gnupg/g10/keyring.c

/* keyring.c - keyring file handling
 * Copyright (C) 2001, 2003 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "gpg.h"
#include "util.h"
#include "keyring.h"
#include "packet.h"
#include "keydb.h" 
#include "options.h"
#include "main.h" /*for check_key_signature()*/
#include "i18n.h"

/* off_item is a funny named for an object used to keep track of known
 * keys.  The idea was to use the offset to seek to the known keyblock, but
 * this is not possible if more than one process is using the keyring.
 */
struct off_item {
  struct off_item *next;
  u32 kid[2];
  /*off_t off;*/
};

typedef struct off_item **OffsetHashTable; 


typedef struct keyring_name *KR_NAME;
struct keyring_name {
  struct keyring_name *next;
  int secret;
  DOTLOCK lockhd;
  int is_locked;
  int did_full_scan;
  char fname[1];
};
typedef struct keyring_name const * CONST_KR_NAME;

static KR_NAME kr_names;
static int active_handles;

static OffsetHashTable kr_offtbl;
static int kr_offtbl_ready;


struct keyring_handle {
  CONST_KR_NAME resource;
  int secret;             /* this is for a secret keyring */
  struct {
    CONST_KR_NAME kr;
    iobuf_t iobuf;
    int eof;
    int error;
  } current;
  struct {
    CONST_KR_NAME kr; 
    off_t offset;
    size_t pk_no;
    size_t uid_no;
    unsigned int n_packets; /*used for delete and update*/
  } found;
  struct {
    char *name;
    char *pattern;
  } word_match;
};



static int do_copy (int mode, const char *fname, KBNODE root, int secret,
                    off_t start_offset, unsigned int n_packets );



static struct off_item *
new_offset_item (void)
{
  struct off_item *k;
  
  k = xcalloc (1,sizeof *k);
  return k;
}

#if 0
static void
release_offset_items (struct off_item *k)
{
  struct off_item *k2;

  for (; k; k = k2)
    {
      k2 = k->next;
      xfree (k);
    }
}
#endif

static OffsetHashTable 
new_offset_hash_table (void)
{
  struct off_item **tbl;

  tbl = xcalloc (2048, sizeof *tbl);
  return tbl;
}

#if 0
static void
release_offset_hash_table (OffsetHashTable tbl)
{
  int i;

  if (!tbl)
    return;
  for (i=0; i < 2048; i++)
    release_offset_items (tbl[i]);
  xfree (tbl);
}
#endif

static struct off_item *
lookup_offset_hash_table (OffsetHashTable tbl, u32 *kid)
{
  struct off_item *k;

  for (k = tbl[(kid[1] & 0x07ff)]; k; k = k->next)
    if (k->kid[0] == kid[0] && k->kid[1] == kid[1])
      return k;
  return NULL;
}

static void
update_offset_hash_table (OffsetHashTable tbl, u32 *kid, off_t off)
{
  struct off_item *k;

  for (k = tbl[(kid[1] & 0x07ff)]; k; k = k->next)
    {
      if (k->kid[0] == kid[0] && k->kid[1] == kid[1]) 
        {
          /*k->off = off;*/
          return;
        }
    }

  k = new_offset_item ();
  k->kid[0] = kid[0];
  k->kid[1] = kid[1];
  /*k->off = off;*/
  k->next = tbl[(kid[1] & 0x07ff)];
  tbl[(kid[1] & 0x07ff)] = k;
}

static void
update_offset_hash_table_from_kb (OffsetHashTable tbl, KBNODE node, off_t off)
{
  for (; node; node = node->next)
    {
      if (node->pkt->pkttype == PKT_PUBLIC_KEY
          || node->pkt->pkttype == PKT_PUBLIC_SUBKEY)
        {
          u32 aki[2];
          keyid_from_pk (node->pkt->pkt.public_key, aki);
          update_offset_hash_table (tbl, aki, off);
        }
    }
}

/* 
 * Register a filename for plain keyring files.  ptr is set to a
 * pointer to be used to create a handles etc, or the already-issued
 * pointer if it has already been registered.  The function returns 1
 * if a new keyring was registered.
*/
int
keyring_register_filename (const char *fname, int secret, void **ptr)
{
    KR_NAME kr;

    if (active_handles)
        BUG (); /* We don't allow that */

    for (kr=kr_names; kr; kr = kr->next)
      {
        if ( !compare_filenames (kr->fname, fname) )
	  {
            *ptr=kr;
	    return 0; /* already registered */
	  }
      }

    kr = xmalloc (sizeof *kr + strlen (fname));
    strcpy (kr->fname, fname);
    kr->secret = !!secret;
    kr->lockhd = NULL;
    kr->is_locked = 0;
    kr->did_full_scan = 0;
    /* keep a list of all issued pointers */
    kr->next = kr_names;
    kr_names = kr;

    /* create the offset table the first time a function here is used */
    if (!kr_offtbl)
      kr_offtbl = new_offset_hash_table ();

    *ptr=kr;

    return 1;
}

int
keyring_is_writable (void *token)
{
  KR_NAME r = token;

  return r? !access (r->fname, W_OK) : 0;
}
    


/* Create a new handle for the resource associated with TOKEN.  SECRET
   is just just as a cross-check.
   
