imapd.c

广泛使用的邮件服务器！同时

/* ========================================================================
 * Copyright 1988-2008 University of Washington
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 
 * ========================================================================
 */

/*
 * Program:	IMAP4rev1 server
 *
 * Author:	Mark Crispin
 *		UW Technology
 *		University of Washington
 *		Seattle, WA  98195
 *		Internet: [e-mail]
 *
 * Date:	5 November 1990
 * Last Edited:	3 March 2008
 */

/* Parameter files */

#include <stdio.h>
#include <ctype.h>
#include <errno.h>
extern int errno;		/* just in case */
#include <signal.h>
#include <setjmp.h>
#include <time.h>
#include "c-client.h"
#include "newsrc.h"
#include <sys/stat.h>


#define CRLF PSOUT ("\015\012")	/* primary output terpri */


/* Timeouts and timers */

#define MINUTES *60

#define LOGINTIMEOUT 3 MINUTES	/* not logged in autologout timer */
#define TIMEOUT 30 MINUTES	/* RFC 3501 minimum autologout timer */
#define INPUTTIMEOUT 5 MINUTES	/* timer for additional command input */
#define ALERTTIMER 1 MINUTES	/* alert check timer */
#define SHUTDOWNTIMER 1 MINUTES	/* shutdown dally timer */
#define IDLETIMER 1 MINUTES	/* IDLE command poll timer */
#define CHECKTIMER 15 MINUTES	/* IDLE command last checkpoint timer */


#define LITSTKLEN 20		/* length of literal stack */
#define MAXCLIENTLIT 10000	/* maximum non-APPEND client literal size
				 * must be smaller than 4294967295
				 */
#define MAXAPPENDTXT 0x40000000	/* maximum APPEND literal size
				 * must be smaller than 4294967295
				 */
#define CMDLEN 65536		/* size of command buffer */


/* Server states */

#define LOGIN 0
#define SELECT 1
#define OPEN 2
#define LOGOUT 3

/* Body text fetching */

typedef struct text_args {
  char *section;		/* body section */
  STRINGLIST *lines;		/* header lines */
  unsigned long first;		/* first octet to fetch */
  unsigned long last;		/* number of octets to fetch */
  long flags;			/* fetch flags */
  long binary;			/* binary flags */
} TEXTARGS;

#define FTB_BINARY 0x1		/* fetch as binary */
#define FTB_SIZE 0x2		/* fetch size only */


/* Append data */

typedef struct append_data {
  unsigned char *arg;		/* append argument pointer */
  char *flags;			/* message flags */
  char *date;			/* message date */
  char *msg;			/* message text */
  STRING *message;		/* message stringstruct */
} APPENDDATA;


/* Message pointer */

typedef struct msg_data {
  MAILSTREAM *stream;		/* stream */
  unsigned long msgno;		/* message number */
  char *flags;			/* current flags */
  char *date;			/* current date */
  STRING *message;		/* stringstruct of message */
} MSGDATA;

/* Function prototypes */

int main (int argc,char *argv[]);
void ping_mailbox (unsigned long uid);
time_t palert (char *file,time_t oldtime);
void msg_string_init (STRING *s,void *data,unsigned long size);
char msg_string_next (STRING *s);
void msg_string_setpos (STRING *s,unsigned long i);
void new_flags (MAILSTREAM *stream);
void settimeout (unsigned int i);
void clkint (void);
void kodint (void);
void hupint (void);
void trmint (void);
void staint (void);
char *sout (char *s,char *t);
char *nout (char *s,unsigned long n,unsigned long base);
void slurp (char *s,int n,unsigned long timeout);
void inliteral (char *s,unsigned long n);
unsigned char *flush (void);
void ioerror (FILE *f,char *reason);
unsigned char *parse_astring (unsigned char **arg,unsigned long *i,
			      unsigned char *del);
unsigned char *snarf (unsigned char **arg);
unsigned char *snarf_base64 (unsigned char **arg);
unsigned char *snarf_list (unsigned char **arg);
STRINGLIST *parse_stringlist (unsigned char **s,int *list);
unsigned long uidmax (MAILSTREAM *stream);
long parse_criteria (SEARCHPGM *pgm,unsigned char **arg,unsigned long maxmsg,
		     unsigned long maxuid,unsigned long depth);
long parse_criterion (SEARCHPGM *pgm,unsigned char **arg,unsigned long msgmsg,
		      unsigned long maxuid,unsigned long depth);
long crit_date (unsigned short *date,unsigned char **arg);
long crit_date_work (unsigned short *date,unsigned char **arg);
long crit_set (SEARCHSET **set,unsigned char **arg,unsigned long maxima);
long crit_number (unsigned long *number,unsigned char **arg);
long crit_string (STRINGLIST **string,unsigned char **arg);

