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accesslib.php
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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* This file contains functions for managing user access
*
* <b>Public API vs internals</b>
*
* General users probably only care about
*
* Context handling
* - context_course::instance($courseid), context_module::instance($cm->id), context_coursecat::instance($catid)
* - context::instance_by_id($contextid)
* - $context->get_parent_contexts();
* - $context->get_child_contexts();
*
* Whether the user can do something...
* - has_capability()
* - has_any_capability()
* - has_all_capabilities()
* - require_capability()
* - require_login() (from moodlelib)
* - is_enrolled()
* - is_viewing()
* - is_guest()
* - is_siteadmin()
* - isguestuser()
* - isloggedin()
*
* What courses has this user access to?
* - get_enrolled_users()
*
* What users can do X in this context?
* - get_enrolled_users() - at and bellow course context
* - get_users_by_capability() - above course context
*
* Modify roles
* - role_assign()
* - role_unassign()
* - role_unassign_all()
*
* Advanced - for internal use only
* - load_all_capabilities()
* - reload_all_capabilities()
* - has_capability_in_accessdata()
* - get_user_access_sitewide()
* - load_course_context()
* - load_role_access_by_context()
* - etc.
*
* <b>Name conventions</b>
*
* "ctx" means context
*
* <b>accessdata</b>
*
* Access control data is held in the "accessdata" array
* which - for the logged-in user, will be in $USER->access
*
* For other users can be generated and passed around (but may also be cached
* against userid in $ACCESSLIB_PRIVATE->accessdatabyuser).
*
* $accessdata is a multidimensional array, holding
* role assignments (RAs), role-capabilities-perm sets
* (role defs) and a list of courses we have loaded
* data for.
*
* Things are keyed on "contextpaths" (the path field of
* the context table) for fast walking up/down the tree.
* <code>
* $accessdata['ra'][$contextpath] = array($roleid=>$roleid)
* [$contextpath] = array($roleid=>$roleid)
* [$contextpath] = array($roleid=>$roleid)
* </code>
*
* Role definitions are stored like this
* (no cap merge is done - so it's compact)
*
* <code>
* $accessdata['rdef']["$contextpath:$roleid"]['mod/forum:viewpost'] = 1
* ['mod/forum:editallpost'] = -1
* ['mod/forum:startdiscussion'] = -1000
* </code>
*
* See how has_capability_in_accessdata() walks up the tree.
*
* First we only load rdef and ra down to the course level, but not below.
* This keeps accessdata small and compact. Below-the-course ra/rdef
* are loaded as needed. We keep track of which courses we have loaded ra/rdef in
* <code>
* $accessdata['loaded'] = array($courseid1=>1, $courseid2=>1)
* </code>
*
* <b>Stale accessdata</b>
*
* For the logged-in user, accessdata is long-lived.
*
* On each pageload we load $ACCESSLIB_PRIVATE->dirtycontexts which lists
* context paths affected by changes. Any check at-or-below
* a dirty context will trigger a transparent reload of accessdata.
*
* Changes at the system level will force the reload for everyone.
*
* <b>Default role caps</b>
* The default role assignment is not in the DB, so we
* add it manually to accessdata.
*
* This means that functions that work directly off the
* DB need to ensure that the default role caps
* are dealt with appropriately.
*
* @package core_access
* @copyright 1999 onwards Martin Dougiamas http://dougiamas.com
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/** No capability change */
define('CAP_INHERIT', 0);
/** Allow permission, overrides CAP_PREVENT defined in parent contexts */
define('CAP_ALLOW', 1);
/** Prevent permission, overrides CAP_ALLOW defined in parent contexts */
define('CAP_PREVENT', -1);
/** Prohibit permission, overrides everything in current and child contexts */
define('CAP_PROHIBIT', -1000);
/** System context level - only one instance in every system */
define('CONTEXT_SYSTEM', 10);
/** User context level - one instance for each user describing what others can do to user */
define('CONTEXT_USER', 30);
/** Course category context level - one instance for each category */
define('CONTEXT_COURSECAT', 40);
/** Course context level - one instances for each course */
define('CONTEXT_COURSE', 50);
/** Course module context level - one instance for each course module */
define('CONTEXT_MODULE', 70);
/**
* Block context level - one instance for each block, sticky blocks are tricky
* because ppl think they should be able to override them at lower contexts.
