vfork_exec.c

  1// SPDX-License-Identifier: GPL-2.0
  2#define _GNU_SOURCE
  3#include <errno.h>
  4#include <fcntl.h>
  5#include <sched.h>
  6#include <stdio.h>
  7#include <stdbool.h>
  8#include <sys/stat.h>
  9#include <sys/syscall.h>
 10#include <sys/types.h>
 11#include <sys/wait.h>
 12#include <time.h>
 13#include <unistd.h>
 14#include <string.h>
 15#include <pthread.h>
 16
 17#include "log.h"
 18#include "timens.h"
 19
 20#define OFFSET (36000)
 21
 22struct thread_args {
 23	char *tst_name;
 24	struct timespec *now;
 25};
 26
 27static void *tcheck(void *_args)
 28{
 29	struct thread_args *args = _args;
 30	struct timespec *now = args->now, tst;
 31	int i;
 32
 33	for (i = 0; i < 2; i++) {
 34		_gettime(CLOCK_MONOTONIC, &tst, i);
 35		if (labs(tst.tv_sec - now->tv_sec) > 5) {
 36			pr_fail("%s: in-thread: unexpected value: %ld (%ld)\n",
 37				args->tst_name, tst.tv_sec, now->tv_sec);
 38			return (void *)1UL;
 39		}
 40	}
 41	return NULL;
 42}
 43
 44static int check_in_thread(char *tst_name, struct timespec *now)
 45{
 46	struct thread_args args = {
 47		.tst_name = tst_name,
 48		.now = now,
 49	};
 50	pthread_t th;
 51	void *retval;
 52
 53	if (pthread_create(&th, NULL, tcheck, &args))
 54		return pr_perror("thread");
 55	if (pthread_join(th, &retval))
 56		return pr_perror("pthread_join");
 57	return !(retval == NULL);
 58}
 59
 60static int check(char *tst_name, struct timespec *now)
 61{
 62	struct timespec tst;
 63	int i;
 64
 65	for (i = 0; i < 2; i++) {
 66		_gettime(CLOCK_MONOTONIC, &tst, i);
 67		if (labs(tst.tv_sec - now->tv_sec) > 5)
 68			return pr_fail("%s: unexpected value: %ld (%ld)\n",
 69					tst_name, tst.tv_sec, now->tv_sec);
 70	}
 71	if (check_in_thread(tst_name, now))
 72		return 1;
 73	ksft_test_result_pass("%s\n", tst_name);
 74	return 0;
 75}
 76
 77int main(int argc, char *argv[])
 78{
 79	struct timespec now;
 80	int status;
 81	pid_t pid;
 82
 83	if (argc > 1) {
 84		char *endptr;
 85
 86		ksft_cnt.ksft_pass = 1;
 87		now.tv_sec = strtoul(argv[1], &endptr, 0);
 88		if (*endptr != 0)
 89			return pr_perror("strtoul");
 90
 91		return check("child after exec", &now);
 92	}
 93
 94	ksft_print_header();
 95
 96	nscheck();
 97
 98	ksft_set_plan(4);
 99
100	clock_gettime(CLOCK_MONOTONIC, &now);
101
102	if (unshare_timens())
103		return 1;
104
105	if (_settime(CLOCK_MONOTONIC, OFFSET))
106		return 1;
107
108	if (check("parent before vfork", &now))
109		return 1;
110
111	pid = vfork();
112	if (pid < 0)
113		return pr_perror("fork");
114
115	if (pid == 0) {
116		char now_str[64];
117		char *cargv[] = {"exec", now_str, NULL};
118		char *cenv[] = {NULL};
119
120		/* Check for proper vvar offsets after execve. */
121		snprintf(now_str, sizeof(now_str), "%ld", now.tv_sec + OFFSET);
122		execve("/proc/self/exe", cargv, cenv);
123		pr_perror("execve");
124		_exit(1);
125	}
126
127	if (waitpid(pid, &status, 0) != pid)
128		return pr_perror("waitpid");
129
130	if (status)
131		ksft_exit_fail();
132	ksft_inc_pass_cnt();
133	ksft_test_result_pass("wait for child\n");
134
135	/* Check that we are still in the source timens. */
136	if (check("parent after vfork", &now))
137		return 1;
138
139	ksft_exit_pass();
140	return 0;
141}