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-rw-r--r--fs/autofs4/dev-ioctl.c865
1 files changed, 865 insertions, 0 deletions
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
new file mode 100644
index 00000000000..63b7c7afe8d
--- /dev/null
+++ b/fs/autofs4/dev-ioctl.c
@@ -0,0 +1,865 @@
+/*
+ * Copyright 2008 Red Hat, Inc. All rights reserved.
+ * Copyright 2008 Ian Kent <raven@themaw.net>
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ */
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/namei.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/sched.h>
+#include <linux/compat.h>
+#include <linux/syscalls.h>
+#include <linux/smp_lock.h>
+#include <linux/magic.h>
+#include <linux/dcache.h>
+#include <linux/uaccess.h>
+
+#include "autofs_i.h"
+
+/*
+ * This module implements an interface for routing autofs ioctl control
+ * commands via a miscellaneous device file.
+ *
+ * The alternate interface is needed because we need to be able open
+ * an ioctl file descriptor on an autofs mount that may be covered by
+ * another mount. This situation arises when starting automount(8)
+ * or other user space daemon which uses direct mounts or offset
+ * mounts (used for autofs lazy mount/umount of nested mount trees),
+ * which have been left busy at at service shutdown.
+ */
+
+#define AUTOFS_DEV_IOCTL_SIZE sizeof(struct autofs_dev_ioctl)
+
+typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
+ struct autofs_dev_ioctl *);
+
+static int check_name(const char *name)
+{
+ if (!strchr(name, '/'))
+ return -EINVAL;
+ return 0;
+}
+
+/*
+ * Check a string doesn't overrun the chunk of
+ * memory we copied from user land.
+ */
+static int invalid_str(char *str, void *end)
+{
+ while ((void *) str <= end)
+ if (!*str++)
+ return 0;
+ return -EINVAL;
+}
+
+/*
+ * Check that the user compiled against correct version of autofs
+ * misc device code.
+ *
+ * As well as checking the version compatibility this always copies
+ * the kernel interface version out.
+ */
+static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
+{
+ int err = 0;
+
+ if ((AUTOFS_DEV_IOCTL_VERSION_MAJOR != param->ver_major) ||
+ (AUTOFS_DEV_IOCTL_VERSION_MINOR < param->ver_minor)) {
+ AUTOFS_WARN("ioctl control interface version mismatch: "
+ "kernel(%u.%u), user(%u.%u), cmd(%d)",
+ AUTOFS_DEV_IOCTL_VERSION_MAJOR,
+ AUTOFS_DEV_IOCTL_VERSION_MINOR,
+ param->ver_major, param->ver_minor, cmd);
+ err = -EINVAL;
+ }
+
+ /* Fill in the kernel version. */
+ param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
+ param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
+
+ return err;
+}
+
+/*
+ * Copy parameter control struct, including a possible path allocated
+ * at the end of the struct.
+ */
+static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
+{
+ struct autofs_dev_ioctl tmp, *ads;
+
+ if (copy_from_user(&tmp, in, sizeof(tmp)))
+ return ERR_PTR(-EFAULT);
+
+ if (tmp.size < sizeof(tmp))
+ return ERR_PTR(-EINVAL);
+
+ ads = kmalloc(tmp.size, GFP_KERNEL);
+ if (!ads)
+ return ERR_PTR(-ENOMEM);
+
+ if (copy_from_user(ads, in, tmp.size)) {
+ kfree(ads);
+ return ERR_PTR(-EFAULT);
+ }
+
+ return ads;
+}
+
+static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
+{
+ kfree(param);
+ return;
+}
+
+/*
+ * Check sanity of parameter control fields and if a path is present
+ * check that it has a "/" and is terminated.
+ */
+static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
+{
+ int err;
+
+ err = check_dev_ioctl_version(cmd, param);
+ if (err) {
+ AUTOFS_WARN("invalid device control module version "
+ "supplied for cmd(0x%08x)", cmd);
+ goto out;
+ }
+
+ if (param->size > sizeof(*param)) {
+ err = check_name(param->path);
+ if (err) {
+ AUTOFS_WARN("invalid path supplied for cmd(0x%08x)",
+ cmd);
+ goto out;
+ }
+
+ err = invalid_str(param->path,
+ (void *) ((size_t) param + param->size));
+ if (err) {
+ AUTOFS_WARN("invalid path supplied for cmd(0x%08x)",
+ cmd);
+ goto out;
+ }
+ }
+
+ err = 0;
+out:
+ return err;
+}
+
+/*
+ * Get the autofs super block info struct from the file opened on
+ * the autofs mount point.