* Any other context level instance can be parent of block context.
*/
define('CONTEXT_BLOCK', 80);
/** Capability allow management of trusts - NOT IMPLEMENTED YET - see {@link http://docs.moodle.org/dev/Hardening_new_Roles_system} */
define('RISK_MANAGETRUST', 0x0001);
/** Capability allows changes in system configuration - see {@link http://docs.moodle.org/dev/Hardening_new_Roles_system} */
define('RISK_CONFIG', 0x0002);
/** Capability allows user to add scripted content - see {@link http://docs.moodle.org/dev/Hardening_new_Roles_system} */
define('RISK_XSS', 0x0004);
/** Capability allows access to personal user information - see {@link http://docs.moodle.org/dev/Hardening_new_Roles_system} */
define('RISK_PERSONAL', 0x0008);
/** Capability allows users to add content others may see - see {@link http://docs.moodle.org/dev/Hardening_new_Roles_system} */
define('RISK_SPAM', 0x0010);
/** capability allows mass delete of data belonging to other users - see {@link http://docs.moodle.org/dev/Hardening_new_Roles_system} */
define('RISK_DATALOSS', 0x0020);
/** rolename displays - the name as defined in the role definition, localised if name empty */
define('ROLENAME_ORIGINAL', 0);
/** rolename displays - the name as defined by a role alias at the course level, falls back to ROLENAME_ORIGINAL if alias not present */
define('ROLENAME_ALIAS', 1);
/** rolename displays - Both, like this: Role alias (Original) */
define('ROLENAME_BOTH', 2);
/** rolename displays - the name as defined in the role definition and the shortname in brackets */
define('ROLENAME_ORIGINALANDSHORT', 3);
/** rolename displays - the name as defined by a role alias, in raw form suitable for editing */
define('ROLENAME_ALIAS_RAW', 4);
/** rolename displays - the name is simply short role name */
define('ROLENAME_SHORT', 5);
if (!defined('CONTEXT_CACHE_MAX_SIZE')) {
/** maximum size of context cache - it is possible to tweak this config.php or in any script before inclusion of context.php */
define('CONTEXT_CACHE_MAX_SIZE', 2500);
}
/**
* Although this looks like a global variable, it isn't really.
*
* It is just a private implementation detail to accesslib that MUST NOT be used elsewhere.
* It is used to cache various bits of data between function calls for performance reasons.
* Sadly, a PHP global variable is the only way to implement this, without rewriting everything
* as methods of a class, instead of functions.
*
* @access private
* @global stdClass $ACCESSLIB_PRIVATE
* @name $ACCESSLIB_PRIVATE
*/
global $ACCESSLIB_PRIVATE;
$ACCESSLIB_PRIVATE = new stdClass();
$ACCESSLIB_PRIVATE->dirtycontexts = null; // Dirty contexts cache, loaded from DB once per page
$ACCESSLIB_PRIVATE->accessdatabyuser = array(); // Holds the cache of $accessdata structure for users (including $USER)
$ACCESSLIB_PRIVATE->rolepermissions = array(); // role permissions cache - helps a lot with mem usage
$ACCESSLIB_PRIVATE->capabilities = null; // detailed information about the capabilities
/**
* Clears accesslib's private caches. ONLY BE USED BY UNIT TESTS
*
* This method should ONLY BE USED BY UNIT TESTS. It clears all of
* accesslib's private caches. You need to do this before setting up test data,
* and also at the end of the tests.
*
* @access private
* @return void
*/
function accesslib_clear_all_caches_for_unit_testing() {
global $USER;
if (!PHPUNIT_TEST) {
throw new coding_exception('You must not call clear_all_caches outside of unit tests.');
}
accesslib_clear_all_caches(true);
unset($USER->access);
}
/**
* Clears accesslib's private caches. ONLY BE USED FROM THIS LIBRARY FILE!
*
* This reset does not touch global $USER.
