Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
1da177e4 | 15 | #include <linux/init.h> |
914e2637 | 16 | #include <linux/sched.h> |
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/bitops.h> | |
87a8ebd6 | 19 | #include <linux/user_namespace.h> |
f6c7a1f3 | 20 | #include <linux/mount.h> |
07543f5c | 21 | #include <linux/pid_namespace.h> |
97412950 | 22 | #include <linux/parser.h> |
1da177e4 | 23 | |
fee781e6 AB |
24 | #include "internal.h" |
25 | ||
07543f5c PE |
26 | static int proc_test_super(struct super_block *sb, void *data) |
27 | { | |
28 | return sb->s_fs_info == data; | |
29 | } | |
30 | ||
31 | static int proc_set_super(struct super_block *sb, void *data) | |
32 | { | |
ff78fca2 AV |
33 | int err = set_anon_super(sb, NULL); |
34 | if (!err) { | |
35 | struct pid_namespace *ns = (struct pid_namespace *)data; | |
36 | sb->s_fs_info = get_pid_ns(ns); | |
37 | } | |
38 | return err; | |
07543f5c PE |
39 | } |
40 | ||
97412950 | 41 | enum { |
0499680a | 42 | Opt_gid, Opt_hidepid, Opt_err, |
97412950 VK |
43 | }; |
44 | ||
45 | static const match_table_t tokens = { | |
0499680a VK |
46 | {Opt_hidepid, "hidepid=%u"}, |
47 | {Opt_gid, "gid=%u"}, | |
97412950 VK |
48 | {Opt_err, NULL}, |
49 | }; | |
50 | ||
51 | static int proc_parse_options(char *options, struct pid_namespace *pid) | |
52 | { | |
53 | char *p; | |
54 | substring_t args[MAX_OPT_ARGS]; | |
0499680a | 55 | int option; |
97412950 VK |
56 | |
57 | if (!options) | |
58 | return 1; | |
59 | ||
60 | while ((p = strsep(&options, ",")) != NULL) { | |
61 | int token; | |
62 | if (!*p) | |
63 | continue; | |
64 | ||
9fb88442 | 65 | args[0].to = args[0].from = NULL; |
97412950 VK |
66 | token = match_token(p, tokens, args); |
67 | switch (token) { | |
0499680a VK |
68 | case Opt_gid: |
69 | if (match_int(&args[0], &option)) | |
70 | return 0; | |
dcb0f222 | 71 | pid->pid_gid = make_kgid(current_user_ns(), option); |
0499680a VK |
72 | break; |
73 | case Opt_hidepid: | |
74 | if (match_int(&args[0], &option)) | |
75 | return 0; | |
76 | if (option < 0 || option > 2) { | |
77 | pr_err("proc: hidepid value must be between 0 and 2.\n"); | |
78 | return 0; | |
79 | } | |
80 | pid->hide_pid = option; | |
81 | break; | |
97412950 VK |
82 | default: |
83 | pr_err("proc: unrecognized mount option \"%s\" " | |
84 | "or missing value\n", p); | |
85 | return 0; | |
86 | } | |
87 | } | |
88 | ||
89 | return 1; | |
90 | } | |
91 | ||
92 | int proc_remount(struct super_block *sb, int *flags, char *data) | |
93 | { | |
94 | struct pid_namespace *pid = sb->s_fs_info; | |
02b9984d TT |
95 | |
96 | sync_filesystem(sb); | |
97412950 VK |
97 | return !proc_parse_options(data, pid); |
98 | } | |
99 | ||
aed1d84f AV |
100 | static struct dentry *proc_mount(struct file_system_type *fs_type, |
101 | int flags, const char *dev_name, void *data) | |
1da177e4 | 102 | { |
07543f5c PE |
103 | int err; |
104 | struct super_block *sb; | |
105 | struct pid_namespace *ns; | |
97412950 | 106 | char *options; |
07543f5c | 107 | |
97412950 | 108 | if (flags & MS_KERNMOUNT) { |
07543f5c | 109 | ns = (struct pid_namespace *)data; |
