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_rcu(ino, rcu);
  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_puts(m, ",offset");
  86         else if (autofs_type_direct(sbi->type))
  87                 seq_puts(m, ",direct");
  88         else
  89                 seq_puts(m, ",indirect");
  90         if (sbi->flags & AUTOFS_SBI_STRICTEXPIRE)
  91                 seq_puts(m, ",strictexpire");
  92         if (sbi->flags & AUTOFS_SBI_IGNORE)
  93                 seq_puts(m, ",ignore");
  94 #ifdef CONFIG_CHECKPOINT_RESTORE
  95         if (sbi->pipe)
  96                 seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
  97         else
  98                 seq_puts(m, ",pipe_ino=-1");
  99 #endif
 100         return 0;
 101 }
 102
 103 static void autofs_evict_inode(struct inode *inode)
 104 {
 105         clear_inode(inode);
 106         kfree(inode->i_private);
 107 }
 108
 109 static const struct super_operations autofs_sops = {
 110         .statfs         = simple_statfs,
 111         .show_options   = autofs_show_options,
 112         .evict_inode    = autofs_evict_inode,
 113 };
 114
 115 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 116         Opt_indirect, Opt_direct, Opt_offset, Opt_strictexpire,
 117         Opt_ignore};
 118
 119 static const match_table_t tokens = {
 120         {Opt_fd, "fd=%u"},
 121         {Opt_uid, "uid=%u"},
 122         {Opt_gid, "gid=%u"},
 123         {Opt_pgrp, "pgrp=%u"},
 124         {Opt_minproto, "minproto=%u"},
 125         {Opt_maxproto, "maxproto=%u"},
 126         {Opt_indirect, "indirect"},
 127         {Opt_direct, "direct"},
 128         {Opt_offset, "offset"},
 129         {Opt_strictexpire, "strictexpire"},
 130         {Opt_ignore, "ignore"},
 131         {Opt_err, NULL}
 132 };
 133
 134 static int parse_options(char *options,
 135                          struct inode *root, int *pgrp, bool *pgrp_set,
 136                          struct autofs_sb_info *sbi)
 137 {
 138         char *p;
 139         substring_t args[MAX_OPT_ARGS];
 140         int option;
 141         int pipefd = -1;
 142         kuid_t uid;
 143         kgid_t gid;
 144
 145         root->i_uid = current_uid();
 146         root->i_gid = current_gid();
 147
 148         sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;
 149         sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;
 150
 151         sbi->pipefd = -1;
 152
 153         if (!options)
 154                 return 1;
 155
 156         while ((p = strsep(&options, ",")) != NULL) {
 157                 int token;
 158
 159                 if (!*p)
 160                         continue;
 161
 162                 token = match_token(p, tokens, args);
 163                 switch (token) {
 164                 case Opt_fd:
 165                         if (match_int(args, &pipefd))
 166                                 return 1;
 167                         sbi->pipefd = pipefd;
 168                         break;
 169                 case Opt_uid:
 170                         if (match_int(args, &option))
 171                                 return 1;
 172                         uid = make_kuid(current_user_ns(), option);
 173                         if (!uid_valid(uid))
 174                                 return 1;
 175                         root->i_uid = uid;
 176                         break;
 177                 case Opt_gid:
 178                         if (match_int(args, &option))
 179                                 return 1;
 180                         gid = make_kgid(current_user_ns(), option);
 181                         if (!gid_valid(gid))
 182                                 return 1;
 183                         root->i_gid = gid;
 184                         break;
 185                 case Opt_pgrp:
 186                         if (match_int(args, &option))
 187                                 return 1;
 188                         *pgrp = option;
 189                         *pgrp_set = true;
 190                         break;
 191                 case Opt_minproto:
 192                         if (match_int(args, &option))
 193                                 return 1;
 194                         sbi->min_proto = option;
 195                         break;
 196                 case Opt_maxproto:
 197                         if (match_int(args, &option))
 198                                 return 1;
 199                         sbi->max_proto = option;
 200                         break;
 201                 case Opt_indirect:
 202                         set_autofs_type_indirect(&sbi->type);
 203                         break;
 204                 case Opt_direct:
 205                         set_autofs_type_direct(&sbi->type);
 206                         break;
 207                 case Opt_offset:
 208                         set_autofs_type_offset(&sbi->type);
 209                         break;
 210                 case Opt_strictexpire:
 211                         sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
 212                         break;
 213                 case Opt_ignore:
 214                         sbi->flags |= AUTOFS_SBI_IGNORE;
 215                         break;
 216                 default:
 217                         return 1;
 218                 }
 219         }
 220         return (sbi->pipefd < 0);
 221 }
 222
 223 int autofs_fill_super(struct super_block *s, void *data, int silent)
 224 {
 225         struct inode *root_inode;
 226         struct dentry *root;
 227         struct file *pipe;
 228         struct autofs_sb_info *sbi;
 229         struct autofs_info *ino;
 230         int pgrp = 0;
 231         bool pgrp_set = false;
 232         int ret = -EINVAL;
 233
 234         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 235         if (!sbi)
 236                 return -ENOMEM;
 237         pr_debug("starting up, sbi = %p\n", sbi);
 238
 239         s->s_fs_info = sbi;
 240         sbi->magic = AUTOFS_SBI_MAGIC;
 241         sbi->pipefd = -1;
 242         sbi->pipe = NULL;
 243         sbi->exp_timeout = 0;
 244         sbi->oz_pgrp = NULL;
 245         sbi->sb = s;
 246         sbi->version = 0;
 247         sbi->sub_version = 0;
 248         sbi->flags = AUTOFS_SBI_CATATONIC;
 249         set_autofs_type_indirect(&sbi->type);
 250         sbi->min_proto = 0;
 251         sbi->max_proto = 0;
 252         mutex_init(&sbi->wq_mutex);
 253         mutex_init(&sbi->pipe_mutex);
 254         spin_lock_init(&sbi->fs_lock);
 255         sbi->queues = NULL;
 256         spin_lock_init(&sbi->lookup_lock);
 257         INIT_LIST_HEAD(&sbi->active_list);
 258         INIT_LIST_HEAD(&sbi->expiring_list);
 259         s->s_blocksize = 1024;
 260         s->s_blocksize_bits = 10;
 261         s->s_magic = AUTOFS_SUPER_MAGIC;
 262         s->s_op = &autofs_sops;
 263         s->s_d_op = &autofs_dentry_operations;
 264         s->s_time_gran = 1;
 265
 266         /*
 267          * Get the root inode and dentry, but defer checking for errors.