void fetch (char *t,unsigned long uid);
typedef void (*fetchfn_t) (unsigned long i,void *args);
void fetch_work (char *t,unsigned long uid,fetchfn_t f[],void *fa[]);
void fetch_bodystructure (unsigned long i,void *args);
void fetch_body (unsigned long i,void *args);
void fetch_body_part_mime (unsigned long i,void *args);
void fetch_body_part_contents (unsigned long i,void *args);
void fetch_body_part_binary (unsigned long i,void *args);
void fetch_body_part_header (unsigned long i,void *args);
void fetch_body_part_text (unsigned long i,void *args);
void remember (unsigned long uid,char *id,SIZEDTEXT *st);
void fetch_envelope (unsigned long i,void *args);
void fetch_encoding (unsigned long i,void *args);
void changed_flags (unsigned long i,int f);
void fetch_flags (unsigned long i,void *args);
void put_flag (int *c,char *s);
void fetch_internaldate (unsigned long i,void *args);
void fetch_uid (unsigned long i,void *args);
void fetch_rfc822 (unsigned long i,void *args);
void fetch_rfc822_header (unsigned long i,void *args);
void fetch_rfc822_size (unsigned long i,void *args);
void fetch_rfc822_text (unsigned long i,void *args);
void penv (ENVELOPE *env);
void pbodystructure (BODY *body);
void pbody (BODY *body);
void pparam (PARAMETER *param);
void paddr (ADDRESS *a);
void pset (SEARCHSET **set);
void pnum (unsigned long i);
void pstring (char *s);
void pnstring (char *s);
void pastring (char *s);
void psizedquoted (SIZEDTEXT *s);
void psizedliteral (SIZEDTEXT *s,STRING *st);
void psizedstring (SIZEDTEXT *s,STRING *st);
void psizedastring (SIZEDTEXT *s);
void pastringlist (STRINGLIST *s);
void pnstringorlist (STRINGLIST *s);
void pbodypartstring (unsigned long msgno,char *id,SIZEDTEXT *st,STRING *bs,
		      TEXTARGS *ta);
void ptext (SIZEDTEXT *s,STRING *st);
void pthread (THREADNODE *thr);
void pcapability (long flag);
long nameok (char *ref,char *name);
char *bboardname (char *cmd,char *name);
long isnewsproxy (char *name);
long newsproxypattern (char *ref,char *pat,char *pattern,long flag);
char *imap_responder (void *challenge,unsigned long clen,unsigned long *rlen);
long proxycopy (MAILSTREAM *stream,char *sequence,char *mailbox,long options);
long proxy_append (MAILSTREAM *stream,void *data,char **flags,char **date,
		   STRING **message);
long append_msg (MAILSTREAM *stream,void *data,char **flags,char **date,
		 STRING **message);
void copyuid (MAILSTREAM *stream,char *mailbox,unsigned long uidvalidity,
	      SEARCHSET *sourceset,SEARCHSET *destset);
void appenduid (char *mailbox,unsigned long uidvalidity,SEARCHSET *set);
char *referral (MAILSTREAM *stream,char *url,long code);
void mm_list_work (char *what,int delimiter,char *name,long attributes);
char *lasterror (void);

