1 files changed, 268 insertions, 0 deletions
diff --git a/src/tools/mac/upload_system_symbols/arch_reader.go b/src/tools/mac/upload_system_symbols/arch_reader.go
new file mode 100644
index 00000000..0468836e
--- /dev/null
+++ b/src/tools/mac/upload_system_symbols/arch_reader.go
@@ -0,0 +1,268 @@
+/* Copyright 2014, Google Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+ * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+ * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+package main
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"os"
+	"reflect"
+	"unsafe"
+)
+
+/*
+#include <mach-o/fat.h>
+#include <mach-o/loader.h>
+#include <string.h>
+
+#include "arch_constants.h"
+*/
+import "C"
+
+var (
+	ErrNotMachO        = errors.New("GetMachOImageInfo: file is not a supported Mach-O image")
+	ErrUnsupportedArch = errors.New("GetMachOImageInfo: unknown architecture detected")
+)
+
+const (
+	ArchI386   = "i386"
+	ArchX86_64 = "x86_64"
+)
+
+type MachOType int
+
+const (
+	MachODylib  MachOType = C.kMachHeaderFtypeDylib
+	MachOBundle           = C.kMachHeaderFtypeBundle
+	MachOExe              = C.kMachHeaderFtypeExe
+)
+
+type ImageInfo struct {
+	Type MachOType
+	Arch string
+}
+
+// GetMachOImageInfo will read the file at filepath and determine if it is
+// Mach-O. If it is, it will return a slice of ImageInfo that describe the
+// images in the file (may be more than one if it is a fat image).
+func GetMachOImageInfo(filepath string) ([]ImageInfo, error) {
+	f, err := os.Open(filepath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	// Read the magic number to determine the type of file this is.
+	var magic uint32
+	err = binary.Read(f, binary.LittleEndian, &magic)
+	if err != nil {
+		return nil, err
+	}
+
+	// Rewind the file since the magic number is a field in the header
+	// structs.
+	f.Seek(0, os.SEEK_SET)
+
+	switch magic {
+	case C.kMachHeaderMagic32:
+		return readThinHeader(f, C.kMachHeaderMagic32)
+	case C.kMachHeaderMagic64:
+		return readThinHeader(f, C.kMachHeaderMagic64)
+	case C.kMachHeaderCigamFat: // Fat header is big-endian but was read in little.
+		return readFatHeader(f)
+	}
+
+	return nil, ErrNotMachO
+}
+
+func readThinHeader(f *os.File, expectedMagic uint32) ([]ImageInfo, error) {
+	var (
+		magic, filetype uint32
+		cpu             C.cpu_type_t
+		err             error
+	)
+
+	if expectedMagic == C.kMachHeaderMagic32 {
+		magic, cpu, filetype, err = readThin32Header(f)
+	} else if expectedMagic == C.kMachHeaderMagic64 {
+		magic, cpu, filetype, err = readThin64Header(f)
+	} else {
+		panic(fmt.Sprintf("Unexpected magic %#x", magic))
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if magic != expectedMagic {
+		return nil, fmt.Errorf("readThinHeader: unexpected magic number %#x", magic)
+	}
+
+	arch := cpuTypeToArch(cpu)
+	if arch == "" {
+		return nil, ErrUnsupportedArch
+	}
+	return []ImageInfo{{MachOType(filetype), arch}}, nil
+}
+
+func readThin32Header(f *os.File) (uint32, C.cpu_type_t, uint32, error) {
+	var machHeader C.struct_mach_header
+	err := readStruct(f, binary.LittleEndian, unsafe.Pointer(&machHeader), C.struct_mach_header{})
+	if err != nil {
+		return 0, 0, 0, err
+	}
+	return uint32(machHeader.magic), machHeader.cputype, uint32(machHeader.filetype), nil
+}
+
+func readThin64Header(f *os.File) (uint32, C.cpu_type_t, uint32, error) {
+	var machHeader C.struct_mach_header_64
+	err := readStruct(f, binary.LittleEndian, unsafe.Pointer(&machHeader), C.struct_mach_header_64{})
+	if err != nil {
+		return 0, 0, 0, err
+	}
+	return uint32(machHeader.magic), machHeader.cputype, uint32(machHeader.filetype), nil
+}
+
+func readFatHeader(f *os.File) ([]ImageInfo, error) {
+	var fatHeader C.struct_fat_header
+	err := readStruct(f, binary.BigEndian, unsafe.Pointer(&fatHeader), C.struct_fat_header{})
+	if err != nil {
+		return nil, err
+	}
+
+	if fatHeader.magic != C.kMachHeaderMagicFat {
+		return nil, fmt.Errorf("readFatHeader: unexpected magic number %#x", fatHeader.magic)
+	}
+
+	// Read the fat_arch headers.
