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         const char *smtputf8 = getenv("SMTPUTF8");
  45
  46         if (argc != 3) {
  47                 fprintf(stderr, "Usage: %s output-filename port\n", argv[0]);
  48                 exit(1);
  49         }
  50
  51         if (!(f = fopen(argv[1], "w"))) {
  52                 fprintf(stderr, "Unable to open output file \"%s\": %s\n",
  53                         argv[1], strerror(errno));
  54                 exit(1);
  55         }
  56
  57         conn = serve(PIDFILE, argv[2]);
  58
  59         /*
  60          * Pretend to be an SMTP server.
  61          */
  62
  63         putcrlf(conn, "220 Not really an ESMTP server");
  64         smtp_state = SMTP_TOP;
  65
  66         for (;;) {
  67                 char line[LINESIZE];
  68
  69                 rc = getsmtp(conn, line);
  70
  71                 if (rc == -1)
  72                         break;  /* EOF */
  73
  74                 fputs(line, f);
  75                 putc('\n', f);
  76
  77                 switch (smtp_state) {
  78                 case SMTP_DATA:
  79                         if (strcmp(line, ".") == 0) {
  80                                 smtp_state = SMTP_TOP;
  81                                 putcrlf(conn, "250 Thanks for the info!");
  82                         }
  83                         continue;
  84                 case SMTP_XOAUTH_ERR:
  85                         smtp_state = SMTP_TOP;
  86                         putcrlf(conn, "535 Not no way, not no how!");
  87                         continue;
  88                 }
  89
  90                 /*
  91                  * Most commands we ignore and send the same response to.
  92                  */
  93
  94                 if (strcmp(line, "QUIT") == 0) {
  95                         fclose(f);
  96                         f = NULL;
  97                         putcrlf(conn, "221 Later alligator!");
  98                         close(conn);
  99                         break;
 100                 }
 101                 if (strcmp(line, "DATA") == 0) {
 102                         putcrlf(conn, "354 Go ahead");
 103                         smtp_state = SMTP_DATA;
 104                         continue;
 105                 }
 106                 if (strncmp(line, "EHLO", 4) == 0) {
 107                         putcrlf(conn, "250-ready");
 108                         if (smtputf8 != NULL) {
 109                                 putcrlf(conn, "250-8BITMIME");
 110                                 putcrlf(conn, "250-SMTPUTF8");
 111                         }
 112                         if (xoauth != NULL) {
 113                                 putcrlf(conn, "250-AUTH XOAUTH2");
 114                         }
 115                         putcrlf(conn, "250 I'll buy that for a dollar!");
 116                         continue;
 117                 }
 118                 if (xoauth != NULL) {
 119                         /* XOAUTH2 support enabled; handle AUTH (and EHLO above). */
 120                         if (strncmp(line, "AUTH", 4) == 0) {
 121                                 if (strncmp(line, "AUTH XOAUTH2", 12) == 0
 122                                     && strstr(line, xoauth) != NULL) {
 123                                         putcrlf(conn, "235 OK come in");
 124                                         continue;
 125                                 }
 126                                 putcrlf(conn, "334 base64-json-err");
 127                                 smtp_state = SMTP_XOAUTH_ERR;
 128                                 continue;
 129                         }
 130                 }
 131                 putcrlf(conn, "250 I'll buy that for a dollar!");
 132         }
 133
 134         if (f)
 135                 fclose(f);
 136
 137         exit(0);
 138 }
 139
 140 /*
 141  * Read a line (up to the \r\n)
 142  */
 143
 144 static int
 145 getsmtp(int socket, char *data)
 146 {
 147         int cc;
 148         static unsigned int bytesinbuf = 0;
 149         static char buffer[LINESIZE * 2], *p;
 150
 151         for (;;) {
 152                 /*
 153                  * Find our \r\n
 154                  */
 155
 156                 if (bytesinbuf > 0 && (p = strchr(buffer, '\r')) &&
 157                                                         *(p + 1) == '\n') {
 158                         *p = '\0';
 159                         strncpy(data, buffer, LINESIZE);
 160                         data[LINESIZE - 1] = '\0';
 161                         cc = strlen(buffer);
 162
 163                         /*
 164                          * Shuffle leftover bytes back to the beginning
 165                          */
 166
 167                         bytesinbuf -= cc + 2;   /* Don't forget \r\n */
 168                         if (bytesinbuf > 0) {
 169                                 memmove(buffer, buffer + cc + 2, bytesinbuf);
 170                         }
 171                         return cc;
 172                 }
 173
 174                 if (bytesinbuf >= sizeof(buffer)) {
 175                         fprintf(stderr, "Buffer overflow in getsmtp()!\n");
 176                         exit(1);
 177                 }
 178
 179                 memset(buffer + bytesinbuf, 0, sizeof(buffer) - bytesinbuf);
 180                 cc = read(socket, buffer + bytesinbuf,
 181                           sizeof(buffer) - bytesinbuf);
 182
 183                 if (cc < 0) {
 184                         fprintf(stderr, "Read failed: %s\n", strerror(errno));
 185                         exit(1);
 186                 }
 187
 188                 if (cc == 0)
 189                         return -1;
 190
 191                 bytesinbuf += cc;
 192         }
 193 }