cdesktopenv/cde/programs/dtmail/libDtMail/Common/FileShare.C

568 lines
14 KiB
C

/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these libraries and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
/*
*+SNOTICE
*
*
* $TOG: FileShare.C /main/6 1999/03/26 16:52:00 mgreess $
*
* RESTRICTED CONFIDENTIAL INFORMATION:
*
* The information in this document is subject to special
* restrictions in a confidential disclosure agreement bertween
* HP, IBM, Sun, USL, SCO and Univel. Do not distribute this
* document outside HP, IBM, Sun, USL, SCO, or Univel wihtout
* Sun's specific written approval. This documment and all copies
* and derivative works thereof must be returned or destroyed at
* Sun's request.
*
* Copyright 1993 Sun Microsystems, Inc. All rights reserved.
*
*+ENOTICE
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <DtMail/FileShare.hh>
#include <DtMail/DtMailXtProc.h>
XtAppContext DtMailDamageContext = NULL;
static const int FileShareTimeout = 900000;
static int tlock_flag = 1;
static Tt_message msg_create(char *op, char *file, Tt_class tt_class, Tt_message_callback f)
{
Tt_message msg = tt_message_create();
// Create the tooltalk message
if (tt_ptr_error(msg) != TT_OK) {
return ((Tt_message) NULL);
}
/* Set the message class type */
if (tt_message_class_set (msg, tt_class) != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
/* Set the message address */
if (tt_message_address_set (msg, TT_PROCEDURE) != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
/* Set the disposition of the message */
if (tt_message_disposition_set (msg, TT_DISCARD) != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
/* Set the message operation. */
if (tt_message_op_set (msg, op) != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
/* Set the message scope */
if (tt_message_scope_set (msg, TT_FILE) != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
if (tt_message_file_set (msg, file) != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
if (tt_message_arg_add(msg, TT_IN, "DtMail", "lock") != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
if (f) {
if (tt_message_callback_add(msg, f) != TT_OK) {
tt_message_destroy(msg);
return ((Tt_message) NULL);
}
}
return (msg);
}
Tt_callback_action
FileShare::mt_lock_cb(Tt_message m, Tt_pattern p)
{
Tt_state state = tt_message_state(m);
char *op;
char *flag = NULL;
op = tt_message_op(m);
if (!op) {
return TT_CALLBACK_CONTINUE;
}
flag = tt_message_arg_val(m, 0);
if (!strcmp(op, "tlock")) {
// handle tlock request
if (state == TT_HANDLED) {
tlock_flag = -1;
tt_message_destroy(m);
} else if (state == TT_FAILED) {
tlock_flag = 0;
tt_message_destroy(m);
} else if (state == TT_SENT) {
if (tt_ptr_error(flag) == TT_OK) {
// this message is from another dtmail, ignore it
return TT_CALLBACK_CONTINUE;
}
tt_message_reply(m);
}
} else if (!strcmp(op, "rulock")) {
// handle rulock notice
if (state == TT_SENT) {
DtMailBoolean answer = DTM_FALSE; // default is to not give up the lock
FileShare *f = (FileShare *)tt_pattern_user(p, 1);
if (f->_cb_func)
{
char *msg =
DtMailEnv::getMessageText(
FileShareMsgSet, 5,
"Another user would like your lock.");
answer = f->_cb_func(DTMC_UNLOCK, f->_path, msg, f->_cb_data);
}
tt_message_destroy(m);
}
}
tt_free(op);
return TT_CALLBACK_PROCESSED;
}
FileShare::FileShare(DtMailEnv & error,
DtMail::Session * session,
const char * path,
DtMailCallback cb,
void * clientData)
{
DtMail::MailRc *mailrc = session->mailRc(error);
_key = session->newObjectKey();
_session = session;
_path = strdup(path);
_cb_func = cb;
_cb_data = clientData;
// For now, assume we can't write to the file.
//
_have_write_access = DTM_FALSE;
_other_modified = DTM_TRUE;
_mt_pattern = NULL;
error.clear();
// Register the file pattern.