   The returned handle must be released using keyring_release (). */
KEYRING_HANDLE
keyring_new (void *token, int secret)
{
  KEYRING_HANDLE hd;
  KR_NAME resource = token;

  assert (resource && !resource->secret == !secret);
  
  hd = xcalloc (1,sizeof *hd);
  hd->resource = resource;
  hd->secret = !!secret;
  active_handles++;
  return hd;
}

void 
keyring_release (KEYRING_HANDLE hd)
{
    if (!hd)
        return;
    assert (active_handles > 0);
    active_handles--;
    xfree (hd->word_match.name);
    xfree (hd->word_match.pattern);
    iobuf_close (hd->current.iobuf);
    xfree (hd);
}


const char *
keyring_get_resource_name (KEYRING_HANDLE hd)
{
    if (!hd || !hd->resource)
      return NULL;
    return hd->resource->fname;
}


/*
 * Lock the keyring with the given handle, or unlok if yes is false.
 * We ignore the handle and lock all registered files.
 */
int 
keyring_lock (KEYRING_HANDLE hd, int yes)
{
    KR_NAME kr;
    int rc = 0;

    if (yes) {
        /* first make sure the lock handles are created */
        for (kr=kr_names; kr; kr = kr->next) {
            if (!keyring_is_writable(kr))
                continue;
            if (!kr->lockhd) {
                kr->lockhd = create_dotlock( kr->fname );
                if (!kr->lockhd) {
                    log_info ("can't allocate lock for `%s'\n", kr->fname );
                    rc = GPG_ERR_GENERAL;
                }
            }
        }
        if (rc)
            return rc;
        
        /* and now set the locks */
        for (kr=kr_names; kr; kr = kr->next) {
            if (!keyring_is_writable(kr))
                continue;
            if (kr->is_locked)
                ;
            else if (make_dotlock (kr->lockhd, -1) ) {
                log_info ("can't lock `%s'\n", kr->fname );
                rc = GPG_ERR_GENERAL;
            }
            else 
                kr->is_locked = 1;
        }
    }

    if (rc || !yes) {
        for (kr=kr_names; kr; kr = kr->next) {
            if (!keyring_is_writable(kr))
                continue;
            if (!kr->is_locked)
                ;
            else if (release_dotlock (kr->lockhd))
                log_info ("can't unlock `%s'\n", kr->fname );
            else 
                kr->is_locked = 0;
        }
    } 

    return rc;
}



/*
 * Return the last found keyring.  Caller must free it.
 * The returned keyblock has the kbode flag bit 0 set for the node with
 * the public key used to locate the keyblock or flag bit 1 set for 
 * the user ID node.
 */
int
keyring_get_keyblock (KEYRING_HANDLE hd, KBNODE *ret_kb)
{
    PACKET *pkt;
    int rc;
    KBNODE keyblock = NULL, node, lastnode;
    iobuf_t a;
    int in_cert = 0;
    int pk_no = 0;
    int uid_no = 0;
    int save_mode;

    if (ret_kb)
        *ret_kb = NULL;

    if (!hd->found.kr)
        return -1; /* no successful search */

    a = iobuf_open (hd->found.kr->fname);
    if (!a) {
	log_error ("can't open `%s'\n", hd->found.kr->fname);
	return GPG_ERR_KEYRING_OPEN;
    }

    if (iobuf_seek (a, hd->found.offset) ) {
        log_error ("can't seek `%s'\n", hd->found.kr->fname);
	iobuf_close(a);
	return GPG_ERR_KEYRING_OPEN;
    }

    pkt = xmalloc (sizeof *pkt);
    init_packet (pkt);
    hd->found.n_packets = 0;;
    lastnode = NULL;
    save_mode = set_packet_list_mode(0);
    while ((rc=parse_packet (a, pkt)) != -1) {
        hd->found.n_packets++;
        if (gpg_err_code (rc) == GPG_ERR_UNKNOWN_PACKET) {
	    free_packet (pkt);
	    init_packet (pkt);
	    continue;
	}
	if (rc) {  
            log_error ("keyring_get_keyblock: read error: %s\n",
                       gpg_strerror (rc) );
            rc = GPG_ERR_INV_KEYRING;
            break;
        }
	if (pkt->pkttype == PKT_COMPRESSED) {
	    log_error ("skipped compressed packet in keyring\n");
	    free_packet(pkt);
	    init_packet(pkt);
	    continue;
        }

        if (in_cert && (pkt->pkttype == PKT_PUBLIC_KEY
                        || pkt->pkttype == PKT_SECRET_KEY)) {
            hd->found.n_packets--; /* fix counter */
            break; /* ready */
        }

        in_cert = 1;
        if (pkt->pkttype == PKT_RING_TRUST) {
            /*(this code is duplicated after the loop)*/
            if ( lastnode 
                 && lastnode->pkt->pkttype == PKT_SIGNATURE
                 && (pkt->pkt.ring_trust->sigcache & 1) ) {
                /* this is a ring trust packet with a checked signature 
                 * status cache following directly a signature paket.
                 * Set the cache status into that signature packet */
                PKT_signature *sig = lastnode->pkt->pkt.signature;
                
                sig->flags.checked = 1;
                sig->flags.valid = !!(pkt->pkt.ring_trust->sigcache & 2);
            }
            /* reset lastnode, so that we set the cache status only from
             * the ring trust packet immediately folling a signature */
            lastnode = NULL;
        }
        else {
            node = lastnode = new_kbnode (pkt);
            if (!keyblock)
                keyblock = node;
            else
                add_kbnode (keyblock, node);

            if ( pkt->pkttype == PKT_PUBLIC_KEY
                 || pkt->pkttype == PKT_PUBLIC_SUBKEY
                 || pkt->pkttype == PKT_SECRET_KEY
                 || pkt->pkttype == PKT_SECRET_SUBKEY) {
                if (++pk_no == hd->found.pk_no)
                    node->flag |= 1;
            }
            else if ( pkt->pkttype == PKT_USER_ID) {
                if (++uid_no == hd->found.uid_no)
                    node->flag |= 2;
            }
        }

        pkt = xmalloc (sizeof *pkt);
        init_packet(pkt);
    }
    set_packet_list_mode(save_mode);

    if (rc == -1 && keyblock) 
	rc = 0; /* got the entire keyblock */

    if (rc || !ret_kb)
	release_kbnode (keyblock);
    else {
        /*(duplicated form the loop body)*/
        if ( pkt && pkt->pkttype == PKT_RING_TRUST
             && lastnode 
             && lastnode->pkt->pkttype == PKT_SIGNATURE
             && (pkt->pkt.ring_trust->sigcache & 1) ) {
            PKT_signature *sig = lastnode->pkt->pkt.signature;
            sig->flags.checked = 1;
            sig->flags.valid = !!(pkt->pkt.ring_trust->sigcache & 2);
        }
	*ret_kb = keyblock;
    }
    free_packet (pkt);
    xfree (pkt);
    iobuf_close(a);

