Simple engine using HAL, XML parser, test application.

pam_usb/src/Makefile

@@ -0,0 +1,17 @@
+SRC	= test.c \
+	  conf.c \
+	  log.c \
+	  xpath.c \
+	  hal.c
+OBJ	= $(SRC:.c=.o)
+NAME	= test
+CC	= gcc
+CFLAGS	= -Wall `pkg-config --cflags hal` `pkg-config --cflags libxml-2.0` 
+LDFLAGS	= `pkg-config --libs hal` `pkg-config --libs libxml-2.0`
+
+all	: $(NAME)
+$(NAME)	: $(OBJ)
+	$(CC) -o $(NAME) $(LDFLAGS) $(OBJ)
+
+clean	:
+	rm -f $(OBJ)

pam_usb/src/conf.c

@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include "conf.h"
+#include "xpath.h"
+#include "log.h"
+
+static void	pusb_conf_options_get_from(t_pusb_options *opts,
+					   const char *from,
+					   xmlDoc *doc)
+{
+  pusb_xpath_get_string_from(doc, from, "option[@name='hostname']",
+			     opts->hostname, sizeof(opts->hostname));
+  pusb_xpath_get_bool_from(doc, from, "option[@name='debug']",
+			   &(opts->debug));
+  pusb_xpath_get_bool_from(doc, from, "option[@name='enable']",
+			   &(opts->enable));
+  pusb_xpath_get_bool_from(doc, from, "option[@name='try_otp']",
+			   &(opts->try_otp));
+  pusb_xpath_get_bool_from(doc, from, "option[@name='enforce_otp']",
+			   &(opts->enforce_otp));
+}
+
+static int		pusb_conf_parse_options(t_pusb_options *opts,
+						xmlDoc *doc,
+						const char *user,
+						const char *service)
+{
+  char			*xpath = NULL;
+  size_t		xpath_size;
+  int			i;
+  struct s_opt_list	opt_list[] = {
+    { CONF_DEVICE_XPATH, opts->device.name },
+    { CONF_USER_XPATH, (char *)user },
+    { CONF_SERVICE_XPATH, (char *)service },
+    { NULL, NULL }
+  };
+
+  pusb_conf_options_get_from(opts, "//configuration/defaults/", doc);
+  for (i = 0; opt_list[i].name != NULL; ++i)
+    {
+      xpath_size = strlen(opt_list[i].name) + strlen(opt_list[i].value) + 1;
+      if (!(xpath = malloc(xpath_size)))
+	{
+	  log_error("malloc error\n");
+	  return (0);
+	}
+      memset(xpath, 0x00, xpath_size);
+      snprintf(xpath, xpath_size, opt_list[i].name, opt_list[i].value, "");
+      pusb_conf_options_get_from(opts, xpath, doc);
+      free(xpath);
+    }
+  return (1);
+}
+
+static int	pusb_conf_device_get_property(t_pusb_options *opts,
+					      xmlDoc *doc,
+					      const char *property,
+					      char *store,
+					      size_t size)
+{
+  char		*xpath = NULL;
+  size_t	xpath_len;
+  int		retval;
+
+  xpath_len = strlen(CONF_DEVICE_XPATH) + strlen(opts->device.name) + \
+    strlen(property) + 1;
+  if (!(xpath = malloc(xpath_len)))
+    {
+      log_error("malloc error!\n");
+      return (0);
+    }
+  memset(xpath, 0x00, xpath_len);
+  snprintf(xpath, xpath_len, CONF_DEVICE_XPATH, opts->device.name,
+	   property);
+  retval = pusb_xpath_get_string(doc, xpath, store, size);
+  free(xpath);
+  return (retval);
+}
+
+static int	pusb_conf_parse_device(t_pusb_options *opts, xmlDoc *doc)
+{
+  log_debug("Parsing settings...\n");
+  if (!pusb_conf_device_get_property(opts, doc, "vendor", opts->device.vendor,
+				      sizeof(opts->device.vendor)))
+    return (0);
+  if (!pusb_conf_device_get_property(opts, doc, "model", opts->device.model,
+				     sizeof(opts->device.model)))
+    return (0);
+  if (!pusb_conf_device_get_property(opts, doc, "serial", opts->device.serial,
+				     sizeof(opts->device.serial)))
+    return (0);
+  return (1);
+}
+
+int	pusb_conf_init(t_pusb_options *opts)
+{
+  memset(opts, 0x00, sizeof(*opts));
+  if (gethostname(opts->hostname, sizeof(opts->hostname)) == -1)
+    {
+      log_error("gethostname: %s\n", strerror(errno));
+      return (0);
+    }
+  opts->enable = 1;
+  opts->try_otp = 1;
+  opts->enforce_otp = 0;
+  opts->debug = 0;
+  return (1);
+}
+
+int		pusb_conf_parse(const char *file, t_pusb_options *opts,
+				const char *user, const char *service)
+{
+  xmlDoc	*doc = NULL;
+  int		retval;
+  char		device_xpath[sizeof(CONF_USER_XPATH) + CONF_USER_MAXLEN + \
+			     sizeof("device")];
+
+  if (strlen(user) > CONF_USER_MAXLEN)
+    {
+      log_error("Username \"%s\" is too long (max: %d)\n", user,
+		CONF_USER_MAXLEN);
+      return (0);
+    }
+  if (!(doc = xmlReadFile(file, NULL, 0)))
+    {
+      log_error("Unable to parse \"%s\"\n", file);
+      return (0);
+    }
+  snprintf(device_xpath, sizeof(device_xpath), CONF_USER_XPATH, user,
+	   "device");
+  retval = pusb_xpath_get_string(doc,
+				 device_xpath,
+				 opts->device.name,
+				 sizeof(opts->device.name));
+  if (!retval || !pusb_conf_parse_device(opts, doc))
+    {
+      log_error("No device found for user \"%s\"\n", user);
+      xmlFreeDoc(doc);
+      xmlCleanupParser();
+      return (0);
+    }
+  if (!pusb_conf_parse_options(opts, doc, user, service))
+    {
+      xmlFreeDoc(doc);
+      xmlCleanupParser();
+      return (0);
+    }
+  xmlFreeDoc(doc);
+  xmlCleanupParser();
+  return (1);
+}

