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cups-failover-backend.patch
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cups-failover-backend.patch
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diff -up cups-2.4.0/backend/failover.c.failover cups-2.4.0/backend/failover.c
--- cups-2.4.0/backend/failover.c.failover 2021-12-15 11:06:14.274967317 +0100
+++ cups-2.4.0/backend/failover.c 2021-12-15 11:06:14.274967317 +0100
@@ -0,0 +1,837 @@
+/*
+ * Failover Backend for the Common UNIX Printing System (CUPS).
+ *
+ * Copyright (c) 2014, Red Hat, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * * Neither the name of Red Hat, Inc. nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT,
+ * INC. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * Original version by Clark Hale, Red Hat, Inc.
+ *
+ * This backend presents a fake printer that will choose the first
+ * available printer from a list of IPP URIs.
+ *
+ * Option failover contains a comma separated list of IPP URIs. The
+ * URIs are attempted in-order.
+ *
+ * Option failover-retries contains an integer that indicates how many
+ * times to iterate through the failover list before completely
+ * failing.
+ *
+ * Contents:
+ * main() - Checks each printer in a failover list, and
+ * sends job data to the first available printer
+ * move_job() - Sends and IPP Move-Job request
+ * check_printer() - Checks a printer's attributes to see
+ * if it's enabled and accepting jobs
+ * read_config() - Read the backends configuration from
+ * options
+ * get_printer_attributes() - Sends an IPP Get-Attributes request to
+ * a URI
+ * sigterm_handler() - Handle SIGTERM that cancels the job
+ * password_cb() - Password call back used to disable password
+ * prompt
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <cups/http-private.h>
+#include <cups/http.h>
+#include "backend-private.h"
+
+/*
+ * Return Values
+ */
+typedef enum fo_state_e
+{
+ FO_PRINTER_GOOD = 0,
+ FO_PRINTER_BAD,
+ FO_PRINTER_BUSY,
+ FO_AUTH_REQUIRED
+} fo_state_t;
+
+/*
+ * Constants
+ */
+#define FAILOVER_DEFAULT_RETRIES (3)
+#define FAILOVER_PASSWORD_RETRIES_MAX (3)
+
+/*
+ * Local Functions
+ */
+static int check_printer(const char *device_uri);
+static int read_config(cups_array_t *printer_array, int *retries,
+ const char *options);
+static int get_printer_attributes(const char *device_uri,
+ ipp_t **attributes);
+static int move_job(int jobid, const char *dest);
+static void sigterm_handler(int sig);
+static const char *password_cb(const char *);
+
+/*
+ * Global Variables
+ */
+static int job_canceled = 0; /* Job canceled */
+static char *password = NULL; /* password for device */
+static int password_retries = 0;
+static const char *auth_info_required = "none";
+
+/*
+ * 'main()' - Checks each printer in a failover list, and
+ * sends job data to the first available printer
+ * Usage:
+ * printer-uri job-id user title copies options [file]
+ *
+ * The printer-uri option is not used, but it still required to fit
+ * to the backend(7) standards.
+ */
+int
+main(int argc, char *argv[])
+{
+ const char *selected_uri = NULL; /* URI of selected printer */
+ const char *tmp_device_uri; /* Device URI to check */
+ cups_array_t *printer_array; /* Array of available printers */
+ int printer_count = 0; /* current printer array index */
+ int retry_max = 1; /* maximum retries before exit */
+ int retry_count = 0; /* current retry number */
+ int auth_failed_count = 0; /* auth failures per loop */
+ int rc = CUPS_BACKEND_OK;
+#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
+ struct sigaction action; /* Actions for POSIX signals */
+#endif /* HAVE_SIGACTION && !HAVE_SIGSET */
+
+ /*
+ * Check args
+ */
+ if (argc == 1)
+ {
+ /*
+ * print out discovery data
+ */
+ char *backendName;
+
+ if ((backendName = strrchr(argv[0], '/')) != NULL)
+ backendName++;
+ else
+ backendName = argv[0];
+
+ _cupsLangPrintf(stderr,"network %s \"Unknown\" \"%s (%s)\"\n",
+ backendName,
+ _cupsLangString(cupsLangDefault(), _("Failover Printer")),
+ backendName);
+
+ return (CUPS_BACKEND_OK);
+ }
+ else if (argc < 6)
+ {
+ _cupsLangPrintf(stderr,
+ _("Usage: %s job-id user title copies options [file]"),
+ argv[0]);
+ return (CUPS_BACKEND_STOP);
+ }
+
+ fprintf(stderr, "DEBUG: Failover backend starting up.\n");
+
+ /*
+ * Don't buffer status messages
+ */
+ setbuf(stderr, NULL);
+
+ /*
+ * Ignore SIGPIPE and catch SIGTERM signals...
