fs/autofs4/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/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/file.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/parser.h>
  16 #include <linux/bitops.h>
  17 #include <linux/magic.h>
  18 #include "autofs_i.h"
  19 #include <linux/module.h>
  20
  21 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
  22 {
  23         struct autofs_info *ino;
  24
  25         ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  26         if (ino) {
  27                 INIT_LIST_HEAD(&ino->active);
  28                 INIT_LIST_HEAD(&ino->expiring);
  29                 ino->last_used = jiffies;
  30                 ino->sbi = sbi;
  31         }
  32         return ino;
  33 }
  34
  35 void autofs4_clean_ino(struct autofs_info *ino)
  36 {
  37         ino->uid = GLOBAL_ROOT_UID;
  38         ino->gid = GLOBAL_ROOT_GID;
  39         ino->last_used = jiffies;
  40 }
  41
  42 void autofs4_free_ino(struct autofs_info *ino)
  43 {
  44         kfree(ino);
  45 }
  46
  47 void autofs4_kill_sb(struct super_block *sb)
  48 {
  49         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  50
  51         /*
  52          * In the event of a failure in get_sb_nodev the superblock
  53          * info is not present so nothing else has been setup, so
  54          * just call kill_anon_super when we are called from
  55          * deactivate_super.
  56          */
  57         if (sbi) {
  58                 /* Free wait queues, close pipe */
  59                 autofs4_catatonic_mode(sbi);
  60                 put_pid(sbi->oz_pgrp);
  61         }
  62
  63         pr_debug("shutting down\n");
  64         kill_litter_super(sb);
  65         if (sbi)
  66                 kfree_rcu(sbi, rcu);
  67 }
  68
  69 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
  70 {
  71         struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
  72         struct inode *root_inode = d_inode(root->d_sb->s_root);
  73
  74         if (!sbi)
  75                 return 0;
  76
  77         seq_printf(m, ",fd=%d", sbi->pipefd);
  78         if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  79                 seq_printf(m, ",uid=%u",
  80                         from_kuid_munged(&init_user_ns, root_inode->i_uid));
  81         if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  82                 seq_printf(m, ",gid=%u",
  83                         from_kgid_munged(&init_user_ns, root_inode->i_gid));
  84         seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  85         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  86         seq_printf(m, ",minproto=%d", sbi->min_proto);
  87         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  88
  89         if (autofs_type_offset(sbi->type))
  90                 seq_printf(m, ",offset");
  91         else if (autofs_type_direct(sbi->type))
  92                 seq_printf(m, ",direct");
  93         else
  94                 seq_printf(m, ",indirect");
  95 #ifdef CONFIG_CHECKPOINT_RESTORE
  96         if (sbi->pipe)
  97                 seq_printf(m, ",pipe_ino=%ld", sbi->pipe->f_inode->i_ino);
  98         else
  99                 seq_printf(m, ",pipe_ino=-1");
 100 #endif
 101         return 0;
 102 }
 103
 104 static void autofs4_evict_inode(struct inode *inode)
 105 {
 106         clear_inode(inode);
 107         kfree(inode->i_private);
 108 }
 109
 110 static const struct super_operations autofs4_sops = {
 111         .statfs         = simple_statfs,
 112         .show_options   = autofs4_show_options,
 113         .evict_inode    = autofs4_evict_inode,
 114 };
 115
 116 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 117         Opt_indirect, Opt_direct, Opt_offset};
 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_err, NULL}
 130 };
 131
 132 static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
 133                          int *pgrp, bool *pgrp_set, unsigned int *type,
 134                          int *minproto, int *maxproto)
 135 {
 136         char *p;
 137         substring_t args[MAX_OPT_ARGS];
 138         int option;
 139
 140         *uid = current_uid();
 141         *gid = current_gid();
 142
 143         *minproto = AUTOFS_MIN_PROTO_VERSION;
 144         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 145
 146         *pipefd = -1;
 147
 148         if (!options)
 149                 return 1;
 150
 151         while ((p = strsep(&options, ",")) != NULL) {
 152                 int token;
 153
 154                 if (!*p)
 155                         continue;
 156
 157                 token = match_token(p, tokens, args);
 158                 switch (token) {
 159                 case Opt_fd:
 160                         if (match_int(args, pipefd))
 161                                 return 1;
 162                         break;
 163                 case Opt_uid:
 164                         if (match_int(args, &option))
 165                                 return 1;
 166                         *uid = make_kuid(current_user_ns(), option);
 167                         if (!uid_valid(*uid))
 168                                 return 1;
 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                         break;
 177                 case Opt_pgrp:
 178                         if (match_int(args, &option))
 179                                 return 1;
 180                         *pgrp = option;
 181                         *pgrp_set = true;