*
* @access private
* @param bool $resetcontexts
* @return void
*/
function accesslib_clear_all_caches($resetcontexts) {
global $ACCESSLIB_PRIVATE;
$ACCESSLIB_PRIVATE->dirtycontexts = null;
$ACCESSLIB_PRIVATE->accessdatabyuser = array();
$ACCESSLIB_PRIVATE->rolepermissions = array();
$ACCESSLIB_PRIVATE->capabilities = null;
if ($resetcontexts) {
context_helper::reset_caches();
}
}
/**
* Gets the accessdata for role "sitewide" (system down to course)
*
* @access private
* @param int $roleid
* @return array
*/
function get_role_access($roleid) {
global $DB, $ACCESSLIB_PRIVATE;
/* Get it in 1 DB query...
* - relevant role caps at the root and down
* to the course level - but not below
*/
//TODO: MUC - this could be cached in shared memory to speed up first page loading, web crawlers, etc.
$accessdata = get_empty_accessdata();
$accessdata['ra']['/'.SYSCONTEXTID] = array((int)$roleid => (int)$roleid);
// Overrides for the role IN ANY CONTEXTS down to COURSE - not below -.
/*
$sql = "SELECT ctx.path,
rc.capability, rc.permission
FROM {context} ctx
JOIN {role_capabilities} rc ON rc.contextid = ctx.id
LEFT JOIN {context} cctx
ON (cctx.contextlevel = ".CONTEXT_COURSE." AND ctx.path LIKE ".$DB->sql_concat('cctx.path',"'/%'").")
WHERE rc.roleid = ? AND cctx.id IS NULL";
$params = array($roleid);
*/
// Note: the commented out query is 100% accurate but slow, so let's cheat instead by hardcoding the blocks mess directly.
$sql = "SELECT COALESCE(ctx.path, bctx.path) AS path, rc.capability, rc.permission
FROM {role_capabilities} rc
LEFT JOIN {context} ctx ON (ctx.id = rc.contextid AND ctx.contextlevel <= ".CONTEXT_COURSE.")
LEFT JOIN ({context} bctx
JOIN {block_instances} bi ON (bi.id = bctx.instanceid)
JOIN {context} pctx ON (pctx.id = bi.parentcontextid AND pctx.contextlevel < ".CONTEXT_COURSE.")
) ON (bctx.id = rc.contextid AND bctx.contextlevel = ".CONTEXT_BLOCK.")
WHERE rc.roleid = :roleid AND (ctx.id IS NOT NULL OR bctx.id IS NOT NULL)";
$params = array('roleid'=>$roleid);
// we need extra caching in CLI scripts and cron
$rs = $DB->get_recordset_sql($sql, $params);
foreach ($rs as $rd) {
$k = "{$rd->path}:{$roleid}";
$accessdata['rdef'][$k][$rd->capability] = (int)$rd->permission;
}
$rs->close();
// share the role definitions
foreach ($accessdata['rdef'] as $k=>$unused) {
if (!isset($ACCESSLIB_PRIVATE->rolepermissions[$k])) {
$ACCESSLIB_PRIVATE->rolepermissions[$k] = $accessdata['rdef'][$k];
}
$accessdata['rdef_count']++;
$accessdata['rdef'][$k] =& $ACCESSLIB_PRIVATE->rolepermissions[$k];
}
return $accessdata;
}
/**
* Get the default guest role, this is used for guest account,
* search engine spiders, etc.
*
* @return stdClass role record
*/
function get_guest_role() {
global $CFG, $DB;
if (empty($CFG->guestroleid)) {
if ($roles = $DB->get_records('role', array('archetype'=>'guest'))) {
$guestrole = array_shift($roles); // Pick the first one
set_config('guestroleid', $guestrole->id);
return $guestrole;
} else {
debugging('Can not find any guest role!');
return false;
}
} else {
if ($guestrole = $DB->get_record('role', array('id'=>$CFG->guestroleid))) {
return $guestrole;
} else {
// somebody is messing with guest roles, remove incorrect setting and try to find a new one
set_config('guestroleid', '');
return get_guest_role();
}
}
}
/**
* Check whether a user has a particular capability in a given context.
*
* For example:
* $context = context_module::instance($cm->id);
* has_capability('mod/forum:replypost', $context)
*
* By default checks the capabilities of the current user, but you can pass a
* different userid. By default will return true for admin users, but you can override that with the fourth argument.
*
* Guest and not-logged-in users can never get any dangerous capability - that is any write capability
* or capabilities with XSS, config or data loss risks.
*
* @category access
*
* @param string $capability the name of the capability to check. For example mod/forum:view
* @param context $context the context to check the capability in. You normally get this with instance method of a context class.
