/* * \brief Representation used for children of the init process * \author Norman Feske * \date 2010-05-04 */ /* * Copyright (C) 2010-2013 Genode Labs GmbH * * This file is part of the Genode OS framework, which is distributed * under the terms of the GNU General Public License version 2. */ #ifndef _INCLUDE__INIT__CHILD_H_ #define _INCLUDE__INIT__CHILD_H_ /* Genode includes */ #include #include #include #include #include /* init includes */ #include #include namespace Init { extern bool config_verbose; /*************** ** Utilities ** ***************/ inline long read_priority(Genode::Xml_node start_node) { long priority = Genode::Cpu_session::DEFAULT_PRIORITY; try { start_node.attribute("priority").value(&priority); } catch (...) { } /* * All priority declarations in the config file are * negative because child priorities can never be higher * than parent priorities. To simplify priority * calculations, we use inverted values. Lower values * correspond to higher priorities. */ return -priority; } inline Genode::Affinity::Location read_affinity_location(Genode::Affinity::Space const &space, Genode::Xml_node start_node) { typedef Genode::Affinity::Location Location; try { Genode::Xml_node node = start_node.sub_node("affinity"); /* if no position value is specified, select the whole row/column */ unsigned long const default_width = node.has_attribute("xpos") ? 1 : space.width(), default_height = node.has_attribute("ypos") ? 1 : space.height(); unsigned long const width = node.attribute_value("width", default_width), height = node.attribute_value("height", default_height); long const x1 = node.attribute_value("xpos", 0), y1 = node.attribute_value("ypos", 0), x2 = x1 + width - 1, y2 = y1 + height - 1; /* clip location to space boundary */ return Location(Genode::max(x1, 0L), Genode::max(y1, 0L), Genode::min((unsigned)(x2 - x1 + 1), space.width()), Genode::min((unsigned)(y2 - y1 + 1), space.height())); } catch (...) { return Location(0, 0, space.width(), space.height()); } } /** * Return amount of RAM that is currently unused */ static inline Genode::size_t avail_slack_ram_quota() { Genode::size_t const preserve = 128*1024; Genode::size_t const avail = Genode::env()->ram_session()->avail(); return avail > preserve ? avail - preserve : 0; } inline Genode::size_t read_ram_quota(Genode::Xml_node start_node) { Genode::Number_of_bytes ram_quota = 0; try { Genode::Xml_node rsc = start_node.sub_node("resource"); for (;; rsc = rsc.next("resource")) { try { if (rsc.attribute("name").has_value("RAM")) { rsc.attribute("quantum").value(&ram_quota); } } catch (...) { } } } catch (...) { } /* * If the configured quota exceeds our own quota, we donate * all remaining quota to the child but we need to count in * our allocation of the child meta data from the heap. * Hence, we preserve some of our own quota. */ if (ram_quota > avail_slack_ram_quota()) { ram_quota = avail_slack_ram_quota(); if (config_verbose) Genode::printf("Warning: Specified quota exceeds available quota.\n" " Proceeding with a quota of %zu bytes.\n", (Genode::size_t)ram_quota); } return ram_quota; } /** * Return true if service XML node matches the specified service name */ inline bool service_node_matches(Genode::Xml_node service_node, const char *service_name) { if (service_node.has_type("any-service")) return true; return service_node.has_type("service") && service_node.attribute("name").has_value(service_name); } /** * Return sub string of label with the leading child name stripped out * */ inline char const *skip_label_prefix(char const *child_name, char const *label) { Genode::size_t const child_name_len = Genode::strlen(child_name); /* * If the function was called with a valid "label" string, the * following condition should be always satisfied. See the * comment in 'service_node_args_condition_satisfied'. */ if (Genode::strcmp(child_name, label, child_name_len) == 0) label += child_name_len; /* * If the original label was empty, the 'Child_policy_enforce_labeling' * does not append a label separator after the child-name prefix. In * this case, we resulting label is empty. */ if (*label == 0) return label; /* * Skip label separator. This condition should be always satisfied. */ if (Genode::strcmp(" -> ", label, 4) == 0) return label + 4; PWRN("cannot skip label prefix while processing "); return label; } /** * Check if arguments satisfy the condition specified for the route */ inline bool service_node_args_condition_satisfied(Genode::Xml_node service_node, const char *args, char const *child_name) { try { Genode::Xml_node if_arg = service_node.sub_node("if-arg"); enum { KEY_MAX_LEN = 64, VALUE_MAX_LEN = 64 }; char key[KEY_MAX_LEN]; char value[VALUE_MAX_LEN]; if_arg.attribute("key").value(key, sizeof(key)); if_arg.attribute("value").value(value, sizeof(value)); char