alias.c

操作系统SunOS 4.1.3版本的源码

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and that due credit is given
 * to the University of California at Berkeley. The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission. This software
 * is provided ``as is'' without express or implied warranty.
 *
 *  Sendmail
 *  Copyright (c) 1983  Eric P. Allman
 *  Berkeley, California
 */

# include <pwd.h>
# include <sys/types.h>
# include <sys/stat.h>
# include <signal.h>
# include <errno.h>
# include "sendmail.h"
# include <sys/file.h>

SCCSID(@(#)alias.c 1.1 92/07/30 SMI); /* from UCB 5.15 4/1/88 */

/*
**  ALIAS -- Compute aliases.
**
**	Scans the alias file for an alias for the given address.
**	If found, it arranges to deliver to the alias list instead.
**	Uses libdbm database if -DDBM.
**
**	Parameters:
**		a -- address to alias.
**		sendq -- a pointer to the head of the send queue
**			to put the aliases in.
**
**	Returns:
**		none
**
**	Side Effects:
**		Aliases found are expanded.
**
**	Notes:
**		If NoAlias (the "-n" flag) is set, no aliasing is
**			done.
**
**	Deficiencies:
**		It should complain about names that are aliased to
**			nothing.
*/


#ifdef DBM
typedef struct
{
	char	*dptr;
	int	dsize;
} DATUM;
extern DATUM fetch();
#endif DBM

alias(a, sendq)
	register ADDRESS *a;
	ADDRESS **sendq;
{
	register char *p;
	extern char *aliaslookup(), *yellowlookup();

# ifdef DEBUG
	if (tTd(27, 1))
		printf("alias(%s)\n", a->q_paddr);
# endif

	/* don't realias already aliased names */
	if (bitset(QDONTSEND, a->q_flags))
		return;

	CurEnv->e_to = a->q_paddr;

	/*
	**  Look up this name
	*/

	if (NoAlias)
		p = NULL;
	else {
		p = aliaslookup(a->q_user);

		if (p == NULL)
			p = yellowlookup(a);
	}

	if (p == NULL)
		return;

	/*
	**  Match on Alias.
	**	Deliver to the target list.
	*/

# ifdef DEBUG
	if (tTd(27, 1))
		printf("%s (%s, %s) aliased to %s\n",
		    a->q_paddr, a->q_host, a->q_user, p);
# endif
	message(Arpa_Info, "aliased to %s", p);
	AliasLevel++;
	sendtolist(p, a, sendq);
	AliasLevel--;
}
/*
**  ALIASLOOKUP -- look up a name in the alias file.
**
**	Parameters:
**		name -- the name to look up.
**
**	Returns:
**		the value of name.
**		NULL if unknown.
**
**	Side Effects:
**		none.
**
**	Warnings:
**		The return value will be trashed across calls.
*/

char *
aliaslookup(name)
	char *name;
{
# ifdef DBM
	DATUM rhs, lhs;

	/* create a key for fetch */
	lhs.dptr = name;
	lhs.dsize = strlen(name) + 1;
	rhs = fetch(lhs);
	return (rhs.dptr);
# else DBM
	register STAB *s;

	s = stab(name, ST_ALIAS, ST_FIND);
	if (s == NULL)
		return (NULL);
	return (s->s_alias);
# endif DBM
}

char *ypDomain = NULL;

/*
**  YELLOWMATCH -- look up any token in the Network Information Services.
**
**	Parameters:
**		string - string to look up
**		mac - macro to use as name of map
**
**	Returns:
**		True if the value was found in the database
**
**	Side Effects:
**		If token is found, enter into cache.
**		Note the careful copying of the string, converting it
**		to lower case before doing the NIS lookup, and then converting
**		it back to original case in the symbol table.
**
**	Warnings:
**		Will hang forever if no NIS server responds
*/

yellowmatch(string,mac)
    char *string;
    char mac;
  {
  	int insize, outsize;
	register STAB *s;
	char *mapname, *result, *lowered, *macvalue();

	if (mac == 'y')
	  {
	    /*
	     * handle the special host name mapping macro.
	     */
	     struct hostinfo *h, *lookuphost();

	     h = lookuphost(string);
	     errno = 0;
	     return(h->h_exists && (h->h_down == 0 || h->h_errno != ENAMESER));
	  }
	mapname = macvalue(mac,CurEnv);
	if (mapname==NULL) return(FALSE);
	lowered = newstr(string);
	makelower(lowered);
	s = stab(lowered, ST_YP, ST_FIND);
	if (s != NULL) {
		if (bitnset(mac, s->s_value.sv_bitmap2.positive)) {
			free(lowered);
			return(TRUE);
		}
		if (bitnset(mac, s->s_value.sv_bitmap2.negative)) {
			free(lowered);
			return(FALSE);
		}
	}
	else s = stab(lowered, ST_YP, ST_ENTER);
	insize = strlen(lowered);
	if (ypDomain==NULL) {
		  yp_get_default_domain(&ypDomain);
		  if (ypDomain==NULL) return(FALSE);
	}
# ifdef DEBUG
	if (tTd(27, 1))
	    printf("NIS lookup of %s in map %s\n",lowered, mapname);
# endif DEBUG
	if (yp_match(ypDomain,mapname,lowered, insize, &result, &outsize)
	 && yp_match(ypDomain,mapname,lowered, insize+1, &result, &outsize))
	  {
		setbitn(mac, s->s_value.sv_bitmap2.negative);
	  	errno = 0;
		return(FALSE);
	  }
# ifdef DEBUG
	if (tTd(27, 1))
	    printf("NIS found %s as value for %s\n",result,lowered);
# endif DEBUG
	setbitn(mac, s->s_value.sv_bitmap2.positive);
	free(result);
	return(TRUE);
  }