+ */
+static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
+{
+ struct autofs_sb_info *sbi = NULL;
+ struct inode *inode;
+
+ if (f) {
+ inode = f->f_path.dentry->d_inode;
+ sbi = autofs4_sbi(inode->i_sb);
+ }
+ return sbi;
+}
+
+/* Return autofs module protocol version */
+static int autofs_dev_ioctl_protover(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ param->arg1 = sbi->version;
+ return 0;
+}
+
+/* Return autofs module protocol sub version */
+static int autofs_dev_ioctl_protosubver(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ param->arg1 = sbi->sub_version;
+ return 0;
+}
+
+/*
+ * Walk down the mount stack looking for an autofs mount that
+ * has the requested device number (aka. new_encode_dev(sb->s_dev).
+ */
+static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno)
+{
+ struct dentry *dentry;
+ struct inode *inode;
+ struct super_block *sb;
+ dev_t s_dev;
+ unsigned int err;
+
+ err = -ENOENT;
+
+ /* Lookup the dentry name at the base of our mount point */
+ dentry = d_lookup(nd->path.dentry, &nd->last);
+ if (!dentry)
+ goto out;
+
+ dput(nd->path.dentry);
+ nd->path.dentry = dentry;
+
+ /* And follow the mount stack looking for our autofs mount */
+ while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
+ inode = nd->path.dentry->d_inode;
+ if (!inode)
+ break;
+
+ sb = inode->i_sb;
+ s_dev = new_encode_dev(sb->s_dev);
+ if (devno == s_dev) {
+ if (sb->s_magic == AUTOFS_SUPER_MAGIC) {
+ err = 0;
+ break;
+ }
+ }
+ }
+out:
+ return err;
+}
+
+/*
+ * Walk down the mount stack looking for an autofs mount that
+ * has the requested mount type (ie. indirect, direct or offset).
+ */
+static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type)
+{
+ struct dentry *dentry;
+ struct autofs_info *ino;
+ unsigned int err;
+
+ err = -ENOENT;
+
+ /* Lookup the dentry name at the base of our mount point */
+ dentry = d_lookup(nd->path.dentry, &nd->last);
+ if (!dentry)
+ goto out;
+
+ dput(nd->path.dentry);
+ nd->path.dentry = dentry;
+
+ /* And follow the mount stack looking for our autofs mount */
+ while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
+ ino = autofs4_dentry_ino(nd->path.dentry);
+ if (ino && ino->sbi->type & type) {
+ err = 0;
+ break;
+ }
+ }
+out:
+ return err;
+}
+
+static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file)
+{
+ struct files_struct *files = current->files;
+ struct fdtable *fdt;
+
+ spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
+ BUG_ON(fdt->fd[fd] != NULL);
+ rcu_assign_pointer(fdt->fd[fd], file);
+ FD_SET(fd, fdt->close_on_exec);
+ spin_unlock(&files->file_lock);
+}
+
+
+/*
+ * Open a file descriptor on the autofs mount point corresponding
+ * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
+ */
+static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid)
+{
+ struct file *filp;
+ struct nameidata nd;
+ int err, fd;
+
+ fd = get_unused_fd();
+ if (likely(fd >= 0)) {
+ /* Get nameidata of the parent directory */
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ /*
+ * Search down, within the parent, looking for an
+ * autofs super block that has the device number
+ * corresponding to the autofs fs we want to open.
+ */
+ err = autofs_dev_ioctl_find_super(&nd, devid);
+ if (err) {
+ path_put(&nd.path);
+ goto out;
+ }
+
+ filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
+ current_cred());
+ if (IS_ERR(filp)) {
+ err = PTR_ERR(filp);
+ goto out;
+ }
+
+ autofs_dev_ioctl_fd_install(fd, filp);
+ }
+
+ return fd;
+
+out:
+ put_unused_fd(fd);
+ return err;
+}
+
+/* Open a file descriptor on an autofs mount point */
+static int autofs_dev_ioctl_openmount(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ const char *path;
+ dev_t devid;
+ int err, fd;
+
+ /* param->path has already been checked */
+ if (!param->arg1)
+ return -EINVAL;
+
+ param->ioctlfd = -1;
+
+ path = param->path;
+ devid = param->arg1;
+
+ err = 0;
+ fd = autofs_dev_ioctl_open_mountpoint(path, devid);
+ if (unlikely(fd < 0)) {
+ err = fd;
+ goto out;
+ }
+
+ param->ioctlfd = fd;
+out:
+ return err;
+}
+
+/* Close file descriptor allocated above (user can also use close(2)). */
+static int autofs_dev_ioctl_closemount(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ return sys_close(param->ioctlfd);
+}
+
+/*
+ * Send "ready" status for an existing wait (either a mount or an expire
+ * request).
