aboutsummaryrefslogtreecommitdiff
path: root/libxcb/src/xcb_conn.c
blob: e1d2e762cf333c29b949380599d72a696aa7cd81 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 * Except as contained in this notice, the names of the authors or their
 * institutions shall not be used in advertising or otherwise to promote the
 * sale, use or other dealings in this Software without prior written
 * authorization from the authors.
 */

/* Connection management: the core of XCB. */

#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef _MSC_VER
#include <X11/Xwinsock.h>
#define STDERR_FILENO stderr
#else
#include <unistd.h>
#include <netinet/in.h>
#include <sys/select.h>
#endif
#include <fcntl.h>
#include <errno.h>

#include "xcb.h"
#include "xcbint.h"

#include <X11/Xtrans/Xtrans.h>

typedef struct {
    uint8_t  status;
    uint8_t  pad0[5];
    uint16_t length;
} xcb_setup_generic_t;

static const int error_connection = 1;

#ifdef _MSC_VER
size_t writev(int fildes, const struct iovec *iov, int iovcnt)
{
  int i, r;
  char *p;
  size_t l, sum;

  /* We should buffer */
  sum= 0;
  for (i= 0; i<iovcnt; i++)
  {
    p= iov[i].iov_base;
    l= iov[i].iov_len;
    while (l > 0)
    {
      r= send(fildes, p, l, 0);
      if (r <= 0)
      {
        errno =WSAGetLastError();
        if(errno == WSAEWOULDBLOCK)
          errno = EAGAIN;
        assert(sum == 0);
        return r;
      }
      p += r;
      l -= r;
      sum += r;
    }
  }
  return sum;
}
#endif

static int set_fd_flags(const int fd)
{
#ifdef _MSC_VER
    unsigned long arg = 1;
    int ret = ioctlsocket (fd, FIONBIO, &arg);
#else
    int flags = fcntl(fd, F_GETFL, 0);
    if(flags == -1)
        return 0;
    flags |= O_NONBLOCK;
    if(fcntl(fd, F_SETFL, flags) == -1)
        return 0;
    if(fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
        return 0;
#endif
    return 1;
}

static int _xcb_xlib_init(_xcb_xlib *xlib)
{
    xlib->lock = 0;
#ifndef NDEBUG
    xlib->sloppy_lock = (getenv("LIBXCB_ALLOW_SLOPPY_LOCK") != 0);
#endif
    pthread_cond_init(&xlib->cond, 0);
    return 1;
}

static void _xcb_xlib_destroy(_xcb_xlib *xlib)
{
    pthread_cond_destroy(&xlib->cond);
}

static int write_setup(xcb_connection_t *c, xcb_auth_info_t *auth_info)
{
    static const char pad[3];
    xcb_setup_request_t out;
    struct iovec parts[6];
    int count = 0;
    int endian = 0x01020304;
    int ret;

    memset(&out, 0, sizeof(out));

    /* B = 0x42 = MSB first, l = 0x6c = LSB first */
    if(htonl(endian) == endian)
        out.byte_order = 0x42;
    else
        out.byte_order = 0x6c;
    out.protocol_major_version = X_PROTOCOL;
    out.protocol_minor_version = X_PROTOCOL_REVISION;
    out.authorization_protocol_name_len = 0;
    out.authorization_protocol_data_len = 0;
    parts[count].iov_len = sizeof(xcb_setup_request_t);
    parts[count++].iov_base = &out;
    parts[count].iov_len = XCB_PAD(sizeof(xcb_setup_request_t));
    parts[count++].iov_base = (char *) pad;

    if(auth_info)
    {
        parts[count].iov_len = out.authorization_protocol_name_len = auth_info->namelen;
        parts[count++].iov_base = auth_info->name;
        parts[count].iov_len = XCB_PAD(out.authorization_protocol_name_len);
        parts[count++].iov_base = (char *) pad;
        parts[count].iov_len = out.authorization_protocol_data_len = auth_info->datalen;
        parts[count++].iov_base = auth_info->data;
        parts[count].iov_len = XCB_PAD(out.authorization_protocol_data_len);
        parts[count++].iov_base = (char *) pad;
    }
    assert(count <= sizeof(parts) / sizeof(*parts));

    _xcb_lock_io(c);
    {
        struct iovec *parts_ptr = parts;
        ret = _xcb_out_send(c, &parts_ptr, &count);
    }
    _xcb_unlock_io(c);
    return ret;
}

static int read_setup(xcb_connection_t *c)
{
    /* Read the server response */
    c->setup = malloc(sizeof(xcb_setup_generic_t));
    if(!c->setup)
        return 0;

    if(_xcb_in_read_block(c, c->setup, sizeof(xcb_setup_generic_t)) != sizeof(xcb_setup_generic_t))
        return 0;

    {
        void *tmp = realloc(c->setup, c->setup->length * 4 + sizeof(xcb_setup_generic_t));
        if(!tmp)
            return 0;
        c->setup = tmp;
    }

    if(_xcb_in_read_block(c, (char *) c->setup + sizeof(xcb_setup_generic_t), c->setup->length * 4) <= 0)
        return 0;