arg_value[VALUE_MAX_LEN]; Genode::Arg_string::find_arg(args, key).string(arg_value, sizeof(arg_value), ""); /* * Skip child-name prefix if the key is the process "label". * * Because 'filter_session_args' is called prior the call of * 'resolve_session_request' from the 'Child::session' function, * 'args' contains the filtered arguments, in particular the label * prefixed with the child's name. For the 'if-args' declaration, * however, we want to omit specifying this prefix because the * session route is specific to the named start node anyway. So * the prefix information is redundant. */ if (Genode::strcmp("label", key) == 0) return Genode::strcmp(value, skip_label_prefix(child_name, arg_value)) == 0; return Genode::strcmp(value, arg_value) == 0; } catch (...) { } /* if no if-arg node exists, the condition is met */ return true; } /** * Init-specific representation of a child service * * For init, we introduce this 'Service' variant that distinguishes two * phases, declared and announced. A 'Routed_service' object is created * when a '' declaration is found in init's configuration. * At that time, however, no children including the server do yet exist. * If, at this stage, a client tries to open a session to this service, * the client get enqueued in a list of applicants and blocked. When * the server officially announces its service and passes over the root * capability, the 'Routed_service' enters the announced stage and any * applicants get unblocked. */ class Routed_service : public Genode::Service { private: Genode::Root_capability _root; bool _announced; Genode::Server *_server; struct Applicant : public Genode::Cancelable_lock, public Genode::List::Element { Applicant() : Cancelable_lock(Genode::Lock::LOCKED) { } }; Genode::Lock _applicants_lock; Genode::List _applicants; public: /** * Constructor * * \param name name of service * \param server server providing the service */ Routed_service(const char *name, Genode::Server *server) : Service(name), _announced(false), _server(server) { } Genode::Server *server() const { return _server; } void announce(Genode::Root_capability root) { Genode::Lock::Guard guard(_applicants_lock); _root = root; _announced = true; /* wake up aspiring clients */ for (Applicant *a; (a = _applicants.first()); ) { _applicants.remove(a); a->unlock(); } } Genode::Session_capability session(const char *args, Genode::Affinity const &affinity) { /* * This function is called from the context of the client's * activation thread. If the service is not yet announced, * we let the client block. */ _applicants_lock.lock(); if (!_announced) { Applicant myself; _applicants.insert(&myself); _applicants_lock.unlock(); myself.lock(); } else _applicants_lock.unlock(); Genode::Session_capability cap; try { cap = Genode::Root_client(_root).session(args, affinity); } catch (Genode::Root::Invalid_args) { throw Invalid_args(); } catch (Genode::Root::Unavailable) { throw Unavailable(); } catch (Genode::Root::Quota_exceeded) { throw Quota_exceeded(); } catch (Genode::Ipc_error) { throw Unavailable(); } if (!cap.valid()) throw Unavailable(); return cap; } void upgrade(Genode::Session_capability sc, const char *args) { try { Genode::Root_client(_root).upgrade(sc, args); } catch (Genode::Root::Invalid_args) { throw Invalid_args(); } catch (Genode::Ipc_error) { throw Unavailable(); } } void close(Genode::Session_capability sc) { try { Genode::Root_client(_root).close(sc); } catch (Genode::Ipc_error) { throw Genode::Blocking_canceled(); } } }; /** * Interface for name database */ struct Name_registry { virtual ~Name_registry() { } /** * Check if specified name is unique * * \return false if name already exists */ virtual bool is_unique(const char *name) const = 0; /** * Find server with specified name */ virtual Genode::Server *lookup_server(const char *name) const = 0; }; class Child_registry; class Child : Genode::Child_policy { public: /** * Exception type */ class Child_name_is_not_unique { }; private: friend class Child_registry; Genode::List_element _list_element; Genode::Xml_node _start_node; Genode::Xml_node _default_route_node; Name_registry *_name_registry; /** * Unique child name and file name of ELF binary */ struct Name { enum { MAX_NAME_LEN = 64 }; char file[MAX_NAME_LEN]; char unique[MAX_NAME_LEN]; /** * Constructor * * Obtains file name and unique process name from XML node * * \param start_node XML start node * \param registry registry tracking unique names */ Name(Genode::Xml_node start_node, Name_registry const *registry) { try { start_node.attribute("name").value(unique, sizeof(unique)); } catch (Genode::Xml_node::Nonexistent_attribute) { PWRN("Missing 'name' attribute in '' entry.