/**
* @brief Retrieve keys in an atomic and universal way.
*
* @pre The @p handle must be passed as returned from kdbOpen().
*
* @pre The @p returned KeySet must be a valid KeySet, e.g. constructed
* with ksNew().
*
* @pre The @p parentKey Key must be a valid Key, e.g. constructed with
* keyNew().
*
* If you pass NULL on any parameter kdbGet() will fail immediately without doing anything.
*
* The @p returned KeySet may already contain some keys, e.g. from previous
* kdbGet() calls. The new retrieved keys will be appended using
* ksAppendKey().
*
* If not done earlier kdbGet() will fully retrieve all keys under the @p parentKey
* folder recursively (See Optimization below when it will not be done).
*
* @note kdbGet() might retrieve more keys than requested (that are not
* below parentKey). These keys must be passed to calls of kdbSet(),
* otherwise they will be lost. This stems from the fact that the
* user has the only copy of the whole configuration and backends
* only write configuration that was passed to them.
* For example, if you kdbGet() "system/mountpoint/interest"
* you will not only get all keys below system/mountpoint/interest,
* but also all keys below system/mountpoint (if system/mountpoint
* is a mountpoint as the name suggests, but
* system/mountpoint/interest is not a mountpoint).
* Make sure to not touch or remove keys outside the keys of interest,
* because others may need them!
*
* @par Example:
* This example demonstrates the typical usecase within an application
* (without error handling).
*
* @include kdbget.c
*
* When a backend fails kdbGet() will return -1 with all
* error and warning information in the @p parentKey.
* The parameter @p returned will not be changed.
*
* @par Optimization:
* In the first run of kdbGet all requested (or more) keys are retrieved. On subsequent
* calls only the keys are retrieved where something was changed
* inside the key database. The other keys stay in the
* KeySet returned as passed.
*
* It is your responsibility to save the original keyset if you
* need it afterwards.
*
* If you want to be sure to get a fresh keyset again, you need to open a
* second handle to the key database using kdbOpen().
*
* @param handle contains internal information of @link kdbOpen() opened @endlink key database
* @param parentKey is used to add warnings and set an error
* information. Additionally, its name is a hint which keys
* should be retrieved (it is possible that more are retrieved, see Note above).
* - cascading keys (starting with /) will retrieve the same path in all namespaces
* - / will retrieve all keys
* @param ks the (pre-initialized) KeySet returned with all keys found
* will not be changed on error or if no update is required
* @see ksLookup(), ksLookupByName() for powerful
* lookups after the KeySet was retrieved
* @see kdbOpen() which needs to be called before
* @see kdbSet() to save the configuration afterwards and kdbClose() to
* finish affairs with the key database.
* @retval 1 if the keys were retrieved successfully
* @retval 0 if there was no update - no changes are made to the keyset then
* @retval -1 on failure - no changes are made to the keyset then
* @ingroup kdb
*/
int kdbGet (KDB * handle, KeySet * ks, Key * parentKey)
{
elektraNamespace ns = keyGetNamespace (parentKey);
if (ns == KEY_NS_NONE)
{
return -1;
}
Key * oldError = keyNew (keyName (parentKey), KEY_END);
copyError (oldError, parentKey);
if (ns == KEY_NS_META)
{
clearError (parentKey);
keyDel (oldError);
ELEKTRA_SET_ERRORF (104, parentKey, "metakey with name \"%s\" passed to kdbGet", keyName (parentKey));
return -1;
}
if (ns == KEY_NS_EMPTY)
{
ELEKTRA_ADD_WARNING (105, parentKey, "invalid key name passed to kdbGet");
}
int errnosave = errno;
Key * initialParent = keyDup (parentKey);
ELEKTRA_LOG ("now in new kdbGet (%s)", keyName (parentKey));
Split * split = splitNew ();
if (!handle || !ks)
{
clearError (parentKey);
ELEKTRA_SET_ERROR (37, parentKey, "handle or ks null pointer");
goto error;
}
elektraGlobalGet (handle, ks, parentKey, PREGETSTORAGE, INIT);
elektraGlobalGet (handle, ks, parentKey, PREGETSTORAGE, MAXONCE);
elektraGlobalGet (handle, ks, parentKey, PREGETSTORAGE, DEINIT);
if (splitBuildup (split, handle, parentKey) == -1)
