From 8da159a30545221601e35bca3c0327de1e3109fe Mon Sep 17 00:00:00 2001
From: taichi-kotake <taichi.kotake@aktsk.jp>
Date: Fri, 5 Jun 2020 11:26:31 +0900
Subject: [PATCH] reduced memory consumption by reducing memory size to split

---
 cmd/cmd.go           |  9 +++++----
 pkg/memory/search.go | 13 +++++++------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/cmd/cmd.go b/cmd/cmd.go
index 0d983fb..a7591cf 100644
--- a/cmd/cmd.go
+++ b/cmd/cmd.go
@@ -54,11 +54,11 @@ func Plist() (string, error) {
 	current_path, _ := os.Getwd()
 	_, package_name := filepath.Split(current_path)
 	for cmd, pid := range pids {
-        if cmd == package_name {
+		if cmd == package_name {
 			fmt.Printf("Target PID has been set to %s.\n", pid)
 			return pid, nil
 		}
-    }
+	}
 
 	return "", nil
 }
@@ -104,10 +104,11 @@ func Attach(pid string) error {
 
 func Find(pid string, targetVal string, dataType string) ([]Found, error) {
 	founds := []Found{}
-	// search value in /proc/<pid>/mem
+	// parse /proc/<pid>/map, and get writable area
 	mapsPath := fmt.Sprintf("/proc/%s/maps", pid)
-	memPath := fmt.Sprintf("/proc/%s/mem", pid)
 	addrRanges, err := memory.GetWritableAddrRanges(mapsPath)
+	// search value in /proc/<pid>/mem
+	memPath := fmt.Sprintf("/proc/%s/mem", pid)
 	if err != nil {
 		return nil, err
 	}
diff --git a/pkg/memory/search.go b/pkg/memory/search.go
index 7c6f129..35d2617 100644
--- a/pkg/memory/search.go
+++ b/pkg/memory/search.go
@@ -13,7 +13,7 @@ import (
 	"github.com/aktsk/apk-medit/pkg/converter"
 )
 
-var splitSize = 0x50000000
+var splitSize = 0x5000000
 var bufferPool = sync.Pool{
 	New: func() interface{} {
 		return make([]byte, splitSize)
@@ -58,19 +58,19 @@ func GetWritableAddrRanges(mapsPath string) ([][2]int, error) {
 }
 
 type Err struct {
-    err error
+	err error
 }
 
 func (e *Err) Error() string {
-    return fmt.Sprint(e.err)
+	return fmt.Sprint(e.err)
 }
 
 type ParseErr struct {
-    *Err
+	*Err
 }
 
 type TooManyErr struct {
-    *Err
+	*Err
 }
 
 func FindDataInAddrRanges(memPath string, targetBytes []byte, addrRanges [][2]int) ([]int, error) {
@@ -87,6 +87,7 @@ func FindDataInAddrRanges(memPath string, targetBytes []byte, addrRanges [][2]in
 			fmt.Println(err)
 		}
 		for i := 0; i < (memSize/splitSize)+1; i++ {
+			// target memory is too big to read all of it, so split it and then search in memory
 			splitIndex := (i + 1) * splitSize
 			splittedBeginAddr := beginAddr + i*splitSize
 			splittedEndAddr := endAddr
@@ -97,7 +98,7 @@ func FindDataInAddrRanges(memPath string, targetBytes []byte, addrRanges [][2]in
 			ReadMemory(f, b, splittedBeginAddr, splittedEndAddr)
 			findDataInSplittedMemory(&b, targetBytes, searchLength, splittedBeginAddr, 0, &foundAddrs)
 			bufferPool.Put(b)
-			if len(foundAddrs) > 50000 {
+			if len(foundAddrs) > 500000 {
 				fmt.Println("Too many addresses with target data found...")
 				return foundAddrs, TooManyErr{&Err{errors.New("Error: Too many addresses")}}
 			}