gnupg/g10/keydb.h

/* keydb.h - Key database
 * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
 *               2006, 2010 Free Software Foundation, Inc.
 * Copyright (C) 2015 g10 Code GmbH
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#ifndef G10_KEYDB_H
#define G10_KEYDB_H

#include <assuan.h>

#include "types.h"
#include "util.h"
#include "packet.h"

/* What qualifies as a certification (rather than a signature?) */
#define IS_CERT(s)       (IS_KEY_SIG(s) || IS_UID_SIG(s) || IS_SUBKEY_SIG(s) \
                         || IS_KEY_REV(s) || IS_UID_REV(s) || IS_SUBKEY_REV(s))
#define IS_SIG(s)        (!IS_CERT(s))
#define IS_KEY_SIG(s)    ((s)->sig_class == 0x1f)
#define IS_UID_SIG(s)    (((s)->sig_class & ~3) == 0x10)
#define IS_SUBKEY_SIG(s) ((s)->sig_class == 0x18)
#define IS_KEY_REV(s)    ((s)->sig_class == 0x20)
#define IS_UID_REV(s)    ((s)->sig_class == 0x30)
#define IS_SUBKEY_REV(s) ((s)->sig_class == 0x28)

struct getkey_ctx_s;
typedef struct getkey_ctx_s *GETKEY_CTX;
typedef struct getkey_ctx_s *getkey_ctx_t;

/****************
 * A Keyblock is all packets which form an entire certificate;
 * i.e. the public key, certificate, trust packets, user ids,
 * signatures, and subkey.
 *
 * This structure is also used to bind arbitrary packets together.
 */

struct kbnode_struct {
    KBNODE next;
    PACKET *pkt;
    int flag;
    int private_flag;
    ulong recno;  /* used while updating the trustdb */
};

#define is_deleted_kbnode(a)  ((a)->private_flag & 1)
#define is_cloned_kbnode(a)   ((a)->private_flag & 2)


enum resource_type {
    rt_UNKNOWN = 0,
    rt_RING = 1
};


/****************
 * A data structure to hold information about the external position
 * of a keyblock.
 */
struct keyblock_pos_struct {
    int   resno;     /* resource number */
    enum resource_type rt;
    off_t offset;    /* position information */
    unsigned count;  /* length of the keyblock in packets */
    iobuf_t  fp;     /* Used by enum_keyblocks. */
    int secret;      /* working on a secret keyring */
    PACKET *pkt;     /* ditto */
    int valid;
};
typedef struct keyblock_pos_struct KBPOS;

/* Structure to hold a couple of public key certificates. */
typedef struct pk_list *PK_LIST;  /* Deprecated. */
typedef struct pk_list *pk_list_t;
struct pk_list
{
  PK_LIST next;
  PKT_public_key *pk;
  int flags; /* flag bit 1==throw_keyid */
};

/* Structure to hold a list of secret key certificates.  */
typedef struct sk_list *SK_LIST;
struct sk_list
{
  SK_LIST next;
  PKT_public_key *pk;
  int mark; /* not used */
};

/* structure to collect all information which can be used to
 * identify a public key */
typedef struct pubkey_find_info *PUBKEY_FIND_INFO;
struct pubkey_find_info {
    u32  keyid[2];
    unsigned nbits;
    byte pubkey_algo;
    byte fingerprint[MAX_FINGERPRINT_LEN];
    char userid[1];
};


typedef struct keydb_handle *KEYDB_HANDLE;


/* Helper type for preference fucntions. */
union pref_hint
{
  int digest_length;
};


/*-- keydb.c --*/

#define KEYDB_RESOURCE_FLAG_PRIMARY  2  /* The primary resource.  */
#define KEYDB_RESOURCE_FLAG_DEFAULT  4  /* The default one.  */
#define KEYDB_RESOURCE_FLAG_READONLY 8  /* Open in read only mode.  */
#define KEYDB_RESOURCE_FLAG_GPGVDEF 16  /* Default file for gpgv.  */

/* Register a resource (keyring or keybox).  The first keyring or
   keybox that is added using this function is created if it does not
   already exist and the KEYDB_RESOURCE_FLAG_READONLY is not set.

   FLAGS are a combination of the KEYDB_RESOURCE_FLAG_* constants.

