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