fs/autofs4/inode.c

   1 /* -*- c -*- --------------------------------------------------------------- *
   2  *
   3  * linux/fs/autofs/inode.c
   4  *
   5  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   6  *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
   7  *
   8  * This file is part of the Linux kernel and is made available under
   9  * the terms of the GNU General Public License, version 2, or at your
  10  * option, any later version, incorporated herein by reference.
  11  *
  12  * ------------------------------------------------------------------------- */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/file.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/parser.h>
  20 #include <linux/bitops.h>
  21 #include "autofs_i.h"
  22 #include <linux/module.h>
  23
  24 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
  25 {
  26         struct autofs_info *ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  27         if (ino) {
  28                 INIT_LIST_HEAD(&ino->active);
  29                 INIT_LIST_HEAD(&ino->expiring);
  30                 ino->last_used = jiffies;
  31                 ino->sbi = sbi;
  32         }
  33         return ino;
  34 }
  35
  36 void autofs4_clean_ino(struct autofs_info *ino)
  37 {
  38         ino->uid = GLOBAL_ROOT_UID;
  39         ino->gid = GLOBAL_ROOT_GID;
  40         ino->last_used = jiffies;
  41 }
  42
  43 void autofs4_free_ino(struct autofs_info *ino)
  44 {
  45         kfree(ino);
  46 }
  47
  48 void autofs4_kill_sb(struct super_block *sb)
  49 {
  50         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  51
  52         /*
  53          * In the event of a failure in get_sb_nodev the superblock
  54          * info is not present so nothing else has been setup, so
  55          * just call kill_anon_super when we are called from
  56          * deactivate_super.
  57          */
  58         if (sbi) {
  59                 /* Free wait queues, close pipe */
  60                 autofs4_catatonic_mode(sbi);
  61                 put_pid(sbi->oz_pgrp);
  62         }
  63
  64         DPRINTK("shutting down");
  65         kill_litter_super(sb);
  66         if (sbi)
  67                 kfree_rcu(sbi, rcu);
  68 }
  69
  70 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
  71 {
  72         struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
  73         struct inode *root_inode = d_inode(root->d_sb->s_root);
  74
  75         if (!sbi)
  76                 return 0;
  77
  78         seq_printf(m, ",fd=%d", sbi->pipefd);
  79         if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  80                 seq_printf(m, ",uid=%u",
  81                         from_kuid_munged(&init_user_ns, root_inode->i_uid));
  82         if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  83                 seq_printf(m, ",gid=%u",
  84                         from_kgid_munged(&init_user_ns, root_inode->i_gid));
  85         seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  86         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  87         seq_printf(m, ",minproto=%d", sbi->min_proto);
  88         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  89
  90         if (autofs_type_offset(sbi->type))
  91                 seq_printf(m, ",offset");
  92         else if (autofs_type_direct(sbi->type))
  93                 seq_printf(m, ",direct");
  94         else
  95                 seq_printf(m, ",indirect");
  96
  97         return 0;
  98 }
  99
 100 static void autofs4_evict_inode(struct inode *inode)
 101 {
 102         clear_inode(inode);
 103         kfree(inode->i_private);
 104 }
 105
 106 static const struct super_operations autofs4_sops = {
 107         .statfs         = simple_statfs,
 108         .show_options   = autofs4_show_options,
 109         .evict_inode    = autofs4_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                 if (!*p)
 150                         continue;
 151
 152                 token = match_token(p, tokens, args);
 153                 switch (token) {
 154                 case Opt_fd:
 155                         if (match_int(args, pipefd))
 156                                 return 1;
 157                         break;
 158                 case Opt_uid:
 159                         if (match_int(args, &option))
 160                                 return 1;
 161                         *uid = make_kuid(current_user_ns(), option);
 162                         if (!uid_valid(*uid))
 163                                 return 1;
 164                         break;
 165                 case Opt_gid:
 166                         if (match_int(args, &option))
 167                                 return 1;
 168                         *gid = make_kgid(current_user_ns(), option);
 169                         if (!gid_valid(*gid))
 170                                 return 1;
 171                         break;
 172                 case Opt_pgrp:
 173                         if (match_int(args, &option))
 174                                 return 1;
 175                         *pgrp = option;
 176                         *pgrp_set = true;
 177                         break;
 178                 case Opt_minproto:
 179                         if (match_int(args, &option))
 180                                 return 1;
 181                         *minproto = option;
 182                         break;
 183                 case Opt_maxproto:
 184                         if (match_int(args, &option))
 185                                 return 1;
 186                         *maxproto = option;
 187                         break;
 188                 case Opt_indirect:
 189                         set_autofs_type_indirect(type);
 190                         break;
 191                 case Opt_direct:
 192                         set_autofs_type_direct(type);
 193                         break;
 194                 case Opt_offset:
 195                         set_autofs_type_offset(type);
 196                         break;
 197                 default:
 198                         return 1;
 199                 }
 200         }
 201         return (*pipefd < 0);
 202 }
 203
 204 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 205 {
 206         struct inode * root_inode;
 207         struct dentry * root;
 208         struct file * pipe;
 209         int pipefd;
 210         struct autofs_sb_info *sbi;
 211         struct autofs_info *ino;
 212         int pgrp = 0;
 213         bool pgrp_set = false;
 214         int ret = -EINVAL;
 215
 216         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 217         if (!sbi)
 218                 return -ENOMEM;
 219         DPRINTK("starting up, sbi = %p",sbi);
 220
 221         s->s_fs_info = sbi;
 222         sbi->magic = AUTOFS_SBI_MAGIC;
 223         sbi->pipefd = -1;
 224         sbi->pipe = NULL;
 225         sbi->catatonic = 1;
 226         sbi->exp_timeout = 0;
 227         sbi->oz_pgrp = NULL;
 228         sbi->sb = s;
 229         sbi->version = 0;
 230         sbi->sub_version = 0;
 231         set_autofs_type_indirect(&sbi->type);
 232         sbi->min_proto = 0;
 233         sbi->max_proto = 0;
 234         mutex_init(&sbi->wq_mutex);
 235         mutex_init(&sbi->pipe_mutex);
 236         spin_lock_init(&sbi->fs_lock);
 237         sbi->queues = NULL;
 238         spin_lock_init(&sbi->lookup_lock);
 239         INIT_LIST_HEAD(&sbi->active_list);
 240         INIT_LIST_HEAD(&sbi->expiring_list);
 241         s->s_blocksize = 1024;
 242         s->s_blocksize_bits = 10;
 243         s->s_magic = AUTOFS_SUPER_MAGIC;
 244         s->s_op = &autofs4_sops;
 245         s->s_d_op = &autofs4_dentry_operations;
 246         s->s_time_gran = 1;
 247
 248         /*
 249          * Get the root inode and dentry, but defer checking for errors.
