zdtm: check that process w/o file descriptors can be dumped and restored

In addition it checks that criu closes all its descriptors

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/live/static/Makefile

@@ -115,6 +115,7 @@ TST_NOFILE	=				\
 		dumpable01			\
 		dumpable02			\
 		remap_dead_pid			\
+		fd				\
 #		jobctl00			\
 
 TST_FILE	=				\

test/zdtm/live/static/fd.c

@@ -0,0 +1,109 @@
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <string.h>
+#include <sys/wait.h>
+
+#include "zdtmtst.h"
+#include "lock.h"
+
+const char *test_doc	= "Check that criu closes up all its descriptors";
+const char *test_author	= "Andrew Vagin <avagin@parallels.com>";
+
+int main(int argc, char **argv)
+{
+	struct dirent *de;
+	char pfd[PATH_MAX];
+	mutex_t *lock;
+	int status;
+	pid_t pid;
+	DIR *d;
+
+	test_init(argc, argv);
+
+	lock = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (lock == MAP_FAILED)
+		return 1;
+
+	mutex_init(lock);
+	mutex_lock(lock);
+
+	pid = fork();
+	if (pid < 0) {
+		err("fork()");
+		return 1;
+	}
+
+	if (pid == 0) {
+
+		d = opendir("/proc/self/fd");
+		if (d == NULL)
+			return 1;
+
+		while ((de = readdir(d))) {
+			int fd;
+
+			if (de->d_name[0] == '.')
+				continue;
+
+			fd = atoi(de->d_name);
+			if (dirfd(d) == fd)
+				continue;
+			close(fd);
+		}
+
+		closedir(d);
+		mutex_unlock(lock);
+
+		test_waitsig();
+
+		return 0;
+	}
+
+	mutex_lock(lock);
+
+	test_daemon();
+	test_waitsig();
+
+	snprintf(pfd, sizeof(pfd), "/proc/%d/fd", pid);
+	d = opendir(pfd);
+	if (d == NULL)
+		return 2;
+
+	while ((de = readdir(d))) {
+		int ret;
+
+		if (de->d_name[0] == '.')
+			continue;
+
+		ret = readlinkat(dirfd(d), de->d_name, pfd, sizeof(pfd) - 1);
+		if (ret < 0) {
+			err("readlink");
+			ret = 0;
+		}
+		pfd[ret] = '\0';
+		fail("Unexpected fd: %s -> %s\n", de->d_name, pfd);
+		return 1;
+	}
+
+	closedir(d);
+	kill(pid, SIGTERM);
+
+	if (waitpid(pid, &status, 0) != pid) {
+		err("waitpid()");
+		return 1;
+	}
+
+	if (status != 0) {
+		fail("%d:%d:%d:%d", WIFEXITED(status), WEXITSTATUS(status),
+					WIFSIGNALED(status), WTERMSIG(status));
+		return 1;
+	}
+
+	pass();
+
+	return 0;
+}