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Init: support for aliases for child names

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Fixes #1373
This commit is contained in:
Norman Feske 2015-01-16 21:43:20 +01:00 committed by Christian Helmuth
parent a0abb093ed
commit 363fd6065d
1 changed files with 201 additions and 71 deletions
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272
repos/os/src/init/main.cc
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@ -92,76 +92,188 @@ inline void determine_parent_services(Genode::Service_registry *services)
** Child registry **
********************/
namespace Init { struct Alias; }
/**
* Representation of an alias for a child
*/
struct Init::Alias : Genode::List<Alias>::Element
{
typedef Genode::String<128> Name;
typedef Genode::String<128> Child;
Name name;
Child child;
/**
* Exception types
*/
class Name_is_missing { };
class Child_is_missing { };
/**
* Utility to read a string attribute from an XML node
*
* \param STR string type
* \param EXC exception type raised if attribute is not present
*
* \param node XML node
* \param attr_name name of attribute to read
*/
template <typename STR, typename EXC>
static STR _read_string_attr(Genode::Xml_node node, char const *attr_name)
{
char buf[STR::size()];
if (!node.has_attribute(attr_name))
throw EXC();
node.attribute(attr_name).value(buf, sizeof(buf));
return STR(buf);
}
/**
* Constructor
*
* \throw Name_is_missing
* \throw Child_is_missing
*/
Alias(Genode::Xml_node alias)
:
name (_read_string_attr<Name, Name_is_missing> (alias, "name")),
child(_read_string_attr<Name, Child_is_missing>(alias, "child"))
{ }
};
namespace Init {
typedef Genode::List<Genode::List_element<Child> > Child_list;
class Child_registry : public Name_registry, Child_list
{
public:
/**
* Register child
*/
void insert(Child *child)
{
Child_list::insert(&child->_list_element);
}
/**
* Unregister child
*/
void remove(Child *child)
{
Child_list::remove(&child->_list_element);
}
/**
* Start execution of all children
*/
void start()
{
Genode::List_element<Child> *curr = first();
for (; curr; curr = curr->next())
curr->object()->start();
}
/**
* Return any of the registered children, or 0 if no child exists
*/
Child *any()
{
return first() ? first()->object() : 0;
}
/*****************************
** Name-registry interface **
*****************************/
bool is_unique(const char *name) const
{
Genode::List_element<Child> const *curr = first();
for (; curr; curr = curr->next())
if (curr->object()->has_name(name))
return false;
return true;
}
Genode::Server *lookup_server(const char *name) const
{
Genode::List_element<Child> const *curr = first();
for (; curr; curr = curr->next())
if (curr->object()->has_name(name))
return curr->object()->server();
return 0;
}
};
struct Child_registry;
}
class Init::Child_registry : public Name_registry, Child_list
{
private:
List<Alias> _aliases;
public:
/**
* Exception type
*/
class Alias_name_is_not_unique { };
/**
* Register child
*/
void insert(Child *child)
{
Child_list::insert(&child->_list_element);
}
/**
* Unregister child
*/
void remove(Child *child)
{
Child_list::remove(&child->_list_element);
}
/**
* Register alias
*/
void insert_alias(Alias *alias)
{
if (!is_unique(alias->name.string())) {
PERR("Alias name %s is not unique", alias->name.string());
throw Alias_name_is_not_unique();
}
_aliases.insert(alias);
}
/**
* Unregister alias
*/
void remove_alias(Alias *alias)
{
_aliases.remove(alias);
}
/**
* Start execution of all children
*/
void start()
{
Genode::List_element<Child> *curr = first();
for (; curr; curr = curr->next())
curr->object()->start();
}
/**
* Return any of the registered children, or 0 if no child exists
*/
Child *any()
{
return first() ? first()->object() : 0;
}
/**
* Return any of the registered aliases, or 0 if no alias exists
*/
Alias *any_alias()
{
return _aliases.first() ? _aliases.first() : 0;
}
/*****************************
** Name-registry interface **
*****************************/
bool is_unique(const char *name) const
{
/* check for name clash with an existing child */
Genode::List_element<Child> const *curr = first();
for (; curr; curr = curr->next())
if (curr->object()->has_name(name))
return false;
/* check for name clash with an existing alias */
for (Alias const *a = _aliases.first(); a; a = a->next()) {
if (Alias::Name(name) == a->name)
return false;
}
return true;
}
Genode::Server *lookup_server(const char *name) const
{
/*
* Check if an alias with the specified name exists. If so,
* look up the server referred to by the alias.
*/
for (Alias const *a = _aliases.first(); a; a = a->next())
if (Alias::Name(name) == a->name)
name = a->child.string();
/* look up child with the name */
Genode::List_element<Child> const *curr = first();
for (; curr; curr = curr->next())
if (curr->object()->has_name(name))
return curr->object()->server();
return 0;
}
};
int main(int, char **)
{
using namespace Init;
@ -202,17 +314,29 @@ int main(int, char **)
config()->xml_node().sub_node("default-route"); }
catch (...) { }
/* create aliases */
config()->xml_node().for_each_sub_node("alias", [&] (Xml_node alias_node) {
try {
children.insert_alias(new (env()->heap()) Alias(alias_node));
}
catch (Alias::Name_is_missing) {
PWRN("Missing 'name' attribute in '<alias>' entry\n"); }
catch (Alias::Child_is_missing) {
PWRN("Missing 'child' attribute in '<alias>' entry\n"); }
});
/* create children */
try {
Xml_node start_node = config()->xml_node().sub_node("start");
for (;; start_node = start_node.next("start")) {
config()->xml_node().for_each_sub_node("start", [&] (Xml_node start_node) {
try {
children.insert(new (env()->heap())
Init::Child(start_node, default_route_node,
&children, read_prio_levels_log2(),
read_affinity_space(),
&parent_services, &child_services, &cap));
&children, read_prio_levels_log2(),
read_affinity_space(),
&parent_services, &child_services, &cap));
}
catch (Rom_connection::Rom_connection_failed) {
/*
@ -220,9 +344,7 @@ int main(int, char **)
* by the Rom_connection constructor.
*/
}
if (start_node.is_last("start")) break;
}
});
/* start children */
children.start();
@ -232,6 +354,7 @@ int main(int, char **)
catch (Xml_node::Invalid_syntax) {
PERR("No children to start"); }
catch (Init::Child::Child_name_is_not_unique) { }
catch (Init::Child_registry::Alias_name_is_not_unique) { }
/*
* Respond to config changes at runtime
@ -250,6 +373,13 @@ int main(int, char **)
destroy(env()->heap(), child);
}
/* remove all known aliases */
while (children.any_alias()) {
Init::Alias *alias = children.any_alias();
children.remove_alias(alias);
destroy(env()->heap(), alias);
}
/* reset knowledge about parent services */
parent_services.remove_all();