+ */
+#ifdef HAVE_SIGSET
+ sigset(SIGPIPE, SIG_IGN);
+ sigset(SIGTERM, sigterm_handler);
+#elif defined(HAVE_SIGACTION)
+ memset(&action, 0, sizeof(action));
+ action.sa_handler = SIG_IGN;
+ sigaction(SIGPIPE, &action, NULL);
+
+ sigemptyset(&action.sa_mask);
+ sigaddset(&action.sa_mask, SIGTERM);
+ action.sa_handler = sigterm_handler;
+ sigaction(SIGTERM, &action, NULL);
+#else
+ signal(SIGPIPE, SIG_IGN);
+ signal(SIGTERM, sigterm_handler);
+#endif /* HAVE_SIGSET */
+
+ printer_array = cupsArrayNew(NULL, NULL);
+
+ /*
+ * Read Configuration
+ */
+ if ((rc = read_config(printer_array, &retry_max,
+ argv[5])) != CUPS_BACKEND_OK)
+ {
+ fprintf(stderr, "ERROR: Failed to read configuration options!\n");
+ goto cleanup;
+ }
+
+ /*
+ * Main Retry Loop
+ */
+ for (retry_count = 0; retry_count < retry_max; retry_count++)
+ {
+ fprintf(stderr, "DEBUG: Retry loop #%d\n", retry_count + 1);
+
+ /*
+ * Reset Counters
+ */
+ printer_count = 0;
+ auth_failed_count = 0;
+
+ tmp_device_uri = (char *)cupsArrayFirst(printer_array);
+
+ do
+ {
+ if (job_canceled)
+ {
+ fprintf(stderr, "DEBUG: Job Canceled\n");
+ goto cleanup;
+ }
+
+ fprintf(stderr,"DEBUG: Checking printer #%d: %s\n",
+ printer_count+1, tmp_device_uri);
+
+ rc = check_printer(tmp_device_uri);
+
+ // Printer is available and not busy.
+ if ( rc == FO_PRINTER_GOOD )
+ {
+ selected_uri = tmp_device_uri;
+ break;
+ }
+ // Printer is busy
+ else if (rc == FO_PRINTER_BUSY)
+ {
+ fprintf(stderr, "DEBUG: Waiting for job to complete.\n");
+ sleep(2);
+ continue;
+ }
+ // Authorization is required to access the printer.
