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 "autofs_i.h"
  18 #include <linux/module.h>
  19
  20 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
  21 {
  22         struct autofs_info *ino;
  23
  24         ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  25         if (ino) {
  26                 INIT_LIST_HEAD(&ino->active);
  27                 INIT_LIST_HEAD(&ino->expiring);
  28                 ino->last_used = jiffies;
  29                 ino->sbi = sbi;
  30         }
  31         return ino;
  32 }
  33
  34 void autofs4_clean_ino(struct autofs_info *ino)
  35 {
  36         ino->uid = GLOBAL_ROOT_UID;
  37         ino->gid = GLOBAL_ROOT_GID;
  38         ino->last_used = jiffies;
  39 }
  40
  41 void autofs4_free_ino(struct autofs_info *ino)
  42 {
  43         kfree(ino);
  44 }
  45
  46 void autofs4_kill_sb(struct super_block *sb)
  47 {
  48         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  49
  50         /*
  51          * In the event of a failure in get_sb_nodev the superblock
  52          * info is not present so nothing else has been setup, so
  53          * just call kill_anon_super when we are called from
  54          * deactivate_super.
  55          */
  56         if (sbi) {
  57                 /* Free wait queues, close pipe */
  58                 autofs4_catatonic_mode(sbi);
  59                 put_pid(sbi->oz_pgrp);
  60         }
  61
  62         pr_debug("shutting down\n");
  63         kill_litter_super(sb);
  64         if (sbi)
  65                 kfree_rcu(sbi, rcu);
  66 }
  67
  68 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
  69 {
  70         struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
  71         struct inode *root_inode = d_inode(root->d_sb->s_root);
  72
  73         if (!sbi)
  74                 return 0;
  75
  76         seq_printf(m, ",fd=%d", sbi->pipefd);
  77         if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  78                 seq_printf(m, ",uid=%u",
  79                         from_kuid_munged(&init_user_ns, root_inode->i_uid));
  80         if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  81                 seq_printf(m, ",gid=%u",
  82                         from_kgid_munged(&init_user_ns, root_inode->i_gid));
  83         seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  84         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  85         seq_printf(m, ",minproto=%d", sbi->min_proto);
  86         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  87
  88         if (autofs_type_offset(sbi->type))
  89                 seq_printf(m, ",offset");
  90         else if (autofs_type_direct(sbi->type))
  91                 seq_printf(m, ",direct");
  92         else
  93                 seq_printf(m, ",indirect");
  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_printf(m, ",pipe_ino=-1");
  99 #endif
 100         return 0;
 101 }
 102
 103 static void autofs4_evict_inode(struct inode *inode)
 104 {
 105         clear_inode(inode);
 106         kfree(inode->i_private);
 107 }
 108
 109 static const struct super_operations autofs4_sops = {
 110         .statfs         = simple_statfs,
 111         .show_options   = autofs4_show_options,
 112         .evict_inode    = autofs4_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};
 117
 118 static const match_table_t tokens = {
 119         {Opt_fd, "fd=%u"},
 120         {Opt_uid, "uid=%u"},
 121         {Opt_gid, "gid=%u"},
 122         {Opt_pgrp, "pgrp=%u"},
 123         {Opt_minproto, "minproto=%u"},
 124         {Opt_maxproto, "maxproto=%u"},
 125         {Opt_indirect, "indirect"},
 126         {Opt_direct, "direct"},
 127         {Opt_offset, "offset"},
 128         {Opt_err, NULL}
 129 };
 130
 131 static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
 132                          int *pgrp, bool *pgrp_set, unsigned int *type,
 133                          int *minproto, int *maxproto)
 134 {
 135         char *p;
 136         substring_t args[MAX_OPT_ARGS];
 137         int option;
 138
 139         *uid = current_uid();
 140         *gid = current_gid();
 141
 142         *minproto = AUTOFS_MIN_PROTO_VERSION;
 143         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 144
 145         *pipefd = -1;
 146
 147         if (!options)
 148                 return 1;
 149
 150         while ((p = strsep(&options, ",")) != NULL) {
 151                 int token;
 152
 153                 if (!*p)
 154                         continue;
 155
 156                 token = match_token(p, tokens, args);
 157                 switch (token) {
 158                 case Opt_fd:
 159                         if (match_int(args, pipefd))
 160                                 return 1;
 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                         break;
 169                 case Opt_gid:
 170                         if (match_int(args, &option))
 171                                 return 1;
 172                         *gid = make_kgid(current_user_ns(), option);
 173                         if (!gid_valid(*gid))
 174                                 return 1;
 175                         break;
 176                 case Opt_pgrp:
 177                         if (match_int(args, &option))
 178                                 return 1;
 179                         *pgrp = option;
 180                         *pgrp_set = true;
 181                         break;
 182                 case Opt_minproto:
 183                         if (match_int(args, &option))
 184                                 return 1;
 185                         *minproto = option;
 186                         break;
 187                 case Opt_maxproto:
 188                         if (match_int(args, &option))
 189                                 return 1;
 190                         *maxproto = option;
 191                         break;
 192                 case Opt_indirect:
 193                         set_autofs_type_indirect(type);
 194                         break;
 195                 case Opt_direct:
 196                         set_autofs_type_direct(type);
 197                         break;
 198                 case Opt_offset:
