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 int proc_get_sb(struct file_system_type *fs_type, 39 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 40{ 41 int err; 42 struct super_block *sb; 43 struct pid_namespace *ns; 44 struct proc_inode *ei; 45 46 if (proc_mnt) { 47 /* Seed the root directory with a pid so it doesn't need 48 * to be special in base.c. I would do this earlier but 49 * the only task alive when /proc is mounted the first time 50 * is the init_task and it doesn't have any pids. 51 */ 52 ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode); 53 if (!ei->pid) 54 ei->pid = find_get_pid(1); 55 } 56 57 if (flags & MS_KERNMOUNT) 58 ns = (struct pid_namespace *)data; 59 else 60 ns = current->nsproxy->pid_ns; 61 62 sb = sget(fs_type, proc_test_super, proc_set_super, ns); 63 if (IS_ERR(sb)) 64 return PTR_ERR(sb); 65 66 if (!sb->s_root) { 67 sb->s_flags = flags; 68 err = proc_fill_super(sb); 69 if (err) { 70 deactivate_locked_super(sb); 71 return err; 72 } 73 74 ei = PROC_I(sb->s_root->d_inode); 75 if (!ei->pid) { 76 rcu_read_lock(); 77 ei->pid = get_pid(find_pid_ns(1, ns)); 78 rcu_read_unlock(); 79 } 80 81 sb->s_flags |= MS_ACTIVE; 82 ns->proc_mnt = mnt; 83 } 84 85 simple_set_mnt(mnt, sb); 86 return 0; 87} 88 89static void proc_kill_sb(struct super_block *sb) 90{ 91 struct pid_namespace *ns; 92 93 ns = (struct pid_namespace *)sb->s_fs_info; 94 kill_anon_super(sb); 95 put_pid_ns(ns); 96} 97 98static struct file_system_type proc_fs_type = { 99 .name = "proc", 100 .get_sb = proc_get_sb, 101 .kill_sb = proc_kill_sb, 102}; 103 104void __init proc_root_init(void) 105{ 106 int err; 107 108 proc_init_inodecache(); 109 err = register_filesystem(&proc_fs_type); 110 if (err) 111 return; 112 proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns); 113 if (IS_ERR(proc_mnt)) { 114 unregister_filesystem(&proc_fs_type); 115 return; 116 } 117 118 proc_symlink("mounts", NULL, "self/mounts"); 119 120 proc_net_init(); 121 122#ifdef CONFIG_SYSVIPC 123 proc_mkdir("sysvipc", NULL); 124#endif 125 proc_mkdir("fs", NULL); 126 proc_mkdir("driver", NULL); 127 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */ 128#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) 129 /* just give it a mountpoint */ 130 proc_mkdir("openprom", NULL); 131#endif 132 proc_tty_init(); 133#ifdef CONFIG_PROC_DEVICETREE 134 proc_device_tree_init(); 135#endif 136 proc_mkdir("bus", NULL); 137 proc_sys_init(); 138} 139 140static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat 141) 142{ 143 generic_fillattr(dentry->d_inode, stat); 144 stat->nlink = proc_root.nlink + nr_processes(); 145 return 0; 146} 147 148static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 149{ 150 if (!proc_lookup(dir, dentry, nd)) { 151 return NULL; 152 } 153 154 return proc_pid_lookup(dir, dentry, nd); 155} 156 157static int proc_root_readdir(struct file * filp, 158 void * dirent, filldir_t filldir) 159{ 160 unsigned int nr = filp->f_pos; 161 int ret; 162 163 if (nr < FIRST_PROCESS_ENTRY) { 164 int error = proc_readdir(filp, dirent, filldir); 165 if (error <= 0) 166 return error; 167 filp->f_pos = FIRST_PROCESS_ENTRY; 168 } 169 170 ret = proc_pid_readdir(filp, dirent, filldir); 171 return ret; 172} 173 174/* 175 * The root /proc directory is special, as it has the 176 * <pid> directories. Thus we don't use the generic 177 * directory handling functions for that.. 178 */ 179static const struct file_operations proc_root_operations = { 180 .read = generic_read_dir, 181 .readdir = proc_root_readdir, 182}; 183 184/* 185 * proc root can do almost nothing.. 186 */ 187static const struct inode_operations proc_root_inode_operations = { 188 .lookup = proc_root_lookup, 189 .getattr = proc_root_getattr, 190}; 191 192/* 193 * This is the root "inode" in the /proc tree.. 194 */ 195struct proc_dir_entry proc_root = { 196 .low_ino = PROC_ROOT_INO, 197 .namelen = 5, 198 .name = "/proc", 199 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 200 .nlink = 2, 201 .count = ATOMIC_INIT(1), 202 .proc_iops = &proc_root_inode_operations, 203 .proc_fops = &proc_root_operations, 204 .parent = &proc_root, 205}; 206 207int pid_ns_prepare_proc(struct pid_namespace *ns) 208{ 209 struct vfsmount *mnt; 210 211 mnt = kern_mount_data(&proc_fs_type, ns); 212 if (IS_ERR(mnt)) 213 return PTR_ERR(mnt); 214 215 return 0; 216} 217 218void pid_ns_release_proc(struct pid_namespace *ns) 219{ 220 mntput(ns->proc_mnt); 221} 222