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         autofs_hash_nuke(sbi);
  41         for (n = 0; n < AUTOFS_MAX_SYMLINKS; n++) {
  42                 if (test_bit(n, sbi->symlink_bitmap))
  43                         kfree(sbi->symlink[n].data);
  44         }
  45
  46         kfree(sb->s_fs_info);
  47
  48 out_kill_sb:
  49         DPRINTK(("autofs: shutting down\n"));
  50         kill_anon_super(sb);
  51 }
  52
  53 static void autofs_read_inode(struct inode *inode);
  54
  55 static const struct super_operations autofs_sops = {
  56         .read_inode     = autofs_read_inode,
  57         .statfs         = simple_statfs,
  58 };
  59
  60 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
  61
  62 static match_table_t autofs_tokens = {
  63         {Opt_fd, "fd=%u"},
  64         {Opt_uid, "uid=%u"},
  65         {Opt_gid, "gid=%u"},
  66         {Opt_pgrp, "pgrp=%u"},
  67         {Opt_minproto, "minproto=%u"},
  68         {Opt_maxproto, "maxproto=%u"},
  69         {Opt_err, NULL}
  70 };
  71
  72 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
  73                 pid_t *pgrp, int *minproto, int *maxproto)
  74 {
  75         char *p;
  76         substring_t args[MAX_OPT_ARGS];
  77         int option;
  78
  79         *uid = current->uid;
  80         *gid = current->gid;
  81         *pgrp = process_group(current);
  82
  83         *minproto = *maxproto = AUTOFS_PROTO_VERSION;
  84
  85         *pipefd = -1;
  86
  87         if (!options)
  88                 return 1;
  89
  90         while ((p = strsep(&options, ",")) != NULL) {
  91                 int token;
  92                 if (!*p)
  93                         continue;
  94
  95                 token = match_token(p, autofs_tokens, args);
  96                 switch (token) {
  97                 case Opt_fd:
  98                         if (match_int(&args[0], &option))
  99                                 return 1;
 100                         *pipefd = option;
 101                         break;
 102                 case Opt_uid:
 103                         if (match_int(&args[0], &option))
 104                                 return 1;
 105                         *uid = option;
 106                         break;
 107                 case Opt_gid:
 108                         if (match_int(&args[0], &option))
 109                                 return 1;
 110                         *gid = option;
 111                         break;
 112                 case Opt_pgrp:
 113                         if (match_int(&args[0], &option))
 114                                 return 1;
 115                         *pgrp = option;
 116                         break;
 117                 case Opt_minproto:
 118                         if (match_int(&args[0], &option))
 119                                 return 1;
 120                         *minproto = option;
 121                         break;
 122                 case Opt_maxproto:
 123                         if (match_int(&args[0], &option))
 124                                 return 1;
 125                         *maxproto = option;
 126                         break;
 127                 default:
 128                         return 1;
 129                 }
 130         }
 131         return (*pipefd < 0);
 132 }
 133
 134 int autofs_fill_super(struct super_block *s, void *data, int silent)
 135 {
 136         struct inode * root_inode;
 137         struct dentry * root;
 138         struct file * pipe;
 139         int pipefd;
 140         struct autofs_sb_info *sbi;
 141         int minproto, maxproto;
 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         sbi->oz_pgrp = process_group(current);
 154         autofs_initialize_hash(&sbi->dirhash);
 155         sbi->queues = NULL;
 156         memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
 157         sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
 158         s->s_blocksize = 1024;
 159         s->s_blocksize_bits = 10;
 160         s->s_magic = AUTOFS_SUPER_MAGIC;
 161         s->s_op = &autofs_sops;
 162         s->s_time_gran = 1;
 163         sbi->sb = s;
 164
 165         root_inode = iget(s, AUTOFS_ROOT_INO);
 166         root = d_alloc_root(root_inode);
 167         pipe = NULL;
 168
 169         if (!root)
 170                 goto fail_iput;
 171
 172         /* Can this call block?  - WTF cares? s is locked. */
 173         if (parse_options(data, &pipefd, &root_inode->i_uid,
 174                                 &root_inode->i_gid, &sbi->oz_pgrp, &minproto,
 175                                 &maxproto)) {
 176                 printk("autofs: called with bogus options\n");
 177                 goto fail_dput;
 178         }
 179
 180         /* Couldn't this be tested earlier? */
 181         if (minproto > AUTOFS_PROTO_VERSION ||
 182              maxproto < AUTOFS_PROTO_VERSION) {
 183                 printk("autofs: kernel does not match daemon version\n");
 184                 goto fail_dput;
 185         }
 186
 187         DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, sbi->oz_pgrp));
 188         pipe = fget(pipefd);
 189
 190         if (!pipe) {
 191                 printk("autofs: could not open pipe file descriptor\n");
 192                 goto fail_dput;
 193         }
 194         if (!pipe->f_op || !pipe->f_op->write)
 195                 goto fail_fput;
 196         sbi->pipe = pipe;
 197         sbi->catatonic = 0;
 198
 199         /*
 200          * Success! Install the root dentry now to indicate completion.
 201          */
 202         s->s_root = root;
 203         return 0;
 204
 205 fail_fput:
 206         printk("autofs: pipe file descriptor does not contain proper ops\n");
 207         fput(pipe);
 208 fail_dput:
 209         dput(root);
 210         goto fail_free;
 211 fail_iput:
 212         printk("autofs: get root dentry failed\n");
 213         iput(root_inode);
 214 fail_free:
 215         kfree(sbi);
 216         s->s_fs_info = NULL;
 217 fail_unlock:
 218         return -EINVAL;
 219 }
 220
 221 static void autofs_read_inode(struct inode *inode)
 222 {
 223         ino_t ino = inode->i_ino;
 224         unsigned int n;
 225         struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
 226
 227         /* Initialize to the default case (stub directory) */
 228
 229         inode->i_op = &simple_dir_inode_operations;
 230         inode->i_fop = &simple_dir_operations;
 231         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 232         inode->i_nlink = 2;
 233         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 234         inode->i_blocks = 0;
 235
 236         if (ino == AUTOFS_ROOT_INO) {
 237                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
 238                 inode->i_op = &autofs_root_inode_operations;
 239                 inode->i_fop = &autofs_root_operations;
 240                 inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
 241                 return;
 242         }
 243
 244         inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
 245         inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
 246
 247         if (ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO) {
 248                 /* Symlink inode - should be in symlink list */
 249                 struct autofs_symlink *sl;
 250
 251                 n = ino - AUTOFS_FIRST_SYMLINK;
 252                 if (n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
 253                         printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
 254                         return;
 255                 }
 256
 257                 inode->i_op = &autofs_symlink_inode_operations;
 258                 sl = &sbi->symlink[n];
 259                 inode->i_private = sl;
 260                 inode->i_mode = S_IFLNK | S_IRWXUGO;
 261                 inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
 262                 inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
 263                 inode->i_size = sl->len;
 264                 inode->i_nlink = 1;
 265         }
 266 }