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 <[email protected]>
   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 struct 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
  37 void autofs4_clean_ino(struct autofs_info *ino)
  38 {
  39         ino->uid = 0;
  40         ino->gid = 0;
  41         ino->last_used = jiffies;
  42 }
  43
  44 void autofs4_free_ino(struct autofs_info *ino)
  45 {
  46         kfree(ino);
  47 }
  48
  49 void 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
  68 out_kill_sb:
  69         DPRINTK("shutting down");
  70         kill_litter_super(sb);
  71 }
  72
  73 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
  74 {
  75         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
  76         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
  77
  78         if (!sbi)
  79                 return 0;
  80
  81         seq_printf(m, ",fd=%d", sbi->pipefd);
  82         if (root_inode->i_uid != 0)
  83                 seq_printf(m, ",uid=%u", root_inode->i_uid);
  84         if (root_inode->i_gid != 0)
  85                 seq_printf(m, ",gid=%u", root_inode->i_gid);
  86         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
  87         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  88         seq_printf(m, ",minproto=%d", sbi->min_proto);
  89         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  90
  91         if (autofs_type_offset(sbi->type))
  92                 seq_printf(m, ",offset");
  93         else if (autofs_type_direct(sbi->type))
  94                 seq_printf(m, ",direct");
  95         else
  96                 seq_printf(m, ",indirect");
  97
  98         return 0;
  99 }
 100
 101 static void autofs4_evict_inode(struct inode *inode)
 102 {
 103         end_writeback(inode);
 104         kfree(inode->i_private);
 105 }
 106
 107 static const struct super_operations autofs4_sops = {
 108         .statfs         = simple_statfs,
 109         .show_options   = autofs4_show_options,
 110         .evict_inode    = autofs4_evict_inode,
 111 };
 112
 113 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 114         Opt_indirect, Opt_direct, Opt_offset};
 115
 116 static const match_table_t tokens = {
 117         {Opt_fd, "fd=%u"},
 118         {Opt_uid, "uid=%u"},
 119         {Opt_gid, "gid=%u"},
 120         {Opt_pgrp, "pgrp=%u"},
 121         {Opt_minproto, "minproto=%u"},
 122         {Opt_maxproto, "maxproto=%u"},
 123         {Opt_indirect, "indirect"},
 124         {Opt_direct, "direct"},
 125         {Opt_offset, "offset"},
 126         {Opt_err, NULL}
 127 };
 128
 129 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 130                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 131 {
 132         char *p;
 133         substring_t args[MAX_OPT_ARGS];
 134         int option;
 135
 136         *uid = current_uid();
 137         *gid = current_gid();
 138         *pgrp = task_pgrp_nr(current);
 139
 140         *minproto = AUTOFS_MIN_PROTO_VERSION;
 141         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 142
 143         *pipefd = -1;
 144
 145         if (!options)
 146                 return 1;
 147
 148         while ((p = strsep(&options, ",")) != NULL) {
 149                 int token;
 150                 if (!*p)
 151                         continue;
 152
 153                 token = match_token(p, tokens, args);
 154                 switch (token) {
 155                 case Opt_fd:
 156                         if (match_int(args, pipefd))
 157                                 return 1;
 158                         break;
 159                 case Opt_uid:
 160                         if (match_int(args, &option))
 161                                 return 1;
 162                         *uid = option;
 163                         break;
 164                 case Opt_gid:
 165                         if (match_int(args, &option))
 166                                 return 1;
 167                         *gid = option;
 168                         break;
 169                 case Opt_pgrp:
 170                         if (match_int(args, &option))
 171                                 return 1;
 172                         *pgrp = option;
 173                         break;
 174                 case Opt_minproto:
 175                         if (match_int(args, &option))
 176                                 return 1;
 177                         *minproto = option;
 178                         break;
 179                 case Opt_maxproto:
 180                         if (match_int(args, &option))
 181                                 return 1;
 182                         *maxproto = option;
 183                         break;
 184                 case Opt_indirect:
 185                         set_autofs_type_indirect(type);
 186                         break;
 187                 case Opt_direct:
 188                         set_autofs_type_direct(type);
 189                         break;
 190                 case Opt_offset:
 191                         set_autofs_type_offset(type);
 192                         break;
 193                 default:
 194                         return 1;
 195                 }
 196         }
 197         return (*pipefd < 0);
 198 }
 199
 200 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 201 {
 202         struct inode * root_inode;
 203         struct dentry * root;
 204         struct file * pipe;
 205         int pipefd;
 206         struct autofs_sb_info *sbi;
 207         struct autofs_info *ino;
 208
 209         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 210         if (!sbi)
 211                 goto fail_unlock;
 212         DPRINTK("starting up, sbi = %p",sbi);
 213
 214         s->s_fs_info = sbi;
 215         sbi->magic = AUTOFS_SBI_MAGIC;
 216         sbi->pipefd = -1;
 217         sbi->pipe = NULL;
 218         sbi->catatonic = 1;
 219         sbi->exp_timeout = 0;
 220         sbi->oz_pgrp = task_pgrp_nr(current);
 221         sbi->sb = s;
 222         sbi->version = 0;
 223         sbi->sub_version = 0;
 224         set_autofs_type_indirect(&sbi->type);
 225         sbi->min_proto = 0;
 226         sbi->max_proto = 0;
 227         mutex_init(&sbi->wq_mutex);
 228         spin_lock_init(&sbi->fs_lock);
 229         sbi->queues = NULL;
 230         spin_lock_init(&sbi->lookup_lock);
 231         INIT_LIST_HEAD(&sbi->active_list);
 232         INIT_LIST_HEAD(&sbi->expiring_list);
 233         s->s_blocksize = 1024;
 234         s->s_blocksize_bits = 10;
 235         s->s_magic = AUTOFS_SUPER_MAGIC;
 236         s->s_op = &autofs4_sops;
 237         s->s_d_op = &autofs4_dentry_operations;
 238         s->s_time_gran = 1;
 239
 240         /*
 241          * Get the root inode and dentry, but defer checking for errors.