    /* Make sure that future search operations fail immediately when
     * we know that we are working on a invalid keyring 
     */
    if (gpg_err_code (rc) == GPG_ERR_INV_KEYRING)
        hd->current.error = rc;

    return rc;
}

int
keyring_update_keyblock (KEYRING_HANDLE hd, KBNODE kb)
{
    int rc;

    if (!hd->found.kr)
        return -1; /* no successful prior search */

    if (!hd->found.n_packets) {
        /* need to know the number of packets - do a dummy get_keyblock*/
        rc = keyring_get_keyblock (hd, NULL);
        if (rc) {
            log_error ("re-reading keyblock failed: %s\n", gpg_strerror (rc));
            return rc;
        }
        if (!hd->found.n_packets)
            BUG ();
    }

    /* The open iobuf isn't needed anymore and in fact is a problem when
       it comes to renaming the keyring files on some operating systems,
       so close it here */
    iobuf_close(hd->current.iobuf);
    hd->current.iobuf = NULL;

    /* do the update */
    rc = do_copy (3, hd->found.kr->fname, kb, hd->secret,
                  hd->found.offset, hd->found.n_packets );
    if (!rc) {
      if (!hd->secret && kr_offtbl)
        {
          update_offset_hash_table_from_kb (kr_offtbl, kb, 0);
        }
      /* better reset the found info */
      hd->found.kr = NULL;
      hd->found.offset = 0;
    }
    return rc;
}

int
keyring_insert_keyblock (KEYRING_HANDLE hd, KBNODE kb)
{
    int rc;
    const char *fname;

    if (!hd)
        fname = NULL;
    else if (hd->found.kr)
        fname = hd->found.kr->fname;
    else if (hd->current.kr)
        fname = hd->current.kr->fname;
    else 
        fname = hd->resource? hd->resource->fname:NULL;

    if (!fname)
        return GPG_ERR_GENERAL; 

    /* close this one otherwise we will lose the position for
     * a next search.  Fixme: it would be better to adjust the position
     * after the write opertions.
     */
    iobuf_close (hd->current.iobuf);
    hd->current.iobuf = NULL;

    /* do the insert */
    rc = do_copy (1, fname, kb, hd->secret, 0, 0 );
    if (!rc && !hd->secret && kr_offtbl)
      {
        update_offset_hash_table_from_kb (kr_offtbl, kb, 0);
      }
      
    return rc;
}


int
keyring_delete_keyblock (KEYRING_HANDLE hd)
{
    int rc;

    if (!hd->found.kr)
        return -1; /* no successful prior search */

    if (!hd->found.n_packets) {
        /* need to know the number of packets - do a dummy get_keyblock*/
        rc = keyring_get_keyblock (hd, NULL);
        if (rc) {
            log_error ("re-reading keyblock failed: %s\n", gpg_strerror (rc));
            return rc;
        }
        if (!hd->found.n_packets)
            BUG ();
    }

    /* close this one otherwise we will lose the position for
     * a next search.  Fixme: it would be better to adjust the position
     * after the write opertions.
     */
    iobuf_close (hd->current.iobuf);
    hd->current.iobuf = NULL;

    /* do the delete */
    rc = do_copy (2, hd->found.kr->fname, NULL, hd->secret,
                  hd->found.offset, hd->found.n_packets );
    if (!rc) {
        /* better reset the found info */
        hd->found.kr = NULL;
        hd->found.offset = 0;
        /* Delete is a rare operations, so we don't remove the keys
         * from the offset table */
    }
    return rc;
}



/* 
 * Start the next search on this handle right at the beginning
 */
int 
keyring_search_reset (KEYRING_HANDLE hd)
{
    assert (hd);

    hd->current.kr = NULL;
    iobuf_close (hd->current.iobuf);
    hd->current.iobuf = NULL;
    hd->current.eof = 0;
    hd->current.error = 0;
    
    hd->found.kr = NULL;
    hd->found.offset = 0;
    return 0; 
}


static int
prepare_search (KEYRING_HANDLE hd)
{
    if (hd->current.error)  
        return hd->current.error; /* still in error state */

    if (hd->current.kr && !hd->current.eof) {
        if ( !hd->current.iobuf )
            return GPG_ERR_GENERAL; /* position invalid after a modify */
        return 0; /* okay */
    }

    if (!hd->current.kr && hd->current.eof)  
        return -1; /* still EOF */

    if (!hd->current.kr) { /* start search with first keyring */
        hd->current.kr = hd->resource;
        if (!hd->current.kr) {
            hd->current.eof = 1;
            return -1; /* keyring not available */
        }
        assert (!hd->current.iobuf);
    }
    else { /* EOF */
        iobuf_close (hd->current.iobuf); 
        hd->current.iobuf = NULL;
        hd->current.kr = NULL;
        hd->current.eof = 1;
        return -1;
    }

    hd->current.eof = 0;
    hd->current.iobuf = iobuf_open (hd->current.kr->fname);
    if (!hd->current.iobuf) {
        hd->current.error = gpg_error_from_errno (errno);
        log_error ("can't open `%s'\n", hd->current.kr->fname );
        return hd->current.error;
    }

