fs/autofs4/inode.c

   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
  25 static void ino_lnkfree(struct autofs_info *ino)
  26 {
  27         if (ino->u.symlink) {
  28                 kfree(ino->u.symlink);
  29                 ino->u.symlink = NULL;
  30         }
  31 }
  32
  33 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  34                                      struct autofs_sb_info *sbi, mode_t mode)
  35 {
  36         int reinit = 1;
  37
  38         if (ino == NULL) {
  39                 reinit = 0;
  40                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  41         }
  42
  43         if (ino == NULL)
  44                 return NULL;
  45
  46         if (!reinit) {
  47                 ino->flags = 0;
  48                 ino->inode = NULL;
  49                 ino->dentry = NULL;
  50                 ino->size = 0;
  51                 INIT_LIST_HEAD(&ino->active);
  52                 ino->active_count = 0;
  53                 INIT_LIST_HEAD(&ino->expiring);
  54                 atomic_set(&ino->count, 0);
  55         }
  56
  57         ino->uid = 0;
  58         ino->gid = 0;
  59         ino->mode = mode;
  60         ino->last_used = jiffies;
  61
  62         ino->sbi = sbi;
  63
  64         if (reinit && ino->free)
  65                 (ino->free)(ino);
  66
  67         memset(&ino->u, 0, sizeof(ino->u));
  68
  69         ino->free = NULL;
  70
  71         if (S_ISLNK(mode))
  72                 ino->free = ino_lnkfree;
  73
  74         return ino;
  75 }
  76
  77 void autofs4_free_ino(struct autofs_info *ino)
  78 {
  79         struct autofs_info *p_ino;
  80
  81         if (ino->dentry) {
  82                 ino->dentry->d_fsdata = NULL;
  83                 if (ino->dentry->d_inode) {
  84                         struct dentry *parent = ino->dentry->d_parent;
  85                         if (atomic_dec_and_test(&ino->count)) {
  86                                 p_ino = autofs4_dentry_ino(parent);
  87                                 if (p_ino && parent != ino->dentry)
  88                                         atomic_dec(&p_ino->count);
  89                         }
  90                         dput(ino->dentry);
  91                 }
  92                 ino->dentry = NULL;
  93         }
  94         if (ino->free)
  95                 (ino->free)(ino);
  96         kfree(ino);
  97 }
  98
  99 void autofs4_kill_sb(struct super_block *sb)
 100 {
 101         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 102
 103         /*
 104          * In the event of a failure in get_sb_nodev the superblock
 105          * info is not present so nothing else has been setup, so
 106          * just call kill_anon_super when we are called from
 107          * deactivate_super.
 108          */
 109         if (!sbi)
 110                 goto out_kill_sb;
 111
 112         /* Free wait queues, close pipe */
 113         autofs4_catatonic_mode(sbi);
 114
 115         sb->s_fs_info = NULL;
 116         kfree(sbi);
 117
 118 out_kill_sb:
 119         DPRINTK("shutting down");
 120         kill_litter_super(sb);
 121 }
 122
 123 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 124 {
 125         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 126         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
 127
 128         if (!sbi)
 129                 return 0;
 130
 131         seq_printf(m, ",fd=%d", sbi->pipefd);
 132         if (root_inode->i_uid != 0)
 133                 seq_printf(m, ",uid=%u", root_inode->i_uid);
 134         if (root_inode->i_gid != 0)
 135                 seq_printf(m, ",gid=%u", root_inode->i_gid);
 136         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 137         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 138         seq_printf(m, ",minproto=%d", sbi->min_proto);
 139         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 140
 141         if (autofs_type_offset(sbi->type))
 142                 seq_printf(m, ",offset");
 143         else if (autofs_type_direct(sbi->type))
 144                 seq_printf(m, ",direct");
 145         else
 146                 seq_printf(m, ",indirect");
 147
 148         return 0;
 149 }
 150
 151 static const struct super_operations autofs4_sops = {
 152         .statfs         = simple_statfs,
 153         .show_options   = autofs4_show_options,
 154 };
 155
 156 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 157         Opt_indirect, Opt_direct, Opt_offset};
 158
 159 static const match_table_t tokens = {
 160         {Opt_fd, "fd=%u"},
 161         {Opt_uid, "uid=%u"},
 162         {Opt_gid, "gid=%u"},
 163         {Opt_pgrp, "pgrp=%u"},
 164         {Opt_minproto, "minproto=%u"},
 165         {Opt_maxproto, "maxproto=%u"},