* @param integer|stdClass $user A user id or object. By default (null) checks the permissions of the current user.
* @param boolean $doanything If false, ignores effect of admin role assignment
* @return boolean true if the user has this capability. Otherwise false.
*/
function has_capability($capability, context $context, $user = null, $doanything = true) {
global $USER, $CFG, $SCRIPT, $ACCESSLIB_PRIVATE;
if (during_initial_install()) {
if ($SCRIPT === "/$CFG->admin/index.php" or $SCRIPT === "/$CFG->admin/cli/install.php" or $SCRIPT === "/$CFG->admin/cli/install_database.php") {
// we are in an installer - roles can not work yet
return true;
} else {
return false;
}
}
if (strpos($capability, 'moodle/legacy:') === 0) {
throw new coding_exception('Legacy capabilities can not be used any more!');
}
if (!is_bool($doanything)) {
throw new coding_exception('Capability parameter "doanything" is wierd, only true or false is allowed. This has to be fixed in code.');
}
// capability must exist
if (!$capinfo = get_capability_info($capability)) {
debugging('Capability "'.$capability.'" was not found! This has to be fixed in code.');
return false;
}
if (!isset($USER->id)) {
// should never happen
$USER->id = 0;
debugging('Capability check being performed on a user with no ID.', DEBUG_DEVELOPER);
}
// make sure there is a real user specified
if ($user === null) {
$userid = $USER->id;
} else {
$userid = is_object($user) ? $user->id : $user;
}
// make sure forcelogin cuts off not-logged-in users if enabled
if (!empty($CFG->forcelogin) and $userid == 0) {
return false;
}
// make sure the guest account and not-logged-in users never get any risky caps no matter what the actual settings are.
if (($capinfo->captype === 'write') or ($capinfo->riskbitmask & (RISK_XSS | RISK_CONFIG | RISK_DATALOSS))) {
if (isguestuser($userid) or $userid == 0) {
return false;
}
}
// somehow make sure the user is not deleted and actually exists
if ($userid != 0) {
if ($userid == $USER->id and isset($USER->deleted)) {
// this prevents one query per page, it is a bit of cheating,
// but hopefully session is terminated properly once user is deleted
if ($USER->deleted) {
return false;
}
} else {
if (!context_user::instance($userid, IGNORE_MISSING)) {
// no user context == invalid userid
return false;
}
}
}
// context path/depth must be valid
if (empty($context->path) or $context->depth == 0) {
// this should not happen often, each upgrade tries to rebuild the context paths
debugging('Context id '.$context->id.' does not have valid path, please use build_context_path()');
if (is_siteadmin($userid)) {
return true;
} else {
return false;
}
}
// Find out if user is admin - it is not possible to override the doanything in any way
// and it is not possible to switch to admin role either.
if ($doanything) {
if (is_siteadmin($userid)) {
if ($userid != $USER->id) {
return true;
}
// make sure switchrole is not used in this context
if (empty($USER->access['rsw'])) {
return true;
}
$parts = explode('/', trim($context->path, '/'));
$path = '';
$switched = false;
foreach ($parts as $part) {
$path .= '/' . $part;
if (!empty($USER->access['rsw'][$path])) {
$switched = true;
break;
}
}
if (!$switched) {
return true;
}
//ok, admin switched role in this context, let's use normal access control rules
}
}
// Careful check for staleness...
$context->reload_if_dirty();
if ($USER->id == $userid) {
if (!isset($USER->access)) {
load_all_capabilities();
}
$access =& $USER->access;
} else {
// make sure user accessdata is really loaded
get_user_accessdata($userid, true);
$access =& $ACCESSLIB_PRIVATE->accessdatabyuser[$userid];
}
// Load accessdata for below-the-course context if necessary,
// all contexts at and above all courses are already loaded
if ($context->contextlevel != CONTEXT_COURSE and $coursecontext = $context->get_course_context(false)) {
load_course_context($userid, $coursecontext, $access);
}
return has_capability_in_accessdata($capability, $context, $access);
}
/**
* Check if the user has any one of several capabilities from a list.
*
* This is just a utility method that calls has_capability in a loop. Try to put
* the capabilities that most users are likely to have first in the list for best
* performance.
