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 void autofs_read_inode(struct inode *inode);
  56
  57 static const struct super_operations autofs_sops = {
  58         .read_inode     = autofs_read_inode,
  59         .statfs         = simple_statfs,
  60 };
  61
  62 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
  63
  64 static match_table_t autofs_tokens = {
  65         {Opt_fd, "fd=%u"},
  66         {Opt_uid, "uid=%u"},
  67         {Opt_gid, "gid=%u"},
  68         {Opt_pgrp, "pgrp=%u"},
  69         {Opt_minproto, "minproto=%u"},
  70         {Opt_maxproto, "maxproto=%u"},
  71         {Opt_err, NULL}
  72 };
  73
  74 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
  75                 pid_t *pgrp, int *minproto, int *maxproto)
  76 {
  77         char *p;
  78         substring_t args[MAX_OPT_ARGS];
  79         int option;
  80
  81         *uid = current->uid;
  82         *gid = current->gid;
  83         *pgrp = task_pgrp_nr(current);
  84
  85         *minproto = *maxproto = AUTOFS_PROTO_VERSION;
  86
  87         *pipefd = -1;
  88
  89         if (!options)
  90                 return 1;
  91
  92         while ((p = strsep(&options, ",")) != NULL) {
  93                 int token;
  94                 if (!*p)
  95                         continue;
  96
  97                 token = match_token(p, autofs_tokens, args);
  98                 switch (token) {
  99                 case Opt_fd:
 100                         if (match_int(&args[0], &option))
 101                                 return 1;
 102                         *pipefd = option;
 103                         break;
 104                 case Opt_uid:
 105                         if (match_int(&args[0], &option))
 106                                 return 1;
 107                         *uid = option;
 108                         break;
 109                 case Opt_gid:
 110                         if (match_int(&args[0], &option))
 111                                 return 1;
 112                         *gid = option;
 113                         break;
 114                 case Opt_pgrp:
 115                         if (match_int(&args[0], &option))
 116                                 return 1;
 117                         *pgrp = option;
 118                         break;
 119                 case Opt_minproto:
 120                         if (match_int(&args[0], &option))
 121                                 return 1;
 122                         *minproto = option;
 123                         break;
 124                 case Opt_maxproto:
 125                         if (match_int(&args[0], &option))
 126                                 return 1;
 127                         *maxproto = option;
 128                         break;
 129                 default:
 130                         return 1;
 131                 }
 132         }
 133         return (*pipefd < 0);
 134 }
 135
 136 int autofs_fill_super(struct super_block *s, void *data, int silent)
 137 {
 138         struct inode * root_inode;
 139         struct dentry * root;
 140         struct file * pipe;
 141         int pipefd;
 142         struct autofs_sb_info *sbi;
 143         int minproto, maxproto;
 144         pid_t pgid;
 145
 146         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 147         if (!sbi)
 148                 goto fail_unlock;
 149         DPRINTK(("autofs: starting up, sbi = %p\n",sbi));
 150
 151         s->s_fs_info = sbi;
 152         sbi->magic = AUTOFS_SBI_MAGIC;
 153         sbi->pipe = NULL;
 154         sbi->catatonic = 1;
 155         sbi->exp_timeout = 0;
 156         autofs_initialize_hash(&sbi->dirhash);
 157         sbi->queues = NULL;
 158         memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
 159         sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
 160         s->s_blocksize = 1024;
 161         s->s_blocksize_bits = 10;
 162         s->s_magic = AUTOFS_SUPER_MAGIC;
 163         s->s_op = &autofs_sops;
 164         s->s_time_gran = 1;
 165         sbi->sb = s;
 166
 167         root_inode = iget(s, AUTOFS_ROOT_INO);
 168         root = d_alloc_root(root_inode);
 169         pipe = NULL;
 170
 171         if (!root)
 172                 goto fail_iput;
 173
 174         /* Can this call block?  - WTF cares? s is locked. */
 175         if (parse_options(data, &pipefd, &root_inode->i_uid,
 176                                 &root_inode->i_gid, &pgid, &minproto,
 177                                 &maxproto)) {
 178                 printk("autofs: called with bogus options\n");
 179                 goto fail_dput;
 180         }
 181
 182         /* Couldn't this be tested earlier? */
 183         if (minproto > AUTOFS_PROTO_VERSION ||
 184              maxproto < AUTOFS_PROTO_VERSION) {
 185                 printk("autofs: kernel does not match daemon version\n");
 186                 goto fail_dput;
 187         }
 188
 189         DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, pgid));
 190         sbi->oz_pgrp = find_get_pid(pgid);
 191
 192         if (!sbi->oz_pgrp) {
 193                 printk("autofs: could not find process group %d\n", pgid);
 194                 goto fail_dput;
 195         }
 196
 197         pipe = fget(pipefd);
 198
 199         if (!pipe) {
 200                 printk("autofs: could not open pipe file descriptor\n");
 201                 goto fail_put_pid;
 202         }
 203
 204         if (!pipe->f_op || !pipe->f_op->write)
 205                 goto fail_fput;
 206         sbi->pipe = pipe;
 207         sbi->catatonic = 0;
 208
 209         /*
 210          * Success! Install the root dentry now to indicate completion.
 211          */
 212         s->s_root = root;
 213         return 0;
 214
 215 fail_fput:
 216         printk("autofs: pipe file descriptor does not contain proper ops\n");
 217         fput(pipe);
 218 fail_put_pid:
 219         put_pid(sbi->oz_pgrp);
 220 fail_dput:
 221         dput(root);
 222         goto fail_free;
 223 fail_iput:
 224         printk("autofs: get root dentry failed\n");
 225         iput(root_inode);
 226 fail_free:
 227         kfree(sbi);
 228         s->s_fs_info = NULL;
 229 fail_unlock:
 230         return -EINVAL;
 231 }
 232
 233 static void autofs_read_inode(struct inode *inode)
 234 {
 235         ino_t ino = inode->i_ino;
 236         unsigned int n;
 237         struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
 238
 239         /* Initialize to the default case (stub directory) */
 240
 241         inode->i_op = &simple_dir_inode_operations;
 242         inode->i_fop = &simple_dir_operations;
 243         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 244         inode->i_nlink = 2;
 245         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 246         inode->i_blocks = 0;
 247
 248         if (ino == AUTOFS_ROOT_INO) {
 249                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
 250                 inode->i_op = &autofs_root_inode_operations;
 251                 inode->i_fop = &autofs_root_operations;
 252                 inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
 253                 return;
 254         }
 255
 256         inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
 257         inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
 258
 259         if (ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO) {
 260                 /* Symlink inode - should be in symlink list */
 261                 struct autofs_symlink *sl;
 262
 263                 n = ino - AUTOFS_FIRST_SYMLINK;
 264                 if (n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
 265                         printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
 266                         return;
 267                 }
 268
 269                 inode->i_op = &autofs_symlink_inode_operations;
 270                 sl = &sbi->symlink[n];
 271                 inode->i_private = sl;
 272                 inode->i_mode = S_IFLNK | S_IRWXUGO;
 273                 inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
 274                 inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
 275                 inode->i_size = sl->len;
 276                 inode->i_nlink = 1;
 277         }
 278 }