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()
102 	nr /= (1024 / sizeof(struct file *));  in alloc_fdtable()
104 	nr *= (1024 / sizeof(struct file *));  in alloc_fdtable()
120 	data = kvmalloc_array(nr, sizeof(struct file *), GFP_KERNEL_ACCOUNT);  in alloc_fdtable()
147  * Expand the file descriptor table.
192  * This function will expand the file structures, if the requested size exceeds
290 	struct file **old_fds, **new_fds;  in dup_fd()
354 		struct file *f = *old_fds++;  in dup_fd()
371 	memset(new_fds, 0, (new_fdt->max_fds - open_files) * sizeof(struct file *));  in dup_fd()
401 				struct file * file = xchg(&fdt->fd[i], NULL);  in close_files()  local
402 				if (file) {  in close_files()
403 					filp_close(file, files);  in close_files()
468  * allocate a file descriptor, mark it busy.
558  * Install a file pointer in the fd array.
561  * setting the open_fds bitmap and installing the file in the file
563  * installing a file in the array before us.  We need to detect this and
564  * fput() the struct file we are about to overwrite in this case.
569  * This consumes the "file" refcount, so callers should treat it
570  * as if they had called fput(file).
573 void fd_install(unsigned int fd, struct file *file)  in fd_install()  argument
585 		rcu_assign_pointer(fdt->fd[fd], file);  in fd_install()
593 	rcu_assign_pointer(fdt->fd[fd], file);  in fd_install()
600  * pick_file - return file associatd with fd
601  * @files: file struct to retrieve file from
602  * @fd: file descriptor to retrieve file for
605  * current maximum number of file descriptors for that fdtable.
607  * Returns: The file associated with @fd, on error returns an error pointer.
609 static struct file *pick_file(struct files_struct *files, unsigned fd)  in pick_file()
611 	struct file *file;  in pick_file()  local
617 		file = ERR_PTR(-EINVAL);  in pick_file()
620 	file = fdt->fd[fd];  in pick_file()
621 	if (!file) {  in pick_file()
622 		file = ERR_PTR(-EBADF);  in pick_file()
630 	return file;  in pick_file()
636 	struct file *file;  in close_fd()  local
638 	file = pick_file(files, fd);  in close_fd()
639 	if (IS_ERR(file))  in close_fd()
642 	return filp_close(file, files);  in close_fd()
677 		struct file *file;  in __range_close()  local
679 		file = pick_file(cur_fds, fd++);  in __range_close()
680 		if (!IS_ERR(file)) {  in __range_close()
681 			/* found a valid file to close */  in __range_close()
682 			filp_close(file, cur_fds);  in __range_close()
688 		if (PTR_ERR(file) == -EINVAL)  in __range_close()
694  * __close_range() - Close all file descriptors in a given range.
696  * @fd:     starting file descriptor to close
697  * @max_fd: last file descriptor to close
699  * This closes a range of file descriptors. All file descriptors
719 		 * copy all of the file descriptors since they still want to  in __close_range()
726 			 * file descriptors beneath the lowest file descriptor.  in __close_range()
739 		 * We used to share our file descriptor table, and have now  in __close_range()
754 		 * the new file descriptor table and drop the old one.  in __close_range()
769 int __close_fd_get_file(unsigned int fd, struct file **res)  in __close_fd_get_file()
772 	struct file *file;  in __close_fd_get_file()  local
778 	file = fdt->fd[fd];  in __close_fd_get_file()
779 	if (!file)  in __close_fd_get_file()
783 	get_file(file);  in __close_fd_get_file()
784 	*res = file;  in __close_fd_get_file()
792  * variant of close_fd that gets a ref on the file for later fput.
793  * The caller must ensure that filp_close() called on the file, and then
796 int close_fd_get_file(unsigned int fd, struct file **res)  in close_fd_get_file()
826 			struct file *file;  in do_close_on_exec()  local
829 			file = fdt->fd[fd];  in do_close_on_exec()
830 			if (!file)  in do_close_on_exec()
835 			filp_close(file, files);  in do_close_on_exec()
844 static struct file *__fget_files(struct files_struct *files, unsigned int fd,  in __fget_files()
847 	struct file *file;  in __fget_files()  local
851 	file = files_lookup_fd_rcu(files, fd);  in __fget_files()
852 	if (file) {  in __fget_files()
853 		/* File object ref couldn't be taken.  in __fget_files()
855 		 * we loop to catch the new file (or NULL pointer)  in __fget_files()
857 		if (file->f_mode & mask)  in __fget_files()
858 			file = NULL;  in __fget_files()
859 		else if (!get_file_rcu_many(file, refs))  in __fget_files()
864 	return file;  in __fget_files()
867 static inline struct file *__fget(unsigned int fd, fmode_t mask,  in __fget()
873 struct file *fget_many(unsigned int fd, unsigned int refs)  in fget_many()
878 struct file *fget(unsigned int fd)  in fget()
884 struct file *fget_raw(unsigned int fd)  in fget_raw()
890 struct file *fget_task(struct task_struct *task, unsigned int fd)  in fget_task()
892 	struct file *file = NULL;  in fget_task()  local
896 		file = __fget_files(task->files, fd, 0, 1);  in fget_task()
899 	return file;  in fget_task()
902 struct file *task_lookup_fd_rcu(struct task_struct *task, unsigned int fd)  in task_lookup_fd_rcu()
906 	struct file *file = NULL;  in task_lookup_fd_rcu()  local
911 		file = files_lookup_fd_rcu(files, fd);  in task_lookup_fd_rcu()
914 	return file;  in task_lookup_fd_rcu()
917 struct file *task_lookup_next_fd_rcu(struct task_struct *task, unsigned int *ret_fd)  in task_lookup_next_fd_rcu()
922 	struct file *file = NULL;  in task_lookup_next_fd_rcu()  local
928 			file = files_lookup_fd_rcu(files, fd);  in task_lookup_next_fd_rcu()
929 			if (file)  in task_lookup_next_fd_rcu()
935 	return file;  in task_lookup_next_fd_rcu()
939  * Lightweight file lookup - no refcnt increment if fd table isn't shared.
