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, 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 = process_group(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
 142         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 143         if ( !sbi )
 144                 goto fail_unlock;
 145         DPRINTK(("autofs: starting up, sbi = %p\n",sbi));
 146
 147         s->s_fs_info = sbi;
 148         sbi->magic = AUTOFS_SBI_MAGIC;
 149         sbi->pipe = NULL;
 150         sbi->catatonic = 1;
 151         sbi->exp_timeout = 0;
 152         sbi->oz_pgrp = process_group(current);
 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 = iget(s, AUTOFS_ROOT_INO);
 165         root = d_alloc_root(root_inode);
 166         pipe = NULL;
 167
 168         if (!root)
 169                 goto fail_iput;
 170
 171         /* Can this call block?  - WTF cares? s is locked. */
 172         if ( parse_options(data,&pipefd,&root_inode->i_uid,&root_inode->i_gid,&sbi->oz_pgrp,&minproto,&maxproto) ) {
 173                 printk("autofs: called with bogus options\n");
 174                 goto fail_dput;
 175         }
 176
 177         /* Couldn't this be tested earlier? */
 178         if ( minproto > AUTOFS_PROTO_VERSION ||
 179              maxproto < AUTOFS_PROTO_VERSION ) {
 180                 printk("autofs: kernel does not match daemon version\n");
 181                 goto fail_dput;
 182         }
 183
 184         DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, sbi->oz_pgrp));
 185         pipe = fget(pipefd);
 186
 187         if ( !pipe ) {
 188                 printk("autofs: could not open pipe file descriptor\n");
 189                 goto fail_dput;
 190         }
 191         if ( !pipe->f_op || !pipe->f_op->write )
 192                 goto fail_fput;
 193         sbi->pipe = pipe;
 194         sbi->catatonic = 0;
 195
 196         /*
 197          * Success! Install the root dentry now to indicate completion.
 198          */
 199         s->s_root = root;
 200         return 0;
 201
 202 fail_fput:
 203         printk("autofs: pipe file descriptor does not contain proper ops\n");
 204         fput(pipe);
 205 fail_dput:
 206         dput(root);
 207         goto fail_free;
 208 fail_iput:
 209         printk("autofs: get root dentry failed\n");
 210         iput(root_inode);
 211 fail_free:
 212         kfree(sbi);
 213         s->s_fs_info = NULL;
 214 fail_unlock:
 215         return -EINVAL;
 216 }
 217
 218 static void autofs_read_inode(struct inode *inode)
 219 {
 220         ino_t ino = inode->i_ino;
 221         unsigned int n;
 222         struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
 223
 224         /* Initialize to the default case (stub directory) */
 225
 226         inode->i_op = &simple_dir_inode_operations;
 227         inode->i_fop = &simple_dir_operations;
 228         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 229         inode->i_nlink = 2;
 230         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 231         inode->i_blocks = 0;
 232
 233         if ( ino == AUTOFS_ROOT_INO ) {
 234                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
 235                 inode->i_op = &autofs_root_inode_operations;
 236                 inode->i_fop = &autofs_root_operations;
 237                 inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
 238                 return;
 239         }
 240
 241         inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
 242         inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
 243
 244         if ( ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO ) {
 245                 /* Symlink inode - should be in symlink list */
 246                 struct autofs_symlink *sl;
 247
 248                 n = ino - AUTOFS_FIRST_SYMLINK;
 249                 if ( n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
 250                         printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
 251                         return;
 252                 }
 253
 254                 inode->i_op = &autofs_symlink_inode_operations;
 255                 sl = &sbi->symlink[n];
 256                 inode->i_private = sl;
 257                 inode->i_mode = S_IFLNK | S_IRWXUGO;
 258                 inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
 259                 inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
 260                 inode->i_size = sl->len;
 261                 inode->i_nlink = 1;
 262         }
 263 }