path: root/fs/autofs/inode.c

/* -*- linux-c -*- --------------------------------------------------------- *
 *
 * linux/fs/autofs/inode.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/kernel.h>
#include <linux/malloc.h>
#include <linux/file.h>
#include <linux/locks.h>
#include <asm/bitops.h>
#include "autofs_i.h"
#define __NO_VERSION__
#include <linux/module.h>

/*
 * Dummy functions - do we ever actually want to do
 * something here?
 */
static void autofs_put_inode(struct inode *inode)
{
}

static void autofs_delete_inode(struct inode *inode)
{
	inode->i_size = 0;
}

static void autofs_put_super(struct super_block *sb)
{
	struct autofs_sb_info *sbi =
		(struct autofs_sb_info *) sb->u.generic_sbp;
	unsigned int n;

	if ( !sbi->catatonic )
		autofs_catatonic_mode(sbi); /* Free wait queues, close pipe */

	autofs_hash_nuke(&sbi->dirhash);
	for ( n = 0 ; n < AUTOFS_MAX_SYMLINKS ; n++ ) {
		if ( test_bit(n, sbi->symlink_bitmap) )
			kfree(sbi->symlink[n].data);
	}

	kfree(sb->u.generic_sbp);

	DPRINTK(("autofs: shutting down\n"));
	
#ifdef MODULE
	MOD_DEC_USE_COUNT;
#endif
}

static int autofs_statfs(struct super_block *sb, struct statfs *buf, int bufsiz);
static void autofs_read_inode(struct inode *inode);
static void autofs_write_inode(struct inode *inode);

static struct super_operations autofs_sops = {
	autofs_read_inode,
	autofs_write_inode,
	autofs_put_inode,
	autofs_delete_inode,
	NULL,			/* notify_change */
	autofs_put_super,
	NULL,			/* write_super */
	autofs_statfs,
	NULL
};

static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid, pid_t *pgrp, int *minproto, int *maxproto)
{
	char *this_char, *value;
	
	*uid = current->uid;
	*gid = current->gid;
	*pgrp = current->pgrp;

	*minproto = *maxproto = AUTOFS_PROTO_VERSION;

	*pipefd = -1;

	if ( !options ) return 1;
	for (this_char = strtok(options,","); this_char; this_char = strtok(NULL,",")) {
		if ((value = strchr(this_char,'=')) != NULL)
			*value++ = 0;
		if (!strcmp(this_char,"fd")) {
			if (!value || !*value)
				return 1;
			*pipefd = simple_strtoul(value,&value,0);
			if (*value)
				return 1;
		}
		else if (!strcmp(this_char,"uid")) {
			if (!value || !*value)
				return 1;
			*uid = simple_strtoul(value,&value,0);
			if (*value)
				return 1;
		}
		else if (!strcmp(this_char,"gid")) {
			if (!value || !*value)
				return 1;
			*gid = simple_strtoul(value,&value,0);
			if (*value)
				return 1;
		}
		else if (!strcmp(this_char,"pgrp")) {
			if (!value || !*value)
				return 1;
			*pgrp = simple_strtoul(value,&value,0);
			if (*value)
				return 1;
		}
		else if (!strcmp(this_char,"minproto")) {
			if (!value || !*value)
				return 1;
			*minproto = simple_strtoul(value,&value,0);
			if (*value)
				return 1;
		}
		else if (!strcmp(this_char,"maxproto")) {
			if (!value || !*value)
				return 1;
			*maxproto = simple_strtoul(value,&value,0);
			if (*value)
				return 1;
		}
		else break;
	}
	return (*pipefd < 0);
}

struct super_block *autofs_read_super(struct super_block *s, void *data,
				      int silent)
{
	struct inode * root_inode;
	struct dentry * root;
	struct file * pipe;
	int pipefd;
	struct autofs_sb_info *sbi;
	int minproto, maxproto;

	MOD_INC_USE_COUNT;

	lock_super(s);
	/* Super block already completed? */
	if (s->s_root)
		goto out_unlock;

	sbi = (struct autofs_sb_info *) kmalloc(sizeof(struct autofs_sb_info), GFP_KERNEL);
	if ( !sbi )
		goto fail_unlock;
	DPRINTK(("autofs: starting up, sbi = %p\n",sbi));

	s->u.generic_sbp = sbi;
	sbi->magic = AUTOFS_SBI_MAGIC;
	sbi->catatonic = 0;
	sbi->exp_timeout = 0;
	sbi->oz_pgrp = current->pgrp;
	autofs_initialize_hash(&sbi->dirhash);
	sbi->queues = NULL;
	memset(sbi->symlink_bitmap, 0, sizeof(u32)*AUTOFS_SYMLINK_BITMAP_LEN);
	sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = AUTOFS_SUPER_MAGIC;
	s->s_op = &autofs_sops;
	s->s_root = NULL;
	unlock_super(s); /* shouldn't we keep it locked a while longer? */

