Core: ELF support

CHANGES

@@ -1,4 +1,6 @@
 0.7.0: (Future)
+Features:
+ - ELF support
 Bugfixes:
  - GB Audio: Make audio unsigned with bias (fixes mgba.io/i/749)
 Misc:

CMakeLists.txt

@@ -16,6 +16,7 @@ set(USE_PNG ON CACHE BOOL "Whether or not to enable PNG support")
 set(USE_LIBZIP ON CACHE BOOL "Whether or not to enable LIBZIP support")
 set(USE_MAGICK ON CACHE BOOL "Whether or not to enable ImageMagick support")
 set(USE_SQLITE3 ON CACHE BOOL "Whether or not to enable SQLite3 support")
+set(USE_ELF ON CACHE BOOL "Whether or not to enable ELF support")
 set(M_CORE_GBA ON CACHE BOOL "Build Game Boy Advance core")
 set(M_CORE_GB ON CACHE BOOL "Build Game Boy core")
 set(USE_LZMA ON CACHE BOOL "Whether or not to enable 7-Zip support")
@@ -397,6 +398,7 @@ find_feature(USE_MAGICK "MagickWand")
 find_feature(USE_EPOXY "epoxy")
 find_feature(USE_CMOCKA "cmocka")
 find_feature(USE_SQLITE3 "sqlite3")
+find_feature(USE_ELF "libelf")
 find_feature(ENABLE_PYTHON "PythonLibs")
 
 # Features
@@ -602,6 +604,13 @@ if(USE_SQLITE3)
 	list(APPEND FEATURE_SRC "${CMAKE_CURRENT_SOURCE_DIR}/src/feature/sqlite3/no-intro.c")
 endif()
 
+if(USE_ELF)
+	list(APPEND FEATURES ELF)
+	include_directories(AFTER ${LIBELF_INCLUDE_DIRS})
+	list(APPEND DEPENDENCY_LIB ${LIBELF_LIBRARIES})
+	set(CPACK_DEBIAN_PACKAGE_DEPENDS "${CPACK_DEBIAN_PACKAGE_DEPENDS},libelfg0")
+endif()
+
 if(ENABLE_SCRIPTING)
 	list(APPEND ENABLES SCRIPTING)
 
@@ -935,6 +944,7 @@ if(NOT QUIET)
 	message(STATUS "	ZIP support: ${SUMMARY_ZIP}")
 	message(STATUS "	7-Zip support: ${USE_LZMA}")
 	message(STATUS "	SQLite3 game database: ${USE_SQLITE3}")
+	message(STATUS "	ELF loading support: ${USE_ELF}")
 	message(STATUS "	OpenGL support: ${SUMMARY_GL}")
 	message(STATUS "Frontends:")
 	message(STATUS "	Qt: ${BUILD_QT}")

README.md

@@ -142,6 +142,7 @@ mGBA has no hard dependencies, however, the following optional dependencies are
 - libzip or zlib: for loading ROMs stored in zip files.
 - ImageMagick: for GIF recording.
 - SQLite3: for game databases.
+- libelf: for ELF loading.
 
 SQLite3, libpng, and zlib are included with the emulator, so they do not need to be externally compiled first.
 

include/mgba-util/elf-read.h

@@ -0,0 +1,46 @@
+/* Copyright (c) 2013-2017 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef ELF_READ_H
+#define ELF_READ_H
+
+#include <mgba-util/common.h>
+
+CXX_GUARD_START
+
+#ifdef USE_ELF
+
+#include <libelf.h>
+#include <elf_repl.h>
+
+#include <mgba-util/vector.h>
+
+struct ELF;
+struct VFile;
+
+DECLARE_VECTOR(ELFProgramHeaders, Elf32_Phdr);
+DECLARE_VECTOR(ELFSectionHeaders, Elf32_Shdr);
+
+struct ELF* ELFOpen(struct VFile*);
+void ELFClose(struct ELF*);
+
+void* ELFBytes(struct ELF*, size_t* size);
+
+uint16_t ELFMachine(struct ELF*);
+uint32_t ELFEntry(struct ELF*);
+
+void ELFGetProgramHeaders(struct ELF*, struct ELFProgramHeaders*);
+
+size_t ELFFindSection(struct ELF*, const char* name);
+void ELFGetSectionHeaders(struct ELF*, struct ELFSectionHeaders*);
+Elf32_Shdr* ELFGetSectionHeader(struct ELF*, size_t index);
+
+const char* ELFGetString(struct ELF*, size_t section, size_t string);
+
+#endif
+
+CXX_GUARD_END
+
+#endif

