backend/runloop.c

   1 /*
   2  * "$Id: runloop.c 7895 2008-09-02 19:19:43Z mike $"
   3  *
   4  *   Common run loop APIs for the Common UNIX Printing System (CUPS).
   5  *
   6  *   Copyright 2007-2008 by Apple Inc.
   7  *   Copyright 2006-2007 by Easy Software Products, all rights reserved.
   8  *
   9  *   These coded instructions, statements, and computer programs are the
  10  *   property of Apple Inc. and are protected by Federal copyright
  11  *   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
  12  *   "LICENSE" which should have been included with this file.  If this
  13  *   file is missing or damaged, see the license at "http://www.cups.org/".
  14  *
  15  *   This file is subject to the Apple OS-Developed Software exception.
  16  *
  17  * Contents:
  18  *
  19  *   backendDrainOutput() - Drain pending print data to the device.
  20  *   backendRunLoop()     - Read and write print and back-channel data.
  21  */
  22
  23 /*
  24  * Include necessary headers.
  25  */
  26
  27 #include "backend-private.h"
  28 #include <limits.h>
  29 #ifdef __hpux
  30 #  include <sys/time.h>
  31 #else
  32 #  include <sys/select.h>
  33 #endif /* __hpux */
  34
  35
  36 /*
  37  * 'backendDrainOutput()' - Drain pending print data to the device.
  38  */
  39
  40 int                                     /* O - 0 on success, -1 on error */
  41 backendDrainOutput(int print_fd,        /* I - Print file descriptor */
  42                    int device_fd)       /* I - Device file descriptor */
  43 {
  44   int           nfds;                   /* Maximum file descriptor value + 1 */
  45   fd_set        input;                  /* Input set for reading */
  46   ssize_t       print_bytes,            /* Print bytes read */
  47                 bytes;                  /* Bytes written */
  48   char          print_buffer[8192],     /* Print data buffer */
  49                 *print_ptr;             /* Pointer into print data buffer */
  50   struct timeval timeout;               /* Timeout for read... */
  51
  52
  53   fprintf(stderr, "DEBUG: backendDrainOutput(print_fd=%d, device_fd=%d)\n",
  54           print_fd, device_fd);
  55
  56  /*
  57   * Figure out the maximum file descriptor value to use with select()...
  58   */
  59
  60   nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
  61
  62  /*
  63   * Now loop until we are out of data from print_fd...
  64   */
  65
  66   for (;;)
  67   {
  68    /*
  69     * Use select() to determine whether we have data to copy around...
  70     */
  71
  72     FD_ZERO(&input);
  73     FD_SET(print_fd, &input);
  74
  75     timeout.tv_sec  = 0;
  76     timeout.tv_usec = 0;
  77
  78     if (select(nfds, &input, NULL, NULL, &timeout) < 0)
  79       return (-1);
  80
  81     if (!FD_ISSET(print_fd, &input))
  82       return (0);
  83
  84     if ((print_bytes = read(print_fd, print_buffer,
  85                             sizeof(print_buffer))) < 0)
  86     {
  87      /*
  88       * Read error - bail if we don't see EAGAIN or EINTR...
  89       */
  90
  91       if (errno != EAGAIN || errno != EINTR)
  92       {
  93         perror("ERROR: Unable to read print data");
  94         return (-1);
  95       }
  96
  97       print_bytes = 0;
  98     }
  99     else if (print_bytes == 0)
 100     {
 101      /*
 102       * End of file, return...
 103       */
 104
 105       return (0);
 106     }
 107
 108     fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
 109             (int)print_bytes);
 110
 111     for (print_ptr = print_buffer; print_bytes > 0;)
 112     {
 113       if ((bytes = write(device_fd, print_ptr, print_bytes)) < 0)
 114       {
 115        /*
 116         * Write error - bail if we don't see an error we can retry...
 117         */
 118
 119         if (errno != ENOSPC && errno != ENXIO && errno != EAGAIN &&
 120             errno != EINTR && errno != ENOTTY)
 121         {
 122           _cupsLangPrintf(stderr, _("ERROR: Unable to write print data: %s\n"),
 123                           strerror(errno));
 124           return (-1);
 125         }
 126       }
 127       else
 128       {
 129         fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
 130
 131         print_bytes -= bytes;
 132         print_ptr   += bytes;
 133       }
 134     }
 135   }
 136 }
 137
 138
 139 /*
 140  * 'backendRunLoop()' - Read and write print and back-channel data.