    return 0;
}


/* A map of the all characters valid used for word_match()
 * Valid characters are in in this table converted to uppercase.
 * because the upper 128 bytes have special meaning, we assume
 * that they are all valid.
 * Note: We must use numerical values here in case that this program
 * will be converted to those little blue HAL9000s with their strange
 * EBCDIC character set (user ids are UTF-8).
 * wk 2000-04-13: Hmmm, does this really make sense, given the fact that
 * we can run gpg now on a S/390 running GNU/Linux, where the code
 * translation is done by the device drivers?
 */
static const byte word_match_chars[256] = {
  /* 00 */  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 08 */  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 10 */  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 18 */  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 20 */  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 28 */  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 30 */  0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
  /* 38 */  0x38, 0x39, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 40 */  0x00, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
  /* 48 */  0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
  /* 50 */  0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
  /* 58 */  0x58, 0x59, 0x5a, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 60 */  0x00, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
  /* 68 */  0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
  /* 70 */  0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
  /* 78 */  0x58, 0x59, 0x5a, 0x00, 0x00, 0x00, 0x00, 0x00,
  /* 80 */  0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
  /* 88 */  0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
  /* 90 */  0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
  /* 98 */  0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
  /* a0 */  0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
  /* a8 */  0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
  /* b0 */  0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
  /* b8 */  0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
  /* c0 */  0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
  /* c8 */  0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
  /* d0 */  0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
  /* d8 */  0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
  /* e0 */  0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
  /* e8 */  0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
  /* f0 */  0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
  /* f8 */  0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
};

/****************
 * Do a word match (original user id starts with a '+').
 * The pattern is already tokenized to a more suitable format:
 * There are only the real words in it delimited by one space
 * and all converted to uppercase.
 *
 * Returns: 0 if all words match.
 *
 * Note: This algorithm is a straightforward one and not very
 *	 fast.	It works for UTF-8 strings.  The uidlen should
 *	 be removed but due to the fact that old versions of
 *	 pgp don't use UTF-8 we still use the length; this should
 *	 be fixed in parse-packet (and replace \0 by some special
 *	 UTF-8 encoding)
 */
static int
word_match( const byte *uid, size_t uidlen, const byte *pattern )
{
    size_t wlen, n;
    const byte *p;
    const byte *s;

    for( s=pattern; *s; ) {
	do {
	    /* skip leading delimiters */
	    while( uidlen && !word_match_chars[*uid] )
		uid++, uidlen--;
	    /* get length of the word */
	    n = uidlen; p = uid;
	    while( n && word_match_chars[*p] )
		p++, n--;
	    wlen = p - uid;
	    /* and compare against the current word from pattern */
	    for(n=0, p=uid; n < wlen && s[n] != ' ' && s[n] ; n++, p++ ) {
		if( word_match_chars[*p] != s[n] )
		    break;
	    }
	    if( n == wlen && (s[n] == ' ' || !s[n]) )
		break; /* found */
	    uid += wlen;
	    uidlen -= wlen;
	} while( uidlen );
	if( !uidlen )
	    return -1; /* not found */

	/* advance to next word in pattern */
	for(; *s != ' ' && *s ; s++ )
	    ;
	if( *s )
	    s++ ;
    }
    return 0; /* found */
}

/****************
 * prepare word word_match; that is parse the name and
 * build the pattern.
 * caller has to free the returned pattern
 */
static char*
prepare_word_match (const byte *name)
{
    byte *pattern, *p;
    int c;

    /* the original length is always enough for the pattern */
    p = pattern = xmalloc (strlen(name)+1);
    do {
	/* skip leading delimiters */
	while( *name && !word_match_chars[*name] )
	    name++;
	/* copy as long as we don't have a delimiter and convert
	 * to uppercase.
	 * fixme: how can we handle utf8 uppercasing */
	for( ; *name &&  (c=word_match_chars[*name]); name++ )
	    *p++ = c;
	*p++ = ' '; /* append pattern delimiter */
    } while( *name );
    p[-1] = 0; /* replace last pattern delimiter by EOS */

    return pattern;
}




static int
compare_name (int mode, const char *name, const char *uid, size_t uidlen)
{
    int i;
    const char *s, *se;

    if (mode == KEYDB_SEARCH_MODE_EXACT) { 
	for (i=0; name[i] && uidlen; i++, uidlen--)
	    if (uid[i] != name[i])
		break;
	if (!uidlen && !name[i])
	    return 0; /* found */
    }
    else if (mode == KEYDB_SEARCH_MODE_SUBSTR) {
	if (ascii_memistr( uid, uidlen, name ))
	    return 0;
    }
    else if (   mode == KEYDB_SEARCH_MODE_MAIL 
             || mode == KEYDB_SEARCH_MODE_MAILSUB
             || mode == KEYDB_SEARCH_MODE_MAILEND) {
	for (i=0, s= uid; i < uidlen && *s != '<'; s++, i++)
	    ;
	if (i < uidlen)  {
	    /* skip opening delim and one char and look for the closing one*/
	    s++; i++;
	    for (se=s+1, i++; i < uidlen && *se != '>'; se++, i++)
		;
	    if (i < uidlen) {
		i = se - s;
		if (mode == KEYDB_SEARCH_MODE_MAIL) { 
		    if( strlen(name)-2 == i
                        && !ascii_memcasecmp( s, name+1, i) )
			return 0;
		}
		else if (mode == KEYDB_SEARCH_MODE_MAILSUB) {
		    if( ascii_memistr( s, i, name ) )
			return 0;
		}
		else { /* email from end */
		    /* nyi */
		}
	    }
	}
    }
    else if (mode == KEYDB_SEARCH_MODE_WORDS)
	return word_match (uid, uidlen, name);
    else
	BUG();

    return -1; /* not found */
}


/* 
 * Search through the keyring(s), starting at the current position,
 * for a keyblock which contains one of the keys described in the DESC array.
 */
int 
keyring_search (KEYRING_HANDLE hd, KEYDB_SEARCH_DESC *desc,
		size_t ndesc, size_t *descindex)
{
  int rc;
  PACKET pkt;
  int save_mode;
  off_t offset, main_offset;
  size_t n;
  int need_uid, need_words, need_keyid, need_fpr, any_skip;
  int pk_no, uid_no;
  int initial_skip;
  int use_offtbl;
  PKT_user_id *uid = NULL;
  PKT_public_key *pk = NULL;
  PKT_secret_key *sk = NULL;
  u32 aki[2];

