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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     pthread_cond_init(&xlib->cond, 0);
  66     return 1;
  67 }
  68
  69 static void _xcb_xlib_destroy(_xcb_xlib *xlib)
  70 {
  71     pthread_cond_destroy(&xlib->cond);
  72 }
  73
  74 static int write_setup(xcb_connection_t *c, xcb_auth_info_t *auth_info)
  75 {
  76     static const char pad[3];
  77     xcb_setup_request_t out;
  78     struct iovec parts[6];
  79     int count = 0;
  80     int endian = 0x01020304;
  81     int ret;
  82
  83     memset(&out, 0, sizeof(out));
  84
  85     /* B = 0x42 = MSB first, l = 0x6c = LSB first */
  86     if(htonl(endian) == endian)
  87         out.byte_order = 0x42;
  88     else
  89         out.byte_order = 0x6c;
  90     out.protocol_major_version = X_PROTOCOL;
  91     out.protocol_minor_version = X_PROTOCOL_REVISION;
  92     out.authorization_protocol_name_len = 0;
  93     out.authorization_protocol_data_len = 0;
  94     parts[count].iov_len = sizeof(xcb_setup_request_t);
  95     parts[count++].iov_base = &out;
  96     parts[count].iov_len = XCB_PAD(sizeof(xcb_setup_request_t));
  97     parts[count++].iov_base = (char *) pad;
  98
  99     if(auth_info)
 100     {
 101         parts[count].iov_len = out.authorization_protocol_name_len = auth_info->namelen;
 102         parts[count++].iov_base = auth_info->name;
 103         parts[count].iov_len = XCB_PAD(out.authorization_protocol_name_len);
 104         parts[count++].iov_base = (char *) pad;
 105         parts[count].iov_len = out.authorization_protocol_data_len = auth_info->datalen;
 106         parts[count++].iov_base = auth_info->data;
 107         parts[count].iov_len = XCB_PAD(out.authorization_protocol_data_len);
 108         parts[count++].iov_base = (char *) pad;
 109     }
 110     assert(count <= sizeof(parts) / sizeof(*parts));
 111
 112     _xcb_lock_io(c);
 113     {
 114         struct iovec *parts_ptr = parts;
 115         ret = _xcb_out_send(c, &parts_ptr, &count);
 116     }
 117     _xcb_unlock_io(c);
 118     return ret;
 119 }
 120
 121 static int read_setup(xcb_connection_t *c)
 122 {
 123     /* Read the server response */
 124     c->setup = malloc(sizeof(xcb_setup_generic_t));
 125     if(!c->setup)
 126         return 0;
 127
 128     if(_xcb_in_read_block(c, c->setup, sizeof(xcb_setup_generic_t)) != sizeof(xcb_setup_generic_t))
 129         return 0;
 130
 131     {
 132         void *tmp = realloc(c->setup, c->setup->length * 4 + sizeof(xcb_setup_generic_t));
 133         if(!tmp)
 134             return 0;
 135         c->setup = tmp;
 136     }
 137
 138     if(_xcb_in_read_block(c, (char *) c->setup + sizeof(xcb_setup_generic_t), c->setup->length * 4) <= 0)
 139         return 0;
 140
 141     /* 0 = failed, 2 = authenticate, 1 = success */
 142     switch(c->setup->status)
 143     {
 144     case 0: /* failed */
 145         {
 146             xcb_setup_failed_t *setup = (xcb_setup_failed_t *) c->setup;
 147             write(STDERR_FILENO, xcb_setup_failed_reason(setup), xcb_setup_failed_reason_length(setup));
 148             return 0;
 149         }
 150
 151     case 2: /* authenticate */
 152         {
 153             xcb_setup_authenticate_t *setup = (xcb_setup_authenticate_t *) c->setup;
 154             write(STDERR_FILENO, xcb_setup_authenticate_reason(setup), xcb_setup_authenticate_reason_length(setup));
 155             return 0;
 156         }
 157     }
 158
 159     return 1;
 160 }
 161
 162 /* precondition: there must be something for us to write. */
 163 static int write_vec(xcb_connection_t *c, struct iovec **vector, int *count)
 164 {
 165     int n;
 166     assert(!c->out.queue_len);
 167     n = writev(c->fd, *vector, *count);
 168     if(n < 0 && errno == EAGAIN)
 169         return 1;
 170     if(n <= 0)
 171     {
 172         _xcb_conn_shutdown(c);
 173         return 0;
 174     }
 175
 176     for(; *count; --*count, ++*vector)
 177     {
