libkadm5 should allow persistent locks

libkadm5 should have a way to persistently lock the databases to avoid
wasting time on closing and reopening.  These patches implement
persistent exclusive locks for local access only.

ticket: new
target_version: 1.3

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@14914 dc483132-0cff-0310-8789-dd5450dbe970

10 files changed, 81 insertions, 7 deletions

diff --git a/src/lib/kadm5/ChangeLog b/src/lib/kadm5/ChangeLog
index bed5188..6a91bf4 100644
--- a/src/lib/kadm5/ChangeLog
+++ b/src/lib/kadm5/ChangeLog
@@ -1,3 +1,10 @@
+2002-10-08  Tom Yu  <tlyu@mit.edu>
+
+	* adb.h (struct _osa_adb_db_ent_t): Add opencnt, which keeps track
+	of how many times an open was attempted on the adb.
+
+	* admin.h: Add kadm5_lock and kadm5_unlock.
+
 2002-09-18  Ken Raeburn  <raeburn@mit.edu>
 
 	* admin.h (struct __krb5_realm_params): New field
diff --git a/src/lib/kadm5/adb.h b/src/lib/kadm5/adb.h
index 0277aba..7b49adc 100644
--- a/src/lib/kadm5/adb.h
+++ b/src/lib/kadm5/adb.h
@@ -47,6 +47,7 @@ typedef struct _osa_adb_db_ent_t {
      BTREEINFO	btinfo;
      char	*filename;
      osa_adb_lock_t lock;
+     int	opencnt;
 } osa_adb_db_ent, *osa_adb_db_t, *osa_adb_princ_t, *osa_adb_policy_t;
 
 /* an osa_pw_hist_ent stores all the key_datas for a single password */
diff --git a/src/lib/kadm5/admin.h b/src/lib/kadm5/admin.h
index 9c366ff..c2236ae 100644
--- a/src/lib/kadm5/admin.h
+++ b/src/lib/kadm5/admin.h
@@ -330,6 +330,8 @@ kadm5_ret_t    kadm5_init_with_creds(char *client_name,
 				     krb5_ui_4 api_version,
 				     void **server_handle);
 #endif
+kadm5_ret_t    kadm5_lock(void *server_handle);
+kadm5_ret_t    kadm5_unlock(void *server_handle);
 kadm5_ret_t    kadm5_flush(void *server_handle);
 kadm5_ret_t    kadm5_destroy(void *server_handle);
 kadm5_ret_t    kadm5_create_principal(void *server_handle,
diff --git a/src/lib/kadm5/clnt/ChangeLog b/src/lib/kadm5/clnt/ChangeLog
index ebee3a1..7d393c0 100644
--- a/src/lib/kadm5/clnt/ChangeLog
+++ b/src/lib/kadm5/clnt/ChangeLog
@@ -1,3 +1,10 @@
+2002-10-08  Tom Yu  <tlyu@mit.edu>
+
+	* Makefile.in (LIBMINOR): Bump.
+
+	* client_init.c (kadm5_lock, kadm5_unlock): Add stubs that error
+	out, since these are not supported on the client side.
+
 2002-09-18  Ken Raeburn  <raeburn@mit.edu>
 
 	* client_init.c (_kadm5_init_any): If creating a new ccache, put
diff --git a/src/lib/kadm5/clnt/Makefile.in b/src/lib/kadm5/clnt/Makefile.in
index 2908f5c..3e4fb8c 100644
--- a/src/lib/kadm5/clnt/Makefile.in
+++ b/src/lib/kadm5/clnt/Makefile.in
@@ -6,7 +6,7 @@ LOCALINCLUDES = -I$(BUILDTOP)/include/kadm5
 
 LIB=kadm5clnt
 LIBMAJOR=5
-LIBMINOR=0
+LIBMINOR=1
 STOBJLISTS=../OBJS.ST OBJS.ST
 SHLIB_EXPDEPS=\
 	$(TOPLIBD)/libgssrpc$(SHLIBEXT) \
diff --git a/src/lib/kadm5/clnt/client_init.c b/src/lib/kadm5/clnt/client_init.c
index 4e0b53f..247af87 100644
--- a/src/lib/kadm5/clnt/client_init.c
+++ b/src/lib/kadm5/clnt/client_init.c
@@ -605,6 +605,17 @@ kadm5_destroy(void *server_handle)
 
      return code;
 }
+/* not supported on client */
+kadm5_ret_t kadm5_lock(void *server_handle)
+{
+    return EINVAL;
+}
+
+/* not supported on client */
+kadm5_ret_t kadm5_unlock(void *server_handle)
+{
+    return EINVAL;
+}
 
 kadm5_ret_t kadm5_flush(void *server_handle)
 {
diff --git a/src/lib/kadm5/srv/ChangeLog b/src/lib/kadm5/srv/ChangeLog
index f575d90..e7e569e 100644
--- a/src/lib/kadm5/srv/ChangeLog
+++ b/src/lib/kadm5/srv/ChangeLog
@@ -1,3 +1,14 @@
+2002-10-08  Tom Yu  <tlyu@mit.edu>
+
+	* adb_openclose.c (osa_adb_init_db): Reset opencnt.
+	(osa_adb_open_and_lock): Don't open multiple times; merely
+	increment opencnt if already open.
+	(osa_adb_close_and_unlock): Decrement opencnt instead of
+	unconditionaly closing.
+
+	* server_init.c (kadm5_lock, kadm5_unlock): New functions to
+	support persistent exclusive locks across multiple API calls.
+
 2002-08-29  Ken Raeburn  <raeburn@mit.edu>
 
