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 <linux/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/user_namespace.h> 20 #include <linux/mount.h> 21 #include <linux/pid_namespace.h> 22 #include <linux/parser.h> 23 #include <linux/cred.h> 24 25 #include "internal.h" 26 27 enum { 28 Opt_gid, Opt_hidepid, Opt_err, 29 }; 30 31 static const match_table_t tokens = { 32 {Opt_hidepid, "hidepid=%u"}, 33 {Opt_gid, "gid=%u"}, 34 {Opt_err, NULL}, 35 }; 36 37 int proc_parse_options(char *options, struct pid_namespace *pid) 38 { 39 char *p; 40 substring_t args[MAX_OPT_ARGS]; 41 int option; 42 43 if (!options) 44 return 1; 45 46 while ((p = strsep(&options, ",")) != NULL) { 47 int token; 48 if (!*p) 49 continue; 50 51 args[0].to = args[0].from = NULL; 52 token = match_token(p, tokens, args); 53 switch (token) { 54 case Opt_gid: 55 if (match_int(&args[0], &option)) 56 return 0; 57 pid->pid_gid = make_kgid(current_user_ns(), option); 58 break; 59 case Opt_hidepid: 60 if (match_int(&args[0], &option)) 61 return 0; 62 if (option < HIDEPID_OFF || 63 option > HIDEPID_INVISIBLE) { 64 pr_err("proc: hidepid value must be between 0 and 2.\n"); 65 return 0; 66 } 67 pid->hide_pid = option; 68 break; 69 default: 70 pr_err("proc: unrecognized mount option \"%s\" " 71 "or missing value\n", p); 72 return 0; 73 } 74 } 75 76 return 1; 77 } 78 79 int proc_remount(struct super_block *sb, int *flags, char *data) 80 { 81 struct pid_namespace *pid = sb->s_fs_info; 82 83 sync_filesystem(sb); 84 return !proc_parse_options(data, pid); 85 } 86 87 static struct dentry *proc_mount(struct file_system_type *fs_type, 88 int flags, const char *dev_name, void *data) 89 { 90 struct pid_namespace *ns; 91 92 if (flags & MS_KERNMOUNT) { 93 ns = data; 94 data = NULL; 95 } else { 96 ns = task_active_pid_ns(current); 97 } 98 99 return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super); 100 } 101 102 static void proc_kill_sb(struct super_block *sb) 103 { 104 struct pid_namespace *ns; 105 106 ns = (struct pid_namespace *)sb->s_fs_info; 107 if (ns->proc_self) 108 dput(ns->proc_self); 109 if (ns->proc_thread_self) 110 dput(ns->proc_thread_self); 111 kill_anon_super(sb); 112 put_pid_ns(ns); 113 } 114 115 static struct file_system_type proc_fs_type = { 116 .name = "proc", 117 .mount = proc_mount, 118 .kill_sb = proc_kill_sb, 119 .fs_flags = FS_USERNS_MOUNT, 120 }; 121 122 void __init proc_root_init(void) 123 { 124 int err; 125 126 proc_init_inodecache(); 127 set_proc_pid_nlink(); 128 err = register_filesystem(&proc_fs_type); 129 if (err) 130 return; 131 132 proc_self_init(); 133 proc_thread_self_init(); 134 proc_symlink("mounts", NULL, "self/mounts"); 135 136 proc_net_init(); 137 138 #ifdef CONFIG_SYSVIPC 139 proc_mkdir("sysvipc", NULL); 140 #endif 141 proc_mkdir("fs", NULL); 142 proc_mkdir("driver", NULL); 143 proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */ 144 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) 145 /* just give it a mountpoint */ 146 proc_create_mount_point("openprom"); 147 #endif 148 proc_tty_init(); 149 proc_mkdir("bus", NULL); 150 proc_sys_init(); 151 } 152 153 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat 154 ) 155 { 156 generic_fillattr(d_inode(dentry), stat); 157 stat->nlink = proc_root.nlink + nr_processes(); 158 return 0; 159 } 160 161 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags) 162 { 163 if (!proc_pid_lookup(dir, dentry, flags)) 164 return NULL; 165 166 return proc_lookup(dir, dentry, flags); 167 } 168 169 static int proc_root_readdir(struct file *file, struct dir_context *ctx) 170 { 171 if (ctx->pos < FIRST_PROCESS_ENTRY) { 172 int error = proc_readdir(file, ctx); 173 if (unlikely(error <= 0)) 174 return error; 175 ctx->pos = FIRST_PROCESS_ENTRY; 176 } 177 178 return proc_pid_readdir(file, ctx); 179 } 180 181 /* 182 * The root /proc directory is special, as it has the 183 * <pid> directories. Thus we don't use the generic 184 * directory handling functions for that.. 185 */ 186 static const struct file_operations proc_root_operations = { 187 .read = generic_read_dir, 188 .iterate_shared = proc_root_readdir, 189 .llseek = generic_file_llseek, 190 }; 191 192 /* 193 * proc root can do almost nothing.. 194 */ 195 static const struct inode_operations proc_root_inode_operations = { 196 .lookup = proc_root_lookup, 197 .getattr = proc_root_getattr, 198 }; 199 200 /* 201 * This is the root "inode" in the /proc tree.. 202 */ 203 struct proc_dir_entry proc_root = { 204 .low_ino = PROC_ROOT_INO, 205 .namelen = 5, 206 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 207 .nlink = 2, 208 .count = ATOMIC_INIT(1), 209 .proc_iops = &proc_root_inode_operations, 210 .proc_fops = &proc_root_operations, 211 .parent = &proc_root, 212 .subdir = RB_ROOT, 213 .name = "/proc", 214 }; 215 216 int pid_ns_prepare_proc(struct pid_namespace *ns) 217 { 218 struct vfsmount *mnt; 219 220 mnt = kern_mount_data(&proc_fs_type, ns); 221 if (IS_ERR(mnt)) 222 return PTR_ERR(mnt); 223 224 ns->proc_mnt = mnt; 225 return 0; 226 } 227 228 void pid_ns_release_proc(struct pid_namespace *ns) 229 { 230 kern_unmount(ns->proc_mnt); 231 } 232