{
clearError (parentKey);
ELEKTRA_SET_ERROR (38, parentKey, "error in splitBuildup");
goto error;
}
// Check if a update is needed at all
switch (elektraGetCheckUpdateNeeded (split, parentKey))
{
case 0: // We don't need an update so let's do nothing
keySetName (parentKey, keyName (initialParent));
elektraGlobalGet (handle, ks, parentKey, POSTGETSTORAGE, INIT);
elektraGlobalGet (handle, ks, parentKey, POSTGETSTORAGE, MAXONCE);
elektraGlobalGet (handle, ks, parentKey, POSTGETSTORAGE, DEINIT);
splitUpdateFileName (split, handle, parentKey);
keyDel (initialParent);
splitDel (split);
errno = errnosave;
keyDel (oldError);
return 0;
case -1:
goto error;
// otherwise fall trough
}
// Appoint keys (some in the bypass)
if (splitAppoint (split, handle, ks) == -1)
{
clearError (parentKey);
ELEKTRA_SET_ERROR (38, parentKey, "error in splitAppoint");
goto error;
}
if (handle->globalPlugins[POSTGETSTORAGE][FOREACH] || handle->globalPlugins[POSTGETCLEANUP][FOREACH])
{
clearError (parentKey);
if (elektraGetDoUpdateWithGlobalHooks (NULL, split, NULL, parentKey, initialParent, FIRST) == -1)
{
goto error;
}
else
{
copyError (parentKey, oldError);
}
keySetName (parentKey, keyName (initialParent));
if (splitGet (split, parentKey, handle) == -1)
{
ELEKTRA_ADD_WARNING (108, parentKey, keyName (ksCurrent (ks)));
// continue, because sizes are already updated
}
ksClear (ks);
splitMerge (split, ks);
clearError (parentKey);
if (elektraGetDoUpdateWithGlobalHooks (handle, split, ks, parentKey, initialParent, LAST) == -1)
{
goto error;
}
else
{
copyError (parentKey, oldError);
}
}
else
{
/* Now do the real updating,
but not for bypassed keys in split->size-1 */
clearError (parentKey);
if (elektraGetDoUpdate (split, parentKey) == -1)
{
goto error;
}
else
{
copyError (parentKey, oldError);
}
/* Now post-process the updated keysets */
if (splitGet (split, parentKey, handle) == -1)
{
ELEKTRA_ADD_WARNING (108, parentKey, keyName (ksCurrent (ks)));
// continue, because sizes are already updated
}
/* We are finished, now just merge everything to returned */
ksClear (ks);
splitMerge (split, ks);
}
elektraGlobalGet (handle, ks, parentKey, POSTGETSTORAGE, INIT);
elektraGlobalGet (handle, ks, parentKey, POSTGETSTORAGE, MAXONCE);
elektraGlobalGet (handle, ks, parentKey, POSTGETSTORAGE, DEINIT);
ksRewind (ks);
keySetName (parentKey, keyName (initialParent));
splitUpdateFileName (split, handle, parentKey);
keyDel (initialParent);
keyDel (oldError);
splitDel (split);
errno = errnosave;
return 1;
error:
keySetName (parentKey, keyName (initialParent));
elektraGlobalError (handle, ks, parentKey, POSTGETSTORAGE, INIT);
elektraGlobalError (handle, ks, parentKey, POSTGETSTORAGE, MAXONCE);
elektraGlobalError (handle, ks, parentKey, POSTGETSTORAGE, DEINIT);
keySetName (parentKey, keyName (initialParent));
if (handle) splitUpdateFileName (split, handle, parentKey);
keyDel (initialParent);
keyDel (oldError);
splitDel (split);
errno = errnosave;
return -1;
}
/*
* Copy a file with path srcName to a file with name newName.
* If the destination already exists, the operation fails.
* Links are followed.
* Special files (fifos, char devices, block devices, etc) will be
* read as long as there is data available and the destination will be
* a regular file with that data.
* The new file will have the same permissions as the old.
* If an error occurs during copying, an attempt will be made to
* remove the copy.
*/
int
copyFile (uio_DirHandle *srcDir, const char *srcName,
uio_DirHandle *dstDir, const char *newName)
{
uio_Handle *src, *dst;
struct stat sb;
#define BUFSIZE 65536
uint8 *buf, *bufPtr;
ssize_t numInBuf, numWritten;
src = uio_open (srcDir, srcName, O_RDONLY
#ifdef WIN32
| O_BINARY
#endif
, 0);
if (src == NULL)
return -1;
if (uio_fstat (src, &sb) == -1)
return copyError (src, NULL, NULL, NULL, NULL);
dst = uio_open (dstDir, newName, O_WRONLY | O_CREAT | O_EXCL
#ifdef WIN32
| O_BINARY
#endif
, sb.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO));
if (dst == NULL)
return copyError (src, NULL, NULL, NULL, NULL);
buf = HMalloc(BUFSIZE);
// This was originally a statically allocated buffer,
// but as this function might be run from a thread with
// a small Stack, this is better.
