From 7cfede3e206592ad0e4cb7a3a63a1e18ee7a5bad Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom.smeding@gmail.com>
Date: Sun, 12 Jul 2020 12:12:54 +0200
Subject: ssh: Some executable renamings

---
 ssh/ssh_client.c | 153 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)
 create mode 100644 ssh/ssh_client.c

(limited to 'ssh/ssh_client.c')

diff --git a/ssh/ssh_client.c b/ssh/ssh_client.c
new file mode 100644
index 0000000..5c7f084
--- /dev/null
+++ b/ssh/ssh_client.c
@@ -0,0 +1,153 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <poll.h>
+#include <unistd.h>
+#include "util.h"
+#include "sshnc.h"
+
+
+static bool prompt_yn(const char *text) {
+	printf("%s", text);
+	fflush(stdout);
+
+	bool response;
+
+	char *line = NULL;
+	size_t linelen = 0;
+	while (true) {
+		ssize_t nr = getline(&line, &linelen, stdin);
+		if (nr == -1) {
+			perror("getline");
+			exit(1);
+		}
+
+		while (nr > 0 && isspace(line[nr - 1])) nr--;
+
+		for (ssize_t i = 0; i < nr; i++) line[i] = tolower(line[i]);
+
+		if ((nr == 1 && line[0] == 'y') || (nr == 3 && memcmp(line, "yes", 3) == 0)) {
+			response = true;
+			break;
+		}
+		if ((nr == 1 && line[0] == 'n') || (nr == 2 && memcmp(line, "no", 2) == 0)) {
+			response = false;
+			break;
+		}
+
+		printf("Please answer with 'y', 'n', 'yes' or 'no'. [y/n]");
+		fflush(stdout);
+	}
+
+	free(line);
+	return response;
+}
+
+static bool hostkey_checker(const unsigned char *hash, size_t length, void *userdata) {
+	(void)userdata;
+	printf("Server host key hash: %s\n", sshnc_print_hash(hash, length));
+
+	bool response = prompt_yn(
+			"Does this hash match the one given to you by the server administrator, or by a\n"
+			"member that you trust and is already connected to the server? [y/n] ");
+	if (!response) {
+		printf("Disconnecting.\n");
+	}
+
+	return response;
+}
+
+int main(int argc, char **argv) {
+	const char *server_host = NULL;
+	int port = 2222;
+
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s <server[:port]>\n", argv[0]);
+		fprintf(stderr, "If port is not specified, %d is assumed.\n", port);
+		return 1;
+	}
+
+	if (!parse_host_port(argv[1], &server_host, &port)) {
+		fprintf(stderr, "Cannot parse host:port from argument '%s'\n", argv[1]);
+		return 1;
+	}
+
+	struct sshnc_client *client;
+	enum sshnc_retval ret = sshnc_connect(
+			server_host, port, "tomsg", "tomsg", hostkey_checker, NULL, &client);
+
+	if (ret != SSHNC_OK) {
+		fprintf(stderr, "Could not connect: %s\n", sshnc_strerror(ret));
+		return 1;
+	}
+
+	struct pollfd polls[2];
+	polls[0] = (struct pollfd){
+		.fd = sshnc_poll_fd(client),
+		.events = POLLIN,
+	};
+	polls[1] = (struct pollfd){
+		.fd = STDIN_FILENO,
+		.events = POLLIN,
+	};
+
+	while (true) {
+		int pollret = poll(polls, sizeof polls / sizeof polls[0], -1);
+		if (pollret < 0) {
+			perror("poll");
+			goto cleanup;
+		}
+
+		if (polls[0].revents & (POLLERR | POLLNVAL)) {
+			fprintf(stderr, "Error reading from SSH socket\n");
+			goto cleanup;
+		}
+		if (polls[1].revents & (POLLERR | POLLNVAL)) {
+			fprintf(stderr, "Error reading from stdin\n");
+			goto cleanup;
+		}
+
+		if (polls[0].revents & (POLLIN | POLLHUP)) {
+			char buffer[4096];
+			size_t length = 0;
+			ret = sshnc_maybe_recv(client, sizeof buffer, buffer, &length);
+			if (ret == SSHNC_OK) {
+				fwrite(buffer, 1, length, stdout);
+			} else if (ret == SSHNC_EOF) {
+				break;
+			} else if (ret != SSHNC_AGAIN) {
+				fprintf(stderr, "Error on SSH recv: %s\n", sshnc_strerror(ret));
+				goto cleanup;
+			}
+		}
+
+		if (polls[1].revents & (POLLIN | POLLHUP)) {
+			char buffer[4096];
+			ssize_t nr = read(STDIN_FILENO, buffer, sizeof buffer);
+			if (nr < 0) {
+				perror("Error reading from stdin");
+				goto cleanup;
+			}
+			if (nr == 0) {
+				break;
+			}
+
+			ret = sshnc_send(client, buffer, nr);
+			if (ret == SSHNC_EOF) {
+				break;
+			} else if (ret != SSHNC_OK) {
+				fprintf(stderr, "Error on SSH send: %s\n", sshnc_strerror(ret));
+				goto cleanup;
+			}
+		}
+	}
+
+	sshnc_close(client);
+	return 0;
+
+cleanup:
+	sshnc_close(client);
+	return 1;
+}
-- 
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