   URL must have the following form:

     gnupg-ring:filename  = plain keyring
     gnupg-kbx:filename   = keybox file
     filename             = check file's type (create as a plain keyring)

   Note: on systems with drive letters (Windows) invalid URLs (i.e.,
   those with an unrecognized part before the ':' such as "c:\...")
   will silently be treated as bare filenames.  On other systems, such
   URLs will cause this function to return GPG_ERR_GENERAL.

   If KEYDB_RESOURCE_FLAG_DEFAULT is set, the resource is a keyring
   and the file ends in ".gpg", then this function also checks if a
   file with the same name, but the extension ".kbx" exists, is a
   keybox and the OpenPGP flag is set.  If so, this function opens
   that resource instead.

   If the file is not found, KEYDB_RESOURCE_FLAG_GPGVDEF is set and
   the URL ends in ".kbx", then this function will try opening the
   same URL, but with the extension ".gpg".  If that file is a keybox
   with the OpenPGP flag set or it is a keyring, then we use that
   instead.

   If the file is not found, KEYDB_RESOURCE_FLAG_DEFAULT is set, the
   file should be created and the file's extension is ".gpg" then we
   replace the extension with ".kbx".


   If the KEYDB_RESOURCE_FLAG_PRIMARY is set and the resource is a
   keyring (not a keybox), then this resource is considered the
   primary resource.  This is used by keydb_locate_writable().  If
   another primary keyring is set, then that keyring is considered the
   primary.

   If KEYDB_RESOURCE_FLAG_READONLY is set and the resource is a
   keyring (not a keybox), then the keyring is marked as read only and
   operations just as keyring_insert_keyblock will return
   GPG_ERR_ACCESS.  */
gpg_error_t keydb_add_resource (const char *url, unsigned int flags);

/* Dump some statistics to the log.  */
void keydb_dump_stats (void);

/* Create a new database handle.  A database handle is similar to a
   file handle: it contains a local file position.  This is used when
   searching: subsequent searches resume where the previous search
   left off.  To rewind the position, use keydb_search_reset().  */
KEYDB_HANDLE keydb_new (void);

/* Free all resources owned by the database handle.  */
void keydb_release (KEYDB_HANDLE hd);

/* Set a flag on the handle to suppress use of cached results.  This
   is required for updating a keyring and for key listings.  Fixme:
   Using a new parameter for keydb_new might be a better solution.  */
void keydb_disable_caching (KEYDB_HANDLE hd);

/* Save the last found state and invalidate the current selection
   (i.e., the entry selected by keydb_search() is invalidated and
   something like keydb_get_keyblock() will return an error).  This
   does not change the file position.  This makes it possible to do
   something like:

     keydb_search (hd, ...);  // Result 1.
     keydb_push_found_state (hd);
       keydb_search_reset (hd);
       keydb_search (hd, ...);  // Result 2.
     keydb_pop_found_state (hd);
     keydb_get_keyblock (hd, ...);  // -> Result 1.

   Note: it is only possible to save a single save state at a time.
   In other words, the the save stack only has room for a single
   instance of the state.  */
void keydb_push_found_state (KEYDB_HANDLE hd);

/* Restore the previous save state.  If the saved state is invalid,
   this is equivalent to */
void keydb_pop_found_state (KEYDB_HANDLE hd);

/* Return the file name of the resource in which the current search
   result was found or, if there is no search result, the filename of
   the current resource (i.e., the resource that the file position
   points to).  Note: the filename is not necessarily the URL used to
   open it!

   This function only returns NULL if no handle is specified, in all
   other error cases an empty string is returned.  */
const char *keydb_get_resource_name (KEYDB_HANDLE hd);

/* Return the keyblock last found by keydb_search() in *RET_KB.

   On success, the function returns 0 and the caller must free *RET_KB
   using release_kbnode().  Otherwise, the function returns an error
   code.

   The returned keyblock has the kbnode 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.  */
gpg_error_t keydb_get_keyblock (KEYDB_HANDLE hd, KBNODE *ret_kb);

/* Replace the currently selected keyblock (i.e., the last result
   returned by keydb_search) with the key block in KB.

   This doesn't do anything if --dry-run was specified.

   Returns 0 on success.  Otherwise, it returns an error code.  */
gpg_error_t keydb_update_keyblock (KEYDB_HANDLE hd, kbnode_t kb);

/* Insert a keyblock into one of the underlying keyrings or keyboxes.