  /* figure out what information we need */
  need_uid = need_words = need_keyid = need_fpr = any_skip = 0;
  for (n=0; n < ndesc; n++) 
    {
      switch (desc[n].mode) 
        {
        case KEYDB_SEARCH_MODE_EXACT: 
        case KEYDB_SEARCH_MODE_SUBSTR:
        case KEYDB_SEARCH_MODE_MAIL:
        case KEYDB_SEARCH_MODE_MAILSUB:
        case KEYDB_SEARCH_MODE_MAILEND:
          need_uid = 1;
          break;
        case KEYDB_SEARCH_MODE_WORDS: 
          need_uid = 1;
          need_words = 1;
          break;
        case KEYDB_SEARCH_MODE_SHORT_KID: 
        case KEYDB_SEARCH_MODE_LONG_KID:
          need_keyid = 1;
          break;
        case KEYDB_SEARCH_MODE_FPR16: 
        case KEYDB_SEARCH_MODE_FPR20:
        case KEYDB_SEARCH_MODE_FPR: 
          need_fpr = 1;
          break;
        case KEYDB_SEARCH_MODE_FIRST:
          /* always restart the search in this mode */
          keyring_search_reset (hd);
          break;
        default: break;
	}
      if (desc[n].skipfnc) 
        {
          any_skip = 1;
          need_keyid = 1;
        }
    }

  rc = prepare_search (hd);
  if (rc)
    return rc;

  use_offtbl = !hd->secret && kr_offtbl;
  if (!use_offtbl)
    ;
  else if (!kr_offtbl_ready)
    need_keyid = 1;
  else if (ndesc == 1 && desc[0].mode == KEYDB_SEARCH_MODE_LONG_KID)
    {
      struct off_item *oi;
            
      oi = lookup_offset_hash_table (kr_offtbl, desc[0].u.kid);
      if (!oi)
        { /* We know that we don't have this key */
          hd->found.kr = NULL;
          hd->current.eof = 1;
          return -1;
        }
      /* We could now create a positive search status and return.
       * However the problem is that another instance of gpg may 
       * have changed the keyring so that the offsets are not valid
       * anymore - therefore we don't do it 
       */
    }

  if (need_words)
    {
      const char *name = NULL;

      log_debug ("word search mode does not yet work\n");
      /* FIXME: here is a long standing bug in our function and in addition we
         just use the first search description */
      for (n=0; n < ndesc && !name; n++) 
        {
          if (desc[n].mode == KEYDB_SEARCH_MODE_WORDS) 
            name = desc[n].u.name;
        }
      assert (name);
      if ( !hd->word_match.name || strcmp (hd->word_match.name, name) ) 
        {
          /* name changed */
          xfree (hd->word_match.name);
          xfree (hd->word_match.pattern);
          hd->word_match.name = xstrdup (name);
          hd->word_match.pattern = prepare_word_match (name);
        }
      name = hd->word_match.pattern;
    }

  init_packet(&pkt);
  save_mode = set_packet_list_mode(0);

  hd->found.kr = NULL;
  main_offset = 0;
  pk_no = uid_no = 0;
  initial_skip = 1; /* skip until we see the start of a keyblock */
  while (!(rc=search_packet (hd->current.iobuf, &pkt, &offset, need_uid))) 
    {
      byte afp[MAX_FINGERPRINT_LEN];
      size_t an;

      if (pkt.pkttype == PKT_PUBLIC_KEY  || pkt.pkttype == PKT_SECRET_KEY) 
        {
          main_offset = offset;
          pk_no = uid_no = 0;
          initial_skip = 0;
        }
      if (initial_skip) 
        {
          free_packet (&pkt);
          continue;
        }
	
      pk = NULL;
      sk = NULL;
      uid = NULL;
      if (   pkt.pkttype == PKT_PUBLIC_KEY
             || pkt.pkttype == PKT_PUBLIC_SUBKEY)
        {
          pk = pkt.pkt.public_key;
          ++pk_no;

          if (need_fpr) {
            fingerprint_from_pk (pk, afp, &an);
            while (an < 20) /* fill up to 20 bytes */
              afp[an++] = 0;
          }
          if (need_keyid)
            keyid_from_pk (pk, aki);

          if (use_offtbl && !kr_offtbl_ready)
            update_offset_hash_table (kr_offtbl, aki, main_offset);
        }
      else if (pkt.pkttype == PKT_USER_ID) 
        {
          uid = pkt.pkt.user_id;
          ++uid_no;
        }
      else if (    pkt.pkttype == PKT_SECRET_KEY
                   || pkt.pkttype == PKT_SECRET_SUBKEY) 
        {
          sk = pkt.pkt.secret_key;
          ++pk_no;

          if (need_fpr) {
            fingerprint_from_sk (sk, afp, &an);
            while (an < 20) /* fill up to 20 bytes */
              afp[an++] = 0;
          }
          if (need_keyid)
            keyid_from_sk (sk, aki);
            