+ else if (rc == FO_AUTH_REQUIRED)
+ {
+ auth_failed_count++;
+ fprintf(stderr, "DEBUG: auth_failed_count = %d\n", auth_failed_count);
+ }
+ // Printer is stopped or not accepting jobs
+ else
+ {
+ if (!printer_count)
+ fprintf(stderr, "INFO: Primary Printer, %s, not available. "
+ "Attempting Failovers...\n",
+ tmp_device_uri);
+ else
+ fprintf(stderr, "INFO: Failover Printer, %s, not available. "
+ "Attempting Failovers..\n",
+ tmp_device_uri);
+ printer_count++;
+ tmp_device_uri = (char *)cupsArrayNext(printer_array);
+ }
+ } while (tmp_device_uri != NULL);
+
+ if (selected_uri && !printer_count)
+ fprintf(stderr, "STATE: -primary-printer-failed\n");
+ else
+ fprintf(stderr, "STATE: +primary-printer-failed\n");
+
+ if (job_canceled)
+ {
+ fprintf(stderr, "DEBUG: Job Canceled\n");
+ goto cleanup;
+ }
+
+ if (!selected_uri && auth_failed_count == printer_count)
+ {
+ fprintf(stderr, "ERROR: All failover printers failed with "
+ "authorization issues.\n");
+ rc = CUPS_BACKEND_AUTH_REQUIRED;
+ fprintf(stderr, "ATTR: auth-info-required=%s\n", auth_info_required);
+ goto cleanup;
+ }
+ else if (!selected_uri && retry_count + 1 < retry_max)
+ {
+ fprintf(stderr, "INFO: No suitable printer found...retrying...\n");
+ sleep(2);
+ continue;
+ }
+ else if (selected_uri)
+ {
+ fprintf(stderr, "DEBUG: Using printer, %s.\n", selected_uri);
+ break;
+ }
+ }
+
+ if (!selected_uri)
+ {
+ fprintf(stderr, "ERROR: No suitable printer found. Aborting print\n");
+ rc = CUPS_BACKEND_FAILED;
+ goto cleanup;
+ }
+
+ rc = move_job(atoi(argv[1]), selected_uri);
+
+ if (job_canceled)
+ rc = CUPS_BACKEND_OK;
+
+cleanup :
+ if (job_canceled)
+ rc = CUPS_BACKEND_OK;
+
+ tmp_device_uri = (char *)cupsArrayFirst(printer_array);
+ do
+ {
+ free((void *)tmp_device_uri);
+ } while ((tmp_device_uri = (char *)cupsArrayNext(printer_array)) != NULL);
+
+ cupsArrayDelete(printer_array);
+ sleep(2);
+ return (rc);
+}
+
+/*
+ * 'check_printer()' - Checks the status of a remote printer and returns
+ * back a good/bad/busy status.
+ */
+int
+check_printer(const char *device_uri)
+{
+ ipp_t *attributes = NULL; /* attributes for device_uri */
+ ipp_attribute_t *tmp_attribute; /* for examining attribs */
+ int rc = FO_PRINTER_GOOD; /* return code */
+ char *reason; /* printer state reason */
+ int i;
+
+ fprintf(stderr, "DEBUG: Checking printer %s\n",device_uri);
+
+ rc = get_printer_attributes(device_uri, &attributes);
+ if ( rc != CUPS_BACKEND_OK )
+ {
+ fprintf(stderr, "DEBUG: Failed to get attributes from printer: %s\n",
+ device_uri);
+ if ( rc == CUPS_BACKEND_AUTH_REQUIRED )
+ return (FO_AUTH_REQUIRED);
+ else
+ return (FO_PRINTER_BAD);
+ }
+
+ /*
+ * Check if printer is accepting jobs
+ */
+ if ((tmp_attribute = ippFindAttribute(attributes,
+ "printer-is-accepting-jobs",
+ IPP_TAG_BOOLEAN)) != NULL &&
+ !tmp_attribute->values[0].boolean)
+ {
+ fprintf(stderr,
+ "DEBUG: Printer, %s, is not accepting jobs.\n",
+ device_uri);
+
+ rc = FO_PRINTER_BAD;
+ }
+
+ /*
+ * Check if printer is stopped or busy processing
+ */
+ if ((tmp_attribute = ippFindAttribute(attributes,
+ "printer-state",
+ IPP_TAG_ENUM)) != NULL)
+ {
+ // Printer Stopped
