gpg: Move documentation from keydb.h to keydb.c and getkey.c.

--

When using tags (e.g. GNU global) to navigate the source code it is
way easier to have the documentation close to the function we are
looking at.  Having the documentation in the header file would require
an extra manual lookup to understand the function.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 321 insertions, 24 deletions

diff --git a/g10/getkey.c b/g10/getkey.c
index 1df7287ba..d6e27e6bd 100644
--- a/g10/getkey.c
+++ b/g10/getkey.c
@@ -155,7 +155,18 @@ print_stats ()
 #endif
 
 
-/* For documentation see keydb.h.  */
+/* 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)
 {
@@ -344,7 +355,9 @@ cache_user_id (KBNODE keyblock)
 }
 
 
-/* For documentation see keydb.h.  */
+/* 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 ()
 {
@@ -653,7 +666,27 @@ pk_from_block (GETKEY_CTX ctx, PKT_public_key * pk, KBNODE keyblock,
 }
 
 
-/* For documentation see keydb.h.  */
+/* Return the public key with the key id KEYID and store it at 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 definitely been merged into the public key using
+ * merge_selfsigs.  */
 int
 get_pubkey (PKT_public_key * pk, u32 * keyid)
 {
@@ -728,7 +761,16 @@ leave:
 }
 
 
-/* For documentation see keydb.h.  */
+/* 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)
 {
@@ -795,8 +837,12 @@ get_pubkey_fast (PKT_public_key * pk, u32 * keyid)
 }
 
 
-/* For documentation see keydb.h.  */
-KBNODE
+/* 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_t
 get_pubkeyblock (u32 * keyid)
 {
   struct getkey_ctx_s ctx;
@@ -820,7 +866,23 @@ get_pubkeyblock (u32 * keyid)
 }
 
 
-/* For documentation see keydb.h.  */
+/* Return the public key with the key id KEYID iff the secret key is
+ * available and store it at 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)
 {
@@ -1070,7 +1132,56 @@ key_byname (GETKEY_CTX *retctx, strlist_t namelist,
 }
 
 
-/* For documentation see keydb.h.  */
+/* Find a public key identified by 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,
@@ -1334,11 +1445,34 @@ get_pubkey_byname (ctrl_t ctrl, GETKEY_CTX * retctx, PKT_public_key * pk,
 }
 
 
-/* For documentation see keydb.h.
-
-   FIXME: We should replace this with the _byname function.  This can
-   be done by creating a userID conforming to the unified fingerprint
-   style.  */
+/* 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.
+ *
+ * FIXME: We should replace this with the _byname function.  This can
+ * be done by creating a userID conforming to the unified fingerprint
+ * style.  */
 int
 get_pubkey_byfprint (PKT_public_key *pk, kbnode_t *r_keyblock,
 		     const byte * fprint, size_t fprint_len)
@@ -1382,7 +1516,16 @@ get_pubkey_byfprint (PKT_public_key *pk, kbnode_t *r_keyblock,
 }
 
 
-/* For documentation see keydb.h.  */
+/* 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)
@@ -1556,7 +1699,30 @@ parse_def_secret_key (ctrl_t ctrl)
   return NULL;
 }
 
-/* For documentation see keydb.h.  */
+
+/* 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 (ctrl_t ctrl, PKT_public_key *pk)
 {
@@ -1577,8 +1743,44 @@ get_seckey_default (ctrl_t ctrl, PKT_public_key *pk)
 
   return err;
 }
+
+
 
-/* For documentation see keydb.h.  */
+/* 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)
@@ -1588,7 +1790,46 @@ getkey_bynames (getkey_ctx_t *retctx, PKT_public_key *pk,
 }
 
 
-/* For documentation see keydb.h.  */
+/* Search for one key 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 (ctrl_t ctrl, getkey_ctx_t *retctx, PKT_public_key *pk,
                const char *name, int want_secret, kbnode_t *ret_keyblock)
@@ -1620,7 +1861,22 @@ getkey_byname (ctrl_t ctrl, getkey_ctx_t *retctx, PKT_public_key *pk,
 }
 
 
-/* For documentation see keydb.h.  */
+/* 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)).
+ *
+ * RET_KEYBLOCK can be given as NULL; if it is not NULL it the entire
+ * found keyblock wis retruned hich must be released with
+ * release_kbnode.  If the function returns an error NULL is stored at
+ * RET_KEYBLOCK.
+ *
+ * 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)
 {
@@ -1641,7 +1897,8 @@ getkey_next (getkey_ctx_t ctx, PKT_public_key *pk, kbnode_t *ret_keyblock)
 }
 
 
-/* For documentation see keydb.h.  */
+/* Release any resources used by a key listing context.  This must be
+ * called on the context returned by, e.g., getkey_byname.  */
 void
 getkey_end (getkey_ctx_t ctx)
 {
@@ -1660,7 +1917,10 @@ getkey_end (getkey_ctx_t ctx)
  ************* Merging stuff ********************
  ************************************************/
 
-/* For documentation see keydb.h.  */
+/* 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)
 {
@@ -1689,7 +1949,13 @@ setup_main_keyids (kbnode_t keyblock)
 }
 
 
-/* For documentation see keydb.h.  */
+/* 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)
 {
@@ -3139,7 +3405,38 @@ found:
 }
 
 
-/* For documentation see keydb.h.  */
+/* 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));
+ *
+ *   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 occurred.
+ */
 gpg_error_t
 enum_secret_keys (ctrl_t ctrl, void **context, PKT_public_key *sk)
 {
@@ -3402,8 +3699,8 @@ get_user_id_byfpr_native (const byte *fpr)
 }
 
 
-
-/* For documentation see keydb.h.  */
+/* Return the database handle used by this context.  The context still
+   owns the handle.  */
 KEYDB_HANDLE
 get_ctx_handle (GETKEY_CTX ctx)
 {