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/*
* linux/fs/open.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/utime.h>
#include <linux/file.h>
#include <linux/smp_lock.h>
#include <linux/quotaops.h>
#include <linux/dnotify.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/iobuf.h>
#include <asm/uaccess.h>
#define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
int vfs_statfs(struct super_block *sb, struct statfs *buf)
{
int retval = -ENODEV;
if (sb) {
retval = -ENOSYS;
if (sb->s_op && sb->s_op->statfs) {
memset(buf, 0, sizeof(struct statfs));
lock_kernel();
retval = sb->s_op->statfs(sb, buf);
unlock_kernel();
}
}
return retval;
}
asmlinkage long sys_statfs(const char * path, struct statfs * buf)
{
struct nameidata nd;
int error;
error = user_path_walk(path, &nd);
if (!error) {
struct statfs tmp;
error = vfs_statfs(nd.dentry->d_inode->i_sb, &tmp);
if (!error && copy_to_user(buf, &tmp, sizeof(struct statfs)))
error = -EFAULT;
path_release(&nd);
}
return error;
}
asmlinkage long sys_fstatfs(unsigned int fd, struct statfs * buf)
{
struct file * file;
struct statfs tmp;
int error;
error = -EBADF;
file = fget(fd);
if (!file)
goto out;
error = vfs_statfs(file->f_dentry->d_inode->i_sb, &tmp);
if (!error && copy_to_user(buf, &tmp, sizeof(struct statfs)))
error = -EFAULT;
fput(file);
out:
return error;
}
int do_truncate(struct dentry *dentry, loff_t length)
{
struct inode *inode = dentry->d_inode;
int error;
struct iattr newattrs;
/* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
if (length < 0)
return -EINVAL;
down(&inode->i_sem);
newattrs.ia_size = length;
newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
error = notify_change(dentry, &newattrs);
up(&inode->i_sem);
return error;
}
static inline long do_sys_truncate(const char * path, loff_t length)
{
struct nameidata nd;
struct inode * inode;
int error;
error = -EINVAL;
if (length < 0) /* sorry, but loff_t says... */
goto out;
error = user_path_walk(path, &nd);
if (error)
goto out;
inode = nd.dentry->d_inode;
/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
error = -EISDIR;
if (S_ISDIR(inode->i_mode))
goto dput_and_out;
error = -EINVAL;
if (!S_ISREG(inode->i_mode))
goto dput_and_out;
error = permission(inode,MAY_WRITE);
if (error)
goto dput_and_out;
error = -EROFS;
if (IS_RDONLY(inode))
goto dput_and_out;
error = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
goto dput_and_out;
/*
* Make sure that there are no leases.
*/
error = get_lease(inode, FMODE_WRITE);
if (error)
goto dput_and_out;
error = get_write_access(inode);
if (error)
goto dput_and_out;
error = locks_verify_truncate(inode, NULL, length);
if (!error) {
DQUOT_INIT(inode);
error = do_truncate(nd.dentry, length);
}
put_write_access(inode);
dput_and_out:
path_release(&nd);
out:
return error;
}
asmlinkage long sys_truncate(const char * path, unsigned long length)
{
/* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
return do_sys_truncate(path, (long)length);
}
static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
{
struct inode * inode;
struct dentry *dentry;
struct file * file;
int error;
error = -EINVAL;
if (length < 0)
goto out;
error = -EBADF;
file = fget(fd);
if (!file)
goto out;
/* explicitly opened as large or we are on 64-bit box */
if (file->f_flags & O_LARGEFILE)
small = 0;
dentry = file->f_dentry;
inode = dentry->d_inode;
error = -EINVAL;
if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
goto out_putf;
error = -EINVAL;
/* Cannot ftruncate over 2^31 bytes without large file support */
if (small && length > MAX_NON_LFS)
goto out_putf;
error = -EPERM;
if (IS_APPEND(inode))
goto out_putf;
error = locks_verify_truncate(inode, file, length);
if (!error)
error = do_truncate(dentry, length);
out_putf:
fput(file);
out:
return error;
}
asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
{
return do_sys_ftruncate(fd, length, 1);
}
/* LFS versions of truncate are only needed on 32 bit machines */
#if BITS_PER_LONG == 32
asmlinkage long sys_truncate64(const char * path, loff_t length)
{
return do_sys_truncate(path, length);
}
asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
{
return do_sys_ftruncate(fd, length, 0);
}
#endif
#if !(defined(__alpha__) || defined(__ia64__))
/*
* sys_utime() can be implemented in user-level using sys_utimes().