   Be default, the keyring / keybox from which the last search result
   came is used.  If there was no previous search result (or
   keydb_search_reset was called), then the keyring / keybox where the
   next search would start is used (i.e., the current file position).

   Note: this doesn't do anything if --dry-run was specified.

   Returns 0 on success.  Otherwise, it returns an error code.  */
gpg_error_t keydb_insert_keyblock (KEYDB_HANDLE hd, kbnode_t kb);

/* Delete the currently selected keyblock.  If you haven't done a
   search yet on this database handle (or called keydb_search_reset),
   then this will return an error.

   Returns 0 on success or an error code, if an error occurs.  */
gpg_error_t keydb_delete_keyblock (KEYDB_HANDLE hd);

/* A database may consists of multiple keyrings / key boxes.  This
   sets the "file position" to the start of the first keyring / key
   box that is writable (i.e., doesn't have the read-only flag set).

   This first tries the primary keyring (the last keyring (not
   keybox!) added using keydb_add_resource() and with
   KEYDB_RESOURCE_FLAG_PRIMARY set).  If that is not writable, then it
   tries the keyrings / keyboxes in the order in which they were
   added.  */
gpg_error_t keydb_locate_writable (KEYDB_HANDLE hd);

/* Rebuild the on-disk caches of all key resources.  */
void keydb_rebuild_caches (int noisy);

/* Return the number of skipped blocks (because they were to large to
   read from a keybox) since the last search reset.  */
unsigned long keydb_get_skipped_counter (KEYDB_HANDLE hd);

/* Clears the current search result and resets the handle's position
   so that the next search starts at the beginning of the database
   (the start of the first resource).

   Returns 0 on success and an error code if an error occured.
   (Currently, this function always returns 0 if HD is valid.)  */
gpg_error_t keydb_search_reset (KEYDB_HANDLE hd);

/* Search the database for keys matching the search description.

   DESC is an array of search terms with NDESC entries.  The search
   terms are or'd together.  That is, the next entry in the DB that
   matches any of the descriptions will be returned.

   Note: this function resumes searching where the last search left
   off (i.e., at the current file position).  If you want to search
   from the start of the database, then you need to first call
   keydb_search_reset().

   If no key matches the search description, returns
   GPG_ERR_NOT_FOUND.  If there was a match, returns 0.  If an error
   occured, returns an error code.

   The returned key is considered to be selected and the raw data can,
   for instance, be returned by calling keydb_get_keyblock().  */
gpg_error_t keydb_search (KEYDB_HANDLE hd, KEYDB_SEARCH_DESC *desc,
                          size_t ndesc, size_t *descindex);

/* Return the first non-legacy key in the database.

   If you want the very first key in the database, you can directly
   call keydb_search with the search description
   KEYDB_SEARCH_MODE_FIRST.  */
gpg_error_t keydb_search_first (KEYDB_HANDLE hd);

/* Return the next key (not the next matching key!).

   Unlike calling keydb_search with KEYDB_SEARCH_MODE_NEXT, this
   function silently skips legacy keys.  */
gpg_error_t keydb_search_next (KEYDB_HANDLE hd);

/* This is a convenience function for searching for keys with a long
   key id.

   Note: this function resumes searching where the last search left
   off.  If you want to search the whole database, then you need to
   first call keydb_search_reset().  */
gpg_error_t keydb_search_kid (KEYDB_HANDLE hd, u32 *kid);

/* This is a convenience function for searching for keys with a long
   (20 byte) fingerprint.  This function ignores legacy keys.

   Note: this function resumes searching where the last search left
   off.  If you want to search the whole database, then you need to
   first call keydb_search_reset().  */
gpg_error_t keydb_search_fpr (KEYDB_HANDLE hd, const byte *fpr);


