net-print/cups/files/cups-2.1.4-ippusb-query.patch

From 2648d4aee3aa7d473fad9b20c4a944cf865e4d80 Mon Sep 17 00:00:00 2001
From: David Valleau <valleau@chromium.org>
Date: Wed, 8 Nov 2017 11:22:05 -0800
Subject: [PATCH] Adding ippusb query path to cups

---
 backend/ipp.c         |  26 +++++++
 cups/Makefile         |   6 +-
 cups/ippusb-private.h |  34 ++++++++
 cups/ippusb.c         | 211 ++++++++++++++++++++++++++++++++++++++++++++++++++
 systemv/lpadmin.c     |  57 ++++++++++++--
 5 files changed, 327 insertions(+), 7 deletions(-)
 create mode 100644 cups/ippusb-private.h
 create mode 100644 cups/ippusb.c

diff --git a/backend/ipp.c b/backend/ipp.c
index 69970a2..47e5faf 100644
--- a/backend/ipp.c
+++ b/backend/ipp.c
@@ -21,6 +21,7 @@
 
 #include "backend-private.h"
 #include <cups/array-private.h>
+#include <cups/ippusb-private.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
@@ -666,6 +667,31 @@ main(int  argc,				/* I - Number of command-line args */
   update_reasons(NULL, "+connecting-to-device");
   fprintf(stderr, "DEBUG: Looking up \"%s\"...\n", hostname);
 
+  // If the scheme is ippusb then a query is sent to the ippusb_manager service
+  // to check if the printer is currently connected and get the name of the
+  // socket used for communication with the printer.
+  if (!strcmp(scheme, "ippusb")) {
+    int sock = open_ippusb_manager_socket();
+    char* response = query_ippusb_manager(sock, hostname);
+
+    close(sock);
+
+    int ret = snprintf(hostname, sizeof(hostname), "/run/ippusb/%s", response);
+    if (ret < 0 || ret >= sizeof(hostname)) {
+      fprintf(stderr, "ERROR: Failed to overwrite hostname");
+      _exit(1);
+    }
+
+    free(response);
+
+    // Change the scheme back to ipp so that communications will be understood
+    // by the printer.
+    strcpy(scheme, "ipp");
+
+    // Wait a maximum of 3 seconds for the socket to be created.
+    wait_for_socket(hostname, 3);
+  }
+
   while ((addrlist = httpAddrGetList(hostname, AF_UNSPEC, portname)) == NULL)
   {
     _cupsLangPrintFilter(stderr, "INFO",
diff --git a/cups/Makefile b/cups/Makefile
index 7b65214..b9f1133 100644
--- a/cups/Makefile
+++ b/cups/Makefile
@@ -79,7 +79,8 @@ LIBOBJS	=	\
 		tls.o \
 		transcode.o \
 		usersys.o \
-		util.o
+		util.o \
+		ippusb.o
 TESTOBJS	= \
 		testadmin.o \
 		testarray.o \
@@ -137,7 +138,8 @@ HEADERSPRIV =	\
 		raster-private.h \
 		snmp-private.h \
 		string-private.h \
-		thread-private.h
+		thread-private.h \
+		ippusb-private.h
 
