inode.c

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/* -*- c -*- --------------------------------------------------------------- *
 *
 * linux/fs/autofs/inode.c
 *
 *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
 *  Copyright 2005-2006 Ian Kent <[email protected]>
 *
 * 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/slab.h>
#include <linux/file.h>
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/parser.h>
#include <linux/bitops.h>
#include <linux/magic.h>
#include "autofs_i.h"
#include <linux/module.h>

struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
{
    struct autofs_info *ino = kzalloc(sizeof(*ino), GFP_KERNEL);
    if (ino) {
        INIT_LIST_HEAD(&ino->active);
        INIT_LIST_HEAD(&ino->expiring);
        ino->last_used = jiffies;
        ino->sbi = sbi;
    }
    return ino;
}

void autofs4_clean_ino(struct autofs_info *ino)
{
    ino->uid = 0;
    ino->gid = 0;
    ino->last_used = jiffies;
}

void autofs4_free_ino(struct autofs_info *ino)
{
    kfree(ino);
}

void autofs4_kill_sb(struct super_block *sb)
{
    struct autofs_sb_info *sbi = autofs4_sbi(sb);

    /*
     * In the event of a failure in get_sb_nodev the superblock
     * info is not present so nothing else has been setup, so
     * just call kill_anon_super when we are called from
     * deactivate_super.
     */
    if (!sbi)
        goto out_kill_sb;

    /* Free wait queues, close pipe */
    autofs4_catatonic_mode(sbi);

    sb->s_fs_info = NULL;
    kfree(sbi);

out_kill_sb:
    DPRINTK("shutting down");
    kill_litter_super(sb);
}

static int autofs4_show_options(struct seq_file *m, struct dentry *root)
{
    struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
    struct inode *root_inode = root->d_sb->s_root->d_inode;

    if (!sbi)
        return 0;

    seq_printf(m, ",fd=%d", sbi->pipefd);
    if (root_inode->i_uid != 0)
        seq_printf(m, ",uid=%u", root_inode->i_uid);
    if (root_inode->i_gid != 0)
        seq_printf(m, ",gid=%u", root_inode->i_gid);
    seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
    seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
    seq_printf(m, ",minproto=%d", sbi->min_proto);
    seq_printf(m, ",maxproto=%d", sbi->max_proto);

    if (autofs_type_offset(sbi->type))
        seq_printf(m, ",offset");
    else if (autofs_type_direct(sbi->type))
        seq_printf(m, ",direct");
    else
        seq_printf(m, ",indirect");

    return 0;
}

static void autofs4_evict_inode(struct inode *inode)
{
    clear_inode(inode);
    kfree(inode->i_private);
}

static const struct super_operations autofs4_sops = {
    .statfs     = simple_statfs,
    .show_options   = autofs4_show_options,
    .evict_inode    = autofs4_evict_inode,
};

enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
    Opt_indirect, Opt_direct, Opt_offset};

static const match_table_t tokens = {
    {Opt_fd, "fd=%u"},
    {Opt_uid, "uid=%u"},
    {Opt_gid, "gid=%u"},
    {Opt_pgrp, "pgrp=%u"},
    {Opt_minproto, "minproto=%u"},
    {Opt_maxproto, "maxproto=%u"},
    {Opt_indirect, "indirect"},
    {Opt_direct, "direct"},
    {Opt_offset, "offset"},
    {Opt_err, NULL}
};

static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
        pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
{
    char *p;
    substring_t args[MAX_OPT_ARGS];
    int option;

    *uid = current_uid();
    *gid = current_gid();
    *pgrp = task_pgrp_nr(current);

    *minproto = AUTOFS_MIN_PROTO_VERSION;
    *maxproto = AUTOFS_MAX_PROTO_VERSION;

    *pipefd = -1;

    if (!options)
        return 1;

    while ((p = strsep(&options, ",")) != NULL) {
        int token;
        if (!*p)
            continue;

        token = match_token(p, tokens, args);
        switch (token) {
        case Opt_fd:
            if (match_int(args, pipefd))
                return 1;
            break;
        case Opt_uid:
            if (match_int(args, &option))
                return 1;
            *uid = option;
            break;
        case Opt_gid:
            if (match_int(args, &option))
                return 1;
            *gid = option;
            break;
        case Opt_pgrp:
            if (match_int(args, &option))
                return 1;
            *pgrp = option;
            break;
        case Opt_minproto:
            if (match_int(args, &option))
                return 1;
            *minproto = option;
            break;
        case Opt_maxproto:
            if (match_int(args, &option))
                return 1;
            *maxproto = option;
            break;
        case Opt_indirect:
            set_autofs_type_indirect(type);
            break;
        case Opt_direct:
            set_autofs_type_direct(type);
            break;
        case Opt_offset:
            set_autofs_type_offset(type);
            break;
        default:
            return 1;
        }
    }
    return (*pipefd < 0);
}

