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 exit when we are called from deactivate_super.
  32          */
  33         if (!sbi)
  34                 return;
  35
  36         if ( !sbi->catatonic )
  37                 autofs_catatonic_mode(sbi); /* Free wait queues, close pipe */
  38
  39         autofs_hash_nuke(sbi);
  40         for ( n = 0 ; n < AUTOFS_MAX_SYMLINKS ; n++ ) {
  41                 if ( test_bit(n, sbi->symlink_bitmap) )
  42                         kfree(sbi->symlink[n].data);
  43         }
  44
  45         kfree(sb->s_fs_info);
  46
  47         DPRINTK(("autofs: shutting down\n"));
  48         kill_anon_super(sb);
  49 }
  50
  51 static void autofs_read_inode(struct inode *inode);
  52
  53 static struct super_operations autofs_sops = {
  54         .read_inode     = autofs_read_inode,
  55         .statfs         = simple_statfs,
  56 };
  57
  58 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
  59
  60 static match_table_t autofs_tokens = {
  61         {Opt_fd, "fd=%u"},
  62         {Opt_uid, "uid=%u"},
  63         {Opt_gid, "gid=%u"},
  64         {Opt_pgrp, "pgrp=%u"},
  65         {Opt_minproto, "minproto=%u"},
  66         {Opt_maxproto, "maxproto=%u"},
  67         {Opt_err, NULL}
  68 };
  69
  70 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid, pid_t *pgrp, int *minproto, int *maxproto)
  71 {
  72         char *p;
  73         substring_t args[MAX_OPT_ARGS];
  74         int option;
  75
  76         *uid = current->uid;
  77         *gid = current->gid;
  78         *pgrp = process_group(current);
  79
  80         *minproto = *maxproto = AUTOFS_PROTO_VERSION;
  81
  82         *pipefd = -1;
  83
  84         if (!options)
  85                 return 1;
  86
  87         while ((p = strsep(&options, ",")) != NULL) {
  88                 int token;
  89                 if (!*p)
  90                         continue;
  91
  92                 token = match_token(p, autofs_tokens, args);
  93                 switch (token) {
  94                 case Opt_fd:
  95                         if (match_int(&args[0], &option))
  96                                 return 1;
  97                         *pipefd = option;
  98                         break;
  99                 case Opt_uid:
 100                         if (match_int(&args[0], &option))
 101                                 return 1;
 102                         *uid = option;
 103                         break;
 104                 case Opt_gid:
 105                         if (match_int(&args[0], &option))
 106                                 return 1;
 107                         *gid = option;
 108                         break;
 109                 case Opt_pgrp:
 110                         if (match_int(&args[0], &option))
 111                                 return 1;
 112                         *pgrp = option;
 113                         break;
 114                 case Opt_minproto:
 115                         if (match_int(&args[0], &option))
 116                                 return 1;
 117                         *minproto = option;
 118                         break;
 119                 case Opt_maxproto:
 120                         if (match_int(&args[0], &option))
 121                                 return 1;
 122                         *maxproto = option;
 123                         break;
 124                 default:
 125                         return 1;
 126                 }
 127         }
 128         return (*pipefd < 0);
 129 }
 130
 131 int autofs_fill_super(struct super_block *s, void *data, int silent)
 132 {
 133         struct inode * root_inode;
 134         struct dentry * root;
 135         struct file * pipe;
 136         int pipefd;
 137         struct autofs_sb_info *sbi;
 138         int minproto, maxproto;
 139
 140         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 141         if ( !sbi )
 142                 goto fail_unlock;
 143         DPRINTK(("autofs: starting up, sbi = %p\n",sbi));
 144
 145         s->s_fs_info = sbi;
 146         sbi->magic = AUTOFS_SBI_MAGIC;
 147         sbi->pipe = NULL;
 148         sbi->catatonic = 1;
 149         sbi->exp_timeout = 0;
 150         sbi->oz_pgrp = process_group(current);
 151         autofs_initialize_hash(&sbi->dirhash);
