1/* 2 * "$Id: runloop.c 11560 2014-02-06 20:10:19Z msweet $" 3 * 4 * Common run loop APIs for CUPS backends. 5 * 6 * Copyright 2007-2014 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 18/* 19 * Include necessary headers. 20 */ 21 22#include "backend-private.h" 23#include <limits.h> 24#include <sys/select.h> 25 26 27/* 28 * 'backendDrainOutput()' - Drain pending print data to the device. 29 */ 30 31int /* O - 0 on success, -1 on error */ 32backendDrainOutput(int print_fd, /* I - Print file descriptor */ 33 int device_fd) /* I - Device file descriptor */ 34{ 35 int nfds; /* Maximum file descriptor value + 1 */ 36 fd_set input; /* Input set for reading */ 37 ssize_t print_bytes, /* Print bytes read */ 38 bytes; /* Bytes written */ 39 char print_buffer[8192], /* Print data buffer */ 40 *print_ptr; /* Pointer into print data buffer */ 41 struct timeval timeout; /* Timeout for read... */ 42 43 44 fprintf(stderr, "DEBUG: backendDrainOutput(print_fd=%d, device_fd=%d)\n", 45 print_fd, device_fd); 46 47 /* 48 * Figure out the maximum file descriptor value to use with select()... 49 */ 50 51 nfds = (print_fd > device_fd ? print_fd : device_fd) + 1; 52 53 /* 54 * Now loop until we are out of data from print_fd... 55 */ 56 57 for (;;) 58 { 59 /* 60 * Use select() to determine whether we have data to copy around... 61 */ 62 63 FD_ZERO(&input); 64 FD_SET(print_fd, &input); 65 66 timeout.tv_sec = 0; 67 timeout.tv_usec = 0; 68 69 if (select(nfds, &input, NULL, NULL, &timeout) < 0) 70 return (-1); 71 72 if (!FD_ISSET(print_fd, &input)) 73 return (0); 74 75 if ((print_bytes = read(print_fd, print_buffer, 76 sizeof(print_buffer))) < 0) 77 { 78 /* 79 * Read error - bail if we don't see EAGAIN or EINTR... 80 */ 81 82 if (errno != EAGAIN || errno != EINTR) 83 { 84 fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno)); 85 _cupsLangPrintFilter(stderr, "ERROR", _("Unable to read print data.")); 86 return (-1); 87 } 88 89 print_bytes = 0; 90 } 91 else if (print_bytes == 0) 92 { 93 /* 94 * End of file, return... 95 */ 96 97 return (0); 98 } 99 100 fprintf(stderr, "DEBUG: Read %d bytes of print data...\n", 101 (int)print_bytes); 102 103 for (print_ptr = print_buffer; print_bytes > 0;) 104 { 105 if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0) 106 { 107 /* 108 * Write error - bail if we don't see an error we can retry... 109 */ 110 111 if (errno != ENOSPC && errno != ENXIO && errno != EAGAIN && 112 errno != EINTR && errno != ENOTTY) 113 { 114 _cupsLangPrintError("ERROR", _("Unable to write print data")); 115 return (-1); 116 } 117 } 118 else 119 { 120 fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes); 121 122 print_bytes -= bytes; 123 print_ptr += bytes; 124 } 125 } 126 } 127} 128 129 130/* 131 * 'backendRunLoop()' - Read and write print and back-channel data. 132 */ 133 134ssize_t /* O - Total bytes on success, -1 on error */ 135backendRunLoop( 136 int print_fd, /* I - Print file descriptor */ 137 int device_fd, /* I - Device file descriptor */ 138 int snmp_fd, /* I - SNMP socket or -1 if none */ 139 http_addr_t *addr, /* I - Address of device */ 140 int use_bc, /* I - Use back-channel? */ 141 int update_state, /* I - Update printer-state-reasons? */ 142 _cups_sccb_t side_cb) /* I - Side-channel callback */ 143{ 144 int nfds; /* Maximum file descriptor value + 1 */ 145 fd_set input, /* Input set for reading */ 146 output; /* Output set for writing */ 147 ssize_t print_bytes, /* Print bytes read */ 148 bc_bytes, /* Backchannel bytes read */ 149 total_bytes, /* Total bytes written */ 150 bytes; /* Bytes written */ 151 int paperout; /* "Paper out" status */ 152 int offline; /* "Off-line" status */ 153 char print_buffer[8192], /* Print data buffer */ 154 *print_ptr, /* Pointer into print data buffer */ 155 bc_buffer[1024]; /* Back-channel data buffer */ 156 struct timeval timeout; /* Timeout for select() */ 157 time_t curtime, /* Current time */ 158 snmp_update = 0; 159#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET) 160 struct sigaction action; /* Actions