//
_tt_handle = new TTHandle;
_tt_handle->session = _session;
_tt_handle->key = _key;
_tt_handle->self = this;
_file_pats = ttdt_file_join(_path, TT_FILE, 0, fileCB, _tt_handle);
if (tt_pointer_error(_file_pats) != TT_OK) {
error.setError(DTME_TTFailure);
_file_pats = NULL;
return;
}
// isModified(error);
}
FileShare::~FileShare(void)
{
if (_have_write_access == DTM_TRUE && _file_pats) {
_pending = PENDING_DESTROY;
// ttdt_file_event(NULL, TTDT_SAVED, _file_pats, 1);
_session->removeObjectKey(_key);
}
if (NULL != _tt_handle)
delete _tt_handle;
if (_file_pats) {
ttdt_file_quit(_file_pats, 1);
}
if (_mt_pattern) {
tt_pattern_destroy(_mt_pattern);
_mt_pattern = NULL;
}
if (_path) {
free(_path);
}
_have_write_access = DTM_FALSE;
_file_pats = NULL;
}
DtMailBoolean
FileShare::isModified(DtMailEnv & error)
{
error.clear();
if (!_path) {
return(DTM_FALSE);
}
DtMailBoolean answer = DTM_FALSE;
Tt_message mt_msg;
mt_msg = msg_create("tlock", _path, TT_REQUEST, mt_lock_cb);
if (mt_msg == NULL) {
error.setError(DTME_TTFailure);
return DTM_TRUE;
}
if (tt_message_send(mt_msg) != TT_OK) {
error.setError(DTME_TTFailure);
return DTM_TRUE;
}
tttk_block_while((XtAppContext)0, &tlock_flag, FileShareTimeout);
// mt_lock_cb sets tlock_flag to -1 if mbox is locked
if (tlock_flag == -1) {
tlock_flag = 1; // reset the tlock_flag
_other_modified = DTM_TRUE;
_mt_lock = DTM_TRUE;
return DTM_TRUE;
} else {
// else tlock_flag == 0, means no lock on this mbox
// or tlock_flag == 1, means time out
tlock_flag = 1; // reset the tlock_flag
_mt_lock = DTM_FALSE;
// now let's try the dtmail protocol
if (ttdt_Get_Modified(NULL, _path, TT_FILE, NULL, FileShareTimeout)) {
answer = DTM_TRUE;
_other_modified = DTM_TRUE;
} else {
answer = DTM_FALSE;
_other_modified = DTM_FALSE;
}
return(answer);
}
}
void
FileShare::lockFile(DtMailEnv & error)
{
int always;
error.clear();
// If we have the access, then we locked it before. Simply return.
//
if (_have_write_access == DTM_TRUE) {
return;
}
// First step in locking is determining if anyone else has the lock.
// If they do, then we need to ask them to save their changes and
// exit.
//
if (isModified(error) == DTM_TRUE) {
DtMailBoolean take_lock = DTM_FALSE; // default is to not request access
// calls syncViewAndStoreCallback which then calls syncViewAndStore
if (_cb_func)
{
char *msg =
DtMailEnv::getMessageText(
FileShareMsgSet, 6,
"Another session has this mailbox locked. Request access?");
take_lock = _cb_func(DTMC_QUERYLOCK, _path, msg, _cb_data);
}
if (take_lock == DTM_FALSE) {
error.setError(DTME_OtherOwnsWrite);
return;
}
// isModified sets _mt_lock to DTM_TRUE is the mailbox is locked
// by mailtool
if (_mt_lock == DTM_TRUE) {
// mailtool style locking
Tt_message mt_msg;
mt_msg = msg_create("rulock", _path, TT_NOTICE, NULL);
if (mt_msg == NULL) {
error.setError(DTME_TTFailure);
return;
}
if (tt_message_send(mt_msg) != TT_OK) {
error.setError(DTME_TTFailure);
return;
}
tt_message_destroy(mt_msg);
} else {
// ttdt style locking
ttdt_Save(NULL, _path, TT_FILE, DtMailDamageContext, FileShareTimeout);
}
// Give the other mailer FileShareTimeout seconds to give up the lock
time_t t_start;
time(&t_start);
while (1) {
sleep(5);
if (isModified(error) == DTM_FALSE) {
break;
} else {
if (time(NULL) - t_start > FileShareTimeout) {
// time out!
error.setError(DTME_OtherOwnsWrite);
return;
}
}
}
}
// Set this so we don't call our client during this handshake.
//
_pending = PENDING_LOCK;
_outstanding = DTM_TRUE;
// Now we are ready to lock the mailbox
// register this pattern so we can handle messages from mailtool
_mt_pattern = tt_pattern_create();
tt_pattern_category_set(_mt_pattern, TT_HANDLE);
tt_pattern_scope_add(_mt_pattern, TT_FILE);
tt_pattern_file_add(_mt_pattern, _path);
tt_pattern_op_add(_mt_pattern, "tlock");
tt_pattern_op_add(_mt_pattern, "rulock");
tt_pattern_callback_add(_mt_pattern, mt_lock_cb);
tt_pattern_user_set(_mt_pattern, 1, (void *)this);
if (tt_pattern_register(_mt_pattern) != TT_OK) {
error.setError(DTME_TTFailure);
return;
}
// Send the message saying we want to be the owner.
ttdt_file_event(NULL, TTDT_MODIFIED, _file_pats, 1);
// We need to process any messages that have arrived. We will get our own
// modified message, which is not terribly interesting. What is interesting
// is a modified message from someone else. That means that we have a race
// condition where two processes both asked if the file was being modified,
// and it wasn't. Then both said they were the owner, which is obviously
// wrong so we need to blow both off and make them try again. Hopefully
// there is enough randomness in our clients that the race condition will
// clear itself up and we won't get here very often.
