fs/autofs/inode.c

   1 /* -*- linux-c -*- --------------------------------------------------------- *
   2  *
   3  * linux/fs/autofs/inode.c
   4  *
   5  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   6  *
   7  * This file is part of the Linux kernel and is made available under
   8  * the terms of the GNU General Public License, version 2, or at your
   9  * option, any later version, incorporated herein by reference.
  10  *
  11  * ------------------------------------------------------------------------- */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/mm.h>
  15 #include <linux/slab.h>
  16 #include <linux/file.h>
  17 #include <linux/parser.h>
  18 #include <linux/bitops.h>
  19 #include <linux/magic.h>
  20 #include "autofs_i.h"
  21 #include <linux/module.h>
  22
  23 void autofs_kill_sb(struct super_block *sb)
  24 {
  25         struct autofs_sb_info *sbi = autofs_sbi(sb);
  26         unsigned int n;
  27
  28         /*
  29          * In the event of a failure in get_sb_nodev the superblock
  30          * info is not present so nothing else has been setup, so
  31          * just call kill_anon_super when we are called from
  32          * deactivate_super.
  33          */
  34         if (!sbi)
  35                 goto out_kill_sb;
  36
  37         if (!sbi->catatonic)
  38                 autofs_catatonic_mode(sbi); /* Free wait queues, close pipe */
  39
  40         put_pid(sbi->oz_pgrp);
  41
  42         autofs_hash_nuke(sbi);
  43         for (n = 0; n < AUTOFS_MAX_SYMLINKS; n++) {
  44                 if (test_bit(n, sbi->symlink_bitmap))
  45                         kfree(sbi->symlink[n].data);
  46         }
  47
  48         kfree(sb->s_fs_info);
  49
  50 out_kill_sb:
  51         DPRINTK(("autofs: shutting down\n"));
  52         kill_anon_super(sb);
  53 }
  54
  55 static const struct super_operations autofs_sops = {
  56         .statfs         = simple_statfs,
  57 };
  58
  59 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
  60
  61 static match_table_t autofs_tokens = {
  62         {Opt_fd, "fd=%u"},
  63         {Opt_uid, "uid=%u"},
  64         {Opt_gid, "gid=%u"},
  65         {Opt_pgrp, "pgrp=%u"},
  66         {Opt_minproto, "minproto=%u"},
  67         {Opt_maxproto, "maxproto=%u"},
  68         {Opt_err, NULL}
  69 };
  70
  71 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
  72                 pid_t *pgrp, int *minproto, int *maxproto)
  73 {
  74         char *p;
  75         substring_t args[MAX_OPT_ARGS];
  76         int option;
  77
  78         *uid = current->uid;
  79         *gid = current->gid;
  80         *pgrp = task_pgrp_nr(current);
  81
  82         *minproto = *maxproto = AUTOFS_PROTO_VERSION;
  83
  84         *pipefd = -1;
  85
  86         if (!options)
  87                 return 1;
  88
  89         while ((p = strsep(&options, ",")) != NULL) {
  90                 int token;
  91                 if (!*p)
  92                         continue;
  93
  94                 token = match_token(p, autofs_tokens, args);
  95                 switch (token) {
  96                 case Opt_fd:
  97                         if (match_int(&args[0], &option))
  98                                 return 1;
  99                         *pipefd = option;
 100                         break;
 101                 case Opt_uid:
 102                         if (match_int(&args[0], &option))
 103                                 return 1;
 104                         *uid = option;
 105                         break;
 106                 case Opt_gid:
 107                         if (match_int(&args[0], &option))
 108                                 return 1;
 109                         *gid = option;
 110                         break;
 111                 case Opt_pgrp:
 112                         if (match_int(&args[0], &option))
 113                                 return 1;
 114                         *pgrp = option;
 115                         break;
 116                 case Opt_minproto:
 117                         if (match_int(&args[0], &option))
 118                                 return 1;
 119                         *minproto = option;
 120                         break;
 121                 case Opt_maxproto:
 122                         if (match_int(&args[0], &option))
 123                                 return 1;
 124                         *maxproto = option;
 125                         break;
 126                 default:
 127                         return 1;
 128                 }
 129         }
 130         return (*pipefd < 0);
 131 }
 132
 133 int autofs_fill_super(struct super_block *s, void *data, int silent)
 134 {
 135         struct inode * root_inode;
 136         struct dentry * root;
 137         struct file * pipe;
 138         int pipefd;
 139         struct autofs_sb_info *sbi;
 140         int minproto, maxproto;
 141         pid_t pgid;
 142
 143         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 144         if (!sbi)
 145                 goto fail_unlock;
 146         DPRINTK(("autofs: starting up, sbi = %p\n",sbi));
 147
 148         s->s_fs_info = sbi;