include/mgba/core/core.h

@@ -189,6 +189,14 @@ void mCoreLoadForeignConfig(struct mCore* core, const struct mCoreConfig* config
 
 void mCoreSetRTC(struct mCore* core, struct mRTCSource* rtc);
 
+void* mCoreGetMemoryBlock(struct mCore* core, uint32_t start, size_t* size);
+
+#ifdef USE_ELF
+struct ELF;
+bool mCoreLoadELF(struct mCore* core, struct ELF* elf);
+void mCoreLoadELFSymbols(struct mDebuggerSymbols* symbols, struct ELF*);
+#endif
+
 CXX_GUARD_END
 
 #endif

include/mgba/internal/gba/gba.h

@@ -168,6 +168,7 @@ void GBALoadBIOS(struct GBA* gba, struct VFile* vf);
 void GBAApplyPatch(struct GBA* gba, struct Patch* patch);
 
 bool GBALoadMB(struct GBA* gba, struct VFile* vf);
+bool GBALoadNull(struct GBA* gba);
 
 bool GBAIsROM(struct VFile* vf);
 bool GBAIsMB(struct VFile* vf);

src/core/core.c

@@ -8,6 +8,11 @@
 #include <mgba/core/log.h>
 #include <mgba/core/serialize.h>
 #include <mgba-util/vfs.h>
+#include <mgba/internal/debugger/symbols.h>
+
+#ifdef USE_ELF
+#include <mgba-util/elf-read.h>
+#endif
 
 #ifdef M_CORE_GB
 #include <mgba/gb/core.h>
@@ -273,3 +278,67 @@ void mCoreSetRTC(struct mCore* core, struct mRTCSource* rtc) {
 	core->rtc.custom = rtc;
 	core->rtc.override = RTC_CUSTOM_START;
 }
+
+void* mCoreGetMemoryBlock(struct mCore* core, uint32_t start, size_t* size) {
+	const struct mCoreMemoryBlock* blocks;
+	size_t nBlocks = core->listMemoryBlocks(core, &blocks);
+	size_t i;
+	for (i = 0; i < nBlocks; ++i) {
+		if (!(blocks[i].flags & mCORE_MEMORY_MAPPED)) {
+			continue;
+		}
+		if (start < blocks[i].start) {
+			continue;
+		}
+		if (start >= blocks[i].start + blocks[i].size) {
+			continue;
+		}
+		uint8_t* out = core->getMemoryBlock(core, blocks[i].id, size);
+		out += start - blocks[i].start;
+		*size -= start - blocks[i].start;
+		return out;
+	}
+	return NULL;
+}
+
+#ifdef USE_ELF
+bool mCoreLoadELF(struct mCore* core, struct ELF* elf) {
+	struct ELFProgramHeaders ph;
+	ELFProgramHeadersInit(&ph, 0);
+	ELFGetProgramHeaders(elf, &ph);
+	size_t i;
+	for (i = 0; i < ELFProgramHeadersSize(&ph); ++i) {
+		size_t bsize, esize;
+		Elf32_Phdr* phdr = ELFProgramHeadersGetPointer(&ph, i);
+		void* block = mCoreGetMemoryBlock(core, phdr->p_paddr, &bsize);
+		char* bytes = ELFBytes(elf, &esize);
+		if (block && bsize >= phdr->p_filesz && esize >= phdr->p_filesz + phdr->p_offset) {
+			memcpy(block, &bytes[phdr->p_offset], phdr->p_filesz);
+		} else {
+			return false;
+		}
+	}
+	return true;
+}
+
+void mCoreLoadELFSymbols(struct mDebuggerSymbols* symbols, struct ELF* elf) {
+	size_t symIndex = ELFFindSection(elf, ".symtab");
+	size_t names = ELFFindSection(elf, ".strtab");
+	Elf32_Shdr* symHeader = ELFGetSectionHeader(elf, symIndex);
+	char* bytes = ELFBytes(elf, NULL);
+
+	Elf32_Sym* syms = (Elf32_Sym*) &bytes[symHeader->sh_offset];
+	size_t i;
+	for (i = 0; i * sizeof(*syms) < symHeader->sh_size; ++i) {
+		if (!syms[i].st_name || ELF32_ST_TYPE(syms[i].st_info) == STT_FILE) {
+			continue;
+		}
+		const char* name = ELFGetString(elf, names, syms[i].st_name);
+		if (name[0] == '$') {
+			continue;
+		}
+		mDebuggerSymbolAdd(symbols, name, syms[i].st_value, -1);
+	}
+}
+
+#endif

