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#include <stdint.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "zdtmtst.h"
#ifndef MAP_DROPPABLE
#define MAP_DROPPABLE 0x08
#endif
#ifndef MADV_WIPEONFORK
#define MADV_WIPEONFORK 18
#endif
const char *test_doc = "Test MAP_DROPPABLE/MADV_WIPEONFORK mappings with 2 processes";
const char *test_author = "Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>";
bool mem_is_zero(const uint8_t *buffer, size_t length)
{
size_t i;
for (i = 0; i < length; i++)
if (buffer[i] != 0)
return false;
return true;
}
int main(int argc, char **argv)
{
uint8_t *p1, *p2;
pid_t pid;
int status;
const char data[] = "MADV_WIPEONFORK vma data";
bool criu_was_there = false;
struct stat st1, st2;
test_init(argc, argv);
p1 = mmap(NULL, sizeof(data), PROT_READ | PROT_WRITE,
MAP_DROPPABLE | MAP_ANONYMOUS, 0, 0);
if (p1 == MAP_FAILED) {
if (errno == EINVAL) {
skip("mmap failed, no kernel support for MAP_DROPPABLE\n");
goto skip;
} else {
pr_perror("mmap failed");
return -1;
}
}
p2 = mmap(NULL, sizeof(data), PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
if (p2 == MAP_FAILED) {
pr_perror("mmap failed");
return 1;
}
if (madvise(p2, sizeof(data), MADV_WIPEONFORK)) {
pr_perror("madvise failed");
return -1;
}
/* contents of this mapping is supposed to be dropped after C/R */
memcpy(p1, data, sizeof(data));
/* contents of this mapping is supposed to be dropped after fork() */
memcpy(p2, data, sizeof(data));
/*
* Let's spawn a process before C/R so our mappings get inherited
* then, after C/R we need to ensure that CRIU memory premapping
* machinery works properly.
*
* It is important, because we restore MADV_WIPEONFORK on a later
* stages (after vma premapping happens) and we need to ensure that
* CRIU handles everything in a right way.
*/
pid = test_fork();
if (pid < 0) {
pr_perror("fork failed");
return 1;
}
if (pid == 0) {
test_waitsig();
/*
* Both mappings have VM_WIPEONFORK flag set,
* so we expect to have it null-ified after fork().
*/
if (!mem_is_zero(p1, sizeof(data)) ||
!mem_is_zero(p2, sizeof(data))) {
pr_err("1st child: memory check failed\n");
return 1;
}
return 0;
}
/*
* A simple way to detect if C/R happened is to compare st_ino
* fields of stat() on the procfs files of the current task.
*
* Hopefully, this terrible hack is never used in real-world
* applications ;-) Here, we only need this to make test
* to pass with/without --nocr option.
*/
if (stat("/proc/self/status", &st1)) {
pr_perror("stat");
return 1;
}
test_daemon();
test_waitsig();
/* signal a child process to continue */
if (kill(pid, SIGTERM)) {
pr_perror("kill");
goto err;
}
if (waitpid(pid, &status, 0) != pid) {
pr_perror("1st waitpid");
goto err;
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
fail("1st process didn't exit cleanly: status=%d", status);
goto err;
}
if (stat("/proc/self/status", &st2)) {
pr_perror("stat");
return 1;
}
/* detect CRIU */
criu_was_there = st1.st_ino != st2.st_ino;
/*
* We should mark failure if one of the following happens:
* 1. MAP_DROPPABLE memory is not zero after C/R
* 2. MAP_DROPPABLE memory somehow changed without C/R
* (kernel issue? memory pressure?)
* 3. MADV_WIPEONFORK memory is not preserved
*
* We care about 2nd case only because we would like test
* to pass even with --nocr zdtm.py option.
*/
if ((criu_was_there && !mem_is_zero(p1, sizeof(data))) ||
(!criu_was_there && memcmp(p1, data, sizeof(data))) ||
memcmp(p2, data, sizeof(data))) {
fail("Data mismatch");
return 1;
}
/* contents of these mappings is supposed to be dropped after fork() */
memcpy(p1, data, sizeof(data));
memcpy(p2, data, sizeof(data));
pid = test_fork();
if (pid < 0) {
pr_perror("fork failed");
return 1;
}
if (pid == 0) {
if (!mem_is_zero(p1, sizeof(data)) ||
!mem_is_zero(p2, sizeof(data))) {
pr_err("2nd child: memory check failed\n");
return 1;
}
return 0;
}
if (waitpid(pid, &status, 0) != pid) {
pr_perror("2nd waitpid");
goto err;
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
fail("2nd process didn't exit cleanly: status=%d", status);
goto err;
}
pass();
return 0;
err:
if (waitpid(-1, NULL, WNOHANG) == 0) {
kill(pid, SIGTERM);
wait(NULL);
}
return 1;
skip:
test_daemon();
test_waitsig();
pass();
return 0;
}
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