fs/autofs/inode.c

   1 /*
   2  * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   3  * Copyright 2005-2006 Ian Kent <raven@themaw.net>
   4  *
   5  * This file is part of the Linux kernel and is made available under
   6  * the terms of the GNU General Public License, version 2, or at your
   7  * option, any later version, incorporated herein by reference.
   8  */
   9
  10 #include <linux/seq_file.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/parser.h>
  13
  14 #include "autofs_i.h"
  15
  16 struct autofs_info *autofs_new_ino(struct autofs_sb_info *sbi)
  17 {
  18         struct autofs_info *ino;
  19
  20         ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  21         if (ino) {
  22                 INIT_LIST_HEAD(&ino->active);
  23                 INIT_LIST_HEAD(&ino->expiring);
  24                 ino->last_used = jiffies;
  25                 ino->sbi = sbi;
  26         }
  27         return ino;
  28 }
  29
  30 void autofs_clean_ino(struct autofs_info *ino)
  31 {
  32         ino->uid = GLOBAL_ROOT_UID;
  33         ino->gid = GLOBAL_ROOT_GID;
  34         ino->last_used = jiffies;
  35 }
  36
  37 void autofs_free_ino(struct autofs_info *ino)
  38 {
  39         kfree(ino);
  40 }
  41
  42 void autofs_kill_sb(struct super_block *sb)
  43 {
  44         struct autofs_sb_info *sbi = autofs_sbi(sb);
  45
  46         /*
  47          * In the event of a failure in get_sb_nodev the superblock
  48          * info is not present so nothing else has been setup, so
  49          * just call kill_anon_super when we are called from
  50          * deactivate_super.
  51          */
  52         if (sbi) {
  53                 /* Free wait queues, close pipe */
  54                 autofs_catatonic_mode(sbi);
  55                 put_pid(sbi->oz_pgrp);
  56         }
  57
  58         pr_debug("shutting down\n");
  59         kill_litter_super(sb);
  60         if (sbi)
  61                 kfree_rcu(sbi, rcu);
  62 }
  63
  64 static int autofs_show_options(struct seq_file *m, struct dentry *root)
  65 {
  66         struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
  67         struct inode *root_inode = d_inode(root->d_sb->s_root);
  68
  69         if (!sbi)
  70                 return 0;
  71
  72         seq_printf(m, ",fd=%d", sbi->pipefd);
  73         if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  74                 seq_printf(m, ",uid=%u",
  75                         from_kuid_munged(&init_user_ns, root_inode->i_uid));
  76         if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  77                 seq_printf(m, ",gid=%u",
  78                         from_kgid_munged(&init_user_ns, root_inode->i_gid));
  79         seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  80         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  81         seq_printf(m, ",minproto=%d", sbi->min_proto);
  82         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  83
  84         if (autofs_type_offset(sbi->type))
  85                 seq_printf(m, ",offset");
  86         else if (autofs_type_direct(sbi->type))
  87                 seq_printf(m, ",direct");
  88         else
  89                 seq_printf(m, ",indirect");
  90 #ifdef CONFIG_CHECKPOINT_RESTORE
  91         if (sbi->pipe)
  92                 seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
  93         else
  94                 seq_printf(m, ",pipe_ino=-1");
  95 #endif
  96         return 0;
  97 }
  98
  99 static void autofs_evict_inode(struct inode *inode)
 100 {
 101         clear_inode(inode);
 102         kfree(inode->i_private);
 103 }
 104
 105 static const struct super_operations autofs_sops = {
 106         .statfs         = simple_statfs,
 107         .show_options   = autofs_show_options,
 108         .evict_inode    = autofs_evict_inode,
 109 };
 110
 111 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 112         Opt_indirect, Opt_direct, Opt_offset};
 113
 114 static const match_table_t tokens = {
 115         {Opt_fd, "fd=%u"},
 116         {Opt_uid, "uid=%u"},
 117         {Opt_gid, "gid=%u"},
 118         {Opt_pgrp, "pgrp=%u"},
 119         {Opt_minproto, "minproto=%u"},
 120         {Opt_maxproto, "maxproto=%u"},
 121         {Opt_indirect, "indirect"},
 122         {Opt_direct, "direct"},
 123         {Opt_offset, "offset"},
 124         {Opt_err, NULL}
 125 };
 126
 127 static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
 128                          int *pgrp, bool *pgrp_set, unsigned int *type,