+	headers := make([]C.struct_fat_arch, fatHeader.nfat_arch)
+	for i := 0; i < int(fatHeader.nfat_arch); i++ {
+		var fatArch C.struct_fat_arch
+		err = readStruct(f, binary.BigEndian, unsafe.Pointer(&fatArch), C.struct_fat_arch{})
+		if err != nil {
+			return nil, fmt.Errorf("readFatHeader: %v", err)
+		}
+		headers[i] = fatArch
+	}
+
+	seenArches := make(map[string]int)
+
+	// Now go to each arch in the fat image and read its mach header.
+	infos := make([]ImageInfo, 0, len(headers))
+	for _, header := range headers {
+		f.Seek(int64(header.offset), os.SEEK_SET)
+
+		var thinarch []ImageInfo
+		var expectedArch string
+		switch header.cputype {
+		case C.kCPUType_i386:
+			thinarch, err = readThinHeader(f, C.kMachHeaderMagic32)
+			expectedArch = ArchI386
+		case C.kCPUType_x86_64:
+			thinarch, err = readThinHeader(f, C.kMachHeaderMagic64)
+			expectedArch = ArchX86_64
+		default:
+			err = ErrUnsupportedArch
+		}
+
+		if err != nil {
+			return nil, err
+		}
+		if thinarch[0].Arch != expectedArch {
+			return nil, fmt.Errorf("readFatHeader: expected arch %d, got %d", thinarch[0].Arch, expectedArch)
+		}
+
+		infos = append(infos, thinarch[0])
+		seenArches[thinarch[0].Arch]++
+	}
+
+	for arch, count := range seenArches {
+		if count != 1 {
+			return nil, fmt.Errorf("readFatHeader: duplicate arch %s detected", arch)
+		}
+	}
+
+	return infos, nil
+}
+
+// TODO(rsesek): Support more arches.
+func cpuTypeToArch(cpu C.cpu_type_t) string {
+	switch cpu {
+	case C.kCPUType_i386:
+		return ArchI386
+	case C.kCPUType_x86_64:
+		return ArchX86_64
+	default:
+		return ""
+	}
+}
+
+// readStruct is a incomplete version of binary.Read that uses unsafe pointers
+// to set values in unexported fields. From |f|, this will read the fields of
+// the |destType| template instance, in the specified byte |order|, and place
+// the resulting memory into |dest|.
+func readStruct(f *os.File, order binary.ByteOrder, dest unsafe.Pointer, destType interface{}) error {
+	rv := reflect.ValueOf(destType)
+	rt := rv.Type()
+	destPtr := uintptr(dest)
+
+	for i := 0; i < rv.NumField(); i++ {
+		field := rv.Field(i)
+		fieldType := rt.Field(i)
+
+		var vp unsafe.Pointer
+		var err error
+
+		switch field.Kind() {
+		case reflect.Int32:
+			var v int32
+			vp = unsafe.Pointer(&v)
+			err = binary.Read(f, order, &v)
+		case reflect.Uint32:
+			var v uint32
+			vp = unsafe.Pointer(&v)
+			err = binary.Read(f, order, &v)
+		default:
+			err = fmt.Errorf("readStruct: unsupported type %v", fieldType)
+		}
+
+		if err != nil {
+			return err
+		}
+
+		memcpy(destPtr+fieldType.Offset, vp, fieldType.Type.Size())
+	}
+	return nil
+}
+
+func memcpy(dest uintptr, value unsafe.Pointer, size uintptr) {
+	C.memcpy(unsafe.Pointer(dest), value, C.size_t(size))
+}