/* * beh ("Backend Error Handler") wrapper backend to extend the possibilities * of handling errors of backends. * * Copyright 2015 by Till Kamppeter * * This is based on dnssd.c of CUPS * dnssd.c copyright notice is follows: * * Copyright 2008-2015 by Apple Inc. * * These coded instructions, statements, and computer programs are the * property of Apple Inc. and are protected by Federal copyright * law. Distribution and use rights are outlined in the file "COPYING" * which should have been included with this file. */ /* * Include necessary headers. */ #include "backend-private.h" #include #include /* * Local globals... */ static int job_canceled = 0; /* Set to 1 on SIGTERM */ /* * Local functions... */ static int call_backend(char *uri, int argc, char **argv, char *tempfile); static void sigterm_handler(int sig); /* * 'main()' - Browse for printers. */ int /* O - Exit status */ main(int argc, /* I - Number of command-line args */ char *argv[]) { /* I - Command-line arguments */ char *uri, *ptr, *filename; char tmpfilename[1024], buf[8192]; int dd, att, delay, retval; #if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET) struct sigaction action; /* Actions for POSIX signals */ #endif /* HAVE_SIGACTION && !HAVE_SIGSET */ /* * Don't buffer stderr, and catch SIGTERM... */ setbuf(stderr, NULL); #ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */ sigset(SIGTERM, sigterm_handler); #elif defined(HAVE_SIGACTION) memset(&action, 0, sizeof(action)); sigemptyset(&action.sa_mask); action.sa_handler = sigterm_handler; sigaction(SIGTERM, &action, NULL); #else signal(SIGTERM, sigterm_handler); #endif /* HAVE_SIGSET */ /* * Check command-line... */ if (argc == 1) { if ((ptr = strrchr(argv[0], '/')) != NULL) ptr ++; else ptr = argv[0]; printf("network %s \"Unknown\" \"Backend Error Handler\"\n", ptr); return (CUPS_BACKEND_OK); } else if (argc < 6) { fprintf(stderr, "Usage: %s job-id user title copies options [file]\n", argv[0]); return (CUPS_BACKEND_FAILED); } /* * Read out the parameters */ uri = getenv("DEVICE_URI"); if (!uri) { fprintf(stderr, "ERROR: No device URI supplied!"); return (CUPS_BACKEND_FAILED); } ptr = strstr(uri, ":/"); if (!ptr) goto bad_uri; ptr += 2; if (*ptr == '0') dd = 0; else if (*ptr == '1') dd = 1; else goto bad_uri; ptr ++; if (*ptr != '/') goto bad_uri; ptr ++; att = 0; while (isdigit(*ptr)) { att = att * 10 + (int)(*ptr) - 48; ptr ++; } if (*ptr != '/') goto bad_uri; ptr ++; delay = 0; while (isdigit(*ptr)) { delay = delay * 10 + (int)(*ptr) - 48; ptr ++; } if (*ptr != '/') goto bad_uri; ptr ++; fprintf(stderr, "DEBUG: beh: Don't disable: %d; Attempts: %d; Delay: %d; Destination URI: %s\n", dd, att, delay, ptr); /* * If reading from stdin, write everything into a temporary file */ if (argc == 6) { char *tmpdir; int fd; FILE *tmpfile; size_t bytes; tmpdir = getenv("TMPDIR"); if (!tmpdir) tmpdir = "/tmp"; snprintf(tmpfilename, sizeof(tmpfilename), "%s/beh-XXXXXX", tmpdir); fd = mkstemp(tmpfilename); if (fd < 0) { fprintf(stderr, "ERROR: beh: Could not create temporary file: %s\n", strerror(errno)); return (CUPS_BACKEND_FAILED); } tmpfile = fdopen(fd, "r+"); while ((bytes = fread(buf, 1, sizeof(buf), stdin))) fwrite(buf, 1, bytes, tmpfile); fclose(tmpfile); filename = tmpfilename; } else { tmpfilename[0] = '\0'; filename = argv[6]; } /* * Do it! */ while ((retval = call_backend(ptr, argc, argv, filename)) != CUPS_BACKEND_OK && !job_canceled) { if (att > 0) { att --; if (att == 0) break; } if (delay > 0) sleep (delay); } if (strlen(tmpfilename) > 0) unlink(tmpfilename); /* * Return the exit value of the backend only if requested */ if (!dd) return (retval); else return (CUPS_BACKEND_OK); /* * Error handling */ bad_uri: fprintf(stderr, "ERROR: URI must be \"beh:/
///\"!\n"); return (CUPS_BACKEND_FAILED); } /* * 'call_backend()' - Execute the command line of the destination backend */ static int call_backend(char *uri, /* I - URI of final destination */ int argc, /* I - Number of command line arguments */ char **argv, /* I - Command-line arguments */ char *filename) { /* I - File name of input data */ const char *cups_serverbin; /* Location of programs */ char scheme[1024], /* Scheme from URI */ *ptr, /* Pointer into scheme */ cmdline[65536]; /* Backend command line */ int retval; /* * Build the backend command line... */ strncpy(scheme, uri, sizeof(scheme)); if ((ptr = strchr(scheme, ':')) != NULL) *ptr = '\0'; if ((cups_serverbin = getenv("CUPS_SERVERBIN")) == NULL) cups_serverbin = CUPS_SERVERBIN; if (!strncasecmp(uri, "file:", 5) || uri[0] == '/') { fprintf(stderr, "ERROR: beh: Direct output into a file not supported.\n"); exit (CUPS_BACKEND_FAILED); } else snprintf(cmdline, sizeof(cmdline), "%s/backend/%s '%s' '%s' '%s' '%s' '%s' %s", cups_serverbin, scheme, argv[1], argv[2], argv[3], /* Apply number of copies only if beh was called with a file name and not with the print data in stdin, as backends should handle copies only if they are called with a file name */ (argc == 6 ? "1" : argv[4]), argv[5], filename); /* * Overwrite the device URI and run the actual backend... */ setenv("DEVICE_URI", uri, 1); fprintf(stderr, "DEBUG: beh: Executing backend command line \"%s\"...\n", cmdline); fprintf(stderr, "DEBUG: beh: Using device URI: %s\n", uri); retval = system(cmdline) >> 8; if (retval == -1) fprintf(stderr, "ERROR: Unable to execute backend command line: %s\n", strerror(errno)); return (retval); } /* * 'sigterm_handler()' - Handle termination signals. */ static void sigterm_handler(int sig) { /* I - Signal number (unused) */ (void)sig; fprintf(stderr, "DEBUG: beh: Job canceled.\n"); if (job_canceled) _exit(CUPS_BACKEND_OK); else job_canceled = 1; }