add some code

A basic client-server app, the client sends commands as an array of
strings. Hopefully I didn't mess up, and hopefully it'll be useful.

1 files changed, 160 insertions, 0 deletions

diff --git a/src/cmd.c b/src/cmd.c
new file mode 100644
index 0000000..c3ddf6c
--- /dev/null
+++ b/src/cmd.c
@@ -0,0 +1,160 @@
+#include "cmd.h"
+#include "log.h"
+#include "net.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+static size_t calc_buf_len(int argc, char **argv)
+{
+	size_t len = 0;
+	for (int i = 0; i < argc; ++i)
+		len += strlen(argv[i]) + 1;
+	return len;
+}
+
+static int calc_arr_len(const void *buf, size_t len)
+{
+	int argc = 0;
+	for (const char *it = buf; it < (const char *)buf + len; it += strlen(it) + 1)
+		++argc;
+	return argc;
+}
+
+static void arr_pack(char *dest, int argc, char **argv)
+{
+	for (int i = 0; i < argc; ++i) {
+		strcpy(dest, argv[i]);
+		dest += strlen(argv[i]) + 1;
+	}
+}
+
+static int arr_unpack(char **argv, int argc, const char *src)
+{
+	for (int i = 0; i < argc; ++i)
+		argv[i] = NULL;
+
+	for (int i = 0; i < argc; ++i) {
+		size_t len = strlen(src);
+
+		argv[i] = malloc(len);
+		if (!argv[i]) {
+			print_errno("malloc");
+			goto free;
+		}
+
+		strcpy(argv[i], src);
+		src += len + 1;
+	}
+
+	return 0;
+
+free:
+	for (int i = 0; i < argc; ++i)
+		if (argv[i])
+			free(argv[i]);
+		else
+			break;
+
+	return -1;
+}
+
+int cmd_send(int fd, const struct cmd *cmd)
+{
+	int ret = 0;
+
+	size_t len = calc_buf_len(cmd->argc, cmd->argv);
+	char *buf = malloc(len);
+	if (!buf) {
+		print_errno("malloc");
+		return -1;
+	}
+	arr_pack(buf, cmd->argc, cmd->argv);
+
+	ret = send_buf(fd, buf, len);
+	if (ret < 0)
+		goto free_buf;
+
+free_buf:
+	free(buf);
+
+	return ret;
+}
+
+int cmd_send_and_wait_for_result(int fd, const struct cmd *cmd, int *result)
+{
+	int ret = 0;
+
+	ret = cmd_send(fd, cmd);
+	if (ret < 0)
+		return ret;
+
+	ret = recv_static(fd, result, sizeof(*result));
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
+int cmd_recv(int fd, struct cmd *cmd)
+{
+	void *buf;
+	size_t len;
+	int ret = 0;
+
+	ret = recv_buf(fd, &buf, &len);
+	if (ret < 0)
+		return ret;
+
+	cmd->argc = calc_arr_len(buf, len);
+	cmd->argv = malloc(cmd->argc * sizeof(char *));
+	if (!cmd->argv) {
+		print_errno("malloc");
+		ret = -1;
+		goto free_buf;
+	}
+	memset(cmd->argv, 0, cmd->argc * sizeof(char *));
+
+	ret = arr_unpack(cmd->argv, cmd->argc, buf);
+	if (ret < 0)
+		goto free_argv;
+
+	goto free_buf;
+
+free_argv:
+	free(cmd->argv);
+
+free_buf:
+	free(buf);
+
+	return ret;
+}
+
+int cmd_recv_and_send_result(int fd, cmd_handler handler, void *arg)
+{
+	struct cmd cmd;
+	int result;
+	int ret = 0;
+
+	ret = cmd_recv(fd, &cmd);
+	if (ret < 0)
+		return ret;
+
+	result = handler(&cmd, arg);
+
+	ret = send_buf(fd, &result, sizeof(result));
+	if (ret < 0)
+		goto free_cmd;
+
+free_cmd:
+	cmd_free(&cmd);
+
+	return ret;
+}
+
+void cmd_free(const struct cmd *cmd)
+{
+	for (int i = 0; i < cmd->argc; ++i)
+		free(cmd->argv[i]);
+	free(cmd->argv);
+}