while (1)
{
numInBuf = uio_read (src, buf, BUFSIZE);
if (numInBuf == -1)
{
if (errno == EINTR)
continue;
return copyError (src, dst, dstDir, newName, buf);
}
if (numInBuf == 0)
break;
bufPtr = buf;
do
{
numWritten = uio_write (dst, bufPtr, numInBuf);
if (numWritten == -1)
{
if (errno == EINTR)
continue;
return copyError (src, dst, dstDir, newName, buf);
}
numInBuf -= numWritten;
bufPtr += numWritten;
} while (numInBuf > 0);
}
HFree (buf);
uio_close (src);
uio_close (dst);
errno = 0;
return 0;
}
/** @brief Set keys in an atomic and universal way.
*
* @pre kdbGet() must be called before kdbSet():
* - initially (after kdbOpen())
* - after conflict errors in kdbSet().
*
* @pre The @p returned KeySet must be a valid KeySet, e.g. constructed
* with ksNew().
*
* @pre The @p parentKey Key must be a valid Key, e.g. constructed with
* keyNew().
*
* If you pass NULL on any parameter kdbSet() will fail immediately without doing anything.
*
* With @p parentKey you can give an hint which part of the given keyset
* is of interest for you. Then you promise to only modify or
* remove keys below this key. All others would be passed back
* as they were retrieved by kdbGet().
*
* @par Errors
* If some error occurs:
* - kdbSet() will leave the KeySet's * internal cursor on the key that generated the error.
* - Error information will be written into the metadata of
* the parent key.
* - None of the keys are actually committed in this situation, i.e. no
* configuration file will be modified.
*
* In case of errors you should present the error message to the user and let the user decide what
* to do. Possible solutions are:
* - remove the problematic key and use kdbSet() again (for validation or type errors)
* - change the value of the problematic key and use kdbSet() again (for validation errors)
* - do a kdbGet() (for conflicts, i.e. error 30) and then
* - set the same keyset again (in favour of what was set by this user)
* - drop the old keyset (in favour of what was set from another application)
* - merge the original, your own and the other keyset
* - export the configuration into a file (for unresolvable errors)
* - repeat the same kdbSet might be of limited use if the user does
* not explicitly request it, because temporary
* errors are rare and its unlikely that they fix themselves
* (e.g. disc full, permission problems)
*
* @par Optimization
* Each key is checked with keyNeedSync() before being actually committed.
* If no key of a backend needs to be synced
* any affairs to backends are omitted and 0 is returned.
*
* @snippet kdbset.c set
*
* showElektraErrorDialog() and doElektraMerge() need to be implemented
* by the user of Elektra. For doElektraMerge a 3-way merge algorithm exists in
* libelektra-tools.
*
* @param handle contains internal information of @link kdbOpen() opened @endlink key database
* @param ks a KeySet which should contain changed keys, otherwise nothing is done
* @param parentKey is used to add warnings and set an error
* information. Additionally, its name is an hint which keys
* should be committed (it is possible that more are changed).
* - cascading keys (starting with /) will set the path in all namespaces
* - / will commit all keys
* - metanames will be rejected (error 104)
* - empty/invalid (error 105)
* @retval 1 on success
* @retval 0 if nothing had to be done, no changes in KDB
* @retval -1 on failure, no changes in KDB
* @see keyNeedSync()
* @see ksCurrent() contains the error key
* @see kdbOpen() and kdbGet() that must be called first
* @see kdbClose() that must be called afterwards
* @ingroup kdb
*/
int kdbSet (KDB * handle, KeySet * ks, Key * parentKey)
{
elektraNamespace ns = keyGetNamespace (parentKey);
if (ns == KEY_NS_NONE)
{
return -1;
}
Key * oldError = keyNew (keyName (parentKey), KEY_END);
copyError (oldError, parentKey);
if (ns == KEY_NS_META)
{
clearError (parentKey); // clear previous error to set new one
ELEKTRA_SET_ERRORF (104, parentKey, "metakey with name \"%s\" passed to kdbSet", keyName (parentKey));
keyDel (oldError);
return -1;
}
if (ns == KEY_NS_EMPTY)