        }

      for (n=0; n < ndesc; n++) 
        {
          switch (desc[n].mode) {
          case KEYDB_SEARCH_MODE_NONE: 
            BUG ();
            break;
          case KEYDB_SEARCH_MODE_EXACT: 
          case KEYDB_SEARCH_MODE_SUBSTR:
          case KEYDB_SEARCH_MODE_MAIL:
          case KEYDB_SEARCH_MODE_MAILSUB:
          case KEYDB_SEARCH_MODE_MAILEND:
          case KEYDB_SEARCH_MODE_WORDS: 
            if ( uid && !compare_name (desc[n].mode,
                                       desc[n].u.name,
                                       uid->name, uid->len)) 
              goto found;
            break;
                
          case KEYDB_SEARCH_MODE_SHORT_KID: 
            if ((pk||sk) && desc[n].u.kid[1] == aki[1])
              goto found;
            break;
          case KEYDB_SEARCH_MODE_LONG_KID:
            if ((pk||sk) && desc[n].u.kid[0] == aki[0]
                && desc[n].u.kid[1] == aki[1])
              goto found;
            break;
          case KEYDB_SEARCH_MODE_FPR16:
            if ((pk||sk) && !memcmp (desc[n].u.fpr, afp, 16))
              goto found;
            break;
          case KEYDB_SEARCH_MODE_FPR20:
          case KEYDB_SEARCH_MODE_FPR: 
            if ((pk||sk) && !memcmp (desc[n].u.fpr, afp, 20))
              goto found;
            break;
          case KEYDB_SEARCH_MODE_FIRST: 
            if (pk||sk)
              goto found;
            break;
          case KEYDB_SEARCH_MODE_NEXT: 
            if (pk||sk)
              goto found;
            break;
          default: 
            rc = GPG_ERR_INV_ARG;
            goto found;
          }
	}
      free_packet (&pkt);
      continue;
    found:
      /* Record which desc we matched on.  Note this value is only
	 meaningful if this function returns with no errors. */
      if(descindex)
	*descindex=n;
      for (n=any_skip?0:ndesc; n < ndesc; n++) 
        {
          if (desc[n].skipfnc
              && desc[n].skipfnc (desc[n].skipfncvalue, aki))
            break;
        }
      if (n == ndesc)
        goto real_found;
      free_packet (&pkt);
    }
 real_found:
  if (!rc)
    {
      hd->found.offset = main_offset;
      hd->found.kr = hd->current.kr;
      hd->found.pk_no = (pk||sk)? pk_no : 0;
      hd->found.uid_no = uid? uid_no : 0;
    }
  else if (rc == -1)
    {
      hd->current.eof = 1;
      /* if we scanned all keyrings, we are sure that
       * all known key IDs are in our offtbl, mark that. */
      if (use_offtbl && !kr_offtbl_ready)
        {
          KR_NAME kr;
          
          /* First set the did_full_scan flag for this keyring (ignore
             secret keyrings) */
          for (kr=kr_names; kr; kr = kr->next)
            {
              if (!kr->secret && hd->resource == kr) 
                {
                  kr->did_full_scan = 1;
                  break;
                }
            }
          /* Then check whether all flags are set and if so, mark the
             offtbl ready */
          for (kr=kr_names; kr; kr = kr->next)
            {
              if (!kr->secret && !kr->did_full_scan) 
                break;
            }
          if (!kr)
            kr_offtbl_ready = 1;
        }
    }
  else 
    hd->current.error = rc;

  free_packet(&pkt);
  set_packet_list_mode(save_mode);
  return rc;
}


static int
create_tmp_file (const char *template,
                 char **r_bakfname, char **r_tmpfname, iobuf_t *r_fp)
{  
  char *bakfname, *tmpfname;
  mode_t oldmask;

  *r_bakfname = NULL;
  *r_tmpfname = NULL;

# ifdef USE_ONLY_8DOT3
  /* Here is another Windoze bug?:
   * you cant rename("pubring.gpg.tmp", "pubring.gpg");
   * but	rename("pubring.gpg.tmp", "pubring.aaa");
   * works.  So we replace .gpg by .bak or .tmp
   */
  if (strlen (template) > 4
      && !strcmp (template+strlen(template)-4, EXTSEP_S "gpg") )
    {
      bakfname = xmalloc (strlen (template) + 1);
      strcpy (bakfname, template);
      strcpy (bakfname+strlen(template)-4, EXTSEP_S "bak");

      tmpfname = xmalloc (strlen( template ) + 1 );
      strcpy (tmpfname,template);
      strcpy (tmpfname+strlen(template)-4, EXTSEP_S "tmp");
    }
    else 
      { /* file does not end with gpg; hmmm */
	bakfname = xmalloc (strlen( template ) + 5);
	strcpy (stpcpy(bakfname, template), EXTSEP_S "bak");

	tmpfname = xmalloc (strlen( template ) + 5);
	strcpy (stpcpy(tmpfname, template), EXTSEP_S "tmp");
    }
# else /* Posix file names */
    bakfname = xmalloc (strlen( template ) + 2);
    strcpy (stpcpy (bakfname,template),"~");

    tmpfname = xmalloc (strlen( template ) + 5);
    strcpy (stpcpy(tmpfname,template), EXTSEP_S "tmp");
# endif /* Posix filename */

    /* Create the temp file with limited access */
    oldmask=umask(077);
    *r_fp = iobuf_create (tmpfname);
    umask(oldmask);
    if (!*r_fp) {
        int tmperr = gpg_error_from_errno (errno);
	log_error ("can't create `%s': %s\n", tmpfname, strerror(errno) );
        xfree (tmpfname);
        xfree (bakfname);
	return tmperr;
    }
    
    *r_bakfname = bakfname;
    *r_tmpfname = tmpfname;
    return 0;
}


static int
rename_tmp_file (const char *bakfname, const char *tmpfname,
                 const char *fname, int secret )
{
  int rc=0;

  /* invalidate close caches*/
  iobuf_ioctl (NULL, 2, 0, (char*)tmpfname );
  iobuf_ioctl (NULL, 2, 0, (char*)bakfname );
  iobuf_ioctl (NULL, 2, 0, (char*)fname );

