libcriu: enable setting of RPC config file

lib/c/criu.c

@@ -2041,3 +2041,22 @@ void criu_set_empty_ns(int namespaces)
 {
 	criu_local_set_empty_ns(global_opts, namespaces);
 }
+
+int criu_local_set_config_file(criu_opts *opts, const char *path)
+{
+	char *new;
+
+	new = strdup(path);
+	if (!new)
+		return -ENOMEM;
+
+	free(opts->rpc->config_file);
+	opts->rpc->config_file = new;
+
+	return 0;
+}
+
+int criu_set_config_file(const char *path)
+{
+	return criu_local_set_config_file(global_opts, path);
+}

lib/c/criu.h

@@ -116,6 +116,7 @@ void criu_set_pidfd_store_sk(int sk);
 int criu_set_network_lock(enum criu_network_lock_method method);
 int criu_join_ns_add(const char *ns, const char *ns_file, const char *extra_opt);
 void criu_set_mntns_compat_mode(bool val);
+int criu_set_config_file(const char *path);
 
 /*
  * The criu_notify_arg_t na argument is an opaque
@@ -281,6 +282,7 @@ void criu_local_set_pidfd_store_sk(criu_opts *opts, int sk);
 int criu_local_set_network_lock(criu_opts *opts, enum criu_network_lock_method method);
 int criu_local_join_ns_add(criu_opts *opts, const char *ns, const char *ns_file, const char *extra_opt);
 void criu_local_set_mntns_compat_mode(criu_opts *opts, bool val);
+int criu_local_set_config_file(criu_opts *opts, const char *path);
 
 void criu_local_set_notify_cb(criu_opts *opts, int (*cb)(char *action, criu_notify_arg_t na));
 

test/others/libcriu/.gitignore

@@ -8,3 +8,4 @@ test_pre_dump
 test_feature_check
 output/
 libcriu.so.*
+test_rpc_config

test/others/libcriu/Makefile

@@ -3,6 +3,7 @@ include ../../../../criu/Makefile.versions
 TESTS += test_sub
 TESTS += test_self
 TESTS += test_notify
+TESTS += test_rpc_config
 TESTS += test_iters
 TESTS += test_errno
 TESTS += test_join_ns

test/others/libcriu/run.sh

@@ -55,6 +55,7 @@ run_test() {
 run_test test_sub
 run_test test_self
 run_test test_notify
+run_test test_rpc_config
 if [ "$(uname -m)" = "x86_64" ]; then
 	# Skip this on aarch64 as aarch64 has no dirty page tracking
 	run_test test_iters