/* Global storage */

char *version = "404";		/* edit number of this server */
char *logout = "Logout";	/* syslogreason for logout */
char *goodbye = NIL;		/* bye reason */
time_t alerttime = 0;		/* time of last alert */
time_t sysalerttime = 0;	/* time of last system alert */
time_t useralerttime = 0;	/* time of last user alert */
time_t lastcheck = 0;		/* time of last checkpoint */
time_t shutdowntime = 0;	/* time of last shutdown */
int state = LOGIN;		/* server state */
int cancelled = NIL;		/* authenticate cancelled */
int trycreate = 0;		/* saw a trycreate */
int finding = NIL;		/* doing old FIND command */
int anonymous = 0;		/* non-zero if anonymous */
int critical = NIL;		/* non-zero if in critical code */
int quell_events = NIL;		/* non-zero if in FETCH response */
int existsquelled = NIL;	/* non-zero if an EXISTS was quelled */
int proxylist = NIL;		/* doing a proxy LIST */
MAILSTREAM *stream = NIL;	/* mailbox stream */
DRIVER *curdriver = NIL;	/* note current driver */
MAILSTREAM *tstream = NIL;	/* temporary mailbox stream */
unsigned int nflags = 0;	/* current number of keywords */
unsigned long nmsgs =0xffffffff;/* last reported # of messages and recent */
unsigned long recent = 0xffffffff;
char *nntpproxy = NIL;		/* NNTP proxy name */
unsigned char *user = NIL;	/* user name */
unsigned char *pass = NIL;	/* password */
unsigned char *initial = NIL;	/* initial response */
unsigned char cmdbuf[CMDLEN];	/* command buffer */
char *status = "starting up";	/* server status */
char *tag;			/* tag portion of command */
unsigned char *cmd;		/* command portion of command */
unsigned char *arg;		/* pointer to current argument of command */
char *lstwrn = NIL;		/* last warning message from c-client */
char *lsterr = NIL;		/* last error message from c-client */
char *lstref = NIL;		/* last referral from c-client */
char *response = NIL;		/* command response */
struct {
  unsigned long size;		/* size of current LITERAL+ */
  unsigned int ok : 1;		/* LITERAL+ in effect */
} litplus;
int litsp = 0;			/* literal stack pointer */
char *litstk[LITSTKLEN];	/* stack to hold literals */
unsigned long uidvalidity = 0;	/* last reported UID validity */
unsigned long lastuid = 0;	/* last fetched uid */
char *lastid = NIL;		/* last fetched body id for this message */
char *lastsel = NIL;		/* last selected mailbox name */
SIZEDTEXT lastst = {NIL,0};	/* last sizedtext */
unsigned long cauidvalidity = 0;/* UIDVALIDITY for COPYUID/APPENDUID */
SEARCHSET *csset = NIL;		/* COPYUID source set */
SEARCHSET *caset = NIL;		/* COPYUID/APPENDUID destination set */
jmp_buf jmpenv;			/* stack context for setjmp */


/* Response texts which appear in multiple places */

char *win = "%.80s OK ";
char *rowin = "%.80s OK [READ-ONLY] %.80s completed\015\012";
char *rwwin = "%.80s OK [READ-WRITE] %.80s completed\015\012";
char *lose = "%.80s NO ";
char *logwin = "%.80s OK [";
char *losetry = "%.80s NO [TRYCREATE] %.80s failed: %.900s\015\012";
char *loseunknowncte = "%.80s NO [UNKNOWN-CTE] %.80s failed: %.900s\015\012";
char *badcmd = "%.80s BAD Command unrecognized: %.80s\015\012";
char *misarg = "%.80s BAD Missing or invalid argument to %.80s\015\012";
char *badarg = "%.80s BAD Argument given to %.80s when none expected\015\012";
char *badseq = "%.80s BAD Bogus sequence in %.80s: %.80s\015\012";
char *badatt = "%.80s BAD Bogus attribute list in %.80s\015\012";
char *badbin = "%.80s BAD Syntax error in binary specifier\015\012";

/* Message string driver for message stringstructs */

STRINGDRIVER msg_string = {
  msg_string_init,		/* initialize string structure */
  msg_string_next,		/* get next byte in string structure */
  msg_string_setpos		/* set position in string structure */
};