pam_usb/src/conf.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef PUSB_CONF_H_
+# define PUSB_CONF_H_
+# define CONF_DEVICE_XPATH "//configuration/devices/device[@id='%s']/%s"
+# define CONF_USER_XPATH "//configuration/users/user[@id='%s']/%s"
+# define CONF_SERVICE_XPATH "//configuration/services/service[@id='%s']/%s"
+# define CONF_USER_MAXLEN 32
+
+typedef struct	pusb_device
+{
+  char		name[32];
+  char		vendor[32];
+  char		model[32];
+  char		serial[64];
+}		t_pusb_device;
+
+typedef struct	pusb_options
+{
+  int		enable;
+  int		try_otp;
+  int		enforce_otp;
+  int		debug;
+  char		hostname[32];
+  t_pusb_device	device;
+}		t_pusb_options;
+
+struct	s_opt_list
+{
+  char	*name;
+  char	*value;
+};
+
+int	pusb_conf_init(t_pusb_options *opts);
+int	pusb_conf_parse(const char *file, t_pusb_options *opts,
+			const char *user, const char *service);
+
+#endif /* !PUSB_CONF_H_ */

pam_usb/src/conf.xml

@@ -0,0 +1,42 @@
+<configuration>
+	<defaults>
+		<option name="hostname">foobar</option>
+		<option name="debug">true</option>
+		<option name="try_otp">true</option>
+		<option name="enforce_otp">false</option>
+	</defaults>
+
+	<devices>
+		<device id="foobar">
+			<vendor>SanDisk Corp.</vendor>
+			<model>Cruzer Titanium</model>
+			<serial>SNDKB882652FC4A03701</serial>
+		</device>
+	</devices>
+
+	<users>
+		<user id="scox">
+			<device>foobar</device>
+		</user>
+
+		<user id="root">
+			<device>foobar</device>
+			<option name="enforce_otp">true</option>
+		</user>
+	</users>
+
+	<services>
+		<!-- Disable pam_usb for sshd (nonsense) -->
+		<service id="ssh">
+			<option name="enable">false</option>
+		</service>
+
+		<!-- Speed up 'login' authentication by disabling one time pads.
+		     This setting will not affect user 'root' as he/she is
+		     enforcing one time pads (enforce_otp).
+		-->
+		<service id="login">
+			<option name="try_otp">false</option>
+		</service>
+	</services>
+</configuration>

