From 160862978628b07ed5150ec2c8abad6af1656bc3 Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Wed, 13 Jan 2016 10:16:27 +0100
Subject: [PATCH] kbx: Implement keybox_lock for use by gpg.

* kbx/keybox-defs.h: Include dotlock.h and logging.h.
(CONST_KB_NAME): Remove.  Replace usage by KB_NAME.
(struct keybox_name): Add field "lockhd".
* kbx/keybox-init.c (keybox_register_file): Init LOCKHD.
(keybox_lock): Chnage to return gpg_error_t.  Implement locking.
--

The keybox locking for gpg was not implemented - This needs to be
fixed of course.

Signed-off-by: Werner Koch <wk@gnupg.org>
---
 kbx/keybox-defs.h | 10 ++++----
 kbx/keybox-init.c | 58 +++++++++++++++++++++++++++++++++++++++--------
 kbx/keybox.h      |  2 +-
 3 files changed, 55 insertions(+), 15 deletions(-)

diff --git a/kbx/keybox-defs.h b/kbx/keybox-defs.h
index 6fe984762..6af544810 100644
--- a/kbx/keybox-defs.h
+++ b/kbx/keybox-defs.h
@@ -40,6 +40,8 @@
    fixme: Better use the LIBOBJ mechnism. */
 #include "../common/types.h"
 #include "../common/stringhelp.h"
+#include "../common/dotlock.h"
+#include "../common/logging.h"
 
 #include "keybox.h"
 
@@ -48,7 +50,6 @@ typedef struct keyboxblob *KEYBOXBLOB;
 
 
 typedef struct keybox_name *KB_NAME;
-typedef struct keybox_name const *CONST_KB_NAME;
 struct keybox_name
 {
   /* Link to the next resources, so that we can walk all
@@ -58,14 +59,15 @@ struct keybox_name
   /* True if this is a keybox with secret keys.  */
   int secret;
 
-  /*DOTLOCK lockhd;*/
-
   /* A table with all the handles accessing this resources.
      HANDLE_TABLE_SIZE gives the allocated length of this table unused
      entrues are set to NULL.  HANDLE_TABLE may be NULL. */
   KEYBOX_HANDLE *handle_table;
   size_t handle_table_size;
 
+  /* The lock handle or NULL it not yet initialized.  */
+  dotlock_t lockhd;
+
   /* Not yet used.  */
   int is_locked;
 
@@ -85,7 +87,7 @@ struct keybox_found_s
 };
 
 struct keybox_handle {
-  CONST_KB_NAME kb;
+  KB_NAME kb;
   int secret;             /* this is for a secret keybox */
   FILE *fp;
   int eof;
diff --git a/kbx/keybox-init.c b/kbx/keybox-init.c
index 3ff592eaf..cfee7b8f7 100644
--- a/kbx/keybox-init.c
+++ b/kbx/keybox-init.c
@@ -60,7 +60,7 @@ keybox_register_file (const char *fname, int secret, void **r_token)
   kr->handle_table = NULL;
   kr->handle_table_size = 0;
 
-  /* kr->lockhd = NULL;*/
+  kr->lockhd = NULL;
   kr->is_locked = 0;
   kr->did_full_scan = 0;
   /* keep a list of all issued pointers */
@@ -261,17 +261,55 @@ _keybox_close_file (KEYBOX_HANDLE hd)
 
 
 /*
- * Lock the keybox at handle HD, or unlock if YES is false.  Note that
- * we currently ignore the handle and lock all registered keyboxes.
+ * Lock the keybox at handle HD, or unlock if YES is false.
  */
-int
+gpg_error_t
 keybox_lock (KEYBOX_HANDLE hd, int yes)
 {
-  /* FIXME: We need to implement it before we can use it with gpg.
-     gpgsm does the locking in its local keydb.c driver; this should
-     be changed as well.  */
+  gpg_error_t err;
+  KB_NAME kb = hd->kb;
 
-  (void)hd;
-  (void)yes;
-  return 0;
+  if (!keybox_is_writable ((void*)kb))
+    return 0;
+
+  /* Make sure the lock handle has been created.  */
+  if (!kb->lockhd)
+    {
+      kb->lockhd = dotlock_create (kb->fname, 0);
+      if (!kb->lockhd)
+        {
+          /* Unfortuntaley dotlock_create does not properly set ERRNO.  */
+          log_info ("can't allocate lock for '%s'\n", kb->fname );
+          return gpg_error (GPG_ERR_GENERAL);
+        }
+    }
+
+  if (yes) /* Take the lock.  */
+    {
+      if (kb->is_locked)
+        ;
+      else if (!dotlock_take (kb->lockhd, -1))
+        kb->is_locked = 1;
+      else
+        {
+          /* Unfortuntaley dotlock_take does not properly set ERRNO.  */
+          log_info ("can't lock '%s'\n", kb->fname );
+          err = gpg_error (GPG_ERR_GENERAL);
+        }
+    }
+  else /* Release the lock.  */
+    {
+      if (!kb->is_locked)
+        ;
+      else if (!dotlock_release (kb->lockhd))
+        kb->is_locked = 0;
+      else
+        {
+          /* Unfortuntaley dotlock_release does not properly set ERRNO.  */
+          log_info ("can't unlock '%s'\n", kb->fname );
+          err = gpg_error (GPG_ERR_GENERAL);
+        }
+    }
+
+  return err;
 }
diff --git a/kbx/keybox.h b/kbx/keybox.h
index acd7a4f89..9f91c53bd 100644
--- a/kbx/keybox.h
+++ b/kbx/keybox.h
@@ -76,7 +76,7 @@ void keybox_pop_found_state (KEYBOX_HANDLE hd);
 const char *keybox_get_resource_name (KEYBOX_HANDLE hd);
 int keybox_set_ephemeral (KEYBOX_HANDLE hd, int yes);
 
-int keybox_lock (KEYBOX_HANDLE hd, int yes);
+gpg_error_t keybox_lock (KEYBOX_HANDLE hd, int yes);
 
 /*-- keybox-file.c --*/
 /* Fixme: This function does not belong here: Provide a better