linux/fs/ioctl.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ioctl.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/capability.h>
#include <linux/compat.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/uaccess.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <linux/falloc.h>
#include <linux/sched/signal.h>
#include <linux/fiemap.h>
#include <linux/mount.h>
#include <linux/fscrypt.h>
#include <linux/fileattr.h>

#include "internal.h"

#include <asm/ioctls.h>

/* So that the fiemap access checks can't overflow on 32 bit machines. */
#define FIEMAP_MAX_EXTENTS …

/**
 * vfs_ioctl - call filesystem specific ioctl methods
 * @filp:	open file to invoke ioctl method on
 * @cmd:	ioctl command to execute
 * @arg:	command-specific argument for ioctl
 *
 * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
 * returns -ENOTTY.
 *
 * Returns 0 on success, -errno on error.
 */
long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{ … }
EXPORT_SYMBOL(…);

static int ioctl_fibmap(struct file *filp, int __user *p)
{ … }

/**
 * fiemap_fill_next_extent - Fiemap helper function
 * @fieinfo:	Fiemap context passed into ->fiemap
 * @logical:	Extent logical start offset, in bytes
 * @phys:	Extent physical start offset, in bytes
 * @len:	Extent length, in bytes
 * @flags:	FIEMAP_EXTENT flags that describe this extent
 *
 * Called from file system ->fiemap callback. Will populate extent
 * info as passed in via arguments and copy to user memory. On
 * success, extent count on fieinfo is incremented.
 *
 * Returns 0 on success, -errno on error, 1 if this was the last
 * extent that will fit in user array.
 */
int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
			    u64 phys, u64 len, u32 flags)
{ … }
EXPORT_SYMBOL(…);

/**
 * fiemap_prep - check validity of requested flags for fiemap
 * @inode:	Inode to operate on
 * @fieinfo:	Fiemap context passed into ->fiemap
 * @start:	Start of the mapped range
 * @len:	Length of the mapped range, can be truncated by this function.
 * @supported_flags:	Set of fiemap flags that the file system understands
 *
 * This function must be called from each ->fiemap instance to validate the
 * fiemap request against the file system parameters.
 *
 * Returns 0 on success, or a negative error on failure.
 */
int fiemap_prep(struct inode *inode, struct fiemap_extent_info *fieinfo,
		u64 start, u64 *len, u32 supported_flags)
{ … }
EXPORT_SYMBOL(…);

static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap)
{ … }

static long ioctl_file_clone(struct file *dst_file, unsigned long srcfd,
			     u64 off, u64 olen, u64 destoff)
{ … }

static long ioctl_file_clone_range(struct file *file,
				   struct file_clone_range __user *argp)
{ … }

/*
 * This provides compatibility with legacy XFS pre-allocation ioctls
 * which predate the fallocate syscall.
 *
 * Only the l_start, l_len and l_whence fields of the 'struct space_resv'
 * are used here, rest are ignored.
 */
static int ioctl_preallocate(struct file *filp, int mode, void __user *argp)
{ … }

/* on ia32 l_start is on a 32-bit boundary */
#if defined CONFIG_COMPAT && defined(CONFIG_X86_64)
/* just account for different alignment */
static int compat_ioctl_preallocate(struct file *file, int mode,
				    struct space_resv_32 __user *argp)
{ … }
#endif

static int file_ioctl(struct file *filp, unsigned int cmd, int __user *p)
{ … }

static int ioctl_fionbio(struct file *filp, int __user *argp)
{ … }

static int ioctl_fioasync(unsigned int fd, struct file *filp,
			  int __user *argp)
{ … }

static int ioctl_fsfreeze(struct file *filp)
{ … }

static int ioctl_fsthaw(struct file *filp)
{ … }

static int ioctl_file_dedupe_range(struct file *file,
				   struct file_dedupe_range __user *argp)
{ … }

/**
 * fileattr_fill_xflags - initialize fileattr with xflags
 * @fa:		fileattr pointer
 * @xflags:	FS_XFLAG_* flags
 *
 * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags).  All
 * other fields are zeroed.
 */
void fileattr_fill_xflags(struct fileattr *fa, u32 xflags)
{ … }
EXPORT_SYMBOL(…);

