drivers/isdn/capi/capifs.c

   1 /* $Id: capifs.c,v 1.1.2.3 2004/01/16 21:09:26 keil Exp $
   2  *
   3  * Copyright 2000 by Carsten Paeth <calle@calle.de>
   4  *
   5  * Heavily based on devpts filesystem from H. Peter Anvin
   6  *
   7  * This software may be used and distributed according to the terms
   8  * of the GNU General Public License, incorporated herein by reference.
   9  *
  10  */
  11
  12 #include <linux/fs.h>
  13 #include <linux/mount.h>
  14 #include <linux/namei.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/ctype.h>
  18
  19 MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem");
  20 MODULE_AUTHOR("Carsten Paeth");
  21 MODULE_LICENSE("GPL");
  22
  23 /* ------------------------------------------------------------------ */
  24
  25 static char *revision = "$Revision: 1.1.2.3 $";
  26
  27 /* ------------------------------------------------------------------ */
  28
  29 #define CAPIFS_SUPER_MAGIC (('C'<<8)|'N')
  30
  31 static struct vfsmount *capifs_mnt;
  32 static struct dentry *capifs_root;
  33
  34 static struct {
  35         int setuid;
  36         int setgid;
  37         uid_t   uid;
  38         gid_t   gid;
  39         umode_t mode;
  40 } config = {.mode = 0600};
  41
  42 /* ------------------------------------------------------------------ */
  43
  44 static int capifs_remount(struct super_block *s, int *flags, char *data)
  45 {
  46         int setuid = 0;
  47         int setgid = 0;
  48         uid_t uid = 0;
  49         gid_t gid = 0;
  50         umode_t mode = 0600;
  51         char *this_char;
  52
  53         this_char = NULL;
  54         while ((this_char = strsep(&data, ",")) != NULL) {
  55                 int n;
  56                 char dummy;
  57                 if (!*this_char)
  58                         continue;
  59                 if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
  60                         setuid = 1;
  61                         uid = n;
  62                 } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
  63                         setgid = 1;
  64                         gid = n;
  65                 } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
  66                         mode = n & ~S_IFMT;
  67                 else {
  68                         printk("capifs: called with bogus options\n");
  69                         return -EINVAL;
  70                 }
  71         }
  72         config.setuid  = setuid;
  73         config.setgid  = setgid;
  74         config.uid     = uid;
  75         config.gid     = gid;
  76         config.mode    = mode;
  77         return 0;
  78 }
  79
  80 static struct super_operations capifs_sops =
  81 {
  82         .statfs         = simple_statfs,
  83         .remount_fs     = capifs_remount,
  84 };
  85
  86
  87 static int
  88 capifs_fill_super(struct super_block *s, void *data, int silent)
  89 {
  90         struct inode * inode;
  91
  92         s->s_blocksize = 1024;
  93         s->s_blocksize_bits = 10;
  94         s->s_magic = CAPIFS_SUPER_MAGIC;
  95         s->s_op = &capifs_sops;
  96         s->s_time_gran = 1;
  97
  98         inode = new_inode(s);
  99         if (!inode)
 100                 goto fail;
 101         inode->i_ino = 1;
 102         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 103         inode->i_blocks = 0;
 104         inode->i_blksize = 1024;
 105         inode->i_uid = inode->i_gid = 0;
 106         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
 107         inode->i_op = &simple_dir_inode_operations;
 108         inode->i_fop = &simple_dir_operations;
 109         inode->i_nlink = 2;
 110
 111         capifs_root = s->s_root = d_alloc_root(inode);
 112         if (s->s_root)
 113                 return 0;
 114
 115         printk("capifs: get root dentry failed\n");
 116         iput(inode);
 117 fail:
 118         return -ENOMEM;
 119 }
 120
 121 static struct super_block *capifs_get_sb(struct file_system_type *fs_type,
 122         int flags, const char *dev_name, void *data)
 123 {
 124         return get_sb_single(fs_type, flags, data, capifs_fill_super);
 125 }
 126
 127 static struct file_system_type capifs_fs_type = {
 128         .owner          = THIS_MODULE,
 129         .name           = "capifs",
 130         .get_sb         = capifs_get_sb,
 131         .kill_sb        = kill_anon_super,
 132 };
 133
 134 static struct dentry *get_node(int num)
 135 {
 136         char s[10];
 137         struct dentry *root = capifs_root;
 138         down(&root->d_inode->i_sem);
 139         return lookup_one_len(s, root, sprintf(s, "%d", num));
 140 }
 141
 142 void capifs_new_ncci(unsigned int number, dev_t device)
 143 {
 144         struct dentry *dentry;
 145         struct inode *inode = new_inode(capifs_mnt->mnt_sb);
 146         if (!inode)
 147                 return;
 148         inode->i_ino = number+2;
 149         inode->i_blksize = 1024;
 150         inode->i_uid = config.setuid ? config.uid : current->fsuid;
 151         inode->i_gid = config.setgid ? config.gid : current->fsgid;
 152         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 153         init_special_inode(inode, S_IFCHR|config.mode, device);
 154         //inode->i_op = &capifs_file_inode_operations;
 155
 156         dentry = get_node(number);
 157         if (!IS_ERR(dentry) && !dentry->d_inode)
 158                 d_instantiate(dentry, inode);
 159         up(&capifs_root->d_inode->i_sem);
 160 }
 161
 162 void capifs_free_ncci(unsigned int number)
 163 {
 164         struct dentry *dentry = get_node(number);
 165
 166         if (!IS_ERR(dentry)) {
 167                 struct inode *inode = dentry->d_inode;
 168                 if (inode) {
 169                         inode->i_nlink--;
 170                         d_delete(dentry);
 171                         dput(dentry);
 172                 }
 173                 dput(dentry);
 174         }
 175         up(&capifs_root->d_inode->i_sem);
 176 }
 177
 178 static int __init capifs_init(void)
 179 {
 180         char rev[32];
 181         char *p;
 182         int err;
 183
 184         if ((p = strchr(revision, ':')) != 0 && p[1]) {
 185                 strlcpy(rev, p + 2, sizeof(rev));
 186                 if ((p = strchr(rev, '$')) != 0 && p > rev)
 187                    *(p-1) = 0;
 188         } else
 189                 strcpy(rev, "1.0");
 190
 191         err = register_filesystem(&capifs_fs_type);
 192         if (!err) {
 193                 capifs_mnt = kern_mount(&capifs_fs_type);
 194                 if (IS_ERR(capifs_mnt))
 195                         err = PTR_ERR(capifs_mnt);
 196         }
 197         if (!err)
 198                 printk(KERN_NOTICE "capifs: Rev %s\n", rev);
 199         return err;
 200 }
 201
 202 static void __exit capifs_exit(void)
 203 {
 204         unregister_filesystem(&capifs_fs_type);
 205         mntput(capifs_mnt);
 206 }
 207
 208 EXPORT_SYMBOL(capifs_new_ncci);
 209 EXPORT_SYMBOL(capifs_free_ncci);
 210
 211 module_init(capifs_init);
 212 module_exit(capifs_exit);