+ */
+static int autofs_dev_ioctl_ready(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ autofs_wqt_t token;
+
+ token = (autofs_wqt_t) param->arg1;
+ return autofs4_wait_release(sbi, token, 0);
+}
+
+/*
+ * Send "fail" status for an existing wait (either a mount or an expire
+ * request).
+ */
+static int autofs_dev_ioctl_fail(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ autofs_wqt_t token;
+ int status;
+
+ token = (autofs_wqt_t) param->arg1;
+ status = param->arg2 ? param->arg2 : -ENOENT;
+ return autofs4_wait_release(sbi, token, status);
+}
+
+/*
+ * Set the pipe fd for kernel communication to the daemon.
+ *
+ * Normally this is set at mount using an option but if we
+ * are reconnecting to a busy mount then we need to use this
+ * to tell the autofs mount about the new kernel pipe fd. In
+ * order to protect mounts against incorrectly setting the
+ * pipefd we also require that the autofs mount be catatonic.
+ *
+ * This also sets the process group id used to identify the
+ * controlling process (eg. the owning automount(8) daemon).
+ */
+static int autofs_dev_ioctl_setpipefd(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ int pipefd;
+ int err = 0;
+
+ if (param->arg1 == -1)
+ return -EINVAL;
+
+ pipefd = param->arg1;
+
+ mutex_lock(&sbi->wq_mutex);
+ if (!sbi->catatonic) {
+ mutex_unlock(&sbi->wq_mutex);
+ return -EBUSY;
+ } else {
+ struct file *pipe = fget(pipefd);
+ if (!pipe->f_op || !pipe->f_op->write) {
+ err = -EPIPE;
+ fput(pipe);
+ goto out;
+ }
+ sbi->oz_pgrp = task_pgrp_nr(current);
+ sbi->pipefd = pipefd;
+ sbi->pipe = pipe;
+ sbi->catatonic = 0;
+ }
+out:
+ mutex_unlock(&sbi->wq_mutex);
+ return err;
+}
+
+/*
+ * Make the autofs mount point catatonic, no longer responsive to
+ * mount requests. Also closes the kernel pipe file descriptor.
+ */
+static int autofs_dev_ioctl_catatonic(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ autofs4_catatonic_mode(sbi);
+ return 0;
+}
+
+/* Set the autofs mount timeout */
+static int autofs_dev_ioctl_timeout(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ unsigned long timeout;
+
+ timeout = param->arg1;
+ param->arg1 = sbi->exp_timeout / HZ;
+ sbi->exp_timeout = timeout * HZ;
+ return 0;
+}
+
+/*
+ * Return the uid and gid of the last request for the mount
+ *
+ * When reconstructing an autofs mount tree with active mounts
+ * we need to re-connect to mounts that may have used the original
+ * process uid and gid (or string variations of them) for mount
+ * lookups within the map entry.
+ */
+static int autofs_dev_ioctl_requester(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ struct autofs_info *ino;
+ struct nameidata nd;
+ const char *path;
+ dev_t devid;
+ int err = -ENOENT;
+
+ if (param->size <= sizeof(*param)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ path = param->path;
+ devid = sbi->sb->s_dev;
+
+ param->arg1 = param->arg2 = -1;
+
+ /* Get nameidata of the parent directory */
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ err = autofs_dev_ioctl_find_super(&nd, devid);
+ if (err)
+ goto out_release;
+
+ ino = autofs4_dentry_ino(nd.path.dentry);
+ if (ino) {
+ err = 0;
+ autofs4_expire_wait(nd.path.dentry);
+ spin_lock(&sbi->fs_lock);
+ param->arg1 = ino->uid;
+ param->arg2 = ino->gid;
+ spin_unlock(&sbi->fs_lock);
+ }
+
+out_release:
+ path_put(&nd.path);
+out:
+ return err;
+}
+
+/*
+ * Call repeatedly until it returns -EAGAIN, meaning there's nothing
+ * more that can be done.
