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