Add initial version of i3-input, an interactive tool for sending IPC commands

i3-input/ipc.c

@@ -0,0 +1,68 @@
+/*
+ * vim:ts=8:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ *
+ * © 2009 Michael Stapelberg and contributors
+ *
+ * See file LICENSE for license information.
+ *
+ */
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <err.h>
+
+/*
+ * Formats a message (payload) of the given size and type and sends it to i3 via
+ * the given socket file descriptor.
+ *
+ */
+void ipc_send_message(int sockfd, uint32_t message_size,
+                      uint32_t message_type, uint8_t *payload) {
+        int buffer_size = strlen("i3-ipc") + sizeof(uint32_t) + sizeof(uint32_t) + message_size;
+        char msg[buffer_size];
+        char *walk = msg;
+
+        strcpy(walk, "i3-ipc");
+        walk += strlen("i3-ipc");
+        memcpy(walk, &message_size, sizeof(uint32_t));
+        walk += sizeof(uint32_t);
+        memcpy(walk, &message_type, sizeof(uint32_t));
+        walk += sizeof(uint32_t);
+        memcpy(walk, payload, message_size);
+
+        int sent_bytes = 0;
+        int bytes_to_go = buffer_size;
+        while (sent_bytes < bytes_to_go) {
+                int n = write(sockfd, msg + sent_bytes, bytes_to_go);
+                if (n == -1)
+                        err(EXIT_FAILURE, "write() failed");
+
+                sent_bytes += n;
+                bytes_to_go -= n;
+        }
+}
+
+/*
+ * Connects to the i3 IPC socket and returns the file descriptor for the
+ * socket. die()s if anything goes wrong.
+ *
+ */
+int connect_ipc(char *socket_path) {
+	int sockfd = socket(AF_LOCAL, SOCK_STREAM, 0);
+        if (sockfd == -1)
+                err(EXIT_FAILURE, "Could not create socket");
+
+        struct sockaddr_un addr;
+        memset(&addr, 0, sizeof(struct sockaddr_un));
+        addr.sun_family = AF_LOCAL;
+        strcpy(addr.sun_path, socket_path);
+        if (connect(sockfd, (const struct sockaddr*)&addr, sizeof(struct sockaddr_un)) < 0)
+                err(EXIT_FAILURE, "Could not connect to i3");
+
+	return sockfd;
+}