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->dentry = NULL;
  49                 ino->size = 0;
  50                 INIT_LIST_HEAD(&ino->active);
  51                 ino->active_count = 0;
  52                 INIT_LIST_HEAD(&ino->expiring);
  53                 atomic_set(&ino->count, 0);
  54         }
  55
  56         ino->uid = 0;
  57         ino->gid = 0;
  58         ino->mode = mode;
  59         ino->last_used = jiffies;
  60
  61         ino->sbi = sbi;
  62
  63         if (reinit && ino->free)
  64                 (ino->free)(ino);
  65
  66         memset(&ino->u, 0, sizeof(ino->u));
  67
  68         ino->free = NULL;
  69
  70         if (S_ISLNK(mode))
  71                 ino->free = ino_lnkfree;
  72
  73         return ino;
  74 }
  75
  76 void autofs4_free_ino(struct autofs_info *ino)
  77 {
  78         if (ino->dentry) {
  79                 ino->dentry->d_fsdata = NULL;
  80                 ino->dentry = NULL;
  81         }
  82         if (ino->free)
  83                 (ino->free)(ino);
  84         kfree(ino);
  85 }
  86
  87 void autofs4_kill_sb(struct super_block *sb)
  88 {
  89         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  90
  91         /*
  92          * In the event of a failure in get_sb_nodev the superblock
  93          * info is not present so nothing else has been setup, so
  94          * just call kill_anon_super when we are called from
  95          * deactivate_super.
  96          */
  97         if (!sbi)
  98                 goto out_kill_sb;
  99
 100         /* Free wait queues, close pipe */
 101         autofs4_catatonic_mode(sbi);
 102
 103         sb->s_fs_info = NULL;
 104         kfree(sbi);
 105
 106 out_kill_sb:
 107         DPRINTK("shutting down");
 108         kill_litter_super(sb);
 109 }
 110
 111 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 112 {
 113         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 114         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
 115
 116         if (!sbi)
 117                 return 0;
 118
 119         seq_printf(m, ",fd=%d", sbi->pipefd);
 120         if (root_inode->i_uid != 0)
 121                 seq_printf(m, ",uid=%u", root_inode->i_uid);
 122         if (root_inode->i_gid != 0)
 123                 seq_printf(m, ",gid=%u", root_inode->i_gid);
 124         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 125         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 126         seq_printf(m, ",minproto=%d", sbi->min_proto);
 127         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 128
 129         if (autofs_type_offset(sbi->type))
 130                 seq_printf(m, ",offset");
 131         else if (autofs_type_direct(sbi->type))
 132                 seq_printf(m, ",direct");
 133         else
 134                 seq_printf(m, ",indirect");
 135
 136         return 0;
 137 }
 138
 139 static const struct super_operations autofs4_sops = {
 140         .statfs         = simple_statfs,
 141         .show_options   = autofs4_show_options,
 142 };
 143
 144 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 145         Opt_indirect, Opt_direct, Opt_offset};
 146
 147 static const match_table_t tokens = {
 148         {Opt_fd, "fd=%u"},
 149         {Opt_uid, "uid=%u"},
 150         {Opt_gid, "gid=%u"},
 151         {Opt_pgrp, "pgrp=%u"},
 152         {Opt_minproto, "minproto=%u"},
 153         {Opt_maxproto, "maxproto=%u"},
 154         {Opt_indirect, "indirect"},
 155         {Opt_direct, "direct"},
 156         {Opt_offset, "offset"},
 157         {Opt_err, NULL}
 158 };
 159
 160 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 161                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 162 {
 163         char *p;
 164         substring_t args[MAX_OPT_ARGS];
 165         int option;
 166
 167         *uid = current_uid();
 168         *gid = current_gid();
 169         *pgrp = task_pgrp_nr(current);
 170
 171         *minproto = AUTOFS_MIN_PROTO_VERSION;
 172         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 173
 174         *pipefd = -1;
 175
 176         if (!options)
 177                 return 1;
 178
 179         while ((p = strsep(&options, ",")) != NULL) {
 180                 int token;
 181                 if (!*p)
 182                         continue;
 183
 184                 token = match_token(p, tokens, args);
 185                 switch (token) {
 186                 case Opt_fd:
 187                         if (match_int(args, pipefd))
 188                                 return 1;
 189                         break;
 190                 case Opt_uid:
 191                         if (match_int(args, &option))
 192                                 return 1;
 193                         *uid = option;
 194                         break;
 195                 case Opt_gid:
 196                         if (match_int(args, &option))
 197                                 return 1;
 198                         *gid = option;
 199                         break;
 200                 case Opt_pgrp:
 201                         if (match_int(args, &option))
 202                                 return 1;
 203                         *pgrp = option;
 204                         break;
 205                 case Opt_minproto:
 206                         if (match_int(args, &option))
 207                                 return 1;
 208                         *minproto = option;
 209                         break;
 210                 case Opt_maxproto:
 211                         if (match_int(args, &option))
 212                                 return 1;
 213                         *maxproto = option;
 214                         break;
 215                 case Opt_indirect:
 216                         set_autofs_type_indirect(type);
 217                         break;
 218                 case Opt_direct:
 219                         set_autofs_type_direct(type);
 220                         break;
 221                 case Opt_offset:
 222                         set_autofs_type_offset(type);
