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/* -*- linux-c -*- --------------------------------------------------------- *
*
* linux/fs/autofs/root.c
*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
*
* 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/errno.h>
#include <linux/stat.h>
#include <linux/param.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include "autofs_i.h"
static int autofs_root_readdir(struct file *,void *,filldir_t);
static struct dentry *autofs_root_lookup(struct inode *,struct dentry *);
static int autofs_root_symlink(struct inode *,struct dentry *,const char *);
static int autofs_root_unlink(struct inode *,struct dentry *);
static int autofs_root_rmdir(struct inode *,struct dentry *);
static int autofs_root_mkdir(struct inode *,struct dentry *,int);
static int autofs_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
struct file_operations autofs_root_operations = {
read: generic_read_dir,
readdir: autofs_root_readdir,
ioctl: autofs_root_ioctl,
};
struct inode_operations autofs_root_inode_operations = {
lookup: autofs_root_lookup,
unlink: autofs_root_unlink,
symlink: autofs_root_symlink,
mkdir: autofs_root_mkdir,
rmdir: autofs_root_rmdir,
};
static int autofs_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct autofs_dir_ent *ent = NULL;
struct autofs_dirhash *dirhash;
struct autofs_sb_info *sbi;
struct inode * inode = filp->f_dentry->d_inode;
off_t onr, nr;
sbi = autofs_sbi(inode->i_sb);
dirhash = &sbi->dirhash;
nr = filp->f_pos;
switch(nr)
{
case 0:
if (filldir(dirent, ".", 1, nr, inode->i_ino, DT_DIR) < 0)
return 0;
filp->f_pos = ++nr;
/* fall through */
case 1:
if (filldir(dirent, "..", 2, nr, inode->i_ino, DT_DIR) < 0)
return 0;
filp->f_pos = ++nr;
/* fall through */
default:
while ( onr = nr, ent = autofs_hash_enum(dirhash,&nr,ent) ) {
if ( !ent->dentry || d_mountpoint(ent->dentry) ) {
if (filldir(dirent,ent->name,ent->len,onr,ent->ino,DT_UNKNOWN) < 0)
return 0;
filp->f_pos = nr;
}
}
break;
}
return 0;
}
static int try_to_fill_dentry(struct dentry *dentry, struct super_block *sb, struct autofs_sb_info *sbi)
{
struct inode * inode;
struct autofs_dir_ent *ent;
int status = 0;
if ( !(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) ) {
do {
if ( status && dentry->d_inode ) {
if ( status != -ENOENT )
printk("autofs warning: lookup failure on positive dentry, status = %d, name = %s\n", status, dentry->d_name.name);
return 0; /* Try to get the kernel to invalidate this dentry */
}
/* Turn this into a real negative dentry? */
if (status == -ENOENT) {
dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
return 1;
} else if (status) {
/* Return a negative dentry, but leave it "pending" */
return 1;
}
status = autofs_wait(sbi, &dentry->d_name);
} while (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) );
}
/* Abuse this field as a pointer to the directory entry, used to
find the expire list pointers */
dentry->d_time = (unsigned long) ent;
if (!dentry->d_inode) {
inode = iget(sb, ent->ino);
if (!inode) {
/* Failed, but leave pending for next time */
return 1;
}
dentry->d_inode = inode;
}
/* If this is a directory that isn't a mount point, bitch at the
daemon and fix it in user space */
if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) {
return !autofs_wait(sbi, &dentry->d_name);
}
/* We don't update the usages for the autofs daemon itself, this
is necessary for recursive autofs mounts */
if ( !autofs_oz_mode(sbi) ) {
autofs_update_usage(&sbi->dirhash,ent);
}
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
return 1;
}
/*
* Revalidate is called on every cache lookup. Some of those
* cache lookups may actually happen while the dentry is not
* yet completely filled in, and revalidate has to delay such
* lookups..