 
 #
diff --git a/cups/ippusb-private.h b/cups/ippusb-private.h
new file mode 100644
index 0000000..3eb890c
--- /dev/null
+++ b/cups/ippusb-private.h
@@ -0,0 +1,34 @@
+// Copyright 2017 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef _CUPS_IPPUSB_H_
+#define _CUPS_IPPUSB_H_
+
+// Attempts to open the socket used to communicate with ippusb_manager, and if
+// successful returns a file descriptor of the socket.
+int open_ippusb_manager_socket(void);
+
+// Sends the provided message through the stream socket referred to by |fd|.
+void send_message(int fd, const char* msg);
+
+// Attempts to receive a message from the stream socket referred to by |fd|.
+char* get_message(int fd);
+
+// Sends a query message to the ippusb_manager through the socket |fd|, and
+// returns the response from ippusb_manager.
+char* query_ippusb_manager(int fd, const char* msg);
+
+// Verifies that the response string is not null and does not contain any
+// invalid characters.
+int valid_response(const char* response);
+
+// Returns a new a new uri based on the given |uri| that replaces the scheme
+// prefix with the given |scheme|.
+char* change_scheme(const char* uri, const char* scheme);
+
+// Waits for a maximum time of |timeout| until the socket at |filename| is ready
+// to accept connections.
+void wait_for_socket(const char* filename, long timeout);
+
+#endif /* _CUPS_IPPUSB_H_ */
diff --git a/cups/ippusb.c b/cups/ippusb.c
new file mode 100644
index 0000000..380f666
--- /dev/null
+++ b/cups/ippusb.c
@@ -0,0 +1,211 @@
+// Copyright 2017 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ippusb-private.h"
+#include "language-private.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <strings.h>
+#include <time.h>
+
+#include <poll.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+int open_ippusb_manager_socket(void) {
+  int fd;
+
+  _cupsLangPrintf(stderr, _("Attempting to open socket"));
+
+  fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+  if (fd < 0) {
+    _cupsLangPrintf(stderr, _("Failed to open stream socket: %s"),
+                    strerror(errno));
+    _exit(1);
+  }
+
+  _cupsLangPrintf(stderr, _("Attempting to connect to socket"));
+
+  struct sockaddr_un addr;
+  memset(&addr, 0, sizeof(addr));
+  addr.sun_family = AF_UNIX;
+  strcpy(addr.sun_path, "/run/ippusb/ippusb_manager.sock");
+
+  if (connect(fd, &addr, sizeof(struct sockaddr_un)) != 0) {
+    close(fd);
+    _cupsLangPrintf(stderr, _("Failed to connect to socket: %s"),
+                    strerror(errno));
+    _exit(1);
+  }
+
+  return fd;
+}
+
+// Writes a message to the socket described by |fd| as a stream of bytes. The
+// first byte represents the length of the message, and the following bytes are
+// filled using |msg|.
+void send_message(int fd, const char* msg) {
+  size_t remaining = strlen(msg) + 1;
+  if (remaining > UINT8_MAX) {
+    _cupsLangPrintf(stderr, _("The message to be sent is too large"));
+    _exit(1);
+  }
+
+  // Send the length of the message.
+  uint8_t message_length = (uint8_t) remaining;
+  if (send(fd, &message_length, 1, 0) < 0) {
+    _cupsLangPrintf(stderr, _("Failed to send message length"));
+    _exit(1);
+  }
+
+  size_t total = 0;
+
+  while (remaining > 0) {
+    ssize_t sent = send(fd, msg + total, remaining, MSG_NOSIGNAL);
+
+    if (sent < 0) {
+      _cupsLangPrintf(stderr, _("Failed to send message"));
+      _exit(1);
+    }
+
+    total += sent;
+    if (sent >= remaining)
+      remaining = 0;
+    else
+      remaining -= sent;
+  }
+}
+
+char* get_message(int fd) {
+  // Poll the file descriptor first before trying to read. In the event that
+  // ippusb_manager exited unexpectedly before responding on the socket we want
+  // to be able to exit before blocking on read.
+  struct pollfd poll_fd;
+  poll_fd.fd = fd;
+  poll_fd.events = POLLIN;
+  int timeout = 1000;
+  if (poll(&poll_fd, 1, timeout) <= 0) {
+    _cupsLangPrintf(stderr, _("Failed to receive response"));
+    _exit(1);
+  }
+
+  // Get the first byte out of the stream which contains the length of the
+  // message.
+  uint8_t message_length;
+  if (recv(fd, &message_length, 1, 0) < 0) {
+    _cupsLangPrintf(stderr, _("Failed to get message length"));
+    _exit(1);
+  }
+
+  char* buf = (char*) malloc(sizeof(*buf) * message_length);
+  ssize_t gotten_size;
+  size_t total_size = 0;
+
+  while (total_size < message_length) {
+    gotten_size =
+        recv(fd, buf + total_size, message_length - total_size, 0);
+
+    if (gotten_size < 0) {
+      _cupsLangPrintf(stderr, _("Failed to receive message"));
+      _exit(1);
+    }
+
+    total_size += gotten_size;
+  }
+
+  return buf;
+}
+
+char* query_ippusb_manager(int fd, const char* msg) {
+  _cupsLangPrintf(stderr, _("Attempting to write to socket"));
+  send_message(fd, msg);
+
+  _cupsLangPrintf(stderr, _("Attempting to read response"));
+  char* response = get_message(fd);
+  _cupsLangPrintf(stderr, _("Finished reading response"));
+
+  if (!valid_response(response)) {
+    _cupsLangPrintf(stderr, _("Invalid response"));
+    _exit(1);
+  }
+
+  if (!strcasecmp(response, "device not found")) {
+    _cupsLangPrintf(stderr, _("Device not found"));
+    _exit(1);
+  }
+
+  return response;
+}
+
+int valid_response(const char* response) {
+  if (!response)
+    return 0;
+
+  const char* p = response;
+  while (*p) {
+    if (!isalpha(*p) && !isdigit(*p) && *p != '_' && *p != '.' && *p != ' ')
+      return 0;
+    ++p;
+  }
+
+  return 1;
+}
+
+char* change_scheme(const char* uri, const char* scheme) {
+  char* p = strchr(uri, ':');
+  if (!p)
+    return NULL;
+
+  char* updated_uri;
+  if (asprintf(&updated_uri, "%s%s", scheme, p) == -1)
+    return NULL;
+
+  return updated_uri;
+}
+
+void wait_for_socket(const char* filename, long timeout) {
+  int fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+  if (fd < 0) {
+    _cupsLangPrintf(stderr, _("Failed to create socket"));
+    _exit(1);
+  }
+
+  struct sockaddr_un addr;
+  memset(&addr, 0, sizeof(addr));
+  addr.sun_family = AF_UNIX;
+  strcpy(addr.sun_path, filename);
+
+  _cupsLangPrintf(stderr, _("Waiting for %s to be ready for connections"),
+                  filename);
+
+  struct timespec start;
+  if (clock_gettime(CLOCK_MONOTONIC, &start) < 0) {
+    _cupsLangPrintf(stderr, _("Failed to get clock time"));
+    _exit(1);
+  }
+
+  while (connect(fd, (struct sockaddr*) &addr, sizeof(addr)) < 0) {
+    struct timespec current;
+    if (clock_gettime(CLOCK_MONOTONIC, &current) < 0) {
+      _cupsLangPrintf(stderr, _("Failed to get clock time"));
+      _exit(1);
+    }
+
+    if (current.tv_sec - start.tv_sec >= timeout) {
+      _cupsLangPrintf(stderr, _("Timed out waiting for socket %s"), filename);
+      _exit(1);
+    }
+    usleep(100);
+  }
+
+  _cupsLangPrintf(stderr, _("%s is now ready for connections"), filename);
+
+  close(fd);
+}
diff --git a/systemv/lpadmin.c b/systemv/lpadmin.c
index c181d2b..f0f9e33 100644
--- a/systemv/lpadmin.c
+++ b/systemv/lpadmin.c
@@ -20,6 +20,7 @@
 #define _CUPS_NO_DEPRECATED
 #define _PPD_DEPRECATED
 #include <cups/cups-private.h>
+#include <cups/ippusb-private.h>
 
