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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     long 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 write_setup(xcb_connection_t *c, xcb_auth_info_t *auth_info)
  63 {
  64     static const char pad[3];
  65     xcb_setup_request_t out;
  66     struct iovec parts[6];
  67     int count = 0;
  68     int endian = 0x01020304;
  69     int ret;
  70
  71     memset(&out, 0, sizeof(out));
  72
  73     /* B = 0x42 = MSB first, l = 0x6c = LSB first */
  74     if(htonl(endian) == endian)
  75         out.byte_order = 0x42;
  76     else
  77         out.byte_order = 0x6c;
  78     out.protocol_major_version = X_PROTOCOL;
  79     out.protocol_minor_version = X_PROTOCOL_REVISION;
  80     out.authorization_protocol_name_len = 0;
  81     out.authorization_protocol_data_len = 0;
  82     parts[count].iov_len = sizeof(xcb_setup_request_t);
  83     parts[count++].iov_base = &out;
  84     parts[count].iov_len = XCB_PAD(sizeof(xcb_setup_request_t));
  85     parts[count++].iov_base = (char *) pad;
  86
  87     if(auth_info)
  88     {
  89         parts[count].iov_len = out.authorization_protocol_name_len = auth_info->namelen;
  90         parts[count++].iov_base = auth_info->name;
  91         parts[count].iov_len = XCB_PAD(out.authorization_protocol_name_len);
  92         parts[count++].iov_base = (char *) pad;
  93         parts[count].iov_len = out.authorization_protocol_data_len = auth_info->datalen;
  94         parts[count++].iov_base = auth_info->data;
  95         parts[count].iov_len = XCB_PAD(out.authorization_protocol_data_len);
  96         parts[count++].iov_base = (char *) pad;
  97     }
  98     assert(count <= sizeof(parts) / sizeof(*parts));
  99
 100     _xcb_lock_io(c);
 101     {
 102         struct iovec *parts_ptr = parts;
 103         ret = _xcb_out_send(c, &parts_ptr, &count);
 104     }
 105     _xcb_unlock_io(c);
 106     return ret;
 107 }
 108
 109 static int read_setup(xcb_connection_t *c)
 110 {
 111     /* Read the server response */
 112     c->setup = malloc(sizeof(xcb_setup_generic_t));
 113     if(!c->setup)
 114         return 0;
 115
 116     if(_xcb_in_read_block(c, c->setup, sizeof(xcb_setup_generic_t)) != sizeof(xcb_setup_generic_t))
 117         return 0;
 118
 119     {
 120         void *tmp = realloc(c->setup, c->setup->length * 4 + sizeof(xcb_setup_generic_t));
 121         if(!tmp)
 122             return 0;
 123         c->setup = tmp;
 124     }
 125
 126     if(_xcb_in_read_block(c, (char *) c->setup + sizeof(xcb_setup_generic_t), c->setup->length * 4) <= 0)
 127         return 0;
 128
 129     /* 0 = failed, 2 = authenticate, 1 = success */
 130     switch(c->setup->status)
 131     {
 132     case 0: /* failed */
 133         {
 134             xcb_setup_failed_t *setup = (xcb_setup_failed_t *) c->setup;
 135             write(STDERR_FILENO, xcb_setup_failed_reason(setup), xcb_setup_failed_reason_length(setup));
 136             return 0;
 137         }
 138
 139     case 2: /* authenticate */
 140         {
 141             xcb_setup_authenticate_t *setup = (xcb_setup_authenticate_t *) c->setup;
 142             write(STDERR_FILENO, xcb_setup_authenticate_reason(setup), xcb_setup_authenticate_reason_length(setup));
 143             return 0;
 144         }
 145     }
 146
 147     return 1;
 148 }
 149
 150 /* precondition: there must be something for us to write. */
 151 static int write_vec(xcb_connection_t *c, struct iovec **vector, int *count)
 152 {
 153     int n;
 154     assert(!c->out.queue_len);
 155     n = writev(c->fd, *vector, *count);
 156     if(n < 0 && errno == EAGAIN)
 157         return 1;
 158     if(n <= 0)
 159     {
 160         _xcb_conn_shutdown(c);
 161         return 0;