 182                         break;
 183                 case Opt_minproto:
 184                         if (match_int(args, &option))
 185                                 return 1;
 186                         *minproto = option;
 187                         break;
 188                 case Opt_maxproto:
 189                         if (match_int(args, &option))
 190                                 return 1;
 191                         *maxproto = option;
 192                         break;
 193                 case Opt_indirect:
 194                         set_autofs_type_indirect(type);
 195                         break;
 196                 case Opt_direct:
 197                         set_autofs_type_direct(type);
 198                         break;
 199                 case Opt_offset:
 200                         set_autofs_type_offset(type);
 201                         break;
 202                 default:
 203                         return 1;
 204                 }
 205         }
 206         return (*pipefd < 0);
 207 }
 208
 209 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 210 {
 211         struct inode *root_inode;
 212         struct dentry *root;
 213         struct file *pipe;
 214         int pipefd;
 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 = &autofs4_sops;
 250         s->s_d_op = &autofs4_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 = autofs4_new_ino(sbi);
 257         if (!ino) {
 258                 ret = -ENOMEM;
 259                 goto fail_free;
 260         }
 261         root_inode = autofs4_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, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 271                           &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
 272                           &sbi->max_proto)) {
 273                 pr_err("called with bogus options\n");
 274                 goto fail_dput;
 275         }
 276
 277         /* Test versions first */
 278         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 279             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 280                 pr_err("kernel does not match daemon version "
 281                        "daemon (%d, %d) kernel (%d, %d)\n",
 282                        sbi->min_proto, sbi->max_proto,
 283                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 284                 goto fail_dput;
 285         }
 286
 287         /* Establish highest kernel protocol version */
 288         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 289                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 290         else
 291                 sbi->version = sbi->max_proto;
 292         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 293
 294         if (pgrp_set) {
 295                 sbi->oz_pgrp = find_get_pid(pgrp);
 296                 if (!sbi->oz_pgrp) {
 297                         pr_err("could not find process group %d\n",
 298                                 pgrp);
 299                         goto fail_dput;
 300                 }
 301         } else {
 302                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 303         }
 304
 305         if (autofs_type_trigger(sbi->type))
 306                 __managed_dentry_set_managed(root);
 307
 308         root_inode->i_fop = &autofs4_root_operations;
 309         root_inode->i_op = &autofs4_dir_inode_operations;
 310
 311         pr_debug("pipe fd = %d, pgrp = %u\n", pipefd, pid_nr(sbi->oz_pgrp));
 312         pipe = fget(pipefd);
 313
 314         if (!pipe) {
 315                 pr_err("could not open pipe file descriptor\n");
 316                 goto fail_put_pid;
 317         }
 318         ret = autofs_prepare_pipe(pipe);
 319         if (ret < 0)
 320                 goto fail_fput;
 321         sbi->pipe = pipe;
 322         sbi->pipefd = pipefd;
 323         sbi->catatonic = 0;
 324
 325         /*
 326          * Success! Install the root dentry now to indicate completion.
 327          */
 328         s->s_root = root;
 329         return 0;
 330
 331         /*
 332          * Failure ... clean up.
 333          */
 334 fail_fput:
 335         pr_err("pipe file descriptor does not contain proper ops\n");
 336         fput(pipe);
 337 fail_put_pid:
 338         put_pid(sbi->oz_pgrp);
 339 fail_dput:
 340         dput(root);
 341         goto fail_free;
 342 fail_ino:
 343         autofs4_free_ino(ino);
 344 fail_free:
 345         kfree(sbi);
 346         s->s_fs_info = NULL;
 347         return ret;
 348 }
 349
 350 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
 351 {
 352         struct inode *inode = new_inode(sb);
 353
 354         if (inode == NULL)
 355                 return NULL;
 356
 357         inode->i_mode = mode;
 358         if (sb->s_root) {
 359                 inode->i_uid = d_inode(sb->s_root)->i_uid;
 360                 inode->i_gid = d_inode(sb->s_root)->i_gid;
 361         }
 362         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 363         inode->i_ino = get_next_ino();
 364
 365         if (S_ISDIR(mode)) {
 366                 set_nlink(inode, 2);
 367                 inode->i_op = &autofs4_dir_inode_operations;
 368                 inode->i_fop = &autofs4_dir_operations;
 369         } else if (S_ISLNK(mode)) {
 370                 inode->i_op = &autofs4_symlink_inode_operations;
 371         } else
 372                 WARN_ON(1);
 373
 374         return inode;
 375 }