 178         int cur = (*vector)->iov_len;
 179         if(cur > n)
 180             cur = n;
 181         (*vector)->iov_len -= cur;
 182         (*vector)->iov_base = (char *) (*vector)->iov_base + cur;
 183         n -= cur;
 184         if((*vector)->iov_len)
 185             break;
 186     }
 187     if(!*count)
 188         *vector = 0;
 189     assert(n == 0);
 190     return 1;
 191 }
 192
 193 /* Public interface */
 194
 195 const xcb_setup_t *xcb_get_setup(xcb_connection_t *c)
 196 {
 197     if(c->has_error)
 198         return 0;
 199     /* doesn't need locking because it's never written to. */
 200     return c->setup;
 201 }
 202
 203 int xcb_get_file_descriptor(xcb_connection_t *c)
 204 {
 205     if(c->has_error)
 206         return -1;
 207     /* doesn't need locking because it's never written to. */
 208     return c->fd;
 209 }
 210
 211 int xcb_connection_has_error(xcb_connection_t *c)
 212 {
 213     /* doesn't need locking because it's read and written atomically. */
 214     return c->has_error;
 215 }
 216
 217 xcb_connection_t *xcb_connect_to_fd(int fd, xcb_auth_info_t *auth_info)
 218 {
 219     xcb_connection_t* c;
 220
 221     c = calloc(1, sizeof(xcb_connection_t));
 222     if(!c)
 223         return (xcb_connection_t *) &error_connection;
 224
 225     c->fd = fd;
 226
 227     if(!(
 228         set_fd_flags(fd) &&
 229         pthread_mutex_init(&c->iolock, 0) == 0 &&
 230         _xcb_xlib_init(&c->xlib) &&
 231         _xcb_in_init(&c->in) &&
 232         _xcb_out_init(&c->out) &&
 233         write_setup(c, auth_info) &&
 234         read_setup(c) &&
 235         _xcb_ext_init(c) &&
 236         _xcb_xid_init(c)
 237         ))
 238     {
 239         xcb_disconnect(c);
 240         return (xcb_connection_t *) &error_connection;
 241     }
 242
 243     return c;
 244 }
 245
 246 void xcb_disconnect(xcb_connection_t *c)
 247 {
 248     if(c->has_error)
 249         return;
 250
 251     free(c->setup);
 252     close(c->fd);
 253
 254     pthread_mutex_destroy(&c->iolock);
 255     _xcb_xlib_destroy(&c->xlib);
 256     _xcb_in_destroy(&c->in);
 257     _xcb_out_destroy(&c->out);
 258
 259     _xcb_ext_destroy(c);
 260     _xcb_xid_destroy(c);
 261
 262     free(c);
 263 }
 264
 265 /* Private interface */
 266
 267 void _xcb_conn_shutdown(xcb_connection_t *c)
 268 {
 269     c->has_error = 1;
 270 }
 271
 272 void _xcb_lock_io(xcb_connection_t *c)
 273 {
 274     pthread_mutex_lock(&c->iolock);
 275     while(c->xlib.lock)
 276     {
 277         if(pthread_equal(c->xlib.thread, pthread_self()))
 278             break;
 279         pthread_cond_wait(&c->xlib.cond, &c->iolock);
 280     }
 281 }
 282
 283 void _xcb_unlock_io(xcb_connection_t *c)
 284 {
 285     pthread_mutex_unlock(&c->iolock);
 286 }
 287
 288 int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)
 289 {
 290     int ret;
 291     fd_set rfds, wfds;
 292
 293     /* If the thing I should be doing is already being done, wait for it. */
 294     if(count ? c->out.writing : c->in.reading)
 295     {
 296         pthread_cond_wait(cond, &c->iolock);
 297         return 1;
 298     }
 299
 300     FD_ZERO(&rfds);
 301     FD_SET(c->fd, &rfds);
 302     ++c->in.reading;
 303
 304     FD_ZERO(&wfds);
 305     if(count)
 306     {
 307         FD_SET(c->fd, &wfds);
 308         ++c->out.writing;
 309     }
 310
 311     _xcb_unlock_io(c);
 312     do {
 313         ret = select(c->fd + 1, &rfds, &wfds, 0, 0);
 314     } while (ret == -1 && errno == EINTR);
 315     if (ret < 0)
 316     {
 317         _xcb_conn_shutdown(c);
 318         ret = 0;
 319     }
 320     _xcb_lock_io(c);
 321
 322     if(ret)
 323     {
 324         if(FD_ISSET(c->fd, &rfds))
 325             ret = ret && _xcb_in_read(c);
 326
 327         if(FD_ISSET(c->fd, &wfds))
 328             ret = ret && write_vec(c, vector, count);
 329     }
 330
 331     if(count)
 332         --c->out.writing;
 333     --c->in.reading;
 334
 335     return ret;
 336 }