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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
* - get_context_instance()
* - get_context_instance_by_id()
* - get_parent_contexts()
* - get_child_contexts()
*
* Whether the user can do something...
* - has_capability()
* - has_any_capability()
* - has_all_capabilities()
* - require_capability()
* - require_login() (from moodlelib)
*
* What courses has this user access to?
* - get_user_courses_bycap()
*
* What users can do X in this context?
* - get_users_by_capability()
*
* Enrol/unenrol
* - enrol_into_course()
* - role_assign()/role_unassign()
*
*
* Advanced use
* - load_all_capabilities()
* - reload_all_capabilities()
* - has_capability_in_accessdata()
* - is_siteadmin()
* - get_user_access_sitewide()
* - load_subcontext()
* - get_role_access_bycontext()
*
* <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($roleid)
* [$contextpath]= array($roleid)
* [$contextpath]= array($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/down the tree.
*
* Normally - specially for the logged-in user, 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>
* $accessdata[loaded] = array($contextpath, $contextpath)
* </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 sytem 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 moodlecore
* @copyright 1999 onwards Martin Dougiamas http://dougiamas.com
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
/** permission definitions */
define('CAP_INHERIT', 0);
/** permission definitions */
define('CAP_ALLOW', 1);
/** permission definitions */
define('CAP_PREVENT', -1);
/** permission definitions */
define('CAP_PROHIBIT', -1000);
/** context definitions */
define('CONTEXT_SYSTEM', 10);
/** context definitions */
define('CONTEXT_USER', 30);
/** context definitions */
define('CONTEXT_COURSECAT', 40);
/** context definitions */
define('CONTEXT_COURSE', 50);
/** context definitions */
define('CONTEXT_MODULE', 70);
/** context definitions */
define('CONTEXT_BLOCK', 80);
/** capability risks - see {@link http://docs.moodle.org/en/Development:Hardening_new_Roles_system} */
define('RISK_MANAGETRUST', 0x0001);
/** capability risks - see {@link http://docs.moodle.org/en/Development:Hardening_new_Roles_system} */
define('RISK_CONFIG', 0x0002);
/** capability risks - see {@link http://docs.moodle.org/en/Development:Hardening_new_Roles_system} */
define('RISK_XSS', 0x0004);
/** capability risks - see {@link http://docs.moodle.org/en/Development:Hardening_new_Roles_system} */
define('RISK_PERSONAL', 0x0008);
/** capability risks - see {@link http://docs.moodle.org/en/Development:Hardening_new_Roles_system} */
define('RISK_SPAM', 0x0010);
/** capability risks - see {@link http://docs.moodle.org/en/Development:Hardening_new_Roles_system} */
define('RISK_DATALOSS', 0x0020);
/** rolename displays - the name as defined in the role definition */
define('ROLENAME_ORIGINAL', 0);
/** rolename displays - the name as defined by a role alias */
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);
/** size limit for context cache */
if (!defined('MAX_CONTEXT_CACHE_SIZE')) {
define('MAX_CONTEXT_CACHE_SIZE', 5000);
}
/**
* 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 variale is the only way to impleemnt this, withough rewriting everything
* as methods of a class, instead of functions.
*
* @global stdClass $ACCESSLIB_PRIVATE
* @name $ACCESSLIB_PRIVATE
*/
$ACCESSLIB_PRIVATE = new stdClass;
$ACCESSLIB_PRIVATE->contexts = array(); // Cache of context objects by level and instance
$ACCESSLIB_PRIVATE->contextsbyid = array(); // Cache of context objects by id
$ACCESSLIB_PRIVATE->systemcontext = null; // Used in get_system_context
$ACCESSLIB_PRIVATE->dirtycontexts = null; // Dirty contexts cache
$ACCESSLIB_PRIVATE->accessdatabyuser = array(); // Holds the $accessdata structure for users other than $USER
$ACCESSLIB_PRIVATE->roledefinitions = array(); // role definitions cache - helps a lot with mem usage in cron
$ACCESSLIB_PRIVATE->croncache = array(); // Used in get_role_access
$ACCESSLIB_PRIVATE->preloadedcourses = array(); // Used in preload_course_contexts.