pam_usb/src/hal.c

@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <string.h>
+#include <dbus/dbus.h>
+#include <libhal.h>
+#include "conf.h"
+#include "log.h"
+
+static DBusConnection	*pusb_hal_dbus_connect(void)
+{
+  DBusConnection	*dbus = NULL;
+  DBusError		error;
+
+  dbus_error_init(&error);
+  if (!(dbus = dbus_bus_get(DBUS_BUS_SYSTEM, &error)))
+    {
+      log_error("Cannot connect to system bus: %s\n",
+		error.message);
+      dbus_error_free(&error);
+      return (NULL);
+    }
+  return (dbus);
+}
+
+static void	pusb_hal_dbus_disconnect(DBusConnection *dbus)
+{
+  dbus_connection_close(dbus);
+  dbus_connection_unref(dbus);
+  dbus_shutdown();
+}
+
+static LibHalContext	*pusb_hal_init(DBusConnection *dbus)
+{
+  DBusError		error;
+  LibHalContext		*ctx = NULL;
+
+  dbus_error_init(&error);
+  if (!(ctx = libhal_ctx_new()))
+    {
+      log_error("Failed to create a HAL context\n");
+      return (NULL);
+    }
+  if (!libhal_ctx_set_dbus_connection(ctx, dbus))
+    {
+      log_error("Failed to attach dbus connection to hal\n");
+      libhal_ctx_free(ctx);
+      return (NULL);
+    }
+  if (!libhal_ctx_init(ctx, &error))
+    {
+      log_error("libhal_ctx_init: %s\n", error.name, error.message);
+      libhal_ctx_free(ctx);
+      return (NULL);
+    }
+  return (ctx);
+}
+
+static int		pusb_hal_verify_model(LibHalContext *ctx,
+						     t_pusb_options *opts,
+						     const char *udi)
+{
+  DBusError		error;
+  char			*data;
+  int			i;
+  struct s_opt_list	check_list[] = {
+    { "usb_device.vendor", opts->device.vendor },
+    { "info.product", opts->device.model },
+    { NULL, NULL }
+  };
+
+  log_debug("Verifying model...\n");
+  dbus_error_init(&error);
+  for (i = 0; check_list[i].name; ++i)
+    {
+      data = libhal_device_get_property_string(ctx, udi,
+					       check_list[i].name,
+					       &error);
+      if (!data)
+	{
+	  log_error("Cannot retrieve device %s: %s\n",
+		    check_list[i].name,
+		    error.message);
+	  dbus_error_free(&error);
+	  return (0);
+	}
+      if (strcmp(data, check_list[i].value) != 0)
+	{
+	  log_error("[KO]\t%s -> %s\n", check_list[i].name, data);
+	  libhal_free_string(data);
+	  return (0);
+	}
+      log_debug("[OK]\t%s -> %s \n", check_list[i].name, data);
+      libhal_free_string(data);
+    }
+  return (1);
+}
+
+static int	pusb_hal_find_device(LibHalContext *ctx,
+				     t_pusb_options *opts)
+{
+  DBusError	error;
+  char		**devices;
+  int		n_devices;
+  int		retval = 0;
+
+  dbus_error_init(&error);
+  if (!(devices = libhal_manager_find_device_string_match(ctx,
+							  "usb_device.serial",
+							  opts->device.serial,
+							  &n_devices,
+							  &error)))
+    {
+      log_error("Unable to find device \"%s\": %s\n", opts->device.name,
+		error.message);
+      dbus_error_free(&error);
+      return (0);
+    }
+  if (n_devices > 0)
+    {
+      log_debug("Device \"%s\" connected (S/N: %s)\n", opts->device.name,
+		opts->device.serial);
+      retval = pusb_hal_verify_model(ctx, opts, devices[0]);
+    }
+  else
+    log_error("Device \"%s\" not connected\n", opts->device.name);
+  libhal_free_string_array(devices);
+  return (retval);
+}
+
+int		pusb_hal_device_check(t_pusb_options *opts)
+{
+  DBusConnection	*dbus;
+  LibHalContext		*ctx;
+  int			retval;
+
+  if (!(dbus = pusb_hal_dbus_connect()))
+    return (0);
+  if (!(ctx = pusb_hal_init(dbus)))
+    return (0);
+  retval = pusb_hal_find_device(ctx, opts);
+  pusb_hal_dbus_disconnect(dbus);
+  libhal_ctx_free(ctx);
+  return (retval);
+}

