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 <linux/magic.h>
  22 #include <linux/compat.h>
  23 #include "autofs_i.h"
  24 #include <linux/module.h>
  25
  26 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
  27 {
  28         struct autofs_info *ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  29         if (ino) {
  30                 INIT_LIST_HEAD(&ino->active);
  31                 INIT_LIST_HEAD(&ino->expiring);
  32                 ino->last_used = jiffies;
  33                 ino->sbi = sbi;
  34         }
  35         return ino;
  36 }
  37
  38 void autofs4_clean_ino(struct autofs_info *ino)
  39 {
  40         ino->uid = 0;
  41         ino->gid = 0;
  42         ino->last_used = jiffies;
  43 }
  44
  45 void autofs4_free_ino(struct autofs_info *ino)
  46 {
  47         kfree(ino);
  48 }
  49
  50 void autofs4_kill_sb(struct super_block *sb)
  51 {
  52         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  53
  54         /*
  55          * In the event of a failure in get_sb_nodev the superblock
  56          * info is not present so nothing else has been setup, so
  57          * just call kill_anon_super when we are called from
  58          * deactivate_super.
  59          */
  60         if (!sbi)
  61                 goto out_kill_sb;
  62
  63         /* Free wait queues, close pipe */
  64         autofs4_catatonic_mode(sbi);
  65
  66         sb->s_fs_info = NULL;
  67         kfree(sbi);
  68
  69 out_kill_sb:
  70         DPRINTK("shutting down");
  71         kill_litter_super(sb);
  72 }
  73
  74 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
  75 {
  76         struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
  77         struct inode *root_inode = root->d_sb->s_root->d_inode;
  78
  79         if (!sbi)
  80                 return 0;
  81
  82         seq_printf(m, ",fd=%d", sbi->pipefd);
  83         if (root_inode->i_uid != 0)
  84                 seq_printf(m, ",uid=%u", root_inode->i_uid);
  85         if (root_inode->i_gid != 0)
  86                 seq_printf(m, ",gid=%u", root_inode->i_gid);
  87         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
  88         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  89         seq_printf(m, ",minproto=%d", sbi->min_proto);
  90         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  91
  92         if (autofs_type_offset(sbi->type))
  93                 seq_printf(m, ",offset");
  94         else if (autofs_type_direct(sbi->type))
  95                 seq_printf(m, ",direct");
  96         else
  97                 seq_printf(m, ",indirect");
  98
  99         return 0;
 100 }
 101
 102 static void autofs4_evict_inode(struct inode *inode)
 103 {
 104         end_writeback(inode);
 105         kfree(inode->i_private);
 106 }
 107
 108 static const struct super_operations autofs4_sops = {
 109         .statfs         = simple_statfs,
 110         .show_options   = autofs4_show_options,
 111         .evict_inode    = autofs4_evict_inode,
 112 };
 113
 114 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 115         Opt_indirect, Opt_direct, Opt_offset};
 116
 117 static const match_table_t tokens = {
 118         {Opt_fd, "fd=%u"},
 119         {Opt_uid, "uid=%u"},
 120         {Opt_gid, "gid=%u"},
 121         {Opt_pgrp, "pgrp=%u"},
 122         {Opt_minproto, "minproto=%u"},
 123         {Opt_maxproto, "maxproto=%u"},
 124         {Opt_indirect, "indirect"},
 125         {Opt_direct, "direct"},
 126         {Opt_offset, "offset"},
 127         {Opt_err, NULL}
 128 };
 129
 130 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 131                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 132 {
 133         char *p;
 134         substring_t args[MAX_OPT_ARGS];
 135         int option;
 136
 137         *uid = current_uid();
 138         *gid = current_gid();
 139         *pgrp = task_pgrp_nr(current);
 140
 141         *minproto = AUTOFS_MIN_PROTO_VERSION;
 142         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 143
 144         *pipefd = -1;
 145
 146         if (!options)
 147                 return 1;
 148
 149         while ((p = strsep(&options, ",")) != NULL) {
 150                 int token;
 151                 if (!*p)
 152                         continue;
 153
 154                 token = match_token(p, tokens, args);
 155                 switch (token) {
 156                 case Opt_fd:
 157                         if (match_int(args, pipefd))
 158                                 return 1;
 159                         break;
 160                 case Opt_uid:
 161                         if (match_int(args, &option))
 162                                 return 1;
 163                         *uid = option;
 164                         break;
 165                 case Opt_gid:
 166                         if (match_int(args, &option))
 167                                 return 1;
 168                         *gid = option;
 169                         break;
 170                 case Opt_pgrp:
 171                         if (match_int(args, &option))
 172                                 return 1;
 173                         *pgrp = option;
 174                         break;
 175                 case Opt_minproto:
 176                         if (match_int(args, &option))
 177                                 return 1;
 178                         *minproto = option;
 179                         break;
 180                 case Opt_maxproto:
 181                         if (match_int(args, &option))
 182                                 return 1;
 183                         *maxproto = option;
 184                         break;
 185                 case Opt_indirect:
 186                         set_autofs_type_indirect(type);
 187                         break;
