zdtm: test execveat(memfd)

Signed-off-by: Michał Mirosław <emmir@google.com>

test/zdtm/static/Makefile

@@ -258,6 +258,7 @@ TST_NOFILE	:=				\
 		memfd02				\
 		memfd02-hugetlb			\
 		memfd03				\
+		memfd04				\
 		shmemfd				\
 		shmemfd-priv			\
 		time				\

test/zdtm/static/memfd04.c

@@ -0,0 +1,105 @@
+#include <linux/memfd.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc = "exec(memfd)";
+const char *test_author = "Michał Mirosław <emmir@google.com>";
+
+static int _memfd_create(const char *name, unsigned int flags)
+{
+	return syscall(SYS_memfd_create, name, flags);
+}
+
+static int _execveat(int dirfd, const char *pathname, const char *const argv[], const char *const envp[], int flags)
+{
+	return syscall(SYS_execveat, dirfd, pathname, argv, envp, flags);
+}
+
+static const char *const script_argv[] = { "true", NULL };
+static const char *const script_env[] = { NULL };
+
+static bool test_exec_fd(int fd)
+{
+	int err, pid, status;
+
+	err = fcntl(fd, F_GETFD);
+	if (err < 0) {
+		fail("fcntl(F_GETFD)");
+		return false;
+	}
+	if (err) {
+		errno = 0;
+		fail("F_GETFD for the memfd returned %d but expected 0", err);
+		return false;
+	}
+
+	pid = fork();
+	if (!pid) {
+		_execveat(fd, "", script_argv, script_env, AT_EMPTY_PATH);
+		err = errno;
+		pr_perror("execveat()");
+		_exit(err);
+	}
+
+	if (pid < 0) {
+		fail("fork()");
+		return false;
+	}
+
+	while (waitpid(pid, &status, 0) != pid) {
+		if (errno == EINTR)
+			continue;
+		fail("waitpid(child=%d)", pid);
+		return false;
+	}
+
+	if (status != 0) {
+		pr_err("child exited with status=%d\n", status);
+		return false;
+	}
+
+	return true;
+}
+
+static const char script[] = "#!/bin/true";
+static const size_t script_len = sizeof(script) - 1;
+
+int main(int argc, char *argv[])
+{
+	int fd;
+
+	test_init(argc, argv);
+
+	fd = _memfd_create("somename", 0);
+	if (fd < 0) {
+		fail("memfd_create()");
+		return 1;
+	}
+
+	if (write(fd, script, script_len) != script_len) {
+		fail("write(memfd)");
+		return 1;
+	}
+
+	if (!test_exec_fd(fd))
+		return 1;
+
+	test_msg("execveat(memfd) succeeded before C/R.\n");
+
+	test_daemon();
+	test_waitsig();
+
+	if (!test_exec_fd(fd))
+		return 1;
+
+	pass();
+
+	return 0;
+}

test/zdtm/static/memfd04.desc

@@ -0,0 +1 @@
+{'deps': ['/bin/true']}