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 "autofs_i.h"
  20 #include <linux/module.h>
  21
  22 static void autofs_put_super(struct super_block *sb)
  23 {
  24         struct autofs_sb_info *sbi = autofs_sbi(sb);
  25         unsigned int n;
  26
  27         if ( !sbi->catatonic )
  28                 autofs_catatonic_mode(sbi); /* Free wait queues, close pipe */
  29
  30         autofs_hash_nuke(sbi);
  31         for ( n = 0 ; n < AUTOFS_MAX_SYMLINKS ; n++ ) {
  32                 if ( test_bit(n, sbi->symlink_bitmap) )
  33                         kfree(sbi->symlink[n].data);
  34         }
  35
  36         kfree(sb->s_fs_info);
  37
  38         DPRINTK(("autofs: shutting down\n"));
  39 }
  40
  41 static void autofs_read_inode(struct inode *inode);
  42
  43 static struct super_operations autofs_sops = {
  44         .read_inode     = autofs_read_inode,
  45         .put_super      = autofs_put_super,
  46         .statfs         = simple_statfs,
  47 };
  48
  49 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
  50
  51 static match_table_t autofs_tokens = {
  52         {Opt_fd, "fd=%u"},
  53         {Opt_uid, "uid=%u"},
  54         {Opt_gid, "gid=%u"},
  55         {Opt_pgrp, "pgrp=%u"},
  56         {Opt_minproto, "minproto=%u"},
  57         {Opt_maxproto, "maxproto=%u"},
  58         {Opt_err, NULL}
  59 };
  60
  61 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid, pid_t *pgrp, int *minproto, int *maxproto)
  62 {
  63         char *p;
  64         substring_t args[MAX_OPT_ARGS];
  65         int option;
  66
  67         *uid = current->uid;
  68         *gid = current->gid;
  69         *pgrp = process_group(current);
  70
  71         *minproto = *maxproto = AUTOFS_PROTO_VERSION;
  72
  73         *pipefd = -1;
  74
  75         if (!options)
  76                 return 1;
  77
  78         while ((p = strsep(&options, ",")) != NULL) {
  79                 int token;
  80                 if (!*p)
  81                         continue;
  82
  83                 token = match_token(p, autofs_tokens, args);
  84                 switch (token) {
  85                 case Opt_fd:
  86                         if (match_int(&args[0], &option))
  87                                 return 1;
  88                         *pipefd = option;
  89                         break;
  90                 case Opt_uid:
  91                         if (match_int(&args[0], &option))
  92                                 return 1;
  93                         *uid = option;
  94                         break;
  95                 case Opt_gid:
  96                         if (match_int(&args[0], &option))
  97                                 return 1;
  98                         *gid = option;
  99                         break;
 100                 case Opt_pgrp:
 101                         if (match_int(&args[0], &option))
 102                                 return 1;
 103                         *pgrp = option;
 104                         break;
 105                 case Opt_minproto:
 106                         if (match_int(&args[0], &option))
 107                                 return 1;
 108                         *minproto = option;
 109                         break;
 110                 case Opt_maxproto:
 111                         if (match_int(&args[0], &option))
 112                                 return 1;
 113                         *maxproto = option;
 114                         break;
 115                 default:
 116                         return 1;
 117                 }
 118         }
 119         return (*pipefd < 0);
 120 }
 121
 122 int autofs_fill_super(struct super_block *s, void *data, int silent)
 123 {
 124         struct inode * root_inode;
 125         struct dentry * root;
 126         struct file * pipe;
 127         int pipefd;
 128         struct autofs_sb_info *sbi;
 129         int minproto, maxproto;
 130
 131         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 132         if ( !sbi )
 133                 goto fail_unlock;
 134         memset(sbi, 0, sizeof(*sbi));
 135         DPRINTK(("autofs: starting up, sbi = %p\n",sbi));
 136
 137         s->s_fs_info = sbi;
 138         sbi->magic = AUTOFS_SBI_MAGIC;
 139         sbi->catatonic = 0;
 140         sbi->exp_timeout = 0;
 141         sbi->oz_pgrp = process_group(current);
