3  *  linux/fs/file.c
17 #include <linux/file.h>
49  * space if any.  This does not copy the file pointers.  Called with the files
71  * Copy all file descriptors from the old table to the new, expanded table and
80 	cpy = ofdt->max_fds * sizeof(struct file *);  in copy_fdtable()
81 	set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);  in copy_fdtable()
100 	nr /= (1024 / sizeof(struct file *));  in alloc_fdtable()
102 	nr *= (1024 / sizeof(struct file *));  in alloc_fdtable()
118 	data = kvmalloc_array(nr, sizeof(struct file *), GFP_KERNEL_ACCOUNT);  in alloc_fdtable()
145  * Expand the file descriptor table.
190  * This function will expand the file structures, if the requested size exceeds
288 	struct file **old_fds, **new_fds;  in dup_fd()
352 		struct file *f = *old_fds++;  in dup_fd()
369 	memset(new_fds, 0, (new_fdt->max_fds - open_files) * sizeof(struct file *));  in dup_fd()
399 				struct file * file = xchg(&fdt->fd[i], NULL);  in close_files()  local
400 				if (file) {  in close_files()
401 					filp_close(file, files);  in close_files()
491  * allocate a file descriptor, mark it busy.
586  * Install a file pointer in the fd array.
589  * setting the open_fds bitmap and installing the file in the file
591  * installing a file in the array before us.  We need to detect this and
592  * fput() the struct file we are about to overwrite in this case.
606 		struct file *file)  in __fd_install()  argument
617 		rcu_assign_pointer(fdt->fd[fd], file);  in __fd_install()
625 	rcu_assign_pointer(fdt->fd[fd], file);  in __fd_install()
630  * This consumes the "file" refcount, so callers should treat it
631  * as if they had called fput(file).
633 void fd_install(unsigned int fd, struct file *file)  in fd_install()  argument
635 	__fd_install(current->files, fd, file);  in fd_install()
640 static struct file *pick_file(struct files_struct *files, unsigned fd)  in pick_file()
642 	struct file *file = NULL;  in pick_file()  local
649 	file = fdt->fd[fd];  in pick_file()
650 	if (!file)  in pick_file()
657 	return file;  in pick_file()
665 	struct file *file;  in __close_fd()  local
667 	file = pick_file(files, fd);  in __close_fd()
668 	if (!file)  in __close_fd()
671 	return filp_close(file, files);  in __close_fd()
676  * __close_range() - Close all file descriptors in a given range.
678  * @fd:     starting file descriptor to close
679  * @max_fd: last file descriptor to close
681  * This closes a range of file descriptors. All file descriptors
709 		 * we're closing everything so only copy all file descriptors  in __close_range()
710 		 * beneath the lowest file descriptor.  in __close_range()
720 		 * We used to share our file descriptor table, and have now  in __close_range()
729 		struct file *file;  in __close_range()  local
731 		file = pick_file(cur_fds, fd++);  in __close_range()
732 		if (!file)  in __close_range()
735 		filp_close(file, cur_fds);  in __close_range()
742 		 * the new file descriptor table and drop the old one.  in __close_range()
754  * variant of __close_fd that gets a ref on the file for later fput.
755  * The caller must ensure that filp_close() called on the file, and then
758 int __close_fd_get_file(unsigned int fd, struct file **res)  in __close_fd_get_file()
761 	struct file *file;  in __close_fd_get_file()  local
768 	file = fdt->fd[fd];  in __close_fd_get_file()
769 	if (!file)  in __close_fd_get_file()
774 	get_file(file);  in __close_fd_get_file()
775 	*res = file;  in __close_fd_get_file()
802 			struct file *file;  in do_close_on_exec()  local
805 			file = fdt->fd[fd];  in do_close_on_exec()
806 			if (!file)  in do_close_on_exec()
811 			filp_close(file, files);  in do_close_on_exec()
820 static struct file *__fget_files(struct files_struct *files, unsigned int fd,  in __fget_files()
823 	struct file *file;  in __fget_files()  local
827 	file = fcheck_files(files, fd);  in __fget_files()
828 	if (file) {  in __fget_files()
829 		/* File object ref couldn't be taken.  in __fget_files()
831 		 * we loop to catch the new file (or NULL pointer)  in __fget_files()
833 		if (file->f_mode & mask)  in __fget_files()
834 			file = NULL;  in __fget_files()
835 		else if (!get_file_rcu_many(file, refs))  in __fget_files()
837 		else if (__fcheck_files(files, fd) != file) {  in __fget_files()
838 			fput_many(file, refs);  in __fget_files()
844 	return file;  in __fget_files()
847 static inline struct file *__fget(unsigned int fd, fmode_t mask,  in __fget()
853 struct file *fget_many(unsigned int fd, unsigned int refs)  in fget_many()
858 struct file *fget(unsigned int fd)  in fget()
864 struct file *fget_raw(unsigned int fd)  in fget_raw()
870 struct file *fget_task(struct task_struct *task, unsigned int fd)  in fget_task()
872 	struct file *file = NULL;  in fget_task()  local
876 		file = __fget_files(task->files, fd, 0, 1);  in fget_task()
879 	return file;  in fget_task()
883  * Lightweight file lookup - no refcnt increment if fd table isn't shared.