pam_usb/src/hal.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef HAL_H_
+# define HAL_H_
+
+int	pusb_hal_device_check(t_pusb_options *opts);
+
+#endif /* !HAL_H_ */

pam_usb/src/log.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include "log.h"
+
+void		log_debug(const char *fmt, ...)
+{
+  va_list	ap;
+
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+}
+
+void		log_error(const char *fmt, ...)
+{
+  va_list	ap;
+
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+}
+
+void		log_verbose(const char *fmt, ...)
+{
+  va_list	ap;
+
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+}

pam_usb/src/log.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef LOG_H_
+# define LOG_H_
+
+void	log_debug(const char *fmt, ...);
+void	log_error(const char *fmt, ...);
+void	log_verbose(const char *fmt, ...);
+
+#endif /* !LOG_H_ */

pam_usb/src/test.c

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdio.h>
+#include "conf.h"
+#include "hal.h"
+#include "log.h"
+
+static void	pusb_dump_conf(t_pusb_options *opts)
+{
+  printf("\nConfiguration dump:\n");
+  printf("enable:\t\t%d\n", opts->enable);
+  printf("try_otp:\t%d\n", opts->try_otp);
+  printf("enforce_otp:\t%d\n", opts->enforce_otp);
+  printf("debug:\t\t%d\n", opts->debug);
+  printf("hostname:\t%s\n", opts->hostname);
+}
+
+int	main(int argc, char **argv)
+{
+  t_pusb_options	opts;
+
+  if (argc < 3)
+    {
+      printf("Usage: %s <username> <service>\n", argv[0]);
+      return (1);
+    }
+  pusb_conf_init(&opts);
+  if (!pusb_conf_parse("conf.xml", &opts, argv[1], argv[2]))
+    return (0);
+  pusb_dump_conf(&opts);
+  if (!opts.enable)
+    {
+      printf("not enabled, exiting\n");
+      return (0);
+    }
+  printf("\n");
+  printf ("Access %s.\n", pusb_hal_device_check(&opts) ? "granted" : "denied");
+  return (0);
+}

