Commit 77b90401 authored by Arnd Bergmann's avatar Arnd Bergmann
Browse files

compat_ioctl: simplify the implementation 



Now that both native and compat ioctl syscalls are
in the same file, a couple of simplifications can
be made, bringing the implementation closer together:

- do_vfs_ioctl(), ioctl_preallocate(), and compat_ioctl_preallocate()
  can become static, allowing the compiler to optimize better

- slightly update the coding style for consistency between
  the functions.

- rather than listing each command in two switch statements
  for the compat case, just call a single function that has
  all the common commands.

As a side-effect, FS_IOC_RESVSP/FS_IOC_RESVSP64 are now available
to x86 compat tasks, along with FS_IOC_RESVSP_32/FS_IOC_RESVSP64_32.
This is harmless for i386 emulation, and can be considered a bugfix
for x32 emulation, which never supported these in the past.

Reviewed-by: default avatarBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 2af563d0

fs/internal.h

+0 −6
Original line number Diff line number Diff line
@@ -180,11 +180,5 @@ extern void mnt_pin_kill(struct mount *m); 
 */

extern const struct dentry_operations ns_dentry_operations;



/*

 * fs/ioctl.c

 */

extern int do_vfs_ioctl(struct file *file, unsigned int fd, unsigned int cmd,

		    unsigned long arg);



/* direct-io.c: */

int sb_init_dio_done_wq(struct super_block *sb);

fs/ioctl.c

+64 −93
Original line number Diff line number Diff line
@@ -467,7 +467,7 @@ EXPORT_SYMBOL(generic_block_fiemap); 
 * Only the l_start, l_len and l_whence fields of the 'struct space_resv'

 * are used here, rest are ignored.

 */

int ioctl_preallocate(struct file *filp, int mode, void __user *argp)

static int ioctl_preallocate(struct file *filp, int mode, void __user *argp)

{

	struct inode *inode = file_inode(filp);

	struct space_resv sr;
@@ -495,7 +495,7 @@ 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 */

int compat_ioctl_preallocate(struct file *file, int mode,

static int compat_ioctl_preallocate(struct file *file, int mode,

				    struct space_resv_32 __user *argp)

{

	struct inode *inode = file_inode(file);
@@ -521,11 +521,9 @@ int compat_ioctl_preallocate(struct file *file, int mode, 
}

#endif



static int file_ioctl(struct file *filp, unsigned int cmd,

		unsigned long arg)

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

{

	struct inode *inode = file_inode(filp);

	int __user *p = (int __user *)arg;



	switch (cmd) {

	case FIBMAP:
@@ -542,7 +540,7 @@ static int file_ioctl(struct file *filp, unsigned int cmd, 
		return ioctl_preallocate(filp, FALLOC_FL_ZERO_RANGE, p);

	}



	return vfs_ioctl(filp, cmd, arg);

	return -ENOIOCTLCMD;

}



static int ioctl_fionbio(struct file *filp, int __user *argp)
@@ -661,53 +659,48 @@ out: 
}



/*

 * When you add any new common ioctls to the switches above and below

 * please update compat_sys_ioctl() too.

 *

 * 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.

 */

int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,

	     unsigned long arg)

static int do_vfs_ioctl(struct file *filp, unsigned int fd,

			unsigned int cmd, unsigned long arg)

{

	int error = 0;

	void __user *argp = (void __user *)arg;

	struct inode *inode = file_inode(filp);



	switch (cmd) {

	case FIOCLEX:

		set_close_on_exec(fd, 1);

		break;

		return 0;



	case FIONCLEX:

		set_close_on_exec(fd, 0);

		break;

		return 0;



	case FIONBIO:

		error = ioctl_fionbio(filp, argp);

		break;

		return ioctl_fionbio(filp, argp);



	case FIOASYNC:

		error = ioctl_fioasync(fd, filp, argp);

		break;

		return ioctl_fioasync(fd, filp, argp);



	case FIOQSIZE:

		if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) ||

		    S_ISLNK(inode->i_mode)) {

			loff_t res = inode_get_bytes(inode);

			error = copy_to_user(argp, &res, sizeof(res)) ?

			return copy_to_user(argp, &res, sizeof(res)) ?

					    -EFAULT : 0;

		} else

			error = -ENOTTY;

		break;

		}



		return -ENOTTY;



	case FIFREEZE:

		error = ioctl_fsfreeze(filp);

		break;

		return ioctl_fsfreeze(filp);



	case FITHAW:

		error = ioctl_fsthaw(filp);

		break;

		return ioctl_fsthaw(filp);



	case FS_IOC_FIEMAP:

		return ioctl_fiemap(filp, argp);
@@ -716,6 +709,7 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, 
		/* anon_bdev filesystems may not have a block size */

		if (!inode->i_sb->s_blocksize)

			return -EINVAL;



		return put_user(inode->i_sb->s_blocksize, (int __user *)argp);



	case FICLONE:
@@ -729,24 +723,30 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, 


	default:

		if (S_ISREG(inode->i_mode))

			error = file_ioctl(filp, cmd, arg);

		else

			error = vfs_ioctl(filp, cmd, arg);

			return file_ioctl(filp, cmd, argp);

		break;

	}

	return error;



	return -ENOIOCTLCMD;

}



int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)