* Is this for backwards compatibility? If so, why not move it
* into the appropriate arch directory (for those architectures that
* need it).
*/
/* If times==NULL, set access and modification to current time,
* must be owner or have write permission.
* Else, update from *times, must be owner or super user.
*/
asmlinkage long sys_utime(char * filename, struct utimbuf * times)
{
int error;
struct nameidata nd;
struct inode * inode;
struct iattr newattrs;
error = user_path_walk(filename, &nd);
if (error)
goto out;
inode = nd.dentry->d_inode;
error = -EROFS;
if (IS_RDONLY(inode))
goto dput_and_out;
/* Don't worry, the checks are done in inode_change_ok() */
newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
if (times) {
error = get_user(newattrs.ia_atime, ×->actime);
if (!error)
error = get_user(newattrs.ia_mtime, ×->modtime);
if (error)
goto dput_and_out;
newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
} else {
if (current->fsuid != inode->i_uid &&
(error = permission(inode,MAY_WRITE)) != 0)
goto dput_and_out;
}
error = notify_change(nd.dentry, &newattrs);
dput_and_out:
path_release(&nd);
out:
return error;
}
#endif
/* If times==NULL, set access and modification to current time,
* must be owner or have write permission.
* Else, update from *times, must be owner or super user.
*/
asmlinkage long sys_utimes(char * filename, struct timeval * utimes)
{
int error;
struct nameidata nd;
struct inode * inode;
struct iattr newattrs;
error = user_path_walk(filename, &nd);
if (error)
goto out;
inode = nd.dentry->d_inode;
error = -EROFS;
if (IS_RDONLY(inode))
goto dput_and_out;
/* Don't worry, the checks are done in inode_change_ok() */
newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
if (utimes) {
struct timeval times[2];
error = -EFAULT;
if (copy_from_user(×, utimes, sizeof(times)))
goto dput_and_out;
newattrs.ia_atime = times[0].tv_sec;
newattrs.ia_mtime = times[1].tv_sec;
newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
} else {
if ((error = permission(inode,MAY_WRITE)) != 0)
goto dput_and_out;
}
error = notify_change(nd.dentry, &newattrs);
dput_and_out:
path_release(&nd);
out:
return error;
}
/*
* access() needs to use the real uid/gid, not the effective uid/gid.
* We do this by temporarily clearing all FS-related capabilities and
* switching the fsuid/fsgid around to the real ones.