*/
static int autofs_revalidate(struct dentry * dentry, int flags)
{
struct inode * dir;
struct autofs_sb_info *sbi;
struct autofs_dir_ent *ent;
int res;
lock_kernel();
dir = dentry->d_parent->d_inode;
sbi = autofs_sbi(dir->i_sb);
/* Pending dentry */
if ( dentry->d_flags & DCACHE_AUTOFS_PENDING ) {
if (autofs_oz_mode(sbi))
res = 1;
else
res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
unlock_kernel();
return res;
}
/* Negative dentry.. invalidate if "old" */
if (!dentry->d_inode) {
unlock_kernel();
return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
}
/* Check for a non-mountpoint directory */
if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) {
if (autofs_oz_mode(sbi))
res = 1;
else
res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
unlock_kernel();
return res;
}
/* Update the usage list */
if ( !autofs_oz_mode(sbi) ) {
ent = (struct autofs_dir_ent *) dentry->d_time;
if ( ent )
autofs_update_usage(&sbi->dirhash,ent);
}
unlock_kernel();
return 1;
}
static struct dentry_operations autofs_dentry_operations = {
d_revalidate: autofs_revalidate,
};
static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentry)
{
struct autofs_sb_info *sbi;
int oz_mode;
DPRINTK(("autofs_root_lookup: name = "));
autofs_say(dentry->d_name.name,dentry->d_name.len);
if (dentry->d_name.len > NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
sbi = autofs_sbi(dir->i_sb);
oz_mode = autofs_oz_mode(sbi);
DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
current->pid, current->pgrp, sbi->catatonic, oz_mode));
/*
* Mark the dentry incomplete, but add it. This is needed so
* that the VFS layer knows about the dentry, and we can count
* on catching any lookups through the revalidate.
*
* Let all the hard work be done by the revalidate function that
* needs to be able to do this anyway..
*
* We need to do this before we release the directory semaphore.
*/
dentry->d_op = &autofs_dentry_operations;
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
d_add(dentry, NULL);
up(&dir->i_sem);
autofs_revalidate(dentry, 0);
down(&dir->i_sem);
/*
* If we are still pending, check if we had to handle
* a signal. If so we can force a restart..
*/
if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
if (signal_pending(current))
return ERR_PTR(-ERESTARTNOINTR);
}
/*
* If this dentry is unhashed, then we shouldn't honour this
* lookup even if the dentry is positive. Returning ENOENT here
* doesn't do the right thing for all system calls, but it should
* be OK for the operations we permit from an autofs.
*/
if ( dentry->d_inode && d_unhashed(dentry) )
return ERR_PTR(-ENOENT);
return NULL;
}
static int autofs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
struct autofs_dirhash *dh = &sbi->dirhash;
struct autofs_dir_ent *ent;
unsigned int n;
int slsize;
struct autofs_symlink *sl;
DPRINTK(("autofs_root_symlink: %s <- ", symname));
autofs_say(dentry->d_name.name,dentry->d_name.len);
if ( !autofs_oz_mode(sbi) )
return -EACCES;
if ( autofs_hash_lookup(dh, &dentry->d_name) )
return -EEXIST;
n = find_first_zero_bit(sbi->symlink_bitmap,AUTOFS_MAX_SYMLINKS);
if ( n >= AUTOFS_MAX_SYMLINKS )
return -ENOSPC;
set_bit(n,sbi->symlink_bitmap);
sl = &sbi->symlink[n];
sl->len = strlen(symname);
sl->data = kmalloc(slsize = sl->len+1, GFP_KERNEL);
if ( !sl->data ) {
clear_bit(n,sbi->symlink_bitmap);
return -ENOSPC;
}
ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
if ( !ent ) {
kfree(sl->data);
clear_bit(n,sbi->symlink_bitmap);
return -ENOSPC;
}
ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
if ( !ent->name ) {
kfree(sl->data);
kfree(ent);
clear_bit(n,sbi->symlink_bitmap);
return -ENOSPC;
}
memcpy(sl->data,symname,slsize);
sl->mtime = CURRENT_TIME;
ent->ino = AUTOFS_FIRST_SYMLINK + n;
ent->hash = dentry->d_name.hash;
memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
ent->dentry = NULL; /* We don't keep the dentry for symlinks */
autofs_hash_insert(dh,ent);
d_instantiate(dentry, iget(dir->i_sb,ent->ino));
return 0;
}
/*
* NOTE!
*
* Normal filesystems would do a "d_delete()" to tell the VFS dcache
* that the file no longer exists. However, doing that means that the
* VFS layer can turn the dentry into a negative dentry, which we
* obviously do not want (we're dropping the entry not because it
* doesn't exist, but because it has timed out).
*
* Also see autofs_root_rmdir()..
