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 = GLOBAL_ROOT_UID;
  40         ino->gid = GLOBAL_ROOT_GID;
  41         ino->last_used = jiffies;
  42 }
  43
  44 void autofs4_free_ino(struct autofs_info *ino)
  45 {
  46         kfree(ino);
  47 }
  48
  49 void autofs4_kill_sb(struct super_block *sb)
  50 {
  51         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  52
  53         /*
  54          * In the event of a failure in get_sb_nodev the superblock
  55          * info is not present so nothing else has been setup, so
  56          * just call kill_anon_super when we are called from
  57          * deactivate_super.
  58          */
  59         if (sbi) /* Free wait queues, close pipe */
  60                 autofs4_catatonic_mode(sbi);
  61
  62         DPRINTK("shutting down");
  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 = root->d_sb->s_root->d_inode;
  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", 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
  95         return 0;
  96 }
  97
  98 static void autofs4_evict_inode(struct inode *inode)
  99 {
 100         clear_inode(inode);
 101         kfree(inode->i_private);
 102 }
 103
 104 static const struct super_operations autofs4_sops = {
 105         .statfs         = simple_statfs,
 106         .show_options   = autofs4_show_options,
 107         .evict_inode    = autofs4_evict_inode,
 108 };
 109
 110 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 111         Opt_indirect, Opt_direct, Opt_offset};
 112
 113 static const match_table_t tokens = {
 114         {Opt_fd, "fd=%u"},
 115         {Opt_uid, "uid=%u"},
 116         {Opt_gid, "gid=%u"},
 117         {Opt_pgrp, "pgrp=%u"},
 118         {Opt_minproto, "minproto=%u"},
 119         {Opt_maxproto, "maxproto=%u"},
 120         {Opt_indirect, "indirect"},
 121         {Opt_direct, "direct"},
 122         {Opt_offset, "offset"},
 123         {Opt_err, NULL}
 124 };
 125
 126 static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
 127                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 128 {
 129         char *p;
 130         substring_t args[MAX_OPT_ARGS];
 131         int option;
 132
 133         *uid = current_uid();
 134         *gid = current_gid();
 135         *pgrp = task_pgrp_nr(current);
 136
 137         *minproto = AUTOFS_MIN_PROTO_VERSION;
 138         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 139
 140         *pipefd = -1;
 141
 142         if (!options)
 143                 return 1;
 144
 145         while ((p = strsep(&options, ",")) != NULL) {
 146                 int token;
 147                 if (!*p)
 148                         continue;
 149
 150                 token = match_token(p, tokens, args);
 151                 switch (token) {
 152                 case Opt_fd:
 153                         if (match_int(args, pipefd))
 154                                 return 1;
 155                         break;
 156                 case Opt_uid:
 157                         if (match_int(args, &option))
 158                                 return 1;
 159                         *uid = make_kuid(current_user_ns(), option);
 160                         if (!uid_valid(*uid))
 161                                 return 1;
 162                         break;
 163                 case Opt_gid:
 164                         if (match_int(args, &option))
 165                                 return 1;
 166                         *gid = make_kgid(current_user_ns(), option);
 167                         if (!gid_valid(*gid))
 168                                 return 1;
 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         mutex_init(&sbi->wq_mutex);
 229         mutex_init(&sbi->pipe_mutex);
 230         spin_lock_init(&sbi->fs_lock);
 231         sbi->queues = NULL;
 232         spin_lock_init(&sbi->lookup_lock);
 233         INIT_LIST_HEAD(&sbi->active_list);
 234         INIT_LIST_HEAD(&sbi->expiring_list);
 235         s->s_blocksize = 1024;
 236         s->s_blocksize_bits = 10;
 237         s->s_magic = AUTOFS_SUPER_MAGIC;
 238         s->s_op = &autofs4_sops;
 239         s->s_d_op = &autofs4_dentry_operations;
 240         s->s_time_gran = 1;
 241
 242         /*
 243          * Get the root inode and dentry, but defer checking for errors.
 244          */
 245         ino = autofs4_new_ino(sbi);
 246         if (!ino)
 247                 goto fail_free;
 248         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
 249         root = d_make_root(root_inode);
 250         if (!root)
 251                 goto fail_ino;
 252         pipe = NULL;
 253
 254         root->d_fsdata = ino;
 255
 256         /* Can this call block? */
 257         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 258                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 259                                 &sbi->max_proto)) {
 260                 printk("autofs: called with bogus options\n");
 261                 goto fail_dput;
 262         }
 263
 264         if (autofs_type_trigger(sbi->type))
 265                 __managed_dentry_set_managed(root);
 266
 267         root_inode->i_fop = &autofs4_root_operations;
 268         root_inode->i_op = &autofs4_dir_inode_operations;
 269
 270         /* Couldn't this be tested earlier? */
 271         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 272             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 273                 printk("autofs: kernel does not match daemon version "
 274                        "daemon (%d, %d) kernel (%d, %d)\n",
 275                         sbi->min_proto, sbi->max_proto,
 276                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 277                 goto fail_dput;
 278         }
 279
 280         /* Establish highest kernel protocol version */
 281         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 282                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 283         else
 284                 sbi->version = sbi->max_proto;
 285         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 286
 287         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 288         pipe = fget(pipefd);
 289
 290         if (!pipe) {
 291                 printk("autofs: could not open pipe file descriptor\n");
 292                 goto fail_dput;
 293         }
 294         if (autofs_prepare_pipe(pipe) < 0)
 295                 goto fail_fput;
 296         sbi->pipe = pipe;
 297         sbi->pipefd = pipefd;
 298         sbi->catatonic = 0;
 299
 300         /*
 301          * Success! Install the root dentry now to indicate completion.
 302          */
 303         s->s_root = root;
 304         return 0;
 305
 306         /*
 307          * Failure ... clean up.
 308          */
 309 fail_fput:
 310         printk("autofs: pipe file descriptor does not contain proper ops\n");
 311         fput(pipe);
 312         /* fall through */
 313 fail_dput:
 314         dput(root);
 315         goto fail_free;
 316 fail_ino:
 317         kfree(ino);
 318 fail_free:
 319         kfree(sbi);
 320         s->s_fs_info = NULL;
 321 fail_unlock:
 322         return -EINVAL;
 323 }
 324
 325 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
 326 {
 327         struct inode *inode = new_inode(sb);
 328
 329         if (inode == NULL)
 330                 return NULL;
 331
 332         inode->i_mode = mode;
 333         if (sb->s_root) {
 334                 inode->i_uid = sb->s_root->d_inode->i_uid;
 335                 inode->i_gid = sb->s_root->d_inode->i_gid;
 336         }
 337         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 338         inode->i_ino = get_next_ino();
 339
 340         if (S_ISDIR(mode)) {
 341                 set_nlink(inode, 2);
 342                 inode->i_op = &autofs4_dir_inode_operations;
 343                 inode->i_fop = &autofs4_dir_operations;
 344         } else if (S_ISLNK(mode)) {
 345                 inode->i_op = &autofs4_symlink_inode_operations;
 346         }
 347
 348         return inode;
 349 }