setup /etc/hostname for container

Signed-off-by: Gao feng <omarapazanadi@gmail.com>

src/container.c

@@ -431,39 +431,48 @@ static int container_setup_sysctl(struct hyper_container *container)
 	return 0;
 }
 
-static int container_setup_dns(struct hyper_container *container)
+static int container_binding_file(char *src, char *dest)
 {
 	int fd;
 	struct stat st;
-	char *src = "/tmp/hyper/resolv.conf";
 
 	if (stat(src, &st) < 0) {
 		if (errno == ENOENT) {
 			fprintf(stdout, "no dns configured\n");
 			return 0;
 		}
 
-		perror("stat resolve.conf failed");
+		fprintf(stderr, "stat %s failed", src);
 		return -1;
 	}
 
-	hyper_mkdir("./etc", 0755);
-
-	fd = open("./etc/resolv.conf", O_CREAT| O_WRONLY, 0644);
+	fd = open(dest, O_CREAT| O_WRONLY, 0644);
 	if (fd < 0) {
-		perror("create /etc/resolv.conf failed");
+		fprintf(stderr, "create %s failed", dest);
 		return -1;
 	}
 	close(fd);
 
-	if (mount(src, "./etc/resolv.conf", NULL, MS_BIND, NULL) < 0) {
-		perror("bind to /etc/resolv.conf failed");
+	if (mount(src, dest, NULL, MS_BIND, NULL) < 0) {
+		fprintf(stderr, "bind to %s failed", dest);
 		return -1;
 	}
 
 	return 0;
 }
 
+static int container_setup_dns()
+{
+	hyper_mkdir("./etc", 0755);
+	return container_binding_file("/tmp/hyper/resolv.conf", "./etc/resolv.conf");
+}
+
+static int container_setup_hostname()
+{
+	hyper_mkdir("./etc", 0755);
+	return container_binding_file("/tmp/hyper/hostname", "./etc/hostname");
+}
+
 static int container_setup_workdir(struct hyper_container *container)
 {
 	if (container->initialize) {
@@ -637,11 +646,16 @@ static int hyper_setup_container_rootfs(void *data)
 		goto fail;
 	}
 
-	if (container_setup_dns(container) < 0) {
+	if (container_setup_dns() < 0) {
 		fprintf(stderr, "container sets up dns failed\n");
 		goto fail;
 	}
 
+	if (container_setup_hostname() < 0) {
+		fprintf(stderr, "container sets up hostname failed\n");
+		goto fail;
+	}
+
 	// manipulate the rootfs of the container/namespace: move the prepared path @rootfs to /
 	if (mount(rootfs, "/", NULL, MS_MOVE, NULL) < 0) {
 		perror("failed to move rootfs");

src/init.c

@@ -510,7 +510,12 @@ static int hyper_setup_pod(struct hyper_pod *pod)
 	}
 
 	if (hyper_setup_dns(pod) < 0) {
-		fprintf(stderr, "setup network failed\n");
+		fprintf(stderr, "setup dns file failed\n");
+		return -1;
+	}
+
+	if (hyper_setup_hostname(pod) < 0) {
+		fprintf(stderr, "setup hostname file failed\n");
 		return -1;
 	}
 

src/net.c

@@ -677,6 +677,40 @@ int hyper_cmd_setup_route(char *json, int length) {
 	return ret;
 }
 
+int hyper_setup_hostname(struct hyper_pod *pod)
+{
+	int l, fd, ret = -1, len = 0, size = 0;
+	char buf[512];
+
+	if (pod->hostname == NULL)
+		return 0;
+
+	fd = open("/tmp/hyper/hostname", O_CREAT| O_TRUNC| O_WRONLY, 0644);
+	if (fd < 0) {
+		perror("create /tmp/hostname failed");
+		return -1;
+	}
+
+	size = snprintf(buf, sizeof(buf), "%s\n", pod->hostname);
+	if (size < 0) {
+		fprintf(stderr, "sprintf hostname failed\n");
+		goto out;
+	}
+
+	while (len < size) {
+		l = write(fd, buf + len, size - len);
+		if (l < 0) {
+			perror("fail to write hostname");
+			goto out;
+		}
+		len += l;
+	}
+	ret = 0;
+out:
+	close(fd);
+	return ret;
+}
+
 int hyper_write_dns_file(int fd, char *field, char **data, int num)
 {
 	int i = 0, len = 0, ret = -1, size;

src/net.h

@@ -49,6 +49,7 @@ int hyper_setup_network(struct hyper_pod *pod);
 int hyper_cmd_setup_interface(char *json, int length);
 int hyper_cmd_setup_route(char *json, int length);
 int hyper_setup_dns(struct hyper_pod *pod);
+int hyper_setup_hostname(struct hyper_pod *pod);
 int hyper_get_type(int fd, uint32_t *type);
 int hyper_send_type(int fd, uint32_t type);
 int hyper_send_data_block(int fd, uint8_t *data, uint32_t len);