 	* Makefile.in: Revert $(S)=>/ change, for Windows support.
diff --git a/src/lib/kadm5/srv/Makefile.in b/src/lib/kadm5/srv/Makefile.in
index 5dc71e4..11fc1b6 100644
--- a/src/lib/kadm5/srv/Makefile.in
+++ b/src/lib/kadm5/srv/Makefile.in
@@ -10,7 +10,7 @@ DEFINES = @HESIOD_DEFS@
 
 LIB=kadm5srv
 LIBMAJOR=5
-LIBMINOR=0
+LIBMINOR=1
 STOBJLISTS=../OBJS.ST OBJS.ST
 SHLIB_EXPDEPS=\
 	$(TOPLIBD)/libgssrpc$(SHLIBEXT) \
diff --git a/src/lib/kadm5/srv/adb_openclose.c b/src/lib/kadm5/srv/adb_openclose.c
index 12219cd..7bb671e 100644
--- a/src/lib/kadm5/srv/adb_openclose.c
+++ b/src/lib/kadm5/srv/adb_openclose.c
@@ -214,6 +214,7 @@ osa_adb_ret_t osa_adb_init_db(osa_adb_db_t *dbp, char *filename,
      db->lock = &lockp->lockinfo;
      db->lock->refcnt++;
 
+     db->opencnt = 0;
      db->filename = strdup(filename);
      db->magic = magic;
 
@@ -369,10 +370,12 @@ osa_adb_ret_t osa_adb_open_and_lock(osa_adb_princ_t db, int locktype)
      ret = osa_adb_get_lock(db, locktype);
      if (ret != OSA_ADB_OK)
 	  return ret;
-     
+     if (db->opencnt)
+	  goto open_ok;
+
      db->db = dbopen(db->filename, O_RDWR, 0600, DB_BTREE, &db->btinfo);
      if (db->db != NULL)
-	  return OSA_ADB_OK;
+	 goto open_ok;
      switch (errno) {
 #ifdef EFTYPE
      case EFTYPE:
@@ -380,18 +383,23 @@ osa_adb_ret_t osa_adb_open_and_lock(osa_adb_princ_t db, int locktype)
      case EINVAL:
 	  db->db = dbopen(db->filename, O_RDWR, 0600, DB_HASH, &db->info);
 	  if (db->db != NULL)
-	       return OSA_ADB_OK;
+	       goto open_ok;
      default:
 	  (void) osa_adb_release_lock(db);
 	  if (errno == EINVAL)
 	       return OSA_ADB_BAD_DB;
 	  return errno;
      }
+open_ok:
+     db->opencnt++;
+     return OSA_ADB_OK;
 }
 
 osa_adb_ret_t osa_adb_close_and_unlock(osa_adb_princ_t db)
 {
-     if(db->db->close(db->db) == -1) {
+     if (--db->opencnt)
+	  return osa_adb_release_lock(db);
+     if(db->db != NULL && db->db->close(db->db) == -1) {
 	  (void) osa_adb_release_lock(db);
 	  return OSA_ADB_FAILURE;
      }
@@ -400,4 +408,3 @@ osa_adb_ret_t osa_adb_close_and_unlock(osa_adb_princ_t db)
 
      return(osa_adb_release_lock(db));
 }
-
diff --git a/src/lib/kadm5/srv/server_init.c b/src/lib/kadm5/srv/server_init.c
index 31dd71a..f2cbc99 100644
--- a/src/lib/kadm5/srv/server_init.c
+++ b/src/lib/kadm5/srv/server_init.c
@@ -306,6 +306,34 @@ kadm5_ret_t kadm5_destroy(void *server_handle)
     return KADM5_OK;
 }
 
+kadm5_ret_t kadm5_lock(void *server_handle)
+{
+    kadm5_server_handle_t handle = server_handle;
+    kadm5_ret_t ret;
+
+    CHECK_HANDLE(server_handle);
+    ret = osa_adb_open_and_lock(handle->policy_db, OSA_ADB_EXCLUSIVE);
+    if (ret)
+	return ret;
+    ret = krb5_db_lock(handle->context, KRB5_LOCKMODE_EXCLUSIVE);
+    if (ret)
+	return ret;
+}
+
+kadm5_ret_t kadm5_unlock(void *server_handle)
+{
+    kadm5_server_handle_t handle = server_handle;
+    kadm5_ret_t ret;
+
+    CHECK_HANDLE(server_handle);
+    ret = osa_adb_close_and_unlock(handle->policy_db);
+    if (ret)
+	return ret;
+    ret = krb5_db_unlock(handle->context);
+    if (ret)
+	return ret;
+}
+
 kadm5_ret_t kadm5_flush(void *server_handle)
 {
      kadm5_server_handle_t handle = server_handle;