 166         {Opt_indirect, "indirect"},
 167         {Opt_direct, "direct"},
 168         {Opt_offset, "offset"},
 169         {Opt_err, NULL}
 170 };
 171
 172 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 173                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 174 {
 175         char *p;
 176         substring_t args[MAX_OPT_ARGS];
 177         int option;
 178
 179         *uid = current_uid();
 180         *gid = current_gid();
 181         *pgrp = task_pgrp_nr(current);
 182
 183         *minproto = AUTOFS_MIN_PROTO_VERSION;
 184         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 185
 186         *pipefd = -1;
 187
 188         if (!options)
 189                 return 1;
 190
 191         while ((p = strsep(&options, ",")) != NULL) {
 192                 int token;
 193                 if (!*p)
 194                         continue;
 195
 196                 token = match_token(p, tokens, args);
 197                 switch (token) {
 198                 case Opt_fd:
 199                         if (match_int(args, pipefd))
 200                                 return 1;
 201                         break;
 202                 case Opt_uid:
 203                         if (match_int(args, &option))
 204                                 return 1;
 205                         *uid = option;
 206                         break;
 207                 case Opt_gid:
 208                         if (match_int(args, &option))
 209                                 return 1;
 210                         *gid = option;
 211                         break;
 212                 case Opt_pgrp:
 213                         if (match_int(args, &option))
 214                                 return 1;
 215                         *pgrp = option;
 216                         break;
 217                 case Opt_minproto:
 218                         if (match_int(args, &option))
 219                                 return 1;
 220                         *minproto = option;
 221                         break;
 222                 case Opt_maxproto:
 223                         if (match_int(args, &option))
 224                                 return 1;
 225                         *maxproto = option;
 226                         break;
 227                 case Opt_indirect:
 228                         set_autofs_type_indirect(type);
 229                         break;
 230                 case Opt_direct:
 231                         set_autofs_type_direct(type);
 232                         break;
 233                 case Opt_offset:
 234                         set_autofs_type_offset(type);
 235                         break;
 236                 default:
 237                         return 1;
 238                 }
 239         }
 240         return (*pipefd < 0);
 241 }
 242
 243 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 244 {
 245         struct autofs_info *ino;
 246
 247         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 248         if (!ino)
 249                 return NULL;
 250
 251         return ino;
 252 }
 253
 254 static const struct dentry_operations autofs4_sb_dentry_operations = {
 255         .d_release      = autofs4_dentry_release,
 256 };
 257
 258 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 259 {
 260         struct inode * root_inode;
 261         struct dentry * root;
 262         struct file * pipe;
 263         int pipefd;
 264         struct autofs_sb_info *sbi;
 265         struct autofs_info *ino;
 266
 267         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 268         if (!sbi)
 269                 goto fail_unlock;
 270         DPRINTK("starting up, sbi = %p",sbi);
 271
 272         s->s_fs_info = sbi;
 273         sbi->magic = AUTOFS_SBI_MAGIC;
 274         sbi->pipefd = -1;
 275         sbi->pipe = NULL;
 276         sbi->catatonic = 1;
 277         sbi->exp_timeout = 0;
 278         sbi->oz_pgrp = task_pgrp_nr(current);
 279         sbi->sb = s;
 280         sbi->version = 0;
 281         sbi->sub_version = 0;
 282         set_autofs_type_indirect(&sbi->type);
 283         sbi->min_proto = 0;
 284         sbi->max_proto = 0;
 285         mutex_init(&sbi->wq_mutex);
 286         spin_lock_init(&sbi->fs_lock);
 287         sbi->queues = NULL;
 288         spin_lock_init(&sbi->lookup_lock);
 289         INIT_LIST_HEAD(&sbi->active_list);
 290         INIT_LIST_HEAD(&sbi->expiring_list);
 291         s->s_blocksize = 1024;
 292         s->s_blocksize_bits = 10;
 293         s->s_magic = AUTOFS_SUPER_MAGIC;
 294         s->s_op = &autofs4_sops;
 295         s->s_time_gran = 1;
 296
 297         /*
 298          * Get the root inode and dentry, but defer checking for errors.
