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 "autofs_i.h"
  23 #include <linux/module.h>
  24
  25 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
  26 {
  27         struct autofs_info *ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  28         if (ino) {
  29                 INIT_LIST_HEAD(&ino->active);
  30                 INIT_LIST_HEAD(&ino->expiring);
  31                 ino->last_used = jiffies;
  32                 ino->sbi = sbi;
  33         }
  34         return ino;
  35 }
  36
  37 void autofs4_clean_ino(struct autofs_info *ino)
  38 {
  39         ino->uid = 0;
  40         ino->gid = 0;
  41         ino->last_used = jiffies;
  42 }
  43
  44 void autofs4_free_ino(struct autofs_info *ino)
  45 {
  46         if (ino->dentry) {
  47                 ino->dentry->d_fsdata = NULL;
  48                 ino->dentry = NULL;
  49         }
  50         kfree(ino);
  51 }
  52
  53 void autofs4_kill_sb(struct super_block *sb)
  54 {
  55         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  56
  57         /*
  58          * In the event of a failure in get_sb_nodev the superblock
  59          * info is not present so nothing else has been setup, so
  60          * just call kill_anon_super when we are called from
  61          * deactivate_super.
  62          */
  63         if (!sbi)
  64                 goto out_kill_sb;
  65
  66         /* Free wait queues, close pipe */
  67         autofs4_catatonic_mode(sbi);
  68
  69         sb->s_fs_info = NULL;
  70         kfree(sbi);
  71
  72 out_kill_sb:
  73         DPRINTK("shutting down");
  74         kill_litter_super(sb);
  75 }
  76
  77 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
  78 {
  79         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
  80         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
  81
  82         if (!sbi)
  83                 return 0;
  84
  85         seq_printf(m, ",fd=%d", sbi->pipefd);
  86         if (root_inode->i_uid != 0)
  87                 seq_printf(m, ",uid=%u", root_inode->i_uid);
  88         if (root_inode->i_gid != 0)
  89                 seq_printf(m, ",gid=%u", root_inode->i_gid);
  90         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
  91         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  92         seq_printf(m, ",minproto=%d", sbi->min_proto);
  93         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  94
  95         if (autofs_type_offset(sbi->type))
  96                 seq_printf(m, ",offset");
  97         else if (autofs_type_direct(sbi->type))
  98                 seq_printf(m, ",direct");
  99         else
 100                 seq_printf(m, ",indirect");
 101
 102         return 0;
 103 }
 104
 105 static void autofs4_evict_inode(struct inode *inode)
 106 {
 107         end_writeback(inode);
 108         kfree(inode->i_private);
 109 }
 110
 111 static const struct super_operations autofs4_sops = {
 112         .statfs         = simple_statfs,
 113         .show_options   = autofs4_show_options,
 114         .evict_inode    = autofs4_evict_inode,
 115 };
 116
 117 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 118         Opt_indirect, Opt_direct, Opt_offset};
 119
 120 static const match_table_t tokens = {
 121         {Opt_fd, "fd=%u"},
 122         {Opt_uid, "uid=%u"},
 123         {Opt_gid, "gid=%u"},
 124         {Opt_pgrp, "pgrp=%u"},
 125         {Opt_minproto, "minproto=%u"},
 126         {Opt_maxproto, "maxproto=%u"},
 127         {Opt_indirect, "indirect"},
 128         {Opt_direct, "direct"},
 129         {Opt_offset, "offset"},
 130         {Opt_err, NULL}
 131 };
 132
 133 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 134                 pid_t *pgrp, unsigned int *type, 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         *pgrp = task_pgrp_nr(current);
 143
 144         *minproto = AUTOFS_MIN_PROTO_VERSION;
 145         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 146
 147         *pipefd = -1;
 148
 149         if (!options)
 150                 return 1;
 151
 152         while ((p = strsep(&options, ",")) != NULL) {
 153                 int token;
 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 = option;
 167                         break;
 168                 case Opt_gid:
 169                         if (match_int(args, &option))
 170                                 return 1;
 171                         *gid = option;
 172                         break;
 173                 case Opt_pgrp:
 174                         if (match_int(args, &option))
 175                                 return 1;
 176                         *pgrp = option;
 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
 213         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 214         if (!sbi)
 215                 goto fail_unlock;
 216         DPRINTK("starting up, sbi = %p",sbi);
 217
 218         s->s_fs_info = sbi;
 219         sbi->magic = AUTOFS_SBI_MAGIC;
 220         sbi->pipefd = -1;
 221         sbi->pipe = NULL;
 222         sbi->catatonic = 1;
 223         sbi->exp_timeout = 0;
 224         sbi->oz_pgrp = task_pgrp_nr(current);
 225         sbi->sb = s;
 226         sbi->version = 0;
 227         sbi->sub_version = 0;
 228         set_autofs_type_indirect(&sbi->type);
 229         sbi->min_proto = 0;
 230         sbi->max_proto = 0;
 231         mutex_init(&sbi->wq_mutex);
 232         spin_lock_init(&sbi->fs_lock);
 233         sbi->queues = NULL;
 234         spin_lock_init(&sbi->lookup_lock);
 235         INIT_LIST_HEAD(&sbi->active_list);
 236         INIT_LIST_HEAD(&sbi->expiring_list);
 237         s->s_blocksize = 1024;
 238         s->s_blocksize_bits = 10;
 239         s->s_magic = AUTOFS_SUPER_MAGIC;
 240         s->s_op = &autofs4_sops;
 241         s->s_d_op = &autofs4_dentry_operations;
 242         s->s_time_gran = 1;
 243
 244         /*
 245          * Get the root inode and dentry, but defer checking for errors.