/*-- pkclist.c --*/
void show_revocation_reason( PKT_public_key *pk, int mode );
int  check_signatures_trust( PKT_signature *sig );

void release_pk_list (PK_LIST pk_list);
int  build_pk_list (ctrl_t ctrl,
                    strlist_t rcpts, PK_LIST *ret_pk_list, unsigned use);
gpg_error_t find_and_check_key (ctrl_t ctrl,
                                const char *name, unsigned int use,
                                int mark_hidden, pk_list_t *pk_list_addr);

int  algo_available( preftype_t preftype, int algo,
		     const union pref_hint *hint );
int  select_algo_from_prefs( PK_LIST pk_list, int preftype,
			     int request, const union pref_hint *hint);
int  select_mdc_from_pklist (PK_LIST pk_list);
void warn_missing_mdc_from_pklist (PK_LIST pk_list);
void warn_missing_aes_from_pklist (PK_LIST pk_list);

/*-- skclist.c --*/
int  random_is_faked (void);
void release_sk_list( SK_LIST sk_list );
gpg_error_t  build_sk_list (strlist_t locusr, SK_LIST *ret_sk_list,
                            unsigned use);

/*-- passphrase.h --*/
unsigned char encode_s2k_iterations (int iterations);
assuan_context_t agent_open (int try, const char *orig_codeset);
void agent_close (assuan_context_t ctx);
int  have_static_passphrase(void);
const char *get_static_passphrase (void);
void set_passphrase_from_string(const char *pass);
void read_passphrase_from_fd( int fd );
void passphrase_clear_cache ( u32 *keyid, const char *cacheid, int algo );
DEK *passphrase_to_dek_ext(u32 *keyid, int pubkey_algo,
                           int cipher_algo, STRING2KEY *s2k, int mode,
                           const char *tryagain_text,
                           const char *custdesc, const char *custprompt,
                           int *canceled);
DEK *passphrase_to_dek( u32 *keyid, int pubkey_algo,
			int cipher_algo, STRING2KEY *s2k, int mode,
                        const char *tryagain_text, int *canceled);
void set_next_passphrase( const char *s );
char *get_last_passphrase(void);
void next_to_last_passphrase(void);

void emit_status_need_passphrase (u32 *keyid, u32 *mainkeyid, int pubkey_algo);

#define FORMAT_KEYDESC_NORMAL  0
#define FORMAT_KEYDESC_IMPORT  1
#define FORMAT_KEYDESC_EXPORT  2
#define FORMAT_KEYDESC_DELKEY  3
char *gpg_format_keydesc (PKT_public_key *pk, int mode, int escaped);


/*-- getkey.c --*/

/* Cache a copy of a public key in the public key cache.  PK is not
   cached if caching is disabled (via getkey_disable_caches), if
   PK->FLAGS.DONT_CACHE is set, we don't know how to derive a key id
   from the public key (e.g., unsupported algorithm), or a key with
   the key id is already in the cache.

   The public key packet is copied into the cache using
   copy_public_key.  Thus, any secret parts are not copied, for
   instance.

   This cache is filled by get_pubkey and is read by get_pubkey and
   get_pubkey_fast.  */
void cache_public_key( PKT_public_key *pk );

/* Disable and drop the public key cache (which is filled by
   cache_public_key and get_pubkey).  Note: there is currently no way
   to reenable this cache.  */
void getkey_disable_caches(void);

/* Return the public key with the key id KEYID and store it in *PK.
   The resources in *PK should be released using
   release_public_key_parts().  This function also stores a copy of
   the public key in the user id cache (see cache_public_key).

   If PK is NULL, this function just stores the public key in the
   cache and returns the usual return code.

   PK->REQ_USAGE (which is a mask of PUBKEY_USAGE_SIG,
   PUBKEY_USAGE_ENC and PUBKEY_USAGE_CERT) is passed through to the
   lookup function.  If this is non-zero, only keys with the specified
   usage will be returned.  As such, it is essential that
   PK->REQ_USAGE be correctly initialized!

   Returns 0 on success, GPG_ERR_NO_PUBKEY if there is no public key
   with the specified key id, or another error code if an error
   occurs.

   If the data was not read from the cache, then the self-signed data
   has definately been merged into the public key using
   merge_selfsigs.  */
int get_pubkey( PKT_public_key *pk, u32 *keyid );

/* Similar to get_pubkey, but it does not take PK->REQ_USAGE into
   account nor does it merge in the self-signed data.  This function
   also only considers primary keys.  It is intended to be used as a
   quick check of the key to avoid recursion.  It should only be used
   in very certain cases.  Like get_pubkey and unlike any of the other
   lookup functions, this function also consults the user id cache
   (see cache_public_key).

