1 | /* |
2 | * Copyright (c) 2021 Alexey Dobriyan <adobriyan@gmail.com> |
3 | * |
4 | * Permission to use, copy, modify, and distribute this software for any |
5 | * purpose with or without fee is hereby granted, provided that the above |
6 | * copyright notice and this permission notice appear in all copies. |
7 | * |
8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
15 | */ |
16 | /* |
17 | * Test that "mount -t proc -o subset=pid" hides everything but pids, |
18 | * /proc/self and /proc/thread-self. |
19 | */ |
20 | #undef NDEBUG |
21 | #include <assert.h> |
22 | #include <errno.h> |
23 | #include <sched.h> |
24 | #include <stdbool.h> |
25 | #include <stdlib.h> |
26 | #include <string.h> |
27 | #include <sys/mount.h> |
28 | #include <sys/types.h> |
29 | #include <sys/stat.h> |
30 | #include <fcntl.h> |
31 | #include <dirent.h> |
32 | #include <unistd.h> |
33 | #include <stdio.h> |
34 | |
35 | static inline bool streq(const char *a, const char *b) |
36 | { |
37 | return strcmp(a, b) == 0; |
38 | } |
39 | |
40 | static void make_private_proc(void) |
41 | { |
42 | if (unshare(CLONE_NEWNS) == -1) { |
43 | if (errno == ENOSYS || errno == EPERM) { |
44 | exit(4); |
45 | } |
46 | exit(1); |
47 | } |
48 | if (mount(NULL, "/" , NULL, MS_PRIVATE|MS_REC, NULL) == -1) { |
49 | exit(1); |
50 | } |
51 | if (mount(NULL, "/proc" , "proc" , 0, "subset=pid" ) == -1) { |
52 | exit(1); |
53 | } |
54 | } |
55 | |
56 | static bool string_is_pid(const char *s) |
57 | { |
58 | while (1) { |
59 | switch (*s++) { |
60 | case '0':case '1':case '2':case '3':case '4': |
61 | case '5':case '6':case '7':case '8':case '9': |
62 | continue; |
63 | |
64 | case '\0': |
65 | return true; |
66 | |
67 | default: |
68 | return false; |
69 | } |
70 | } |
71 | } |
72 | |
73 | int main(void) |
74 | { |
75 | make_private_proc(); |
76 | |
77 | DIR *d = opendir("/proc" ); |
78 | assert(d); |
79 | |
80 | struct dirent *de; |
81 | |
82 | bool dot = false; |
83 | bool dot_dot = false; |
84 | bool self = false; |
85 | bool thread_self = false; |
86 | |
87 | while ((de = readdir(d))) { |
88 | if (streq(de->d_name, "." )) { |
89 | assert(!dot); |
90 | dot = true; |
91 | assert(de->d_type == DT_DIR); |
92 | } else if (streq(de->d_name, ".." )) { |
93 | assert(!dot_dot); |
94 | dot_dot = true; |
95 | assert(de->d_type == DT_DIR); |
96 | } else if (streq(de->d_name, "self" )) { |
97 | assert(!self); |
98 | self = true; |
99 | assert(de->d_type == DT_LNK); |
100 | } else if (streq(de->d_name, "thread-self" )) { |
101 | assert(!thread_self); |
102 | thread_self = true; |
103 | assert(de->d_type == DT_LNK); |
104 | } else { |
105 | if (!string_is_pid(de->d_name)) { |
106 | fprintf(stderr, "d_name '%s'\n" , de->d_name); |
107 | assert(0); |
108 | } |
109 | assert(de->d_type == DT_DIR); |
110 | } |
111 | } |
112 | |
113 | char c; |
114 | int rv = readlink("/proc/cpuinfo" , &c, 1); |
115 | assert(rv == -1 && errno == ENOENT); |
116 | |
117 | int fd = open("/proc/cpuinfo" , O_RDONLY); |
118 | assert(fd == -1 && errno == ENOENT); |
119 | |
120 | return 0; |
121 | } |
122 | |