$ACCESSLIB_PRIVATE->capabilitynames = null; // Used in is_valid_capability (only in developer debug mode)
/**
* 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 fo the tests.
* @global object
* @global object
* @global object
*/
function accesslib_clear_all_caches_for_unit_testing() {
global $UNITTEST, $USER, $ACCESSLIB_PRIVATE;
if (empty($UNITTEST->running)) {
throw new coding_exception('You must not call clear_all_caches outside of unit tests.');
}
$ACCESSLIB_PRIVATE->contexts = array();
$ACCESSLIB_PRIVATE->contextsbyid = array();
$ACCESSLIB_PRIVATE->systemcontext = null;
$ACCESSLIB_PRIVATE->dirtycontexts = null;
$ACCESSLIB_PRIVATE->accessdatabyuser = array();
$ACCESSLIB_PRIVATE->roledefinitions = array();
$ACCESSLIB_PRIVATE->croncache = array();
$ACCESSLIB_PRIVATE->preloadedcourses = array();
$ACCESSLIB_PRIVATE->capabilitynames = null;
unset($USER->access);
}
/**
* Private function. Add a context object to accesslib's caches.
* @global object
* @param object $context
*/
function cache_context($context) {
global $ACCESSLIB_PRIVATE;
// If there are too many items in the cache already, remove items until
// there is space
while (count($ACCESSLIB_PRIVATE->contextsbyid) >= MAX_CONTEXT_CACHE_SIZE) {
$first = reset($ACCESSLIB_PRIVATE->contextsbyid);
unset($ACCESSLIB_PRIVATE->contextsbyid[$first->id]);
unset($ACCESSLIB_PRIVATE->contexts[$first->contextlevel][$first->instanceid]);
}
$ACCESSLIB_PRIVATE->contexts[$context->contextlevel][$context->instanceid] = $context;
$ACCESSLIB_PRIVATE->contextsbyid[$context->id] = $context;
}
/**
* This is really slow!!! do not use above course context level
*
* @global object
* @param int $roleid
* @param object $context
* @return array
*/
function get_role_context_caps($roleid, $context) {
global $DB;
//this is really slow!!!! - do not use above course context level!
$result = array();
$result[$context->id] = array();
// first emulate the parent context capabilities merging into context
$searchcontexts = array_reverse(get_parent_contexts($context));
array_push($searchcontexts, $context->id);
foreach ($searchcontexts as $cid) {
if ($capabilities = $DB->get_records('role_capabilities', array('roleid'=>$roleid, 'contextid'=>$cid))) {
foreach ($capabilities as $cap) {
if (!array_key_exists($cap->capability, $result[$context->id])) {
$result[$context->id][$cap->capability] = 0;
}
$result[$context->id][$cap->capability] += $cap->permission;
}
}
}
// now go through the contexts bellow given context
$searchcontexts = array_keys(get_child_contexts($context));
foreach ($searchcontexts as $cid) {
if ($capabilities = $DB->get_records('role_capabilities', array('roleid'=>$roleid, 'contextid'=>$cid))) {
foreach ($capabilities as $cap) {
if (!array_key_exists($cap->contextid, $result)) {
$result[$cap->contextid] = array();
}
$result[$cap->contextid][$cap->capability] = $cap->permission;
}
}
}
return $result;
}
/**
* Gets the accessdata for role "sitewide" (system down to course)
*
* @global object
* @global object
* @param int $roleid
* @param array $accessdata defaults to null
* @return array
*/
function get_role_access($roleid, $accessdata=NULL) {
global $CFG, $DB;
/* Get it in 1 cheap DB query...
* - relevant role caps at the root and down
* to the course level - but not below
*/
if (is_null($accessdata)) {
$accessdata = array(); // named list
$accessdata['ra'] = array();
$accessdata['rdef'] = array();
$accessdata['loaded'] = array();
}
//
// 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
WHERE rc.roleid = ?
AND ctx.contextlevel <= ".CONTEXT_COURSE."