97412950 VK |
110 | options = NULL; |
111 | } else { | |
17cf22c3 | 112 | ns = task_active_pid_ns(current); |
97412950 | 113 | options = data; |
87a8ebd6 | 114 | |
e51db735 EB |
115 | /* Does the mounter have privilege over the pid namespace? */ |
116 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) | |
87a8ebd6 | 117 | return ERR_PTR(-EPERM); |
97412950 | 118 | } |
07543f5c | 119 | |
9249e17f | 120 | sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns); |
07543f5c | 121 | if (IS_ERR(sb)) |
aed1d84f | 122 | return ERR_CAST(sb); |
07543f5c | 123 | |
e54ad7f1 JH |
124 | /* |
125 | * procfs isn't actually a stacking filesystem; however, there is | |
126 | * too much magic going on inside it to permit stacking things on | |
127 | * top of it | |
128 | */ | |
129 | sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; | |
130 | ||
99663be7 VK |
131 | if (!proc_parse_options(options, ns)) { |
132 | deactivate_locked_super(sb); | |
133 | return ERR_PTR(-EINVAL); | |
134 | } | |
135 | ||
07543f5c | 136 | if (!sb->s_root) { |
07543f5c PE |
137 | err = proc_fill_super(sb); |
138 | if (err) { | |
6f5bbff9 | 139 | deactivate_locked_super(sb); |
aed1d84f | 140 | return ERR_PTR(err); |
07543f5c PE |
141 | } |
142 | ||
07543f5c | 143 | sb->s_flags |= MS_ACTIVE; |
90f8572b EB |
144 | /* User space would break if executables appear on proc */ |
145 | sb->s_iflags |= SB_I_NOEXEC; | |
07543f5c PE |
146 | } |
147 | ||
aed1d84f | 148 | return dget(sb->s_root); |
07543f5c PE |
149 | } |
150 | ||
151 | static void proc_kill_sb(struct super_block *sb) | |
152 | { | |
153 | struct pid_namespace *ns; | |
154 | ||
155 | ns = (struct pid_namespace *)sb->s_fs_info; | |
021ada7d AV |
156 | if (ns->proc_self) |
157 | dput(ns->proc_self); | |
0097875b EB |
158 | if (ns->proc_thread_self) |
159 | dput(ns->proc_thread_self); | |
07543f5c PE |
160 | kill_anon_super(sb); |
161 | put_pid_ns(ns); | |
1da177e4 LT |
162 | } |
163 | ||
c2319540 | 164 | static struct file_system_type proc_fs_type = { |
1da177e4 | 165 | .name = "proc", |
aed1d84f | 166 | .mount = proc_mount, |
07543f5c | 167 | .kill_sb = proc_kill_sb, |
1b852bce | 168 | .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT, |
1da177e4 LT |
169 | }; |
170 | ||
1da177e4 LT |
171 | void __init proc_root_init(void) |
172 | { | |
5bcd7ff9 AD |
173 | int err; |
174 | ||
175 | proc_init_inodecache(); | |
1da177e4 LT |
176 | err = register_filesystem(&proc_fs_type); |
177 | if (err) | |
178 | return; | |
07543f5c | 179 | |
e656d8a6 | 180 | proc_self_init(); |
0097875b | 181 | proc_thread_self_init(); |
155134fe | 182 | proc_symlink("mounts", NULL, "self/mounts"); |
457c4cbc EB |
183 | |
184 | proc_net_init(); | |
1da177e4 LT |
185 | |
186 | #ifdef CONFIG_SYSVIPC | |
187 | proc_mkdir("sysvipc", NULL); | |
1da177e4 | 188 | #endif |
36a5aeb8 | 189 | proc_mkdir("fs", NULL); |
928b4d8c | 190 | proc_mkdir("driver", NULL); |
eb6d38d5 | 191 | proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */ |
1da177e4 LT |
192 | #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) |
193 | /* just give it a mountpoint */ | |