888  *    to userspace (i.e. you cannot remember the returned struct file * after
890  * 2) You must not call filp_close on the returned struct file * in between
901 	struct file *file;  in __fget_light()  local
904 		file = __fcheck_files(files, fd);  in __fget_light()
905 		if (!file || unlikely(file->f_mode & mask))  in __fget_light()
907 		return (unsigned long)file;  in __fget_light()
909 		file = __fget(fd, mask, 1);  in __fget_light()
910 		if (!file)  in __fget_light()
912 		return FDPUT_FPUT | (unsigned long)file;  in __fget_light()
929 	struct file *file = (struct file *)(v & ~3);  in __fdget_pos()  local
931 	if (file && (file->f_mode & FMODE_ATOMIC_POS)) {  in __fdget_pos()
932 		if (file_count(file) > 1) {  in __fdget_pos()
934 			mutex_lock(&file->f_pos_lock);  in __fdget_pos()
940 void __f_unlock_pos(struct file *f)  in __f_unlock_pos()
946  * We only lock f_pos if we have threads or if the file might be
948  * file count (done either by fdget() or by fork()).
977 	struct file *file, unsigned fd, unsigned flags)  in do_dup2()  argument
980 	struct file *tofree;  in do_dup2()
987 	 * file immediately after grabbing descriptor, mark it larval if  in do_dup2()
1001 	get_file(file);  in do_dup2()
1002 	rcu_assign_pointer(fdt->fd[fd], file);  in do_dup2()
1020 int replace_fd(unsigned fd, struct file *file, unsigned flags)  in replace_fd()  argument
1025 	if (!file)  in replace_fd()
1035 	return do_dup2(files, file, fd, flags);  in replace_fd()
1043  * __receive_fd() - Install received file into file descriptor table
1046  * @file: struct file that was received from another process
1050  * Installs a received file into the file descriptor table, with appropriate
1055  * struct file.
1059 int __receive_fd(int fd, struct file *file, int __user *ufd, unsigned int o_flags)  in __receive_fd()  argument
1064 	error = security_file_receive(file);  in __receive_fd()
1086 		fd_install(new_fd, get_file(file));  in __receive_fd()
1088 		error = replace_fd(new_fd, file, o_flags);  in __receive_fd()
1094 	__receive_sock(file);  in __receive_fd()
1101 	struct file *file;  in ksys_dup3()  local
1115 	file = fcheck(oldfd);  in ksys_dup3()
1116 	if (unlikely(!file))  in ksys_dup3()
1123 	return do_dup2(files, file, newfd, flags);  in ksys_dup3()
1155 	struct file *file = fget_raw(fildes);  in SYSCALL_DEFINE1()  local
1157 	if (file) {  in SYSCALL_DEFINE1()
1160 			fd_install(ret, file);  in SYSCALL_DEFINE1()
1162 			fput(file);  in SYSCALL_DEFINE1()
1167 int f_dupfd(unsigned int from, struct file *file, unsigned flags)  in f_dupfd()  argument
1174 		get_file(file);  in f_dupfd()
1175 		fd_install(err, file);  in f_dupfd()
1181 		int (*f)(const void *, struct file *, unsigned),  in iterate_fd()  argument
1190 		struct file *file;  in iterate_fd()  local
1191 		file = rcu_dereference_check_fdtable(files, fdt->fd[n]);  in iterate_fd()
1192 		if (!file)  in iterate_fd()
1194 		res = f(p, file, n);  in iterate_fd()