src/gba/core.c

@@ -8,6 +8,7 @@
 #include <mgba/core/core.h>
 #include <mgba/core/log.h>
 #include <mgba/internal/arm/debugger/debugger.h>
+#include <mgba/internal/debugger/symbols.h>
 #include <mgba/internal/gba/cheats.h>
 #include <mgba/internal/gba/gba.h>
 #include <mgba/internal/gba/io.h>
@@ -20,6 +21,9 @@
 #include <mgba/internal/gba/renderers/video-software.h>
 #include <mgba/internal/gba/savedata.h>
 #include <mgba/internal/gba/serialize.h>
+#ifdef USE_ELF
+#include <mgba-util/elf-read.h>
+#endif
 #include <mgba-util/memory.h>
 #include <mgba-util/patch.h>
 #include <mgba-util/vfs.h>
@@ -307,6 +311,15 @@ static void _GBACoreSetAVStream(struct mCore* core, struct mAVStream* stream) {
 }
 
 static bool _GBACoreLoadROM(struct mCore* core, struct VFile* vf) {
+#ifdef USE_ELF
+	struct ELF* elf = ELFOpen(vf);
+	if (elf) {
+		GBALoadNull(core->board);
+		bool success = mCoreLoadELF(core, elf);
+		ELFClose(elf);
+		return success;
+	}
+#endif
 	if (GBAIsMB(vf)) {
 		return GBALoadMB(core->board, vf);
 	}
@@ -696,7 +709,27 @@ static void _GBACoreDetachDebugger(struct mCore* core) {
 }
 
 static void _GBACoreLoadSymbols(struct mCore* core, struct VFile* vf) {
-	// TODO
+#ifdef USE_ELF
+	bool closeAfter = false;
+	core->symbolTable = mDebuggerSymbolTableCreate();
+#if !defined(MINIMAL_CORE) || MINIMAL_CORE < 2
+	if (!vf) {
+		closeAfter = true;
+		vf = mDirectorySetOpenSuffix(&core->dirs, core->dirs.base, ".elf", O_RDONLY);
+	}
+#endif
+	if (!vf) {
+		return;
+	}
+	struct ELF* elf = ELFOpen(vf);
+	if (elf) {
+		mCoreLoadELFSymbols(core->symbolTable, elf);
+		ELFClose(elf);
+	}
+	if (closeAfter) {
+		vf->close(vf);
+	}
+#endif
 }
 #endif
 

src/gba/gba.c

@@ -21,6 +21,10 @@
 #include <mgba-util/memory.h>
 #include <mgba-util/vfs.h>
 
+#ifdef USE_ELF
+#include <mgba-util/elf-read.h>
+#endif
+
 mLOG_DEFINE_CATEGORY(GBA, "GBA", "gba");
 mLOG_DEFINE_CATEGORY(GBA_DEBUG, "GBA Debug", "gba.debug");
 