test/others/libcriu/test_rpc_config.c

@@ -0,0 +1,223 @@
+#include "criu.h"
+#include "lib.h"
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <string.h>
+#include <time.h>
+
+#define RANDOM_NAME_LEN 6
+#define PATH_BUF_SIZE	128
+
+static volatile sig_atomic_t stop = 0;
+static char base_name[RANDOM_NAME_LEN + 1];
+static char log_file[PATH_BUF_SIZE];
+static char conf_file[PATH_BUF_SIZE];
+
+static void handle_signal(int sig)
+{
+	(void)sig;
+	stop = 1;
+}
+
+static void generate_random_base_name(void)
+{
+	const char charset[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+	size_t charset_len;
+	int i;
+
+	charset_len = sizeof(charset) - 1;
+
+	for (i = 0; i < RANDOM_NAME_LEN; i++) {
+		base_name[i] = charset[rand() % charset_len];
+	}
+	base_name[i] = '\0';
+
+	snprintf(log_file, sizeof(log_file), "/tmp/criu-%s.log", base_name);
+	snprintf(conf_file, sizeof(conf_file), "/tmp/criu-%s.conf", base_name);
+}
+
+static int create_criu_config_file(void)
+{
+	int fd;
+	FILE *fp;
+
+	srand(time(NULL));
+	generate_random_base_name();
+
+	fd = open(conf_file, O_CREAT | O_EXCL | O_WRONLY, 0600);
+	if (fd < 0) {
+		perror("Failed to create config file");
+		return -1;
+	}
+
+	fp = fdopen(fd, "w");
+	if (!fp) {
+		perror("fdopen failed");
+		close(fd);
+		unlink(conf_file);
+		return -1;
+	}
+
+	fprintf(fp, "log-file=%s\n", log_file);
+	fflush(fp);
+	fclose(fp);
+
+	return 0;
+}
+
+static int check_log_file(void)
+{
+	struct stat st;
+
+	if (stat(log_file, &st) < 0) {
+		perror("Config file does not exist");
+		return -1;
+	}
+
+	if (st.st_size == 0) {
+		fprintf(stderr, "Config file is empty\n");
+		return -1;
+	}
+
+	unlink(log_file);
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	int pipe_fd[2];
+	pid_t pid;
+	int ret;
+	int child_ret;
+
+	int img_fd = open(argv[2], O_DIRECTORY);
+	if (img_fd < 0) {
+		perror("Failed to open images directory");
+		goto cleanup;
+	}
+
+	if (create_criu_config_file() < 0) {
+		printf("Failed to create config file\n");
+		return EXIT_FAILURE;
+	}
+
+	if (pipe(pipe_fd) < 0) {
+		perror("pipe");
+		return EXIT_FAILURE;
+	}
+
+	pid = fork();
+	if (pid < 0) {
+		perror("fork failed");
+		return EXIT_FAILURE;
+	}
+
+	if (pid == 0) {
+		/** child process **/
+		printf("   `- loop: initializing\n");
+
+		if (setsid() < 0 || signal(SIGUSR1, handle_signal) == SIG_ERR) {
+			_exit(EXIT_FAILURE);
+		}
+
+		close(STDIN_FILENO);
+		close(STDOUT_FILENO);
+		close(STDERR_FILENO);
+		close(pipe_fd[0]);
+
+		child_ret = SUCC_ECODE;
+		write(pipe_fd[1], &child_ret, sizeof(child_ret));
+		close(pipe_fd[1]);
+
+		while (!stop) {
+			sleep(1);
+		}
+
+		_exit(SUCC_ECODE);
+	}
+
+	/** parent process **/
+	close(pipe_fd[1]);
+
+	ret = -1;
+	if (read(pipe_fd[0], &ret, sizeof(ret)) != sizeof(ret) || ret != SUCC_ECODE) {
+		printf("Error starting loop\n");
+		goto cleanup;
+	}
+
+	read(pipe_fd[0], &ret, 1);
+	close(pipe_fd[0]);
+
+	printf("--- Loop process started (pid: %d) ---\n", pid);
+
+	printf("--- Checkpoint ---\n");
+	criu_init_opts();
+	criu_set_service_binary(argv[1]);
+	criu_set_images_dir_fd(img_fd);
+	criu_set_pid(pid);
+	criu_set_log_level(CRIU_LOG_DEBUG);
+
+	/* The RPC config file should overwrite the log-file set below */
+	printf("Setting dump RPC config file: %s\n", conf_file);
+	criu_set_config_file(conf_file);
+	criu_set_log_file("dump.log");
+
+	ret = criu_dump();
+	if (ret < 0) {
+		what_err_ret_mean(ret);
+		kill(pid, SIGKILL);
+		printf("criu dump failed\n");
+		goto cleanup;
+	}
+
+	printf("   `- Dump succeeded\n");
+	waitpid(pid, NULL, 0);
+
+	if (check_log_file()) {
+		printf("Error: log file not overwritten by RPC config file\n");
+		goto cleanup;
+	}
+
+	printf("--- Restore loop ---\n");
+	criu_init_opts();
+	criu_set_images_dir_fd(img_fd);
+	criu_set_log_level(CRIU_LOG_DEBUG);
+
+	/* The RPC config file should overwrite the log-file set below */
+	printf("Setting restore RPC config file: %s\n", conf_file);
+	criu_set_config_file(conf_file);
+	criu_set_log_file("restore.log");
+
+	pid = criu_restore_child();
+	if (pid <= 0) {
+		what_err_ret_mean(pid);
+		ret = EXIT_FAILURE;
+		goto cleanup;
+	}
+
+	printf("   `- Restore returned pid %d\n", pid);
+	kill(pid, SIGUSR1);
+
+	if (check_log_file()) {
+		printf("Error: log file not overwritten by RPC config file\n");
+		goto cleanup;
+	}
+
+cleanup:
+	if (waitpid(pid, &ret, 0) < 0) {
+		perror("waitpid failed");
+		return EXIT_FAILURE;
+	}
+
+	printf("Remove RPC config file: %s\n", conf_file);
+	unlink(conf_file);
+	return chk_exit(ret, SUCC_ECODE);
+}