ORDER BY ctx.depth, ctx.path";
$params = array($roleid);
// we need extra caching in CLI scripts and cron
if (CLI_SCRIPT) {
global $ACCESSLIB_PRIVATE;
if (!isset($ACCESSLIB_PRIVATE->croncache[$roleid])) {
$ACCESSLIB_PRIVATE->croncache[$roleid] = array();
if ($rs = $DB->get_recordset_sql($sql, $params)) {
foreach ($rs as $rd) {
$ACCESSLIB_PRIVATE->croncache[$roleid][] = $rd;
}
$rs->close();
}
}
foreach ($ACCESSLIB_PRIVATE->croncache[$roleid] as $rd) {
$k = "{$rd->path}:{$roleid}";
$accessdata['rdef'][$k][$rd->capability] = $rd->permission;
}
} else {
if ($rs = $DB->get_recordset_sql($sql, $params)) {
foreach ($rs as $rd) {
$k = "{$rd->path}:{$roleid}";
$accessdata['rdef'][$k][$rd->capability] = $rd->permission;
}
unset($rd);
$rs->close();
}
}
return $accessdata;
}
/**
* Gets the accessdata for role "sitewide" (system down to course)
*
* @global object
* @global object
* @param int $roleid
* @param array $accessdata defaults to null
* @return array
*/
function get_default_frontpage_role_access($roleid, $accessdata=NULL) {
global $CFG, $DB;
$frontpagecontext = get_context_instance(CONTEXT_COURSE, SITEID);
$base = '/'. SYSCONTEXTID .'/'. $frontpagecontext->id;
//
// Overrides for the role in any contexts related to the course
//
$sql = "SELECT ctx.path,
rc.capability, rc.permission
FROM {context} ctx
JOIN {role_capabilities} rc
ON rc.contextid=ctx.id
WHERE rc.roleid = ?
AND (ctx.id = ".SYSCONTEXTID." OR ctx.path LIKE ?)
AND ctx.contextlevel <= ".CONTEXT_COURSE."
ORDER BY ctx.depth, ctx.path";
$params = array($roleid, "$base/%");
if ($rs = $DB->get_recordset_sql($sql, $params)) {
foreach ($rs as $rd) {
$k = "{$rd->path}:{$roleid}";
$accessdata['rdef'][$k][$rd->capability] = $rd->permission;
}
unset($rd);
$rs->close();
}
return $accessdata;
}
/**
* Get the default guest role
*
* @global object
* @global object
* @return object role
*/
function get_guest_role() {
global $CFG, $DB;
if (empty($CFG->guestroleid)) {
if ($roles = get_roles_with_capability('moodle/legacy:guest', CAP_ALLOW)) {
$guestrole = array_shift($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 paritcular capability in a given context.
*
* For example::
* $context = get_context_instance(CONTEXT_MODULE, $cm->id);
* has_capability('mod/forum:replypost',$context)
*
* By default checks the capabilties of the current user, but you can pass a
* different userid. By default will return true for admin-like users who have the
* moodle/site:doanything capability, but you can override that with the fourth argument.
*
* @param string $capability the name of the capability to check. For example mod/forum:view
* @param object $context the context to check the capability in. You normally get this with {@link get_context_instance}.
* @param integer $userid A user id. By default (null) checks the permissions of the current user.
* @param boolean $doanything If false, ignore the special moodle/site:doanything capability that admin-like roles have.
* @return boolean true if the user has this capability. Otherwise false.
*/
function has_capability($capability, $context, $userid=NULL, $doanything=true) {
global $USER, $CFG, $DB, $SCRIPT, $ACCESSLIB_PRIVATE;
if (during_initial_install()) {
if ($SCRIPT === "/$CFG->admin/index.php" or $SCRIPT === "/$CFG->admin/cliupgrade.php") {
// we are in an installer - roles can not work yet
return true;
} else {
return false;
}
}
// the original $CONTEXT here was hiding serious errors
// for security reasons do not reuse previous context
if (empty($context)) {
debugging('Incorrect context specified');
return false;
}
/// Some sanity checks
if (debugging('',DEBUG_DEVELOPER)) {
if (!is_valid_capability($capability)) {
debugging('Capability "'.$capability.'" was not found! This should be fixed in code.');
}
if (!is_bool($doanything)) {
debugging('Capability parameter "doanything" is wierd ("'.$doanything.'"). This should be fixed in code.');
}
}
if (empty($userid)) { // we must accept null, 0, '0', '' etc. in $userid
if (empty($USER->id)) {
// Session not set up yet.