  /* first make a backup file except for secret keyrings */
  if (!secret)
    { 
#if defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__)
      remove (bakfname);
#endif
      if (rename (fname, bakfname) )
        {
          int tmperr = gpg_error_from_errno (errno);
          log_error ("renaming `%s' to `%s' failed: %s\n",
                     fname, bakfname, strerror(errno) );
          return tmperr;
	}
    }
  
  /* then rename the file */
#if defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__)
  remove( fname );
#endif
  if (rename (tmpfname, fname) )
    {
      rc = gpg_error_from_errno (errno);
      log_error ("renaming `%s' to `%s' failed: %s\n",
                 tmpfname, fname, strerror(errno) );
      if (secret)
        {
          log_info(_("WARNING: 2 files with confidential"
                     " information exists.\n"));
          log_info(_("%s is the unchanged one\n"), fname );
          log_info(_("%s is the new one\n"), tmpfname );
          log_info(_("Please fix this possible security flaw\n"));
	}
      return rc;
    }

  /* Now make sure the file has the same permissions as the original */

#ifndef HAVE_DOSISH_SYSTEM
  {
    struct stat statbuf;

    statbuf.st_mode=S_IRUSR | S_IWUSR;

    if(((secret && !opt.preserve_permissions) ||
	(stat(bakfname,&statbuf)==0)) &&
       (chmod(fname,statbuf.st_mode)==0))
      ;
    else
      log_error("WARNING: unable to restore permissions to `%s': %s",
		fname,strerror(errno));
  }
#endif

  return 0;
}


static int
write_keyblock (iobuf_t fp, KBNODE keyblock)
{
  KBNODE kbctx = NULL, node;
  int rc;
  
  while ( (node = walk_kbnode (keyblock, &kbctx, 0)) ) 
    {
      if (node->pkt->pkttype == PKT_RING_TRUST) 
        continue; /* we write it later on our own */

      if ( (rc = build_packet (fp, node->pkt) ))
        {
          log_error ("build_packet(%d) failed: %s\n",
                     node->pkt->pkttype, gpg_strerror (rc) );
          return rc;
        }
      if (node->pkt->pkttype == PKT_SIGNATURE) 
        { /* always write a signature cache packet */
          PKT_signature *sig = node->pkt->pkt.signature;
          unsigned int cacheval = 0;
          
          if (sig->flags.checked) 
            {
              cacheval |= 1;
              if (sig->flags.valid)
                cacheval |= 2;
            }
          iobuf_put (fp, 0xb0); /* old style packet 12, 1 byte len*/
          iobuf_put (fp, 2);    /* 2 bytes */
          iobuf_put (fp, 0);    /* unused */
          if (iobuf_put (fp, cacheval)) {
            int tmperr = gpg_error_from_errno (errno);
            log_error ("writing sigcache packet failed\n");
            return tmperr;
          }
        }
    }
  return 0;
}

/* 
 * Walk over all public keyrings, check the signatures and replace the
 * keyring with a new one where the signature cache is then updated.
 * This is only done for the public keyrings.
 */
int
keyring_rebuild_cache (void *token)
{
  KEYRING_HANDLE hd;
  KEYDB_SEARCH_DESC desc;
  KBNODE keyblock = NULL, node;
  const char *lastresname = NULL, *resname;
  iobuf_t tmpfp = NULL;
  char *tmpfilename = NULL;
  char *bakfilename = NULL;
  int rc;
  ulong count = 0, sigcount = 0;

  hd = keyring_new (token, 0);
  memset (&desc, 0, sizeof desc);
  desc.mode = KEYDB_SEARCH_MODE_FIRST;

  rc=keyring_lock (hd, 1);
  if(rc)
    goto leave;

  while ( !(rc = keyring_search (hd, &desc, 1, NULL)) )
    {
      desc.mode = KEYDB_SEARCH_MODE_NEXT;
      resname = keyring_get_resource_name (hd);
      if (lastresname != resname )
        { /* we have switched to a new keyring - commit changes */
          if (tmpfp)
            {
              if (iobuf_close (tmpfp))
                {
                  rc = gpg_error_from_errno (errno);
                  log_error ("error closing `%s': %s\n",
                             tmpfilename, strerror (errno));
                  goto leave;
                }
              /* because we have switched resources, we can be sure that
               * the original file is closed */
              tmpfp = NULL;
            }
          rc = lastresname? rename_tmp_file (bakfilename, tmpfilename, 
                                             lastresname, 0) : 0;
          xfree (tmpfilename);  tmpfilename = NULL;
          xfree (bakfilename);  bakfilename = NULL;
          if (rc)
            goto leave;
          lastresname = resname;
          if (!opt.quiet)
            log_info (_("checking keyring `%s'\n"), resname);
          rc = create_tmp_file (resname, &bakfilename, &tmpfilename, &tmpfp);
          if (rc)
            goto leave;
        }
      
      release_kbnode (keyblock);
      rc = keyring_get_keyblock (hd, &keyblock);
      if (rc) 
        {
          log_error ("keyring_get_keyblock failed: %s\n", gpg_strerror (rc));
          goto leave;
        }
      assert (keyblock->pkt->pkttype == PKT_PUBLIC_KEY);

      /* check all signature to set the signature's cache flags */
      for (node=keyblock; node; node=node->next)
        {
          if (node->pkt->pkttype == PKT_SIGNATURE)
            {
	      /* Note that this doesn't cache the result of a
		 revocation issued by a designated revoker.  This is
		 because the pk in question does not carry the revkeys
		 as we haven't merged the key and selfsigs.  It is
		 questionable whether this matters very much since
		 there are very very few designated revoker revocation
		 packets out there. */
              check_key_signature (keyblock, node, NULL);
              sigcount++;
            }
        }
      