+ if ( tmp_attribute->values[0].integer == IPP_PRINTER_STOPPED )
+ {
+ fprintf(stderr, "DEBUG: Printer, %s, stopped.\n", device_uri);
+ rc = FO_PRINTER_BAD;
+ }
+ // Printer Busy
+ else if ( tmp_attribute->values[0].integer == IPP_PRINTER_PROCESSING )
+ {
+ fprintf(stderr, "DEBUG: Printer %s is busy.\n", device_uri);
+ rc = FO_PRINTER_BUSY;
+ }
+ }
+
+ /*
+ * Parse through the printer-state-reasons
+ */
+ if ((tmp_attribute = ippFindAttribute(attributes, "printer-state-reasons",
+ IPP_TAG_KEYWORD)) != NULL)
+ {
+ for (i = 0; i < tmp_attribute->num_values; i++)
+ {
+ reason = tmp_attribute->values[i].string.text;
+ int len = strlen(reason);
+
+ if (len > 8 && !strcmp(reason + len - 8, "-warning"))
+ {
+ fprintf(stderr, "DEBUG: Printer Supply Warning, %s\n", reason);
+ rc = FO_PRINTER_BAD;
+ }
+ else if (len > 6 && !strcmp(reason + len - 6, "-error"))
+ {
+ fprintf(stderr, "DEBUG: Printer Supply Error, %s\n", reason);
+ rc = FO_PRINTER_BAD;
+ }
+ }
+ }
+
+ return (rc);
+}
+
+/*
+ * 'read_config()' - Parses the failover and failover-retries options
+ *
+ */
+static int
+read_config(cups_array_t *printer_array, int *retries, const char *options)
+{
+
+ const char *tmp; /* temporary ptr */
+ char *tok_tmp; /* temporary ptr for option parsing */
+ int jobopts_count = 0; /* number of options */
+ cups_option_t *jobopts = NULL; /* job options */
+
+
+ fprintf(stderr, "DEBUG: Reading Configuration.\n");
+ jobopts_count = cupsParseOptions(options, 0, &jobopts);
+
+ if (!jobopts_count)
+ {
+ fprintf(stderr,
+ "ERROR: No job options! Cannot find failover options!\n");
+ return (CUPS_BACKEND_STOP);
+ }
+
+ /*
+ * Get attributes from the primary printer
+ */
+ fprintf(stderr, "DEBUG: Searching for failover option.\n");
+
+ if ((tmp = cupsGetOption("failover", jobopts_count, jobopts)) != NULL)
+ {
+ fprintf(stderr, "DEBUG: Failover option contents: %s.\n", tmp);
+
+ tok_tmp = strdup(tmp);
+
+ tmp = strtok(tok_tmp, ",");
+ do
+ {
+ cupsArrayAdd(printer_array, strdup(tmp));
+ } while ((tmp = strtok(NULL,",")) != NULL);
+
+ free(tok_tmp);
+ }
+ else
+ {
+ /*
+ * The queue is misconfigured, so return back CUPS_BACKEND_STOP
+ */
+ fprintf(stderr, "ERROR: failover option not specified!\n");
+ return (CUPS_BACKEND_STOP);
+ }
+
+ /*
+ * Get the failover-retries value, if it exists.
+ */
+ fprintf(stderr, "DEBUG: Searching for failover-retries option.\n");
+
+ if ((tmp = cupsGetOption("failover-retries",
+ jobopts_count, jobopts)) != NULL)
+ {
+ fprintf(stderr, "DEBUG: failover-retries option contents: %s.\n", tmp);
+ *retries = atoi(tmp);
+ }
+ else
+ {
+ *retries = FAILOVER_DEFAULT_RETRIES;
+ fprintf(stderr, "DEBUG: Failed to get failover-retries option\n");
+ fprintf(stderr, "DEBUG: Defaulted to %d retries\n", *retries);
+ }
+
+ return (CUPS_BACKEND_OK);
+}
+
+/*
+ * 'get_printer_attributes()' - Sends an IPP Get-Attributes request to
+ * a URI
+ */
+int
+get_printer_attributes(const char *device_uri, ipp_t **attributes)
+{
+ char uri[HTTP_MAX_URI]; /* Updated URI without login */
+ int version; /* IPP version */
+ char scheme[256]; /* Scheme in URI */
+ ipp_status_t ipp_status; /* Status of IPP request */
+ char hostname[1024]; /* Hostname */