\n"); throw; } /* check for a name confict with the other children */ if (!registry->is_unique(unique)) { PERR("Child name \"%s\" is not unique", unique); throw Child_name_is_not_unique(); } /* use name as default file name if not declared otherwise */ Genode::strncpy(file, unique, sizeof(file)); /* check for a binary declaration */ try { Genode::Xml_node binary = start_node.sub_node("binary"); binary.attribute("name").value(file, sizeof(file)); } catch (...) { } } } _name; /** * Platform-specific PD-session arguments */ struct Pd_args : Genode::Native_pd_args { Pd_args(Genode::Xml_node start_node); } _pd_args; /** * Resources assigned to the child */ struct Resources { long prio_levels_log2; long priority; Genode::Affinity affinity; Genode::size_t ram_quota; Genode::Ram_connection ram; Genode::Cpu_connection cpu; Genode::Rm_connection rm; Resources(Genode::Xml_node start_node, const char *label, long prio_levels_log2, Genode::Affinity::Space const &affinity_space) : prio_levels_log2(prio_levels_log2), priority(read_priority(start_node)), affinity(affinity_space, read_affinity_location(affinity_space, start_node)), ram_quota(read_ram_quota(start_node)), ram(label), cpu(label, priority*(Genode::Cpu_session::PRIORITY_LIMIT >> prio_levels_log2), affinity) { /* deduce session costs from usable ram quota */ Genode::size_t session_donations = Genode::Rm_connection::RAM_QUOTA + Genode::Cpu_connection::RAM_QUOTA + Genode::Ram_connection::RAM_QUOTA; if (ram_quota > session_donations) ram_quota -= session_donations; else ram_quota = 0; ram.ref_account(Genode::env()->ram_session_cap()); Genode::env()->ram_session()->transfer_quota(ram.cap(), ram_quota); } } _resources; /* * Entry point used for serving the parent interface and the * locally provided ROM sessions for the 'config' and 'binary' * files. */ enum { ENTRYPOINT_STACK_SIZE = 12*1024 }; Genode::Rpc_entrypoint _entrypoint; /** * ELF binary */ Genode::Rom_connection _binary_rom; Genode::Dataspace_capability _binary_rom_ds; /** * Private child configuration */ Init::Child_config _config; /** * Each child of init can act as a server */ Genode::Server _server; Genode::Child _child; Genode::Service_registry *_parent_services; Genode::Service_registry *_child_services; /** * Policy helpers */ Init::Child_policy_enforce_labeling _labeling_policy; Init::Child_policy_handle_cpu_priorities _priority_policy; Init::Child_policy_provide_rom_file _config_policy; Init::Child_policy_provide_rom_file _binary_policy; Init::Child_policy_redirect_rom_file _configfile_policy; Init::Child_policy_pd_args _pd_args_policy; public: Child(Genode::Xml_node start_node, Genode::Xml_node default_route_node, Name_registry *name_registry, long prio_levels_log2, Genode::Affinity::Space const &affinity_space, Genode::Service_registry *parent_services, Genode::Service_registry *child_services, Genode::Cap_session *cap_session) : _list_element(this), _start_node(start_node), _default_route_node(default_route_node), _name_registry(name_registry), _name(start_node, name_registry), _pd_args(start_node), _resources(start_node, _name.unique, prio_levels_log2, affinity_space), _entrypoint(cap_session, ENTRYPOINT_STACK_SIZE, _name.unique, false), _binary_rom(_name.file, _name.unique), _binary_rom_ds(_binary_rom.dataspace()), _config(_resources.ram.cap(), start_node), _server(_resources.ram.cap()), _child(_binary_rom_ds, _resources.ram.cap(), _resources.cpu.cap(), _resources.rm.cap(), &_entrypoint, this), _parent_services(parent_services), _child_services(child_services), _labeling_policy(_name.unique), _priority_policy(_resources.prio_levels_log2, _resources.priority), _config_policy("config", _config.dataspace(), &_entrypoint), _binary_policy("binary", _binary_rom_ds, &_entrypoint), _configfile_policy("config", _config.filename()), _pd_args_policy(&_pd_args) { using namespace Genode; if (_resources.ram_quota == 0) PWRN("no valid RAM resource for child \"%s\"", _name.unique); if (config_verbose) { Genode::printf("child \"%s\"\n", _name.unique); Genode::printf(" RAM quota: %zu\n", _resources.ram_quota); Genode::printf(" ELF binary: %s\n", _name.file); Genode::printf(" priority: %ld\n", _resources.priority); } /* * Determine services provided by the child */ try { Xml_node service_node = start_node.sub_node("provides").sub_node("service"); for (; ; service_node = service_node.next("service")) { char name[Genode::Service::MAX_NAME_LEN]; service_node.attribute("name").value(name, sizeof(name)); if (config_verbose) Genode::printf(" provides service %s\n", name); child_services->insert(new (_child.heap()) Routed_service(name, &_server)); } } catch (Xml_node::Nonexistent_sub_node) { } } virtual ~Child() { } /** * Return true if the child has the specified name */ bool has_name(const char *n) const { return !Genode::strcmp(name(), n); } Genode::Server *server() { return &_server; } /** * Start execution of child */ void start() { _entrypoint.activate(); } /**************************** ** Child-policy