 129                          int *minproto, int *maxproto)
 130 {
 131         char *p;
 132         substring_t args[MAX_OPT_ARGS];
 133         int option;
 134
 135         *uid = current_uid();
 136         *gid = current_gid();
 137
 138         *minproto = AUTOFS_MIN_PROTO_VERSION;
 139         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 140
 141         *pipefd = -1;
 142
 143         if (!options)
 144                 return 1;
 145
 146         while ((p = strsep(&options, ",")) != NULL) {
 147                 int token;
 148
 149                 if (!*p)
 150                         continue;
 151
 152                 token = match_token(p, tokens, args);
 153                 switch (token) {
 154                 case Opt_fd:
 155                         if (match_int(args, pipefd))
 156                                 return 1;
 157                         break;
 158                 case Opt_uid:
 159                         if (match_int(args, &option))
 160                                 return 1;
 161                         *uid = make_kuid(current_user_ns(), option);
 162                         if (!uid_valid(*uid))
 163                                 return 1;
 164                         break;
 165                 case Opt_gid:
 166                         if (match_int(args, &option))
 167                                 return 1;
 168                         *gid = make_kgid(current_user_ns(), option);
 169                         if (!gid_valid(*gid))
 170                                 return 1;
 171                         break;
 172                 case Opt_pgrp:
 173                         if (match_int(args, &option))
 174                                 return 1;
 175                         *pgrp = option;
 176                         *pgrp_set = true;
 177                         break;
 178                 case Opt_minproto:
 179                         if (match_int(args, &option))
 180                                 return 1;
 181                         *minproto = option;
 182                         break;
 183                 case Opt_maxproto:
 184                         if (match_int(args, &option))
 185                                 return 1;
 186                         *maxproto = option;
 187                         break;
 188                 case Opt_indirect:
 189                         set_autofs_type_indirect(type);
 190                         break;
 191                 case Opt_direct:
 192                         set_autofs_type_direct(type);
 193                         break;
 194                 case Opt_offset:
 195                         set_autofs_type_offset(type);
 196                         break;
 197                 default:
 198                         return 1;
 199                 }
 200         }
 201         return (*pipefd < 0);
 202 }
 203
 204 int autofs_fill_super(struct super_block *s, void *data, int silent)
 205 {
 206         struct inode *root_inode;
 207         struct dentry *root;
 208         struct file *pipe;
 209         int pipefd;
 210         struct autofs_sb_info *sbi;
 211         struct autofs_info *ino;
 212         int pgrp = 0;
 213         bool pgrp_set = false;
 214         int ret = -EINVAL;
 215
 216         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 217         if (!sbi)
 218                 return -ENOMEM;
 219         pr_debug("starting up, sbi = %p\n", sbi);
 220
 221         s->s_fs_info = sbi;
 222         sbi->magic = AUTOFS_SBI_MAGIC;
 223         sbi->pipefd = -1;
 224         sbi->pipe = NULL;
 225         sbi->catatonic = 1;
 226         sbi->exp_timeout = 0;
 227         sbi->oz_pgrp = NULL;
 228         sbi->sb = s;
 229         sbi->version = 0;
 230         sbi->sub_version = 0;
 231         set_autofs_type_indirect(&sbi->type);
 232         sbi->min_proto = 0;
 233         sbi->max_proto = 0;
 234         mutex_init(&sbi->wq_mutex);
 235         mutex_init(&sbi->pipe_mutex);
 236         spin_lock_init(&sbi->fs_lock);
 237         sbi->queues = NULL;
 238         spin_lock_init(&sbi->lookup_lock);
 239         INIT_LIST_HEAD(&sbi->active_list);
 240         INIT_LIST_HEAD(&sbi->expiring_list);
 241         s->s_blocksize = 1024;
 242         s->s_blocksize_bits = 10;
 243         s->s_magic = AUTOFS_SUPER_MAGIC;
 244         s->s_op = &autofs_sops;
 245         s->s_d_op = &autofs_dentry_operations;
 246         s->s_time_gran = 1;
 247
 248         /*
 249          * Get the root inode and dentry, but defer checking for errors.