   Return the public key in *PK.  The resources in *PK should be
   released using release_public_key_parts().  */
int get_pubkey_fast ( PKT_public_key *pk, u32 *keyid );

/* Return the key block for the key with key id KEYID or NULL, if an
   error occurs.  Use release_kbnode() to release the key block.

   The self-signed data has already been merged into the public key
   using merge_selfsigs.  */
KBNODE get_pubkeyblock( u32 *keyid );

/* Find a public key identified by the name NAME.

   If name appears to be a valid valid RFC822 mailbox (i.e., email
   address) and auto key lookup is enabled (no_akl == 0), then the
   specified auto key lookup methods (--auto-key-lookup) are used to
   import the key into the local keyring.  Otherwise, just the local
   keyring is consulted.


   If RETCTX is not NULL, then the constructed context is returned in
   *RETCTX so that getpubkey_next can be used to get subsequent
   results.  In this case, getkey_end() must be used to free the
   search context.  If RETCTX is not NULL, then RET_KDBHD must be
   NULL.

   If PK is not NULL, the public key of the first result is returned
   in *PK.  Note: PK->REQ_USAGE must be valid!!!  PK->REQ_USAGE is
   passed through to the lookup function and is a mask of
   PUBKEY_USAGE_SIG, PUBKEY_USAGE_ENC and PUBKEY_USAGE_CERT.  If this
   is non-zero, only keys with the specified usage will be returned.
   Note: The self-signed data has already been merged into the public
   key using merge_selfsigs.  Free *PK by calling
   release_public_key_parts (or, if PK was allocated using xfree, you
   can use free_public_key, which calls release_public_key_parts(PK)
   and then xfree(PK)).

   NAME is a string, which is turned into a search query using
   classify_user_id.

   If RET_KEYBLOCK is not NULL, the keyblock is returned in
   *RET_KEYBLOCK.  This should be freed using release_kbnode().

   If RET_KDBHD is not NULL, then the new database handle used to
   conduct the search is returned in *RET_KDBHD.  This can be used to
   get subsequent results using keydb_search_next or to modify the
   returned record.  Note: in this case, no advanced filtering is done
   for subsequent results (e.g., PK->REQ_USAGE is not respected).
   Unlike RETCTX, this is always returned.

   If INCLUDE_UNUSABLE is set, then unusable keys (see the
   documentation for skip_unusable for an exact definition) are
   skipped unless they are looked up by key id or by fingerprint.

   If NO_AKL is set, then the auto key locate functionality is
   disabled and only the local key ring is considered.  Note: the
   local key ring is consulted even if local is not in the
   --auto-key-locate option list!

   This function returns 0 on success.  Otherwise, an error code is
   returned.  In particular, GPG_ERR_NO_PUBKEY or GPG_ERR_NO_SECKEY
   (if want_secret is set) is returned if the key is not found.  */
int get_pubkey_byname (ctrl_t ctrl,
                       GETKEY_CTX *retctx, PKT_public_key *pk,
		       const char *name,
                       KBNODE *ret_keyblock, KEYDB_HANDLE *ret_kdbhd,
		       int include_unusable, int no_akl );

/* Return the public key with the key id KEYID and store it in *PK.
   The resources should be released using release_public_key_parts().

   Unlike other lookup functions, PK may not be NULL.  PK->REQ_USAGE
   is passed through to the lookup function and is a mask of
   PUBKEY_USAGE_SIG, PUBKEY_USAGE_ENC and PUBKEY_USAGE_CERT.  Thus, it
   must be valid!  If this is non-zero, only keys with the specified
   usage will be returned.

   Returns 0 on success.  If a public key with the specified key id is
   not found or a secret key is not available for that public key, an
   error code is returned.  Note: this function ignores legacy keys.
   An error code is also return if an error occurs.

   The self-signed data has already been merged into the public key
   using merge_selfsigs.  */
gpg_error_t get_seckey (PKT_public_key *pk, u32 *keyid);

/* Lookup a key with the specified fingerprint.

   If PK is not NULL, the public key of the first result is returned
   in *PK.  Note: this function does an exact search and thus the
   returned public key may be a subkey rather than the primary key.
   Note: The self-signed data has already been merged into the public
   key using merge_selfsigs.  Free *PK by calling
   release_public_key_parts (or, if PK was allocated using xfree, you
   can use free_public_key, which calls release_public_key_parts(PK)
   and then xfree(PK)).

