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

   1 /* fakesmtp - A fake SMTP server used by the nmh test suite
   2  *
   3  * This code is Copyright (c) 2012, by the authors of nmh.  See the
   4  * COPYRIGHT file in the root directory of the nmh distribution for
   5  * complete copyright information.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12 #include <errno.h>
  13 #include <sys/socket.h>
  14 #include <sys/types.h>
  15 #include <sys/stat.h>
  16
  17 #define PIDFILE "/tmp/fakesmtp.pid"
  18
  19 #define LINESIZE 1024
  20
  21 enum {
  22         /* Processing top-level SMTP commands (e.g. EHLO, DATA). */
  23         SMTP_TOP,
  24
  25         /* Processing payload of a DATA command. */
  26         SMTP_DATA,
  27
  28         /* Looking for the blank line required by XOAUTH2 after 334 response. */
  29         SMTP_XOAUTH_ERR
  30 };
  31
  32 void putcrlf(int, char *);
  33 int serve(const char *, const char *);
  34
  35 static int getsmtp(int, char *);
  36
  37 int
  38 main(int argc, char *argv[])
  39 {
  40         int rc, conn, smtp_state;
  41         FILE *f;
  42         const char *xoauth = getenv("XOAUTH");
  43         const char *smtputf8 = getenv("SMTPUTF8");
  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                 fputs(line, f);
  74                 putc('\n', f);
  75
  76                 switch (smtp_state) {
  77                 case SMTP_DATA:
  78                         if (strcmp(line, ".") == 0) {
  79                                 smtp_state = SMTP_TOP;
  80                                 putcrlf(conn, "250 Thanks for the info!");
  81                         }
  82                         continue;
  83                 case SMTP_XOAUTH_ERR:
  84                         smtp_state = SMTP_TOP;
  85                         putcrlf(conn, "535 Not no way, not no how!");
  86                         continue;
  87                 }
  88
  89                 /*
  90                  * Most commands we ignore and send the same response to.
  91                  */
  92
  93                 if (strcmp(line, "QUIT") == 0) {
  94                         fclose(f);
  95                         f = NULL;
  96                         putcrlf(conn, "221 Later alligator!");
  97                         close(conn);
  98                         break;
  99                 }
 100                 if (strcmp(line, "DATA") == 0) {
 101                         putcrlf(conn, "354 Go ahead");
 102                         smtp_state = SMTP_DATA;
 103                         continue;
 104                 }
 105                 if (strncmp(line, "EHLO", 4) == 0) {
 106                         putcrlf(conn, "250-ready");
 107                         if (smtputf8 != NULL) {
 108                                 putcrlf(conn, "250-8BITMIME");
 109                                 putcrlf(conn, "250-SMTPUTF8");
 110                         }
 111                         if (xoauth != NULL) {
 112                                 putcrlf(conn, "250-AUTH XOAUTH2");
 113                         }
 114                         putcrlf(conn, "250 I'll buy that for a dollar!");
 115                         continue;
 116                 }
 117                 if (xoauth != NULL) {
 118                         /* XOAUTH2 support enabled; handle AUTH (and EHLO above). */
 119                         if (strncmp(line, "AUTH", 4) == 0) {
 120                                 if (strncmp(line, "AUTH XOAUTH2", 12) == 0
 121                                     && strstr(line, xoauth) != NULL) {
 122                                         putcrlf(conn, "235 OK come in");
 123                                         continue;
 124                                 }
 125                                 putcrlf(conn, "334 base64-json-err");
 126                                 smtp_state = SMTP_XOAUTH_ERR;
 127                                 continue;
 128                         }
 129                 }
 130                 putcrlf(conn, "250 I'll buy that for a dollar!");
 131         }
 132
 133         if (f)
 134                 fclose(f);
 135
 136         exit(0);
 137 }
 138
 139 /*
 140  * Read a line (up to the \r\n)
 141  */
 142
 143 static int
 144 getsmtp(int socket, char *data)
 145 {
 146         int cc;
 147         static unsigned int bytesinbuf = 0;
 148         static char buffer[LINESIZE * 2], *p;
 149
 150         for (;;) {
 151                 /*
 152                  * Find our \r\n
 153                  */
 154
 155                 if (bytesinbuf > 0 && (p = strchr(buffer, '\r')) &&
 156                                                         *(p + 1) == '\n') {
 157                         *p = '\0';
 158                         strncpy(data, buffer, LINESIZE);
 159                         data[LINESIZE - 1] = '\0';
 160                         cc = strlen(buffer);
 161
 162                         /*
 163                          * Shuffle leftover bytes back to the beginning
 164                          */
 165
 166                         bytesinbuf -= cc + 2;   /* Don't forget \r\n */
 167                         if (bytesinbuf > 0) {
 168                                 memmove(buffer, buffer + cc + 2, bytesinbuf);
 169                         }
 170                         return cc;
 171                 }
 172
 173                 if (bytesinbuf >= sizeof(buffer)) {
 174                         fprintf(stderr, "Buffer overflow in getsmtp()!\n");
 175                         exit(1);
 176                 }
 177
 178                 memset(buffer + bytesinbuf, 0, sizeof(buffer) - bytesinbuf);
 179                 cc = read(socket, buffer + bytesinbuf,
 180                           sizeof(buffer) - bytesinbuf);
 181
 182                 if (cc < 0) {
 183                         fprintf(stderr, "Read failed: %s\n", strerror(errno));
 184                         exit(1);
 185                 }
 186
 187                 if (cc == 0)
 188                         return -1;
 189
 190                 bytesinbuf += cc;
 191         }
 192 }