int autofs4_fill_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;
    struct autofs_info *ino;

    sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
    if (!sbi)
        goto fail_unlock;
    DPRINTK("starting up, sbi = %p",sbi);

    s->s_fs_info = sbi;
    sbi->magic = AUTOFS_SBI_MAGIC;
    sbi->pipefd = -1;
    sbi->pipe = NULL;
    sbi->catatonic = 1;
    sbi->exp_timeout = 0;
    sbi->oz_pgrp = task_pgrp_nr(current);
    sbi->sb = s;
    sbi->version = 0;
    sbi->sub_version = 0;
    set_autofs_type_indirect(&sbi->type);
    sbi->min_proto = 0;
    sbi->max_proto = 0;
    mutex_init(&sbi->wq_mutex);
    mutex_init(&sbi->pipe_mutex);
    spin_lock_init(&sbi->fs_lock);
    sbi->queues = NULL;
    spin_lock_init(&sbi->lookup_lock);
    INIT_LIST_HEAD(&sbi->active_list);
    INIT_LIST_HEAD(&sbi->expiring_list);
    s->s_blocksize = 1024;
    s->s_blocksize_bits = 10;
    s->s_magic = AUTOFS_SUPER_MAGIC;
    s->s_op = &autofs4_sops;
    s->s_d_op = &autofs4_dentry_operations;
    s->s_time_gran = 1;

    /*
     * Get the root inode and dentry, but defer checking for errors.
     */
    ino = autofs4_new_ino(sbi);
    if (!ino)
        goto fail_free;
    root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
    root = d_make_root(root_inode);
    if (!root)
        goto fail_ino;
    pipe = NULL;

    root->d_fsdata = ino;

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

    if (autofs_type_trigger(sbi->type))
        __managed_dentry_set_managed(root);

    root_inode->i_fop = &autofs4_root_operations;
    root_inode->i_op = &autofs4_dir_inode_operations;

    /* Couldn't this be tested earlier? */
    if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
        sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
        printk("autofs: kernel does not match daemon version "
               "daemon (%d, %d) kernel (%d, %d)\n",
            sbi->min_proto, sbi->max_proto,
            AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
        goto fail_dput;
    }

    /* Establish highest kernel protocol version */
    if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
        sbi->version = AUTOFS_MAX_PROTO_VERSION;
    else
        sbi->version = sbi->max_proto;
    sbi->sub_version = AUTOFS_PROTO_SUBVERSION;

    DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
    pipe = fget(pipefd);
    
    if (!pipe) {
        printk("autofs: could not open pipe file descriptor\n");
        goto fail_dput;
    }
    if (autofs_prepare_pipe(pipe) < 0)
        goto fail_fput;
    sbi->pipe = pipe;
    sbi->pipefd = pipefd;
    sbi->catatonic = 0;

    /*
     * Success! Install the root dentry now to indicate completion.
     */
    s->s_root = root;
    return 0;
    
    /*
     * Failure ... clean up.
     */
fail_fput:
    printk("autofs: pipe file descriptor does not contain proper ops\n");
    fput(pipe);
    /* fall through */
fail_dput:
    dput(root);
    goto fail_free;
fail_ino:
    kfree(ino);
fail_free:
    kfree(sbi);
    s->s_fs_info = NULL;
fail_unlock:
    return -EINVAL;
}

struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
{
    struct inode *inode = new_inode(sb);

    if (inode == NULL)
        return NULL;

    inode->i_mode = mode;
    if (sb->s_root) {
        inode->i_uid = sb->s_root->d_inode->i_uid;
        inode->i_gid = sb->s_root->d_inode->i_gid;
    }
    inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
    inode->i_ino = get_next_ino();

    if (S_ISDIR(mode)) {
        set_nlink(inode, 2);
        inode->i_op = &autofs4_dir_inode_operations;
        inode->i_fop = &autofs4_dir_operations;
    } else if (S_ISLNK(mode)) {
        inode->i_op = &autofs4_symlink_inode_operations;
    }

    return inode;
}