aboutsummaryrefslogtreecommitdiff
path: root/fs/devpts/inode.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/devpts/inode.c')
-rw-r--r--fs/devpts/inode.c242
1 files changed, 242 insertions, 0 deletions
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
new file mode 100644
index 00000000000..1571c8d6c23
--- /dev/null
+++ b/fs/devpts/inode.c
@@ -0,0 +1,242 @@
+/* -*- linux-c -*- --------------------------------------------------------- *
+ *
+ * linux/fs/devpts/inode.c
+ *
+ * Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * ------------------------------------------------------------------------- */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/tty.h>
+#include <linux/devpts_fs.h>
+#include <linux/xattr.h>
+
+#define DEVPTS_SUPER_MAGIC 0x1cd1
+
+extern struct xattr_handler devpts_xattr_security_handler;
+
+static struct xattr_handler *devpts_xattr_handlers[] = {
+#ifdef CONFIG_DEVPTS_FS_SECURITY
+ &devpts_xattr_security_handler,
+#endif
+ NULL
+};
+
+static struct inode_operations devpts_file_inode_operations = {
+#ifdef CONFIG_DEVPTS_FS_XATTR
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = generic_listxattr,
+ .removexattr = generic_removexattr,
+#endif
+};
+
+static struct vfsmount *devpts_mnt;
+static struct dentry *devpts_root;
+
+static struct {
+ int setuid;
+ int setgid;
+ uid_t uid;
+ gid_t gid;
+ umode_t mode;
+} config = {.mode = 0600};
+
+static int devpts_remount(struct super_block *sb, 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;
+
+ 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 {
+ printk("devpts: called with bogus options\n");
+ return -EINVAL;
+ }
+ }
+ config.setuid = setuid;
+ config.setgid = setgid;
+ config.uid = uid;
+ config.gid = gid;
+ config.mode = mode;
+
+ return 0;
+}
+
+static struct super_operations devpts_sops = {
+ .statfs = simple_statfs,
+ .remount_fs = devpts_remount,
+};
+
+static int
+devpts_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 = DEVPTS_SUPER_MAGIC;
+ s->s_op = &devpts_sops;
+ s->s_xattr = devpts_xattr_handlers;
+ 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_blocks = 0;
+ inode->i_blksize = 1024;
+ inode->i_uid = inode->i_gid = 0;
+ 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;
+
+ devpts_root = s->s_root = d_alloc_root(inode);
+ if (s->s_root)
+ return 0;
+
+ printk("devpts: get root dentry failed\n");
+ iput(inode);
+fail:
+ return -ENOMEM;
+}
+
+static struct super_block *devpts_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return get_sb_single(fs_type, flags, data, devpts_fill_super);
+}
+
+static struct file_system_type devpts_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "devpts",
+ .get_sb = devpts_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
+/*
+ * The normal naming convention is simply /dev/pts/<number>; this conforms
+ * to the System V naming convention
+ */
+
+static struct dentry *get_node(int num)
+{
+ char s[12];
+ struct dentry *root = devpts_root;
+ down(&root->d_inode->i_sem);
+ return lookup_one_len(s, root, sprintf(s, "%d", num));
+}
+
+int devpts_pty_new(struct tty_struct *tty)
+{
+ int number = tty->index;
+ struct tty_driver *driver = tty->driver;
+ dev_t device = MKDEV(driver->major, driver->minor_start+number);
+ struct dentry *dentry;
+ struct inode *inode = new_inode(devpts_mnt->mnt_sb);
+
+ /* We're supposed to be given the slave end of a pty */
+ BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);
+ BUG_ON(driver->subtype != PTY_TYPE_SLAVE);
+
+ if (!inode)
+ return -ENOMEM;
+
+ inode->i_ino = number+2;
+ inode->i_blksize = 1024;
+ 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;
+ init_special_inode(inode, S_IFCHR|config.mode, device);
+ inode->i_op = &devpts_file_inode_operations;
+ inode->u.generic_ip = tty;
+
+ dentry = get_node(number);
+ if (!IS_ERR(dentry) && !dentry->d_inode)
+ d_instantiate(dentry, inode);
+
+ up(&devpts_root->d_inode->i_sem);
+
+ return 0;
+}
+
+struct tty_struct *devpts_get_tty(int number)
+{
+ struct dentry *dentry = get_node(number);
+ struct tty_struct *tty;
+
+ tty = NULL;
+ if (!IS_ERR(dentry)) {
+ if (dentry->d_inode)
+ tty = dentry->d_inode->u.generic_ip;
+ dput(dentry);
+ }
+
+ up(&devpts_root->d_inode->i_sem);
+
+ return tty;
+}
+
+void devpts_pty_kill(int number)
+{
+ struct dentry *dentry = get_node(number);
+
+ if (!IS_ERR(dentry)) {
+ struct inode *inode = dentry->d_inode;
+ if (inode) {
+ inode->i_nlink--;
+ d_delete(dentry);
+ dput(dentry);
+ }
+ dput(dentry);
+ }
+ up(&devpts_root->d_inode->i_sem);
+}
+
+static int __init init_devpts_fs(void)
+{
+ int err = register_filesystem(&devpts_fs_type);
+ if (!err) {
+ devpts_mnt = kern_mount(&devpts_fs_type);
+ if (IS_ERR(devpts_mnt))
+ err = PTR_ERR(devpts_mnt);
+ }
+ return err;
+}
+
+static void __exit exit_devpts_fs(void)
+{
+ unregister_filesystem(&devpts_fs_type);
+ mntput(devpts_mnt);
+}
+
+module_init(init_devpts_fs)
+module_exit(exit_devpts_fs)
+MODULE_LICENSE("GPL");