fs/autofs/inode.c

   1 /*
   2  * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   3  * Copyright 2005-2006 Ian Kent <[email protected]>
   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 #include <linux/magic.h>
  14
  15 #include "autofs_i.h"
  16
  17 struct autofs_info *autofs_new_ino(struct autofs_sb_info *sbi)
  18 {
  19         struct autofs_info *ino;
  20
  21         ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  22         if (ino) {
  23                 INIT_LIST_HEAD(&ino->active);
  24                 INIT_LIST_HEAD(&ino->expiring);
  25                 ino->last_used = jiffies;
  26                 ino->sbi = sbi;
  27         }
  28         return ino;
  29 }
  30
  31 void autofs_clean_ino(struct autofs_info *ino)
  32 {
  33         ino->uid = GLOBAL_ROOT_UID;
  34         ino->gid = GLOBAL_ROOT_GID;
  35         ino->last_used = jiffies;
  36 }
  37
  38 void autofs_free_ino(struct autofs_info *ino)
  39 {
  40         kfree(ino);
  41 }
  42
  43 void autofs_kill_sb(struct super_block *sb)
  44 {
  45         struct autofs_sb_info *sbi = autofs_sbi(sb);
  46
  47         /*
  48          * In the event of a failure in get_sb_nodev the superblock
  49          * info is not present so nothing else has been setup, so
  50          * just call kill_anon_super when we are called from
  51          * deactivate_super.
  52          */
  53         if (sbi) {
  54                 /* Free wait queues, close pipe */
  55                 autofs_catatonic_mode(sbi);
  56                 put_pid(sbi->oz_pgrp);
  57         }
  58
  59         pr_debug("shutting down\n");
  60         kill_litter_super(sb);
  61         if (sbi)
  62                 kfree_rcu(sbi, rcu);
  63 }
  64
  65 static int autofs_show_options(struct seq_file *m, struct dentry *root)
  66 {
  67         struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
  68         struct inode *root_inode = d_inode(root->d_sb->s_root);
  69
  70         if (!sbi)
  71                 return 0;
  72
  73         seq_printf(m, ",fd=%d", sbi->pipefd);
  74         if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  75                 seq_printf(m, ",uid=%u",
  76                         from_kuid_munged(&init_user_ns, root_inode->i_uid));
  77         if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  78                 seq_printf(m, ",gid=%u",
  79                         from_kgid_munged(&init_user_ns, root_inode->i_gid));
  80         seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  81         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  82         seq_printf(m, ",minproto=%d", sbi->min_proto);
  83         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  84
  85         if (autofs_type_offset(sbi->type))
  86                 seq_printf(m, ",offset");
  87         else if (autofs_type_direct(sbi->type))
  88                 seq_printf(m, ",direct");
  89         else
  90                 seq_printf(m, ",indirect");
  91 #ifdef CONFIG_CHECKPOINT_RESTORE
  92         if (sbi->pipe)
  93                 seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
  94         else
  95                 seq_printf(m, ",pipe_ino=-1");
  96 #endif
  97         return 0;
  98 }
  99
 100 static void autofs_evict_inode(struct inode *inode)
 101 {
 102         clear_inode(inode);
 103         kfree(inode->i_private);
 104 }
 105
 106 static const struct super_operations autofs_sops = {
 107         .statfs         = simple_statfs,
 108         .show_options   = autofs_show_options,
 109         .evict_inode    = autofs_evict_inode,
 110 };
 111
 112 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 113         Opt_indirect, Opt_direct, Opt_offset};
 114
 115 static const match_table_t tokens = {
 116         {Opt_fd, "fd=%u"},
 117         {Opt_uid, "uid=%u"},
 118         {Opt_gid, "gid=%u"},
 119         {Opt_pgrp, "pgrp=%u"},
 120         {Opt_minproto, "minproto=%u"},
 121         {Opt_maxproto, "maxproto=%u"},
 122         {Opt_indirect, "indirect"},
 123         {Opt_direct, "direct"},
 124         {Opt_offset, "offset"},
 125         {Opt_err, NULL}
 126 };
 127
 128 static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
 129                          int *pgrp, bool *pgrp_set, unsigned int *type,
 130                          int *minproto, int *maxproto)
 131 {
 132         char *p;
 133         substring_t args[MAX_OPT_ARGS];