*
* @category access
* @see has_capability()
*
* @param array $capabilities an array of capability names.
* @param context $context the context to check the capability in. You normally get this with instance method of a context class.
* @param integer|stdClass $user A user id or object. By default (null) checks the permissions of the current user.
* @param boolean $doanything If false, ignore effect of admin role assignment
* @return boolean true if the user has any of these capabilities. Otherwise false.
*/
function has_any_capability(array $capabilities, context $context, $user = null, $doanything = true) {
foreach ($capabilities as $capability) {
if (has_capability($capability, $context, $user, $doanything)) {
return true;
}
}
return false;
}
/**
* Check if the user has all the capabilities in a list.
*
* This is just a utility method that calls has_capability in a loop. Try to put
* the capabilities that fewest users are likely to have first in the list for best
* performance.
*
* @category access
* @see has_capability()
*
* @param array $capabilities an array of capability names.
* @param context $context the context to check the capability in. You normally get this with instance method of a context class.
* @param integer|stdClass $user A user id or object. By default (null) checks the permissions of the current user.
* @param boolean $doanything If false, ignore effect of admin role assignment
* @return boolean true if the user has all of these capabilities. Otherwise false.
*/
function has_all_capabilities(array $capabilities, context $context, $user = null, $doanything = true) {
foreach ($capabilities as $capability) {
if (!has_capability($capability, $context, $user, $doanything)) {
return false;
}
}
return true;
}
/**
* Is course creator going to have capability in a new course?
*
* This is intended to be used in enrolment plugins before or during course creation,
* do not use after the course is fully created.
*
* @category access
*
* @param string $capability the name of the capability to check.
* @param context $context course or category context where is course going to be created
* @param integer|stdClass $user A user id or object. By default (null) checks the permissions of the current user.
* @return boolean true if the user will have this capability.
*
* @throws coding_exception if different type of context submitted
*/
function guess_if_creator_will_have_course_capability($capability, context $context, $user = null) {
global $CFG;
if ($context->contextlevel != CONTEXT_COURSE and $context->contextlevel != CONTEXT_COURSECAT) {
throw new coding_exception('Only course or course category context expected');
}
if (has_capability($capability, $context, $user)) {
// User already has the capability, it could be only removed if CAP_PROHIBIT
// was involved here, but we ignore that.
return true;
}
if (!has_capability('moodle/course:create', $context, $user)) {
return false;
}
if (!enrol_is_enabled('manual')) {
return false;
}
if (empty($CFG->creatornewroleid)) {
return false;
}
if ($context->contextlevel == CONTEXT_COURSE) {
if (is_viewing($context, $user, 'moodle/role:assign') or is_enrolled($context, $user, 'moodle/role:assign')) {
return false;
}
} else {
if (has_capability('moodle/course:view', $context, $user) and has_capability('moodle/role:assign', $context, $user)) {
return false;
}
}
// Most likely they will be enrolled after the course creation is finished,
// does the new role have the required capability?
list($neededroles, $forbiddenroles) = get_roles_with_cap_in_context($context, $capability);
return isset($neededroles[$CFG->creatornewroleid]);
}
/**
* Check if the user is an admin at the site level.
*
* Please note that use of proper capabilities is always encouraged,
* this function is supposed to be used from core or for temporary hacks.
*
* @category access
*
* @param int|stdClass $user_or_id user id or user object
* @return bool true if user is one of the administrators, false otherwise
*/
function is_siteadmin($user_or_id = null) {
global $CFG, $USER;
if ($user_or_id === null) {
$user_or_id = $USER;
}
if (empty($user_or_id)) {
return false;
}
if (!empty($user_or_id->id)) {
$userid = $user_or_id->id;
} else {
$userid = $user_or_id;
}
// Because this script is called many times (150+ for course page) with
// the same parameters, it is worth doing minor optimisations. This static
// cache stores the value for a single userid, saving about 2ms from course
// page load time without using significant memory. As the static cache
// also includes the value it depends on, this cannot break unit tests.
static $knownid, $knownresult, $knownsiteadmins;
if ($knownid === $userid && $knownsiteadmins === $CFG->siteadmins) {
return $knownresult;
}
$knownid = $userid;
$knownsiteadmins = $CFG->siteadmins;
$siteadmins = explode(',', $CFG->siteadmins);
$knownresult = in_array($userid, $siteadmins);
return $knownresult;
}
/**
* Returns true if user has at least one role assign
* of 'coursecontact' role (is potentially listed in some course descriptions).