*/
asmlinkage long sys_access(const char * filename, int mode)
{
struct nameidata nd;
int old_fsuid, old_fsgid;
kernel_cap_t old_cap;
int res;
if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
return -EINVAL;
old_fsuid = current->fsuid;
old_fsgid = current->fsgid;
old_cap = current->cap_effective;
current->fsuid = current->uid;
current->fsgid = current->gid;
/* Clear the capabilities if we switch to a non-root user */
if (current->uid)
cap_clear(current->cap_effective);
else
current->cap_effective = current->cap_permitted;
res = user_path_walk(filename, &nd);
if (!res) {
res = permission(nd.dentry->d_inode, mode);
/* SuS v2 requires we report a read only fs too */
if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode)
&& !special_file(nd.dentry->d_inode->i_mode))
res = -EROFS;
path_release(&nd);
}
current->fsuid = old_fsuid;
current->fsgid = old_fsgid;
current->cap_effective = old_cap;
return res;
}
asmlinkage long sys_chdir(const char * filename)
{
int error;
struct nameidata nd;
char *name;
name = getname(filename);
error = PTR_ERR(name);
if (IS_ERR(name))
goto out;
error = 0;
if (path_init(name,LOOKUP_POSITIVE|LOOKUP_FOLLOW|LOOKUP_DIRECTORY,&nd))
error = path_walk(name, &nd);
putname(name);
if (error)
goto out;
error = permission(nd.dentry->d_inode,MAY_EXEC);
if (error)
goto dput_and_out;
set_fs_pwd(current->fs, nd.mnt, nd.dentry);
dput_and_out:
path_release(&nd);
out:
return error;
}
asmlinkage long sys_fchdir(unsigned int fd)
{
struct file *file;
struct dentry *dentry;
struct inode *inode;
struct vfsmount *mnt;
int error;
error = -EBADF;
file = fget(fd);
if (!file)
goto out;
dentry = file->f_dentry;
mnt = file->f_vfsmnt;
inode = dentry->d_inode;
error = -ENOTDIR;
if (!S_ISDIR(inode->i_mode))
goto out_putf;
error = permission(inode, MAY_EXEC);
if (!error)
set_fs_pwd(current->fs, mnt, dentry);
out_putf:
fput(file);
out:
return error;
}
asmlinkage long sys_chroot(const char * filename)
{
int error;
struct nameidata nd;
char *name;
name = getname(filename);
error = PTR_ERR(name);
if (IS_ERR(name))
goto out;
path_init(name, LOOKUP_POSITIVE | LOOKUP_FOLLOW |
LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd);
error = path_walk(name, &nd);
putname(name);
if (error)
goto out;
error = permission(nd.dentry->d_inode,MAY_EXEC);
if (error)
goto dput_and_out;
error = -EPERM;
if (!capable(CAP_SYS_CHROOT))
goto dput_and_out;
set_fs_root(current->fs, nd.mnt, nd.dentry);
set_fs_altroot();
error = 0;
dput_and_out:
path_release(&nd);
out:
return error;
}
asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
{
struct inode * inode;
struct dentry * dentry;
struct file * file;
int err = -EBADF;
struct iattr newattrs;
file = fget(fd);
if (!file)
goto out;
dentry = file->f_dentry;
inode = dentry->d_inode;
err = -EROFS;
if (IS_RDONLY(inode))
goto out_putf;
err = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
goto out_putf;
if (mode == (mode_t) -1)
mode = inode->i_mode;
newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
err = notify_change(dentry, &newattrs);
out_putf:
fput(file);
out:
return err;
}
asmlinkage long sys_chmod(const char * filename, mode_t mode)
{
struct nameidata nd;
struct inode * inode;
int error;
struct iattr newattrs;
error = user_path_walk(filename, &nd);
if (error)
goto out;
inode = nd.dentry->d_inode;
error = -EROFS;
if (IS_RDONLY(inode))
goto dput_and_out;
error = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
goto dput_and_out;
if (mode == (mode_t) -1)
mode = inode->i_mode;
newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
error = notify_change(nd.dentry, &newattrs);
dput_and_out:
path_release(&nd);
out:
return error;
}
static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
{
struct inode * inode;
int error;
struct iattr newattrs;
error = -ENOENT;
if (!(inode = dentry->d_inode)) {
printk(KERN_ERR "chown_common: NULL inode\n");
goto out;
}
error = -EROFS;
if (IS_RDONLY(inode))
goto out;
error = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
goto out;
if (user == (uid_t) -1)
user = inode->i_uid;
if (group == (gid_t) -1)
group = inode->i_gid;
newattrs.ia_mode = inode->i_mode;
newattrs.ia_uid = user;
newattrs.ia_gid = group;
newattrs.ia_valid = ATTR_UID | ATTR_GID | ATTR_CTIME;
/*
* If the user or group of a non-directory has been changed by a
* non-root user, remove the setuid bit.
* 19981026 David C Niemi <niemi@tux.org>
*
* Changed this to apply to all users, including root, to avoid
* some races. This is the behavior we had in 2.0. The check for
* non-root was definitely wrong for 2.2 anyway, as it should
* have been using CAP_FSETID rather than fsuid -- 19990830 SD.
