Add pingbot

I literally just wrote this for a joke and will remove it in the next
commit. It's a bot that tries to ping timeout when it gets mentioned.

1 files changed, 176 insertions, 0 deletions

diff --git a/bin/pingbot.c b/bin/pingbot.c
new file mode 100644
index 00000000..5d600f6a
--- /dev/null
+++ b/bin/pingbot.c
@@ -0,0 +1,176 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/event.h>
+#include <sys/socket.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+typedef unsigned uint;
+
+__attribute__((format(printf, 2, 3)))
+static int pdprintf(int fd, const char *format, ...) {
+	va_list ap;
+	va_start(ap, format);
+	vprintf(format, ap);
+	va_end(ap);
+	va_start(ap, format);
+	int len = vdprintf(fd, format, ap);
+	va_end(ap);
+	return len;
+}
+
+int main(int argc, char *argv[]) {
+	int error;
+
+	const char *host = NULL;
+	const char *port = "6667";
+	const char *nick = "pingbot";
+	const char *join = NULL;
+	uint timeout = 120;
+	uint delay = 30;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "d:j:n:p:t:"))) {
+		switch (opt) {
+			break; case 'd': delay = strtoul(optarg, NULL, 0);
+			break; case 'j': join = optarg;
+			break; case 'n': nick = optarg;
+			break; case 'p': port = optarg;
+			break; case 't': timeout = strtoul(optarg, NULL, 0);
+			break; default:  return EX_USAGE;
+		}
+	}
+	if (optind < argc) host = argv[optind];
+	if (!host || !timeout) return EX_USAGE;
+
+	struct addrinfo *head;
+	struct addrinfo hints = {
+		.ai_family = AF_UNSPEC,
+		.ai_socktype = SOCK_STREAM,
+		.ai_protocol = IPPROTO_TCP,
+	};
+	error = getaddrinfo(host, port, &hints, &head);
+	if (error) errx(EX_NOHOST, "getaddrinfo: %s", gai_strerror(error));
+
+	int client = -1;
+	struct addrinfo *ai;
+	for (ai = head; ai; ai = ai->ai_next) {
+		client = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+		if (client < 0) err(EX_OSERR, "socket");
+
+		error = connect(client, ai->ai_addr, ai->ai_addrlen);
+		if (!error) break;
+
+		close(client);
+		client = -1;
+	}
+	if (client < 0) err(EX_UNAVAILABLE, "connect");
+
+	error = pdprintf(client, "NICK %1$s\r\nUSER %1$s 0 * :%1$s\r\n", nick);
+	if (error < 0) err(EX_IOERR, "pdprintf");
+
+	int kq = kqueue();
+	if (kq < 0) err(EX_OSERR, "kqueue");
+
+	struct kevent event;
+	EV_SET(&event, client, EVFILT_READ, EV_ADD, 0, 0, 0);
+	int nevents = kevent(kq, &event, 1, NULL, 0, NULL);
+	if (nevents < 0) err(EX_OSERR, "kevent");
+
+	char buf[4096];
+	size_t len = 0;
+	bool pong = true;
+	for (;;) {
+		nevents = kevent(kq, NULL, 0, &event, 1, NULL);
+		if (nevents < 0) err(EX_IOERR, "kevent");
+
+		if (event.filter == EVFILT_TIMER) {
+			char *ping = event.udata;
+			if (pong) {
+				error = pdprintf(client, "PONG %s\r\n", ping);
+				if (error < 0) err(EX_IOERR, "pdprintf");
+			}
+			pong = true;
+			free(ping);
+			continue;
+		}
+
+		ssize_t rlen = read(client, &buf[len], sizeof(buf) - len);
+		if (rlen < 0) err(EX_IOERR, "read");
+		len += (size_t)rlen;
+
+		char *crlf;
+		char *line = buf;
+		while (NULL != (crlf = strnstr(line, "\r\n", &buf[len] - line))) {
+			crlf[0] = '\0';
+			printf("%s\n", line);
+
+			if (line[0] == ':') strsep(&line, " ");
+			if (!line) errx(EX_PROTOCOL, "unexpected eol");
+			char *cmd = strsep(&line, " ");
+
+			if (!strcmp(cmd, "001") && join) {
+				error = pdprintf(client, "JOIN :%s\r\n", join);
+				if (error < 0) err(EX_IOERR, "pdprintf");
+
+			} else if (!strcmp(cmd, "PING")) {
+				EV_SET(
+					&event, 0, EVFILT_TIMER, EV_ADD | EV_ONESHOT,
+					NOTE_SECONDS, timeout - 1, strdup(line)
+				);
+				nevents = kevent(kq, &event, 1, NULL, 0, NULL);
+				if (nevents < 0) err(EX_OSERR, "kevent");
+
+			} else if (!strcmp(cmd, "PRIVMSG") && strcasestr(line, nick)) {
+				pong = false;
+
+			} else if (!strcmp(cmd, "ERROR")) {
+				close(client);
+				sleep(delay);
+
+				client = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+				if (client < 0) err(EX_OSERR, "socket");
+
+				error = connect(client, ai->ai_addr, ai->ai_addrlen);
+				if (error) err(EX_UNAVAILABLE, "connect");
+
+				error = pdprintf(
+					client, "NICK %1$s\r\nUSER %1$s 0 * :%1$s\r\n", nick
+				);
+				if (error < 0) err(EX_IOERR, "pdprintf");
+
+				EV_SET(&event, client, EVFILT_READ, EV_ADD, 0, 0, 0);
+				int nevents = kevent(kq, &event, 1, NULL, 0, NULL);
+				if (nevents < 0) err(EX_OSERR, "kevent");
+			}
+
+			line = &crlf[2];
+		}
+
+		len -= line - buf;
+		memmove(buf, line, len);
+	}
+}