+ char resource[1024]; /* Resource infoo */
+ char addrname[256]; /* Address name */
+ int port; /* IPP Port number */
+ char portname[255]; /* Port as string */
+ http_t *http; /* HTTP connection */
+ ipp_t *request; /* IPP request */
+ int rc = CUPS_BACKEND_OK; /* Return Code */
+ char username[256]; /* Username for device URI */
+ char *option_ptr; /* for parsing resource opts */
+ const char * const pattrs[] = /* Printer attributes wanted */
+ {
+ "printer-is-accepting-jobs",
+ "printer-state",
+ "printer-state-reasons"
+ };
+
+ if (job_canceled)
+ return (CUPS_BACKEND_OK);
+
+ fprintf(stderr, "DEBUG: Getting Printer Attributes.\n");
+ fprintf(stderr, "DEBUG: Device URL %s.\n", device_uri);
+
+ /*
+ * Parse device_uri
+ */
+ if (httpSeparateURI(HTTP_URI_CODING_ALL, device_uri, scheme, sizeof(scheme),
+ username, sizeof(username), hostname, sizeof(hostname),
+ &port, resource, sizeof(resource)) != HTTP_URI_OK)
+ {
+ fprintf(stderr, "ERROR: Problem parsing device_uri, %s\n", device_uri);
+ return (CUPS_BACKEND_STOP);
+ }
+
+ if (!port)
+ port = IPP_PORT;
+
+ sprintf(portname, "%d", port);
+
+ fprintf(stderr, "DEBUG: Getting Printer Attributes.\n");
+
+ /*
+ * Configure password
+ */
+ cupsSetPasswordCB(password_cb);
+
+ /*
+ * reset, in case a previous attempt for
+ * another printer left residue
+ */
+ cupsSetUser(NULL);
+ password = NULL;
+ password_retries = 0;
+
+ if (*username)
+ {
+ if ((password = strchr(username, ':')) != NULL)
+ {
+ *password = '\0';
+ password++;
+ }
+
+ cupsSetUser(username);
+ }
+ else if (!getuid())
+ {
+ const char *username_env;
+
+ if ((username_env = getenv("AUTH_USERNAME")) != NULL)
+ {
+ cupsSetUser(username_env);
+ password = getenv("AUTH_PASSWORD");
+ }
+ }
+
+ /*
+ * Try connecting to the remote server...
+ */
+ fprintf(stderr, "DEBUG: Connecting to %s:%d\n", hostname, port);
+ _cupsLangPuts(stderr, _("INFO: Connecting to printer...\n"));
+
+ http = httpConnectEncrypt(hostname, port, cupsEncryption());
+
+ /*
+ * Deal the socket not being open.
+ */
+ if (!http)
+ {
+ int error = errno; /* Connection error */
+
+ switch (error)
+ {
+ case EHOSTDOWN :
+ _cupsLangPuts(stderr, _("WARNING: "
+ "The printer may not exist or "
+ "is unavailable at this time.\n"));
+ break;
+ case EHOSTUNREACH :
+ _cupsLangPuts(stderr, _("WARNING: "
+ "The printer is unreachable at this "
+ "time.\n"));
+ break;
+ case ECONNREFUSED :
+ _cupsLangPuts(stderr, _("WARNING: "
+ "Connection Refused.\n"));
+ break;
+ default :
+ fprintf(stderr, "DEBUG: Connection error: %s\n", strerror(errno));
+ break;
+ }
+
+ rc = CUPS_BACKEND_FAILED;
+ sleep(5);
+ goto prt_available_cleanup;
+ }
+
+
+#ifdef AF_INET6
+ if (http->hostaddr->addr.sa_family == AF_INET6)
+ fprintf(stderr, "DEBUG: Connected to [%s]:%d (IPv6)...\n",
+ httpAddrString(http->hostaddr, addrname, sizeof(addrname)),
+ ntohs(http->hostaddr->ipv6.sin6_port));
+ else
+#endif /* AF_INET6 */
+ if (http->hostaddr->addr.sa_family == AF_INET)
+ fprintf(stderr, "DEBUG: Connected to %s:%d (IPv4)...\n",
+ httpAddrString(http->hostaddr, addrname, sizeof(addrname)),
+ ntohs(http->hostaddr->ipv4.sin_port));
+
+ /*
+ * Search the resource string for options.