*
* @param int $userid
* @return bool
*/
function has_coursecontact_role($userid) {
global $DB, $CFG;
if (empty($CFG->coursecontact)) {
return false;
}
$sql = "SELECT 1
FROM {role_assignments}
WHERE userid = :userid AND roleid IN ($CFG->coursecontact)";
return $DB->record_exists_sql($sql, array('userid'=>$userid));
}
/**
* Does the user have a capability to do something?
*
* Walk the accessdata array and return true/false.
* Deals with prohibits, role switching, aggregating
* capabilities, etc.
*
* The main feature of here is being FAST and with no
* side effects.
*
* Notes:
*
* Switch Role merges with default role
* ------------------------------------
* If you are a teacher in course X, you have at least
* teacher-in-X + defaultloggedinuser-sitewide. So in the
* course you'll have techer+defaultloggedinuser.
* We try to mimic that in switchrole.
*
* Permission evaluation
* ---------------------
* Originally there was an extremely complicated way
* to determine the user access that dealt with
* "locality" or role assignments and role overrides.
* Now we simply evaluate access for each role separately
* and then verify if user has at least one role with allow
* and at the same time no role with prohibit.
*
* @access private
* @param string $capability
* @param context $context
* @param array $accessdata
* @return bool
*/
function has_capability_in_accessdata($capability, context $context, array &$accessdata) {
global $CFG;
// Build $paths as a list of current + all parent "paths" with order bottom-to-top
$path = $context->path;
$paths = array($path);
while($path = rtrim($path, '0123456789')) {
$path = rtrim($path, '/');
if ($path === '') {
break;
}
$paths[] = $path;
}
$roles = array();
$switchedrole = false;
// Find out if role switched
if (!empty($accessdata['rsw'])) {
// From the bottom up...
foreach ($paths as $path) {
if (isset($accessdata['rsw'][$path])) {
// Found a switchrole assignment - check for that role _plus_ the default user role
$roles = array($accessdata['rsw'][$path]=>null, $CFG->defaultuserroleid=>null);
$switchedrole = true;
break;
}
}
}
if (!$switchedrole) {
// get all users roles in this context and above
foreach ($paths as $path) {
if (isset($accessdata['ra'][$path])) {
foreach ($accessdata['ra'][$path] as $roleid) {
$roles[$roleid] = null;
}
}
}
}
// Now find out what access is given to each role, going bottom-->up direction
$allowed = false;
foreach ($roles as $roleid => $ignored) {
foreach ($paths as $path) {
if (isset($accessdata['rdef']["{$path}:$roleid"][$capability])) {
$perm = (int)$accessdata['rdef']["{$path}:$roleid"][$capability];
if ($perm === CAP_PROHIBIT) {
// any CAP_PROHIBIT found means no permission for the user
return false;
}
if (is_null($roles[$roleid])) {
$roles[$roleid] = $perm;
}
}
}
// CAP_ALLOW in any role means the user has a permission, we continue only to detect prohibits
$allowed = ($allowed or $roles[$roleid] === CAP_ALLOW);
}
return $allowed;
}
/**
* A convenience function that tests has_capability, and displays an error if
* the user does not have that capability.
*
* NOTE before Moodle 2.0, this function attempted to make an appropriate
* require_login call before checking the capability. This is no longer the case.
* You must call require_login (or one of its variants) if you want to check the
* user is logged in, before you call this function.
*
* @see has_capability()
*
* @param string $capability the name of the capability to check. For example mod/forum:view
* @param context $context the context to check the capability in. You normally get this with context_xxxx::instance().
* @param int $userid A user id. By default (null) checks the permissions of the current user.
* @param bool $doanything If false, ignore effect of admin role assignment
* @param string $errormessage The error string to to user. Defaults to 'nopermissions'.
* @param string $stringfile The language file to load the error string from. Defaults to 'error'.
* @return void terminates with an error if the user does not have the given capability.
