/*
 * lib/krb5/krb/conv_princ.c
 *
 * Copyright 1992 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 * 
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 * 
 * Build a principal from a V4 specification, or separate a V5
 * principal into name, instance, and realm.
 * 
 * NOTE: This is highly site specific, and is only really necessary
 * for sites who need to convert from V4 to V5.  It is used by both
 * the KDC and the kdb5_convert program.  Since its use is highly
 * specialized, the necesary information is just going to be
 * hard-coded in this file.
 */

#include "k5-int.h"
#include <string.h>
#include <ctype.h>

/* The maximum sizes for V4 aname, realm, sname, and instance +1 */
/* Taken from krb.h */
#define 	ANAME_SZ	40
#define		REALM_SZ	40
#define		SNAME_SZ	40
#define		INST_SZ		40

struct krb_convert {
	char	*v4_str;
	char	*v5_str;
	int	flags;
};

#define DO_REALM_CONVERSION 0x00000001

/*
 * Kadmin doesn't do realm conversion because it's currently
 * kadmin/REALM.NAME.  It should be kadmin/kerberos.master.host, but
 * we'll fix that in the next release.
 */
static struct krb_convert sconv_list[] = {
    {"kadmin",	"kadmin",	0},
    {"rcmd",	"host",		DO_REALM_CONVERSION},
    {"discuss",	"discuss",	DO_REALM_CONVERSION},
    {"rvdsrv",	"rvdsrv",	DO_REALM_CONVERSION},
    {"sample",	"sample",	DO_REALM_CONVERSION},
    {"olc",	"olc",		DO_REALM_CONVERSION},
    {"pop",	"pop",		DO_REALM_CONVERSION},
    {"sis",	"sis",		DO_REALM_CONVERSION},
    {"rfs",	"rfs",		DO_REALM_CONVERSION},
    {0,		0,		0},
};

/*
 * char *strnchr(s, c, n)
 *   char *s;
 *   char c;
 *   int n;
 *
 * returns a pointer to the first occurrence of character c in the
 * string s, or a NULL pointer if c does not occur in in the string;
 * however, at most the first n characters will be considered.
 *
 * This falls in the "should have been in the ANSI C library"
 * category. :-)
 */
static char *strnchr(s, c, n)
   register char *s, c;
   register int n;
{
     if (n < 1) 
	  return 0;
     
     while (n-- && *s) {
	  if (*s == c)
	       return s;
	  s++;
     }
     return 0;
}


/* XXX This calls for a new error code */
#define KRB5_INVALID_PRINCIPAL KRB5_LNAME_BADFORMAT

krb5_error_code
krb5_524_conv_principal(context, princ, name, inst, realm)
    krb5_context context;
    const krb5_principal princ;
    char *name;
    char *inst;
    char *realm;
{
     struct krb_convert *p;
     krb5_data *compo;
     char *c;

     *name = *inst = '\0';
     switch (krb5_princ_size(context, princ)) {
     case 2:
	  /* Check if this principal is listed in the table */
	  compo = krb5_princ_component(context, princ, 0);
	  p = sconv_list;
	  while (p->v4_str) {
	       if (strncmp(p->v5_str, compo->data, compo->length) == 0) {
		    /* It is, so set the new name now, and chop off */
		    /* instance's domain name if requested */
		    strcpy(name, p->v4_str);
		    if (p->flags & DO_REALM_CONVERSION) {
			 compo = krb5_princ_component(context, princ, 1);
			 c = strnchr(compo->data, '.', compo->length);
			 if (!c || (c - compo->data) > INST_SZ - 1)
			      return KRB5_INVALID_PRINCIPAL;
			 strncpy(inst, compo->data, c - compo->data);
			 inst[c - compo->data] = '\0';
		    }
		    break;
	       }
	       p++;
	  }
	  /* If inst isn't set, the service isn't listed in the table, */
	  /* so just copy it. */
	  if (*inst == '\0') {
	       compo = krb5_princ_component(context, princ, 1);
	       if (compo->length >= INST_SZ - 1)
		    return KRB5_INVALID_PRINCIPAL;
	       strncpy(inst, compo->data, compo->length);
	       inst[compo->length] = '\0';
	  }
	  /* fall through */
     case 1:
	  /* name may have been set above; otherwise, just copy it */
	  if (*name == '\0') {
	       compo = krb5_princ_component(context, princ, 0);
	       if (compo->length >= ANAME_SZ)
		    return KRB5_INVALID_PRINCIPAL;
	       strncpy(name, compo->data, compo->length);
	       name[compo->length] = '\0';
	  }
	  break;
     default:
	  return KRB5_INVALID_PRINCIPAL;
     }

     compo = krb5_princ_realm(context, princ);
     if (compo->length > REALM_SZ - 1)
	  return KRB5_INVALID_PRINCIPAL;
     strncpy(realm, compo->data, compo->length);
     realm[compo->length] = '\0';

     return 0;
}

krb5_error_code
krb5_425_conv_principal(context, name, instance, realm, princ)
   krb5_context context;
   const char	*name;
   const char	*instance;
   const char	*realm;
   krb5_principal	*princ;
{
     struct krb_convert *p;
     char buf[256];		/* V4 instances are limited to 40 characters */
     krb5_error_code retval;
     char *domain, *cp;
     char **full_name = 0, **cpp;
     const char *names[5];
     
     if (instance) {
	  if (instance[0] == '\0') {
	       instance = 0;
	       goto not_service;
	  }
	  p = sconv_list;
	  while (1) {
	       if (!p->v4_str)
		    goto not_service;
	       if (!strcmp(p->v4_str, name))
		    break;
	       p++;
	  }
	  name = p->v5_str;
	  if ((p->flags & DO_REALM_CONVERSION) && !strchr(instance, '.')) {
	      names[0] = "realms";
	      names[1] = realm;
	      names[2] = "v4_instance_convert";
	      names[3] = instance;
	      names[4] = 0;
	      retval = profile_get_values(context->profile, names, &full_name);
	      if (retval == 0 && full_name && full_name[0]) {
		  instance = full_name[0];
	      } else {
		  strcpy(buf, instance);
		  retval = krb5_get_realm_domain(context, realm, &domain);
		  if (retval)
		      return retval;
		  if (domain) {
		      for (cp = domain; *cp; cp++)
			  if (isupper(*cp))
			      *cp = tolower(*cp);
		      strcat(buf, ".");
		      strcat(buf, domain);
		      krb5_xfree(domain);
		  }
		  instance = buf;
	      }
	  }
     }
     
not_service:	
     retval = krb5_build_principal(context, princ, strlen(realm), realm, name,
				   instance, 0);
     if (full_name) {
	 for (cpp = full_name; *cpp; cpp++) 
	     krb5_xfree(*cpp);
	 krb5_xfree(full_name);
     }
     return retval;
}