 250          */
 251         ino = autofs4_new_ino(sbi);
 252         if (!ino) {
 253                 ret = -ENOMEM;
 254                 goto fail_free;
 255         }
 256         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
 257         root = d_make_root(root_inode);
 258         if (!root) {
 259                 ret = -ENOMEM;
 260                 goto fail_ino;
 261         }
 262         pipe = NULL;
 263
 264         root->d_fsdata = ino;
 265
 266         /* Can this call block? */
 267         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 268                           &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
 269                           &sbi->max_proto)) {
 270                 printk("autofs: called with bogus options\n");
 271                 goto fail_dput;
 272         }
 273
 274         if (pgrp_set) {
 275                 sbi->oz_pgrp = find_get_pid(pgrp);
 276                 if (!sbi->oz_pgrp) {
 277                         pr_warn("autofs: could not find process group %d\n",
 278                                 pgrp);
 279                         goto fail_dput;
 280                 }
 281         } else {
 282                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 283         }
 284
 285         if (autofs_type_trigger(sbi->type))
 286                 __managed_dentry_set_managed(root);
 287
 288         root_inode->i_fop = &autofs4_root_operations;
 289         root_inode->i_op = &autofs4_dir_inode_operations;
 290
 291         /* Couldn't this be tested earlier? */
 292         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 293             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 294                 printk("autofs: kernel does not match daemon version "
 295                        "daemon (%d, %d) kernel (%d, %d)\n",
 296                         sbi->min_proto, sbi->max_proto,
 297                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 298                 goto fail_dput;
 299         }
 300
 301         /* Establish highest kernel protocol version */
 302         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 303                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 304         else
 305                 sbi->version = sbi->max_proto;
 306         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 307
 308         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, pid_nr(sbi->oz_pgrp));
 309         pipe = fget(pipefd);
 310
 311         if (!pipe) {
 312                 printk("autofs: could not open pipe file descriptor\n");
 313                 goto fail_dput;
 314         }
 315         ret = autofs_prepare_pipe(pipe);
 316         if (ret < 0)
 317                 goto fail_fput;
 318         sbi->pipe = pipe;
 319         sbi->pipefd = pipefd;
 320         sbi->catatonic = 0;
 321
 322         /*
 323          * Success! Install the root dentry now to indicate completion.
 324          */
 325         s->s_root = root;
 326         return 0;
 327
 328         /*
 329          * Failure ... clean up.
 330          */
 331 fail_fput:
 332         printk("autofs: pipe file descriptor does not contain proper ops\n");
 333         fput(pipe);
 334         /* fall through */
 335 fail_dput:
 336         dput(root);
 337         goto fail_free;
 338 fail_ino:
 339         kfree(ino);
 340 fail_free:
 341         put_pid(sbi->oz_pgrp);
 342         kfree(sbi);
 343         s->s_fs_info = NULL;
 344         return ret;
 345 }
 346
 347 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
 348 {
 349         struct inode *inode = new_inode(sb);
 350
 351         if (inode == NULL)
 352                 return NULL;
 353
 354         inode->i_mode = mode;
 355         if (sb->s_root) {
 356                 inode->i_uid = d_inode(sb->s_root)->i_uid;
 357                 inode->i_gid = d_inode(sb->s_root)->i_gid;
 358         }
 359         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 360         inode->i_ino = get_next_ino();
 361
 362         if (S_ISDIR(mode)) {
 363                 set_nlink(inode, 2);
 364                 inode->i_op = &autofs4_dir_inode_operations;
 365                 inode->i_fop = &autofs4_dir_operations;
 366         } else if (S_ISLNK(mode)) {
 367                 inode->i_op = &autofs4_symlink_inode_operations;
 368         }
 369
 370         return inode;
 371 }