 152         sbi->queues = NULL;
 153         memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
 154         sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
 155         s->s_blocksize = 1024;
 156         s->s_blocksize_bits = 10;
 157         s->s_magic = AUTOFS_SUPER_MAGIC;
 158         s->s_op = &autofs_sops;
 159         s->s_time_gran = 1;
 160         sbi->sb = s;
 161
 162         root_inode = iget(s, AUTOFS_ROOT_INO);
 163         root = d_alloc_root(root_inode);
 164         pipe = NULL;
 165
 166         if (!root)
 167                 goto fail_iput;
 168
 169         /* Can this call block?  - WTF cares? s is locked. */
 170         if ( parse_options(data,&pipefd,&root_inode->i_uid,&root_inode->i_gid,&sbi->oz_pgrp,&minproto,&maxproto) ) {
 171                 printk("autofs: called with bogus options\n");
 172                 goto fail_dput;
 173         }
 174
 175         /* Couldn't this be tested earlier? */
 176         if ( minproto > AUTOFS_PROTO_VERSION ||
 177              maxproto < AUTOFS_PROTO_VERSION ) {
 178                 printk("autofs: kernel does not match daemon version\n");
 179                 goto fail_dput;
 180         }
 181
 182         DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, sbi->oz_pgrp));
 183         pipe = fget(pipefd);
 184
 185         if ( !pipe ) {
 186                 printk("autofs: could not open pipe file descriptor\n");
 187                 goto fail_dput;
 188         }
 189         if ( !pipe->f_op || !pipe->f_op->write )
 190                 goto fail_fput;
 191         sbi->pipe = pipe;
 192         sbi->catatonic = 0;
 193
 194         /*
 195          * Success! Install the root dentry now to indicate completion.
 196          */
 197         s->s_root = root;
 198         return 0;
 199
 200 fail_fput:
 201         printk("autofs: pipe file descriptor does not contain proper ops\n");
 202         fput(pipe);
 203 fail_dput:
 204         dput(root);
 205         goto fail_free;
 206 fail_iput:
 207         printk("autofs: get root dentry failed\n");
 208         iput(root_inode);
 209 fail_free:
 210         kfree(sbi);
 211         s->s_fs_info = NULL;
 212         kill_anon_super(s);
 213 fail_unlock:
 214         return -EINVAL;
 215 }
 216
 217 static void autofs_read_inode(struct inode *inode)
 218 {
 219         ino_t ino = inode->i_ino;
 220         unsigned int n;
 221         struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
 222
 223         /* Initialize to the default case (stub directory) */
 224
 225         inode->i_op = &simple_dir_inode_operations;
 226         inode->i_fop = &simple_dir_operations;
 227         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 228         inode->i_nlink = 2;
 229         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 230         inode->i_blocks = 0;
 231
 232         if ( ino == AUTOFS_ROOT_INO ) {
 233                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
 234                 inode->i_op = &autofs_root_inode_operations;
 235                 inode->i_fop = &autofs_root_operations;
 236                 inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
 237                 return;
 238         }
 239
 240         inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
 241         inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
 242
 243         if ( ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO ) {
 244                 /* Symlink inode - should be in symlink list */
 245                 struct autofs_symlink *sl;
 246
 247                 n = ino - AUTOFS_FIRST_SYMLINK;
 248                 if ( n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
 249                         printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
 250                         return;
 251                 }
 252
 253                 inode->i_op = &autofs_symlink_inode_operations;
 254                 sl = &sbi->symlink[n];
 255                 inode->i_private = sl;
 256                 inode->i_mode = S_IFLNK | S_IRWXUGO;
 257                 inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
 258                 inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
 259                 inode->i_size = sl->len;
 260                 inode->i_nlink = 1;
 261         }
 262 }