 188                 case Opt_direct:
 189                         set_autofs_type_direct(type);
 190                         break;
 191                 case Opt_offset:
 192                         set_autofs_type_offset(type);
 193                         break;
 194                 default:
 195                         return 1;
 196                 }
 197         }
 198         return (*pipefd < 0);
 199 }
 200
 201 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 202 {
 203         struct inode * root_inode;
 204         struct dentry * root;
 205         struct file * pipe;
 206         int pipefd;
 207         struct autofs_sb_info *sbi;
 208         struct autofs_info *ino;
 209
 210         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 211         if (!sbi)
 212                 goto fail_unlock;
 213         DPRINTK("starting up, sbi = %p",sbi);
 214
 215         s->s_fs_info = sbi;
 216         sbi->magic = AUTOFS_SBI_MAGIC;
 217         sbi->pipefd = -1;
 218         sbi->pipe = NULL;
 219         sbi->catatonic = 1;
 220         sbi->exp_timeout = 0;
 221         sbi->oz_pgrp = task_pgrp_nr(current);
 222         sbi->sb = s;
 223         sbi->version = 0;
 224         sbi->sub_version = 0;
 225         set_autofs_type_indirect(&sbi->type);
 226         sbi->min_proto = 0;
 227         sbi->max_proto = 0;
 228         sbi->compat_daemon = is_compat_task();
 229         mutex_init(&sbi->wq_mutex);
 230         mutex_init(&sbi->pipe_mutex);
 231         spin_lock_init(&sbi->fs_lock);
 232         sbi->queues = NULL;
 233         spin_lock_init(&sbi->lookup_lock);
 234         INIT_LIST_HEAD(&sbi->active_list);
 235         INIT_LIST_HEAD(&sbi->expiring_list);
 236         s->s_blocksize = 1024;
 237         s->s_blocksize_bits = 10;
 238         s->s_magic = AUTOFS_SUPER_MAGIC;
 239         s->s_op = &autofs4_sops;
 240         s->s_d_op = &autofs4_dentry_operations;
 241         s->s_time_gran = 1;
 242
 243         /*
 244          * Get the root inode and dentry, but defer checking for errors.
 245          */
 246         ino = autofs4_new_ino(sbi);
 247         if (!ino)
 248                 goto fail_free;
 249         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
 250         root = d_make_root(root_inode);
 251         if (!root)
 252                 goto fail_ino;
 253         pipe = NULL;
 254
 255         root->d_fsdata = ino;
 256
 257         /* Can this call block? */
 258         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 259                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 260                                 &sbi->max_proto)) {
 261                 printk("autofs: called with bogus options\n");
 262                 goto fail_dput;
 263         }
 264
 265         if (autofs_type_trigger(sbi->type))
 266                 __managed_dentry_set_managed(root);
 267
 268         root_inode->i_fop = &autofs4_root_operations;
 269         root_inode->i_op = &autofs4_dir_inode_operations;
 270
 271         /* Couldn't this be tested earlier? */
 272         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 273             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 274                 printk("autofs: kernel does not match daemon version "
 275                        "daemon (%d, %d) kernel (%d, %d)\n",
 276                         sbi->min_proto, sbi->max_proto,
 277                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 278                 goto fail_dput;
 279         }
 280
 281         /* Establish highest kernel protocol version */
 282         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 283                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 284         else
 285                 sbi->version = sbi->max_proto;
 286         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 287
 288         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 289         pipe = fget(pipefd);
 290
 291         if (!pipe) {
 292                 printk("autofs: could not open pipe file descriptor\n");
 293                 goto fail_dput;
 294         }
 295         if (!pipe->f_op || !pipe->f_op->write)
 296                 goto fail_fput;
 297         sbi->pipe = pipe;
 298         sbi->pipefd = pipefd;
 299         sbi->catatonic = 0;
 300
 301         /*
 302          * Success! Install the root dentry now to indicate completion.
 303          */
 304         s->s_root = root;
 305         return 0;
 306
 307         /*
 308          * Failure ... clean up.
 309          */
 310 fail_fput:
 311         printk("autofs: pipe file descriptor does not contain proper ops\n");
 312         fput(pipe);
 313         /* fall through */
 314 fail_dput:
 315         dput(root);
 316         goto fail_free;
 317 fail_ino:
 318         kfree(ino);
 319 fail_free:
 320         kfree(sbi);
 321         s->s_fs_info = NULL;
 322 fail_unlock:
 323         return -EINVAL;
 324 }
 325
 326 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
 327 {
 328         struct inode *inode = new_inode(sb);
 329
 330         if (inode == NULL)
 331                 return NULL;
 332
 333         inode->i_mode = mode;
 334         if (sb->s_root) {
 335                 inode->i_uid = sb->s_root->d_inode->i_uid;
 336                 inode->i_gid = sb->s_root->d_inode->i_gid;
 337         }
 338         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 339         inode->i_ino = get_next_ino();
 340
 341         if (S_ISDIR(mode)) {
 342                 set_nlink(inode, 2);
 343                 inode->i_op = &autofs4_dir_inode_operations;
 344                 inode->i_fop = &autofs4_dir_operations;
 345         } else if (S_ISLNK(mode)) {
 346                 inode->i_op = &autofs4_symlink_inode_operations;
 347         }
 348
 349         return inode;
 350 }