$userid = 0;
} else {
$userid = $USER->id;
}
}
if (is_null($context->path) or $context->depth == 0) {
//this should not happen
$contexts = array(SYSCONTEXTID, $context->id);
$context->path = '/'.SYSCONTEXTID.'/'.$context->id;
debugging('Context id '.$context->id.' does not have valid path, please use build_context_path()', DEBUG_DEVELOPER);
} else {
$contexts = explode('/', $context->path);
array_shift($contexts);
}
if (CLI_SCRIPT && !isset($USER->access)) {
// In cron, some modules setup a 'fake' $USER,
// ensure we load the appropriate accessdata.
if (isset($ACCESSLIB_PRIVATE->accessdatabyuser[$userid])) {
$ACCESSLIB_PRIVATE->dirtycontexts = NULL; //load fresh dirty contexts
} else {
load_user_accessdata($userid);
$ACCESSLIB_PRIVATE->dirtycontexts = array();
}
$USER->access = $ACCESSLIB_PRIVATE->accessdatabyuser[$userid];
} else if (isset($USER->id) && ($USER->id == $userid) && !isset($USER->access)) {
// caps not loaded yet - better to load them to keep BC with 1.8
// not-logged-in user or $USER object set up manually first time here
load_all_capabilities();
$ACCESSLIB_PRIVATE->accessdatabyuser = array(); // reset the cache for other users too, the dirty contexts are empty now
$ACCESSLIB_PRIVATE->roledefinitions = array();
}
// Load dirty contexts list if needed
if (!isset($ACCESSLIB_PRIVATE->dirtycontexts)) {
if (isset($USER->access['time'])) {
$ACCESSLIB_PRIVATE->dirtycontexts = get_dirty_contexts($USER->access['time']);
}
else {
$ACCESSLIB_PRIVATE->dirtycontexts = array();
}
}
// Careful check for staleness...
if (count($ACCESSLIB_PRIVATE->dirtycontexts) !== 0 and is_contextpath_dirty($contexts, $ACCESSLIB_PRIVATE->dirtycontexts)) {
// reload all capabilities - preserving loginas, roleswitches, etc
// and then cleanup any marks of dirtyness... at least from our short
// term memory! :-)
$ACCESSLIB_PRIVATE->accessdatabyuser = array();
$ACCESSLIB_PRIVATE->roledefinitions = array();
if (CLI_SCRIPT) {
load_user_accessdata($userid);
$USER->access = $ACCESSLIB_PRIVATE->accessdatabyuser[$userid];
$ACCESSLIB_PRIVATE->dirtycontexts = array();
} else {
reload_all_capabilities();
}
}
// divulge how many times we are called
//// error_log("has_capability: id:{$context->id} path:{$context->path} userid:$userid cap:$capability");
if (isset($USER->id) && ($USER->id == $userid)) { // we must accept strings and integers in $userid
//
// For the logged in user, we have $USER->access
// which will have all RAs and caps preloaded for
// course and above contexts.
//
// Contexts below courses && contexts that do not
// hang from courses are loaded into $USER->access
// on demand, and listed in $USER->access[loaded]
//
if ($context->contextlevel <= CONTEXT_COURSE) {
// Course and above are always preloaded
return has_capability_in_accessdata($capability, $context, $USER->access, $doanything);
}
// Load accessdata for below-the-course contexts
if (!path_inaccessdata($context->path,$USER->access)) {
// error_log("loading access for context {$context->path} for $capability at {$context->contextlevel} {$context->id}");
// $bt = debug_backtrace();
// error_log("bt {$bt[0]['file']} {$bt[0]['line']}");
load_subcontext($USER->id, $context, $USER->access);
}
return has_capability_in_accessdata($capability, $context, $USER->access, $doanything);
}
if (!isset($ACCESSLIB_PRIVATE->accessdatabyuser[$userid])) {
load_user_accessdata($userid);
}
if ($context->contextlevel <= CONTEXT_COURSE) {
// Course and above are always preloaded
return has_capability_in_accessdata($capability, $context, $ACCESSLIB_PRIVATE->accessdatabyuser[$userid], $doanything);
}
// Load accessdata for below-the-course contexts as needed
if (!path_inaccessdata($context->path, $ACCESSLIB_PRIVATE->accessdatabyuser[$userid])) {
// error_log("loading access for context {$context->path} for $capability at {$context->contextlevel} {$context->id}");
// $bt = debug_backtrace();
// error_log("bt {$bt[0]['file']} {$bt[0]['line']}");
load_subcontext($userid, $context, $ACCESSLIB_PRIVATE->accessdatabyuser[$userid]);
}
return has_capability_in_accessdata($capability, $context, $ACCESSLIB_PRIVATE->accessdatabyuser[$userid], $doanything);
}
/**
* 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.