 199                         set_autofs_type_offset(type);
 200                         break;
 201                 default:
 202                         return 1;
 203                 }
 204         }
 205         return (*pipefd < 0);
 206 }
 207
 208 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 209 {
 210         struct inode *root_inode;
 211         struct dentry *root;
 212         struct file *pipe;
 213         int pipefd;
 214         struct autofs_sb_info *sbi;
 215         struct autofs_info *ino;
 216         int pgrp = 0;
 217         bool pgrp_set = false;
 218         int ret = -EINVAL;
 219
 220         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 221         if (!sbi)
 222                 return -ENOMEM;
 223         pr_debug("starting up, sbi = %p\n", sbi);
 224
 225         s->s_fs_info = sbi;
 226         sbi->magic = AUTOFS_SBI_MAGIC;
 227         sbi->pipefd = -1;
 228         sbi->pipe = NULL;
 229         sbi->catatonic = 1;
 230         sbi->exp_timeout = 0;
 231         sbi->oz_pgrp = NULL;
 232         sbi->sb = s;
 233         sbi->version = 0;
 234         sbi->sub_version = 0;
 235         set_autofs_type_indirect(&sbi->type);
 236         sbi->min_proto = 0;
 237         sbi->max_proto = 0;
 238         mutex_init(&sbi->wq_mutex);
 239         mutex_init(&sbi->pipe_mutex);
 240         spin_lock_init(&sbi->fs_lock);
 241         sbi->queues = NULL;
 242         spin_lock_init(&sbi->lookup_lock);
 243         INIT_LIST_HEAD(&sbi->active_list);
 244         INIT_LIST_HEAD(&sbi->expiring_list);
 245         s->s_blocksize = 1024;
 246         s->s_blocksize_bits = 10;
 247         s->s_magic = AUTOFS_SUPER_MAGIC;
 248         s->s_op = &autofs4_sops;
 249         s->s_d_op = &autofs4_dentry_operations;
 250         s->s_time_gran = 1;
 251
 252         /*
 253          * Get the root inode and dentry, but defer checking for errors.
 254          */
 255         ino = autofs4_new_ino(sbi);
 256         if (!ino) {
 257                 ret = -ENOMEM;
 258                 goto fail_free;
 259         }
 260         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
 261         root = d_make_root(root_inode);
 262         if (!root) {
 263                 ret = -ENOMEM;
 264                 goto fail_ino;
 265         }
 266         pipe = NULL;
 267
 268         root->d_fsdata = ino;
 269
 270         /* Can this call block? */
 271         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 272                           &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
 273                           &sbi->max_proto)) {
 274                 pr_err("called with bogus options\n");
 275                 goto fail_dput;
 276         }
 277
 278         /* Test versions first */
 279         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 280             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 281                 pr_err("kernel does not match daemon version "
 282                        "daemon (%d, %d) kernel (%d, %d)\n",
 283                        sbi->min_proto, sbi->max_proto,
 284                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 285                 goto fail_dput;
 286         }
 287
 288         /* Establish highest kernel protocol version */
 289         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 290                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 291         else
 292                 sbi->version = sbi->max_proto;
 293         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 294
 295         if (pgrp_set) {
 296                 sbi->oz_pgrp = find_get_pid(pgrp);
 297                 if (!sbi->oz_pgrp) {
 298                         pr_err("could not find process group %d\n",
 299                                 pgrp);
 300                         goto fail_dput;
 301                 }
 302         } else {
 303                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 304         }
 305
 306         if (autofs_type_trigger(sbi->type))
 307                 __managed_dentry_set_managed(root);
 308
 309         root_inode->i_fop = &autofs4_root_operations;
 310         root_inode->i_op = &autofs4_dir_inode_operations;
 311
 312         pr_debug("pipe fd = %d, pgrp = %u\n", pipefd, pid_nr(sbi->oz_pgrp));
 313         pipe = fget(pipefd);
 314
 315         if (!pipe) {
 316                 pr_err("could not open pipe file descriptor\n");
 317                 goto fail_put_pid;
 318         }
 319         ret = autofs_prepare_pipe(pipe);
 320         if (ret < 0)
 321                 goto fail_fput;
 322         sbi->pipe = pipe;
 323         sbi->pipefd = pipefd;
 324         sbi->catatonic = 0;
 325
 326         /*
 327          * Success! Install the root dentry now to indicate completion.
 328          */
 329         s->s_root = root;
 330         return 0;
 331
 332         /*
 333          * Failure ... clean up.
 334          */
 335 fail_fput:
 336         pr_err("pipe file descriptor does not contain proper ops\n");
 337         fput(pipe);
 338 fail_put_pid:
 339         put_pid(sbi->oz_pgrp);
 340 fail_dput:
 341         dput(root);
 342         goto fail_free;
 343 fail_ino:
 344         autofs4_free_ino(ino);
 345 fail_free:
 346         kfree(sbi);
 347         s->s_fs_info = NULL;
 348         return ret;
 349 }
 350
 351 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
 352 {
 353         struct inode *inode = new_inode(sb);
 354
 355         if (inode == NULL)
 356                 return NULL;
 357
 358         inode->i_mode = mode;
 359         if (sb->s_root) {
 360                 inode->i_uid = d_inode(sb->s_root)->i_uid;
 361                 inode->i_gid = d_inode(sb->s_root)->i_gid;
 362         }
 363         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 364         inode->i_ino = get_next_ino();
 365
 366         if (S_ISDIR(mode)) {
 367                 set_nlink(inode, 2);
 368                 inode->i_op = &autofs4_dir_inode_operations;
 369                 inode->i_fop = &autofs4_dir_operations;
 370         } else if (S_ISLNK(mode)) {
 371                 inode->i_op = &autofs4_symlink_inode_operations;
 372         } else
 373                 WARN_ON(1);
 374
 375         return inode;
 376 }