linux/fs/autofs4/inode.c
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   1/* -*- c -*- --------------------------------------------------------------- *
   2 *
   3 * linux/fs/autofs/inode.c
   4 *
   5 *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   6 *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
   7 *
   8 * This file is part of the Linux kernel and is made available under
   9 * the terms of the GNU General Public License, version 2, or at your
  10 * option, any later version, incorporated herein by reference.
  11 *
  12 * ------------------------------------------------------------------------- */
  13
  14#include <linux/kernel.h>
  15#include <linux/slab.h>
  16#include <linux/file.h>
  17#include <linux/seq_file.h>
  18#include <linux/pagemap.h>
  19#include <linux/parser.h>
  20#include <linux/bitops.h>
  21#include <linux/magic.h>
  22#include "autofs_i.h"
  23#include <linux/module.h>
  24
  25struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
  26{
  27        struct autofs_info *ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  28        if (ino) {
  29                INIT_LIST_HEAD(&ino->active);
  30                INIT_LIST_HEAD(&ino->expiring);
  31                ino->last_used = jiffies;
  32                ino->sbi = sbi;
  33        }
  34        return ino;
  35}
  36
  37void autofs4_clean_ino(struct autofs_info *ino)
  38{
  39        ino->uid = GLOBAL_ROOT_UID;
  40        ino->gid = GLOBAL_ROOT_GID;
  41        ino->last_used = jiffies;
  42}
  43
  44void autofs4_free_ino(struct autofs_info *ino)
  45{
  46        kfree(ino);
  47}
  48
  49void autofs4_kill_sb(struct super_block *sb)
  50{
  51        struct autofs_sb_info *sbi = autofs4_sbi(sb);
  52
  53        /*
  54         * In the event of a failure in get_sb_nodev the superblock
  55         * info is not present so nothing else has been setup, so
  56         * just call kill_anon_super when we are called from
  57         * deactivate_super.
  58         */
  59        if (!sbi)
  60                goto out_kill_sb;
  61
  62        /* Free wait queues, close pipe */
  63        autofs4_catatonic_mode(sbi);
  64
  65        sb->s_fs_info = NULL;
  66        kfree(sbi);
  67
  68out_kill_sb:
  69        DPRINTK("shutting down");
  70        kill_litter_super(sb);
  71}
  72
  73static int autofs4_show_options(struct seq_file *m, struct dentry *root)
  74{
  75        struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
  76        struct inode *root_inode = root->d_sb->s_root->d_inode;
  77
  78        if (!sbi)
  79                return 0;
  80
  81        seq_printf(m, ",fd=%d", sbi->pipefd);
  82        if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  83                seq_printf(m, ",uid=%u",
  84                        from_kuid_munged(&init_user_ns, root_inode->i_uid));
  85        if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  86                seq_printf(m, ",gid=%u",
  87                        from_kgid_munged(&init_user_ns, root_inode->i_gid));
  88        seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
  89        seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  90        seq_printf(m, ",minproto=%d", sbi->min_proto);
  91        seq_printf(m, ",maxproto=%d", sbi->max_proto);
  92
  93        if (autofs_type_offset(sbi->type))
  94                seq_printf(m, ",offset");
  95        else if (autofs_type_direct(sbi->type))
  96                seq_printf(m, ",direct");
  97        else
  98                seq_printf(m, ",indirect");
  99
 100        return 0;
 101}
 102
 103static void autofs4_evict_inode(struct inode *inode)
 104{
 105        clear_inode(inode);
 106        kfree(inode->i_private);
 107}
 108
 109static const struct super_operations autofs4_sops = {
 110        .statfs         = simple_statfs,
 111        .show_options   = autofs4_show_options,
 112        .evict_inode    = autofs4_evict_inode,
 113};
 114
 115enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 116        Opt_indirect, Opt_direct, Opt_offset};
 117
 118static const match_table_t tokens = {
 119        {Opt_fd, "fd=%u"},
 120        {Opt_uid, "uid=%u"},
 121        {Opt_gid, "gid=%u"},
 122        {Opt_pgrp, "pgrp=%u"},
 123        {Opt_minproto, "minproto=%u"},
 124        {Opt_maxproto, "maxproto=%u"},
 125        {Opt_indirect, "indirect"},
 126        {Opt_direct, "direct"},
 127        {Opt_offset, "offset"},
