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/* fakesmtp - A fake SMTP server used by the nmh test suite
*
* This code is Copyright (c) 2012, by the authors of nmh. See the
* COPYRIGHT file in the root directory of the nmh distribution for
* complete copyright information.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "server.h"
#ifndef min
# define min(a,b) ((a) < (b) ? (a) : (b))
#endif
#define PIDFILE "/tmp/fakesmtp.pid"
#define LINESIZE 1024
enum {
/* Processing top-level SMTP commands (e.g. EHLO, DATA). */
SMTP_TOP,
/* Processing payload of a DATA command. */
SMTP_DATA,
/* Looking for the blank line required by XOAUTH2 after 334 response. */
SMTP_XOAUTH_ERR
};
static int getsmtp(int, char *);
int
main(int argc, char *argv[])
{
int rc, conn, smtp_state;
FILE *f;
const char *xoauth = getenv("XOAUTH");
const char *smtputf8 = getenv("SMTPUTF8");
if (argc != 3) {
fprintf(stderr, "Usage: %s output-filename port\n", argv[0]);
exit(1);
}
if (!(f = fopen(argv[1], "w"))) {
fprintf(stderr, "Unable to open output file \"%s\": %s\n",
argv[1], strerror(errno));
exit(1);
}
conn = serve(PIDFILE, argv[2]);
/*
* Pretend to be an SMTP server.
*/
putcrlf(conn, "220 Not really an ESMTP server");
smtp_state = SMTP_TOP;
for (;;) {
char line[LINESIZE];
rc = getsmtp(conn, line);
if (rc == -1)
break; /* EOF */
fputs(line, f);
putc('\n', f);
switch (smtp_state) {
case SMTP_DATA:
if (strcmp(line, ".") == 0) {
smtp_state = SMTP_TOP;
putcrlf(conn, "250 Thanks for the info!");
}
continue;
case SMTP_XOAUTH_ERR:
smtp_state = SMTP_TOP;
putcrlf(conn, "535 Not no way, not no how!");
continue;
}
/*
* Most commands we ignore and send the same response to.
*/
if (strcmp(line, "QUIT") == 0) {
fclose(f);
f = NULL;
putcrlf(conn, "221 Later alligator!");
close(conn);
break;
}
if (strcmp(line, "DATA") == 0) {
putcrlf(conn, "354 Go ahead");
smtp_state = SMTP_DATA;
continue;
}
if (strncmp(line, "EHLO", 4) == 0) {
putcrlf(conn, "250-ready");
if (smtputf8 != NULL) {
putcrlf(conn, "250-8BITMIME");
putcrlf(conn, "250-SMTPUTF8");
}
if (xoauth != NULL) {
putcrlf(conn, "250-AUTH XOAUTH2");
}
putcrlf(conn, "250 I'll buy that for a dollar!");
continue;
}
if (xoauth != NULL) {
/* XOAUTH2 support enabled; handle AUTH (and EHLO above). */
if (strncmp(line, "AUTH", 4) == 0) {
if (strncmp(line, "AUTH XOAUTH2", 12) == 0
&& strstr(line, xoauth) != NULL) {
putcrlf(conn, "235 OK come in");
continue;
}
putcrlf(conn, "334 base64-json-err");
smtp_state = SMTP_XOAUTH_ERR;
continue;
}
}
putcrlf(conn, "250 I'll buy that for a dollar!");
}
if (f)
fclose(f);
exit(0);
}
/*
* Read a line (up to the \r\n)
*/
static int
getsmtp(int socket, char *data)
{
int cc;
static unsigned int bytesinbuf = 0;
static char buffer[LINESIZE * 2], *p;
for (;;) {
/*
* Find our \r\n
*/
if (bytesinbuf > 0 && (p = strchr(buffer, '\r')) &&
*(p + 1) == '\n') {
*p = '\0';
cc = strlen(buffer);
memcpy(data, buffer, min(cc + 1, LINESIZE));
data[LINESIZE - 1] = '\0';
/*
* Shuffle leftover bytes back to the beginning
*/
bytesinbuf -= cc + 2; /* Don't forget \r\n */
if (bytesinbuf > 0) {
memmove(buffer, buffer + cc + 2, bytesinbuf);
}
return cc;
}
if (bytesinbuf >= sizeof(buffer)) {
fprintf(stderr, "Buffer overflow in getsmtp()!\n");
exit(1);
}
memset(buffer + bytesinbuf, 0, sizeof(buffer) - bytesinbuf);
cc = read(socket, buffer + bytesinbuf,
sizeof(buffer) - bytesinbuf);
if (cc < 0) {
fprintf(stderr, "Read failed: %s\n", strerror(errno));
exit(1);
}
if (cc == 0)
return -1;
bytesinbuf += cc;
}
}
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