 134         int option;
 135
 136         *uid = current_uid();
 137         *gid = current_gid();
 138
 139         *minproto = AUTOFS_MIN_PROTO_VERSION;
 140         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 141
 142         *pipefd = -1;
 143
 144         if (!options)
 145                 return 1;
 146
 147         while ((p = strsep(&options, ",")) != NULL) {
 148                 int token;
 149
 150                 if (!*p)
 151                         continue;
 152
 153                 token = match_token(p, tokens, args);
 154                 switch (token) {
 155                 case Opt_fd:
 156                         if (match_int(args, pipefd))
 157                                 return 1;
 158                         break;
 159                 case Opt_uid:
 160                         if (match_int(args, &option))
 161                                 return 1;
 162                         *uid = make_kuid(current_user_ns(), option);
 163                         if (!uid_valid(*uid))
 164                                 return 1;
 165                         break;
 166                 case Opt_gid:
 167                         if (match_int(args, &option))
 168                                 return 1;
 169                         *gid = make_kgid(current_user_ns(), option);
 170                         if (!gid_valid(*gid))
 171                                 return 1;
 172                         break;
 173                 case Opt_pgrp:
 174                         if (match_int(args, &option))
 175                                 return 1;
 176                         *pgrp = option;
 177                         *pgrp_set = true;
 178                         break;
 179                 case Opt_minproto:
 180                         if (match_int(args, &option))
 181                                 return 1;
 182                         *minproto = option;
 183                         break;
 184                 case Opt_maxproto:
 185                         if (match_int(args, &option))
 186                                 return 1;
 187                         *maxproto = option;
 188                         break;
 189                 case Opt_indirect:
 190                         set_autofs_type_indirect(type);
 191                         break;
 192                 case Opt_direct:
 193                         set_autofs_type_direct(type);
 194                         break;
 195                 case Opt_offset:
 196                         set_autofs_type_offset(type);
 197                         break;
 198                 default:
 199                         return 1;
 200                 }
 201         }
 202         return (*pipefd < 0);
 203 }
 204
 205 int autofs_fill_super(struct super_block *s, void *data, int silent)
 206 {
 207         struct inode *root_inode;
 208         struct dentry *root;
 209         struct file *pipe;
 210         int pipefd;
 211         struct autofs_sb_info *sbi;
 212         struct autofs_info *ino;
 213         int pgrp = 0;
 214         bool pgrp_set = false;
 215         int ret = -EINVAL;
 216
 217         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 218         if (!sbi)
 219                 return -ENOMEM;
 220         pr_debug("starting up, sbi = %p\n", sbi);
 221
 222         s->s_fs_info = sbi;
 223         sbi->magic = AUTOFS_SBI_MAGIC;
 224         sbi->pipefd = -1;
 225         sbi->pipe = NULL;
 226         sbi->catatonic = 1;
 227         sbi->exp_timeout = 0;
 228         sbi->oz_pgrp = NULL;
 229         sbi->sb = s;
 230         sbi->version = 0;
 231         sbi->sub_version = 0;
 232         set_autofs_type_indirect(&sbi->type);
 233         sbi->min_proto = 0;
 234         sbi->max_proto = 0;
 235         mutex_init(&sbi->wq_mutex);
 236         mutex_init(&sbi->pipe_mutex);
 237         spin_lock_init(&sbi->fs_lock);
 238         sbi->queues = NULL;
 239         spin_lock_init(&sbi->lookup_lock);
 240         INIT_LIST_HEAD(&sbi->active_list);
 241         INIT_LIST_HEAD(&sbi->expiring_list);
 242         s->s_blocksize = 1024;
 243         s->s_blocksize_bits = 10;
 244         s->s_magic = AUTOFS_SUPER_MAGIC;
 245         s->s_op = &autofs_sops;
 246         s->s_d_op = &autofs_dentry_operations;
 247         s->s_time_gran = 1;
 248
 249         /*
 250          * Get the root inode and dentry, but defer checking for errors.