@@ -203,6 +207,10 @@ void GBAReset(struct ARMCore* cpu) {
 
 	gba->debug = false;
 	memset(gba->debugString, 0, sizeof(gba->debugString));
+
+	if (!gba->romVf) {
+		GBASkipBIOS(gba);
+	}
 }
 
 void GBASkipBIOS(struct GBA* gba) {
@@ -288,6 +296,25 @@ void GBADetachDebugger(struct GBA* gba) {
 }
 #endif
 
+bool GBALoadNull(struct GBA* gba) {
+	GBAUnloadROM(gba);
+	gba->romVf = NULL;
+	gba->pristineRomSize = 0;
+	gba->memory.wram = anonymousMemoryMap(SIZE_WORKING_RAM);
+#ifndef FIXED_ROM_BUFFER
+	gba->memory.rom = anonymousMemoryMap(SIZE_CART0);
+#else
+	gba->memory.rom = romBuffer;
+#endif
+	gba->isPristine = false;
+	gba->yankedRomSize = 0;
+	gba->memory.romSize = SIZE_CART0;
+	gba->memory.romMask = SIZE_CART0 - 1;
+	gba->memory.mirroring = false;
+	gba->romCrc32 = 0;
+	return true;
+}
+
 bool GBALoadMB(struct GBA* gba, struct VFile* vf) {
 	GBAUnloadROM(gba);
 	gba->romVf = vf;
@@ -479,6 +506,17 @@ void GBADebug(struct GBA* gba, uint16_t flags) {
 }
 
 bool GBAIsROM(struct VFile* vf) {
+#ifdef USE_ELF
+	struct ELF* elf = ELFOpen(vf);
+	if (elf) {
+		uint32_t entry = ELFEntry(elf);
+		bool isGBA = true;
+		isGBA = isGBA && ELFMachine(elf) == EM_ARM;
+		isGBA = isGBA && (entry == BASE_CART0 || entry == BASE_WORKING_RAM);
+		ELFClose(elf);
+		return isGBA;
+	}
+#endif
 	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET, SEEK_SET) < 0) {
 		return false;
 	}
@@ -496,6 +534,14 @@ bool GBAIsMB(struct VFile* vf) {
 	if (!GBAIsROM(vf)) {
 		return false;
 	}
+#ifdef USE_ELF
+	struct ELF* elf = ELFOpen(vf);
+	if (elf) {
+		bool isMB = ELFEntry(elf) == BASE_WORKING_RAM;
+		ELFClose(elf);
+		return isMB;
+	}
+#endif
 	if (vf->size(vf) > SIZE_WORKING_RAM) {
 		return false;
 	}

src/gba/memory.c

@@ -80,6 +80,8 @@ void GBAMemoryInit(struct GBA* gba) {
 	gba->memory.biosPrefetch = 0;
 	gba->memory.mirroring = false;
 
+	gba->memory.iwram = anonymousMemoryMap(SIZE_WORKING_IRAM);
+
 	GBADMAInit(gba);
 	GBAVFameInit(&gba->memory.vfame);
 }
@@ -107,9 +109,8 @@ void GBAMemoryReset(struct GBA* gba) {
 	}
 
 	if (gba->memory.iwram) {
-		mappedMemoryFree(gba->memory.iwram, SIZE_WORKING_IRAM);
+		memset(gba->memory.iwram, 0, SIZE_WORKING_IRAM);
 	}
-	gba->memory.iwram = anonymousMemoryMap(SIZE_WORKING_IRAM);
 
 	memset(gba->memory.io, 0, sizeof(gba->memory.io));
 