{
ELEKTRA_ADD_WARNING (105, parentKey, "invalid key name passed to kdbSet");
}
if (!handle || !ks)
{
clearError (parentKey); // clear previous error to set new one
ELEKTRA_SET_ERROR (37, parentKey, "handle or ks null pointer");
keyDel (oldError);
return -1;
}
int errnosave = errno;
Key * initialParent = keyDup (parentKey);
ELEKTRA_LOG ("now in new kdbSet (%s) %p %zd", keyName (parentKey), (void *)handle, ksGetSize (ks));
elektraGlobalSet (handle, ks, parentKey, PRESETSTORAGE, INIT);
elektraGlobalSet (handle, ks, parentKey, PRESETSTORAGE, MAXONCE);
elektraGlobalSet (handle, ks, parentKey, PRESETSTORAGE, DEINIT);
ELEKTRA_LOG ("after presetstorage maxonce(%s) %p %zd", keyName (parentKey), (void *)handle, ksGetSize (ks));
Split * split = splitNew ();
Key * errorKey = 0;
if (splitBuildup (split, handle, parentKey) == -1)
{
clearError (parentKey); // clear previous error to set new one
ELEKTRA_SET_ERROR (38, parentKey, "error in splitBuildup");
goto error;
}
// 1.) Search for syncbits
int syncstate = splitDivide (split, handle, ks);
if (syncstate == -1)
{
clearError (parentKey); // clear previous error to set new one
ELEKTRA_SET_ERROR (8, parentKey, keyName (ksCurrent (ks)));
goto error;
}
ELEKTRA_ASSERT (syncstate == 0 || syncstate == 1, "syncstate not 0 or 1, but %d", syncstate);
// 2.) Search for changed sizes
syncstate |= splitSync (split);
ELEKTRA_ASSERT (syncstate <= 1, "syncstate not equal or below 1, but %d", syncstate);
if (syncstate != 1)
{
/* No update is needed */
keySetName (parentKey, keyName (initialParent));
if (syncstate < 0) clearError (parentKey); // clear previous error to set new one
if (syncstate == -1)
{
ELEKTRA_SET_ERROR (107, parentKey, "Assert failed: invalid namespace");
}
else if (syncstate < -1)
{
ELEKTRA_SET_ERROR (107, parentKey, keyName (split->parents[-syncstate - 2]));
}
keyDel (initialParent);
splitDel (split);
errno = errnosave;
keyDel (oldError);
return syncstate == 0 ? 0 : -1;
}
ELEKTRA_ASSERT (syncstate == 1, "syncstate not 1, but %d", syncstate);
splitPrepare (split);
clearError (parentKey); // clear previous error to set new one
if (elektraSetPrepare (split, parentKey, &errorKey, handle->globalPlugins) == -1)
{
goto error;
}
else
{
// no error, restore old error
copyError (parentKey, oldError);
}
keySetName (parentKey, keyName (initialParent));
elektraGlobalSet (handle, ks, parentKey, PRECOMMIT, INIT);
elektraGlobalSet (handle, ks, parentKey, PRECOMMIT, MAXONCE);
elektraGlobalSet (handle, ks, parentKey, PRECOMMIT, DEINIT);
elektraSetCommit (split, parentKey);
elektraGlobalSet (handle, ks, parentKey, COMMIT, INIT);
elektraGlobalSet (handle, ks, parentKey, COMMIT, MAXONCE);
elektraGlobalSet (handle, ks, parentKey, COMMIT, DEINIT);
splitUpdateSize (split);
keySetName (parentKey, keyName (initialParent));
elektraGlobalSet (handle, ks, parentKey, POSTCOMMIT, INIT);
elektraGlobalSet (handle, ks, parentKey, POSTCOMMIT, MAXONCE);
elektraGlobalSet (handle, ks, parentKey, POSTCOMMIT, DEINIT);
for (size_t i = 0; i < ks->size; ++i)
{
// remove all flags from all keys
clear_bit (ks->array[i]->flags, KEY_FLAG_SYNC);
}
keySetName (parentKey, keyName (initialParent));
keyDel (initialParent);
splitDel (split);
keyDel (oldError);
errno = errnosave;
return 1;
error:
keySetName (parentKey, keyName (initialParent));
elektraGlobalError (handle, ks, parentKey, PREROLLBACK, INIT);
elektraGlobalError (handle, ks, parentKey, PREROLLBACK, MAXONCE);
elektraGlobalError (handle, ks, parentKey, PREROLLBACK, DEINIT);
elektraSetRollback (split, parentKey);
if (errorKey)
{
Key * found = ksLookup (ks, errorKey, 0);
if (!found)
{
ELEKTRA_ADD_WARNING (82, parentKey, keyName (errorKey));
}
}
keySetName (parentKey, keyName (initialParent));
elektraGlobalError (handle, ks, parentKey, POSTROLLBACK, INIT);
elektraGlobalError (handle, ks, parentKey, POSTROLLBACK, MAXONCE);
elektraGlobalError (handle, ks, parentKey, POSTROLLBACK, DEINIT);
keySetName (parentKey, keyName (initialParent));
keyDel (initialParent);
splitDel (split);
errno = errnosave;
keyDel (oldError);
return -1;
}
