--- /dev/null
+/* smtp-dummy - Dummy SMTP server that delivers mail to the given file
+ *
+ * Copyright © 2010 Carl Worth
+ *
+ * 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 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see http://www.gnu.org/licenses/ .
+ *
+ * Authors: Carl Worth <cworth@cworth.org>
+ */
+
+/* This (non-compliant) SMTP server listens on localhost, port 25025
+ * and delivers a mail received to the given filename, (specified as a
+ * command-line argument). It exists after the first client connection
+ * completes.
+ *
+ * It implements very little of the SMTP protocol, even less than
+ * specified as the minimum implementation in the SMTP RFC, (not
+ * implementing RSET, NOOP, nor VRFY). And it doesn't do any
+ * error-checking on the input.
+ *
+ * That is to say, if you use this program, you will very likely find
+ * cases where it doesn't do everything your SMTP client expects. You
+ * have been warned.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <netinet/ip.h>
+#include <netdb.h>
+#include <unistd.h>
+
+#define STRNCMP_LITERAL(var, literal) \
+ strncmp ((var), (literal), sizeof (literal) - 1)
+
+static void
+receive_data_to_file (FILE *peer, FILE *output)
+{
+ char *line = NULL;
+ size_t line_size;
+ ssize_t line_len;
+
+ while ((line_len = getline (&line, &line_size, peer)) != -1) {
+ if (STRNCMP_LITERAL (line, ".\r\n") == 0)
+ break;
+ if (line_len < 2)
+ continue;
+ if (line[line_len-1] == '\n' && line[line_len-2] == '\r') {
+ line[line_len-2] = '\n';
+ line[line_len-1] = '\0';
+ }
+ fprintf (output, "%s",
+ line[0] == '.' ? line + 1 : line);
+ }
+
+ free (line);
+}
+
+static int
+process_command (FILE *peer, FILE *output, const char *command)
+{
+ if (STRNCMP_LITERAL (command, "EHLO ") == 0) {
+ fprintf (peer, "502\r\n");
+ fflush (peer);
+ } else if (STRNCMP_LITERAL (command, "HELO ") == 0) {
+ fprintf (peer, "250 localhost\r\n");
+ fflush (peer);
+ } else if (STRNCMP_LITERAL (command, "MAIL FROM:") == 0 ||
+ STRNCMP_LITERAL (command, "RCPT TO:") == 0) {
+ fprintf (peer, "250 OK\r\n");
+ fflush (peer);
+ } else if (STRNCMP_LITERAL (command, "DATA") == 0) {
+ fprintf (peer, "354 End data with <CR><LF>.<CR><LF>\r\n");
+ fflush (peer);
+ receive_data_to_file (peer, output);
+ fprintf (peer, "250 OK\r\n");
+ fflush (peer);
+ } else if (STRNCMP_LITERAL (command, "QUIT") == 0) {
+ fprintf (peer, "221 BYE\r\n");
+ fflush (peer);
+ return 1;
+ } else {
+ fprintf (stderr, "Unknown command: %s\n", command);
+ }
+ return 0;
+}
+
+static void
+do_smtp_to_file (FILE *peer, FILE *output)
+{
+ char buf[4096];
+ ssize_t bytes;
+ char greeting[] = "220 localhost smtp-dummy\r\n";
+ char *line = NULL;
+ size_t line_size;
+ ssize_t line_len;
+
+ fprintf (peer, "220 localhost smtp-dummy\r\n");
+ fflush (peer);
+
+ while ((line_len = getline (&line, &line_size, peer)) != -1) {
+ if (process_command (peer, output, line))
+ break;
+ }
+
+ free (line);
+}
+
+int
+main (int argc, char *argv[])
+{
+ char *output_filename;
+ FILE *peer_file, *output;
+ int sock, peer, err;
+ struct sockaddr_in addr, peer_addr;
+ struct hostent *hostinfo;
+ socklen_t peer_addr_len;
+ int reuse;
+
+ if (argc != 2) {
+ fprintf (stderr, "Usage: %s <output-file>\n", argv[0]);
+ exit (1);
+ }
+
+ output_filename = argv[1];
+ output = fopen (output_filename, "w");
+ if (output == NULL) {
+ fprintf (stderr, "Failed to open %s for writing: %s\n",
+ output_filename, strerror (errno));
+ exit (1);
+ }
+
+ sock = socket (AF_INET, SOCK_STREAM, 0);
+ if (sock == -1) {
+ fprintf (stderr, "Error: socket() failed: %s\n",
+ strerror (errno));
+ exit (1);
+ }
+
+ reuse = 1;
+ err = setsockopt (sock, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof (reuse));
+ if (err) {
+ fprintf (stderr, "Error: setsockopt() failed: %s\n",
+ strerror (errno));
+ exit (1);
+ }
+
+ hostinfo = gethostbyname ("localhost");
+ if (hostinfo == NULL) {
+ fprintf (stderr, "Unknown host: localhost\n");
+ exit (1);
+ }
+
+ addr.sin_family = AF_INET;
+ addr.sin_port = htons (25025);
+ addr.sin_addr = *(struct in_addr *) hostinfo->h_addr;
+ err = bind (sock, (struct sockaddr *) &addr, sizeof(addr));
+ if (err) {
+ fprintf (stderr, "Error: bind() failed: %s\n",
+ strerror (errno));
+ close (sock);
+ exit (1);
+ }
+
+ err = listen (sock, 1);
+ if (err) {
+ fprintf (stderr, "Error: listen() failed: %s\n",
+ strerror (errno));
+ close (sock);
+ exit (1);
+ }
+
+ peer_addr_len = sizeof (peer_addr);
+ peer = accept (sock, (struct sockaddr *) &peer_addr, &peer_addr_len);
+ if (peer == -1) {
+ fprintf (stderr, "Error: accept() failed: %s\n",
+ strerror (errno));
+ exit (1);
+ }
+
+ peer_file = fdopen (peer, "w+");
+ if (peer_file == NULL) {
+ fprintf (stderr, "Error: fdopen() failed: %s\n",
+ strerror (errno));
+ return;
+ }
+
+ do_smtp_to_file (peer_file, output);
+
+ fclose (output);
+ fclose (peer_file);
+ close (sock);
+
+ return 0;
+}
projects / notmuch / blobdiff