*
* There are probably tricks that could be done to improve the performance here, for example,
* check the capabilities that are already cached first.
*
* @see has_capability()
* @param array $capabilities an array of capability names.
* @param object $context the context to check the capability in. You normally get this with {@link get_context_instance}.
* @param integer $userid A user id. By default (null) checks the permissions of the current user.
* @param boolean $doanything If false, ignore the special moodle/site:doanything capability that admin-like roles have.
* @return boolean true if the user has any of these capabilities. Otherwise false.
*/
function has_any_capability($capabilities, $context, $userid=NULL, $doanything=true) {
if (!is_array($capabilities)) {
debugging('Incorrect $capabilities parameter in has_any_capabilities() call - must be an array');
return false;
}
foreach ($capabilities as $capability) {
if (has_capability($capability, $context, $userid, $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.
*
* There are probably tricks that could be done to improve the performance here, for example,
* check the capabilities that are already cached first.
*
* @see has_capability()
* @param array $capabilities an array of capability names.
* @param object $context the context to check the capability in. You normally get this with {@link get_context_instance}.
* @param integer $userid A user id. By default (null) checks the permissions of the current user.
* @param boolean $doanything If false, ignore the special moodle/site:doanything capability that admin-like roles have.
* @return boolean true if the user has all of these capabilities. Otherwise false.
*/
function has_all_capabilities($capabilities, $context, $userid=NULL, $doanything=true) {
if (!is_array($capabilities)) {
debugging('Incorrect $capabilities parameter in has_all_capabilities() call - must be an array');
return false;
}
foreach ($capabilities as $capability) {
if (!has_capability($capability, $context, $userid, $doanything)) {
return false;
}
}
return true;
}
/**
* Check if the user is an admin at the site level
*
* Uses 1 DB query to answer whether a user is an admin at the sitelevel.
* It depends on DB schema >=1.7 but does not depend on the new datastructures
* in v1.9 (context.path, or $USER->access)
*
* Will return true if the userid has any of
* - moodle/site:config
* - moodle/legacy:admin
* - moodle/site:doanything
*
* @global object
* @global object
* @param int $userid
* @returns bool true is user can administer server settings
*/
function is_siteadmin($userid) {
global $CFG, $DB;
$sql = "SELECT SUM(rc.permission)
FROM {role_capabilities} rc
JOIN {context} ctx
ON ctx.id=rc.contextid
JOIN {role_assignments} ra
ON ra.roleid=rc.roleid AND ra.contextid=ctx.id
WHERE ctx.contextlevel=10
AND ra.userid=?
AND rc.capability IN (?, ?, ?)
GROUP BY rc.capability
HAVING SUM(rc.permission) > 0";
$params = array($userid, 'moodle/site:config', 'moodle/legacy:admin', 'moodle/site:doanything');
return $DB->record_exists_sql($sql, $params);
}
/**
* Check whether a role is an admin at the site level
*
* Will return true if the userid has any of
* - moodle/site:config
* - moodle/legacy:admin
* - moodle/site:doanything
*
* @global object
* @param integer $roleid a role id.
* @return boolean, whether this role is an admin role.
*/
function is_admin_role($roleid) {
global $DB;
$sql = "SELECT 1
FROM {role_capabilities} rc
JOIN {context} ctx ON ctx.id = rc.contextid
WHERE ctx.contextlevel = 10
AND rc.roleid = ?
AND rc.capability IN (?, ?, ?)
