/* $Id: capifs.c,v 1.1.2.3 2004/01/16 21:09:26 keil Exp $ * * Copyright 2000 by Carsten Paeth * * Heavily based on devpts filesystem from H. Peter Anvin * * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * */ #include #include #include #include #include #include #include /* current */ #include "capifs.h" MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem"); MODULE_AUTHOR("Carsten Paeth"); MODULE_LICENSE("GPL"); /* ------------------------------------------------------------------ */ #define CAPIFS_SUPER_MAGIC (('C'<<8)|'N') static struct vfsmount *capifs_mnt; static int capifs_mnt_count; static struct { int setuid; int setgid; uid_t uid; gid_t gid; umode_t mode; } config = {.mode = 0600}; /* ------------------------------------------------------------------ */ static int capifs_remount(struct super_block *s, int *flags, char *data) { int setuid = 0; int setgid = 0; uid_t uid = 0; gid_t gid = 0; umode_t mode = 0600; char *this_char; char *new_opt = kstrdup(data, GFP_KERNEL); this_char = NULL; while ((this_char = strsep(&data, ",")) != NULL) { int n; char dummy; if (!*this_char) continue; if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) { setuid = 1; uid = n; } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) { setgid = 1; gid = n; } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1) mode = n & ~S_IFMT; else { kfree(new_opt); printk("capifs: called with bogus options\n"); return -EINVAL; } } mutex_lock(&s->s_root->d_inode->i_mutex); replace_mount_options(s, new_opt); config.setuid = setuid; config.setgid = setgid; config.uid = uid; config.gid = gid; config.mode = mode; mutex_unlock(&s->s_root->d_inode->i_mutex); return 0; } static const struct super_operations capifs_sops = { .statfs = simple_statfs, .remount_fs = capifs_remount, .show_options = generic_show_options, }; static int capifs_fill_super(struct super_block *s, void *data, int silent) { struct inode * inode; s->s_blocksize = 1024; s->s_blocksize_bits = 10; s->s_magic = CAPIFS_SUPER_MAGIC; s->s_op = &capifs_sops; s->s_time_gran = 1; inode = new_inode(s); if (!inode) goto fail; inode->i_ino = 1; inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; inode->i_nlink = 2; s->s_root = d_alloc_root(inode); if (s->s_root) return 0; printk("capifs: get root dentry failed\n"); iput(inode); fail: return -ENOMEM; } static int capifs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { return get_sb_single(fs_type, flags, data, capifs_fill_super, mnt); } static struct file_system_type capifs_fs_type = { .owner = THIS_MODULE, .name = "capifs", .get_sb = capifs_get_sb, .kill_sb = kill_anon_super, }; static struct dentry *new_ncci(unsigned int number, dev_t device) { struct super_block *s = capifs_mnt->mnt_sb; struct dentry *root = s->s_root; struct dentry *dentry; struct inode *inode; char name[10]; int namelen; mutex_lock(&root->d_inode->i_mutex); namelen = sprintf(name, "%d", number); dentry = lookup_one_len(name, root, namelen); if (IS_ERR(dentry)) { dentry = NULL; goto unlock_out; } if (dentry->d_inode) { dput(dentry); dentry = NULL; goto unlock_out; } inode = new_inode(s); if (!inode) { dput(dentry); dentry = NULL; goto unlock_out; } /* config contents is protected by root's i_mutex */ inode->i_uid = config.setuid ? config.uid : current_fsuid(); inode->i_gid = config.setgid ? config.gid : current_fsgid(); inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; inode->i_ino = number + 2; init_special_inode(inode, S_IFCHR|config.mode, device); d_instantiate(dentry, inode); dget(dentry); unlock_out: mutex_unlock(&root->d_inode->i_mutex); return dentry; } struct dentry *capifs_new_ncci(unsigned int number, dev_t device) { struct dentry *dentry; if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0) return NULL; dentry = new_ncci(number, device); if (!dentry) simple_release_fs(&capifs_mnt, &capifs_mnt_count); return dentry; } void capifs_free_ncci(struct dentry *dentry) { struct dentry *root = capifs_mnt->mnt_sb->s_root; struct inode *inode; if (!dentry) return; mutex_lock(&root->d_inode->i_mutex); inode = dentry->d_inode; if (inode) { drop_nlink(inode); d_delete(dentry); dput(dentry); } dput(dentry); mutex_unlock(&root->d_inode->i_mutex); simple_release_fs(&capifs_mnt, &capifs_mnt_count); } static int __init capifs_init(void) { return register_filesystem(&capifs_fs_type); } static void __exit capifs_exit(void) { unregister_filesystem(&capifs_fs_type); } EXPORT_SYMBOL(capifs_new_ncci); EXPORT_SYMBOL(capifs_free_ncci); module_init(capifs_init); module_exit(capifs_exit);