 299          */
 300         ino = autofs4_mkroot(sbi);
 301         if (!ino)
 302                 goto fail_free;
 303         root_inode = autofs4_get_inode(s, ino);
 304         if (!root_inode)
 305                 goto fail_ino;
 306
 307         root = d_alloc_root(root_inode);
 308         if (!root)
 309                 goto fail_iput;
 310         pipe = NULL;
 311
 312         root->d_op = &autofs4_sb_dentry_operations;
 313         root->d_fsdata = ino;
 314
 315         /* Can this call block? */
 316         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 317                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 318                                 &sbi->max_proto)) {
 319                 printk("autofs: called with bogus options\n");
 320                 goto fail_dput;
 321         }
 322
 323         root_inode->i_fop = &autofs4_root_operations;
 324         root_inode->i_op = autofs_type_trigger(sbi->type) ?
 325                         &autofs4_direct_root_inode_operations :
 326                         &autofs4_indirect_root_inode_operations;
 327
 328         /* Couldn't this be tested earlier? */
 329         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 330             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 331                 printk("autofs: kernel does not match daemon version "
 332                        "daemon (%d, %d) kernel (%d, %d)\n",
 333                         sbi->min_proto, sbi->max_proto,
 334                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 335                 goto fail_dput;
 336         }
 337
 338         /* Establish highest kernel protocol version */
 339         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 340                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 341         else
 342                 sbi->version = sbi->max_proto;
 343         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 344
 345         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 346         pipe = fget(pipefd);
 347
 348         if (!pipe) {
 349                 printk("autofs: could not open pipe file descriptor\n");
 350                 goto fail_dput;
 351         }
 352         if (!pipe->f_op || !pipe->f_op->write)
 353                 goto fail_fput;
 354         sbi->pipe = pipe;
 355         sbi->pipefd = pipefd;
 356         sbi->catatonic = 0;
 357
 358         /*
 359          * Success! Install the root dentry now to indicate completion.
 360          */
 361         s->s_root = root;
 362         return 0;
 363
 364         /*
 365          * Failure ... clean up.
 366          */
 367 fail_fput:
 368         printk("autofs: pipe file descriptor does not contain proper ops\n");
 369         fput(pipe);
 370         /* fall through */
 371 fail_dput:
 372         dput(root);
 373         goto fail_free;
 374 fail_iput:
 375         printk("autofs: get root dentry failed\n");
 376         iput(root_inode);
 377 fail_ino:
 378         kfree(ino);
 379 fail_free:
 380         kfree(sbi);
 381         s->s_fs_info = NULL;
 382 fail_unlock:
 383         return -EINVAL;
 384 }
 385
 386 struct inode *autofs4_get_inode(struct super_block *sb,
 387                                 struct autofs_info *inf)
 388 {
 389         struct inode *inode = new_inode(sb);
 390
 391         if (inode == NULL)
 392                 return NULL;
 393
 394         inf->inode = inode;
 395         inode->i_mode = inf->mode;
 396         if (sb->s_root) {
 397                 inode->i_uid = sb->s_root->d_inode->i_uid;
 398                 inode->i_gid = sb->s_root->d_inode->i_gid;
 399         }
 400         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 401
 402         if (S_ISDIR(inf->mode)) {
 403                 inode->i_nlink = 2;
 404                 inode->i_op = &autofs4_dir_inode_operations;
 405                 inode->i_fop = &autofs4_dir_operations;
 406         } else if (S_ISLNK(inf->mode)) {
 407                 inode->i_size = inf->size;
 408                 inode->i_op = &autofs4_symlink_inode_operations;
 409         }
 410
 411         return inode;
 412 }