GROUP BY rc.capability
HAVING SUM(rc.permission) > 0";
$params = array($roleid, 'moodle/site:config', 'moodle/legacy:admin', 'moodle/site:doanything');
return $DB->record_exists_sql($sql, $params);
}
/**
* Returns all the roles for which is_admin_role($role->id) is true.
*
* @global object
* @return array
*/
function get_admin_roles() {
global $DB;
$sql = "SELECT *
FROM {role} r
WHERE EXISTS (
SELECT 1
FROM {role_capabilities} rc
JOIN {context} ctx ON ctx.id = rc.contextid
WHERE ctx.contextlevel = 10
AND rc.roleid = r.id
AND rc.capability IN (?, ?, ?)
GROUP BY rc.capability
HAVING SUM(rc.permission) > 0
)
ORDER BY r.sortorder";
$params = array('moodle/site:config', 'moodle/legacy:admin', 'moodle/site:doanything');
return $DB->get_records_sql($sql, $params);
}
/**
* @param string $path
* @return string
*/
function get_course_from_path ($path) {
// assume that nothing is more than 1 course deep
if (preg_match('!^(/.+)/\d+$!', $path, $matches)) {
return $matches[1];
}
return false;
}
/**
* @param string $path
* @param array $accessdata
* @return bool
*/
function path_inaccessdata($path, $accessdata) {
// assume that contexts hang from sys or from a course
// this will only work well with stuff that hangs from a course
if (in_array($path, $accessdata['loaded'], true)) {
// error_log("found it!");
return true;
}
$base = '/' . SYSCONTEXTID;
while (preg_match('!^(/.+)/\d+$!', $path, $matches)) {
$path = $matches[1];
if ($path === $base) {
return false;
}
if (in_array($path, $accessdata['loaded'], true)) {
return true;
}
}
return false;
}
/**
*
* Walk the accessdata array and return true/false
*
* Walk the accessdata array and return true/false.
* Deals with prohibits, roleswitching, aggregating
* capabilities, etc.
*
* The main feature of here is being FAST and with no
* side effects.
*
* Notes:
*
* Switch Roles exits early
* -----------------------
* cap checks within a switchrole need to exit early
* in our bottom up processing so they don't "see" that
* there are real RAs that can do all sorts of things.
*
* 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.
*
* Local-most role definition and role-assignment wins
* ---------------------------------------------------
* So if the local context has said 'allow', it wins
* over a high-level context that says 'deny'.
* This is applied when walking rdefs, and RAs.
* Only at the same context the values are SUM()med.
*
* The exception is CAP_PROHIBIT.
*
* "Guest default role" exception
* ------------------------------
*
* See MDL-7513 and $ignoreguest below for details.
*
* The rule is that
*
* IF we are being asked about moodle/legacy:guest
* OR moodle/course:view
* FOR a real, logged-in user
* AND we reached the top of the path in ra and rdef
* AND that role has moodle/legacy:guest === 1...
* THEN we act as if we hadn't seen it.
*
* Note that this function must be kept in synch with has_capability_in_accessdata.
*
* To Do:
* @todo Document how it works
* @todo Rewrite in ASM
*
* @global object
* @param string $capability
* @param object $context
* @param array $accessdata
* @param bool $doanything
* @return bool
*/
function has_capability_in_accessdata($capability, $context, $accessdata, $doanything) {
global $CFG;
$path = $context->path;
// build $contexts as a list of "paths" of the current
// contexts and parents with the order top-to-bottom
$contexts = array($path);
while (preg_match('!^(/.+)/\d+$!', $path, $matches)) {
$path = $matches[1];
array_unshift($contexts, $path);
}
$ignoreguest = false;
if (isset($accessdata['dr'])
&& ($capability == 'moodle/course:view'
|| $capability == 'moodle/legacy:guest')) {
// At the base, ignore rdefs where moodle/legacy:guest
// is set
$ignoreguest = $accessdata['dr'];
}
// Coerce it to an int
$CAP_PROHIBIT = (int)CAP_PROHIBIT;
$cc = count($contexts);
$can = 0;
$capdepth = 0;
//
// role-switches loop
//
if (isset($accessdata['rsw'])) {
// check for isset() is fast
// empty() is slow...