+ */
+static int autofs_dev_ioctl_expire(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ struct dentry *dentry;
+ struct vfsmount *mnt;
+ int err = -EAGAIN;
+ int how;
+
+ how = param->arg1;
+ mnt = fp->f_path.mnt;
+
+ if (sbi->type & AUTOFS_TYPE_TRIGGER)
+ dentry = autofs4_expire_direct(sbi->sb, mnt, sbi, how);
+ else
+ dentry = autofs4_expire_indirect(sbi->sb, mnt, sbi, how);
+
+ if (dentry) {
+ struct autofs_info *ino = autofs4_dentry_ino(dentry);
+
+ /*
+ * This is synchronous because it makes the daemon a
+ * little easier
+ */
+ err = autofs4_wait(sbi, dentry, NFY_EXPIRE);
+
+ spin_lock(&sbi->fs_lock);
+ if (ino->flags & AUTOFS_INF_MOUNTPOINT) {
+ ino->flags &= ~AUTOFS_INF_MOUNTPOINT;
+ sbi->sb->s_root->d_mounted++;
+ }
+ ino->flags &= ~AUTOFS_INF_EXPIRING;
+ complete_all(&ino->expire_complete);
+ spin_unlock(&sbi->fs_lock);
+ dput(dentry);
+ }
+
+ return err;
+}
+
+/* Check if autofs mount point is in use */
+static int autofs_dev_ioctl_askumount(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ param->arg1 = 0;
+ if (may_umount(fp->f_path.mnt))
+ param->arg1 = 1;
+ return 0;
+}
+
+/*
+ * Check if the given path is a mountpoint.
+ *
+ * If we are supplied with the file descriptor of an autofs
+ * mount we're looking for a specific mount. In this case
+ * the path is considered a mountpoint if it is itself a
+ * mountpoint or contains a mount, such as a multi-mount
+ * without a root mount. In this case we return 1 if the
+ * path is a mount point and the super magic of the covering
+ * mount if there is one or 0 if it isn't a mountpoint.
+ *
+ * If we aren't supplied with a file descriptor then we
+ * lookup the nameidata of the path and check if it is the
+ * root of a mount. If a type is given we are looking for
+ * a particular autofs mount and if we don't find a match
+ * we return fail. If the located nameidata path is the
+ * root of a mount we return 1 along with the super magic
+ * of the mount or 0 otherwise.
+ *
+ * In both cases the the device number (as returned by
+ * new_encode_dev()) is also returned.
+ */
+static int autofs_dev_ioctl_ismountpoint(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ struct nameidata nd;
+ const char *path;
+ unsigned int type;
+ int err = -ENOENT;
+
+ if (param->size <= sizeof(*param)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ path = param->path;
+ type = param->arg1;
+
+ param->arg1 = 0;
+ param->arg2 = 0;
+
+ if (!fp || param->ioctlfd == -1) {
+ if (type == AUTOFS_TYPE_ANY) {
+ struct super_block *sb;
+
+ err = path_lookup(path, LOOKUP_FOLLOW, &nd);
+ if (err)
+ goto out;
+
+ sb = nd.path.dentry->d_sb;
+ param->arg1 = new_encode_dev(sb->s_dev);
+ } else {
+ struct autofs_info *ino;
+
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ err = autofs_dev_ioctl_find_sbi_type(&nd, type);
+ if (err)
+ goto out_release;
+
+ ino = autofs4_dentry_ino(nd.path.dentry);
+ param->arg1 = autofs4_get_dev(ino->sbi);
+ }
+
+ err = 0;
+ if (nd.path.dentry->d_inode &&
+ nd.path.mnt->mnt_root == nd.path.dentry) {
+ err = 1;
+ param->arg2 = nd.path.dentry->d_inode->i_sb->s_magic;
+ }
+ } else {
+ dev_t devid = new_encode_dev(sbi->sb->s_dev);
+
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ err = autofs_dev_ioctl_find_super(&nd, devid);
+ if (err)
+ goto out_release;
+
+ param->arg1 = autofs4_get_dev(sbi);
+
+ err = have_submounts(nd.path.dentry);
+
+ if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) {
+ if (follow_down(&nd.path.mnt, &nd.path.dentry)) {
+ struct inode *inode = nd.path.dentry->d_inode;
+ param->arg2 = inode->i_sb->s_magic;
+ }
+ }
+ }
+
+out_release:
+ path_put(&nd.path);
+out:
+ return err;
+}
+
+/*
+ * Our range of ioctl numbers isn't 0 based so we need to shift
+ * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
+ * lookup.