*/
function require_capability($capability, context $context, $userid = null, $doanything = true,
$errormessage = 'nopermissions', $stringfile = '') {
if (!has_capability($capability, $context, $userid, $doanything)) {
throw new required_capability_exception($context, $capability, $errormessage, $stringfile);
}
}
/**
* Return a nested array showing role assignments
* all relevant role capabilities for the user at
* site/course_category/course levels
*
* We do _not_ delve deeper than courses because the number of
* overrides at the module/block levels can be HUGE.
*
* [ra] => [/path][roleid]=roleid
* [rdef] => [/path:roleid][capability]=permission
*
* @access private
* @param int $userid - the id of the user
* @return array access info array
*/
function get_user_access_sitewide($userid) {
global $CFG, $DB, $ACCESSLIB_PRIVATE;
/* Get in a few cheap DB queries...
* - role assignments
* - relevant role caps
* - above and within this user's RAs
* - below this user's RAs - limited to course level
*/
// raparents collects paths & roles we need to walk up the parenthood to build the minimal rdef
$raparents = array();
$accessdata = get_empty_accessdata();
// start with the default role
if (!empty($CFG->defaultuserroleid)) {
$syscontext = context_system::instance();
$accessdata['ra'][$syscontext->path][(int)$CFG->defaultuserroleid] = (int)$CFG->defaultuserroleid;
$raparents[$CFG->defaultuserroleid][$syscontext->id] = $syscontext->id;
}
// load the "default frontpage role"
if (!empty($CFG->defaultfrontpageroleid)) {
$frontpagecontext = context_course::instance(get_site()->id);
if ($frontpagecontext->path) {
$accessdata['ra'][$frontpagecontext->path][(int)$CFG->defaultfrontpageroleid] = (int)$CFG->defaultfrontpageroleid;
$raparents[$CFG->defaultfrontpageroleid][$frontpagecontext->id] = $frontpagecontext->id;
}
}
// preload every assigned role at and above course context
$sql = "SELECT ctx.path, ra.roleid, ra.contextid
FROM {role_assignments} ra
JOIN {context} ctx
ON ctx.id = ra.contextid
LEFT JOIN {block_instances} bi
ON (ctx.contextlevel = ".CONTEXT_BLOCK." AND bi.id = ctx.instanceid)
LEFT JOIN {context} bpctx
ON (bpctx.id = bi.parentcontextid)
WHERE ra.userid = :userid
AND (ctx.contextlevel <= ".CONTEXT_COURSE." OR bpctx.contextlevel < ".CONTEXT_COURSE.")";
$params = array('userid'=>$userid);
$rs = $DB->get_recordset_sql($sql, $params);
foreach ($rs as $ra) {
// RAs leafs are arrays to support multi-role assignments...
$accessdata['ra'][$ra->path][(int)$ra->roleid] = (int)$ra->roleid;
$raparents[$ra->roleid][$ra->contextid] = $ra->contextid;
}
$rs->close();
if (empty($raparents)) {
return $accessdata;
}
// now get overrides of interesting roles in all interesting child contexts
// hopefully we will not run out of SQL limits here,
// users would have to have very many roles at/above course context...
$sqls = array();
$params = array();
static $cp = 0;
foreach ($raparents as $roleid=>$ras) {
$cp++;
list($sqlcids, $cids) = $DB->get_in_or_equal($ras, SQL_PARAMS_NAMED, 'c'.$cp.'_');
$params = array_merge($params, $cids);
$params['r'.$cp] = $roleid;
$sqls[] = "(SELECT ctx.path, rc.roleid, rc.capability, rc.permission
FROM {role_capabilities} rc
JOIN {context} ctx
ON (ctx.id = rc.contextid)
JOIN {context} pctx
ON (pctx.id $sqlcids
AND (ctx.id = pctx.id
OR ctx.path LIKE ".$DB->sql_concat('pctx.path',"'/%'")."
OR pctx.path LIKE ".$DB->sql_concat('ctx.path',"'/%'")."))
LEFT JOIN {block_instances} bi
ON (ctx.contextlevel = ".CONTEXT_BLOCK." AND bi.id = ctx.instanceid)
LEFT JOIN {context} bpctx
ON (bpctx.id = bi.parentcontextid)
WHERE rc.roleid = :r{$cp}
AND (ctx.contextlevel <= ".CONTEXT_COURSE." OR bpctx.contextlevel < ".CONTEXT_COURSE.")