 149         sbi->magic = AUTOFS_SBI_MAGIC;
 150         sbi->pipe = NULL;
 151         sbi->catatonic = 1;
 152         sbi->exp_timeout = 0;
 153         autofs_initialize_hash(&sbi->dirhash);
 154         sbi->queues = NULL;
 155         memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
 156         sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
 157         s->s_blocksize = 1024;
 158         s->s_blocksize_bits = 10;
 159         s->s_magic = AUTOFS_SUPER_MAGIC;
 160         s->s_op = &autofs_sops;
 161         s->s_time_gran = 1;
 162         sbi->sb = s;
 163
 164         root_inode = autofs_iget(s, AUTOFS_ROOT_INO);
 165         if (IS_ERR(root_inode))
 166                 goto fail_free;
 167         root = d_alloc_root(root_inode);
 168         pipe = NULL;
 169
 170         if (!root)
 171                 goto fail_iput;
 172
 173         /* Can this call block?  - WTF cares? s is locked. */
 174         if (parse_options(data, &pipefd, &root_inode->i_uid,
 175                                 &root_inode->i_gid, &pgid, &minproto,
 176                                 &maxproto)) {
 177                 printk("autofs: called with bogus options\n");
 178                 goto fail_dput;
 179         }
 180
 181         /* Couldn't this be tested earlier? */
 182         if (minproto > AUTOFS_PROTO_VERSION ||
 183              maxproto < AUTOFS_PROTO_VERSION) {
 184                 printk("autofs: kernel does not match daemon version\n");
 185                 goto fail_dput;
 186         }
 187
 188         DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, pgid));
 189         sbi->oz_pgrp = find_get_pid(pgid);
 190
 191         if (!sbi->oz_pgrp) {
 192                 printk("autofs: could not find process group %d\n", pgid);
 193                 goto fail_dput;
 194         }
 195
 196         pipe = fget(pipefd);
 197
 198         if (!pipe) {
 199                 printk("autofs: could not open pipe file descriptor\n");
 200                 goto fail_put_pid;
 201         }
 202
 203         if (!pipe->f_op || !pipe->f_op->write)
 204                 goto fail_fput;
 205         sbi->pipe = pipe;
 206         sbi->catatonic = 0;
 207
 208         /*
 209          * Success! Install the root dentry now to indicate completion.
 210          */
 211         s->s_root = root;
 212         return 0;
 213
 214 fail_fput:
 215         printk("autofs: pipe file descriptor does not contain proper ops\n");
 216         fput(pipe);
 217 fail_put_pid:
 218         put_pid(sbi->oz_pgrp);
 219 fail_dput:
 220         dput(root);
 221         goto fail_free;
 222 fail_iput:
 223         printk("autofs: get root dentry failed\n");
 224         iput(root_inode);
 225 fail_free:
 226         kfree(sbi);
 227         s->s_fs_info = NULL;
 228 fail_unlock:
 229         return -EINVAL;
 230 }
 231
 232 struct inode *autofs_iget(struct super_block *sb, unsigned long ino)
 233 {
 234         unsigned int n;
 235         struct autofs_sb_info *sbi = autofs_sbi(sb);
 236         struct inode *inode;
 237
 238         inode = iget_locked(sb, ino);
 239         if (!inode)
 240                 return ERR_PTR(-ENOMEM);
 241         if (!(inode->i_state & I_NEW))
 242                 return inode;
 243
 244         /* Initialize to the default case (stub directory) */
 245
 246         inode->i_op = &simple_dir_inode_operations;
 247         inode->i_fop = &simple_dir_operations;
 248         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 249         inode->i_nlink = 2;
 250         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 251         inode->i_blocks = 0;
 252
 253         if (ino == AUTOFS_ROOT_INO) {
 254                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
 255                 inode->i_op = &autofs_root_inode_operations;
 256                 inode->i_fop = &autofs_root_operations;
 257                 inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
 258                 goto done;
 259         }
 260
 261         inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
 262         inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
 263
 264         if (ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO) {
 265                 /* Symlink inode - should be in symlink list */
 266                 struct autofs_symlink *sl;
 267
 268                 n = ino - AUTOFS_FIRST_SYMLINK;
 269                 if (n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
 270                         printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
 271                         goto done;
 272                 }
 273
 274                 inode->i_op = &autofs_symlink_inode_operations;
 275                 sl = &sbi->symlink[n];
 276                 inode->i_private = sl;
 277                 inode->i_mode = S_IFLNK | S_IRWXUGO;
 278                 inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
 279                 inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
 280                 inode->i_size = sl->len;
 281                 inode->i_nlink = 1;
 282         }
 283
 284 done:
 285         unlock_new_inode(inode);
 286         return inode;
 287 }