*/
static int autofs_root_unlink(struct inode *dir, struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
struct autofs_dirhash *dh = &sbi->dirhash;
struct autofs_dir_ent *ent;
unsigned int n;
/* This allows root to remove symlinks */
if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
return -EACCES;
ent = autofs_hash_lookup(dh, &dentry->d_name);
if ( !ent )
return -ENOENT;
n = ent->ino - AUTOFS_FIRST_SYMLINK;
if ( n >= AUTOFS_MAX_SYMLINKS )
return -EISDIR; /* It's a directory, dummy */
if ( !test_bit(n,sbi->symlink_bitmap) )
return -EINVAL; /* Nonexistent symlink? Shouldn't happen */
dentry->d_time = (unsigned long)(struct autofs_dirhash *)NULL;
autofs_hash_delete(ent);
clear_bit(n,sbi->symlink_bitmap);
kfree(sbi->symlink[n].data);
d_drop(dentry);
return 0;
}
static int autofs_root_rmdir(struct inode *dir, struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
struct autofs_dirhash *dh = &sbi->dirhash;
struct autofs_dir_ent *ent;
if ( !autofs_oz_mode(sbi) )
return -EACCES;
ent = autofs_hash_lookup(dh, &dentry->d_name);
if ( !ent )
return -ENOENT;
if ( (unsigned int)ent->ino < AUTOFS_FIRST_DIR_INO )
return -ENOTDIR; /* Not a directory */
if ( ent->dentry != dentry ) {
printk("autofs_rmdir: odentry != dentry for entry %s\n", dentry->d_name.name);
}
dentry->d_time = (unsigned long)(struct autofs_dir_ent *)NULL;
autofs_hash_delete(ent);
dir->i_nlink--;
d_drop(dentry);
return 0;
}
static int autofs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
struct autofs_dirhash *dh = &sbi->dirhash;
struct autofs_dir_ent *ent;
ino_t ino;
if ( !autofs_oz_mode(sbi) )
return -EACCES;
ent = autofs_hash_lookup(dh, &dentry->d_name);
if ( ent )
return -EEXIST;
if ( sbi->next_dir_ino < AUTOFS_FIRST_DIR_INO ) {
printk("autofs: Out of inode numbers -- what the heck did you do??\n");
return -ENOSPC;
}
ino = sbi->next_dir_ino++;
ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
if ( !ent )
return -ENOSPC;
ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
if ( !ent->name ) {
kfree(ent);
return -ENOSPC;
}
ent->hash = dentry->d_name.hash;
memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
ent->ino = ino;
ent->dentry = dentry;
autofs_hash_insert(dh,ent);
dir->i_nlink++;
d_instantiate(dentry, iget(dir->i_sb,ino));
return 0;
}
/* Get/set timeout ioctl() operation */
static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
unsigned long *p)
{
unsigned long ntimeout;
if (get_user(ntimeout, p) ||
put_user(sbi->exp_timeout / HZ, p))
return -EFAULT;
if ( ntimeout > ULONG_MAX/HZ )
sbi->exp_timeout = 0;
else
sbi->exp_timeout = ntimeout * HZ;
return 0;
}
/* Return protocol version */
static inline int autofs_get_protover(int *p)
{
return put_user(AUTOFS_PROTO_VERSION, p);
}
/* Perform an expiry operation */
static inline int autofs_expire_run(struct super_block *sb,
struct autofs_sb_info *sbi,
struct vfsmount *mnt,
struct autofs_packet_expire *pkt_p)
{
struct autofs_dir_ent *ent;
struct autofs_packet_expire pkt;
memset(&pkt,0,sizeof pkt);
pkt.hdr.proto_version = AUTOFS_PROTO_VERSION;
pkt.hdr.type = autofs_ptype_expire;
if ( !sbi->exp_timeout ||
!(ent = autofs_expire(sb,sbi,mnt)) )
return -EAGAIN;
pkt.len = ent->len;
memcpy(pkt.name, ent->name, pkt.len);
pkt.name[pkt.len] = '\0';
if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) )
return -EFAULT;
return 0;
}
/*
* ioctl()'s on the root directory is the chief method for the daemon to
* generate kernel reactions
*/
static int autofs_root_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,current->pgrp));
if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
_IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
return -ENOTTY;
if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
return -EPERM;
switch(cmd) {
case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
return autofs_wait_release(sbi,(autofs_wqt_t)arg,0);
case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
return autofs_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
autofs_catatonic_mode(sbi);
return 0;
case AUTOFS_IOC_PROTOVER: /* Get protocol version */
return autofs_get_protover((int *)arg);
case AUTOFS_IOC_SETTIMEOUT:
return autofs_get_set_timeout(sbi,(unsigned long *)arg);
case AUTOFS_IOC_EXPIRE:
return autofs_expire_run(inode->i_sb, sbi, filp->f_vfsmnt,
(struct autofs_packet_expire *)arg);
default:
return -ENOSYS;
}
}
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