 242          */
 243         ino = autofs4_new_ino(sbi);
 244         if (!ino)
 245                 goto fail_free;
 246         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
 247         if (!root_inode)
 248                 goto fail_ino;
 249
 250         root = d_alloc_root(root_inode);
 251         if (!root)
 252                 goto fail_iput;
 253         pipe = NULL;
 254
 255         root->d_fsdata = ino;
 256
 257         /* Can this call block? */
 258         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 259                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 260                                 &sbi->max_proto)) {
 261                 printk("autofs: called with bogus options\n");
 262                 goto fail_dput;
 263         }
 264
 265         if (autofs_type_trigger(sbi->type))
 266                 __managed_dentry_set_managed(root);
 267
 268         root_inode->i_fop = &autofs4_root_operations;
 269         root_inode->i_op = &autofs4_dir_inode_operations;
 270
 271         /* Couldn't this be tested earlier? */
 272         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 273             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 274                 printk("autofs: kernel does not match daemon version "
 275                        "daemon (%d, %d) kernel (%d, %d)\n",
 276                         sbi->min_proto, sbi->max_proto,
 277                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 278                 goto fail_dput;
 279         }
 280
 281         /* Establish highest kernel protocol version */
 282         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 283                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 284         else
 285                 sbi->version = sbi->max_proto;
 286         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 287
 288         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 289         pipe = fget(pipefd);
 290
 291         if (!pipe) {
 292                 printk("autofs: could not open pipe file descriptor\n");
 293                 goto fail_dput;
 294         }
 295         if (!pipe->f_op || !pipe->f_op->write)
 296                 goto fail_fput;
 297         sbi->pipe = pipe;
 298         sbi->pipefd = pipefd;
 299         sbi->catatonic = 0;
 300
 301         /*
 302          * Success! Install the root dentry now to indicate completion.
 303          */
 304         s->s_root = root;
 305         return 0;
 306
 307         /*
 308          * Failure ... clean up.
 309          */
 310 fail_fput:
 311         printk("autofs: pipe file descriptor does not contain proper ops\n");
 312         fput(pipe);
 313         /* fall through */
 314 fail_dput:
 315         dput(root);
 316         goto fail_free;
 317 fail_iput:
 318         printk("autofs: get root dentry failed\n");
 319         iput(root_inode);
 320 fail_ino:
 321         kfree(ino);
 322 fail_free:
 323         kfree(sbi);
 324         s->s_fs_info = NULL;
 325 fail_unlock:
 326         return -EINVAL;
 327 }
 328
 329 struct inode *autofs4_get_inode(struct super_block *sb, mode_t mode)
 330 {
 331         struct inode *inode = new_inode(sb);
 332
 333         if (inode == NULL)
 334                 return NULL;
 335
 336         inode->i_mode = mode;
 337         if (sb->s_root) {
 338                 inode->i_uid = sb->s_root->d_inode->i_uid;
 339                 inode->i_gid = sb->s_root->d_inode->i_gid;
 340         }
 341         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 342         inode->i_ino = get_next_ino();
 343
 344         if (S_ISDIR(mode)) {
 345                 inode->i_nlink = 2;
 346                 inode->i_op = &autofs4_dir_inode_operations;
 347                 inode->i_fop = &autofs4_dir_operations;
 348         } else if (S_ISLNK(mode)) {
 349                 inode->i_op = &autofs4_symlink_inode_operations;
 350         }
 351
 352         return inode;
 353 }