if (empty($accessdata['rsw'])) {
unset($accessdata['rsw']); // keep things fast and unambiguous
break;
}
// From the bottom up...
for ($n=$cc-1;$n>=0;$n--) {
$ctxp = $contexts[$n];
if (isset($accessdata['rsw'][$ctxp])) {
// Found a switchrole assignment
// check for that role _plus_ the default user role
$ras = array($accessdata['rsw'][$ctxp],$CFG->defaultuserroleid);
for ($rn=0;$rn<2;$rn++) {
$roleid = (int)$ras[$rn];
// Walk the path for capabilities
// from the bottom up...
for ($m=$cc-1;$m>=0;$m--) {
$capctxp = $contexts[$m];
if (isset($accessdata['rdef']["{$capctxp}:$roleid"][$capability])) {
$perm = (int)$accessdata['rdef']["{$capctxp}:$roleid"][$capability];
// The most local permission (first to set) wins
// the only exception is CAP_PROHIBIT
if ($can === 0) {
$can = $perm;
} elseif ($perm === $CAP_PROHIBIT) {
$can = $perm;
break;
}
}
}
}
// As we are dealing with a switchrole,
// we return _here_, do _not_ walk up
// the hierarchy any further
if ($can < 1) {
if ($doanything) {
// didn't find it as an explicit cap,
// but maybe the user can doanything in this context...
return has_capability_in_accessdata('moodle/site:doanything', $context, $accessdata, false);
} else {
return false;
}
} else {
return true;
}
}
}
}
//
// Main loop for normal RAs
// From the bottom up...
//
for ($n=$cc-1;$n>=0;$n--) {
$ctxp = $contexts[$n];
if (isset($accessdata['ra'][$ctxp])) {
// Found role assignments on this leaf
$ras = $accessdata['ra'][$ctxp];
$rc = count($ras);
$ctxcan = 0;
$ctxcapdepth = 0;
for ($rn=0;$rn<$rc;$rn++) {
$roleid = (int)$ras[$rn];
$rolecan = 0;
$rolecapdepth = 0;
// Walk the path for capabilities
// from the bottom up...
for ($m=$cc-1;$m>=0;$m--) {
$capctxp = $contexts[$m];
// ignore some guest caps
// at base ra and rdef
if ($ignoreguest == $roleid
&& $n === 0
&& $m === 0
&& isset($accessdata['rdef']["{$capctxp}:$roleid"]['moodle/legacy:guest'])
&& $accessdata['rdef']["{$capctxp}:$roleid"]['moodle/legacy:guest'] > 0) {
continue;
}
if (isset($accessdata['rdef']["{$capctxp}:$roleid"][$capability])) {
$perm = (int)$accessdata['rdef']["{$capctxp}:$roleid"][$capability];
// The most local permission (first to set) wins
// the only exception is CAP_PROHIBIT
if ($rolecan === 0) {
$rolecan = $perm;
$rolecapdepth = $m;
} elseif ($perm === $CAP_PROHIBIT) {
$rolecan = $perm;
$rolecapdepth = $m;
break;
}
}
}
// Rules for RAs at the same context...
// - prohibits always wins
// - permissions at the same ctxlevel & capdepth are added together
// - deeper capdepth wins
if ($ctxcan === $CAP_PROHIBIT || $rolecan === $CAP_PROHIBIT) {
$ctxcan = $CAP_PROHIBIT;
$ctxcapdepth = 0;
} elseif ($ctxcapdepth === $rolecapdepth) {
$ctxcan += $rolecan;
} elseif ($ctxcapdepth < $rolecapdepth) {
$ctxcan = $rolecan;
$ctxcapdepth = $rolecapdepth;
} else { // ctxcaptdepth is deeper
// rolecap ignored
}
}
// The most local RAs with a defined
// permission ($ctxcan) win, except
// for CAP_PROHIBIT
// NOTE: If we want the deepest RDEF to
// win regardless of the depth of the RA,
// change the elseif below to read
// ($can === 0 || $capdepth < $ctxcapdepth) {
if ($ctxcan === $CAP_PROHIBIT) {
$can = $ctxcan;
break;