 268          */
 269         ino = autofs_new_ino(sbi);
 270         if (!ino) {
 271                 ret = -ENOMEM;
 272                 goto fail_free;
 273         }
 274         root_inode = autofs_get_inode(s, S_IFDIR | 0755);
 275         root = d_make_root(root_inode);
 276         if (!root) {
 277                 ret = -ENOMEM;
 278                 goto fail_ino;
 279         }
 280         pipe = NULL;
 281
 282         root->d_fsdata = ino;
 283
 284         /* Can this call block? */
 285         if (parse_options(data, root_inode, &pgrp, &pgrp_set, sbi)) {
 286                 pr_err("called with bogus options\n");
 287                 goto fail_dput;
 288         }
 289
 290         /* Test versions first */
 291         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 292             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 293                 pr_err("kernel does not match daemon version "
 294                        "daemon (%d, %d) kernel (%d, %d)\n",
 295                        sbi->min_proto, sbi->max_proto,
 296                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 297                 goto fail_dput;
 298         }
 299
 300         /* Establish highest kernel protocol version */
 301         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 302                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 303         else
 304                 sbi->version = sbi->max_proto;
 305         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 306
 307         if (pgrp_set) {
 308                 sbi->oz_pgrp = find_get_pid(pgrp);
 309                 if (!sbi->oz_pgrp) {
 310                         pr_err("could not find process group %d\n",
 311                                 pgrp);
 312                         goto fail_dput;
 313                 }
 314         } else {
 315                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 316         }
 317
 318         if (autofs_type_trigger(sbi->type))
 319                 __managed_dentry_set_managed(root);
 320
 321         root_inode->i_fop = &autofs_root_operations;
 322         root_inode->i_op = &autofs_dir_inode_operations;
 323
 324         pr_debug("pipe fd = %d, pgrp = %u\n",
 325                  sbi->pipefd, pid_nr(sbi->oz_pgrp));
 326         pipe = fget(sbi->pipefd);
 327
 328         if (!pipe) {
 329                 pr_err("could not open pipe file descriptor\n");
 330                 goto fail_put_pid;
 331         }
 332         ret = autofs_prepare_pipe(pipe);
 333         if (ret < 0)
 334                 goto fail_fput;
 335         sbi->pipe = pipe;
 336         sbi->flags &= ~AUTOFS_SBI_CATATONIC;
 337
 338         /*
 339          * Success! Install the root dentry now to indicate completion.
 340          */
 341         s->s_root = root;
 342         return 0;
 343
 344         /*
 345          * Failure ... clean up.
 346          */
 347 fail_fput:
 348         pr_err("pipe file descriptor does not contain proper ops\n");
 349         fput(pipe);
 350 fail_put_pid:
 351         put_pid(sbi->oz_pgrp);
 352 fail_dput:
 353         dput(root);
 354         goto fail_free;
 355 fail_ino:
 356         autofs_free_ino(ino);
 357 fail_free:
 358         kfree(sbi);
 359         s->s_fs_info = NULL;
 360         return ret;
 361 }
 362
 363 struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
 364 {
 365         struct inode *inode = new_inode(sb);
 366
 367         if (inode == NULL)
 368                 return NULL;
 369
 370         inode->i_mode = mode;
 371         if (sb->s_root) {
 372                 inode->i_uid = d_inode(sb->s_root)->i_uid;
 373                 inode->i_gid = d_inode(sb->s_root)->i_gid;
 374         }
 375         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 376         inode->i_ino = get_next_ino();
 377
 378         if (S_ISDIR(mode)) {
 379                 set_nlink(inode, 2);
 380                 inode->i_op = &autofs_dir_inode_operations;
 381                 inode->i_fop = &autofs_dir_operations;
 382         } else if (S_ISLNK(mode)) {
 383                 inode->i_op = &autofs_symlink_inode_operations;
 384         } else
 385                 WARN_ON(1);
 386
 387         return inode;
 388 }