add test for link, unlink, rename

test/Makefile

@@ -4,7 +4,7 @@ PROJECT_DIR := $(realpath $(CUR_DIR)/../)
 # Dependencies: need to be compiled but not to run by any Makefile target
 TEST_DEPS := dev_null
 # Tests: need to be compiled and run by test-% target
-TESTS := empty argv hello_world malloc file getpid spawn pipe time truncate readdir mkdir
+TESTS := empty argv hello_world malloc file getpid spawn pipe time truncate readdir mkdir link
 # Benchmarks: need to be compiled and run by bench-% target
 BENCHES := spawn_and_exit_latency pipe_throughput
 

test/link/Makefile

@@ -0,0 +1,5 @@
+include ../test_common.mk
+
+EXTRA_C_FLAGS :=
+EXTRA_LINK_FLAGS :=
+BIN_ARGS :=

test/link/main.c

@@ -0,0 +1,91 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+int main(int argc, const char* argv[]) {
+	const char* file_name = "tmp.txt";
+	const char* link_name = "link.txt";
+	const char* write_msg = "Hello World\n";
+	char read_buf[128] = {0};
+	int ret;
+
+	// create a file and write message
+	int flags = O_WRONLY | O_CREAT| O_TRUNC;
+	int mode = 00666;
+	int fd = open(file_name, flags, mode);
+	if (fd < 0) {
+		printf("ERROR: failed to open a file for write\n");
+		return -1;
+	}
+	int len = write(fd, write_msg, strlen(write_msg));
+	if (len <= 0) {
+		printf("ERROR: failed to write to the file\n");
+		return -1;
+	}
+	close(fd);
+
+	// link
+	ret = link(file_name, link_name);
+	if(ret < 0) {
+		printf("ERROR: failed to link the file\n");
+		return -1;
+	}
+
+	// read the link file
+	fd = open(link_name, O_RDONLY, 00666);
+	if (fd < 0) {
+		printf("ERROR: failed to open the file for read\n");
+		return -1;
+	}
+	len = read(fd, read_buf, sizeof(read_buf));
+	if (len != strlen(write_msg)) {
+		printf("ERROR: failed to read to the file\n");
+		return -1;
+	}
+	ret = strcmp(write_msg, read_buf);
+	if (ret != 0) {
+		printf("ERROR: the message read from the file is not as it was written\n");
+		return -1;
+	}
+
+	// unlink
+	ret = unlink(link_name);
+	if(ret < 0) {
+		printf("ERROR: failed to link the file\n");
+		return -1;
+	}
+
+	// stat
+	struct stat stat_buf;
+	ret = stat(link_name, &stat_buf);
+	if(!(ret < 0 && errno == ENOENT)) {
+		printf("ERROR: stat on \"%s\" should return ENOENT", link_name);
+		return -1;
+	}
+
+	// rename
+	ret = rename(file_name, link_name);
+	if(ret < 0) {
+		printf("ERROR: failed to rename the file");
+		return -1;
+	}
+
+	// stat
+	ret = stat(file_name, &stat_buf);
+	if(!(ret < 0 && errno == ENOENT)) {
+		printf("ERROR: stat on \"%s\" should return ENOENT", file_name);
+		return -1;
+	}
+	ret = stat(link_name, &stat_buf);
+	if(ret < 0) {
+		printf("ERROR: failed to stat the file");
+		return -1;
+	}
+
+    printf("link, unlink, rename test successful\n");
+    return 0;
+}