 250          */
 251         ino = autofs_new_ino(sbi);
 252         if (!ino) {
 253                 ret = -ENOMEM;
 254                 goto fail_free;
 255         }
 256         root_inode = autofs_get_inode(s, S_IFDIR | 0755);
 257         root = d_make_root(root_inode);
 258         if (!root)
 259                 goto fail_ino;
 260         pipe = NULL;
 261
 262         root->d_fsdata = ino;
 263
 264         /* Can this call block? */
 265         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 266                           &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
 267                           &sbi->max_proto)) {
 268                 pr_err("called with bogus options\n");
 269                 goto fail_dput;
 270         }
 271
 272         /* Test versions first */
 273         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 274             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 275                 pr_err("kernel does not match daemon version "
 276                        "daemon (%d, %d) kernel (%d, %d)\n",
 277                        sbi->min_proto, sbi->max_proto,
 278                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 279                 goto fail_dput;
 280         }
 281
 282         /* Establish highest kernel protocol version */
 283         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 284                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 285         else
 286                 sbi->version = sbi->max_proto;
 287         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 288
 289         if (pgrp_set) {
 290                 sbi->oz_pgrp = find_get_pid(pgrp);
 291                 if (!sbi->oz_pgrp) {
 292                         pr_err("could not find process group %d\n",
 293                                 pgrp);
 294                         goto fail_dput;
 295                 }
 296         } else {
 297                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 298         }
 299
 300         if (autofs_type_trigger(sbi->type))
 301                 __managed_dentry_set_managed(root);
 302
 303         root_inode->i_fop = &autofs_root_operations;
 304         root_inode->i_op = &autofs_dir_inode_operations;
 305
 306         pr_debug("pipe fd = %d, pgrp = %u\n", pipefd, pid_nr(sbi->oz_pgrp));
 307         pipe = fget(pipefd);
 308
 309         if (!pipe) {
 310                 pr_err("could not open pipe file descriptor\n");
 311                 goto fail_put_pid;
 312         }
 313         ret = autofs_prepare_pipe(pipe);
 314         if (ret < 0)
 315                 goto fail_fput;
 316         sbi->pipe = pipe;
 317         sbi->pipefd = pipefd;
 318         sbi->catatonic = 0;
 319
 320         /*
 321          * Success! Install the root dentry now to indicate completion.
 322          */
 323         s->s_root = root;
 324         return 0;
 325
 326         /*
 327          * Failure ... clean up.
 328          */
 329 fail_fput:
 330         pr_err("pipe file descriptor does not contain proper ops\n");
 331         fput(pipe);
 332 fail_put_pid:
 333         put_pid(sbi->oz_pgrp);
 334 fail_dput:
 335         dput(root);
 336         goto fail_free;
 337 fail_ino:
 338         autofs_free_ino(ino);
 339 fail_free:
 340         kfree(sbi);
 341         s->s_fs_info = NULL;
 342         return ret;
 343 }
 344
 345 struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
 346 {
 347         struct inode *inode = new_inode(sb);
 348
 349         if (inode == NULL)
 350                 return NULL;
 351
 352         inode->i_mode = mode;
 353         if (sb->s_root) {
 354                 inode->i_uid = d_inode(sb->s_root)->i_uid;
 355                 inode->i_gid = d_inode(sb->s_root)->i_gid;
 356         }
 357         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 358         inode->i_ino = get_next_ino();
 359
 360         if (S_ISDIR(mode)) {
 361                 set_nlink(inode, 2);
 362                 inode->i_op = &autofs_dir_inode_operations;
 363                 inode->i_fop = &autofs_dir_operations;
 364         } else if (S_ISLNK(mode)) {
 365                 inode->i_op = &autofs_symlink_inode_operations;
 366         } else
 367                 WARN_ON(1);
 368
 369         return inode;
 370 }