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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.
*/
#define LOG_LEVEL 1
#define LLOG(_level, _args) \
do { if (_level < LOG_LEVEL) { ErrorF _args ; } } while (0)
#define LLOGLN(_level, _args) \
do { if (_level < LOG_LEVEL) { printf _args ; printf("\n"); } } while (0)
#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 "xrdpapi.h"
struct wts_obj
{
int fd;
int status;
char name[9];
char dname[128];
int display_num;
uint32_t flags;
};
/* helper functions used by WTSxxx API - do not invoke directly */
static int get_display_num_from_display(char *display_text);
static int send_init(struct wts_obj *wts);
static int can_send(int sck, int millis);
static int can_recv(int sck, int millis);
static char g_xrdpapi_magic[12] =
{ 0x78, 0x32, 0x10, 0x67, 0x00, 0x92, 0x30, 0x56, 0xff, 0xd8, 0xa9, 0x1f };
/*
* 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;
char *display_text;
int bytes;
unsigned long llong;
struct sockaddr_un s;
if (SessionId != WTS_CURRENT_SESSION)
{
LLOGLN(0, ("WTSVirtualChannelOpenEx: bad SessionId"));
return 0;
}
wts = (struct wts_obj *) calloc(1, sizeof(struct wts_obj));
wts->fd = -1;
wts->flags = flags;
display_text = getenv("DISPLAY");
if (display_text != 0)
{
wts->display_num = get_display_num_from_display(display_text);
}
if (wts->display_num <= 0)
{
LLOGLN(0, ("WTSVirtualChannelOpenEx: fatal error; display is 0"));
free(wts);
return NULL;
}
/* we use unix domain socket to communicate with chansrv */
if ((wts->fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
{
free(wts);
return NULL;
}
/* set non blocking */
llong = fcntl(wts->fd, F_GETFL);
llong = llong | O_NONBLOCK;
if (fcntl(wts->fd, F_SETFL, llong) < 0)
{
LLOGLN(10, ("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, "/tmp/.xrdp/xrdpapi_%d", wts->display_num);
s.sun_path[bytes - 1] = 0;
bytes = sizeof(struct sockaddr_un);
if (connect(wts->fd, (struct sockaddr *) &s, bytes) == 0)
{
LLOGLN(10, ("WTSVirtualChannelOpenEx: connected ok, name %s", pVirtualName));
strncpy(wts->name, pVirtualName, 8);
/* wait for connection to complete and send init */
if (send_init(wts) == 0)
{
/* all ok */
wts->status = 1;
}
}
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))
{
error = send(sck, data + sent, bytes - sent, MSG_NOSIGNAL);
if (error < 1)
{
return -1;
}
sent += error;
}
}
return sent;
}
/*
* write data to client connection
*
* @return 0 on success, -1 on error
*****************************************************************************/
int
WTSVirtualChannelWrite(void *hChannelHandle, const char *Buffer,
unsigned int Length, unsigned int *pBytesWritten)
{
struct wts_obj *wts;
int rv;
int header[4];
wts = (struct wts_obj *) hChannelHandle;
*pBytesWritten = 0;
if (wts == 0)
{
LLOGLN(10, ("WTSVirtualChannelWrite: wts is NULL"));
return -1;
}
if (wts->status != 1)
{
LLOGLN(10, ("WTSVirtualChannelWrite: wts->status != 1"));
return -1;
}
if (!can_send(wts->fd, 0))
{
return 0; /* can't write now, ok to try again */
}
rv = 0;
memcpy(header, g_xrdpapi_magic, 12);
header[3] = Length;
if (mysend(wts->fd, header, 16) == 16)
{
rv = mysend(wts->fd, Buffer, Length);
}
else
{
LLOGLN(0, ("WTSVirtualChannelWrite: header write failed"));
return -1;
}
LLOGLN(10, ("WTSVirtualChannelWrite: mysend() returned %d", rv));
if (rv >= 0)
{
/* success, but zero bytes may have been written */
*pBytesWritten = rv;
return 0;
}
#if 0 /* coverity: this is dead code */
/* error, but is it ok to try again? */
if ((rv == EWOULDBLOCK) || (rv == EAGAIN) || (rv == EINPROGRESS))
{
return 0; /* failed to send, but should try again */
}
#endif
/* fatal error */
return -1;
}
/*****************************************************************************/
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 (wts->status != 1)
{
return 0;
}
if (can_recv(wts->fd, TimeOut))
{
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 == 0)
{
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 == 0)
{
return 0;
}
if (wts->status != 1)
{
return 0;
}
if (WtsVirtualClass == WTSVirtualFileHandle)
{
*pBytesReturned = 4;
*ppBuffer = malloc(4);
memcpy(*ppBuffer, &(wts->fd), 4);
}
return 1;
}
/*****************************************************************************/
void
WTSFreeMemory(void *pMemory)
{
if (pMemory != 0)
{
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
*
* @return 0 if write will block
* @return 1 if write will not block
******************************************************************************/
static int
can_send(int sck, int millis)
{
struct timeval time;
fd_set wfds;
int select_rv;
/* setup for a select call */
FD_ZERO(&wfds);
FD_SET(sck, &wfds);
time.tv_sec = millis / 1000;
time.tv_usec = (millis * 1000) % 1000000;
/* check if it is ok to write to specified socket */
select_rv = select(sck + 1, 0, &wfds, 0, &time);
return (select_rv > 0) ? 1 : 0;
}
/*****************************************************************************/
static int
can_recv(int sck, int millis)
{
struct timeval time;
fd_set rfds;
int select_rv;
FD_ZERO(&rfds);
FD_SET(sck, &rfds);
time.tv_sec = millis / 1000;
time.tv_usec = (millis * 1000) % 1000000;
select_rv = select(sck + 1, &rfds, 0, 0, &time);
if (select_rv > 0)
{
return 1;
}
return 0;
}
/*****************************************************************************/
static int
send_init(struct wts_obj *wts)
{
char initmsg[64];
memset(initmsg, 0, 64);
/* insert channel name */
strncpy(initmsg, wts->name, 8);
/* insert open mode flags */
initmsg[16] = (wts->flags >> 0) & 0xff;
initmsg[17] = (wts->flags >> 8) & 0xff;
initmsg[18] = (wts->flags >> 16) & 0xff;
initmsg[19] = (wts->flags >> 24) & 0xff;
if (!can_send(wts->fd, 500))
{
LLOGLN(10, ("send_init: send() will block!"));
return 1;
}
if (send(wts->fd, initmsg, 64, 0) != 64)
{
LLOGLN(10, ("send_init: send() failed!"));
return 1;
}
LLOGLN(10, ("send_init: sent ok!"));
return 0;
}
/*****************************************************************************/
static int
get_display_num_from_display(char *display_text)
{
int index;
int mode;
int disp_index;
char disp[256];
index = 0;
disp_index = 0;
mode = 0;
while (display_text[index] != 0)
{
if (display_text[index] == ':')
{
mode = 1;
}
else if (display_text[index] == '.')
{
mode = 2;
}
else if (mode == 1)
{
disp[disp_index] = display_text[index];
disp_index++;
}
index++;
}
disp[disp_index] = 0;
return atoi(disp);
}
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