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