 223                         break;
 224                 default:
 225                         return 1;
 226                 }
 227         }
 228         return (*pipefd < 0);
 229 }
 230
 231 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 232 {
 233         struct autofs_info *ino;
 234
 235         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 236         if (!ino)
 237                 return NULL;
 238
 239         return ino;
 240 }
 241
 242 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 243 {
 244         struct inode * root_inode;
 245         struct dentry * root;
 246         struct file * pipe;
 247         int pipefd;
 248         struct autofs_sb_info *sbi;
 249         struct autofs_info *ino;
 250
 251         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 252         if (!sbi)
 253                 goto fail_unlock;
 254         DPRINTK("starting up, sbi = %p",sbi);
 255
 256         s->s_fs_info = sbi;
 257         sbi->magic = AUTOFS_SBI_MAGIC;
 258         sbi->pipefd = -1;
 259         sbi->pipe = NULL;
 260         sbi->catatonic = 1;
 261         sbi->exp_timeout = 0;
 262         sbi->oz_pgrp = task_pgrp_nr(current);
 263         sbi->sb = s;
 264         sbi->version = 0;
 265         sbi->sub_version = 0;
 266         set_autofs_type_indirect(&sbi->type);
 267         sbi->min_proto = 0;
 268         sbi->max_proto = 0;
 269         mutex_init(&sbi->wq_mutex);
 270         spin_lock_init(&sbi->fs_lock);
 271         sbi->queues = NULL;
 272         spin_lock_init(&sbi->lookup_lock);
 273         INIT_LIST_HEAD(&sbi->active_list);
 274         INIT_LIST_HEAD(&sbi->expiring_list);
 275         s->s_blocksize = 1024;
 276         s->s_blocksize_bits = 10;
 277         s->s_magic = AUTOFS_SUPER_MAGIC;
 278         s->s_op = &autofs4_sops;
 279         s->s_d_op = &autofs4_dentry_operations;
 280         s->s_time_gran = 1;
 281
 282         /*
 283          * Get the root inode and dentry, but defer checking for errors.
 284          */
 285         ino = autofs4_mkroot(sbi);
 286         if (!ino)
 287                 goto fail_free;
 288         root_inode = autofs4_get_inode(s, ino);
 289         if (!root_inode)
 290                 goto fail_ino;
 291
 292         root = d_alloc_root(root_inode);
 293         if (!root)
 294                 goto fail_iput;
 295         pipe = NULL;
 296
 297         root->d_fsdata = ino;
 298
 299         /* Can this call block? */
 300         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 301                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 302                                 &sbi->max_proto)) {
 303                 printk("autofs: called with bogus options\n");
 304                 goto fail_dput;
 305         }
 306
 307         if (autofs_type_trigger(sbi->type))
 308                 __managed_dentry_set_managed(root);
 309
 310         root_inode->i_fop = &autofs4_root_operations;
 311         root_inode->i_op = &autofs4_dir_inode_operations;
 312
 313         /* Couldn't this be tested earlier? */
 314         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 315             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 316                 printk("autofs: kernel does not match daemon version "
 317                        "daemon (%d, %d) kernel (%d, %d)\n",
 318                         sbi->min_proto, sbi->max_proto,
 319                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 320                 goto fail_dput;
 321         }
 322
 323         /* Establish highest kernel protocol version */
 324         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 325                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 326         else
 327                 sbi->version = sbi->max_proto;
 328         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 329
 330         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 331         pipe = fget(pipefd);
 332
 333         if (!pipe) {
 334                 printk("autofs: could not open pipe file descriptor\n");
 335                 goto fail_dput;
 336         }
 337         if (!pipe->f_op || !pipe->f_op->write)
 338                 goto fail_fput;
 339         sbi->pipe = pipe;
 340         sbi->pipefd = pipefd;
 341         sbi->catatonic = 0;
 342
 343         /*
 344          * Success! Install the root dentry now to indicate completion.
 345          */
 346         s->s_root = root;
 347         return 0;
 348
 349         /*
 350          * Failure ... clean up.
 351          */
 352 fail_fput:
 353         printk("autofs: pipe file descriptor does not contain proper ops\n");
 354         fput(pipe);
 355         /* fall through */
 356 fail_dput:
 357         dput(root);
 358         goto fail_free;
 359 fail_iput:
 360         printk("autofs: get root dentry failed\n");
 361         iput(root_inode);
 362 fail_ino:
 363         kfree(ino);
 364 fail_free:
 365         kfree(sbi);
 366         s->s_fs_info = NULL;
 367 fail_unlock:
 368         return -EINVAL;
 369 }
 370
 371 struct inode *autofs4_get_inode(struct super_block *sb,
 372                                 struct autofs_info *inf)
 373 {
 374         struct inode *inode = new_inode(sb);
 375
 376         if (inode == NULL)
 377                 return NULL;
 378
 379         inode->i_mode = inf->mode;
 380         if (sb->s_root) {
 381                 inode->i_uid = sb->s_root->d_inode->i_uid;
 382                 inode->i_gid = sb->s_root->d_inode->i_gid;
 383         }
 384         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 385         inode->i_ino = get_next_ino();
 386
 387         if (S_ISDIR(inf->mode)) {
 388                 inode->i_nlink = 2;
 389                 inode->i_op = &autofs4_dir_inode_operations;
 390                 inode->i_fop = &autofs4_dir_operations;
 391         } else if (S_ISLNK(inf->mode)) {
 392                 inode->i_size = inf->size;
 393                 inode->i_op = &autofs4_symlink_inode_operations;
 394         }
 395
 396         return inode;
 397 }