src/util/elf-read.c

@@ -0,0 +1,125 @@
+/* Copyright (c) 2013-2017 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include <mgba-util/elf-read.h>
+
+#ifdef USE_ELF
+
+#include <mgba-util/vfs.h>
+
+DEFINE_VECTOR(ELFProgramHeaders, Elf32_Phdr);
+DEFINE_VECTOR(ELFSectionHeaders, Elf32_Shdr);
+
+static bool _elfInit = false;
+
+struct ELF {
+	Elf* e;
+	struct VFile* vf;
+	size_t size;
+	char* memory;
+};
+
+struct ELF* ELFOpen(struct VFile* vf) {
+	if (!_elfInit) {
+		_elfInit = elf_version(EV_CURRENT) != EV_NONE;
+		if (!_elfInit) {
+			return NULL;
+		}
+	}
+	if (!vf) {
+		return NULL;
+	}
+	size_t size = vf->size(vf);
+	char* memory = vf->map(vf, size, MAP_READ);
+	if (!memory) {
+		return NULL;
+	}
+
+	Elf* e = elf_memory(memory, size);
+	if (!e || elf_kind(e) != ELF_K_ELF) {
+		elf_end(e);
+		vf->unmap(vf, memory, size);
+		return false;
+	}
+	struct ELF* elf = malloc(sizeof(*elf));
+	elf->e = e;
+	elf->vf = vf;
+	elf->size = size;
+	elf->memory = memory;
+	return elf;
+}
+
+void ELFClose(struct ELF* elf) {
+	elf_end(elf->e);
+	elf->vf->unmap(elf->vf, elf->memory, elf->size);
+	free(elf);
+}
+
+void* ELFBytes(struct ELF* elf, size_t* size) {
+	if (size) {
+		*size = elf->size;
+	}
+	return elf->memory;
+}
+
+uint16_t ELFMachine(struct ELF* elf) {
+	Elf32_Ehdr* hdr = elf32_getehdr(elf->e);
+	if (!hdr) {
+		return 0;
+	}
+	return hdr->e_machine;
+}
+
+uint32_t ELFEntry(struct ELF* elf) {
+	Elf32_Ehdr* hdr = elf32_getehdr(elf->e);
+	if (!hdr) {
+		return 0;
+	}
+	return hdr->e_entry;
+}
+
+void ELFGetProgramHeaders(struct ELF* elf, struct ELFProgramHeaders* ph) {
+	ELFProgramHeadersClear(ph);
+	Elf32_Ehdr* hdr = elf32_getehdr(elf->e);
+	Elf32_Phdr* phdr = elf32_getphdr(elf->e);
+	ELFProgramHeadersResize(ph, hdr->e_phnum);
+	memcpy(ELFProgramHeadersGetPointer(ph, 0), phdr, sizeof(*phdr) * hdr->e_phnum);
+}
+
+void ELFGetSectionHeaders(struct ELF* elf, struct ELFSectionHeaders* sh) {
+	ELFSectionHeadersClear(sh);
+	Elf_Scn* section = elf_getscn(elf->e, 0);
+	do {
+		*ELFSectionHeadersAppend(sh) = *elf32_getshdr(section);
+	} while ((section = elf_nextscn(elf->e, section)));
+}
+
+Elf32_Shdr* ELFGetSectionHeader(struct ELF* elf, size_t index) {
+	Elf_Scn* section = elf_getscn(elf->e, index);
+	return elf32_getshdr(section);
+}
+
+size_t ELFFindSection(struct ELF* elf, const char* name) {
+	Elf32_Ehdr* hdr = elf32_getehdr(elf->e);
+	size_t shstrtab = hdr->e_shstrndx;
+	if (strcmp(name, ".shstrtab") == 0) {
+		return shstrtab;
+	}
+	Elf_Scn* section = NULL;
+	while ((section = elf_nextscn(elf->e, section))) {
+		Elf32_Shdr* shdr = elf32_getshdr(section);
+		const char* sname = elf_strptr(elf->e, shstrtab, shdr->sh_name);
+		if (strcmp(sname, name) == 0) {
+			return elf_ndxscn(section);
+		}
+	}
+	return 0;
+}
+
+const char* ELFGetString(struct ELF* elf, size_t section, size_t string) {
+	return elf_strptr(elf->e, section, string);
+}
+
+#endif