 141  */
 142
 143 ssize_t                                 /* O - Total bytes on success, -1 on error */
 144 backendRunLoop(
 145     int         print_fd,               /* I - Print file descriptor */
 146     int         device_fd,              /* I - Device file descriptor */
 147     int         snmp_fd,                /* I - SNMP socket or -1 if none */
 148     http_addr_t *addr,                  /* I - Address of device */
 149     int         use_bc,                 /* I - Use back-channel? */
 150     void        (*side_cb)(int, int, int, http_addr_t *, int))
 151                                         /* I - Side-channel callback */
 152 {
 153   int           nfds;                   /* Maximum file descriptor value + 1 */
 154   fd_set        input,                  /* Input set for reading */
 155                 output;                 /* Output set for writing */
 156   ssize_t       print_bytes,            /* Print bytes read */
 157                 bc_bytes,               /* Backchannel bytes read */
 158                 total_bytes,            /* Total bytes written */
 159                 bytes;                  /* Bytes written */
 160   int           paperout;               /* "Paper out" status */
 161   int           offline;                /* "Off-line" status */
 162   char          print_buffer[8192],     /* Print data buffer */
 163                 *print_ptr,             /* Pointer into print data buffer */
 164                 bc_buffer[1024];        /* Back-channel data buffer */
 165   struct timeval timeout;               /* Timeout for select() */
 166   time_t        curtime,                /* Current time */
 167                 snmp_update = 0;
 168 #if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
 169   struct sigaction action;              /* Actions for POSIX signals */
 170 #endif /* HAVE_SIGACTION && !HAVE_SIGSET */
 171
 172
 173   fprintf(stderr,
 174           "DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, snmp_fd=%d, "
 175           "addr=%p, use_bc=%d, side_cb=%p)\n",
 176           print_fd, device_fd, snmp_fd, addr, use_bc, side_cb);
 177
 178  /*
 179   * If we are printing data from a print driver on stdin, ignore SIGTERM
 180   * so that the driver can finish out any page data, e.g. to eject the
 181   * current page.  We only do this for stdin printing as otherwise there
 182   * is no way to cancel a raw print job...
 183   */
 184
 185   if (!print_fd)
 186   {
 187 #ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */
 188     sigset(SIGTERM, SIG_IGN);
 189 #elif defined(HAVE_SIGACTION)
 190     memset(&action, 0, sizeof(action));
 191
 192     sigemptyset(&action.sa_mask);
 193     action.sa_handler = SIG_IGN;
 194     sigaction(SIGTERM, &action, NULL);
 195 #else
 196     signal(SIGTERM, SIG_IGN);
 197 #endif /* HAVE_SIGSET */
 198   }
 199
 200  /*
 201   * Figure out the maximum file descriptor value to use with select()...
 202   */
 203
 204   nfds = (print_fd > device_fd ? print_fd : device_fd) + 1;
 205
 206  /*
 207   * Now loop until we are out of data from print_fd...
 208   */
 209
 210   for (print_bytes = 0, print_ptr = print_buffer, offline = -1,
 211            paperout = -1, total_bytes = 0;;)
 212   {
 213    /*
 214     * Use select() to determine whether we have data to copy around...
 215     */
 216
 217     FD_ZERO(&input);
 218     if (!print_bytes)
 219       FD_SET(print_fd, &input);
 220     if (use_bc)
 221       FD_SET(device_fd, &input);
 222     if (!print_bytes && side_cb)
 223       FD_SET(CUPS_SC_FD, &input);
 224
 225     FD_ZERO(&output);
 226     if (print_bytes || (!use_bc && !side_cb))
 227       FD_SET(device_fd, &output);
 228
 229     if (use_bc || side_cb)
 230     {
 231       timeout.tv_sec  = 5;
 232       timeout.tv_usec = 0;
 233
 234       if (select(nfds, &input, &output, NULL, &timeout) < 0)
 235       {
 236        /*
 237         * Pause printing to clear any pending errors...
 238         */
 239
 240         if (errno == ENXIO && offline != 1)
 241         {
 242           fputs("STATE: +offline-report\n", stderr);
 243           _cupsLangPuts(stderr, _("INFO: Printer is currently offline.\n"));
 244           offline = 1;
 245         }
 246         else if (errno == EINTR && total_bytes == 0)
 247         {
 248           fputs("DEBUG: Received an interrupt before any bytes were "
 249                 "written, aborting!\n", stderr);
 250           return (0);
 251         }
 252
 253         sleep(1);
 254         continue;
 255       }
 256     }
 257
 258    /*
 259     * Check if we have a side-channel request ready...