    /* 0 = failed, 2 = authenticate, 1 = success */
    switch(c->setup->status)
    {
    case 0: /* failed */
        {
            xcb_setup_failed_t *setup = (xcb_setup_failed_t *) c->setup;
            write(STDERR_FILENO, xcb_setup_failed_reason(setup), xcb_setup_failed_reason_length(setup));
            return 0;
        }

    case 2: /* authenticate */
        {
            xcb_setup_authenticate_t *setup = (xcb_setup_authenticate_t *) c->setup;
            write(STDERR_FILENO, xcb_setup_authenticate_reason(setup), xcb_setup_authenticate_reason_length(setup));
            return 0;
        }
    }

    return 1;
}

/* precondition: there must be something for us to write. */
static int write_vec(xcb_connection_t *c, struct iovec **vector, int *count)
{
    int n;
    assert(!c->out.queue_len);
    n = writev(c->fd, *vector, *count);
    if(n < 0 && errno == EAGAIN)
        return 1;
    if(n <= 0)
    {
        _xcb_conn_shutdown(c);
        return 0;
    }

    for(; *count; --*count, ++*vector)
    {
        int cur = (*vector)->iov_len;
        if(cur > n)
            cur = n;
        (*vector)->iov_len -= cur;
        (*vector)->iov_base = (char *) (*vector)->iov_base + cur;
        n -= cur;
        if((*vector)->iov_len)
            break;
    }
    if(!*count)
        *vector = 0;
    assert(n == 0);
    return 1;
}

/* Public interface */

const xcb_setup_t *xcb_get_setup(xcb_connection_t *c)
{
    if(c->has_error)
        return 0;
    /* doesn't need locking because it's never written to. */
    return c->setup;
}

int xcb_get_file_descriptor(xcb_connection_t *c)
{
    if(c->has_error)
        return -1;
    /* doesn't need locking because it's never written to. */
    return c->fd;
}

int xcb_connection_has_error(xcb_connection_t *c)
{
    /* doesn't need locking because it's read and written atomically. */
    return c->has_error;
}

xcb_connection_t *xcb_connect_to_fd(int fd, xcb_auth_info_t *auth_info)
{
    xcb_connection_t* c;

    c = calloc(1, sizeof(xcb_connection_t));
    if(!c)
        return (xcb_connection_t *) &error_connection;

    c->fd = fd;

    if(!(
        set_fd_flags(fd) &&
        pthread_mutex_init(&c->iolock, 0) == 0 &&
        _xcb_xlib_init(&c->xlib) &&
        _xcb_in_init(&c->in) &&
        _xcb_out_init(&c->out) &&
        write_setup(c, auth_info) &&
        read_setup(c) &&
        _xcb_ext_init(c) &&
        _xcb_xid_init(c)
        ))
    {
        xcb_disconnect(c);
        return (xcb_connection_t *) &error_connection;
    }

    return c;
}

void xcb_disconnect(xcb_connection_t *c)
{
    if(c->has_error)
        return;

    free(c->setup);
    close(c->fd);

    pthread_mutex_destroy(&c->iolock);
    _xcb_xlib_destroy(&c->xlib);
    _xcb_in_destroy(&c->in);
    _xcb_out_destroy(&c->out);

    _xcb_ext_destroy(c);
    _xcb_xid_destroy(c);

    free(c);
}

/* Private interface */

void _xcb_conn_shutdown(xcb_connection_t *c)
{
    c->has_error = 1;
}

void _xcb_lock_io(xcb_connection_t *c)
{
    pthread_mutex_lock(&c->iolock);
    while(c->xlib.lock)
    {
        if(pthread_equal(c->xlib.thread, pthread_self()))
            break;
        pthread_cond_wait(&c->xlib.cond, &c->iolock);
    }
}

void _xcb_unlock_io(xcb_connection_t *c)
{
    pthread_mutex_unlock(&c->iolock);
}

void _xcb_wait_io(xcb_connection_t *c, pthread_cond_t *cond)
{
    int xlib_locked = c->xlib.lock;
    if(xlib_locked)
    {
        c->xlib.lock = 0;
        pthread_cond_broadcast(&c->xlib.cond);
    }
    pthread_cond_wait(cond, &c->iolock);
    if(xlib_locked)
    {
        while(c->xlib.lock)
            pthread_cond_wait(&c->xlib.cond, &c->iolock);
        c->xlib.lock = 1;
        c->xlib.thread = pthread_self();
    }
}

int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)
{
    int ret, xlib_locked;
    fd_set rfds, wfds;

    /* If the thing I should be doing is already being done, wait for it. */
    if(count ? c->out.writing : c->in.reading)
    {
        _xcb_wait_io(c, cond);
        return 1;
    }

    FD_ZERO(&rfds);
    FD_SET(c->fd, &rfds);
    ++c->in.reading;

    FD_ZERO(&wfds);
    if(count)
    {
        FD_SET(c->fd, &wfds);
        ++c->out.writing;
    }

    xlib_locked = c->xlib.lock;
    if(xlib_locked)
    {
        c->xlib.lock = 0;
        pthread_cond_broadcast(&c->xlib.cond);
    }
    _xcb_unlock_io(c);
    do {
	ret = select(c->fd + 1, &rfds, &wfds, 0, 0);
	if (ret==SOCKET_ERROR)
	{
	   ret=-1;
           errno = WSAGetLastError();
	   if (errno == WSAEINTR)
		   errno=EINTR;
	}
    } while (ret == -1 && errno == EINTR);
    if (ret < 0)
    {
        _xcb_conn_shutdown(c);
	ret = 0;
    }
    _xcb_lock_io(c);
    if(xlib_locked)
    {
        c->xlib.lock = 1;
        c->xlib.thread = pthread_self();
    }

    if(ret)
    {
        if(FD_ISSET(c->fd, &rfds))
            ret = ret && _xcb_in_read(c);

        if(FD_ISSET(c->fd, &wfds))
            ret = ret && write_vec(c, vector, count);
    }

    if(count)
        --c->out.writing;
    --c->in.reading;

    return ret;
}