	/*
	 * Get the root inode and dentry, but defer checking for errors.
	 */
	root_inode = iget(s, AUTOFS_ROOT_INO);
	root = d_alloc_root(root_inode, NULL);
	pipe = NULL;

	/*
	 * Check whether somebody else completed the super block.
	 */
	if (s->s_root)
		goto out_dput;

	if (!root)
		goto fail_iput;

	/* Can this call block? */
	if ( parse_options(data,&pipefd,&root_inode->i_uid,&root_inode->i_gid,&sbi->oz_pgrp,&minproto,&maxproto) ) {
		printk("autofs: called with bogus options\n");
		goto fail_dput;
	}

	/* Couldn't this be tested earlier? */
	if ( minproto > AUTOFS_PROTO_VERSION || 
	     maxproto < AUTOFS_PROTO_VERSION ) {
		printk("autofs: kernel does not match daemon version\n");
		goto fail_dput;
	}

	DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, sbi->oz_pgrp));
	pipe = fget(pipefd);
	/*
	 * Check whether somebody else completed the super block.
	 */
	if (s->s_root)
		goto out_fput;
	
	if ( !pipe ) {
		printk("autofs: could not open pipe file descriptor\n");
		goto fail_dput;
	}
	if ( !pipe->f_op || !pipe->f_op->write )
		goto fail_fput;
	sbi->pipe = pipe;

	/*
	 * Success! Install the root dentry now to indicate completion.
	 */
	s->s_root = root;
	return s;

	/*
	 * Success ... somebody else completed the super block for us. 
	 */ 
out_unlock:
	unlock_super(s);
	goto out_dec;
out_fput:
	if (pipe)
		fput(pipe);
out_dput:
	if (root)
		dput(root);
	else
		iput(root_inode);
out_dec:
	MOD_DEC_USE_COUNT;
	return s;
	
	/*
	 * Failure ... clear the s_dev slot and clean up.
	 */
fail_fput:
	printk("autofs: pipe file descriptor does not contain proper ops\n");
	/*
	 * fput() can block, so we clear the super block first.
	 */
	s->s_dev = 0;
	fput(pipe);
	/* fall through */
fail_dput:
	/*
	 * dput() can block, so we clear the super block first.
	 */
	s->s_dev = 0;
	dput(root);
	goto fail_free;
fail_iput:
	printk("autofs: get root dentry failed\n");
	/*
	 * iput() can block, so we clear the super block first.
	 */
	s->s_dev = 0;
	iput(root_inode);
fail_free:
	kfree(sbi);
	goto fail_dec;
fail_unlock:
	unlock_super(s);
fail_dec:
	s->s_dev = 0;
	MOD_DEC_USE_COUNT;
	return NULL;
}

static int autofs_statfs(struct super_block *sb, struct statfs *buf, int bufsiz)
{
	struct statfs tmp;

	tmp.f_type = AUTOFS_SUPER_MAGIC;
	tmp.f_bsize = 1024;
	tmp.f_blocks = 0;
	tmp.f_bfree = 0;
	tmp.f_bavail = 0;
	tmp.f_files = 0;
	tmp.f_ffree = 0;
	tmp.f_namelen = NAME_MAX;
	return copy_to_user(buf, &tmp, bufsiz) ? -EFAULT : 0;
}

static void autofs_read_inode(struct inode *inode)
{
	ino_t ino = inode->i_ino;
	unsigned int n;
	struct autofs_sb_info *sbi =
		(struct autofs_sb_info *) inode->i_sb->u.generic_sbp;

	inode->i_op = NULL;
	inode->i_mode = 0;
	inode->i_nlink = 2;
	inode->i_size = 0;
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	inode->i_blocks = 0;
	inode->i_blksize = 1024;

	if ( ino == AUTOFS_ROOT_INO ) {
		inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
		inode->i_op = &autofs_root_inode_operations;
		inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
		return;
	} 
	
	inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
	inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
	
	if ( ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO ) {
		/* Symlink inode - should be in symlink list */
		struct autofs_symlink *sl;

		n = ino - AUTOFS_FIRST_SYMLINK;
		if ( n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
			printk("autofs: Looking for bad symlink inode 0x%08x\n", (unsigned int) ino);
			return;
		}
		
		inode->i_op = &autofs_symlink_inode_operations;
		sl = &sbi->symlink[n];
		inode->u.generic_ip = sl;
		inode->i_mode = S_IFLNK | S_IRWXUGO;
		inode->i_mtime = inode->i_ctime = sl->mtime;
		inode->i_size = sl->len;
		inode->i_nlink = 1;
	} else {
		/* All non-root directory inodes look the same */
		inode->i_op = &autofs_dir_inode_operations;
		inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
	}
}

static void autofs_write_inode(struct inode *inode)
{
}