files_rcu()
915 		return file;  in __fget_files_rcu()
919 static struct file *__fget_files(struct files_struct *files, unsigned int fd,  in __fget_files()
922 	struct file *file;  in __fget_files()  local
925 	file = __fget_files_rcu(files, fd, mask, refs);  in __fget_files()
928 	return file;  in __fget_files()
931 static inline struct file *__fget(unsigned int fd, fmode_t mask,  in __fget()
937 struct file *fget_many(unsigned int fd, unsigned int refs)  in fget_many()
942 struct file *fget(unsigned int fd)  in fget()
948 struct file *fget_raw(unsigned int fd)  in fget_raw()
954 struct file *fget_task(struct task_struct *task, unsigned int fd)  in fget_task()
956 	struct file *file = NULL;  in fget_task()  local
960 		file = __fget_files(task->files, fd, 0, 1);  in fget_task()
963 	return file;  in fget_task()
967  * Lightweight file lookup - no refcnt increment if fd table isn't shared.
972  *    to userspace (i.e. you cannot remember the returned struct file * after
974  * 2) You must not call filp_close on the returned struct file * in between
985 	struct file *file;  in __fget_light()  local
988 		file = __fcheck_files(files, fd);  in __fget_light()
989 		if (!file || unlikely(file->f_mode & mask))  in __fget_light()
991 		return (unsigned long)file;  in __fget_light()
993 		file = __fget(fd, mask, 1);  in __fget_light()
994 		if (!file)  in __fget_light()
996 		return FDPUT_FPUT | (unsigned long)file;  in __fget_light()
1013 	struct file *file = (struct file *)(v & ~3);  in __fdget_pos()  local
1015 	if (file && (file->f_mode & FMODE_ATOMIC_POS)) {  in __fdget_pos()
1016 		if (file_count(file) > 1) {  in __fdget_pos()
1018 			mutex_lock(&file->f_pos_lock);  in __fdget_pos()
1024 void __f_unlock_pos(struct file *f)  in __f_unlock_pos()
1030  * We only lock f_pos if we have threads or if the file might be
1032  * file count (done either by fdget() or by fork()).
1061 	struct file *file, unsigned fd, unsigned flags)  in do_dup2()  argument
1064 	struct file *tofree;  in do_dup2()
1071 	 * file immediately after grabbing descriptor, mark it larval if  in do_dup2()
1085 	get_file(file);  in do_dup2()
1086 	rcu_assign_pointer(fdt->fd[fd], file);  in do_dup2()
1104 int replace_fd(unsigned fd, struct file *file, unsigned flags)  in replace_fd()  argument
1109 	if (!file)  in replace_fd()
1119 	return do_dup2(files, file, fd, flags);  in replace_fd()
1127  * __receive_fd() - Install received file into file descriptor table
1130  * @file: struct file that was received from another process
1134  * Installs a received file into the file descriptor table, with appropriate
1139  * struct file.
1143 int __receive_fd(int fd, struct file *file, int __user *ufd, unsigned int o_flags)  in __receive_fd()  argument
1148 	error = security_file_receive(file);  in __receive_fd()
1170 		fd_install(new_fd, get_file(file));  in __receive_fd()
1172 		error = replace_fd(new_fd, file, o_flags);  in __receive_fd()
1178 	__receive_sock(file);  in __receive_fd()
1185 	struct file *file;  in ksys_dup3()  local
1199 	file = fcheck(oldfd);  in ksys_dup3()
1200 	if (unlikely(!file))  in ksys_dup3()
1207 	return do_dup2(files, file, newfd, flags);  in ksys_dup3()
1239 	struct file *file = fget_raw(fildes);  in SYSCALL_DEFINE1()  local
1241 	if (file) {  in SYSCALL_DEFINE1()
1244 			fd_install(ret, file);  in SYSCALL_DEFINE1()
1246 			fput(file);  in SYSCALL_DEFINE1()
1251 int f_dupfd(unsigned int from, struct file *file, unsigned flags)  in f_dupfd()  argument
1258 		get_file(file);  in f_dupfd()
1259 		fd_install(err, file);  in f_dupfd()
1265 		int (*f)(const void *, struct file *, unsigned),  in iterate_fd()  argument
1274 		struct file *file;  in iterate_fd()  local
1275 		file = rcu_dereference_check_fdtable(files, fdt->fd[n]);  in iterate_fd()
1276 		if (!file)  in iterate_fd()
1278 		res = f(p, file, n);  in iterate_fd()