/**
 * fileattr_fill_flags - initialize fileattr with flags
 * @fa:		fileattr pointer
 * @flags:	FS_*_FL flags
 *
 * Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
 * All other fields are zeroed.
 */
void fileattr_fill_flags(struct fileattr *fa, u32 flags)
{ … }
EXPORT_SYMBOL(…);

/**
 * vfs_fileattr_get - retrieve miscellaneous file attributes
 * @dentry:	the object to retrieve from
 * @fa:		fileattr pointer
 *
 * Call i_op->fileattr_get() callback, if exists.
 *
 * Return: 0 on success, or a negative error on failure.
 */
int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
{ … }
EXPORT_SYMBOL(…);

/**
 * copy_fsxattr_to_user - copy fsxattr to userspace.
 * @fa:		fileattr pointer
 * @ufa:	fsxattr user pointer
 *
 * Return: 0 on success, or -EFAULT on failure.
 */
int copy_fsxattr_to_user(const struct fileattr *fa, struct fsxattr __user *ufa)
{ … }
EXPORT_SYMBOL(…);

static int copy_fsxattr_from_user(struct fileattr *fa,
				  struct fsxattr __user *ufa)
{ … }

/*
 * Generic function to check FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS values and reject
 * any invalid configurations.
 *
 * Note: must be called with inode lock held.
 */
static int fileattr_set_prepare(struct inode *inode,
			      const struct fileattr *old_ma,
			      struct fileattr *fa)
{ … }

/**
 * vfs_fileattr_set - change miscellaneous file attributes
 * @idmap:	idmap of the mount
 * @dentry:	the object to change
 * @fa:		fileattr pointer
 *
 * After verifying permissions, call i_op->fileattr_set() callback, if
 * exists.
 *
 * Verifying attributes involves retrieving current attributes with
 * i_op->fileattr_get(), this also allows initializing attributes that have
 * not been set by the caller to current values.  Inode lock is held
 * thoughout to prevent racing with another instance.
 *
 * Return: 0 on success, or a negative error on failure.
 */
int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
		     struct fileattr *fa)
{ … }
EXPORT_SYMBOL(…);

static int ioctl_getflags(struct file *file, unsigned int __user *argp)
{ … }

static int ioctl_setflags(struct file *file, unsigned int __user *argp)
{ … }

static int ioctl_fsgetxattr(struct file *file, void __user *argp)
{ … }

static int ioctl_fssetxattr(struct file *file, void __user *argp)
{ … }

static int ioctl_getfsuuid(struct file *file, void __user *argp)
{ … }

static int ioctl_get_fs_sysfs_path(struct file *file, void __user *argp)
{ … }

/*
 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
 * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
 *
 * When you add any new common ioctls to the switches above and below,
 * please ensure they have compatible arguments in compat mode.
 *
 * The LSM mailing list should also be notified of any command additions or
 * changes, as specific LSMs may be affected.
 */
static int do_vfs_ioctl(struct file *filp, unsigned int fd,
			unsigned int cmd, unsigned long arg)
{ … }

SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
{ … }

#ifdef CONFIG_COMPAT
/**
 * compat_ptr_ioctl - generic implementation of .compat_ioctl file operation
 * @file: The file to operate on.
 * @cmd: The ioctl command number.
 * @arg: The argument to the ioctl.
 *
 * This is not normally called as a function, but instead set in struct
 * file_operations as
 *
 *     .compat_ioctl = compat_ptr_ioctl,
 *
 * On most architectures, the compat_ptr_ioctl() just passes all arguments
 * to the corresponding ->ioctl handler. The exception is arch/s390, where
 * compat_ptr() clears the top bit of a 32-bit pointer value, so user space
 * pointers to the second 2GB alias the first 2GB, as is the case for
 * native 32-bit s390 user space.
 *
 * The compat_ptr_ioctl() function must therefore be used only with ioctl
 * functions that either ignore the argument or pass a pointer to a
 * compatible data type.
 *
 * If any ioctl command handled by fops->unlocked_ioctl passes a plain
 * integer instead of a pointer, or any of the passed data types
 * is incompatible between 32-bit and 64-bit architectures, a proper
 * handler is required instead of compat_ptr_ioctl.
 */
long compat_ptr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{ … }
EXPORT_SYMBOL(…);

COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
		       compat_ulong_t, arg)
{ … }
#endif