/* Copyright 1996 by Eric S. Raymond * All rights reserved. * For license terms, see the file COPYING in this directory. */ /*********************************************************************** module: driver.c project: fetchmail programmer: Eric S. Raymond description: Generic driver for mail fetch method protocols ***********************************************************************/ #include #include #include #include #include #ifdef HAVE_RRESVPORT_H #include #endif /* HAVE_RRESVPORT_H */ #include "socket.h" #include "fetchmail.h" #include "smtp.h" static struct method *protocol; #define SMTP_PORT 25 /* standard SMTP service port */ char tag[TAGLEN]; static int tagnum; #define GENSYM (sprintf(tag, "a%04d", ++tagnum), tag) /********************************************************************* function: description: hack message headers so replies will work properly arguments: after where to put the hacked header before header to hack host name of the pop header return value: none. calls: none. *********************************************************************/ static void reply_hack(buf, host) /* hack local mail IDs -- code by Eric S. Raymond 20 Jun 1996 */ char *buf; const char *host; { const char *from; int state = 0; char mycopy[POPBUFSIZE+1]; if (strncmp("From: ", buf, 6) && strncmp("To: ", buf, 4) && strncmp("Reply-", buf, 6) && strncmp("Cc: ", buf, 4) && strncmp("Bcc: ", buf, 5)) { return; } strcpy(mycopy, buf); for (from = mycopy; *from; from++) { switch (state) { case 0: /* before header colon */ if (*from == ':') state = 1; break; case 1: /* we've seen the colon, we're looking for addresses */ if (*from == '"') state = 2; else if (*from == '(') state = 3; else if (*from == '<' || isalnum(*from)) state = 4; break; case 2: /* we're in a quoted human name, copy and ignore */ if (*from == '"') state = 1; break; case 3: /* we're in a parenthesized human name, copy and ignore */ if (*from == ')') state = 1; break; case 4: /* the real work gets done here */ /* * We're in something that might be an address part, * either a bare unquoted/unparenthesized text or text * enclosed in <> as per RFC822. */ /* if the address part contains an @, don't mess with it */ if (*from == '@') state = 5; /* If the address token is not properly terminated, ignore it. */ else if (*from == ' ' || *from == '\t') state = 1; /* * On proper termination with no @, insert hostname. * Case '>' catches <>-enclosed mail IDs. Case ',' catches * comma-separated bare IDs. Cases \r and \n catch the case * of a single ID alone on the line. */ else if (strchr(">,\r\n", *from)) { strcpy(buf, "@"); strcat(buf, host); buf += strlen(buf); state = 1; } /* everything else, including alphanumerics, just passes through */ break; case 5: /* we're in a remote mail ID, no need to append hostname */ if (*from == '>' || *from == ',' || isspace(*from)) state = 1; break; } /* all characters from the old buffer get copied to the new one */ *buf++ = *from; } *buf++ = '\0'; } /********************************************************************* function: nxtaddr description: Parse addresses in succession out of a specified RFC822 header. Note 1: RFC822 escaping with \ is *not* handled. Note 2: it is important that this routine not stop on \r, since we use \r as a marker for RFC822 continuations below. arguments: hdr header line to be parsed, NUL to continue in previous hdr return value: next address, or NUL if there is no next address calls: none *********************************************************************/ static char *nxtaddr(hdr) char *hdr; { static char *hp, *tp, address[POPBUFSIZE+1]; static state; if (hdr) { hp = hdr; state = 0; } for (; *hp; hp++) { switch (state) { case 0: /* before header colon */ if (*hp == '\n') return(NULL); else if (*hp == ':') { state = 1; tp = address; } break; case 1: /* we've seen the colon, now grab the address */ if ((*hp == '\n') || (*hp == ',')) /* end of address list */ { *tp++ = '\0'; return(address); } else if (*hp == '"') /* quoted string */ { state = 2; *tp++ = *hp; } else if (*hp == '(') /* address comment -- ignore */ state = 3; else if (*hp == '<') /* begin