*/
if ((inode->i_mode & S_ISUID) == S_ISUID &&
!S_ISDIR(inode->i_mode))
{
newattrs.ia_mode &= ~S_ISUID;
newattrs.ia_valid |= ATTR_MODE;
}
/*
* Likewise, if the user or group of a non-directory has been changed
* by a non-root user, remove the setgid bit UNLESS there is no group
* execute bit (this would be a file marked for mandatory locking).
* 19981026 David C Niemi <niemi@tux.org>
*
* Removed the fsuid check (see the comment above) -- 19990830 SD.
*/
if (((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
&& !S_ISDIR(inode->i_mode))
{
newattrs.ia_mode &= ~S_ISGID;
newattrs.ia_valid |= ATTR_MODE;
}
error = notify_change(dentry, &newattrs);
out:
return error;
}
asmlinkage long sys_chown(const char * filename, uid_t user, gid_t group)
{
struct nameidata nd;
int error;
error = user_path_walk(filename, &nd);
if (!error) {
error = chown_common(nd.dentry, user, group);
path_release(&nd);
}
return error;
}
asmlinkage long sys_lchown(const char * filename, uid_t user, gid_t group)
{
struct nameidata nd;
int error;
error = user_path_walk_link(filename, &nd);
if (!error) {
error = chown_common(nd.dentry, user, group);
path_release(&nd);
}
return error;
}
asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
{
struct file * file;
int error = -EBADF;
file = fget(fd);
if (file) {
error = chown_common(file->f_dentry, user, group);
fput(file);
}
return error;
}
/*
* Note that while the flag value (low two bits) for sys_open means:
* 00 - read-only
* 01 - write-only
* 10 - read-write
* 11 - special
* it is changed into
* 00 - no permissions needed
* 01 - read-permission
* 10 - write-permission
* 11 - read-write
* for the internal routines (ie open_namei()/follow_link() etc). 00 is
* used by symlinks.
*/
struct file *filp_open(const char * filename, int flags, int mode)
{
int namei_flags, error;
struct nameidata nd;
namei_flags = flags;
if ((namei_flags+1) & O_ACCMODE)
namei_flags++;
if (namei_flags & O_TRUNC)
namei_flags |= 2;
error = open_namei(filename, namei_flags, mode, &nd);
if (!error)
return dentry_open(nd.dentry, nd.mnt, flags);
return ERR_PTR(error);
}
struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
{
struct file * f;
struct inode *inode;
static LIST_HEAD(kill_list);
int error;
error = -ENFILE;
f = get_empty_filp();
if (!f)
goto cleanup_dentry;
f->f_flags = flags;
f->f_mode = (flags+1) & O_ACCMODE;
inode = dentry->d_inode;
if (f->f_mode & FMODE_WRITE) {
error = get_write_access(inode);
if (error)
goto cleanup_file;
}
f->f_dentry = dentry;
f->f_vfsmnt = mnt;
f->f_pos = 0;
f->f_reada = 0;
f->f_op = fops_get(inode->i_fop);
file_move(f, &inode->i_sb->s_files);
/* preallocate kiobuf for O_DIRECT */
f->f_iobuf = NULL;
f->f_iobuf_lock = 0;
if (f->f_flags & O_DIRECT) {
error = alloc_kiovec(1, &f->f_iobuf);
if (error)
goto cleanup_all;
}
if (f->f_op && f->f_op->open) {
error = f->f_op->open(inode,f);
if (error)
goto cleanup_all;
}
f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
return f;
cleanup_all:
if (f->f_iobuf)
free_kiovec(1, &f->f_iobuf);
fops_put(f->f_op);
if (f->f_mode & FMODE_WRITE)
put_write_access(inode);
file_move(f, &kill_list); /* out of the way.. */
f->f_dentry = NULL;
f->f_vfsmnt = NULL;
cleanup_file:
put_filp(f);
cleanup_dentry:
dput(dentry);
mntput(mnt);
return ERR_PTR(error);
}
/*
* Find an empty file descriptor entry, and mark it busy.