/*
** MAPUSERNAME -- look up a string in the NIS with replacement
**
**	Parameters:
**		map -- name of the NIS map to use
**		buf -- input buffer
**		bufsize -- size of input buffer
**
**	Side Effects:
**		changes buffer to be its value in the map
*/
mapusername(map, buf, bufsize)
    char *map, *buf;
    int bufsize;
  {
  	int insize, outsize;
	char *result, *lowered;

	if (ypDomain==NULL)
		{
		  yp_get_default_domain(&ypDomain);
		  if (ypDomain==NULL) return;
		}
	lowered = newstr(buf);
	makelower(lowered);
	insize = strlen(lowered);
	if (yp_match(ypDomain, map, lowered, insize, &result, &outsize)
	 && yp_match(ypDomain, map, lowered, insize+1, &result, &outsize))
	  {
	  	errno = 0;
		free(lowered);
		return;
	  }
# ifdef DEBUG
	if (tTd(27, 1))
	    printf("NIS found %s as value for %s\n",result,buf);
# endif DEBUG
	free(lowered);
	if (outsize >= bufsize) outsize = bufsize - 1;
	strncpy(buf, result, outsize);
	buf[outsize] = '\0';
  }

/*
**  YELLOWLOOKUP -- look up a name in the NIS.
**
**	Parameters:
**		a -- the address to look up.
**
**	Returns:
**		the value of name.
**		NULL if unknown.
**
**	Side Effects:
**		sets 
**
**	Warnings:
**		The return value will be trashed across calls.
*/

char *
yellowlookup(a)
	register ADDRESS *a;
  {
	char *result;
	int insize, outsize;
	extern char *AliasMap;
	
		/*
		 * if we did not find a local alias, then
		 * try a remote alias through NIS.
		 */
	if (AliasMap==NULL || *AliasMap=='\0') return(NULL);

	if (ypDomain==NULL)
		{
		  yp_get_default_domain(&ypDomain);
		  if (ypDomain == NULL) return(NULL);
# ifdef DEBUG
		  if (tTd(27, 1))
	    		printf("NIS domain is %s\n",ypDomain);
# endif DEBUG
		}
	if (bitset(QWASLOCAL,a->q_flags)) return(NULL);
	insize = strlen(a->q_user);
	if (yp_match(ypDomain,AliasMap,a->q_user, insize, &result, &outsize) &&
	    yp_match(ypDomain,AliasMap,a->q_user, insize+1, &result, &outsize))
	  {
    	    errno = 0;
	    return(NULL);
	  }
  
# ifdef DEBUG
        if (tTd(27, 1))
		printf("%s maps to %s\n",a->q_user, result );
# endif DEBUG
	a->q_flags |= QDOMAIN;
	return(result);
  }
/*
**  INITALIASES -- initialize for aliasing
**
**	Very different depending on whether we are running DBM or not.
**
**	Parameters:
**		aliasfile -- location of aliases.
**		init -- if set and if DBM, initialize the DBM files.
**
**	Returns:
**		none.
**
**	Side Effects:
**		initializes aliases:
**		if DBM:  opens the database.
**		if ~DBM: reads the aliases into the symbol table.
*/

# define DBMMODE	0666

initaliases(aliasfile, init)
	char *aliasfile;
	bool init;
{
#ifdef DBM
	int atcnt;
	bool automatic = FALSE;
	char buf[MAXNAME];
#endif DBM
	time_t modtime;
	struct stat stb;
	static bool initialized = FALSE;

	if (initialized)
		return;
	initialized = TRUE;

	if (aliasfile == NULL || stat(aliasfile, &stb) < 0)
	{
		if (aliasfile != NULL && init)
			syserr("Cannot open %s", aliasfile);
		NoAlias = TRUE;
		errno = 0;
		return;
	}

# ifdef DBM
	/*
	**  Check to see that the alias file is complete.
	**	If not, we will assume that someone died, and it is up
	**	to us to rebuild it.
	*/

	if (!init)
		dbminit(aliasfile);
	atcnt = SafeAlias * 2;
	if (atcnt > 0)
	{
		while (!init && atcnt-- >= 0 && aliaslookup("@") == NULL)
		{
			/*
			**  Reinitialize alias file in case the new
			**  one is mv'ed in instead of cp'ed in.
			**
			**	Only works with new DBM -- old one will
			**	just consume file descriptors forever.
			**	If you have a dbmclose() it can be
			**	added before the sleep(30).
			*/