/* Main program */

int main (int argc,char *argv[])
{
  unsigned long i,uid;
  long f;
  unsigned char *s,*t,*u,*v,tmp[MAILTMPLEN];
  struct stat sbuf;
  logouthook_t lgoh;
  int ret = 0;
  time_t autologouttime = 0;
  char *pgmname;
				/* if case we get borked immediately */
  if (setjmp (jmpenv)) _exit (1);
  pgmname = (argc && argv[0]) ?
    (((s = strrchr (argv[0],'/')) || (s = strrchr (argv[0],'\\'))) ?
     (char *) s+1 : argv[0]) : "imapd";
				/* set service name before linkage */
  mail_parameters (NIL,SET_SERVICENAME,(void *) "imap");
#include "linkage.c"
  rfc822_date (tmp);		/* get date/time at startup */
				/* initialize server */
  server_init (pgmname,"imap","imaps",clkint,kodint,hupint,trmint,staint);
				/* forbid automatic untagged expunge */
  mail_parameters (NIL,SET_EXPUNGEATPING,NIL);
				/* arm proxy copy callback */
  mail_parameters (NIL,SET_MAILPROXYCOPY,(void *) proxycopy);
				/* arm referral callback */
  mail_parameters (NIL,SET_IMAPREFERRAL,(void *) referral);
				/* arm COPYUID callback */
  mail_parameters (NIL,SET_COPYUID,(void *) copyuid);
				/* arm APPENDUID callback */
  mail_parameters (NIL,SET_APPENDUID,(void *) appenduid);

  if (stat (SHUTDOWNFILE,&sbuf)) {
    char proxy[MAILTMPLEN];
    FILE *nntp = fopen (NNTPFILE,"r");
    if (nntp) {			/* desire NNTP proxy? */
      if (fgets (proxy,MAILTMPLEN,nntp)) {
				/* remove newline and set NNTP proxy */
	if (s = strchr (proxy,'\n')) *s = '\0';
	nntpproxy = cpystr (proxy);
				/* disable the news driver */
	mail_parameters (NIL,DISABLE_DRIVER,"news");
      }
      fclose (nntp);		/* done reading proxy name */
    }
    s = myusername_full (&i);	/* get user name and flags */
    switch (i) {
    case MU_NOTLOGGEDIN:
      PSOUT ("* OK [");		/* not logged in, ordinary startup */
      pcapability (-1);
      break;
    case MU_ANONYMOUS:
      anonymous = T;		/* anonymous user, fall into default */
      s = "ANONYMOUS";
    case MU_LOGGEDIN:
      PSOUT ("* PREAUTH [");	/* already logged in, pre-authorized */
      pcapability (1);
      user = cpystr (s);	/* copy user name */
      pass = cpystr ("*");	/* set fake password */
      state = SELECT;		/* enter select state */
      break;
    default:
      fatal ("Unknown state from myusername_full()");
    }
    PSOUT ("] ");
    if (user) {			/* preauthenticated as someone? */
      PSOUT ("Pre-authenticated user ");
      PSOUT (user);
      PBOUT (' ');
    }
  }
  else {			/* login disabled */
    PSOUT ("* BYE Service not available ");
    state = LOGOUT;
  }
  PSOUT (tcp_serverhost ());
  PSOUT (" IMAP4rev1 ");
  PSOUT (CCLIENTVERSION);
  PBOUT ('.');
  PSOUT (version);
  PSOUT (" at ");
  PSOUT (tmp);
  CRLF;
  PFLUSH ();			/* dump output buffer */
  switch (state) {		/* do this after the banner */
  case LOGIN:
    autologouttime = time (0) + LOGINTIMEOUT;
    break;
  case SELECT:
    syslog (LOG_INFO,"Preauthenticated user=%.80s host=%.80s",
	    user,tcp_clienthost ());
    break;
  }

  if (setjmp (jmpenv)) {	/* die if a signal handler say so */
				/* in case we get borked now */
    if (setjmp (jmpenv)) _exit (1);
				/* need to close stream gracefully? */
    if (stream && !stream->lock && (stream->dtb->flags & DR_XPOINT))
      stream = mail_close (stream);
    ret = 1;			/* set exit status */
  }
  else while (state != LOGOUT) {/* command processing loop */
    slurp (cmdbuf,CMDLEN,TIMEOUT);