944  *    to userspace (i.e. you cannot remember the returned struct file * after
946  * 2) You must not call filp_close on the returned struct file * in between
957 	struct file *file;  in __fget_light()  local
960 		file = files_lookup_fd_raw(files, fd);  in __fget_light()
961 		if (!file || unlikely(file->f_mode & mask))  in __fget_light()
963 		return (unsigned long)file;  in __fget_light()
965 		file = __fget(fd, mask, 1);  in __fget_light()
966 		if (!file)  in __fget_light()
968 		return FDPUT_FPUT | (unsigned long)file;  in __fget_light()
985 	struct file *file = (struct file *)(v & ~3);  in __fdget_pos()  local
987 	if (file && (file->f_mode & FMODE_ATOMIC_POS)) {  in __fdget_pos()
988 		if (file_count(file) > 1) {  in __fdget_pos()
990 			mutex_lock(&file->f_pos_lock);  in __fdget_pos()
996 void __f_unlock_pos(struct file *f)  in __f_unlock_pos()
1002  * We only lock f_pos if we have threads or if the file might be
1004  * file count (done either by fdget() or by fork()).
1033 	struct file *file, unsigned fd, unsigned flags)  in do_dup2()  argument
1036 	struct file *tofree;  in do_dup2()
1043 	 * file immediately after grabbing descriptor, mark it larval if  in do_dup2()
1057 	get_file(file);  in do_dup2()
1058 	rcu_assign_pointer(fdt->fd[fd], file);  in do_dup2()
1076 int replace_fd(unsigned fd, struct file *file, unsigned flags)  in replace_fd()  argument
1081 	if (!file)  in replace_fd()
1091 	return do_dup2(files, file, fd, flags);  in replace_fd()
1099  * __receive_fd() - Install received file into file descriptor table
1100  * @file: struct file that was received from another process
1104  * Installs a received file into the file descriptor table, with appropriate
1109  * struct file.
1113 int __receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)  in __receive_fd()  argument
1118 	error = security_file_receive(file);  in __receive_fd()
1134 	fd_install(new_fd, get_file(file));  in __receive_fd()
1135 	__receive_sock(file);  in __receive_fd()
1139 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)  in receive_fd_replace()  argument
1143 	error = security_file_receive(file);  in receive_fd_replace()
1146 	error = replace_fd(new_fd, file, o_flags);  in receive_fd_replace()
1149 	__receive_sock(file);  in receive_fd_replace()
1153 int receive_fd(struct file *file, unsigned int o_flags)  in receive_fd()  argument
1155 	return __receive_fd(file, NULL, o_flags);  in receive_fd()
1162 	struct file *file;  in ksys_dup3()  local
1176 	file = files_lookup_fd_locked(files, oldfd);  in ksys_dup3()
1177 	if (unlikely(!file))  in ksys_dup3()
1184 	return do_dup2(files, file, newfd, flags);  in ksys_dup3()
1216 	struct file *file = fget_raw(fildes);  in SYSCALL_DEFINE1()  local
1218 	if (file) {  in SYSCALL_DEFINE1()
1221 			fd_install(ret, file);  in SYSCALL_DEFINE1()
1223 			fput(file);  in SYSCALL_DEFINE1()
1228 int f_dupfd(unsigned int from, struct file *file, unsigned flags)  in f_dupfd()  argument
1236 		get_file(file);  in f_dupfd()
1237 		fd_install(err, file);  in f_dupfd()
1243 		int (*f)(const void *, struct file *, unsigned),  in iterate_fd()  argument
1252 		struct file *file;  in iterate_fd()  local
1253 		file = rcu_dereference_check_fdtable(files, fdt->fd[n]);  in iterate_fd()
1254 		if (!file)  in iterate_fd()
1256 		res = f(p, file, n);  in iterate_fd()