wip: echo example

examples/echo/echo.c

@@ -0,0 +1,79 @@
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define BUF_SIZE 1024
+
+int connection_listener(int, int);
+int request_handler(int);
+
+int main(int argc, char **argv) {
+  if (argc < 2) {
+    fprintf(stderr, "usage: %s SUBCOMMAND...\n", argv[0]);
+    return -1;
+  }
+
+  if (strcmp(argv[1], "connection_listener") == 0) {
+    if (argc != 4) {
+      fprintf(stderr, "usage: %s connection_listener SERVER_FD WRITE_PIPE_FD\n",
+              argv[0]);
+      return -1;
+    }
+
+    return connection_listener(atoi(argv[2]), atoi(argv[3]));
+  } else if (strcmp(argv[1], "request_handler") == 0) {
+    if (argc != 3) {
+      fprintf(stderr, "usage: %s request_handler CLIENT_FD\n", argv[0]);
+      return -1;
+    }
+
+    return request_handler(atoi(argv[2]));
+  }
+
+  fprintf(stderr, "unrecognised subcommand\n");
+  return -1;
+}
+
+int connection_listener(int server_fd, int write_pipe) {
+  while (1) {
+    struct sockaddr_in client;
+    socklen_t client_len = sizeof(client);
+
+    int client_fd = accept(server_fd, (struct sockaddr *)&client, &client_len);
+    if (client_fd < 0) {
+      perror("accept");
+    }
+
+    write(write_pipe, &client_fd, sizeof(client_fd));
+    fprintf(stderr, "sent client_fd: %d\n", client_fd);
+  }
+
+  return 0;
+}
+
+int request_handler(int client_fd) {
+  char buf[BUF_SIZE];
+  while (1) {
+    int read = recv(client_fd, buf, BUF_SIZE, 0);
+    if (read < 0) {
+      perror("recv");
+      return read;
+    }
+
+    if (!read) {
+      fprintf(stderr, "connection terminated\n");
+      return 0;
+    }
+
+    if (send(client_fd, buf, read, 0) < 0) {
+      perror("send");
+      return -1;
+    }
+  }
+
+  return 0;
+}

examples/echo/spec.json

@@ -0,0 +1,30 @@
+{
+    "entrypoints": {
+        "connection_listener": {
+            "args": [
+                "BinaryName",
+                "Entrypoint",
+                {
+                    "TcpListener": {
+                        "port": 8080
+                    }
+                },
+                {
+                    "Pipe": {
+                        "Tx": "clients"
+                    }
+                }
+            ]
+        },
+        "request_handler": {
+            "trigger": {
+                "Pipe": "clients"
+            },
+            "args": [
+                "BinaryName",
+                "Entrypoint",
+                "PipeTrigger"
+            ]
+        }
+    }
+}