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 #include <linux/parser.h> 22 23 #include "internal.h" 24 25 static int proc_test_super(struct super_block *sb, void *data) 26 { 27 return sb->s_fs_info == data; 28 } 29 30 static int proc_set_super(struct super_block *sb, void *data) 31 { 32 int err = set_anon_super(sb, NULL); 33 if (!err) { 34 struct pid_namespace *ns = (struct pid_namespace *)data; 35 sb->s_fs_info = get_pid_ns(ns); 36 } 37 return err; 38 } 39 40 enum { 41 Opt_gid, Opt_hidepid, Opt_err, 42 }; 43 44 static const match_table_t tokens = { 45 {Opt_hidepid, "hidepid=%u"}, 46 {Opt_gid, "gid=%u"}, 47 {Opt_err, NULL}, 48 }; 49 50 static int proc_parse_options(char *options, struct pid_namespace *pid) 51 { 52 char *p; 53 substring_t args[MAX_OPT_ARGS]; 54 int option; 55 56 if (!options) 57 return 1; 58 59 while ((p = strsep(&options, ",")) != NULL) { 60 int token; 61 if (!*p) 62 continue; 63 64 args[0].to = args[0].from = 0; 65 token = match_token(p, tokens, args); 66 switch (token) { 67 case Opt_gid: 68 if (match_int(&args[0], &option)) 69 return 0; 70 pid->pid_gid = option; 71 break; 72 case Opt_hidepid: 73 if (match_int(&args[0], &option)) 74 return 0; 75 if (option < 0 || option > 2) { 76 pr_err("proc: hidepid value must be between 0 and 2.\n"); 77 return 0; 78 } 79 pid->hide_pid = option; 80 break; 81 default: 82 pr_err("proc: unrecognized mount option \"%s\" " 83 "or missing value\n", p); 84 return 0; 85 } 86 } 87 88 return 1; 89 } 90 91 int proc_remount(struct super_block *sb, int *flags, char *data) 92 { 93 struct pid_namespace *pid = sb->s_fs_info; 94 return !proc_parse_options(data, pid); 95 } 96 97 static struct dentry *proc_mount(struct file_system_type *fs_type, 98 int flags, const char *dev_name, void *data) 99 { 100 int err; 101 struct super_block *sb; 102 struct pid_namespace *ns; 103 struct proc_inode *ei; 104 char *options; 105 106 if (flags & MS_KERNMOUNT) { 107 ns = (struct pid_namespace *)data; 108 options = NULL; 109 } else { 110 ns = current->nsproxy->pid_ns; 111 options = data; 112 } 113 114 sb = sget(fs_type, proc_test_super, proc_set_super, ns); 115 if (IS_ERR(sb)) 116 return ERR_CAST(sb); 117 118 if (!sb->s_root) { 119 sb->s_flags = flags; 120 if (!proc_parse_options(options, ns)) { 121 deactivate_locked_super(sb); 122 return ERR_PTR(-EINVAL); 123 } 124 err = proc_fill_super(sb); 125 if (err) { 126 deactivate_locked_super(sb); 127 return ERR_PTR(err); 128 } 129 130 sb->s_flags |= MS_ACTIVE; 131 } 132 133 ei = PROC_I(sb->s_root->d_inode); 134 if (!ei->pid) { 135 rcu_read_lock(); 136 ei->pid = get_pid(find_pid_ns(1, ns)); 137 rcu_read_unlock(); 138 } 139 140 return dget(sb->s_root); 141 } 142 143 static void proc_kill_sb(struct super_block *sb) 144 { 145 struct pid_namespace *ns; 146 147 ns = (struct pid_namespace *)sb->s_fs_info; 148 kill_anon_super(sb); 149 put_pid_ns(ns); 150 } 151 152 static struct file_system_type proc_fs_type = { 153 .name = "proc", 154 .mount = proc_mount, 155 .kill_sb = proc_kill_sb, 156 }; 157 158 void __init proc_root_init(void) 159 { 160 int err; 161 162 proc_init_inodecache(); 163 err = register_filesystem(&proc_fs_type); 164 if (err) 165 return; 166 err = pid_ns_prepare_proc(&init_pid_ns); 167 if (err) { 168 unregister_filesystem(&proc_fs_type); 169 return; 170 } 171 172 proc_symlink("mounts", NULL, "self/mounts"); 173 174 proc_net_init(); 175 176 #ifdef CONFIG_SYSVIPC 177 proc_mkdir("sysvipc", NULL); 178 #endif 179 proc_mkdir("fs", NULL); 180 proc_mkdir("driver", NULL); 181 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */ 182 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) 183 /* just give it a mountpoint */ 184 proc_mkdir("openprom", NULL); 185 #endif 186 proc_tty_init(); 187 #ifdef CONFIG_PROC_DEVICETREE 188 proc_device_tree_init(); 189 #endif 190 proc_mkdir("bus", NULL); 191 proc_sys_init(); 192 } 193 194 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat 195 ) 196 { 197 generic_fillattr(dentry->d_inode, stat); 198 stat->nlink = proc_root.nlink + nr_processes(); 199 return 0; 200 } 201 202 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 203 { 204 if (!proc_lookup(dir, dentry, nd)) { 205 return NULL; 206 } 207 208 return proc_pid_lookup(dir, dentry, nd); 209 } 210 211 static int proc_root_readdir(struct file * filp, 212 void * dirent, filldir_t filldir) 213 { 214 unsigned int nr = filp->f_pos; 215 int ret; 216 217 if (nr < FIRST_PROCESS_ENTRY) { 218 int error = proc_readdir(filp, dirent, filldir); 219 if (error <= 0) 220 return error; 221 filp->f_pos = FIRST_PROCESS_ENTRY; 222 } 223 224 ret = proc_pid_readdir(filp, dirent, filldir); 225 return ret; 226 } 227 228 /* 229 * The root /proc directory is special, as it has the 230 * <pid> directories. Thus we don't use the generic 231 * directory handling functions for that.. 232 */ 233 static const struct file_operations proc_root_operations = { 234 .read = generic_read_dir, 235 .readdir = proc_root_readdir, 236 .llseek = default_llseek, 237 }; 238 239 /* 240 * proc root can do almost nothing.. 241 */ 242 static const struct inode_operations proc_root_inode_operations = { 243 .lookup = proc_root_lookup, 244 .getattr = proc_root_getattr, 245 }; 246 247 /* 248 * This is the root "inode" in the /proc tree.. 249 */ 250 struct proc_dir_entry proc_root = { 251 .low_ino = PROC_ROOT_INO, 252 .namelen = 5, 253 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 254 .nlink = 2, 255 .count = ATOMIC_INIT(1), 256 .proc_iops = &proc_root_inode_operations, 257 .proc_fops = &proc_root_operations, 258 .parent = &proc_root, 259 .name = "/proc", 260 }; 261 262 int pid_ns_prepare_proc(struct pid_namespace *ns) 263 { 264 struct vfsmount *mnt; 265 266 mnt = kern_mount_data(&proc_fs_type, ns); 267 if (IS_ERR(mnt)) 268 return PTR_ERR(mnt); 269 270 ns->proc_mnt = mnt; 271 return 0; 272 } 273 274 void pid_ns_release_proc(struct pid_namespace *ns) 275 { 276 kern_unmount(ns->proc_mnt); 277 } 278