zdtm/memfd04: check that execveat works on memfd when it has a mapping

Signed-off-by: Andrei Vagin <[email protected]>

test/zdtm/static/memfd04.c

@@ -1,4 +1,5 @@
 #include <linux/memfd.h>
+#include <sys/mman.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -73,20 +74,27 @@ static const size_t script_len = sizeof(script) - 1;
 
 int main(int argc, char *argv[])
 {
+	char *addr;
 	int fd;
 
 	test_init(argc, argv);
 
 	fd = _memfd_create("somename", 0);
 	if (fd < 0) {
-		fail("memfd_create()");
+		pr_perror("memfd_create()");
+		return 1;
+	}
+	if (ftruncate(fd, script_len) == -1) {
+		pr_perror("ftruncate");
 		return 1;
 	}
 
-	if (write(fd, script, script_len) != script_len) {
-		fail("write(memfd)");
+	addr = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, fd, 0);
+	if (addr == MAP_FAILED) {
+		pr_perror("mmap");
 		return 1;
 	}
+	memcpy(addr, script, script_len);
 
 	if (!test_exec_fd(fd))
 		return 1;