LXR linux/tools/testing/selftests/nsfs/pidns.c

   1#define _GNU_SOURCE
   2#include <sched.h>
   3#include <unistd.h>
   4#include <stdio.h>
   5#include <stdlib.h>
   6#include <signal.h>
   7#include <errno.h>
   8#include <sys/types.h>
   9#include <sys/stat.h>
  10#include <fcntl.h>
  11#include <sys/ioctl.h>
  12#include <sys/prctl.h>
  13#include <sys/wait.h>
  14
  15#define pr_err(fmt, ...) \
  16                ({ \
  17                        fprintf(stderr, "%s:%d:" fmt ": %m\n", \
  18                                __func__, __LINE__, ##__VA_ARGS__); \
  19                        1; \
  20                })
  21
  22#define NSIO    0xb7
  23#define NS_GET_USERNS   _IO(NSIO, 0x1)
  24#define NS_GET_PARENT   _IO(NSIO, 0x2)
  25
  26#define __stack_aligned__       __attribute__((aligned(16)))
  27struct cr_clone_arg {
  28        char stack[128] __stack_aligned__;
  29        char stack_ptr[0];
  30};
  31
  32static int child(void *args)
  33{
  34        prctl(PR_SET_PDEATHSIG, SIGKILL);
  35        while (1)
  36                sleep(1);
  37        exit(0);
  38}
  39
  40int main(int argc, char *argv[])
  41{
  42        char *ns_strs[] = {"pid", "user"};
  43        char path[] = "/proc/0123456789/ns/pid";
  44        struct cr_clone_arg ca;
  45        struct stat st1, st2;
  46        int ns, pns, i;
  47        pid_t pid;
  48
  49        pid = clone(child, ca.stack_ptr, CLONE_NEWUSER | CLONE_NEWPID | SIGCHLD, NULL);
  50        if (pid < 0)
  51                return pr_err("clone");
  52
  53        for (i = 0; i < 2; i++) {
  54                snprintf(path, sizeof(path), "/proc/%d/ns/%s", pid, ns_strs[i]);
  55                ns = open(path, O_RDONLY);
  56                if (ns < 0)
  57                        return pr_err("Unable to open %s", path);
  58
  59                pns = ioctl(ns, NS_GET_PARENT);
  60                if (pns < 0)
  61                        return pr_err("Unable to get a parent pidns");
  62
  63                snprintf(path, sizeof(path), "/proc/self/ns/%s", ns_strs[i]);
  64                if (stat(path, &st2))
  65                        return pr_err("Unable to stat %s", path);
  66                if (fstat(pns, &st1))
  67                        return pr_err("Unable to stat the parent pidns");
  68                if (st1.st_ino != st2.st_ino)
  69                        return pr_err("NS_GET_PARENT returned a wrong namespace");
  70
  71                if (ioctl(pns, NS_GET_PARENT) >= 0 || errno != EPERM)
  72                        return pr_err("Don't get EPERM");;
  73        }
  74
  75        kill(pid, SIGKILL);
  76        wait(NULL);
  77        return 0;
  78}
  79