 251          */
 252         ino = autofs_new_ino(sbi);
 253         if (!ino) {
 254                 ret = -ENOMEM;
 255                 goto fail_free;
 256         }
 257         root_inode = autofs_get_inode(s, S_IFDIR | 0755);
 258         root = d_make_root(root_inode);
 259         if (!root)
 260                 goto fail_ino;
 261         pipe = NULL;
 262
 263         root->d_fsdata = ino;
 264
 265         /* Can this call block? */
 266         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 267                           &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
 268                           &sbi->max_proto)) {
 269                 pr_err("called with bogus options\n");
 270                 goto fail_dput;
 271         }
 272
 273         /* Test versions first */
 274         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 275             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 276                 pr_err("kernel does not match daemon version "
 277                        "daemon (%d, %d) kernel (%d, %d)\n",
 278                        sbi->min_proto, sbi->max_proto,
 279                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 280                 goto fail_dput;
 281         }
 282
 283         /* Establish highest kernel protocol version */
 284         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 285                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 286         else
 287                 sbi->version = sbi->max_proto;
 288         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 289
 290         if (pgrp_set) {
 291                 sbi->oz_pgrp = find_get_pid(pgrp);
 292                 if (!sbi->oz_pgrp) {
 293                         pr_err("could not find process group %d\n",
 294                                 pgrp);
 295                         goto fail_dput;
 296                 }
 297         } else {
 298                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 299         }
 300
 301         if (autofs_type_trigger(sbi->type))
 302                 __managed_dentry_set_managed(root);
 303
 304         root_inode->i_fop = &autofs_root_operations;
 305         root_inode->i_op = &autofs_dir_inode_operations;
 306
 307         pr_debug("pipe fd = %d, pgrp = %u\n", pipefd, pid_nr(sbi->oz_pgrp));
 308         pipe = fget(pipefd);
 309
 310         if (!pipe) {
 311                 pr_err("could not open pipe file descriptor\n");
 312                 goto fail_put_pid;
 313         }
 314         ret = autofs_prepare_pipe(pipe);
 315         if (ret < 0)
 316                 goto fail_fput;
 317         sbi->pipe = pipe;
 318         sbi->pipefd = pipefd;
 319         sbi->catatonic = 0;
 320
 321         /*
 322          * Success! Install the root dentry now to indicate completion.
 323          */
 324         s->s_root = root;
 325         return 0;
 326
 327         /*
 328          * Failure ... clean up.
 329          */
 330 fail_fput:
 331         pr_err("pipe file descriptor does not contain proper ops\n");
 332         fput(pipe);
 333 fail_put_pid:
 334         put_pid(sbi->oz_pgrp);
 335 fail_dput:
 336         dput(root);
 337         goto fail_free;
 338 fail_ino:
 339         autofs_free_ino(ino);
 340 fail_free:
 341         kfree(sbi);
 342         s->s_fs_info = NULL;
 343         return ret;
 344 }
 345
 346 struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
 347 {
 348         struct inode *inode = new_inode(sb);
 349
 350         if (inode == NULL)
 351                 return NULL;
 352
 353         inode->i_mode = mode;
 354         if (sb->s_root) {
 355                 inode->i_uid = d_inode(sb->s_root)->i_uid;
 356                 inode->i_gid = d_inode(sb->s_root)->i_gid;
 357         }
 358         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 359         inode->i_ino = get_next_ino();
 360
 361         if (S_ISDIR(mode)) {
 362                 set_nlink(inode, 2);
 363                 inode->i_op = &autofs_dir_inode_operations;
 364                 inode->i_fop = &autofs_dir_operations;
 365         } else if (S_ISLNK(mode)) {
 366                 inode->i_op = &autofs_symlink_inode_operations;
 367         } else
 368                 WARN_ON(1);
 369
 370         return inode;
 371 }