*/ { state = 4; tp = address; } else if (isspace(*hp)) /* ignore space */ state = 1; else /* just take it */ { state = 1; *tp++ = *hp; } break; case 2: /* we're in a quoted string, copy verbatim */ if (*hp == '\n') return(NULL); if (*hp != '"') *tp++ = *hp; else if (*hp == '"') { *tp++ = *hp; state = 1; } break; case 3: /* we're in a parenthesized comment, ignore */ if (*hp == '\n') return(NULL); else if (*hp == ')') state = 1; break; case 4: /* possible <>-enclosed address */ if (*hp == '>') /* end of address */ { *tp++ = '\0'; state = 1; return(address); } else if (*hp == '<') /* nested <> */ tp = address; else if (*hp == '"') /* quoted address */ { *tp++ = *hp; state = 5; } else /* just copy address */ *tp++ = *hp; break; case 5: /* we're in a quoted address, copy verbatim */ if (*hp == '\n') /* mismatched quotes */ return(NULL); if (*hp != '"') /* just copy it if it isn't a quote */ *tp++ = *hp; else if (*hp == '"') /* end of quoted string */ { *tp++ = *hp; state = 4; } break; } } return(NULL); } /********************************************************************* function: gen_readmsg description: Read the message content as described in RFC 1225. arguments: socket ... to which the server is connected. mboxfd open file descriptor to which the retrieved message will be written. len length of text delimited does the protocol use a message delimiter? queryctl host control block return value: zero if success else PS_* return code. calls: SockGets. globals: reads outlevel. *********************************************************************/ static int gen_readmsg (socket, mboxfd, len, delimited, queryctl) int socket; int mboxfd; long len; int delimited; struct hostrec *queryctl; { char buf [MSGBUFSIZE+1]; char fromBuf[MSGBUFSIZE+1]; char *bufp, *headers, *unixfrom, *fromhdr, *tohdr, *cchdr, *bcchdr; int n, oldlen; int inheaders; int lines,sizeticker; time_t now; /* This keeps the retrieved message count for display purposes */ static int msgnum = 0; /* set up for status message if outlevel allows it */ if (outlevel > O_SILENT && outlevel < O_VERBOSE) fprintf(stderr,"reading message %d",++msgnum); /* read the message content from the server */ inheaders = 1; headers = unixfrom = fromhdr = tohdr = cchdr = bcchdr = NULL; lines = 0; sizeticker = 0; while (delimited || len > 0) { if ((n = SockGets(socket,buf,sizeof(buf))) < 0) return(PS_SOCKET); len -= n; bufp = buf; if (buf[0] == '\0' || buf[0] == '\r' || buf[0] == '\n') inheaders = 0; if (*bufp == '.') { bufp++; if (delimited && *bufp == 0) break; /* end of message */ } strcat(bufp, "\n"); if (inheaders) { if (!queryctl->norewrite) reply_hack(bufp, queryctl->servername); if (!lines) { oldlen = strlen(bufp); headers = malloc(oldlen + 1); if (headers == NULL) return(PS_IOERR); (void) strcpy(headers, bufp); bufp = headers; } else { int newlen; /* * We deal with RFC822 continuation lines here. * Replace previous '\n' with '\r' so nxtaddr * and reply_hack will be able to see past it. * (We know this safe because SocketGets stripped * out all carriage returns in the read loop above * and we haven't reintroduced any since then.) * We'll undo this before writing the header. */ if (isspace(bufp[0])) headers[oldlen-1] = '\r'; newlen = oldlen + strlen(bufp); headers = realloc(headers, newlen + 1); if (headers == NULL) return(PS_IOERR); strcpy(headers + oldlen, bufp); bufp = headers + oldlen; oldlen = newlen; } if (!strncmp(bufp,"From ",5)) unixfrom = bufp; else if (!strncasecmp("From: ", bufp, 6)) fromhdr = bufp; else if (!strncasecmp("To: ", bufp, 4)) tohdr = bufp; else if (!strncasecmp("Cc: ", bufp, 4)) cchdr = bufp; else if (!strncasecmp("Bcc: ", bufp, 5)) bcchdr = bufp; goto skipwrite; } else if (headers) { char *cp; if (!queryctl->mda[0]) { if (SMTP_from(mboxfd, nxtaddr(fromhdr)) != SM_OK) return(PS_SMTP); #ifdef SMTP_RESEND /* * This is what we'd do if fetchmail were a real MDA * a la sendmail -- crack all the destination headers * and send to every address we can reach via SMTP. */ if (tohdr && (cp = nxtaddr(tohdr)) != (char *)NULL) do { if (SMTP_rcpt(mboxfd, cp) == SM_UNRECOVERABLE) return(PS_SMTP); } while (cp = nxtaddr(NULL)); if (cchdr && (cp = nxtaddr(cchdr)) != (char *)NULL) do { if (SMTP_rcpt(mboxfd, cp) == SM_UNRECOVERABLE) return(PS_SMTP); } while (cp = nxtaddr(NULL)); if (bcchdr && (cp = nxtaddr(bcchdr)) != (char *)NULL) do { if (SMTP_rcpt(mboxfd, cp) == SM_UNRECOVERABLE) return(PS_SMTP); } while (cp = nxtaddr(NULL)); #else /* * Since we're really only fetching mail for one user * per host query, we can be simpler */ if (SMTP_rcpt(mboxfd, queryctl->localname) == SM_UNRECOVERABLE) return(PS_SMTP); #endif /* SMTP_RESEND */ SMTP_data(mboxfd); if (outlevel == O_VERBOSE) fputs("SMTP> ", stderr); } /* change continuation markers back to regular newlines */ for (cp = headers; cp < headers + oldlen; cp++) if (*cp == '\r') *cp = '\n'; /* * Strictly speaking, we ought to replace all LFs * with CR-LF before shipping to an SMTP listener. * Since most SMTP listeners built since the mid-1980s * (and *all* Unix listeners) accept lone LF as equivalent * to CR-LF, we'll skip this particular contortion. */ if (write(mboxfd,headers,oldlen) < 0) { free(headers); headers = NULL; perror("gen_readmsg: writing RFC822 headers"); return(PS_IOERR); } else if (outlevel == O_VERBOSE) fputs("#", stderr); free(headers); headers = NULL; } /* SMTP byte-stuffing */ if (*bufp == '.' && queryctl->mda[0] == 0) write(mboxfd, ".", 1); /* write this line to the file -- comment about CR-LF vs. LF applies */ if (write(mboxfd,bufp,strlen(bufp)) < 0) { perror("gen_readmsg: writing message text"); return(PS_IOERR); } else if (outlevel == O_VERBOSE) fputc('*', stderr); skipwrite:; /* write the message size dots */ sizeticker += strlen(bufp); while (sizeticker >= SIZETICKER) { if (outlevel > O_SILENT && outlevel < O_VERBOSE) fputc('.',stderr); sizeticker -= SIZETICKER; } lines++; } /* finish up display output */ if (outlevel == O_VERBOSE) fprintf(stderr,"\n(%d lines of message content)\n",lines); else if (outlevel > O_SILENT) fputs("\n", stderr); /* write message terminator */ if (!queryctl->mda[0]) if (SMTP_eom(mboxfd) != SM_OK) return(PS_SMTP); return(0); } /********************************************************************* function: do_protocol description: retrieve messages from the specified mail server using a given set of methods arguments: queryctl fully-specified options (i.e. parsed, defaults invoked, etc). proto protocol method pointer return value: exit code from the set of PS_.* constants defined in fetchmail.h calls: globals: reads outlevel. *********************************************************************/ int do_protocol(queryctl, proto) struct hostrec *queryctl; struct method *proto; { int ok, len; int mboxfd = -1; char buf [POPBUFSIZE+1], host[HOSTLEN+1]; int socket; #ifdef HAVE_RRESVPORT_H int privport = -1; #endif /* HAVE_RRESVPORT_H */ int num, count, deletions = 0; /* lacking methods, there are some options that may fail */ if (!proto->is_old) { /* check for unsupported options */ if (queryctl->flush) { fprintf(stderr, "Option --flush is not supported with %s\n", proto->name); return(PS_SYNTAX); } else if (queryctl->fetchall) { fprintf(stderr, "Option --all is not supported with %s\n", proto->name); return(PS_SYNTAX); } } tagnum = 0; protocol = proto; #ifdef HAVE_RRESVPORT_H /* * If we're trying to bind to a reserved port on the remote system, * do likewise on the local one so the remote will know we're privileged. * (This is most likely to happen in connection with RPOP.) */ if (queryctl->port < IPPORT_RESERVED) { ok = IPPORT_RESERVED - 1; if ((privport = rresvport(&ok)) == -1) { perror("fetchmail, binding to reserved port"); return(PS_SOCKET); } } #endif /* HAVE_RRESVPORT_H */ /* open a socket to the mail server */ if ((socket = Socket(queryctl->servername, queryctl->port ? queryctl->port : protocol->port))<0) { perror("fetchmail, connecting to host"); ok = PS_SOCKET; goto closeUp; } /* accept greeting message from mail server */ ok = (protocol->parse_response)(socket, buf); if (ok != 0) goto cleanUp; /* try to get authorized to fetch mail */ ok = (protocol->getauth)(socket, queryctl, buf); if (ok == PS_ERROR) ok = PS_AUTHFAIL; if (ok != 0) goto cleanUp; /* compute count, and get UID list if possible */ if ((protocol->getrange)(socket, queryctl, &count) != 0) goto cleanUp; /* show user how many messages we downloaded */ if (outlevel > O_SILENT && outlevel < O_VERBOSE) if (count == 0) fprintf(stderr, "No mail from %s\n", queryctl->servername); else fprintf(stderr, "%d message%s from %s.