+ */
+#define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
+
+static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
+{
+ static struct {
+ int cmd;
+ ioctl_fn fn;
+ } _ioctls[] = {
+ {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL},
+ {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD),
+ autofs_dev_ioctl_protover},
+ {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD),
+ autofs_dev_ioctl_protosubver},
+ {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD),
+ autofs_dev_ioctl_openmount},
+ {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD),
+ autofs_dev_ioctl_closemount},
+ {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD),
+ autofs_dev_ioctl_ready},
+ {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD),
+ autofs_dev_ioctl_fail},
+ {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD),
+ autofs_dev_ioctl_setpipefd},
+ {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD),
+ autofs_dev_ioctl_catatonic},
+ {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD),
+ autofs_dev_ioctl_timeout},
+ {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD),
+ autofs_dev_ioctl_requester},
+ {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD),
+ autofs_dev_ioctl_expire},
+ {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD),
+ autofs_dev_ioctl_askumount},
+ {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD),
+ autofs_dev_ioctl_ismountpoint}
+ };
+ unsigned int idx = cmd_idx(cmd);
+
+ return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn;
+}
+
+/* ioctl dispatcher */
+static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user)
+{
+ struct autofs_dev_ioctl *param;
+ struct file *fp;
+ struct autofs_sb_info *sbi;
+ unsigned int cmd_first, cmd;
+ ioctl_fn fn = NULL;
+ int err = 0;
+
+ /* only root can play with this */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
+ cmd = _IOC_NR(command);
+
+ if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
+ cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) {
+ return -ENOTTY;
+ }
+
+ /* Copy the parameters into kernel space. */
+ param = copy_dev_ioctl(user);
+ if (IS_ERR(param))
+ return PTR_ERR(param);
+
+ err = validate_dev_ioctl(command, param);
+ if (err)
+ goto out;
+
+ /* The validate routine above always sets the version */
+ if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD)
+ goto done;
+
+ fn = lookup_dev_ioctl(cmd);
+ if (!fn) {
+ AUTOFS_WARN("unknown command 0x%08x", command);
+ return -ENOTTY;
+ }
+
+ fp = NULL;
+ sbi = NULL;
+
+ /*
+ * For obvious reasons the openmount can't have a file
+ * descriptor yet. We don't take a reference to the
+ * file during close to allow for immediate release.
+ */
+ if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
+ cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
+ fp = fget(param->ioctlfd);
+ if (!fp) {
+ if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
+ goto cont;
+ err = -EBADF;
+ goto out;
+ }
+
+ if (!fp->f_op) {
+ err = -ENOTTY;
+ fput(fp);
+ goto out;
+ }
+
+ sbi = autofs_dev_ioctl_sbi(fp);
+ if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
+ err = -EINVAL;
+ fput(fp);
+ goto out;
+ }
+
+ /*
+ * Admin needs to be able to set the mount catatonic in
+ * order to be able to perform the re-open.
+ */
+ if (!autofs4_oz_mode(sbi) &&
+ cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
+ err = -EACCES;
+ fput(fp);
+ goto out;
+ }
+ }
+cont:
+ err = fn(fp, sbi, param);
+
+ if (fp)
+ fput(fp);
+done:
+ if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
+ err = -EFAULT;
+out:
+ free_dev_ioctl(param);
+ return err;
+}
+
+static long autofs_dev_ioctl(struct file *file, uint command, ulong u)
+{
+ int err;
+ err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
+ return (long) err;
+}
+
+#ifdef CONFIG_COMPAT
+static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u)
+{
+ return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u));
+}
+#else
+#define autofs_dev_ioctl_compat NULL
+#endif
+
+static const struct file_operations _dev_ioctl_fops = {
+ .unlocked_ioctl = autofs_dev_ioctl,
+ .compat_ioctl = autofs_dev_ioctl_compat,
+ .owner = THIS_MODULE,
+};
+
+static struct miscdevice _autofs_dev_ioctl_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = AUTOFS_DEVICE_NAME,
+ .fops = &_dev_ioctl_fops
+};
+
+/* Register/deregister misc character device */
+int autofs_dev_ioctl_init(void)
+{
+ int r;
+
+ r = misc_register(&_autofs_dev_ioctl_misc);
+ if (r) {
+ AUTOFS_ERROR("misc_register failed for control device");
+ return r;
+ }
+
+ return 0;
+}
+
+void autofs_dev_ioctl_exit(void)
+{
+ misc_deregister(&_autofs_dev_ioctl_misc);
+ return;
+}
+