1 files changed, 120 insertions, 0 deletions
diff --git a/src/ipc.c b/src/ipc.c
new file mode 100644
index 0000000..2e92097
--- /dev/null
+++ b/src/ipc.c
@@ -0,0 +1,120 @@
+#include <json-c/json_object.h>
+#include <json-c/json_tokener.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include "ipc.h"
+#include "log.h"
+
+static int ipc_open(void);
+static int ipc_send(int socket, struct json_object *request);
+static struct json_object *ipc_receive(int socket);
+
+struct json_object *ipc_submit(struct json_object *request)
+{
+	int sock = ipc_open();
+	if (sock == -1) {
+		return NULL;
+	}
+
+	if (ipc_send(sock, request) == -1) {
+		close(sock);
+		return NULL;
+	}
+
+	struct json_object *resp = ipc_receive(sock);
+	close(sock);
+	return resp;
+}
+
+/*
+ * Open a connection to the UNIX socket specified by
+ * the environment variable GREETD_SOCK.
+ *
+ * Returns the socket file descriptor on success, or -1 on failure.
+ */
+int ipc_open(void)
+{
+	char *greetd_sock = getenv("GREETD_SOCK");
+
+	if (greetd_sock == NULL) {
+		log_error("GREETD_SOCK not set.\n");
+		return -1;
+	}
+
+	int sock = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (sock == -1) {
+		log_error("Unable to create socket: %s\n", strerror(errno));
+		return -1;
+	}
+
+	struct sockaddr_un remote = { .sun_family = AF_UNIX };
+	strncpy(remote.sun_path, greetd_sock, sizeof(remote.sun_path));
+
+	if (connect(sock, (struct sockaddr *)&remote, sizeof(remote)) == -1) {
+		log_error("Unable to connect to greetd: %s\n", strerror(errno));
+		close(sock);
+		return -1;
+	}
+	return sock;
+}
+
+/*
+ * Send an IPC request to the specified socket.
+ *
+ * Returns 0 on success, or -1 on failure.
+ */
+int ipc_send(int sock, struct json_object *request)
+{
+	const char *str = json_object_to_json_string(request);
+	uint32_t len = strlen(str);
+
+	if (send(sock, &len, sizeof(len), 0) == -1) {
+		log_error("Error sending request size: %s\n", strerror(errno));
+		return -1;
+	}
+
+	if (send(sock, str, len, 0) == -1) {
+		log_error("Error sending request: %s\n", strerror(errno));
+		return -1;
+	}
+	return 0;
+}
+
+/*
+ * Receive an IPC response on the specified socket.
+ *
+ * Returns the response on success, or NULL on failure.
+ */
+struct json_object *ipc_receive(int sock)
+{
+	uint32_t len = 0;
+
+	if (recv(sock, &len, sizeof(len), 0) != sizeof(len)) {
+		log_error("Error receiving response size: %s\n", strerror(errno));
+		return NULL;
+	}
+
+	char *buf = malloc(len + 1);
+	if (recv(sock, buf, len, 0) != len) {
+		log_error("Error receiving response: %s\n", strerror(errno));
+		free(buf);
+		return NULL;
+	}
+
+	buf[len] = '\0';
+
+	enum json_tokener_error error;
+	struct json_object *resp = json_tokener_parse_verbose(buf, &error);
+	free(buf);
+
+	if (resp == NULL) {
+		log_error("Error parsing response: %s\n", json_tokener_error_desc(error));
+	}
+	return resp;
+
+}