\n", count, count > 1 ? "s" : "", queryctl->servername); if (count > 0) { if (queryctl->mda[0] == '\0') if ((mboxfd = Socket(queryctl->smtphost, SMTP_PORT)) < 0 || SMTP_ok(mboxfd, NULL) != SM_OK || SMTP_helo(mboxfd, queryctl->servername) != SM_OK) { ok = PS_SMTP; close(mboxfd); mboxfd = -1; goto cleanUp; } /* read, forward, and delete messages */ for (num = 1; num <= count; num++) { int treat_as_new = !protocol->is_old || !(protocol->is_old)(socket, queryctl, num); /* we may want to reject this message if it's old */ if (treat_as_new || queryctl->fetchall) { /* request a message */ (protocol->fetch)(socket, num, &len); if (outlevel == O_VERBOSE) if (protocol->delimited) fprintf(stderr, "fetching message %d (delimited)\n", num); else fprintf(stderr, "fetching message %d (%d bytes)\n", num, len); /* open the delivery pipe now if we're using an MDA */ if (queryctl->mda[0]) if ((mboxfd = openmailpipe(queryctl)) < 0) goto cleanUp; /* read the message and ship it to the output sink */ ok = gen_readmsg(socket, mboxfd, len, protocol->delimited, queryctl); /* close the delivery pipe, we'll reopen before next message */ if (queryctl->mda[0]) if ((ok = closemailpipe(mboxfd)) != 0) goto cleanUp; /* tell the server we got it OK and resynchronize */ if (protocol->trail) (protocol->trail)(socket, queryctl, num); if (ok != 0) goto cleanUp; } /* * At this point in flow of control, either we've bombed * on a protocol error or had delivery refused by the SMTP * server (unlikely -- I've never seen it) or we've seen * `accepted for delivery' and the message is shipped. * It's safe to delete the message on the server now. */ /* maybe we delete this message now? */ if (protocol->delete && !queryctl->keep && (treat_as_new || queryctl->flush)) { deletions++; if (outlevel > O_SILENT && outlevel < O_VERBOSE) fprintf(stderr,"flushing message %d\n", num); ok = (protocol->delete)(socket, queryctl, num); if (ok != 0) goto cleanUp; } } /* remove all messages flagged for deletion */ if (protocol->expunge_cmd && deletions > 0) { ok = gen_transact(socket, protocol->expunge_cmd); if (ok != 0) goto cleanUp; } ok = gen_transact(socket, protocol->exit_cmd); if (ok == 0) ok = PS_SUCCESS; close(socket); goto closeUp; } else { ok = gen_transact(socket, protocol->exit_cmd); if (ok == 0) ok = PS_NOMAIL; close(socket); goto closeUp; } cleanUp: if (ok != 0 && ok != PS_SOCKET) { gen_transact(socket, protocol->exit_cmd); close(socket); } #ifdef HAVE_RRESVPORT_H if (privport != -1) close(privport); /* no big deal if this fails */ #endif /* HAVE_RRESVPORT_H */ closeUp: if (mboxfd != -1) { SMTP_quit(mboxfd); close(mboxfd); } return(ok); } /********************************************************************* function: gen_send description: Assemble command in print style and send to the server arguments: socket socket to which the server is connected. fmt printf-style format return value: none. calls: SockPuts. globals: reads outlevel. *********************************************************************/ void gen_send(socket, fmt, va_alist) int socket; const char *fmt; va_dcl { char buf [POPBUFSIZE+1]; va_list ap; if (protocol->tagged) (void) sprintf(buf, "%s ", GENSYM); else buf[0] = '\0'; va_start(ap); vsprintf(buf + strlen(buf), fmt, ap); va_end(ap); SockPuts(socket, buf); if (outlevel == O_VERBOSE) fprintf(stderr,"> %s\n", buf); } /********************************************************************* function: gen_transact description: Assemble command in print style and send to the server. then accept a protocol-dependent response. arguments: socket socket to which the server is connected. fmt printf-style format return value: none. calls: SockPuts. globals: reads outlevel. *********************************************************************/ int gen_transact(socket, fmt, va_alist) int socket; const char *fmt; va_dcl { int ok; char buf [POPBUFSIZE+1]; va_list ap; if (protocol->tagged) (void) sprintf(buf, "%s ", GENSYM); else buf[0] = '\0'; va_start(ap); vsprintf(buf + strlen(buf), fmt, ap); va_end(ap); SockPuts(socket, buf); if (outlevel == O_VERBOSE) fprintf(stderr,"> %s\n", buf); /* we presume this does its own response echoing */ ok = (protocol->parse_response)(socket, buf); return(ok); }