*/
int get_unused_fd(void)
{
struct files_struct * files = current->files;
int fd, error;
error = -EMFILE;
write_lock(&files->file_lock);
repeat:
fd = find_next_zero_bit(files->open_fds,
files->max_fdset,
files->next_fd);
/*
* N.B. For clone tasks sharing a files structure, this test
* will limit the total number of files that can be opened.
*/
if (fd >= current->rlim[RLIMIT_NOFILE].rlim_cur)
goto out;
/* Do we need to expand the fdset array? */
if (fd >= files->max_fdset) {
error = expand_fdset(files, fd);
if (!error) {
error = -EMFILE;
goto repeat;
}
goto out;
}
/*
* Check whether we need to expand the fd array.
*/
if (fd >= files->max_fds) {
error = expand_fd_array(files, fd);
if (!error) {
error = -EMFILE;
goto repeat;
}
goto out;
}
FD_SET(fd, files->open_fds);
FD_CLR(fd, files->close_on_exec);
files->next_fd = fd + 1;
#if 1
/* Sanity check */
if (files->fd[fd] != NULL) {
printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
files->fd[fd] = NULL;
}
#endif
error = fd;
out:
write_unlock(&files->file_lock);
return error;
}
asmlinkage long sys_open(const char * filename, int flags, int mode)
{
char * tmp;
int fd, error;
#if BITS_PER_LONG != 32
flags |= O_LARGEFILE;
#endif
tmp = getname(filename);
fd = PTR_ERR(tmp);
if (!IS_ERR(tmp)) {
fd = get_unused_fd();
if (fd >= 0) {
struct file *f = filp_open(tmp, flags, mode);
error = PTR_ERR(f);
if (IS_ERR(f))
goto out_error;
fd_install(fd, f);
}
out:
putname(tmp);
}
return fd;
out_error:
put_unused_fd(fd);
fd = error;
goto out;
}
#ifndef __alpha__
/*
* For backward compatibility? Maybe this should be moved
* into arch/i386 instead?
*/
asmlinkage long sys_creat(const char * pathname, int mode)
{
return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
}
#endif
/*
* "id" is the POSIX thread ID. We use the
* files pointer for this..
*/
int filp_close(struct file *filp, fl_owner_t id)
{
int retval;
if (!file_count(filp)) {
printk(KERN_ERR "VFS: Close: file count is 0\n");
return 0;
}
retval = 0;
if (filp->f_op && filp->f_op->flush) {
lock_kernel();
retval = filp->f_op->flush(filp);
unlock_kernel();
}
fcntl_dirnotify(0, filp, 0);
locks_remove_posix(filp, id);
fput(filp);
return retval;
}
/*
* Careful here! We test whether the file pointer is NULL before
* releasing the fd. This ensures that one clone task can't release
* an fd while another clone is opening it.
*/
asmlinkage long sys_close(unsigned int fd)
{
struct file * filp;
struct files_struct *files = current->files;
write_lock(&files->file_lock);
if (fd >= files->max_fds)
goto out_unlock;
filp = files->fd[fd];
if (!filp)
goto out_unlock;
files->fd[fd] = NULL;
FD_CLR(fd, files->close_on_exec);
__put_unused_fd(files, fd);
write_unlock(&files->file_lock);
return filp_close(filp, files);
out_unlock:
write_unlock(&files->file_lock);
return -EBADF;
}
/*
* This routine simulates a hangup on the tty, to arrange that users
* are given clean terminals at login time.
*/
asmlinkage long sys_vhangup(void)
{
if (capable(CAP_SYS_TTY_CONFIG)) {
tty_vhangup(current->tty);
return 0;
}
return -EPERM;
}
/*
* Called when an inode is about to be open.
* We use this to disallow opening RW large files on 32bit systems if
* the caller didn't specify O_LARGEFILE. On 64bit systems we force
* on this flag in sys_open.
*/
int generic_file_open(struct inode * inode, struct file * filp)
{
if (!(filp->f_flags & O_LARGEFILE) && inode->i_size > MAX_NON_LFS)
return -EFBIG;
return 0;
}
EXPORT_SYMBOL(generic_file_open);
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