 128        {Opt_err, NULL}
 129};
 130
 131static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
 132                pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 133{
 134        char *p;
 135        substring_t args[MAX_OPT_ARGS];
 136        int option;
 137
 138        *uid = current_uid();
 139        *gid = current_gid();
 140        *pgrp = task_pgrp_nr(current);
 141
 142        *minproto = AUTOFS_MIN_PROTO_VERSION;
 143        *maxproto = AUTOFS_MAX_PROTO_VERSION;
 144
 145        *pipefd = -1;
 146
 147        if (!options)
 148                return 1;
 149
 150        while ((p = strsep(&options, ",")) != NULL) {
 151                int token;
 152                if (!*p)
 153                        continue;
 154
 155                token = match_token(p, tokens, args);
 156                switch (token) {
 157                case Opt_fd:
 158                        if (match_int(args, pipefd))
 159                                return 1;
 160                        break;
 161                case Opt_uid:
 162                        if (match_int(args, &option))
 163                                return 1;
 164                        *uid = make_kuid(current_user_ns(), option);
 165                        if (!uid_valid(*uid))
 166                                return 1;
 167                        break;
 168                case Opt_gid:
 169                        if (match_int(args, &option))
 170                                return 1;
 171                        *gid = make_kgid(current_user_ns(), option);
 172                        if (!gid_valid(*gid))
 173                                return 1;
 174                        break;
 175                case Opt_pgrp:
 176                        if (match_int(args, &option))
 177                                return 1;
 178                        *pgrp = option;
 179                        break;
 180                case Opt_minproto:
 181                        if (match_int(args, &option))
 182                                return 1;
 183                        *minproto = option;
 184                        break;
 185                case Opt_maxproto:
 186                        if (match_int(args, &option))
 187                                return 1;
 188                        *maxproto = option;
 189                        break;
 190                case Opt_indirect:
 191                        set_autofs_type_indirect(type);
 192                        break;
 193                case Opt_direct:
 194                        set_autofs_type_direct(type);
 195                        break;
 196                case Opt_offset:
 197                        set_autofs_type_offset(type);
 198                        break;
 199                default:
 200                        return 1;
 201                }
 202        }
 203        return (*pipefd < 0);
 204}
 205
 206int autofs4_fill_super(struct super_block *s, void *data, int silent)
 207{
 208        struct inode * root_inode;
 209        struct dentry * root;
 210        struct file * pipe;
 211        int pipefd;
 212        struct autofs_sb_info *sbi;
 213        struct autofs_info *ino;
 214
 215        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 216        if (!sbi)
 217                goto fail_unlock;
 218        DPRINTK("starting up, sbi = %p",sbi);
 219
 220        s->s_fs_info = sbi;
 221        sbi->magic = AUTOFS_SBI_MAGIC;
 222        sbi->pipefd = -1;
 223        sbi->pipe = NULL;
 224        sbi->catatonic = 1;
 225        sbi->exp_timeout = 0;
 226        sbi->oz_pgrp = task_pgrp_nr(current);
 227        sbi->sb = s;
 228        sbi->version = 0;
 229        sbi->sub_version = 0;
 230        set_autofs_type_indirect(&sbi->type);
 231        sbi->min_proto = 0;
 232        sbi->max_proto = 0;
 233        mutex_init(&sbi->wq_mutex);
 234        mutex_init(&sbi->pipe_mutex);
 235        spin_lock_init(&sbi->fs_lock);
 236        sbi->queues = NULL;
 237        spin_lock_init(&sbi->lookup_lock);
 238        INIT_LIST_HEAD(&sbi->active_list);
 239        INIT_LIST_HEAD(&sbi->expiring_list);
 240        s->s_blocksize = 1024;
 241        s->s_blocksize_bits = 10;
 242        s->s_magic = AUTOFS_SUPER_MAGIC;
 243        s->s_op = &autofs4_sops;
 244        s->s_d_op = &autofs4_dentry_operations;
 245        s->s_time_gran = 1;
 246
 247        /*
 248         * Get the root inode and dentry, but defer checking for errors.