interface ** ****************************/ const char *name() const { return _name.unique; } Genode::Service *resolve_session_request(const char *service_name, const char *args) { Genode::Service *service = 0; /* check for config file request */ if ((service = _config_policy.resolve_session_request(service_name, args))) return service; /* check for binary file request */ if ((service = _binary_policy.resolve_session_request(service_name, args))) return service; try { Genode::Xml_node route_node = _default_route_node; try { route_node = _start_node.sub_node("route"); } catch (...) { } Genode::Xml_node service_node = route_node.sub_node(); for (; ; service_node = service_node.next()) { bool service_wildcard = service_node.has_type("any-service"); if (!service_node_matches(service_node, service_name)) continue; if (!service_node_args_condition_satisfied(service_node, args, name())) continue; Genode::Xml_node target = service_node.sub_node(); for (; ; target = target.next()) { if (target.has_type("parent")) { service = _parent_services->find(service_name); if (service) return service; if (!service_wildcard) { PWRN("%s: service lookup for \"%s\" at parent failed", name(), service_name); return 0; } } if (target.has_type("child")) { char server_name[Name::MAX_NAME_LEN]; server_name[0] = 0; target.attribute("name").value(server_name, sizeof(server_name)); Genode::Server *server = _name_registry->lookup_server(server_name); if (!server) PWRN("%s: invalid route to non-existing server \"%s\"", name(), server_name); service = _child_services->find(service_name, server); if (service) return service; if (!service_wildcard) { PWRN("%s: lookup to child service \"%s\" failed", name(), service_name); return 0; } } if (target.has_type("any-child")) { if (_child_services->is_ambiguous(service_name)) { PERR("%s: ambiguous routes to service \"%s\"", name(), service_name); return 0; } service = _child_services->find(service_name); if (service) return service; if (!service_wildcard) { PWRN("%s: lookup for service \"%s\" failed", name(), service_name); return 0; } } if (target.is_last()) break; } } } catch (...) { PWRN("%s: no route to service \"%s\"", name(), service_name); } return service; } void filter_session_args(const char *service, char *args, Genode::size_t args_len) { _labeling_policy. filter_session_args(service, args, args_len); _priority_policy. filter_session_args(service, args, args_len); _configfile_policy.filter_session_args(service, args, args_len); _pd_args_policy. filter_session_args(service, args, args_len); } Genode::Affinity filter_session_affinity(Genode::Affinity const &session_affinity) { using namespace Genode; /* check if no valid affinity space was specified */ if (session_affinity.space().total() == 0) return session_affinity; Affinity::Space const &session_space = session_affinity.space(); Affinity::Location const &session_location = session_affinity.location(); Affinity::Space const &child_space = _resources.affinity.space(); Affinity::Location const &child_location = _resources.affinity.location(); /* scale resolution of resulting space */ Affinity::Space space(child_space.multiply(session_space)); /* subordinate session affinity to child affinity subspace */ Affinity::Location location(child_location .multiply_position(session_space) .transpose(session_location.xpos(), session_location.ypos())); return Affinity(space, location); } bool announce_service(const char *service_name, Genode::Root_capability root, Genode::Allocator *alloc, Genode::Server *server) { if (config_verbose) Genode::printf("child \"%s\" announces service \"%s\"\n", name(), service_name); Genode::Service *s = _child_services->find(service_name, &_server); Routed_service *rs = dynamic_cast(s); if (!s || !rs) { PERR("%s: illegal announcement of service \"%s\"", name(), service_name); return false; } rs->announce(root); return true; } void resource_request(Genode::Parent::Resource_args const &args) { Genode::printf("child \"%s\" requests resources: %s\n", name(), args.string()); Genode::size_t const requested_ram_quota = Genode::Arg_string::find_arg(args.string(), "ram_quota") .ulong_value(0); if (avail_slack_ram_quota() < requested_ram_quota) { PERR("Cannot respond to resource request - out of memory"); return; } /* * XXX Synchronize quota transfers from/to env()->ram_session() * * If multiple children issue concurrent resource requests, the * value reported by 'avail_slack_ram_quota' may be out of date * when calling 'transfer_quota'. */ Genode::env()->ram_session()->transfer_quota(_resources.ram.cap(), requested_ram_quota); /* wake up child that was starved for resources */ _child.notify_resource_avail(); } Genode::Native_pd_args const *pd_args() const { return &_pd_args; } }; } #endif /* _INCLUDE__INIT__CHILD_H_ */