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xrdp/xrdpapi/xrdpapi.c

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/**
* xrdp: A Remote Desktop Protocol server.
*
* Copyright (C) Jay Sorg 2012-2013
* Copyright (C) Laxmikant Rashinkar 2012-2013
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#if defined(HAVE_CONFIG_H)
#include <config_ac.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <poll.h>
#include "log.h"
#include "xrdp_sockets.h"
#include "string_calls.h"
#include "xrdpapi.h"
struct wts_obj
{
int fd;
int display_num;
};
/* helper functions used by WTSxxx API - do not invoke directly */
static int
can_send(int sck, int millis, int restart);
static int
can_recv(int sck, int millis, int restart);
static int
mysend(int sck, const void *adata, int bytes);
static int
myrecv(int sck, void *adata, int bytes);
/*
* Opens a handle to the server end of a specified virtual channel - this
* call is deprecated - use WTSVirtualChannelOpenEx() instead
*
* @param hServer
* @param SessionId - current session ID; *must* be WTS_CURRENT_SERVER_HANDLE
* @param pVirtualName - virtual channel name when using SVC
* - name of endpoint listener when using DVC
*
* @return a valid pointer on success, NULL on error
******************************************************************************/
void *
WTSVirtualChannelOpen(void *hServer, unsigned int SessionId,
const char *pVirtualName)
{
if (hServer != WTS_CURRENT_SERVER_HANDLE)
{
return 0;
}
return WTSVirtualChannelOpenEx(SessionId, pVirtualName, 0);
}
/*
* Opens a handle to the server end of a specified virtual channel
*
* @param SessionId - current session ID; *must* be WTS_CURRENT_SERVER_HANDLE
* @param pVirtualName - virtual channel name when using SVC
* - name of endpoint listener when using DVC
* @param flags - type of channel and channel priority if DVC
*
* @return a valid pointer on success, NULL on error
******************************************************************************/
void *
WTSVirtualChannelOpenEx(unsigned int SessionId, const char *pVirtualName,
unsigned int flags)
{
struct wts_obj *wts;
int bytes;
unsigned long long1;
struct sockaddr_un s;
char *connect_data;
int chan_name_bytes;
int lerrno;
if (SessionId != WTS_CURRENT_SESSION)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: bad SessionId");
return 0;
}
wts = (struct wts_obj *) calloc(1, sizeof(struct wts_obj));
if (wts == NULL)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: calloc failed");
return 0;
}
wts->fd = -1;
wts->display_num = g_get_display_num_from_display(getenv("DISPLAY"));
if (wts->display_num < 0)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: fatal error; invalid DISPLAY");
free(wts);
return NULL;
}
/* we use unix domain socket to communicate with chansrv */
if ((wts->fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: socket failed");
free(wts);
return NULL;
}
/* set non blocking */
long1 = fcntl(wts->fd, F_GETFL);
long1 = long1 | O_NONBLOCK;
if (fcntl(wts->fd, F_SETFL, long1) < 0)
{
LOG(LOG_LEVEL_WARNING, "WTSVirtualChannelOpenEx: set non-block mode failed");
}
/* connect to chansrv session */
memset(&s, 0, sizeof(struct sockaddr_un));
s.sun_family = AF_UNIX;
bytes = sizeof(s.sun_path);
snprintf(s.sun_path, bytes - 1, CHANSRV_API_STR, getuid(), wts->display_num);
s.sun_path[bytes - 1] = 0;
bytes = sizeof(struct sockaddr_un);
if (connect(wts->fd, (struct sockaddr *) &s, bytes) < 0)
{
lerrno = errno;
if ((lerrno == EWOULDBLOCK) || (lerrno == EAGAIN) ||
(lerrno == EINPROGRESS))
{
/* ok */
}
else
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: connect failed");