 
 /*
@@ -1217,10 +1218,35 @@ get_printer_ppd(const char *uri,	/* I - Printer URI */
     return (NULL);
   }
 
-  http = httpConnect2(host, port, NULL, AF_UNSPEC, !strcmp(scheme, "ipps") ? HTTP_ENCRYPTION_ALWAYS : HTTP_ENCRYPTION_IF_REQUESTED, 1, 30000, NULL);
-  if (!http)
-  {
-    _cupsLangPrintf(stderr, _("%s: Unable to connect to \"%s:%d\": %s"), "lpadmin", host, port, cupsLastErrorString());
+  // If the scheme is ippusb then a query is sent to the ippusb_manager service
+  // to check if the printer is currently connected and get the name of the
+  // socket used for communication with the printer.
+  if (!strcmp(scheme, "ippusb")) {
+    int sock = open_ippusb_manager_socket();
+    char* response = query_ippusb_manager(sock, host);
+    _cupsLangPrintf(stderr, _("lpadmin: received response \"%s\""), response);
+
+    close(sock);
+
+    int ret = snprintf(host, sizeof(host), "/run/ippusb/%s", response);
+    if (ret < 0 || ret >= sizeof(host)) {
+      _cupsLangPrintf(stderr, _("lpadmin: Failed to overwrite host"));
+      _exit(1);
+    }
+
+    free(response);
+
+    // Wait a maximum of 3 seconds for the socket to be created.
+    wait_for_socket(host, 3);
+  }
+
+  http = httpConnect2(host, port, NULL, AF_UNSPEC,
+                      !strcmp(scheme, "ipps") ? HTTP_ENCRYPTION_ALWAYS
+                                              : HTTP_ENCRYPTION_IF_REQUESTED,
+                      1, 30000, NULL);
+  if (!http) {
+    _cupsLangPrintf(stderr, _("%s: Unable to connect to \"%s:%d\": %s"),
+                    "lpadmin", host, port, cupsLastErrorString());
     return (NULL);
   }
 
@@ -1229,7 +1255,26 @@ get_printer_ppd(const char *uri,	/* I - Printer URI */
   */
 
   request = ippNewRequest(IPP_OP_GET_PRINTER_ATTRIBUTES);
-  ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri", NULL, uri);
+  if (!strcmp(scheme, "ippusb")) {
+    // Change the uri back to use the ipp scheme for communicating with the cups
+    // server and so that communications will be understood by the printer.
+    // We can't simply change the existing uri because we want lpadmin to save
+    // the printer in the system as "ippusb", but need the "ipp" scheme in
+    // |fixed_uri| in order to communicate with the printer.
+    char* fixed_uri = change_scheme(uri, "ipp");
+    if (!fixed_uri) {
+      _cupsLangPrintf(stderr, _("%s: Failed to change uri to %s"), "lpadmin",
+                      "ipp");
+      _exit(1);
+    }
+    ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri", NULL,
+                 fixed_uri);
+    free(fixed_uri);
+  } else {
+    ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri", NULL,
+                 uri);
+  }
+
   response = cupsDoRequest(http, request, resource);
 
   if (!_ppdCreateFromIPP(buffer, bufsize, response))
@@ -1357,6 +1402,8 @@ set_printer_options(
   else
     request = ippNewRequest(IPP_OP_CUPS_ADD_MODIFY_PRINTER);
 
+  _cupsLangPrintf(stderr, _("lpadmin: printer uri %s"), uri);
+
   ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri", NULL, uri);
   ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_NAME, "requesting-user-name", NULL, cupsUser());
 
-- 
2.16.0.rc0.223.g4a4ac83678-goog