/*
       *  linux/fs/proc/root.c
       *
       *  Copyright (C) 1991, 1992 Linus Torvalds
       *
       *  proc root directory handling functions
       */
      
      #include <asm/uaccess.h>
      
      #include <linux/errno.h>
      #include <linux/sched.h>
      #include <linux/proc_fs.h>
      #include <linux/stat.h>
      #include <linux/config.h>
      #include <linux/init.h>
      #include <asm/bitops.h>
      
      struct proc_dir_entry *proc_net, *proc_bus, *proc_root_fs, *proc_root_driver;
      
      #ifdef CONFIG_SYSCTL
      struct proc_dir_entry *proc_sys_root;
      #endif
      
  25  void __init proc_root_init(void)
      {
      	proc_misc_init();
      	proc_net = proc_mkdir("net", 0);
      #ifdef CONFIG_SYSVIPC
      	proc_mkdir("sysvipc", 0);
      #endif
      #ifdef CONFIG_SYSCTL
      	proc_sys_root = proc_mkdir("sys", 0);
      #endif
      	proc_root_fs = proc_mkdir("fs", 0);
      	proc_root_driver = proc_mkdir("driver", 0);
      #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
      	/* just give it a mountpoint */
      	proc_mkdir("openprom", 0);
      #endif
      	proc_tty_init();
      #ifdef CONFIG_PROC_DEVICETREE
      	proc_device_tree_init();
      #endif
      	proc_bus = proc_mkdir("bus", 0);
      }
      
  48  static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry)
      {
  50  	if (dir->i_ino == PROC_ROOT_INO) { /* check for safety... */
      		int nlink = proc_root.nlink;
      
      		nlink += nr_threads;
      
      		dir->i_nlink = nlink;
      	}
      
  58  	if (!proc_lookup(dir, dentry))
  59  		return NULL;
      	
  61  	return proc_pid_lookup(dir, dentry);
      }
      
  64  static int proc_root_readdir(struct file * filp,
      	void * dirent, filldir_t filldir)
      {
      	unsigned int nr = filp->f_pos;
      
  69  	if (nr < FIRST_PROCESS_ENTRY) {
      		int error = proc_readdir(filp, dirent, filldir);
  71  		if (error <= 0)
  72  			return error;
      		filp->f_pos = FIRST_PROCESS_ENTRY;
      	}
      
  76  	return proc_pid_readdir(filp, dirent, filldir);
      }
      
      /*
       * The root /proc directory is special, as it has the
       * <pid> directories. Thus we don't use the generic
       * directory handling functions for that..
       */
      static struct file_operations proc_root_operations = {
      	read:		 generic_read_dir,
      	readdir:	 proc_root_readdir,
      };
      
      /*
       * proc root can do almost nothing..
       */
      static struct inode_operations proc_root_inode_operations = {
      	lookup:		proc_root_lookup,
      };
      
      /*
       * This is the root "inode" in the /proc tree..
       */
      struct proc_dir_entry proc_root = {
      	low_ino:	PROC_ROOT_INO, 
      	namelen:	5, 
      	name:		"/proc",
      	mode:		S_IFDIR | S_IRUGO | S_IXUGO, 
      	nlink:		2, 
      	proc_iops:	&proc_root_inode_operations, 
      	proc_fops:	&proc_root_operations,
      	parent:		&proc_root,
      };