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   1 /* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.
   2  *
   3  * Permission is hereby granted, free of charge, to any person obtaining a
   4  * copy of this software and associated documentation files (the "Software"),
   5  * to deal in the Software without restriction, including without limitation
   6  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   7  * and/or sell copies of the Software, and to permit persons to whom the
   8  * Software is furnished to do so, subject to the following conditions:
   9  *
  10  * The above copyright notice and this permission notice shall be included in
  11  * all copies or substantial portions of the Software.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  16  * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  17  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  18  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19  *
  20  * Except as contained in this notice, the names of the authors or their
  21  * institutions shall not be used in advertising or otherwise to promote the
  22  * sale, use or other dealings in this Software without prior written
  23  * authorization from the authors.
  24  */
  25
  26 /* Connection management: the core of XCB. */
  27
  28 #include <assert.h>
  29 #include <string.h>
  30 #include <stdio.h>
  31 #include <unistd.h>
  32 #include <stdlib.h>
  33 #include <netinet/in.h>
  34 #include <sys/select.h>
  35 #include <fcntl.h>
  36 #include <errno.h>
  37
  38 #include "xcb.h"
  39 #include "xcbint.h"
  40
  41 typedef struct {
  42     uint8_t  status;
  43     uint8_t  pad0[5];
  44     uint16_t length;
  45 } xcb_setup_generic_t;
  46
  47 static const int error_connection = 1;
  48
  49 static int set_fd_flags(const int fd)
  50 {
  51     int flags = fcntl(fd, F_GETFL, 0);
  52     if(flags == -1)
  53         return 0;
  54     flags |= O_NONBLOCK;
  55     if(fcntl(fd, F_SETFL, flags) == -1)
  56         return 0;
  57     if(fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
  58         return 0;
  59     return 1;
  60 }
  61
  62 static int _xcb_xlib_init(_xcb_xlib *xlib)
  63 {
  64     xlib->lock = 0;
  65 #ifndef NDEBUG
  66     xlib->sloppy_lock = (getenv("LIBXCB_ALLOW_SLOPPY_LOCK") != 0);
  67 #endif
  68     pthread_cond_init(&xlib->cond, 0);
  69     return 1;
  70 }
  71
  72 static void _xcb_xlib_destroy(_xcb_xlib *xlib)
  73 {
  74     pthread_cond_destroy(&xlib->cond);
  75 }
  76
  77 static int write_setup(xcb_connection_t *c, xcb_auth_info_t *auth_info)
  78 {
  79     static const char pad[3];
  80     xcb_setup_request_t out;
  81     struct iovec parts[6];
  82     int count = 0;
  83     int endian = 0x01020304;
  84     int ret;
  85
  86     memset(&out, 0, sizeof(out));
  87
  88     /* B = 0x42 = MSB first, l = 0x6c = LSB first */
  89     if(htonl(endian) == endian)
  90         out.byte_order = 0x42;
  91     else
  92         out.byte_order = 0x6c;
  93     out.protocol_major_version = X_PROTOCOL;
  94     out.protocol_minor_version = X_PROTOCOL_REVISION;
  95     out.authorization_protocol_name_len = 0;
  96     out.authorization_protocol_data_len = 0;
  97     parts[count].iov_len = sizeof(xcb_setup_request_t);
  98     parts[count++].iov_base = &out;
  99     parts[count].iov_len = XCB_PAD(sizeof(xcb_setup_request_t));
 100     parts[count++].iov_base = (char *) pad;
 101
 102     if(auth_info)
 103     {
 104         parts[count].iov_len = out.authorization_protocol_name_len = auth_info->namelen;
 105         parts[count++].iov_base = auth_info->name;
 106         parts[count].iov_len = XCB_PAD(out.authorization_protocol_name_len);
 107         parts[count++].iov_base = (char *) pad;
 108         parts[count].iov_len = out.authorization_protocol_data_len = auth_info->datalen;
 109         parts[count++].iov_base = auth_info->data;
 110         parts[count].iov_len = XCB_PAD(out.authorization_protocol_data_len);
 111         parts[count++].iov_base = (char *) pad;
 112     }
 113     assert(count <= sizeof(parts) / sizeof(*parts));
 114
 115     _xcb_lock_io(c);
 116     {
 117         struct iovec *parts_ptr = parts;
 118         ret = _xcb_out_send(c, &parts_ptr, &count);
 119     }
 120     _xcb_unlock_io(c);
 121     return ret;
 122 }
 123
 124 static int read_setup(xcb_connection_t *c)
 125 {
 126     /* Read the server response */
 127     c->setup = malloc(sizeof(xcb_setup_generic_t));
 128     if(!c->setup)
 129         return 0;
 130
 131     if(_xcb_in_read_block(c, c->setup, sizeof(xcb_setup_generic_t)) != sizeof(xcb_setup_generic_t))
 132         return 0;
 133
 134     {
 135         void *tmp = realloc(c->setup, c->setup->length * 4 + sizeof(xcb_setup_generic_t));
 136         if(!tmp)
 137             return 0;
 138         c->setup = tmp;
 139     }
 140
 141     if(_xcb_in_read_block(c, (char *) c->setup + sizeof(xcb_setup_generic_t), c->setup->length * 4) <= 0)
 142         return 0;
 143
 144     /* 0 = failed, 2 = authenticate, 1 = success */
 145     switch(c->setup->status)
 146     {
