syscall test

common.h

#ifndef __COMMON_H
#define __COMMON_H

#define ERRNO_OFFSET	0x80

#endif

main.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <spawn.h>
#include <limits.h>
#include <signal.h>

#include "common.h"

#define REPORT(func, status)	\
	do {	\
		if (WIFEXITED((status)) &&	\
				WEXITSTATUS((status)) > ERRNO_OFFSET) {	\
			fprintf(stdout, "run '%s' failed during other syscall: %s\n",	\
					(func), strerror(WEXITSTATUS((status))-ERRNO_OFFSET));	\
		} else if (WIFEXITED((status)) &&	\
					WEXITSTATUS((status)) != EXIT_SUCCESS) {	\
			fprintf(stdout, "'%s' test failed: %s\n",	\
					(func), strerror(WEXITSTATUS((status))));	\
		} else if (WIFEXITED((status)) &&	\
					WEXITSTATUS((status)) == EXIT_SUCCESS) {	\
			fprintf(stdout, "'%s' test pass!\n", (func));	\
		} else {	\
			fprintf(stdout, "'%s' test terminated abnormally\n", func);	\
		}	\
	} while(0)

char **environ;

int main(int argc, char *argv[]) {
	int retval, status;
	pid_t prog;
	char path[PATH_MAX] = {0}, prefix[PATH_MAX] = {0};
	char *syscalls[] = {
		"write"
	};

	if (getcwd(prefix, sizeof(prefix)) == NULL) {
		fprintf(stderr, "getcwd failed: %s\n", strerror(errno));
		return 0;
	}

	for (int i = 0; i < sizeof(syscalls)/sizeof(char *); i++) {
		retval = snprintf(path, sizeof(path), "%s/%s", prefix, syscalls[i]);
		path[retval] = '\0';

		retval = posix_spawnp(&prog, path, NULL, NULL, argv, environ);
		if (retval != 0) {
			fprintf(stderr, "posix_spawnp('%s') failed: %s\n",
					path, strerror(errno));
		}

		while (waitpid(prog, &status, 0) != prog && errno == EINTR)
			continue;

		if (retval == 0)
			REPORT(syscalls[i], status);
	}

	return 0;
}

write.c

#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>

#include "common.h"

int main(int argc, char *argv[]) {
	int fd;
	char buffer[64] = "1234";

	fd = syscall(__NR_open, "/dev/null", O_WRONLY);
	if (fd < 0)
		return errno+ERRNO_OFFSET;

	syscall(__NR_write, fd, buffer, strlen(buffer));

	return errno;
}