diplodocus.org Git - nmh/blob - test/fakesmtp.c

   1 /*
   2  * fakesmtp - A fake SMTP server used by the nmh test suite
   3  *
   4  * This code is Copyright (c) 2012, by the authors of nmh.  See the
   5  * COPYRIGHT file in the root directory of the nmh distribution for
   6  * complete copyright information.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <errno.h>
  14 #include <sys/socket.h>
  15 #include <sys/types.h>
  16 #include <sys/stat.h>
  17
  18 #define PIDFILE "/tmp/fakesmtp.pid"
  19
  20 #define LINESIZE 1024
  21
  22 enum {
  23         /* Processing top-level SMTP commands (e.g. EHLO, DATA). */
  24         SMTP_TOP,
  25
  26         /* Processing payload of a DATA command. */
  27         SMTP_DATA,
  28
  29         /* Looking for the blank line required by XOAUTH2 after 334 response. */
  30         SMTP_XOAUTH_ERR
  31 };
  32
  33 void putcrlf(int, char *);
  34 int serve(const char *, const char *);
  35
  36 static int getsmtp(int, char *);
  37
  38 int
  39 main(int argc, char *argv[])
  40 {
  41         int rc, conn, smtp_state;
  42         FILE *f;
  43         const char *xoauth = getenv("XOAUTH");
  44
  45         if (argc != 3) {
  46                 fprintf(stderr, "Usage: %s output-filename port\n", argv[0]);
  47                 exit(1);
  48         }
  49
  50         if (!(f = fopen(argv[1], "w"))) {
  51                 fprintf(stderr, "Unable to open output file \"%s\": %s\n",
  52                         argv[1], strerror(errno));
  53                 exit(1);
  54         }
  55
  56         conn = serve(PIDFILE, argv[2]);
  57
  58         /*
  59          * Pretend to be an SMTP server.
  60          */
  61
  62         putcrlf(conn, "220 Not really an ESMTP server");
  63         smtp_state = SMTP_TOP;
  64
  65         for (;;) {
  66                 char line[LINESIZE];
  67
  68                 rc = getsmtp(conn, line);
  69
  70                 if (rc == -1)
  71                         break;  /* EOF */
  72
  73                 fprintf(f, "%s\n", line);
  74
  75                 switch (smtp_state) {
  76                 case SMTP_DATA:
  77                         if (strcmp(line, ".") == 0) {
  78                                 smtp_state = SMTP_TOP;
  79                                 putcrlf(conn, "250 Thanks for the info!");
  80                         }
  81                         continue;
  82                 case SMTP_XOAUTH_ERR:
  83                         smtp_state = SMTP_TOP;
  84                         putcrlf(conn, "535 Not no way, not no how!");
  85                         continue;
  86                 }
  87
  88                 /*
  89                  * Most commands we ignore and send the same response to.
  90                  */
  91
  92                 if (strcmp(line, "QUIT") == 0) {
  93                         fclose(f);
  94                         f = NULL;
  95                         putcrlf(conn, "221 Later alligator!");
  96                         close(conn);
  97                         break;
  98                 }
  99                 if (strcmp(line, "DATA") == 0) {
 100                         putcrlf(conn, "354 Go ahead");
 101                         smtp_state = SMTP_DATA;
 102                         continue;
 103                 }
 104                 if (xoauth != NULL) {
 105                         /* XOAUTH2 support enabled; handle EHLO and AUTH. */
 106                         if (strncmp(line, "EHLO", 4) == 0) {
 107                                 putcrlf(conn, "250-ready");
 108                                 putcrlf(conn, "250 AUTH XOAUTH2");
 109                                 continue;
 110                         }
 111                         if (strncmp(line, "AUTH", 4) == 0) {
 112                                 if (strncmp(line, "AUTH XOAUTH2", 12) == 0
 113                                     && strstr(line, xoauth) != NULL) {
 114                                         putcrlf(conn, "235 OK come in");
 115                                         continue;
 116                                 }
 117                                 putcrlf(conn, "334 base64-json-err");
 118                                 smtp_state = SMTP_XOAUTH_ERR;
 119                                 continue;
 120                         }
 121                 }
 122                 putcrlf(conn, "250 I'll buy that for a dollar!");
 123         }
 124
 125         if (f)
 126                 fclose(f);
 127
 128         exit(0);
 129 }
 130
 131 /*
 132  * Read a line (up to the \r\n)
 133  */
 134
 135 static int
 136 getsmtp(int socket, char *data)
 137 {
 138         int cc;
 139         static unsigned int bytesinbuf = 0;
 140         static char buffer[LINESIZE * 2], *p;
 141
 142         for (;;) {
 143                 /*
 144                  * Find our \r\n
 145                  */
 146
 147                 if (bytesinbuf > 0 && (p = strchr(buffer, '\r')) &&
 148                                                         *(p + 1) == '\n') {
 149                         *p = '\0';
 150                         strncpy(data, buffer, LINESIZE);
 151                         data[LINESIZE - 1] = '\0';
 152                         cc = strlen(buffer);
 153
 154                         /*
 155                          * Shuffle leftover bytes back to the beginning
 156                          */
 157
 158                         bytesinbuf -= cc + 2;   /* Don't forget \r\n */
 159                         if (bytesinbuf > 0) {
 160                                 memmove(buffer, buffer + cc + 2, bytesinbuf);
 161                         }
 162                         return cc;
 163                 }
 164
 165                 if (bytesinbuf >= sizeof(buffer)) {
 166                         fprintf(stderr, "Buffer overflow in getsmtp()!\n");
 167                         exit(1);
 168                 }
 169
 170                 memset(buffer + bytesinbuf, 0, sizeof(buffer) - bytesinbuf);
 171                 cc = read(socket, buffer + bytesinbuf,
 172                           sizeof(buffer) - bytesinbuf);
 173
 174                 if (cc < 0) {
 175                         fprintf(stderr, "Read failed: %s\n", strerror(errno));
 176                         exit(1);
 177                 }
 178
 179                 if (cc == 0)
 180                         return -1;
 181
 182                 bytesinbuf += cc;
 183         }
 184 }