linux/fs/proc/root.c
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   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/mount.h>
  20#include <linux/pid_namespace.h>
  21
  22#include "internal.h"
  23
  24static int proc_test_super(struct super_block *sb, void *data)
  25{
  26        return sb->s_fs_info == data;
  27}
  28
  29static int proc_set_super(struct super_block *sb, void *data)
  30{
  31        struct pid_namespace *ns;
  32
  33        ns = (struct pid_namespace *)data;
  34        sb->s_fs_info = get_pid_ns(ns);
  35        return set_anon_super(sb, NULL);
  36}
  37
  38static struct dentry *proc_mount(struct file_system_type *fs_type,
  39        int flags, const char *dev_name, void *data)
  40{
  41        int err;
  42        struct super_block *sb;
  43        struct pid_namespace *ns;
  44        struct proc_inode *ei;
  45
  46        if (flags & MS_KERNMOUNT)
  47                ns = (struct pid_namespace *)data;
  48        else
  49                ns = current->nsproxy->pid_ns;
  50
  51        sb = sget(fs_type, proc_test_super, proc_set_super, ns);
  52        if (IS_ERR(sb))
  53                return ERR_CAST(sb);
  54
  55        if (!sb->s_root) {
  56                sb->s_flags = flags;
  57                err = proc_fill_super(sb);
  58                if (err) {
  59                        deactivate_locked_super(sb);
  60                        return ERR_PTR(err);
  61                }
  62
  63                sb->s_flags |= MS_ACTIVE;
  64        }
  65
  66        ei = PROC_I(sb->s_root->d_inode);
  67        if (!ei->pid) {
  68                rcu_read_lock();
  69                ei->pid = get_pid(find_pid_ns(1, ns));
  70                rcu_read_unlock();
  71        }
  72
  73        return dget(sb->s_root);
  74}
  75
  76static void proc_kill_sb(struct super_block *sb)
  77{
  78        struct pid_namespace *ns;
  79
  80        ns = (struct pid_namespace *)sb->s_fs_info;
  81        kill_anon_super(sb);
  82        put_pid_ns(ns);
  83}
  84
  85static struct file_system_type proc_fs_type = {
  86        .name           = "proc",
  87        .mount          = proc_mount,
  88        .kill_sb        = proc_kill_sb,
  89};
  90
  91void __init proc_root_init(void)
  92{
  93        struct vfsmount *mnt;
  94        int err;
  95
  96        proc_init_inodecache();
  97        err = register_filesystem(&proc_fs_type);
  98        if (err)
  99                return;
 100        mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
 101        if (IS_ERR(mnt)) {
 102                unregister_filesystem(&proc_fs_type);
 103                return;
 104        }
 105
 106        init_pid_ns.proc_mnt = mnt;
 107        proc_symlink("mounts", NULL, "self/mounts");
 108
 109        proc_net_init();
 110
 111#ifdef CONFIG_SYSVIPC
 112        proc_mkdir("sysvipc", NULL);
 113#endif
 114        proc_mkdir("fs", NULL);
 115        proc_mkdir("driver", NULL);
 116        proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
 117#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
 118        /* just give it a mountpoint */
 119        proc_mkdir("openprom", NULL);
 120#endif
 121        proc_tty_init();
 122#ifdef CONFIG_PROC_DEVICETREE
 123        proc_device_tree_init();
 124#endif
 125        proc_mkdir("bus", NULL);
 126        proc_sys_init();
 127}
 128
 129static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
 130)
 131{
 132        generic_fillattr(dentry->d_inode, stat);
 133        stat->nlink = proc_root.nlink + nr_processes();
 134        return 0;
 135}
 136
 137static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
 138{
 139        if (!proc_lookup(dir, dentry, nd)) {
 140                return NULL;
 141        }
 142        
 143        return proc_pid_lookup(dir, dentry, nd);
 144}
 145
 146static int proc_root_readdir(struct file * filp,
 147        void * dirent, filldir_t filldir)
 148{
 149        unsigned int nr = filp->f_pos;
 150        int ret;
 151
 152        if (nr < FIRST_PROCESS_ENTRY) {
 153                int error = proc_readdir(filp, dirent, filldir);
 154                if (error <= 0)
 155                        return error;
 156                filp->f_pos = FIRST_PROCESS_ENTRY;
 157        }
 158
 159        ret = proc_pid_readdir(filp, dirent, filldir);
 160        return ret;
 161}
 162
 163/*
 164 * The root /proc directory is special, as it has the
 165 * <pid> directories. Thus we don't use the generic
 166 * directory handling functions for that..
 167 */
 168static const struct file_operations proc_root_operations = {
 169        .read            = generic_read_dir,
 170        .readdir         = proc_root_readdir,
 171        .llseek         = default_llseek,
 172};
 173
 174/*
 175 * proc root can do almost nothing..
 176 */
 177static const struct inode_operations proc_root_inode_operations = {
 178        .lookup         = proc_root_lookup,
 179        .getattr        = proc_root_getattr,
 180};
 181
 182/*
 183 * This is the root "inode" in the /proc tree..
 184 */
 185struct proc_dir_entry proc_root = {
 186        .low_ino        = PROC_ROOT_INO, 
 187        .namelen        = 5, 
 188        .name           = "/proc",
 189        .mode           = S_IFDIR | S_IRUGO | S_IXUGO, 
 190        .nlink          = 2, 
 191        .count          = ATOMIC_INIT(1),
 192        .proc_iops      = &proc_root_inode_operations, 
 193        .proc_fops      = &proc_root_operations,
 194        .parent         = &proc_root,
 195};
 196
 197int pid_ns_prepare_proc(struct pid_namespace *ns)
 198{
 199        struct vfsmount *mnt;
 200
 201        mnt = kern_mount_data(&proc_fs_type, ns);
 202        if (IS_ERR(mnt))
 203                return PTR_ERR(mnt);
 204
 205        ns->proc_mnt = mnt;
 206        return 0;
 207}
 208
 209void pid_ns_release_proc(struct pid_namespace *ns)
 210{
 211        mntput(ns->proc_mnt);
 212}
 213