[srv.init] Rework init to use module iterator

Init now uses a module iterator that facilitates filtering on module
type.

src/user/srv.init/main.cpp

@@ -1,6 +1,13 @@
+#include <stdio.h>
 #include "j6/syscalls.h"
+#include "init_args.h"
+
 #include "modules.h"
 
+using kernel::init::module;
+using kernel::init::module_type;
+using kernel::init::module_program;
+
 extern "C" {
     int main(int, const char **);
 }
@@ -14,7 +21,15 @@ int
 main(int argc, const char **argv)
 {
     j6_system_log("srv.init starting");
-    modules::load_all(_arg_modules_phys);
+
+    modules mods = modules::load_modules(_arg_modules_phys, handle_system, handle_self);
+
+    char message[100];
+    for (auto &mod : mods.of_type(module_type::program)) {
+        auto &prog = static_cast<const module_program&>(mod);
+        sprintf(message, "  program module '%s' at %lx", prog.filename, prog.base_address);
+        j6_system_log(message);
+    }
 
     return 0;
 }

src/user/srv.init/modules.cpp

@@ -3,68 +3,80 @@
 
 #include "j6/errors.h"
 #include "j6/syscalls.h"
-#include "init_args.h"
-#include "pointer_manipulation.h"
 
 #include "modules.h"
 
-using namespace kernel::init;
-
-extern j6_handle_t handle_self;
-extern j6_handle_t handle_system;
-
-namespace modules {
+using module = kernel::init::module;
+using modules_page = kernel::init::modules_page;
 
 static const modules_page *
-load_page(uintptr_t address)
+get_page(const module *mod)
+{
+    return reinterpret_cast<const modules_page*>(
+        reinterpret_cast<uintptr_t>(mod) & ~0xfffull);
+}
+
+const module *
+module_iterator::operator++()
+{
+    do {
+        m_mod = offset_ptr<module>(m_mod, m_mod->mod_length);
+
+        if (m_mod->mod_type == type::none) {
+            // We've reached the end of a page, see if there's another
+            const modules_page *page = get_page(m_mod);
+            if (!page->next) {
+                m_mod = nullptr;
+                break;
+            }
+
+            m_mod = page->modules;
+        }
+    }
+    while (m_type != type::none && m_type != m_mod->mod_type);
+
+    return m_mod;
+}
+
+const module *
+module_iterator::operator++(int)
+{
+    const module *tmp = m_mod;
+    operator++();
+    return tmp;
+}
+
+const modules_page *
+load_page(uintptr_t address, j6_handle_t system, j6_handle_t self)
 {
     j6_handle_t mods_vma = j6_handle_invalid;
-    j6_status_t s = j6_system_map_phys(handle_system, &mods_vma, address, 0x1000, 0);
+    j6_status_t s = j6_system_map_phys(system, &mods_vma, address, 0x1000, 0);
     if (s != j6_status_ok)
         exit(s);
 
-    s = j6_vma_map(mods_vma, handle_self, address);
+    s = j6_vma_map(mods_vma, self, address);
     if (s != j6_status_ok)
         exit(s);
 
-    return reinterpret_cast<modules_page*>(address);
+    return reinterpret_cast<const modules_page*>(address);
 }
 
-void
-load_all(uintptr_t address)
+modules
+modules::load_modules(uintptr_t address, j6_handle_t system, j6_handle_t self)
 {
-    module_framebuffer const *framebuffer = nullptr;
-
+    const module *first = nullptr;
     while (address) {
-        const modules_page *page = load_page(address);
+        const modules_page *page = load_page(address, system, self);
 
         char message[100];
-        sprintf(message, "srv.init loading %d modules from page at 0x%lx", page->count, address);
+        sprintf(message, "srv.init found %d modules from page at 0x%lx", page->count, address);
         j6_system_log(message);
 
-        module *mod = page->modules;
-        size_t count = page->count;
-        while (count--) {
-            switch (mod->mod_type) {
-                case module_type::framebuffer:
-                    framebuffer = reinterpret_cast<const module_framebuffer*>(mod);
-                    break;
-
-                case module_type::program:
-                    if (mod->mod_flags == module_flags::no_load)
-                        j6_system_log("Loaded program module");
-                    else
-                        j6_system_log("Non-loaded program module");
-                    break;
-
-                default:
-                    j6_system_log("Unknown module");
-            }
-            mod = offset_ptr<module>(mod, mod->mod_length);
-        }
-
+        if (!first)
+            first = page->modules;
         address = page->next;
     }
+
+    return modules {first};
 }
 
-} // namespace modules

src/user/srv.init/modules.h

@@ -2,10 +2,61 @@
 /// \file modules.h
 /// Routines for loading initial argument modules
 
-namespace modules {
+#include "j6/types.h"
+#include "init_args.h"
+#include "pointer_manipulation.h"
 
-/// Load all modules
-/// \arg address  The physical address of the first page of modules
-void load_all(uintptr_t address);
 
-} // namespace modules
+class module_iterator
+{
+public:
+    using type = kernel::init::module_type;
+    using module = kernel::init::module;
+
+    module_iterator(const module *m, type t = type::none) :
+        m_mod {m}, m_type {t} {}
+
+    const module * operator++();
+    const module * operator++(int);
+
+    bool operator==(const module* m) const { return m == m_mod; }
+    bool operator!=(const module* m) const { return m != m_mod; }
+    bool operator==(const module_iterator &i) const { return i.m_mod == m_mod; }
+    bool operator!=(const module_iterator &i) const { return i.m_mod != m_mod; }
+
+    const module & operator*() const { return *m_mod; }
+    operator const module & () const { return *m_mod; }
+    const module * operator->() const { return m_mod; }
+
+    // Allow iterators to be used in for(:) statments
+    module_iterator & begin() { return *this; }
+    module_iterator end() const { return nullptr; }
+
+private:
+    module const * m_mod;
+    type m_type;
+};
+
+class modules
+{
+public:
+    using type = kernel::init::module_type;
+    using iterator = module_iterator;
+
+    static modules load_modules(
+        uintptr_t address,
+        j6_handle_t system,
+        j6_handle_t self);
+
+    iterator of_type(type t) const { return iterator {m_root, t}; }
+
+    iterator begin() const { return iterator {m_root}; }
+    iterator end() const { return nullptr; }
+
+private:
+    using module = kernel::init::module;
+
+    modules(const module* root) : m_root {root} {}
+
+    const module *m_root;
+};