 260     */
 261
 262     if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
 263     {
 264      /*
 265       * Do the side-channel request, then start back over in the select
 266       * loop since it may have read from print_fd...
 267       */
 268
 269       (*side_cb)(print_fd, device_fd, snmp_fd, addr, use_bc);
 270       continue;
 271     }
 272
 273    /*
 274     * Check if we have back-channel data ready...
 275     */
 276
 277     if (FD_ISSET(device_fd, &input))
 278     {
 279       if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0)
 280       {
 281         fprintf(stderr,
 282                 "DEBUG: Received " CUPS_LLFMT " bytes of back-channel data!\n",
 283                 CUPS_LLCAST bc_bytes);
 284         cupsBackChannelWrite(bc_buffer, bc_bytes, 1.0);
 285       }
 286     }
 287
 288    /*
 289     * Check if we have print data ready...
 290     */
 291
 292     if (FD_ISSET(print_fd, &input))
 293     {
 294       if ((print_bytes = read(print_fd, print_buffer,
 295                               sizeof(print_buffer))) < 0)
 296       {
 297        /*
 298         * Read error - bail if we don't see EAGAIN or EINTR...
 299         */
 300
 301         if (errno != EAGAIN || errno != EINTR)
 302         {
 303           perror("ERROR: Unable to read print data");
 304           return (-1);
 305         }
 306
 307         print_bytes = 0;
 308       }
 309       else if (print_bytes == 0)
 310       {
 311        /*
 312         * End of file, break out of the loop...
 313         */
 314
 315         break;
 316       }
 317
 318       print_ptr = print_buffer;
 319
 320       fprintf(stderr, "DEBUG: Read %d bytes of print data...\n",
 321               (int)print_bytes);
 322     }
 323
 324    /*
 325     * Check if the device is ready to receive data and we have data to
 326     * send...
 327     */
 328
 329     if (print_bytes && FD_ISSET(device_fd, &output))
 330     {
 331       if ((bytes = write(device_fd, print_ptr, print_bytes)) < 0)
 332       {
 333        /*
 334         * Write error - bail if we don't see an error we can retry...
 335         */
 336
 337         if (errno == ENOSPC)
 338         {
 339           if (paperout != 1)
 340           {
 341             fputs("STATE: +media-empty-warning\n", stderr);
 342             _cupsLangPuts(stderr, _("ERROR: Out of paper!\n"));
 343             paperout = 1;
 344           }
 345         }
 346         else if (errno == ENXIO)
 347         {
 348           if (offline != 1)
 349           {
 350             fputs("STATE: +offline-report\n", stderr);
 351             _cupsLangPuts(stderr, _("INFO: Printer is currently off-line.\n"));
 352             offline = 1;
 353           }
 354         }
 355         else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY)
 356         {
 357           fprintf(stderr, _("ERROR: Unable to write print data: %s\n"),
 358                   strerror(errno));
 359           return (-1);
 360         }
 361       }
 362       else
 363       {
 364         if (paperout)
 365         {
 366           fputs("STATE: -media-empty-warning\n", stderr);
 367           paperout = 0;
 368         }
 369
 370         if (offline)
 371         {
 372           fputs("STATE: -offline-report\n", stderr);
 373           _cupsLangPuts(stderr, _("INFO: Printer is now online.\n"));
 374           offline = 0;
 375         }
 376
 377         fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes);
 378
 379         print_bytes -= bytes;
 380         print_ptr   += bytes;
 381         total_bytes += bytes;
 382       }
 383     }
 384
 385    /*
 386     * Do SNMP updates periodically...
 387     */
 388
 389     if (snmp_fd >= 0 && time(&curtime) >= snmp_update)
 390     {
 391       if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL))
 392         snmp_update = INT_MAX;
 393       else
 394         snmp_update = curtime + 5;
 395     }
 396   }
 397
 398  /*
 399   * Return with success...
 400   */
 401
 402   return (total_bytes);
 403 }
 404
 405
 406 /*
 407  * End of "$Id: runloop.c 7895 2008-09-02 19:19:43Z mike $".
 408  */