 246          */
 247         ino = autofs4_new_ino(sbi);
 248         if (!ino)
 249                 goto fail_free;
 250         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
 251         if (!root_inode)
 252                 goto fail_ino;
 253
 254         root = d_alloc_root(root_inode);
 255         if (!root)
 256                 goto fail_iput;
 257         pipe = NULL;
 258
 259         root->d_fsdata = ino;
 260
 261         /* Can this call block? */
 262         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 263                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 264                                 &sbi->max_proto)) {
 265                 printk("autofs: called with bogus options\n");
 266                 goto fail_dput;
 267         }
 268
 269         if (autofs_type_trigger(sbi->type))
 270                 __managed_dentry_set_managed(root);
 271
 272         root_inode->i_fop = &autofs4_root_operations;
 273         root_inode->i_op = &autofs4_dir_inode_operations;
 274
 275         /* Couldn't this be tested earlier? */
 276         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 277             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 278                 printk("autofs: kernel does not match daemon version "
 279                        "daemon (%d, %d) kernel (%d, %d)\n",
 280                         sbi->min_proto, sbi->max_proto,
 281                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 282                 goto fail_dput;
 283         }
 284
 285         /* Establish highest kernel protocol version */
 286         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 287                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 288         else
 289                 sbi->version = sbi->max_proto;
 290         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 291
 292         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 293         pipe = fget(pipefd);
 294
 295         if (!pipe) {
 296                 printk("autofs: could not open pipe file descriptor\n");
 297                 goto fail_dput;
 298         }
 299         if (!pipe->f_op || !pipe->f_op->write)
 300                 goto fail_fput;
 301         sbi->pipe = pipe;
 302         sbi->pipefd = pipefd;
 303         sbi->catatonic = 0;
 304
 305         /*
 306          * Success! Install the root dentry now to indicate completion.
 307          */
 308         s->s_root = root;
 309         return 0;
 310
 311         /*
 312          * Failure ... clean up.
 313          */
 314 fail_fput:
 315         printk("autofs: pipe file descriptor does not contain proper ops\n");
 316         fput(pipe);
 317         /* fall through */
 318 fail_dput:
 319         dput(root);
 320         goto fail_free;
 321 fail_iput:
 322         printk("autofs: get root dentry failed\n");
 323         iput(root_inode);
 324 fail_ino:
 325         kfree(ino);
 326 fail_free:
 327         kfree(sbi);
 328         s->s_fs_info = NULL;
 329 fail_unlock:
 330         return -EINVAL;
 331 }
 332
 333 struct inode *autofs4_get_inode(struct super_block *sb, mode_t mode)
 334 {
 335         struct inode *inode = new_inode(sb);
 336
 337         if (inode == NULL)
 338                 return NULL;
 339
 340         inode->i_mode = mode;
 341         if (sb->s_root) {
 342                 inode->i_uid = sb->s_root->d_inode->i_uid;
 343                 inode->i_gid = sb->s_root->d_inode->i_gid;
 344         }
 345         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 346         inode->i_ino = get_next_ino();
 347
 348         if (S_ISDIR(mode)) {
 349                 inode->i_nlink = 2;
 350                 inode->i_op = &autofs4_dir_inode_operations;
 351                 inode->i_fop = &autofs4_dir_operations;
 352         } else if (S_ISLNK(mode)) {
 353                 inode->i_op = &autofs4_symlink_inode_operations;
 354         }
 355
 356         return inode;
 357 }