Added a very minimalistic SMTP client to send mails via a local Exim

src/libfast/Makefile.am

@@ -1,7 +1,7 @@
 lib_LTLIBRARIES = libfast.la
 
 libfast_la_SOURCES = context.h dispatcher.c request.h session.h \
-  controller.h dispatcher.h request.c session.c filter.h
+  controller.h dispatcher.h request.c session.c filter.h smtp.c smtp.h
 libfast_la_LIBADD = $(top_builddir)/src/libstrongswan/libstrongswan.la \
   -lfcgi -lneo_cgi -lneo_cs -lneo_utl -lz $(PTHREADLIB)
 INCLUDES = -I$(top_srcdir)/src/libstrongswan -I/usr/include/ClearSilver

src/libfast/smtp.c

@@ -0,0 +1,184 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * This program 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 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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 General Public License
+ * for more details.
+ */
+
+#include "smtp.h"
+
+#include <unistd.h>
+#include <errno.h>
+
+#include <debug.h>
+
+typedef struct private_smtp_t private_smtp_t;
+
+/**
+ * Private data of an smtp_t object.
+ */
+struct private_smtp_t {
+
+	/**
+	 * Public smtp_t interface.
+	 */
+	smtp_t public;
+
+	/**
+	 * file stream to SMTP server
+	 */
+	FILE *f;
+};
+
+/**
+ * Read the response code from an SMTP server
+ */
+static int read_response(private_smtp_t *this)
+{
+	char buf[256], *end;
+	int res = 0;
+
+	while (TRUE)
+	{
+		if (!fgets(buf, sizeof(buf), this->f))
+		{
+			return 0;
+		}
+		res = strtol(buf, &end, 10);
+		switch (*end)
+		{
+			case '-':
+				continue;
+			case ' ':
+			case '\0':
+			case '\n':
+				break;
+			default:
+				return 0;
+		}
+		break;
+	}
+	return res;
+}
+
+/**
+ * write a SMTP command to the server, read response code
+ */
+static int write_cmd(private_smtp_t *this, char *fmt, ...)
+{
+	char buf[256];
+	va_list args;
+
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	if (fprintf(this->f, "%s\n", buf) < 1)
+	{
+		DBG1("sending SMTP command failed");
+		return 0;
+	}
+	return read_response(this);
+}
+
+METHOD(smtp_t, send_mail, bool,
+	private_smtp_t *this, char *from, char *to, char *subject, char *fmt, ...)
+{
+	va_list args;
+
+	if (write_cmd(this, "MAIL FROM:<%s>", from) != 250)
+	{
+		DBG1("SMTP MAIL FROM failed");
+		return FALSE;
+	}
+	if (write_cmd(this, "RCPT TO:<%s>", to) != 250)
+	{
+		DBG1("SMTP RCPT TO failed");
+		return FALSE;
+	}
+	if (write_cmd(this, "DATA") != 354)
+	{
+		DBG1("SMTP DATA failed");
+		return FALSE;
+	}
+
+	fprintf(this->f, "From: %s\n", from);
+	fprintf(this->f, "To: %s\n", to);
+	fprintf(this->f, "Subject: %s\n", subject);
+	fprintf(this->f, "\n");
+	va_start(args, fmt);
+	vfprintf(this->f, fmt, args);
+	va_end(args);
+	fprintf(this->f, "\n.\n");
+	return read_response(this) == 250;
+}
+
+
+METHOD(smtp_t, destroy, void,
+	private_smtp_t *this)
+{
+	write_cmd(this, "QUIT");
+	fclose(this->f);
+	free(this);
+}
+
+/**
+ * See header
+ */
+smtp_t *smtp_create()
+{
+	private_smtp_t *this;
+	struct sockaddr_in addr;
+	int s;
+
+	INIT(this,
+		.public = {
+			.send_mail = _send_mail,
+			.destroy = _destroy,
+		},
+	);
+
+	s = socket(AF_INET, SOCK_STREAM, 0);
+	if (s < 0)
+	{
+		DBG1("opening SMTP socket failed: %s", strerror(errno));
+		free(this);
+		return NULL;
+	}
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+	addr.sin_port = htons(25);
+	if (connect(s, (struct sockaddr*)&addr, sizeof(addr)) < 0)
+	{
+		DBG1("connecting to SMTP server failed: %s", strerror(errno));
+		close(s);
+		free(this);
+		return NULL;
+	}
+	this->f = fdopen(s, "a+");
+	if (!this->f)
+	{
+		DBG1("opening stream to SMTP server failed: %s", strerror(errno));
+		close(s);
+		free(this);
+		return NULL;
+	}
+	if (read_response(this) != 220 ||
+		write_cmd(this, "EHLO localhost") != 250)
+	{
+		DBG1("SMTP EHLO failed");
+		fclose(this->f);
+		free(this);
+		return NULL;
+	}
+	return &this->public;
+}
+

src/libfast/smtp.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * This program 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 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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 General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup smtp smtp
+ * @{ @ingroup libfast
+ */
+
+#ifndef SMTP_H_
+#define SMTP_H_
+
+typedef struct smtp_t smtp_t;
+
+#include <library.h>
+
+/**
+ * Ultra-minimalistic SMTP client. Works at most with Exim on localhost.
+ */
+struct smtp_t {
+
+	/**
+	 * Send an e-mail message.
+	 *
+	 * @param from		sender address
+	 * @param to		receipient address
+	 * @param subject	mail subject
+	 * @param fmt		mail body format string
+	 * @param ...		arguments for body format string
+	 */
+	bool (*send_mail)(smtp_t *this, char *from, char *to,
+					  char *subject, char *fmt, ...);
+
+	/**
+	 * Destroy a smtp_t.
+	 */
+	void (*destroy)(smtp_t *this);
+};
+
+/**
+ * Create a smtp instance.
+ */
+smtp_t *smtp_create();
+
+#endif /** SMTP_H_ @}*/