macho/macho-go/internal/wrapper/action/save_imports.go

package action

import (
	"sort"
	"strings"

	// log "github.com/sirupsen/logrus"

	. "ios-wrapper/internal/wrapper/ofile"
	"ios-wrapper/pkg/protomodel"
)

type saveImports struct {
	keepSymbols []string
}

func (action *saveImports) withMacho(mf *MachoFile) error {
	action.saveToInfo(mf)
	mc := mf.Context()
	if mc.Header().IsDylib() {
		mc.WriteInfoToData(mf.Info())
	}
	return nil
}

func (action *saveImports) saveToInfo(mf *MachoFile) error {
	// calculateHash := func(name string) uint32 {
	// 	var h uint32 = 0x811c9dc5
	// 	for _, s := range name {
	// 		h ^= uint32(s)
	// 		h *= 0x01000193
	// 	}
	// 	return h
	// }

	mc := mf.Context()
	// symbols_storage := []*protomodel.MachoInfo_AllImportedSymbols{}
	symbols_raw := mc.CollectBindSymbols()
	sort.Slice(symbols_raw, func(i, j int) bool {
		orderedByLibrary := symbols_raw[i].Dylib() < symbols_raw[j].Dylib()
		if symbols_raw[i].Dylib() == symbols_raw[j].Dylib() {
			orderedBySymbol := symbols_raw[i].Name() < symbols_raw[j].Name()
			return orderedBySymbol
		}
		return orderedByLibrary
	})

	libs := []string{}
	symbols := []string{}
	tables := []*protomodel.MachoInfo_LibraryImportedSymbols{}

	var current_table *protomodel.MachoInfo_LibraryImportedSymbols

	current_lib := ""
	current_symbol := ""

	current_lib_idx := -1
	current_symbol_idx := -1

	intlSymbols := []string{}
	for _, symbol := range symbols_raw {
		if symbol.Dylib() == "/usr/local/opt/gettext/lib/libintl.8.dylib" {
			intlSymbols = append(intlSymbols, symbol.Name())
		}
	}
	action.keepSymbols = append(action.keepSymbols, intlSymbols...)

	// now we expect everything is sorted and easier to build strings tables
	// this is not fully optimized, there can be repeated symbol name in different libraries
	for _, symbol := range symbols_raw {
		if !symbol.SafeForRemoval() {
			continue
		}

		skip := false
		for _, keep := range action.keepSymbols {
			name := keep
			lib := ""
			parts := strings.Split(keep, ",")
			if len(parts) == 2 {
				name = parts[0]
				lib = parts[1]
			}

			if symbol.Name() != name {
				continue
			}
			if lib == "" || lib == symbol.Dylib() {
				skip = true
				break
			}
		}

		if skip {
			continue
		}

		// 	dylib_hash := calculateHash(symbol.Dylib())
		seg := mc.Segments()[symbol.Segment()]

		var offset uint64

		if symbol.Address() >= seg.Vmaddr() {
			// this is virtual address
			offset = symbol.Address() - seg.Vmaddr()
		} else {
			// this is file address
			offset = symbol.Address() - seg.Fileoff()
		}

		if current_lib != symbol.Dylib() {
			current_lib_idx += len(current_lib) + 1
			current_lib = symbol.Dylib()
			libs = append(libs, symbol.Dylib())
			tables = append(tables, &protomodel.MachoInfo_LibraryImportedSymbols{
				LibIndex: uint32(current_lib_idx),
				Nsymbols: 0,
				Symbols:  []*protomodel.MachoInfo_SymbolTable{},
			})
			current_table = tables[len(tables)-1]
		}
		if current_symbol != symbol.Name() {
			current_symbol_idx += len(current_symbol) + 1
			current_symbol = symbol.Name()
			symbols = append(symbols, symbol.Name())
		}
		current_table.Nsymbols += 1
		current_table.Symbols = append(current_table.Symbols, &protomodel.MachoInfo_SymbolTable{
			SymbolIndex:  uint32(current_symbol_idx),
			SegmentIndex: symbol.Segment(),
			Offset:       uint32(offset),
		})
	}
	mf.Info().Symbols = &protomodel.MachoInfo_AllImportedSymbols{
		Libs:    libs,
		Symbols: symbols,
		Tables:  tables,
	}

	mf.Info().Main = mc.Main()

	selectors_list := []*protomodel.MachoInfo_Selector{}
	for _, sel := range mc.CollectSpecialSelectors() {
		selectors_list = append(selectors_list, &protomodel.MachoInfo_Selector{
			Idx:  uint32(sel.Idx()),
			Name: sel.Name(),
		})
	}
	mf.Info().SpecialSelectors = selectors_list

	return nil
}

func (action *saveImports) withFat(ff *FatFile) error {
	return defaultWithFat(action, ff)
}

func NewSaveImportsAction(keepSymbols []string) *saveImports {
	return &saveImports{
		keepSymbols,
	}
}