{

	int error;

	struct fd f = fdget(fd);

	int error;



	if (!f.file)

		return -EBADF;



	error = security_file_ioctl(f.file, cmd, arg);

	if (!error)

	if (error)

		goto out;



	error = do_vfs_ioctl(f.file, fd, cmd, arg);

	if (error == -ENOIOCTLCMD)

		error = vfs_ioctl(f.file, cmd, arg);



out:

	fdput(f);

	return error;

}
@@ -790,92 +790,63 @@ long compat_ptr_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
EXPORT_SYMBOL(compat_ptr_ioctl);



COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,

		       compat_ulong_t, arg32)

		       compat_ulong_t, arg)

{

	unsigned long arg = arg32;

	struct fd f = fdget(fd);

	int error = -EBADF;

	int error;



	if (!f.file)

		goto out;

		return -EBADF;



	/* RED-PEN how should LSM module know it's handling 32bit? */

	error = security_file_ioctl(f.file, cmd, arg);

	if (error)

		goto out_fput;

		goto out;



	switch (cmd) {

	/* these are never seen by ->ioctl(), no argument or int argument */

	case FIOCLEX:

	case FIONCLEX:

	case FIFREEZE:

	case FITHAW:

	/* FICLONE takes an int argument, so don't use compat_ptr() */

	case FICLONE:

		goto do_ioctl;

	/* these are never seen by ->ioctl(), pointer argument */

	case FIONBIO:

	case FIOASYNC:

	case FIOQSIZE:

	case FS_IOC_FIEMAP:

	case FIGETBSZ:

	case FICLONERANGE:

	case FIDEDUPERANGE:

		goto found_handler;

	/*

	 * The next group is the stuff handled inside file_ioctl().

	 * For regular files these never reach ->ioctl(); for

	 * devices, sockets, etc. they do and one (FIONREAD) is

	 * even accepted in some cases.  In all those cases

	 * argument has the same type, so we can handle these

	 * here, shunting them towards do_vfs_ioctl().

	 * ->compat_ioctl() will never see any of those.

	 */

	/* pointer argument, never actually handled by ->ioctl() */

	case FIBMAP:

		goto found_handler;

	/* handled by some ->ioctl(); always a pointer to int */

	case FIONREAD:

		goto found_handler;

	/* these get messy on amd64 due to alignment differences */

		error = ioctl_file_clone(f.file, arg, 0, 0, 0);

		break;



#if defined(CONFIG_X86_64)

	/* these get messy on amd64 due to alignment differences */

	case FS_IOC_RESVSP_32:

	case FS_IOC_RESVSP64_32:

		error = compat_ioctl_preallocate(f.file, 0, compat_ptr(arg));

		goto out_fput;

		break;

	case FS_IOC_UNRESVSP_32:

	case FS_IOC_UNRESVSP64_32:

		error = compat_ioctl_preallocate(f.file, FALLOC_FL_PUNCH_HOLE,

				compat_ptr(arg));

		goto out_fput;

		break;

	case FS_IOC_ZERO_RANGE_32:

		error = compat_ioctl_preallocate(f.file, FALLOC_FL_ZERO_RANGE,

				compat_ptr(arg));

		goto out_fput;

#else

	case FS_IOC_RESVSP:

	case FS_IOC_RESVSP64:

	case FS_IOC_UNRESVSP:

	case FS_IOC_UNRESVSP64:

	case FS_IOC_ZERO_RANGE:

		goto found_handler;

		break;

#endif



	/*

	 * everything else in do_vfs_ioctl() takes either a compatible

	 * pointer argument or no argument -- call it with a modified

	 * argument.

	 */

	default:

		if (f.file->f_op->compat_ioctl) {

			error = f.file->f_op->compat_ioctl(f.file, cmd, arg);

		error = do_vfs_ioctl(f.file, fd, cmd,

				     (unsigned long)compat_ptr(arg));

		if (error != -ENOIOCTLCMD)

				goto out_fput;

		}

			break;



		if (f.file->f_op->compat_ioctl)

			error = f.file->f_op->compat_ioctl(f.file, cmd, arg);

		if (error == -ENOIOCTLCMD)

			error = -ENOTTY;

		goto out_fput;

		break;

	}



 found_handler:

	arg = (unsigned long)compat_ptr(arg);

 do_ioctl:

	error = do_vfs_ioctl(f.file, fd, cmd, arg);

 out_fput:

	fdput(f);

 out:

	fdput(f);



	return error;

}

#endif

include/linux/falloc.h

+0 −2
Original line number Diff line number Diff line
@@ -51,8 +51,6 @@ struct space_resv_32 { 
#define FS_IOC_UNRESVSP64_32	_IOW ('X', 43, struct space_resv_32)

#define FS_IOC_ZERO_RANGE_32	_IOW ('X', 57, struct space_resv_32)



int compat_ioctl_preallocate(struct file *, int, struct space_resv_32 __user *);



#endif



#endif /* _FALLOC_H_ */

include/linux/fs.h

+0 −4
Original line number Diff line number Diff line
@@ -2552,10 +2552,6 @@ extern int finish_open(struct file *file, struct dentry *dentry, 
			int (*open)(struct inode *, struct file *));

extern int finish_no_open(struct file *file, struct dentry *dentry);



/* fs/ioctl.c */



extern int ioctl_preallocate(struct file *filp, int mode, void __user *argp);



/* fs/dcache.c */

extern void __init vfs_caches_init_early(void);

extern void __init vfs_caches_init(void);

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