free(wts);
return NULL;
}
}
/* wait for connection to complete */
if (!can_send(wts->fd, 500, 1))
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: can_send failed");
free(wts);
return NULL;
}
chan_name_bytes = strlen(pVirtualName);
bytes = 4 + 4 + 4 + chan_name_bytes + 4;
LOG_DEVEL(LOG_LEVEL_DEBUG,
"WTSVirtualChannelOpenEx: chan_name_bytes %d bytes %d pVirtualName %s",
chan_name_bytes, bytes, pVirtualName);
connect_data = (char *) calloc(bytes, 1);
if (connect_data == NULL)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: calloc failed");
free(wts);
return NULL;
}
connect_data[0] = (bytes >> 0) & 0xFF;
connect_data[1] = (bytes >> 8) & 0xFF;
connect_data[2] = (bytes >> 16) & 0xFF;
connect_data[3] = (bytes >> 24) & 0xFF;
/* version here(4-7), just leave 0 */
connect_data[8] = (chan_name_bytes >> 0) & 0xFF;
connect_data[9] = (chan_name_bytes >> 8) & 0xFF;
connect_data[10] = (chan_name_bytes >> 16) & 0xFF;
connect_data[11] = (chan_name_bytes >> 24) & 0xFF;
memcpy(connect_data + 12, pVirtualName, chan_name_bytes);
connect_data[4 + 4 + 4 + chan_name_bytes + 0] = (flags >> 0) & 0xFF;
connect_data[4 + 4 + 4 + chan_name_bytes + 1] = (flags >> 8) & 0xFF;
connect_data[4 + 4 + 4 + chan_name_bytes + 2] = (flags >> 16) & 0xFF;
connect_data[4 + 4 + 4 + chan_name_bytes + 3] = (flags >> 24) & 0xFF;
LOG_DEVEL(LOG_LEVEL_DEBUG,
"WTSVirtualChannelOpenEx: calling mysend with %d bytes", bytes);
if (mysend(wts->fd, connect_data, bytes) != bytes)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: mysend failed");
free(wts);
return NULL;
}
LOG_DEVEL(LOG_LEVEL_DEBUG, "WTSVirtualChannelOpenEx: sent ok");
if (!can_recv(wts->fd, 500, 1))
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: can_recv failed");
free(wts);
return NULL;
}
/* get response */
if (myrecv(wts->fd, connect_data, 4) != 4)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: myrecv failed");
free(wts);
return NULL;
}
if ((connect_data[0] != 0) || (connect_data[1] != 0) ||
(connect_data[2] != 0) || (connect_data[3] != 0))
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelOpenEx: connect_data not ok");
free(wts);
return NULL;
}
return wts;
}
/*
* Prevent receiving SIGPIPE on disconnect using either MSG_NOSIGNAL (Linux)
* or SO_NOSIGPIPE (Mac OS X)
*/
#if !defined(MSG_NOSIGNAL)
#define MSG_NOSIGNAL 0
#endif
/*****************************************************************************/
static int
mysend(int sck, const void *adata, int bytes)
{
int sent;
int error;
const char *data;
#if defined(SO_NOSIGPIPE)
const int on = 1;
setsockopt(sck, SOL_SOCKET, SO_NOSIGPIPE, &on, sizeof(on));
#endif
data = (const char *) adata;
sent = 0;
while (sent < bytes)
{
if (can_send(sck, 100, 0))
{
error = send(sck, data + sent, bytes - sent, MSG_NOSIGNAL);
if (error < 1)
{
return -1;
}
sent += error;
}
}
return sent;
}
/*****************************************************************************/
static int
myrecv(int sck, void *adata, int bytes)
{
int recd;
int error;
char *data;
#if defined(SO_NOSIGPIPE)
const int on = 1;
setsockopt(sck, SOL_SOCKET, SO_NOSIGPIPE, &on, sizeof(on));
#endif
data = (char *) adata;
recd = 0;
while (recd < bytes)
{
if (can_recv(sck, 100, 0))
{
error = recv(sck, data + recd, bytes - recd, MSG_NOSIGNAL);
if (error < 1)
{
return -1;
}
recd += error;
}
}
return recd;
}
/*
* write data to client connection
*
* @return 1 on success, 0 on error
*****************************************************************************/
int
WTSVirtualChannelWrite(void *hChannelHandle, const char *Buffer,
unsigned int Length, unsigned int *pBytesWritten)
{
struct wts_obj *wts;
int rv;
