1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * Copyright © 2019 Alexey Dobriyan <adobriyan@gmail.com>
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Permission to use, copy, modify, and distribute this software for any
5*4882a593Smuzhiyun * purpose with or without fee is hereby granted, provided that the above
6*4882a593Smuzhiyun * copyright notice and this permission notice appear in all copies.
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9*4882a593Smuzhiyun * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10*4882a593Smuzhiyun * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11*4882a593Smuzhiyun * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12*4882a593Smuzhiyun * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13*4882a593Smuzhiyun * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14*4882a593Smuzhiyun * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15*4882a593Smuzhiyun */
16*4882a593Smuzhiyun /*
17*4882a593Smuzhiyun * Test that setns(CLONE_NEWIPC) points to new /proc/sysvipc content even
18*4882a593Smuzhiyun * if old one is in dcache.
19*4882a593Smuzhiyun */
20*4882a593Smuzhiyun #undef NDEBUG
21*4882a593Smuzhiyun #include <assert.h>
22*4882a593Smuzhiyun #include <errno.h>
23*4882a593Smuzhiyun #include <stdio.h>
24*4882a593Smuzhiyun #include <sched.h>
25*4882a593Smuzhiyun #include <signal.h>
26*4882a593Smuzhiyun #include <stdlib.h>
27*4882a593Smuzhiyun #include <string.h>
28*4882a593Smuzhiyun #include <unistd.h>
29*4882a593Smuzhiyun #include <sys/types.h>
30*4882a593Smuzhiyun #include <sys/stat.h>
31*4882a593Smuzhiyun #include <fcntl.h>
32*4882a593Smuzhiyun #include <sys/ipc.h>
33*4882a593Smuzhiyun #include <sys/shm.h>
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun static pid_t pid = -1;
36*4882a593Smuzhiyun
f(void)37*4882a593Smuzhiyun static void f(void)
38*4882a593Smuzhiyun {
39*4882a593Smuzhiyun if (pid > 0) {
40*4882a593Smuzhiyun kill(pid, SIGTERM);
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun
main(void)44*4882a593Smuzhiyun int main(void)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun int fd[2];
47*4882a593Smuzhiyun char _ = 0;
48*4882a593Smuzhiyun int nsfd;
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun atexit(f);
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun /* Check for priviledges and syscall availability straight away. */
53*4882a593Smuzhiyun if (unshare(CLONE_NEWIPC) == -1) {
54*4882a593Smuzhiyun if (errno == ENOSYS || errno == EPERM) {
55*4882a593Smuzhiyun return 4;
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun return 1;
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun /* Distinguisher between two otherwise empty IPC namespaces. */
60*4882a593Smuzhiyun if (shmget(IPC_PRIVATE, 1, IPC_CREAT) == -1) {
61*4882a593Smuzhiyun return 1;
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun if (pipe(fd) == -1) {
65*4882a593Smuzhiyun return 1;
66*4882a593Smuzhiyun }
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun pid = fork();
69*4882a593Smuzhiyun if (pid == -1) {
70*4882a593Smuzhiyun return 1;
71*4882a593Smuzhiyun }
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun if (pid == 0) {
74*4882a593Smuzhiyun if (unshare(CLONE_NEWIPC) == -1) {
75*4882a593Smuzhiyun return 1;
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun if (write(fd[1], &_, 1) != 1) {
79*4882a593Smuzhiyun return 1;
80*4882a593Smuzhiyun }
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun pause();
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun return 0;
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun if (read(fd[0], &_, 1) != 1) {
88*4882a593Smuzhiyun return 1;
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun {
92*4882a593Smuzhiyun char buf[64];
93*4882a593Smuzhiyun snprintf(buf, sizeof(buf), "/proc/%u/ns/ipc", pid);
94*4882a593Smuzhiyun nsfd = open(buf, O_RDONLY);
95*4882a593Smuzhiyun if (nsfd == -1) {
96*4882a593Smuzhiyun return 1;
97*4882a593Smuzhiyun }
98*4882a593Smuzhiyun }
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun /* Reliably pin dentry into dcache. */
101*4882a593Smuzhiyun (void)open("/proc/sysvipc/shm", O_RDONLY);
102*4882a593Smuzhiyun
103*4882a593Smuzhiyun if (setns(nsfd, CLONE_NEWIPC) == -1) {
104*4882a593Smuzhiyun return 1;
105*4882a593Smuzhiyun }
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun kill(pid, SIGTERM);
108*4882a593Smuzhiyun pid = 0;
109*4882a593Smuzhiyun
110*4882a593Smuzhiyun {
111*4882a593Smuzhiyun char buf[4096];
112*4882a593Smuzhiyun ssize_t rv;
113*4882a593Smuzhiyun int fd;
114*4882a593Smuzhiyun
115*4882a593Smuzhiyun fd = open("/proc/sysvipc/shm", O_RDONLY);
116*4882a593Smuzhiyun if (fd == -1) {
117*4882a593Smuzhiyun return 1;
118*4882a593Smuzhiyun }
119*4882a593Smuzhiyun
120*4882a593Smuzhiyun #define S32 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n"
121*4882a593Smuzhiyun #define S64 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n"
122*4882a593Smuzhiyun rv = read(fd, buf, sizeof(buf));
123*4882a593Smuzhiyun if (rv == strlen(S32)) {
124*4882a593Smuzhiyun assert(memcmp(buf, S32, strlen(S32)) == 0);
125*4882a593Smuzhiyun } else if (rv == strlen(S64)) {
126*4882a593Smuzhiyun assert(memcmp(buf, S64, strlen(S64)) == 0);
127*4882a593Smuzhiyun } else {
128*4882a593Smuzhiyun assert(0);
129*4882a593Smuzhiyun }
130*4882a593Smuzhiyun }
131*4882a593Smuzhiyun
132*4882a593Smuzhiyun return 0;
133*4882a593Smuzhiyun }
134