eb6d38d5 | 194 | proc_create_mount_point("openprom"); |
1da177e4 LT |
195 | #endif |
196 | proc_tty_init(); | |
9c37066d | 197 | proc_mkdir("bus", NULL); |
77b14db5 | 198 | proc_sys_init(); |
1da177e4 LT |
199 | } |
200 | ||
76b6159b AV |
201 | static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat |
202 | ) | |
1da177e4 | 203 | { |
2b0143b5 | 204 | generic_fillattr(d_inode(dentry), stat); |
76b6159b AV |
205 | stat->nlink = proc_root.nlink + nr_processes(); |
206 | return 0; | |
207 | } | |
1da177e4 | 208 | |
00cd8dd3 | 209 | static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags) |
76b6159b | 210 | { |
335eb531 | 211 | if (!proc_pid_lookup(dir, dentry, flags)) |
1da177e4 | 212 | return NULL; |
1da177e4 | 213 | |
335eb531 | 214 | return proc_lookup(dir, dentry, flags); |
1da177e4 LT |
215 | } |
216 | ||
f0c3b509 | 217 | static int proc_root_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 218 | { |
f0c3b509 | 219 | if (ctx->pos < FIRST_PROCESS_ENTRY) { |
94fc5d9d RG |
220 | int error = proc_readdir(file, ctx); |
221 | if (unlikely(error <= 0)) | |
222 | return error; | |
f0c3b509 | 223 | ctx->pos = FIRST_PROCESS_ENTRY; |
1da177e4 | 224 | } |
1da177e4 | 225 | |
f0c3b509 | 226 | return proc_pid_readdir(file, ctx); |
1da177e4 LT |
227 | } |
228 | ||
229 | /* | |
230 | * The root /proc directory is special, as it has the | |
231 | * <pid> directories. Thus we don't use the generic | |
232 | * directory handling functions for that.. | |
233 | */ | |
00977a59 | 234 | static const struct file_operations proc_root_operations = { |
1da177e4 | 235 | .read = generic_read_dir, |
f50752ea AV |
236 | .iterate_shared = proc_root_readdir, |
237 | .llseek = generic_file_llseek, | |
1da177e4 LT |
238 | }; |
239 | ||
240 | /* | |
241 | * proc root can do almost nothing.. | |
242 | */ | |
c5ef1c42 | 243 | static const struct inode_operations proc_root_inode_operations = { |
1da177e4 | 244 | .lookup = proc_root_lookup, |
76b6159b | 245 | .getattr = proc_root_getattr, |
1da177e4 LT |
246 | }; |
247 | ||
248 | /* | |
249 | * This is the root "inode" in the /proc tree.. | |
250 | */ | |
251 | struct proc_dir_entry proc_root = { | |
252 | .low_ino = PROC_ROOT_INO, | |
253 | .namelen = 5, | |
1da177e4 LT |
254 | .mode = S_IFDIR | S_IRUGO | S_IXUGO, |
255 | .nlink = 2, | |
5a622f2d | 256 | .count = ATOMIC_INIT(1), |
1da177e4 LT |
257 | .proc_iops = &proc_root_inode_operations, |
258 | .proc_fops = &proc_root_operations, | |
259 | .parent = &proc_root, | |
710585d4 | 260 | .subdir = RB_ROOT, |
09570f91 | 261 | .name = "/proc", |
1da177e4 LT |
262 | }; |
263 | ||
6f4e6433 PE |
264 | int pid_ns_prepare_proc(struct pid_namespace *ns) |
265 | { | |
266 | struct vfsmount *mnt; | |
267 | ||
268 | mnt = kern_mount_data(&proc_fs_type, ns); | |
269 | if (IS_ERR(mnt)) | |
270 | return PTR_ERR(mnt); | |
271 | ||
579441a3 | 272 | ns->proc_mnt = mnt; |
6f4e6433 PE |
273 | return 0; |
274 | } | |
275 | ||
276 | void pid_ns_release_proc(struct pid_namespace *ns) | |
277 | { | |
905ad269 | 278 | kern_unmount(ns->proc_mnt); |
6f4e6433 | 279 | } |