fs/proc/root.c

   1 /*
   2  *  linux/fs/proc/root.c
   3  *
   4  *  Copyright (C) 1991, 1992 Linus Torvalds
   5  *
   6  *  proc root directory handling functions
   7  */
   8
   9 #include <asm/uaccess.h>
  10
  11 #include <linux/errno.h>
  12 #include <linux/time.h>
  13 #include <linux/proc_fs.h>
  14 #include <linux/stat.h>
  15 #include <linux/init.h>
  16 #include <linux/sched.h>
  17 #include <linux/module.h>
  18 #include <linux/bitops.h>
  19 #include <linux/smp_lock.h>
  20 #include <linux/mount.h>
  21
  22 #include "internal.h"
  23
  24 struct proc_dir_entry *proc_bus, *proc_root_fs, *proc_root_driver;
  25
  26 static int proc_get_sb(struct file_system_type *fs_type,
  27         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
  28 {
  29         if (proc_mnt) {
  30                 /* Seed the root directory with a pid so it doesn't need
  31                  * to be special in base.c.  I would do this earlier but
  32                  * the only task alive when /proc is mounted the first time
  33                  * is the init_task and it doesn't have any pids.
  34                  */
  35                 struct proc_inode *ei;
  36                 ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode);
  37                 if (!ei->pid)
  38                         ei->pid = find_get_pid(1);
  39         }
  40         return get_sb_single(fs_type, flags, data, proc_fill_super, mnt);
  41 }
  42
  43 static struct file_system_type proc_fs_type = {
  44         .name           = "proc",
  45         .get_sb         = proc_get_sb,
  46         .kill_sb        = kill_anon_super,
  47 };
  48
  49 void __init proc_root_init(void)
  50 {
  51         int err = proc_init_inodecache();
  52         if (err)
  53                 return;
  54         err = register_filesystem(&proc_fs_type);
  55         if (err)
  56                 return;
  57         proc_mnt = kern_mount(&proc_fs_type);
  58         err = PTR_ERR(proc_mnt);
  59         if (IS_ERR(proc_mnt)) {
  60                 unregister_filesystem(&proc_fs_type);
  61                 return;
  62         }
  63         proc_misc_init();
  64
  65         proc_net_init();
  66
  67 #ifdef CONFIG_SYSVIPC
  68         proc_mkdir("sysvipc", NULL);
  69 #endif
  70         proc_root_fs = proc_mkdir("fs", NULL);
  71         proc_root_driver = proc_mkdir("driver", NULL);
  72         proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
  73 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
  74         /* just give it a mountpoint */
  75         proc_mkdir("openprom", NULL);
  76 #endif
  77         proc_tty_init();
  78 #ifdef CONFIG_PROC_DEVICETREE
  79         proc_device_tree_init();
  80 #endif
  81         proc_bus = proc_mkdir("bus", NULL);
  82         proc_sys_init();
  83 }
  84
  85 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
  86 )
  87 {
  88         generic_fillattr(dentry->d_inode, stat);
  89         stat->nlink = proc_root.nlink + nr_processes();
  90         return 0;
  91 }
  92
  93 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
  94 {
  95         if (!proc_lookup(dir, dentry, nd)) {
  96                 return NULL;
  97         }
  98
  99         return proc_pid_lookup(dir, dentry, nd);
 100 }
 101
 102 static int proc_root_readdir(struct file * filp,
 103         void * dirent, filldir_t filldir)
 104 {
 105         unsigned int nr = filp->f_pos;
 106         int ret;
 107
 108         lock_kernel();
 109
 110         if (nr < FIRST_PROCESS_ENTRY) {
 111                 int error = proc_readdir(filp, dirent, filldir);
 112                 if (error <= 0) {
 113                         unlock_kernel();
 114                         return error;
 115                 }
 116                 filp->f_pos = FIRST_PROCESS_ENTRY;
 117         }
 118         unlock_kernel();
 119
 120         ret = proc_pid_readdir(filp, dirent, filldir);
 121         return ret;
 122 }
 123
 124 /*
 125  * The root /proc directory is special, as it has the
 126  * <pid> directories. Thus we don't use the generic
 127  * directory handling functions for that..
 128  */
 129 static const struct file_operations proc_root_operations = {
 130         .read            = generic_read_dir,
 131         .readdir         = proc_root_readdir,
 132 };
 133
 134 /*
 135  * proc root can do almost nothing..
 136  */
 137 static const struct inode_operations proc_root_inode_operations = {
 138         .lookup         = proc_root_lookup,
 139         .getattr        = proc_root_getattr,
 140 };
 141
 142 /*
 143  * This is the root "inode" in the /proc tree..
 144  */
 145 struct proc_dir_entry proc_root = {
 146         .low_ino        = PROC_ROOT_INO,
 147         .namelen        = 5,
 148         .name           = "/proc",
 149         .mode           = S_IFDIR | S_IRUGO | S_IXUGO,
 150         .nlink          = 2,
 151         .proc_iops      = &proc_root_inode_operations,
 152         .proc_fops      = &proc_root_operations,
 153         .parent         = &proc_root,
 154 };
 155
 156 EXPORT_SYMBOL(proc_symlink);
 157 EXPORT_SYMBOL(proc_mkdir);
 158 EXPORT_SYMBOL(create_proc_entry);
 159 EXPORT_SYMBOL(remove_proc_entry);
 160 EXPORT_SYMBOL(proc_root);
 161 EXPORT_SYMBOL(proc_root_fs);
 162 EXPORT_SYMBOL(proc_bus);
 163 EXPORT_SYMBOL(proc_root_driver);