 249         */
 250        ino = autofs4_new_ino(sbi);
 251        if (!ino)
 252                goto fail_free;
 253        root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
 254        root = d_make_root(root_inode);
 255        if (!root)
 256                goto fail_ino;
 257        pipe = NULL;
 258
 259        root->d_fsdata = ino;
 260
 261        /* Can this call block? */
 262        if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 263                                &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 264                                &sbi->max_proto)) {
 265                printk("autofs: called with bogus options\n");
 266                goto fail_dput;
 267        }
 268
 269        if (autofs_type_trigger(sbi->type))
 270                __managed_dentry_set_managed(root);
 271
 272        root_inode->i_fop = &autofs4_root_operations;
 273        root_inode->i_op = &autofs4_dir_inode_operations;
 274
 275        /* Couldn't this be tested earlier? */
 276        if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 277            sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 278                printk("autofs: kernel does not match daemon version "
 279                       "daemon (%d, %d) kernel (%d, %d)\n",
 280                        sbi->min_proto, sbi->max_proto,
 281                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 282                goto fail_dput;
 283        }
 284
 285        /* Establish highest kernel protocol version */
 286        if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 287                sbi->version = AUTOFS_MAX_PROTO_VERSION;
 288        else
 289                sbi->version = sbi->max_proto;
 290        sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 291
 292        DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 293        pipe = fget(pipefd);
 294        
 295        if (!pipe) {
 296                printk("autofs: could not open pipe file descriptor\n");
 297                goto fail_dput;
 298        }
 299        if (autofs_prepare_pipe(pipe) < 0)
 300                goto fail_fput;
 301        sbi->pipe = pipe;
 302        sbi->pipefd = pipefd;
 303        sbi->catatonic = 0;
 304
 305        /*
 306         * Success! Install the root dentry now to indicate completion.
 307         */
 308        s->s_root = root;
 309        return 0;
 310        
 311        /*
 312         * Failure ... clean up.
 313         */
 314fail_fput:
 315        printk("autofs: pipe file descriptor does not contain proper ops\n");
 316        fput(pipe);
 317        /* fall through */
 318fail_dput:
 319        dput(root);
 320        goto fail_free;
 321fail_ino:
 322        kfree(ino);
 323fail_free:
 324        kfree(sbi);
 325        s->s_fs_info = NULL;
 326fail_unlock:
 327        return -EINVAL;
 328}
 329
 330struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
 331{
 332        struct inode *inode = new_inode(sb);
 333
 334        if (inode == NULL)
 335                return NULL;
 336
 337        inode->i_mode = mode;
 338        if (sb->s_root) {
 339                inode->i_uid = sb->s_root->d_inode->i_uid;
 340                inode->i_gid = sb->s_root->d_inode->i_gid;
 341        }
 342        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 343        inode->i_ino = get_next_ino();
 344
 345        if (S_ISDIR(mode)) {
 346                set_nlink(inode, 2);
 347                inode->i_op = &autofs4_dir_inode_operations;
 348                inode->i_fop = &autofs4_dir_operations;
 349        } else if (S_ISLNK(mode)) {
 350                inode->i_op = &autofs4_symlink_inode_operations;
 351        }
 352
 353        return inode;
 354}
 355
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