Added an API for Tox DNS lookup.

src/twc-dns.c

@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2014 Håvard Pettersson <haavard.pettersson@gmail.com>
+ *
+ * This file is part of Tox-WeeChat.
+ *
+ * Tox-WeeChat is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Tox-WeeChat 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Tox-WeeChat.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <weechat/weechat-plugin.h>
+#include <tox/tox.h>
+
+#include "twc.h"
+#include "twc-utils.h"
+
+#include "twc-dns.h"
+
+/**
+ * Struct for holding information about a Tox DNS query callback.
+ */
+struct t_twc_dns_callback_info
+{
+    void (*callback)(void *data,
+                     enum t_twc_dns_rc rc,
+                     const uint8_t *tox_id);
+    void *data;
+
+    struct t_hook *hook;
+};
+
+/**
+ * Callback when the DNS resolver child process has written to our file
+ * descriptor. Process the data a bit and pass it on to the original callback.
+ */
+int
+twc_dns_fd_callback(void *data, int fd)
+{
+    struct t_twc_dns_callback_info *callback_info = data;
+
+    char buffer[TOX_FRIEND_ADDRESS_SIZE * 2 + 1];
+    ssize_t size = read(fd, buffer, sizeof(buffer) - 1);
+    buffer[size] = '\0';
+
+    if (size > 0)
+    {
+        if (size == TOX_FRIEND_ADDRESS_SIZE * 2)
+        {
+            callback_info->callback(callback_info->data,
+                                    TWC_DNS_RC_OK, (uint8_t *)buffer);
+        }
+        else
+        {
+            int rc = atoi(buffer);
+            callback_info->callback(callback_info->data,
+                                    rc, NULL);
+        }
+
+        weechat_unhook(callback_info->hook);
+        free(callback_info);
+    }
+
+    return WEECHAT_RC_OK;
+}
+
+/**
+ * Perform a Tox DNS lookup and write either a Tox ID (as a hexadecimal string)
+ * or an error code (as a decimal string) to out_fd.
+ */
+void
+twc_perform_dns_lookup(const char *dns_id, int out_fd)
+{
+    dprintf(out_fd, "%d", TWC_DNS_RC_ERROR);
+}
+
+/**
+ * Perform a Tox DNS lookup. If return code (rc) parameter in callback is
+ * TWC_DNS_RC_OK, tox_id contains the resolved Tox ID. For any other value,
+ * something caused the Tox ID not to be found.
+ *
+ * If twc_dns_query returns TWC_DNS_RC_ERROR, the callback will never be
+ * called.
+ */
+enum t_twc_dns_rc
+twc_dns_query(const char *dns_id,
+              void (*callback)(void *data,
+                               enum t_twc_dns_rc rc,
+                               const uint8_t *tox_id),
+              void *callback_data)
+{
+    if (!callback) return TWC_DNS_RC_OK;
+
+    int fifo[2];
+    if (pipe(fifo) < 0)
+        return TWC_DNS_RC_ERROR;
+
+    pid_t pid;
+    if ((pid = fork()) == -1)
+    {
+        return TWC_DNS_RC_ERROR;
+    }
+    else if (pid == 0)
+    {
+        twc_perform_dns_lookup(dns_id, fifo[1]);
+        _exit(0);
+    }
+    else
+    {
+        struct t_twc_dns_callback_info *callback_info
+            = malloc(sizeof(struct t_twc_dns_callback_info));
+        if (!callback_info)
+            return TWC_DNS_RC_ERROR;
+
+        callback_info->callback = callback;
+        callback_info->data = callback_data;
+        callback_info->hook = weechat_hook_fd(fifo[0], 1, 0, 0,
+                                              twc_dns_fd_callback,
+                                              callback_info);
+    }
+
+    return TWC_DNS_RC_OK;
+}
+

src/twc-dns.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2014 Håvard Pettersson <haavard.pettersson@gmail.com>
+ *
+ * This file is part of Tox-WeeChat.
+ *
+ * Tox-WeeChat is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Tox-WeeChat 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Tox-WeeChat.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TOX_WEECHAT_DNS_H
+#define TOX_WEECHAT_DNS_H
+
+#include <stdint.h>
+
+enum t_twc_dns_rc
+{
+    TWC_DNS_RC_OK = 0,
+    TWC_DNS_RC_ERROR = -1,
+};
+
+enum t_twc_dns_rc
+twc_dns_query(const char *dns_id,
+              void (*callback)(void *data,
+                               enum t_twc_dns_rc rc,
+                               const uint8_t *tox_id),
+              void *callback_data);
+
+#endif // TOX_WEECHAT_DNS_H
+