for POSIX signals */ 161#endif /* HAVE_SIGACTION && !HAVE_SIGSET */ 162 163 164 fprintf(stderr, 165 "DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, snmp_fd=%d, " 166 "addr=%p, use_bc=%d, side_cb=%p)\n", 167 print_fd, device_fd, snmp_fd, addr, use_bc, side_cb); 168 169 /* 170 * If we are printing data from a print driver on stdin, ignore SIGTERM 171 * so that the driver can finish out any page data, e.g. to eject the 172 * current page. We only do this for stdin printing as otherwise there 173 * is no way to cancel a raw print job... 174 */ 175 176 if (!print_fd) 177 { 178#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */ 179 sigset(SIGTERM, SIG_IGN); 180#elif defined(HAVE_SIGACTION) 181 memset(&action, 0, sizeof(action)); 182 183 sigemptyset(&action.sa_mask); 184 action.sa_handler = SIG_IGN; 185 sigaction(SIGTERM, &action, NULL); 186#else 187 signal(SIGTERM, SIG_IGN); 188#endif /* HAVE_SIGSET */ 189 } 190 else if (print_fd < 0) 191 { 192 /* 193 * Copy print data from stdin, but don't mess with the signal handlers... 194 */ 195 196 print_fd = 0; 197 } 198 199 /* 200 * Figure out the maximum file descriptor value to use with select()... 201 */ 202 203 nfds = (print_fd > device_fd ? print_fd : device_fd) + 1; 204 205 /* 206 * Now loop until we are out of data from print_fd... 207 */ 208 209 for (print_bytes = 0, print_ptr = print_buffer, offline = -1, 210 paperout = -1, total_bytes = 0;;) 211 { 212 /* 213 * Use select() to determine whether we have data to copy around... 214 */ 215 216 FD_ZERO(&input); 217 if (!print_bytes) 218 FD_SET(print_fd, &input); 219 if (use_bc) 220 FD_SET(device_fd, &input); 221 if (!print_bytes && side_cb) 222 FD_SET(CUPS_SC_FD, &input); 223 224 FD_ZERO(&output); 225 if (print_bytes || (!use_bc && !side_cb)) 226 FD_SET(device_fd, &output); 227 228 if (use_bc || side_cb) 229 { 230 timeout.tv_sec = 5; 231 timeout.tv_usec = 0; 232 233 if (select(nfds, &input, &output, NULL, &timeout) < 0) 234 { 235 /* 236 * Pause printing to clear any pending errors... 237 */ 238 239 if (errno == ENXIO && offline != 1 && update_state) 240 { 241 fputs("STATE: +offline-report\n", stderr); 242 _cupsLangPrintFilter(stderr, "INFO", 243 _("The printer is not connected.")); 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 if ((*side_cb)(print_fd, device_fd, snmp_fd, addr, use_bc)) 270 side_cb = NULL; 271 continue; 272 } 273 274 /* 275 * Check if we have back-channel data ready... 276 */ 277 278 if (FD_ISSET(device_fd, &input)) 279 { 280 if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0) 281 { 282 fprintf(stderr, 283 "DEBUG: Received " CUPS_LLFMT " bytes of back-channel data\n", 284 CUPS_LLCAST bc_bytes); 285 cupsBackChannelWrite(bc_buffer, (size_t)bc_bytes, 1.0); 286 } 287 else if (bc_bytes < 0 && errno != EAGAIN && errno != EINTR) 288 { 289 fprintf(stderr, "DEBUG: Error reading back-channel data: %s\n", 290 strerror(errno)); 291 use_bc = 0; 292 } 293 else if (bc_bytes == 0) 294 use_bc = 0; 295 } 296 297 /* 298 * Check if we have print data ready... 299 */ 300 301 if (FD_ISSET(print_fd, &input)) 302 { 303 if ((print_bytes = read(print_fd, print_buffer, 304 sizeof(print_buffer))) < 0) 305 { 306 /* 307 * Read error - bail if we don't see EAGAIN or EINTR... 308 */ 309 310 if (errno != EAGAIN || errno != EINTR) 311 { 312 fprintf(stderr, "DEBUG: Read failed: %s\n", strerror(errno)); 313 _cupsLangPrintFilter(stderr, "ERROR", 314 _("Unable to read print data.")); 315 return (-1); 316 } 317 318 print_bytes = 0; 319 } 320 else if (print_bytes == 0) 321 { 322 /* 323 * End of file, break out of the loop... 324 */ 325 326 break; 327 } 328 329 print_ptr = print_buffer; 330 331 fprintf(stderr, "DEBUG: Read %d bytes of print data...\n", 332 (int)print_bytes); 333 } 334 335 /* 336 * Check if the device is ready to receive data and we have data to 337 * send... 338 */ 339 340 if (print_bytes && FD_ISSET(device_fd, &output)) 341 { 342 if ((bytes = write(device_fd, print_ptr, (size_t)print_bytes)) < 0) 343 { 344 /* 345 * Write error - bail if we don't see an error we can retry... 