feature (drivers): implemented an infrastructure to link drivers into the kernel

inc/drivers/builtin/elf/relocation.h

@@ -31,6 +31,7 @@ typedef struct {
     int64_t     addend;
 } elf_relocation_a_T;
 
-void elf_relocate(elf_executable_T* executable, uint8_t* buffer, void* address);
+//void elf_relocate       (elf_executable_T* executable, uint8_t* buffer, void* address);
+bool elf_relocate_driver(elf_executable_T* executable, uint8_t* buffer, void* load_address);
 
 #endif //NOXOS_RELOCATION_H

inc/drivers/builtin/elf/section.h

@@ -16,6 +16,9 @@ typedef enum {
     ELF_SECTION_DYNAMIC,
     ELF_SECTION_NOTE,
     ELF_SECTION_NOBITS,
+    ELF_SECTION_REL,
+    ELF_SECTION_SHLIB,
+    ELF_SECTION_DYNAMIC_SYMBOL_TABLE,
 
     ELF_SECTION_ENUM_END
 } elf_section_type_E;

src/boot/kmain.c

@@ -88,9 +88,14 @@ void kmain(boot_info_T boot_info) {
 //
 //    syscall_perform(SYSCALL_PROCESS_SIGNAL, pid, PROCESS_SIGNAL_START, 0, 0);
 
-    vfs_node_T* node = vfs_resolve_path(&g_root_fs, "/initrd/test_driver.nxkm");
+    vfs_node_T* node = vfs_resolve_path(&g_root_fs, "/initrd/test.nxkm");
     elf_executable_T* executable = elf_executable_create(node->cache->buffer);
-    driver_register(executable, node->cache->buffer);
+    driver_T* drv = driver_register(executable, node->cache->buffer);
+
+    void* entry = drv->base + symbol_resolve_from_name(executable->symbols, executable->num_symbols, "_start")->address;
+
+    void (*drv_test)() = entry;
+    drv_test();
 
     CORE_HALT_FOREVER
 }

src/drivers/api.c

@@ -0,0 +1,7 @@
+// This file is part of noxos and licensed under the MIT open source license
+
+#include <utils/logger.h>
+
+void nx_drv_init() {
+    DEBUG("hello from the driver api");
+}

src/drivers/builtin/elf/relocation.c

@@ -1,26 +1,106 @@
 // This file is part of noxos and licensed under the MIT open source license
 
 #include <drivers/builtin/elf/relocation.h>
+#include <drivers/builtin/elf/dynamic.h>
+#include <drivers/builtin/elf/symbol.h>
 #include <utils/logger.h>
+#include <utils/memory.h>
+#include <proc/scheduler.h>
 
-void elf_relocate(elf_executable_T* executable, uint8_t* buffer, void* address) {
+//void elf_relocate(elf_executable_T* executable, uint8_t* buffer, void* address) {
+//    elf_section_T* sections        = (elf_section_T*)&buffer[executable->header.offset_section_header];
+//    elf_section_T* section_dynamic = NULL;
+//    for (uint32_t i = 0; i < executable->header.num_section_header_entries; i++) {
+//        if (sections[i].type != ELF_SECTION_DYNAMIC) continue;
+//        section_dynamic = &sections[i];
+//        DEBUG("Found DYNAMIC section %d", i);
+//        break;
+//    }
+//    if (section_dynamic == NULL) {
+//        log(LOG_ERROR, "Failed to relocate ELF executable (no .dynamic section found)");
+//        return;
+//    }
+//    uint32_t       num_dynamic_entries  = section_dynamic->length / section_dynamic->entry_size;
+//    elf_dynamic_T*     dynamic_entries  = (elf_dynamic_T*)&buffer[section_dynamic->offset];
+//    uint32_t       num_needed_libraries = 0;
+//
+//    for (int i = 0; i < num_dynamic_entries; i++) {
+//        switch (dynamic_entries[i].tag) {
+//            case ELF_DYNAMIC_TAG_NEEDED: {
+//                num_needed_libraries++;
+//                break;
+//            }
+//        }
+//    }
+//
+//    log(LOG_ERROR, "Failed to relocate executable (not implemented)");
+//
+//}
+
+bool elf_relocate_driver(elf_executable_T* executable, uint8_t* buffer, void* load_address) {
     elf_section_T* sections        = (elf_section_T*)&buffer[executable->header.offset_section_header];
+    string_t       section_names   = (string_t)&buffer[sections[executable->header.string_section_index].offset];
     elf_section_T* section_dynamic = NULL;
+    elf_section_T* section_dynstr  = NULL;
+    elf_section_T* section_dynsym  = NULL;
+
     for (uint32_t i = 0; i < executable->header.num_section_header_entries; i++) {
-        if (sections[i].type != ELF_SECTION_DYNAMIC) continue;
+        switch (sections[i].type) {
+            case ELF_SECTION_DYNAMIC: {
                 section_dynamic = &sections[i];
-        DEBUG("Found DYNAMIC section %d", i);
                 break;
             }
+            case ELF_SECTION_STRING_TABLE: {
+                if (!string_compare(".dynstr", &section_names[sections[i].name_offset])) break;
+                section_dynstr = &sections[i];
+                break;
+            }
+            case ELF_SECTION_DYNAMIC_SYMBOL_TABLE: {
+                section_dynsym = &sections[i];
+                break;
+            }
+        }
+    }
     if (section_dynamic == NULL) {
-        log(LOG_ERROR, "Failed to relocate ELF executable (no .dynamic section found)");
+        log(LOG_ERROR, "Failed to relocate driver executable (no .dynamic section found)");
-        return;
+        return false;
+    }
+    if (section_dynstr == NULL) {
+        log(LOG_ERROR, "Failed to relocate driver executable (no .dynstr section found)");
+        return false;
+    }
+    if (section_dynsym == NULL) {
+        log(LOG_ERROR, "Failed to relocate driver executable (no .dynsym section found)");
+        return false;
     }
 
