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