   If PK->REQ_USAGE is set, it is used to filter the search results.
   (Thus, if PK is not NULL, PK->REQ_USAGE must be valid!!!)  See the
   documentation for finish_lookup to understand exactly how this is
   used.

   If R_KEYBLOCK is not NULL, then the first result's keyblock is
   returned in *R_KEYBLOCK.  This should be freed using
   release_kbnode().

   FPRINT is a byte array whose contents is the fingerprint to use as
   the search term.  FPRINT_LEN specifies the length of the
   fingerprint (in bytes).  Currently, only 16 and 20-byte
   fingerprints are supported.  */
int get_pubkey_byfprint (PKT_public_key *pk,  kbnode_t *r_keyblock,
                         const byte *fprint, size_t fprint_len);

/* This function is similar to get_pubkey_byfprint, but it doesn't
   merge the self-signed data into the public key and subkeys or into
   the user ids.  It also doesn't add the key to the user id cache.
   Further, this function ignores PK->REQ_USAGE.

   This function is intended to avoid recursion and, as such, should
   only be used in very specific situations.

   Like get_pubkey_byfprint, PK may be NULL.  In that case, this
   function effectively just checks for the existence of the key.  */
int get_pubkey_byfprint_fast (PKT_public_key *pk,
                              const byte *fprint, size_t fprint_len);

/* Return whether a secret key is available for the public key with
   key id KEYID.  This function ignores legacy keys.  Note: this is
   just a fast check and does not tell us whether the secret key is
   valid; this check merely indicates whether there is some secret key
   with the specified key id.  */
int have_secret_key_with_kid (u32 *keyid);

/* Look up a secret key.

   If PK is not NULL, the public key of the first result is returned
   in *PK.  Note: PK->REQ_USAGE must be valid!!!  If PK->REQ_USAGE is
   set, it is used to filter the search results.  See the
   documentation for finish_lookup to understand exactly how this is
   used.  Note: The self-signed data has already been merged into the
   public key using merge_selfsigs.  Free *PK by calling
   release_public_key_parts (or, if PK was allocated using xfree, you
   can use free_public_key, which calls release_public_key_parts(PK)
   and then xfree(PK)).

   If --default-key was set, then the specified key is looked up.  (In
   this case, the default key is returned even if it is considered
   unusable.  See the documentation for skip_unusable for exactly what
   this means.)

   Otherwise, this initiates a DB scan that returns all keys that are
   usable (see previous paragraph for exactly what usable means) and
   for which a secret key is available.

   This function returns the first match.  Additional results can be
   returned using getkey_next.  */
gpg_error_t get_seckey_default (PKT_public_key *pk);

/* Search for keys matching some criteria.

   If RETCTX is not NULL, then the constructed context is returned in
   *RETCTX so that getpubkey_next can be used to get subsequent
   results.  In this case, getkey_end() must be used to free the
   search context.  If RETCTX is not NULL, then RET_KDBHD must be
   NULL.

   If PK is not NULL, the public key of the first result is returned
   in *PK.  Note: PK->REQ_USAGE must be valid!!!  If PK->REQ_USAGE is
   set, it is used to filter the search results.  See the
   documentation for finish_lookup to understand exactly how this is
   used.  Note: The self-signed data has already been merged into the
   public key using merge_selfsigs.  Free *PK by calling
   release_public_key_parts (or, if PK was allocated using xfree, you
   can use free_public_key, which calls release_public_key_parts(PK)
   and then xfree(PK)).

   If NAMES is not NULL, then a search query is constructed using
   classify_user_id on each of the strings in the list.  (Recall: the
   database does an OR of the terms, not an AND.)  If NAMES is
   NULL, then all results are returned.

   If WANT_SECRET is set, then only keys with an available secret key
   (either locally or via key registered on a smartcard) are returned.

   This function does not skip unusable keys (see the documentation
   for skip_unusable for an exact definition).

   If RET_KEYBLOCK is not NULL, the keyblock is returned in
   *RET_KEYBLOCK.  This should be freed using release_kbnode().