wts = (struct wts_obj *) hChannelHandle;
*pBytesWritten = 0;
if (wts == 0)
{
LOG(LOG_LEVEL_ERROR, "WTSVirtualChannelWrite: wts is NULL");
return 0;
}
if (!can_send(wts->fd, 0, 0))
{
return 1; /* can't write now, ok to try again */
}
rv = mysend(wts->fd, Buffer, Length);
LOG_DEVEL(LOG_LEVEL_DEBUG, "WTSVirtualChannelWrite: mysend() returned %d", rv);
if (rv >= 0)
{
/* success, but zero bytes may have been written */
*pBytesWritten = rv;
return 1;
}
/* fatal error */
return 0;
}
/*
* read data from a client connection
*
* @return 1 on success, 0 on error
*****************************************************************************/
int
WTSVirtualChannelRead(void *hChannelHandle, unsigned int TimeOut,
char *Buffer, unsigned int BufferSize,
unsigned int *pBytesRead)
{
struct wts_obj *wts;
int rv;
int lerrno;
wts = (struct wts_obj *)hChannelHandle;
if (wts == 0)
{
return 0;
}
if (can_recv(wts->fd, TimeOut, 0))
{
rv = recv(wts->fd, Buffer, BufferSize, 0);
if (rv == -1)
{
lerrno = errno;
if ((lerrno == EWOULDBLOCK) || (lerrno == EAGAIN) ||
(lerrno == EINPROGRESS))
{
*pBytesRead = 0;
return 1;
}
return 0;
}
else if (rv == 0)
{
return 0;
}
else if (rv > 0)
{
*pBytesRead = rv;
return 1;
}
}
*pBytesRead = 0;
return 1;
}
/*****************************************************************************/
int
WTSVirtualChannelClose(void *hChannelHandle)
{
struct wts_obj *wts;
wts = (struct wts_obj *)hChannelHandle;
if (wts == NULL)
{
return 0;
}
if (wts->fd != -1)
{
close(wts->fd);
}
free(wts);
return 1;
}
/*****************************************************************************/
int
WTSVirtualChannelQuery(void *hChannelHandle, WTS_VIRTUAL_CLASS WtsVirtualClass,
void **ppBuffer, unsigned int *pBytesReturned)
{
struct wts_obj *wts;
wts = (struct wts_obj *)hChannelHandle;
if (wts == NULL)
{
return 0;
}
if (WtsVirtualClass == WTSVirtualFileHandle)
{
*pBytesReturned = 4;
*ppBuffer = malloc(4);
if (*ppBuffer == NULL)
{
return 0;
}
memcpy(*ppBuffer, &(wts->fd), 4);
}
return 1;
}
/*****************************************************************************/
void
WTSFreeMemory(void *pMemory)
{
if (pMemory != NULL)
{
free(pMemory);
}
}
/*****************************************************************************
** **
** **
** Helper functions used by WTSxxx API - do not invoke directly **
** **
** **
*****************************************************************************/
/*
* check if socket is in a writable state - i.e will not block on write
*
* @param sck socket to check
* @param millis timeout value in milliseconds
* @param restart Try again if interrupted, even if this exceeds the timeout
*
* @return 0 if write will block
* @return 1 if write will not block
******************************************************************************/
static int
can_send(int sck, int millis, int restart)
{
int rv = 0;
struct pollfd pollfd;
int status;
pollfd.fd = sck;
pollfd.events = POLLOUT;
pollfd.revents = 0;
do
{
status = poll(&pollfd, 1, millis);
}
while (status < 0 && errno == EINTR && restart);
if (status > 0)
{
if ((pollfd.revents & POLLOUT) != 0)
{
rv = 1;
}
}
return rv;
}
/*****************************************************************************/
static int
can_recv(int sck, int millis, int restart)
{
int rv = 0;
struct pollfd pollfd;
int status;
pollfd.fd = sck;
pollfd.events = POLLIN;
pollfd.revents = 0;
do
{
status = poll(&pollfd, 1, millis);
}
while (status < 0 && errno == EINTR && restart);
if (status > 0)
{
if ((pollfd.revents & (POLLIN | POLLHUP)) != 0)
{
rv = 1;
}
}
return rv;
}
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