)";
}
// fixed capability order is necessary for rdef dedupe
$rs = $DB->get_recordset_sql(implode("\nUNION\n", $sqls). "ORDER BY capability", $params);
foreach ($rs as $rd) {
$k = $rd->path.':'.$rd->roleid;
$accessdata['rdef'][$k][$rd->capability] = (int)$rd->permission;
}
$rs->close();
// share the role definitions
foreach ($accessdata['rdef'] as $k=>$unused) {
if (!isset($ACCESSLIB_PRIVATE->rolepermissions[$k])) {
$ACCESSLIB_PRIVATE->rolepermissions[$k] = $accessdata['rdef'][$k];
}
$accessdata['rdef_count']++;
$accessdata['rdef'][$k] =& $ACCESSLIB_PRIVATE->rolepermissions[$k];
}
return $accessdata;
}
/**
* Add to the access ctrl array the data needed by a user for a given course.
*
* This function injects all course related access info into the accessdata array.
*
* @access private
* @param int $userid the id of the user
* @param context_course $coursecontext course context
* @param array $accessdata accessdata array (modified)
* @return void modifies $accessdata parameter
*/
function load_course_context($userid, context_course $coursecontext, &$accessdata) {
global $DB, $CFG, $ACCESSLIB_PRIVATE;
if (empty($coursecontext->path)) {
// weird, this should not happen
return;
}
if (isset($accessdata['loaded'][$coursecontext->instanceid])) {
// already loaded, great!
return;
}
$roles = array();
if (empty($userid)) {
if (!empty($CFG->notloggedinroleid)) {
$roles[$CFG->notloggedinroleid] = $CFG->notloggedinroleid;
}
} else if (isguestuser($userid)) {
if ($guestrole = get_guest_role()) {
$roles[$guestrole->id] = $guestrole->id;
}
} else {
// Interesting role assignments at, above and below the course context
list($parentsaself, $params) = $DB->get_in_or_equal($coursecontext->get_parent_context_ids(true), SQL_PARAMS_NAMED, 'pc_');
$params['userid'] = $userid;
$params['children'] = $coursecontext->path."/%";
$sql = "SELECT ra.*, ctx.path
FROM {role_assignments} ra
JOIN {context} ctx ON ra.contextid = ctx.id
WHERE ra.userid = :userid AND (ctx.id $parentsaself OR ctx.path LIKE :children)";
$rs = $DB->get_recordset_sql($sql, $params);
// add missing role definitions
foreach ($rs as $ra) {
$accessdata['ra'][$ra->path][(int)$ra->roleid] = (int)$ra->roleid;
$roles[$ra->roleid] = $ra->roleid;
}
$rs->close();
// add the "default frontpage role" when on the frontpage
if (!empty($CFG->defaultfrontpageroleid)) {
$frontpagecontext = context_course::instance(get_site()->id);
if ($frontpagecontext->id == $coursecontext->id) {
$roles[$CFG->defaultfrontpageroleid] = $CFG->defaultfrontpageroleid;
}
}
// do not forget the default role
if (!empty($CFG->defaultuserroleid)) {
$roles[$CFG->defaultuserroleid] = $CFG->defaultuserroleid;
}
}
if (!$roles) {
// weird, default roles must be missing...
$accessdata['loaded'][$coursecontext->instanceid] = 1;
return;
}
// now get overrides of interesting roles in all interesting contexts (this course + children + parents)
$params = array('c'=>$coursecontext->id);
list($parentsaself, $rparams) = $DB->get_in_or_equal($coursecontext->get_parent_context_ids(true), SQL_PARAMS_NAMED, 'pc_');
$params = array_merge($params, $rparams);
list($roleids, $rparams) = $DB->get_in_or_equal($roles, SQL_PARAMS_NAMED, 'r_');
$params = array_merge($params, $rparams);
$sql = "SELECT ctx.path, rc.roleid, rc.capability, rc.permission
FROM {role_capabilities} rc
JOIN {context} ctx
ON (ctx.id = rc.contextid)
JOIN {context} cctx
ON (cctx.id = :c
AND (ctx.id $parentsaself OR ctx.path LIKE ".$DB->sql_concat('cctx.path',"'/%'")."))
WHERE rc.roleid $roleids
ORDER BY rc.capability"; // fixed capability order is necessary for rdef dedupe
$rs = $DB->get_recordset_sql($sql, $params);