//
always = 1;
while(_outstanding == DTM_TRUE) {
tttk_block_while((XtAppContext)0, &always, 0);
}
if (_other_modified == DTM_TRUE) {
// Well, we have a race. Fail this lock as will the other process,
// we hope.
error.setError(DTME_OtherOwnsWrite);
return;
}
// Okay, we now have the lock.
_have_write_access = DTM_TRUE;
}
DtMailBoolean
FileShare::readOnly(DtMailEnv & error)
{
DtMailBoolean answer = DTM_TRUE; // default is to accept read-only access
if (_cb_func)
{
char *msg =
DtMailEnv::getMessageText(
FileShareMsgSet, 7,
"Unable to obtain lock, open this mailbox as read only?");
answer = _cb_func(DTMC_READONLY, _path, msg, _cb_data);
}
if (answer)
error.clear();
return(answer);
}
DtMailBoolean
FileShare::readWriteOverride(DtMailEnv & error)
{
DtMailBoolean answer = DTM_FALSE; // default is to open for read-only access
if (_cb_func)
{
char *msg =
DtMailEnv::getMessageText(
FileShareMsgSet, 8,
"Unable to obtain lock because system not responding, open this mailbox as read only, read write, or cancel?");
answer = _cb_func(DTMC_READWRITEOVERRIDE, _path, msg, _cb_data);
}
if (answer == ((DtMailBoolean)((DTM_FALSE+DTM_TRUE)*2))) {
error.setError(DTME_UserInterrupted);
answer = DTM_FALSE;
}
else {
error.clear();
}
return(answer);
}
Tt_message
FileShare::fileCB(Tt_message msg,
Tttk_op op,
char * path,
void *clientData,
int,
int same_proc)
{
TTHandle *tt_handle = (TTHandle *)clientData;
DtMailBoolean answer;
if (tt_handle->session->validObjectKey(tt_handle->key) == DTM_FALSE) {
// This object has been destroyed. We got here most likely because
// ToolTalk is responding to one of our clean up messages. In any
// case, fail the message and return.
//
tttk_message_fail(msg, TT_DESKTOP_ECANCELED, "Object destroyed", 1);
return(0);
}
FileShare * self = tt_handle->self;
switch(op) {
case TTDT_MODIFIED:
if (self->_outstanding == DTM_FALSE && !same_proc) {
if (self->_cb_func)
{
char *msg =
DtMailEnv::getMessageText(
FileShareMsgSet, 9,
"Another user has taken your lock.");
self->_cb_func(DTMC_LOSTLOCK, path, msg, self->_cb_data);
}
self->_other_modified = DTM_TRUE;
self->_have_write_access = DTM_FALSE;
break;
}
if (self->_outstanding == DTM_TRUE && self->_pending == PENDING_LOCK) {
// This could be one of 2 conditions. If the message is
// from us, then we have the lock, and we are done.
// If not, then someone else is asking for the lock. We
// reflect this by giving them the lock.
//
if (same_proc) {
self->_other_modified = DTM_FALSE;
self->_have_write_access = DTM_TRUE;
self->_outstanding = DTM_FALSE;
}
else {
self->_other_modified = DTM_TRUE;
self->_have_write_access = DTM_FALSE;
// We haven't seen our own request yet. Leave outstanding
// so we can process it before leaving.
}
}
break;
case TTDT_GET_MODIFIED:
tt_message_arg_ival_set(msg, 1, 1);
tt_message_reply(msg);
break;
case TTDT_SAVED:
case TTDT_REVERTED:
// The other process has saved their changes (or tossed them).
// At this point we should be able to start modifying the file.
//
self->_other_modified = DTM_FALSE;
if (self->_outstanding == DTM_TRUE && self->_pending == PENDING_SAVE) {
self->_outstanding = DTM_FALSE;
}
break;
case TTDT_REVERT:
case TTDT_SAVE:
// Someone is asking us to save our changes and close the file.
//
answer = DTM_FALSE; // default is to not give up the lock
if (self->_cb_func)
{
char *msg =
DtMailEnv::getMessageText(
FileShareMsgSet, 5,
"Another user would like your lock.");
answer = self->_cb_func(DTMC_UNLOCK, path, msg, self->_cb_data);
}
if (answer == DTM_TRUE) {
tt_message_reply(msg);
} else {
tttk_message_fail(msg, TT_DESKTOP_EACCES, 0, 0);
}
break;
default:
// Other messages, we simply smile and say thank you.:-)
//
tt_message_reply(msg);
break;
}
tt_message_destroy(msg);
return(0);
}