   This function returns 0 on success.  Otherwise, an error code is
   returned.  In particular, GPG_ERR_NO_PUBKEY or GPG_ERR_NO_SECKEY
   (if want_secret is set) is returned if the key is not found.  */
gpg_error_t getkey_bynames (getkey_ctx_t *retctx, PKT_public_key *pk,
                            strlist_t names, int want_secret,
                            kbnode_t *ret_keyblock);

/* Search for keys matching some criteria.

   If RETCTX is not NULL, then the constructed context is returned in
   *RETCTX so that getpubkey_next can be used to get subsequent
   results.  In this case, getkey_end() must be used to free the
   search context.  If RETCTX is not NULL, then RET_KDBHD must be
   NULL.

   If PK is not NULL, the public key of the first result is returned
   in *PK.  Note: PK->REQ_USAGE must be valid!!!  If PK->REQ_USAGE is
   set, it is used to filter the search results.  See the
   documentation for finish_lookup to understand exactly how this is
   used.  Note: The self-signed data has already been merged into the
   public key using merge_selfsigs.  Free *PK by calling
   release_public_key_parts (or, if PK was allocated using xfree, you
   can use free_public_key, which calls release_public_key_parts(PK)
   and then xfree(PK)).

   If NAME is not NULL, then a search query is constructed using
   classify_user_id on the string.  In this case, even unusable keys
   (see the documentation for skip_unusable for an exact definition of
   unusable) are returned.  Otherwise, if --default-key was set, then
   that key is returned (even if it is unusable).  If neither of these
   conditions holds, then the first usable key is returned.

   If WANT_SECRET is set, then only keys with an available secret key
   (either locally or via key registered on a smartcard) are returned.

   This function does not skip unusable keys (see the documentation
   for skip_unusable for an exact definition).

   If RET_KEYBLOCK is not NULL, the keyblock is returned in
   *RET_KEYBLOCK.  This should be freed using release_kbnode().

   This function returns 0 on success.  Otherwise, an error code is
   returned.  In particular, GPG_ERR_NO_PUBKEY or GPG_ERR_NO_SECKEY
   (if want_secret is set) is returned if the key is not found.

   FIXME: We also have the get_pubkey_byname function which has a
   different semantic.  Should be merged with this one.  */
gpg_error_t getkey_byname (getkey_ctx_t *retctx, PKT_public_key *pk,
                           const char *name, int want_secret,
                           kbnode_t *ret_keyblock);

/* Return the next search result.

   If PK is not NULL, the public key of the next result is returned in
   *PK.  Note: The self-signed data has already been merged into the
   public key using merge_selfsigs.  Free *PK by calling
   release_public_key_parts (or, if PK was allocated using xfree, you
   can use free_public_key, which calls release_public_key_parts(PK)
   and then xfree(PK)).

   The self-signed data has already been merged into the public key
   using merge_selfsigs.  */
gpg_error_t getkey_next (getkey_ctx_t ctx, PKT_public_key *pk,
                         kbnode_t *ret_keyblock);

/* Release any resources used by a key listing content.  This must be
   called on the context returned by, e.g., getkey_byname.  */
void getkey_end (getkey_ctx_t ctx);

/* Return the database handle used by this context.  The context still
   owns the handle.  */
KEYDB_HANDLE get_ctx_handle(GETKEY_CTX ctx);

/* Enumerate some secret keys (specifically, those specified with
   --default-key and --try-secret-key).  Use the following procedure:

    1) Initialize a void pointer to NULL
    2) Pass a reference to this pointer to this function (content)
       and provide space for the secret key (sk)
    3) Call this function as long as it does not return an error (or
       until you are done).  The error code GPG_ERR_EOF indicates the
       end of the listing.
    4) Call this function a last time with SK set to NULL,
       so that can free it's context.