 162     }
 163
 164     for(; *count; --*count, ++*vector)
 165     {
 166         int cur = (*vector)->iov_len;
 167         if(cur > n)
 168             cur = n;
 169         (*vector)->iov_len -= cur;
 170         (*vector)->iov_base = (char *) (*vector)->iov_base + cur;
 171         n -= cur;
 172         if((*vector)->iov_len)
 173             break;
 174     }
 175     if(!*count)
 176         *vector = 0;
 177     assert(n == 0);
 178     return 1;
 179 }
 180
 181 /* Public interface */
 182
 183 const xcb_setup_t *xcb_get_setup(xcb_connection_t *c)
 184 {
 185     if(c->has_error)
 186         return 0;
 187     /* doesn't need locking because it's never written to. */
 188     return c->setup;
 189 }
 190
 191 int xcb_get_file_descriptor(xcb_connection_t *c)
 192 {
 193     if(c->has_error)
 194         return -1;
 195     /* doesn't need locking because it's never written to. */
 196     return c->fd;
 197 }
 198
 199 int xcb_connection_has_error(xcb_connection_t *c)
 200 {
 201     /* doesn't need locking because it's read and written atomically. */
 202     return c->has_error;
 203 }
 204
 205 xcb_connection_t *xcb_connect_to_fd(int fd, xcb_auth_info_t *auth_info)
 206 {
 207     xcb_connection_t* c;
 208
 209     c = calloc(1, sizeof(xcb_connection_t));
 210     if(!c)
 211         return (xcb_connection_t *) &error_connection;
 212
 213     c->fd = fd;
 214
 215     if(!(
 216         set_fd_flags(fd) &&
 217         pthread_mutex_init(&c->iolock, 0) == 0 &&
 218         _xcb_in_init(&c->in) &&
 219         _xcb_out_init(&c->out) &&
 220         write_setup(c, auth_info) &&
 221         read_setup(c) &&
 222         _xcb_ext_init(c) &&
 223         _xcb_xid_init(c)
 224         ))
 225     {
 226         xcb_disconnect(c);
 227         return (xcb_connection_t *) &error_connection;
 228     }
 229
 230     return c;
 231 }
 232
 233 void xcb_disconnect(xcb_connection_t *c)
 234 {
 235     if(c->has_error)
 236         return;
 237
 238     free(c->setup);
 239     close(c->fd);
 240
 241     pthread_mutex_destroy(&c->iolock);
 242     _xcb_in_destroy(&c->in);
 243     _xcb_out_destroy(&c->out);
 244
 245     _xcb_ext_destroy(c);
 246     _xcb_xid_destroy(c);
 247
 248     free(c);
 249 }
 250
 251 /* Private interface */
 252
 253 void _xcb_conn_shutdown(xcb_connection_t *c)
 254 {
 255     c->has_error = 1;
 256 }
 257
 258 void _xcb_lock_io(xcb_connection_t *c)
 259 {
 260     pthread_mutex_lock(&c->iolock);
 261 }
 262
 263 void _xcb_unlock_io(xcb_connection_t *c)
 264 {
 265     pthread_mutex_unlock(&c->iolock);
 266 }
 267
 268 int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)
 269 {
 270     int ret;
 271     fd_set rfds, wfds;
 272
 273     /* If the thing I should be doing is already being done, wait for it. */
 274     if(count ? c->out.writing : c->in.reading)
 275     {
 276         pthread_cond_wait(cond, &c->iolock);
 277         return 1;
 278     }
 279
 280     FD_ZERO(&rfds);
 281     FD_SET(c->fd, &rfds);
 282     ++c->in.reading;
 283
 284     FD_ZERO(&wfds);
 285     if(count)
 286     {
 287         FD_SET(c->fd, &wfds);
 288         ++c->out.writing;
 289     }
 290
 291     _xcb_unlock_io(c);
 292     do {
 293         ret = select(c->fd + 1, &rfds, &wfds, 0, 0);
 294     } while (ret == -1 && errno == EINTR);
 295     if (ret < 0)
 296     {
 297         _xcb_conn_shutdown(c);
 298         ret = 0;
 299     }
 300     _xcb_lock_io(c);
 301
 302     if(ret)
 303     {
 304         if(FD_ISSET(c->fd, &rfds))
 305             ret = ret && _xcb_in_read(c);
 306
 307         if(FD_ISSET(c->fd, &wfds))
 308             ret = ret && write_vec(c, vector, count);
 309     }
 310
 311     if(count)
 312         --c->out.writing;
 313     --c->in.reading;
 314
 315     return ret;
 316 }