pam_usb/src/xpath.c

@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <libxml/xpath.h>
+#include <string.h>
+#include "xpath.h"
+#include "log.h"
+
+static xmlXPathObject	*pusb_xpath_match(xmlDocPtr doc, const char *path)
+{
+  xmlXPathContext	*context = NULL;
+  xmlXPathObject	*result = NULL;
+
+  context = xmlXPathNewContext(doc);
+  if (context == NULL)
+    {
+      log_error("Unable to create XML context\n");
+      return (NULL);
+    }
+  result = xmlXPathEvalExpression((xmlChar *)path, context);
+  xmlXPathFreeContext(context);
+  if (result == NULL)
+    {
+      log_error("Error in xmlXPathEvalExpression\n");
+      return (NULL);
+    }
+  if (xmlXPathNodeSetIsEmpty(result->nodesetval))
+    {
+      xmlXPathFreeObject(result);
+      return (NULL);
+    }
+  return (result);
+}
+
+int			pusb_xpath_get_string(xmlDocPtr doc, const char *path,
+					      char *value, size_t size)
+{
+  xmlXPathObject	*result = NULL;
+  xmlNode		*node = NULL;
+  xmlChar		*result_string = NULL;
+
+  if (!(result = pusb_xpath_match(doc, path)))
+    return (0);
+
+  if (result->nodesetval->nodeNr > 1)
+    {
+      xmlXPathFreeObject(result);
+      log_debug("Syntax error: %s: more than one record found\n", path);
+      return (0);
+    }
+
+  node = result->nodesetval->nodeTab[0]->xmlChildrenNode;
+  result_string = xmlNodeListGetString(doc, node, 1);
+  if (strlen((const char *)result_string) + 1 > size)
+    {
+      xmlFree(result_string);
+      xmlXPathFreeObject(result);
+      log_debug("Result for %s (%s) is too long (max: %d)\n",
+		path, (const char *)result_string, size);
+      return (0);
+    }
+  memset(value, '\0', size);
+  strncpy(value, (const char *)result_string, size);
+  xmlFree(result_string);
+  xmlXPathFreeObject(result);
+  return (1);
+}
+
+int			pusb_xpath_get_string_from(xmlDocPtr doc,
+						   const char *base,
+						   const char *path,
+						   char *value, size_t size)
+{
+  char			*xpath = NULL;
+  size_t		xpath_size;
+  int			retval;
+
+  xpath_size = strlen(base) + strlen(path) + 1;
+  if (!(xpath = malloc(xpath_size)))
+    {
+      log_error("malloc error !\n");
+      return (0);
+    }
+  memset(xpath, 0x00, xpath_size);
+  snprintf(xpath, xpath_size, "%s%s", base, path);
+  retval = pusb_xpath_get_string(doc, xpath, value, size);
+  if (retval)
+    log_debug("%s%s -> %s\n", base, path, value);
+  free(xpath);
+  return (retval);
+}
+
+int	pusb_xpath_get_bool(xmlDocPtr doc, const char *path, int *value)
+{
+  char	ret[6]; /* strlen("false") + 1 */
+
+  if (!pusb_xpath_get_string(doc, path, ret, sizeof(ret)))
+    return (0);
+
+  if (!strcmp(ret, "true"))
+    {
+      *value = 1;
+      return (1);
+    }
+
+  if (!strcmp(ret, "false"))
+    {
+      *value = 0;
+      return (1);
+    }
+
+  log_debug("Expecting a boolean, got %s\n", ret);
+  return (0);
+}
+
+int			pusb_xpath_get_bool_from(xmlDocPtr doc,
+						 const char *base,
+						 const char *path,
+						 int *value)
+{
+  char		*xpath = NULL;
+  size_t	xpath_size;
+  int		retval;
+
+  xpath_size = strlen(base) + strlen(path) + 1;
+  if (!(xpath = malloc(xpath_size)))
+    {
+      log_error("malloc error!\n");
+      return (0);
+    }
+  memset(xpath, 0x00, xpath_size);
+  snprintf(xpath, xpath_size, "%s%s", base, path);
+  retval = pusb_xpath_get_bool(doc, xpath, value);
+  free(xpath);
+  if (retval)
+    log_debug("%s%s -> %s\n", base, path, *value ? "true" : "false");
+  return (retval);
+}

pam_usb/src/xpath.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2003-2006 Andrea Luzzardi <scox@sig11.org>
+ *
+ * This file is part of the pam_usb project. pam_usb is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef PUSB_XPATH_H_
+# define PUSB_XPATH_H_
+# include <libxml/parser.h>
+
+int pusb_xpath_get_string(xmlDocPtr doc, const char *path, char *value,
+			  size_t size);
+int pusb_xpath_get_bool(xmlDocPtr doc, const char *path, int *value);
+int pusb_xpath_get_string_from(xmlDocPtr doc, const char *base,
+			       const char *path, char *value, size_t size);
+int pusb_xpath_get_bool_from(xmlDocPtr doc, const char *base, const char *path,
+			     int *value);
+#endif /* !PUSB_XPATH_H_ */