      /* write the keyblock to the temporary file */
      rc = write_keyblock (tmpfp, keyblock);
      if (rc)
        goto leave;

      if ( !(++count % 50) && !opt.quiet)
        log_info(_("%lu keys checked so far (%lu signatures)\n"),
                 count, sigcount );

    } /* end main loop */ 
  if (rc == -1)
    rc = 0;
  if (rc) 
    {
      log_error ("keyring_search failed: %s\n", gpg_strerror (rc));
      goto leave;
    }
  log_info(_("%lu keys checked (%lu signatures)\n"), count, sigcount );
  if (tmpfp)
    {
      if (iobuf_close (tmpfp))
        {
          rc = gpg_error_from_errno (errno);
          log_error ("error closing `%s': %s\n",
                     tmpfilename, strerror (errno));
          goto leave;
        }
      /* because we have switched resources, we can be sure that
       * the original file is closed */
      tmpfp = NULL;
    }
  rc = lastresname? rename_tmp_file (bakfilename, tmpfilename,
                                     lastresname, 0) : 0;
  xfree (tmpfilename);  tmpfilename = NULL;
  xfree (bakfilename);  bakfilename = NULL;

 leave:
  if (tmpfp)
    iobuf_cancel (tmpfp);
  xfree (tmpfilename);  
  xfree (bakfilename);  
  release_kbnode (keyblock);
  keyring_lock (hd, 0);
  keyring_release (hd);
  return rc;
}


/****************
 * Perform insert/delete/update operation.
 * mode 1 = insert
 *	2 = delete
 *	3 = update
 */
static int
do_copy (int mode, const char *fname, KBNODE root, int secret,
         off_t start_offset, unsigned int n_packets )
{
    iobuf_t fp, newfp;
    int rc=0;
    char *bakfname = NULL;
    char *tmpfname = NULL;

    /* Open the source file. Because we do a rname, we have to check the 
       permissions of the file */
    if (access (fname, W_OK))
      return gpg_error_from_errno (errno);


    fp = iobuf_open (fname);
    if (mode == 1 && !fp && errno == ENOENT) { 
	/* insert mode but file does not exist: create a new file */
	KBNODE kbctx, node;
	mode_t oldmask;

	oldmask=umask(077);
	newfp = iobuf_create (fname);
	umask(oldmask);
	if( !newfp ) {
            int tmperr = gpg_error_from_errno (errno);
	    log_error (_("%s: can't create: %s\n"),
                       fname, strerror(errno));
	    return tmperr;
	}
	if( !opt.quiet )
	    log_info(_("%s: keyring created\n"), fname );

	kbctx=NULL;
	while ( (node = walk_kbnode( root, &kbctx, 0 )) ) {
	    if( (rc = build_packet( newfp, node->pkt )) ) {
		log_error("build_packet(%d) failed: %s\n",
			    node->pkt->pkttype, gpg_strerror (rc) );
		iobuf_cancel(newfp);
		return rc;
	    }
	}
	if (iobuf_close(newfp)) {
            int tmperr = gpg_error_from_errno (errno);
	    log_error ("%s: close failed: %s\n", fname, strerror(errno));
	    return tmperr;
	}
	return 0; /* ready */
    }

    if( !fp ) {
        rc = gpg_error_from_errno (errno);
	log_error ("%s: can't open: %s\n", fname, strerror(errno) );
	goto leave;
    }

    /* create the new file */
    rc = create_tmp_file (fname, &bakfname, &tmpfname, &newfp);
    if (rc) {
	iobuf_close(fp);
	goto leave;
    }
    if( mode == 1 ) { /* insert */
	/* copy everything to the new file */
	rc = copy_all_packets (fp, newfp);
	if( rc != -1 ) {
	    log_error("%s: copy to `%s' failed: %s\n",
		      fname, tmpfname, gpg_strerror (rc) );
	    iobuf_close(fp);
	    iobuf_cancel(newfp);
	    goto leave;
	}
	rc = 0;
    }

    if( mode == 2 || mode == 3 ) { /* delete or update */
	/* copy first part to the new file */
	rc = copy_some_packets( fp, newfp, start_offset );
	if( rc ) { /* should never get EOF here */
	    log_error ("%s: copy to `%s' failed: %s\n",
                       fname, tmpfname, gpg_strerror (rc) );
	    iobuf_close(fp);
	    iobuf_cancel(newfp);
	    goto leave;
	}
	/* skip this keyblock */
	assert( n_packets );
	rc = skip_some_packets( fp, n_packets );
	if( rc ) {
	    log_error("%s: skipping %u packets failed: %s\n",
			    fname, n_packets, gpg_strerror (rc));
	    iobuf_close(fp);
	    iobuf_cancel(newfp);
	    goto leave;
	}
    }

    if( mode == 1 || mode == 3 ) { /* insert or update */
        rc = write_keyblock (newfp, root);
        if (rc) {
          iobuf_close(fp);
          iobuf_cancel(newfp);
          goto leave;
        }
    }

    if( mode == 2 || mode == 3 ) { /* delete or update */
	/* copy the rest */
	rc = copy_all_packets( fp, newfp );
	if( rc != -1 ) {
	    log_error("%s: copy to `%s' failed: %s\n",
		      fname, tmpfname, gpg_strerror (rc) );
	    iobuf_close(fp);
	    iobuf_cancel(newfp);
	    goto leave;
	}
	rc = 0;
    }

    /* close both files */
    if( iobuf_close(fp) ) {
        rc = gpg_error_from_errno (errno);
	log_error("%s: close failed: %s\n", fname, strerror(errno) );
	goto leave;
    }
    if( iobuf_close(newfp) ) {
        rc = gpg_error_from_errno (errno);
	log_error("%s: close failed: %s\n", tmpfname, strerror(errno) );
	goto leave;
    }

    rc = rename_tmp_file (bakfname, tmpfname, fname, secret);

  leave:
    xfree (bakfname);
    xfree (tmpfname);
    return rc;
}