test/zdtm/static: add maps11 test for MAP_DROPPABLE/MADV_WIPEONFORK

In this test we want to ensure that contents of droppable mappings
and mappings with MADV_WIPEONFORK is properly restored in
parent/child processes.

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

Author: mihalicyn

test/zdtm/static/Makefile

@@ -150,6 +150,7 @@ TST_NOFILE	:=				\
 		maps05				\
 		maps09				\
 		maps10				\
+		maps11				\
 		mlock_setuid			\
 		xids00				\
 		groups				\

test/zdtm/static/maps11.c

@@ -0,0 +1,112 @@
+#include <stdint.h>
+#include <signal.h>
+#include <sys/mman.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>";
+
+int main(int argc, char **argv)
+{
+	uint8_t *p1, *p2;
+	task_waiter_t t;
+	pid_t pid;
+	int status;
+	const char data[] = "MADV_WIPEONFORK vma data";
+
+	test_init(argc, argv);
+	task_waiter_init(&t);
+
+	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;
+	}
+
+	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) {
+		task_waiter_complete(&t, 1);
+		test_waitsig();
+
+		/*
+		 * MAP_DROPPABLE mappings have VM_WIPEONFORK flag set,
+		 * so we expect to have it null-ified after fork().
+		 */
+		if (*p1 != 0)
+			return 1;
+
+		if (*p2 != 0)
+			return 1;
+
+		return 0;
+	}
+
+	task_waiter_wait4(&t, 1);
+
+	test_daemon();
+	test_waitsig();
+
+	kill(pid, SIGTERM);
+	wait(&status);
+	if (WIFEXITED(status)) {
+		if (WEXITSTATUS(status))
+			goto err;
+	} else {
+		goto err;
+	}
+
+	if (memcmp(p1, data, sizeof(data)) || memcmp(p2, data, sizeof(data))) {
+		fail("Data mismatch");
+		return 1;
+	}
+
+	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;
+}