 147     case 0: /* failed */
 148         {
 149             xcb_setup_failed_t *setup = (xcb_setup_failed_t *) c->setup;
 150             write(STDERR_FILENO, xcb_setup_failed_reason(setup), xcb_setup_failed_reason_length(setup));
 151             return 0;
 152         }
 153
 154     case 2: /* authenticate */
 155         {
 156             xcb_setup_authenticate_t *setup = (xcb_setup_authenticate_t *) c->setup;
 157             write(STDERR_FILENO, xcb_setup_authenticate_reason(setup), xcb_setup_authenticate_reason_length(setup));
 158             return 0;
 159         }
 160     }
 161
 162     return 1;
 163 }
 164
 165 /* precondition: there must be something for us to write. */
 166 static int write_vec(xcb_connection_t *c, struct iovec **vector, int *count)
 167 {
 168     int n;
 169     assert(!c->out.queue_len);
 170     n = writev(c->fd, *vector, *count);
 171     if(n < 0 && errno == EAGAIN)
 172         return 1;
 173     if(n <= 0)
 174     {
 175         _xcb_conn_shutdown(c);
 176         return 0;
 177     }
 178
 179     for(; *count; --*count, ++*vector)
 180     {
 181         int cur = (*vector)->iov_len;
 182         if(cur > n)
 183             cur = n;
 184         (*vector)->iov_len -= cur;
 185         (*vector)->iov_base = (char *) (*vector)->iov_base + cur;
 186         n -= cur;
 187         if((*vector)->iov_len)
 188             break;
 189     }
 190     if(!*count)
 191         *vector = 0;
 192     assert(n == 0);
 193     return 1;
 194 }
 195
 196 /* Public interface */
 197
 198 const xcb_setup_t *xcb_get_setup(xcb_connection_t *c)
 199 {
 200     if(c->has_error)
 201         return 0;
 202     /* doesn't need locking because it's never written to. */
 203     return c->setup;
 204 }
 205
 206 int xcb_get_file_descriptor(xcb_connection_t *c)
 207 {
 208     if(c->has_error)
 209         return -1;
 210     /* doesn't need locking because it's never written to. */
 211     return c->fd;
 212 }
 213
 214 int xcb_connection_has_error(xcb_connection_t *c)
 215 {
 216     /* doesn't need locking because it's read and written atomically. */
 217     return c->has_error;
 218 }
 219
 220 xcb_connection_t *xcb_connect_to_fd(int fd, xcb_auth_info_t *auth_info)
 221 {
 222     xcb_connection_t* c;
 223
 224     c = calloc(1, sizeof(xcb_connection_t));
 225     if(!c)
 226         return (xcb_connection_t *) &error_connection;
 227
 228     c->fd = fd;
 229
 230     if(!(
 231         set_fd_flags(fd) &&
 232         pthread_mutex_init(&c->iolock, 0) == 0 &&
 233         _xcb_xlib_init(&c->xlib) &&
 234         _xcb_in_init(&c->in) &&
 235         _xcb_out_init(&c->out) &&
 236         write_setup(c, auth_info) &&
 237         read_setup(c) &&
 238         _xcb_ext_init(c) &&
 239         _xcb_xid_init(c)
 240         ))
 241     {
 242         xcb_disconnect(c);
 243         return (xcb_connection_t *) &error_connection;
 244     }
 245
 246     return c;
 247 }
 248
 249 void xcb_disconnect(xcb_connection_t *c)
 250 {
 251     if(c->has_error)
 252         return;
 253
 254     free(c->setup);
 255     close(c->fd);
 256
 257     pthread_mutex_destroy(&c->iolock);
 258     _xcb_xlib_destroy(&c->xlib);
 259     _xcb_in_destroy(&c->in);
 260     _xcb_out_destroy(&c->out);
 261
 262     _xcb_ext_destroy(c);
 263     _xcb_xid_destroy(c);
 264
 265     free(c);
 266 }
 267
 268 /* Private interface */
 269
 270 void _xcb_conn_shutdown(xcb_connection_t *c)
 271 {
 272     c->has_error = 1;
 273 }
 274
 275 void _xcb_lock_io(xcb_connection_t *c)
 276 {
 277     pthread_mutex_lock(&c->iolock);
 278     while(c->xlib.lock)
 279     {
 280         if(pthread_equal(c->xlib.thread, pthread_self()))
 281             break;
 282         pthread_cond_wait(&c->xlib.cond, &c->iolock);
 283     }
 284 }
 285
 286 void _xcb_unlock_io(xcb_connection_t *c)
 287 {
 288     pthread_mutex_unlock(&c->iolock);
 289 }
 290
 291 int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)
 292 {
 293     int ret;
 294     fd_set rfds, wfds;
 295
 296     /* If the thing I should be doing is already being done, wait for it. */
 297     if(count ? c->out.writing : c->in.reading)
 298     {
 299         pthread_cond_wait(cond, &c->iolock);
 300         return 1;
 301     }
 302
 303     FD_ZERO(&rfds);
 304     FD_SET(c->fd, &rfds);
 305     ++c->in.reading;
 306
 307     FD_ZERO(&wfds);
 308     if(count)
 309     {
 310         FD_SET(c->fd, &wfds);
 311         ++c->out.writing;
 312     }
 313
 314     _xcb_unlock_io(c);
 315     do {
 316         ret = select(c->fd + 1, &rfds, &wfds, 0, 0);
 317     } while (ret == -1 && errno == EINTR);
 318     if (ret < 0)
 319     {
 320         _xcb_conn_shutdown(c);
 321         ret = 0;
 322     }
 323     _xcb_lock_io(c);
 324
 325     if(ret)
 326     {
 327         if(FD_ISSET(c->fd, &rfds))
 328             ret = ret && _xcb_in_read(c);
 329
 330         if(FD_ISSET(c->fd, &wfds))
 331             ret = ret && write_vec(c, vector, count);
 332     }
 333
 334     if(count)
 335         --c->out.writing;
 336     --c->in.reading;
 337
 338     return ret;
 339 }