+ * We only care about version, for the moment.
+ */
+ version = 11;
+
+ if ((option_ptr = strchr(resource, '?')) != NULL)
+ {
+ *option_ptr++ = '\0';
+
+ if ((option_ptr = strstr(option_ptr, "version="))!=NULL)
+ {
+ int minor; /* minor version from URI */
+ int major; /* major version from URI */
+ char *version_str; /* ipp version */
+
+ option_ptr += 8;
+ version_str = option_ptr;
+
+ while (*option_ptr && *option_ptr != '&' && *option_ptr != '+')
+ option_ptr++;
+
+ if (*option_ptr)
+ *option_ptr = '\0';
+
+ sscanf(version_str, "%d.%d", &major, &minor);
+
+ version = (major * 10) + minor;
+
+ switch(version)
+ {
+ case 10 :
+ case 11 :
+ case 20 :
+ case 21 :
+ fprintf(stderr,
+ "DEBUG: Set version to %d from URI\n",
+ version);
+ break;
+ default :
+ _cupsLangPrintf(stderr,
+ _("DEBUG: Invalid version, %d, from URI. "
+ "Using default of 1.1 \n"),
+ version);
+ version = 11;
+ }
+ }
+ }
+
+
+ /*
+ * Build a URI for the printer. We can't use the URI in argv[0]
+ * because it might contain username:password information...
+ */
+ if (httpAssembleURI(HTTP_URI_CODING_ALL, uri, sizeof(uri), scheme, NULL,
+ hostname, port, resource) != HTTP_URI_OK)
+ {
+ fprintf(stderr, "ERROR: Problem assembling printer URI from host %s, "
+ "port %d, resource %s\n", hostname, port, resource);
+ return (CUPS_BACKEND_STOP);
+ }
+
+ /*
+ * Build the IPP request...
+ */
+ request = ippNewRequest(IPP_GET_PRINTER_ATTRIBUTES);
+ request->request.op.version[0] = version / 10;
+ request->request.op.version[1] = version % 10;
+
+ ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri",
+ NULL, uri);
+
+ ippAddStrings(request, IPP_TAG_OPERATION, IPP_TAG_KEYWORD,
+ "requested-attributes", sizeof(pattrs) / sizeof(pattrs[0]),
+ NULL, pattrs);
+
+ /*
+ * Do the request...
+ */
+ fputs("DEBUG: Getting supported attributes...\n", stderr);
+
+ fprintf(stderr, "DEBUG: IPP Request Structure Built.\n");
+
+ *attributes = cupsDoRequest(http, request, resource);
+ ipp_status = cupsLastError();
+
+ fprintf(stderr, "DEBUG: Get-Printer-Attributes: %s (%s)\n",
+ ippErrorString(ipp_status), cupsLastErrorString());
+
+ if (ipp_status > IPP_OK_CONFLICT)
+ {
+ fprintf(stderr, "DEBUG: Get-Printer-Attributes returned %s.\n",
+ ippErrorString(ipp_status));
+ switch(ipp_status)
+ {
+ case IPP_FORBIDDEN :
+ case IPP_NOT_AUTHORIZED :
+ _cupsLangPuts(stderr, _("ERROR: Not Authorized.\n"));
+ rc = CUPS_BACKEND_AUTH_REQUIRED;
+ break;
+ case IPP_PRINTER_BUSY :
+ case IPP_SERVICE_UNAVAILABLE :
+ _cupsLangPuts(stderr, _("ERROR: "
+ "The printer is not responding.\n"));
+ rc = CUPS_BACKEND_FAILED;
+ break;
+ case IPP_BAD_REQUEST :
+ case IPP_VERSION_NOT_SUPPORTED :
+ fprintf(stderr, "ERROR: Destination does not support IPP version %d\n",
+ version);
+ case IPP_NOT_FOUND :
+ _cupsLangPuts(stderr, _("ERROR: "
+ "The printer configuration is incorrect or the "