-//    elf_section_T* section_rela = ;
+    for (uint32_t i = 0; i < executable->header.num_section_header_entries; i++) {
-//
+        if (sections[i].type != ELF_SECTION_RELOCATION_A) continue;
-//    uint32_t       num_relocations = sections[i].length / sections[i].entry_size;
-//    elf_section_T* related_section = &sections[sections[i].info];
 
-//    DEBUG("Found RELA section -> relocations: %d  section: 0x%x", num_relocations, related_section);
+        symbol_T*     symbols = scheduler_get_process(PROCESS_KERNEL)->executable->symbols;
+        uint64_t  num_symbols = scheduler_get_process(PROCESS_KERNEL)->executable->num_symbols;
+
+        uint32_t num_relocations = sections[i].length / sections[i].entry_size;
+        for (int j = 0; j < num_relocations; j++) {
+            elf_relocation_a_T*   relocation        = &((elf_relocation_a_T*)&buffer[sections[i].offset])[j];
+            uint64_t*             relocation_offset = (uint64_t*)&((uint8_t*)load_address)[relocation->offset];
+            elf_relocation_type_E relocation_type   = ELF_RELOCATION_TYPE(relocation->info);
+            elf_symbol_T*         drv_symbol        = &((elf_symbol_T*)&buffer[section_dynsym->offset])[ELF_RELOCATION_SYMBOL(relocation->info)];
+            string_t              drv_symbol_name   = (string_t)&buffer[section_dynstr->offset + drv_symbol->name_offset];
+            symbol_T*             k_symbol          = symbol_resolve_from_name(symbols, num_symbols, drv_symbol_name);
+            if (k_symbol == NULL) {
+                log(LOG_ERROR, "Failed to relocate driver (symbol '%s' not found in kernel)", drv_symbol_name);
+                return false;
+            }
+
+            switch (relocation_type) {
+                case ELF_REL_JUMP_SLOT: {
+                    *relocation_offset = k_symbol->address;
+                    break;
+                }
+            }
+        }
+    }
+
+    return true;
 }

src/drivers/builtin/elf/section.c

@@ -12,6 +12,9 @@ string_t g_elf_section_type_strings[ELF_SECTION_ENUM_END+1] = {
         "Dynamic Linker Info",
         "Note",
         "No Bits",
+        "Relocation",
+        "Unspecified Semantics (Not ABI Conform)",
+        "Symbol Table (Dynamic)",
 
         "Unknown"
 };

src/drivers/driver.c

@@ -74,9 +74,15 @@ driver_T* driver_register(elf_executable_T* executable, uint8_t* buffer) {
 
 
     elf_mappings_apply(executable->mappings, executable->num_mappings, buffer, driver->base, g_kernel_page_map);
-    elf_relocate(executable, buffer, driver->base);
+    bool status = elf_relocate_driver(executable, buffer, driver->base);
-
+    if (!status) {
+        bitmap_set(&chunk->drivers_bitmap, driver->id % DRIVER_MANAGER_CHUNK_SIZE, false);
+        chunk->free_slots += 1;
         return NULL;
+    }
+
+
+    return driver;
 }
 
 void driver_init(driver_T* driver, driver_config_header_T* conf) {