kernel/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) {
  60                 /* Free wait queues, close pipe */
  61                 autofs4_catatonic_mode(sbi);
  62                 put_pid(sbi->oz_pgrp);
  63         }
  64
  65         DPRINTK("shutting down");
  66         kill_litter_super(sb);
  67         if (sbi)
  68                 kfree_rcu(sbi, rcu);
  69 }
  70
  71 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
  72 {
  73         struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
  74         struct inode *root_inode = d_inode(root->d_sb->s_root);
  75
  76         if (!sbi)
  77                 return 0;
  78
  79         seq_printf(m, ",fd=%d", sbi->pipefd);
  80         if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  81                 seq_printf(m, ",uid=%u",
  82                         from_kuid_munged(&init_user_ns, root_inode->i_uid));
  83         if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  84                 seq_printf(m, ",gid=%u",
  85                         from_kgid_munged(&init_user_ns, root_inode->i_gid));
  86         seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  87         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  88         seq_printf(m, ",minproto=%d", sbi->min_proto);
  89         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  90
  91         if (autofs_type_offset(sbi->type))
  92                 seq_printf(m, ",offset");
  93         else if (autofs_type_direct(sbi->type))
  94                 seq_printf(m, ",direct");
  95         else
  96                 seq_printf(m, ",indirect");
  97
  98         return 0;
  99 }
 100
 101 static void autofs4_evict_inode(struct inode *inode)
 102 {
 103         clear_inode(inode);
 104         kfree(inode->i_private);
 105 }
 106
 107 static const struct super_operations autofs4_sops = {
 108         .statfs         = simple_statfs,
 109         .show_options   = autofs4_show_options,
 110         .evict_inode    = autofs4_evict_inode,
 111 };
 112
 113 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 114         Opt_indirect, Opt_direct, Opt_offset};
 115
 116 static const match_table_t tokens = {
 117         {Opt_fd, "fd=%u"},
 118         {Opt_uid, "uid=%u"},
 119         {Opt_gid, "gid=%u"},
 120         {Opt_pgrp, "pgrp=%u"},
 121         {Opt_minproto, "minproto=%u"},
 122         {Opt_maxproto, "maxproto=%u"},
 123         {Opt_indirect, "indirect"},
 124         {Opt_direct, "direct"},
 125         {Opt_offset, "offset"},
 126         {Opt_err, NULL}
 127 };
 128
 129 static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
 130                          int *pgrp, bool *pgrp_set, unsigned int *type,
 131                          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
 140         *minproto = AUTOFS_MIN_PROTO_VERSION;
 141         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 142
 143         *pipefd = -1;
 144
 145         if (!options)
 146                 return 1;
 147
 148         while ((p = strsep(&options, ",")) != NULL) {
 149                 int token;
 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 autofs4_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         DPRINTK("starting up, sbi = %p",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 = &autofs4_sops;
 246         s->s_d_op = &autofs4_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 = autofs4_new_ino(sbi);
 253         if (!ino) {
 254                 ret = -ENOMEM;
 255                 goto fail_free;
 256         }
 257         root_inode = autofs4_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                 printk("autofs: called with bogus options\n");
 270                 goto fail_dput;
 271         }
 272
 273         if (pgrp_set) {
 274                 sbi->oz_pgrp = find_get_pid(pgrp);
 275                 if (!sbi->oz_pgrp) {
 276                         pr_warn("autofs: could not find process group %d\n",
 277                                 pgrp);
 278                         goto fail_dput;
 279                 }
 280         } else {
 281                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 282         }
 283
 284         if (autofs_type_trigger(sbi->type))
 285                 __managed_dentry_set_managed(root);
 286
 287         root_inode->i_fop = &autofs4_root_operations;
 288         root_inode->i_op = &autofs4_dir_inode_operations;
 289
 290         /* Couldn't this be tested earlier? */
 291         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 292             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 293                 printk("autofs: kernel does not match daemon version "
 294                        "daemon (%d, %d) kernel (%d, %d)\n",
 295                         sbi->min_proto, sbi->max_proto,
 296                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 297                 goto fail_dput;
 298         }
 299
 300         /* Establish highest kernel protocol version */
 301         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 302                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 303         else
 304                 sbi->version = sbi->max_proto;
 305         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 306
 307         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, pid_nr(sbi->oz_pgrp));
 308         pipe = fget(pipefd);
 309
 310         if (!pipe) {
 311                 printk("autofs: could not open pipe file descriptor\n");
 312                 goto fail_dput;
 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         printk("autofs: pipe file descriptor does not contain proper ops\n");
 332         fput(pipe);
 333         /* fall through */
 334 fail_dput:
 335         dput(root);
 336         goto fail_free;
 337 fail_ino:
 338         kfree(ino);
 339 fail_free:
 340         put_pid(sbi->oz_pgrp);
 341         kfree(sbi);
 342         s->s_fs_info = NULL;
 343         return ret;
 344 }
 345
 346 struct inode *autofs4_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;
 359         inode->i_ino = get_next_ino();
 360
 361         if (S_ISDIR(mode)) {
 362                 set_nlink(inode, 2);
 363                 inode->i_op = &autofs4_dir_inode_operations;
 364                 inode->i_fop = &autofs4_dir_operations;
 365         } else if (S_ISLNK(mode)) {
 366                 inode->i_op = &autofs4_symlink_inode_operations;
 367         }
 368
 369         return inode;
 370 }