+ "printer no longer exists.\n"));
+ rc = CUPS_BACKEND_STOP;
+ break;
+ default :
+ rc = CUPS_BACKEND_FAILED;
+ }
+ goto prt_available_cleanup;
+ }
+
+prt_available_cleanup :
+ httpClose(http);
+ return (rc);
+}
+
+static int
+move_job(int jobid, /* Job ID */
+ const char *dest) /* Destination ipp address */
+{
+ ipp_t *request; /* IPP Request */
+ char job_uri[HTTP_MAX_URI]; /* job-uri */
+
+ http_t* http = httpConnectEncrypt(cupsServer(), ippPort(), cupsEncryption());
+
+ if (!http)
+ {
+ _cupsLangPrintf(stderr,
+ _("failover: Unable to connect to server: %s\n"),
+ strerror(errno));
+ return (CUPS_BACKEND_FAILED);
+ }
+
+ /*
+ * Build a CUPS_MOVE_JOB request, which requires the following
+ * attributes:
+ *
+ * job-uri/printer-uri
+ * job-printer-uri
+ * requesting-user-name
+ */
+
+ request = ippNewRequest(CUPS_MOVE_JOB);
+
+ snprintf(job_uri, sizeof(job_uri), "ipp://localhost/jobs/%d", jobid);
+ ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "job-uri", NULL,
+ job_uri);
+
+ ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_NAME,
+ "requesting-user-name",
+ NULL, cupsUser());
+
+ ippAddString(request, IPP_TAG_JOB, IPP_TAG_URI, "job-printer-uri",
+ NULL, dest);
+
+ /*
+ * Do the request and get back a response...
+ */
+
+ ippDelete(cupsDoRequest(http, request, "/jobs"));
+
+ httpClose(http);
+
+ if (cupsLastError() > IPP_OK_CONFLICT)
+ {
+ _cupsLangPrintf(stderr, "failover: %s\n", cupsLastErrorString());
+ return (CUPS_BACKEND_FAILED);
+ }
+ else
+ return (CUPS_BACKEND_OK);
+}
+
+/*
+ * 'sigterm_handler()' - handles a sigterm, i.e. job canceled
+ */
+static void
+sigterm_handler(int sig)
+{
+ if (!job_canceled)
+ {
+ write(2, "DEBUG: Got SIGTERM.\n", 20);
+ job_canceled = 1;
+ }
+ else
+ {
+ /*
+ * Job has already been canceled, so just exit
+ */
+ exit(1);
+ }
+}
+
+/*
+ * 'password_cb()' - Disable the password prompt for cupsDoFileRequest().
+ */
+static const char * /* O - Password */
+password_cb(const char *prompt) /* I - Prompt (not used) */
+{
+ auth_info_required = "username,password";
+ password_retries++;
+
+ if(password_retries < FAILOVER_PASSWORD_RETRIES_MAX)
+ return (password);
+ else
+ return (NULL);
+}
diff -up cups-2.4.0/backend/Makefile.failover cups-2.4.0/backend/Makefile
--- cups-2.4.0/backend/Makefile.failover 2021-11-29 15:27:31.000000000 +0100
+++ cups-2.4.0/backend/Makefile 2021-12-15 11:08:27.433009704 +0100
@@ -25,6 +25,7 @@ RBACKENDS = \
ipp \
lpd \
usb \
+ failover \
$(DNSSD_BACKEND)
UBACKENDS = \
snmp \
@@ -45,6 +46,7 @@ LIBOBJS = \
OBJS = \
ipp.o \
lpd.o \
+ failover.o \
dnssd.o \
snmp.o \
socket.o \
@@ -264,6 +266,15 @@ lpd: lpd.o ../cups/$(LIBCUPS) libbackend
#
+# failover
+#
+
+failover: failover.o ../cups/$(LIBCUPS) libbackend.a
+ echo Linking $@...
+ $(LD_CC) $(ALL_LDFLAGS) -o failover failover.o libbackend.a $(LINKCUPS)
+
+
+#
# snmp
#