346 */ 347 348 if (errno == ENOSPC) 349 { 350 if (paperout != 1 && update_state) 351 { 352 fputs("STATE: +media-empty-warning\n", stderr); 353 fputs("DEBUG: Out of paper\n", stderr); 354 paperout = 1; 355 } 356 } 357 else if (errno == ENXIO) 358 { 359 if (offline != 1 && update_state) 360 { 361 fputs("STATE: +offline-report\n", stderr); 362 _cupsLangPrintFilter(stderr, "INFO", 363 _("The printer is not connected.")); 364 offline = 1; 365 } 366 } 367 else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY) 368 { 369 _cupsLangPrintError("ERROR", _("Unable to write print data")); 370 return (-1); 371 } 372 } 373 else 374 { 375 if (paperout && update_state) 376 { 377 fputs("STATE: -media-empty-warning\n", stderr); 378 paperout = 0; 379 } 380 381 if (offline && update_state) 382 { 383 fputs("STATE: -offline-report\n", stderr); 384 _cupsLangPrintFilter(stderr, "INFO", 385 _("The printer is now connected.")); 386 offline = 0; 387 } 388 389 fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes); 390 391 print_bytes -= bytes; 392 print_ptr += bytes; 393 total_bytes += bytes; 394 } 395 } 396 397 /* 398 * Do SNMP updates periodically... 399 */ 400 401 if (snmp_fd >= 0 && time(&curtime) >= snmp_update) 402 { 403 if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL)) 404 snmp_update = INT_MAX; 405 else 406 snmp_update = curtime + 5; 407 } 408 } 409 410 /* 411 * Return with success... 412 */ 413 414 return (total_bytes); 415} 416 417 418/* 419 * 'backendWaitLoop()' - Wait for input from stdin while handling side-channel 420 * queries. 421 */ 422 423int /* O - 1 if data is ready, 0 if not */ 424backendWaitLoop( 425 int snmp_fd, /* I - SNMP socket or -1 if none */ 426 http_addr_t *addr, /* I - Address of device */ 427 int use_bc, /* I - Use back-channel? */ 428 _cups_sccb_t side_cb) /* I - Side-channel callback */ 429{ 430 int nfds; /* Number of file descriptors */ 431 fd_set input; /* Input set for reading */ 432 time_t curtime = 0, /* Current time */ 433 snmp_update = 0;/* Last SNMP status update */ 434 struct timeval timeout; /* Timeout for select() */ 435 436 437 fprintf(stderr, "DEBUG: backendWaitLoop(snmp_fd=%d, addr=%p, side_cb=%p)\n", 438 snmp_fd, addr, side_cb); 439 440 /* 441 * Now loop until we receive data from stdin... 442 */ 443 444 if (snmp_fd >= 0) 445 snmp_update = time(NULL) + 5; 446 447 for (;;) 448 { 449 /* 450 * Use select() to determine whether we have data to copy around... 451 */ 452 453 FD_ZERO(&input); 454 FD_SET(0, &input); 455 if (side_cb) 456 FD_SET(CUPS_SC_FD, &input); 457 458 if (snmp_fd >= 0) 459 { 460 curtime = time(NULL); 461 timeout.tv_sec = curtime >= snmp_update ? 0 : snmp_update - curtime; 462 timeout.tv_usec = 0; 463 464 nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, &timeout); 465 } 466 else 467 nfds = select(CUPS_SC_FD + 1, &input, NULL, NULL, NULL); 468 469 if (nfds < 0) 470 { 471 /* 472 * Pause printing to clear any pending errors... 473 */ 474 475 if (errno == EINTR) 476 { 477 fputs("DEBUG: Received an interrupt before any bytes were " 478 "written, aborting.\n", stderr); 479 return (0); 480 } 481 482 sleep(1); 483 continue; 484 } 485 486 /* 487 * Check for input on stdin... 488 */ 489 490 if (FD_ISSET(0, &input)) 491 break; 492 493 /* 494 * Check if we have a side-channel request ready... 495 */ 496 497 if (side_cb && FD_ISSET(CUPS_SC_FD, &input)) 498 { 499 /* 500 * Do the side-channel request, then start back over in the select 501 * loop since it may have read from print_fd... 502 */ 503 504 if ((*side_cb)(0, -1, snmp_fd, addr, use_bc)) 505 side_cb = NULL; 506 continue; 507 } 508 509 /* 510 * Do SNMP updates periodically... 511 */ 512 513 if (snmp_fd >= 0 && curtime >= snmp_update) 514 { 515 if (backendSNMPSupplies(snmp_fd, addr, NULL, NULL)) 516 snmp_fd = -1; 517 else 518 snmp_update = curtime + 5; 519 } 520 } 521 522 /* 523 * Return with success... 524 */ 525 526 return (1); 527} 528 529 530/* 531 * End of "$Id: runloop.c 11560 2014-02-06 20:10:19Z msweet $". 532 */ 533