 142         autofs_initialize_hash(&sbi->dirhash);
 143         sbi->queues = NULL;
 144         memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
 145         sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
 146         s->s_blocksize = 1024;
 147         s->s_blocksize_bits = 10;
 148         s->s_magic = AUTOFS_SUPER_MAGIC;
 149         s->s_op = &autofs_sops;
 150         s->s_time_gran = 1;
 151         sbi->sb = s;
 152
 153         root_inode = iget(s, AUTOFS_ROOT_INO);
 154         root = d_alloc_root(root_inode);
 155         pipe = NULL;
 156
 157         if (!root)
 158                 goto fail_iput;
 159
 160         /* Can this call block?  - WTF cares? s is locked. */
 161         if ( parse_options(data,&pipefd,&root_inode->i_uid,&root_inode->i_gid,&sbi->oz_pgrp,&minproto,&maxproto) ) {
 162                 printk("autofs: called with bogus options\n");
 163                 goto fail_dput;
 164         }
 165
 166         /* Couldn't this be tested earlier? */
 167         if ( minproto > AUTOFS_PROTO_VERSION ||
 168              maxproto < AUTOFS_PROTO_VERSION ) {
 169                 printk("autofs: kernel does not match daemon version\n");
 170                 goto fail_dput;
 171         }
 172
 173         DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, sbi->oz_pgrp));
 174         pipe = fget(pipefd);
 175
 176         if ( !pipe ) {
 177                 printk("autofs: could not open pipe file descriptor\n");
 178                 goto fail_dput;
 179         }
 180         if ( !pipe->f_op || !pipe->f_op->write )
 181                 goto fail_fput;
 182         sbi->pipe = pipe;
 183
 184         /*
 185          * Success! Install the root dentry now to indicate completion.
 186          */
 187         s->s_root = root;
 188         return 0;
 189
 190 fail_fput:
 191         printk("autofs: pipe file descriptor does not contain proper ops\n");
 192         fput(pipe);
 193 fail_dput:
 194         dput(root);
 195         goto fail_free;
 196 fail_iput:
 197         printk("autofs: get root dentry failed\n");
 198         iput(root_inode);
 199 fail_free:
 200         kfree(sbi);
 201 fail_unlock:
 202         return -EINVAL;
 203 }
 204
 205 static void autofs_read_inode(struct inode *inode)
 206 {
 207         ino_t ino = inode->i_ino;
 208         unsigned int n;
 209         struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
 210
 211         /* Initialize to the default case (stub directory) */
 212
 213         inode->i_op = &simple_dir_inode_operations;
 214         inode->i_fop = &simple_dir_operations;
 215         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 216         inode->i_nlink = 2;
 217         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 218         inode->i_blocks = 0;
 219         inode->i_blksize = 1024;
 220
 221         if ( ino == AUTOFS_ROOT_INO ) {
 222                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
 223                 inode->i_op = &autofs_root_inode_operations;
 224                 inode->i_fop = &autofs_root_operations;
 225                 inode->i_uid = inode->i_gid = 0; /* Changed in read_super */
 226                 return;
 227         }
 228
 229         inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
 230         inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
 231
 232         if ( ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO ) {
 233                 /* Symlink inode - should be in symlink list */
 234                 struct autofs_symlink *sl;
 235
 236                 n = ino - AUTOFS_FIRST_SYMLINK;
 237                 if ( n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
 238                         printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
 239                         return;
 240                 }
 241
 242                 inode->i_op = &autofs_symlink_inode_operations;
 243                 sl = &sbi->symlink[n];
 244                 inode->u.generic_ip = sl;
 245                 inode->i_mode = S_IFLNK | S_IRWXUGO;
 246                 inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
 247                 inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
 248                 inode->i_size = sl->len;
 249                 inode->i_nlink = 1;
 250         }
 251 }