   In pseudo-code:

     void *ctx = NULL;
     PKT_public_key *sk = xmalloc_clear (sizeof (*sk));
     gpg_error_t err;

     while ((err = enum_secret_keys (&ctx, sk)))
       {
         // Process SK.

	 if (done)
	   break;

         free_public_key (sk);
	 sk = xmalloc_clear (sizeof (*sk));
       }

     // Release any resources used by CTX.
     enum_secret_keys (&ctx, NULL);
     free_public_key (sk);

     if (gpg_err_code (err) != GPG_ERR_EOF)
       ; // An error occured.
 */
gpg_error_t enum_secret_keys (void **context, PKT_public_key *pk);

/* Set the mainkey_id fields for all keys in KEYBLOCK.  This is
   usually done by merge_selfsigs but at some places we only need the
   main_kid not a full merge.  The function also guarantees that all
   pk->keyids are computed. */
void setup_main_keyids (kbnode_t keyblock);

/* KEYBLOCK corresponds to a public key block.  This function merges
   much of the information from the self-signed data into the public
   key, public subkey and user id data structures.  If you use the
   high-level search API (e.g., get_pubkey) for looking up key blocks,
   then you don't need to call this function.  This function is
   useful, however, if you change the keyblock, e.g., by adding or
   removing a self-signed data packet.  */
void merge_keys_and_selfsig( KBNODE keyblock );

char*get_user_id_string_native( u32 *keyid );
char*get_long_user_id_string( u32 *keyid );
char*get_user_id( u32 *keyid, size_t *rn );
char*get_user_id_native( u32 *keyid );
char *get_user_id_byfpr (const byte *fpr, size_t *rn);
char *get_user_id_byfpr_native (const byte *fpr);

void release_akl(void);
int parse_auto_key_locate(char *options);

/*-- keyid.c --*/
int pubkey_letter( int algo );
char *pubkey_string (PKT_public_key *pk, char *buffer, size_t bufsize);
#define PUBKEY_STRING_SIZE 32
u32 v3_keyid (gcry_mpi_t a, u32 *ki);
void hash_public_key( gcry_md_hd_t md, PKT_public_key *pk );
size_t keystrlen(void);
const char *keystr(u32 *keyid);
const char *keystr_with_sub (u32 *main_kid, u32 *sub_kid);
const char *keystr_from_pk(PKT_public_key *pk);
const char *keystr_from_pk_with_sub (PKT_public_key *main_pk,
                                     PKT_public_key *sub_pk);
const char *keystr_from_desc(KEYDB_SEARCH_DESC *desc);
u32 keyid_from_pk( PKT_public_key *pk, u32 *keyid );
u32 keyid_from_sig( PKT_signature *sig, u32 *keyid );
u32 keyid_from_fingerprint(const byte *fprint, size_t fprint_len, u32 *keyid);
byte *namehash_from_uid(PKT_user_id *uid);
unsigned nbits_from_pk( PKT_public_key *pk );
const char *datestr_from_pk( PKT_public_key *pk );
const char *datestr_from_sig( PKT_signature *sig );
const char *expirestr_from_pk( PKT_public_key *pk );
const char *expirestr_from_sig( PKT_signature *sig );
const char *revokestr_from_pk( PKT_public_key *pk );
const char *usagestr_from_pk (PKT_public_key *pk, int fill);
const char *colon_strtime (u32 t);
const char *colon_datestr_from_pk (PKT_public_key *pk);
const char *colon_datestr_from_sig (PKT_signature *sig);
const char *colon_expirestr_from_sig (PKT_signature *sig);
byte *fingerprint_from_pk( PKT_public_key *pk, byte *buf, size_t *ret_len );
char *hexfingerprint (PKT_public_key *pk);
gpg_error_t keygrip_from_pk (PKT_public_key *pk, unsigned char *array);
gpg_error_t hexkeygrip_from_pk (PKT_public_key *pk, char **r_grip);


/*-- kbnode.c --*/
KBNODE new_kbnode( PACKET *pkt );
KBNODE clone_kbnode( KBNODE node );
void release_kbnode( KBNODE n );
void delete_kbnode( KBNODE node );
void add_kbnode( KBNODE root, KBNODE node );
void insert_kbnode( KBNODE root, KBNODE node, int pkttype );
void move_kbnode( KBNODE *root, KBNODE node, KBNODE where );
void remove_kbnode( KBNODE *root, KBNODE node );
KBNODE find_prev_kbnode( KBNODE root, KBNODE node, int pkttype );
KBNODE find_next_kbnode( KBNODE node, int pkttype );
KBNODE find_kbnode( KBNODE node, int pkttype );
KBNODE walk_kbnode( KBNODE root, KBNODE *context, int all );
void clear_kbnode_flags( KBNODE n );
int  commit_kbnode( KBNODE *root );
void dump_kbnode( KBNODE node );

#endif /*G10_KEYDB_H*/