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Limit number of simultaneous file extractions to prevent hardlock

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Added helper extraction functions
chmod & chown is now set after a folder's extraction to prevent permission issues
This commit is contained in:
Caleb Gardner
2023-04-17 10:22:10 -05:00
parent 2ba4551fb9
commit d2c72f9464
5 changed files with 118 additions and 21 deletions
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.gitignore
+1
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@@ -1 +1,2 @@
testing
/go-unsquashfs
cmd/go-unsquashfs/main.go
+37
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@@ -0,0 +1,37 @@
package main
import (
"flag"
"fmt"
"os"
"time"
"github.com/CalebQ42/squashfs"
)
func main() {
verbose := flag.Bool("v", false, "Verbose")
ignore := flag.Bool("ip", false, "Ignore Permissions and extract all files/folders with 0755")
flag.Parse()
if len(flag.Args()) < 2 {
fmt.Println("Please provide a file name and extraction path")
os.Exit(0)
}
f, err := os.Open(flag.Arg(0))
if err != nil {
panic(err)
}
r, err := squashfs.NewReader(f)
if err != nil {
panic(err)
}
op := squashfs.DefaultOptions()
op.Verbose = *verbose
op.IgnorePerm = *ignore
n := time.Now()
err = r.ExtractWithOptions(flag.Arg(1), op)
if err != nil {
panic(err)
}
fmt.Println("Took:", time.Since(n))
}
internal/threadmanager/manager.go
+23
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@@ -0,0 +1,23 @@
package threadmanager
type Manager struct {
c chan int
}
func NewManager(maxRoutines int) *Manager {
m := &Manager{
c: make(chan int, maxRoutines),
}
for i := 0; i < maxRoutines; i++ {
m.c <- i
}
return m
}
func (m *Manager) Lock() int {
return <-m.c
}
func (m *Manager) Unlock(n int) {
m.c <- n
}
reader_file.go
+48 -18
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@@ -15,6 +15,7 @@ import (
"github.com/CalebQ42/squashfs/internal/data"
"github.com/CalebQ42/squashfs/internal/directory"
"github.com/CalebQ42/squashfs/internal/inode"
"github.com/CalebQ42/squashfs/internal/threadmanager"
)
// File represents a file inside a squashfs archive.
@@ -219,25 +220,48 @@ func (f File) GetSymlinkFile() *File {
// ExtractionOptions are available options on how to extract.
type ExtractionOptions struct {
manager *threadmanager.Manager
LogOutput io.Writer //Where error log should write.
DereferenceSymlink bool //Replace symlinks with the target file.
UnbreakSymlink bool //Try to make sure symlinks remain unbroken when extracted, without changing the symlink.
Verbose bool //Prints extra info to log on an error.
IgnorePerm bool //Ignore file's permissions and instead use FolderPerm.
FolderPerm fs.FileMode //Permission to use when making the root folder if it doesn't exist.
IgnorePerm bool //Ignore file's permissions and instead use Perm.
Perm fs.FileMode //Permission to use when IgnorePerm. Defaults to 0755.
notFirst bool
}
func DefaultOptions() *ExtractionOptions {
return &ExtractionOptions{
Perm: 0755,
}
}
// ExtractTo extracts the File to the given folder with the default options.
// If the File is a directory, it instead extracts the directory's contents to the folder.
func (f File) ExtractTo(folder string) error {
return f.realExtract(folder, &ExtractionOptions{})
return f.realExtract(folder, DefaultOptions())
}
// ExtractVerbose extracts the File to the folder with the Verbose option.
func (f File) ExtractVerbose(folder string) error {
op := DefaultOptions()
op.Verbose = true
return f.realExtract(folder, op)
}
// ExtractIgnorePermissions extracts the File to the folder with the IgnorePerm option.
func (f File) ExtractIgnorePermissions(folder string) error {
op := DefaultOptions()
op.IgnorePerm = true
return f.realExtract(folder, op)
}
// ExtractSymlink extracts the File to the folder with the DereferenceSymlink option.
// If the File is a directory, it instead extracts the directory's contents to the folder.
func (f File) ExtractSymlink(folder string) error {
return f.realExtract(folder, &ExtractionOptions{})
op := DefaultOptions()
op.DereferenceSymlink = true
return f.realExtract(folder, op)
}
// ExtractWithOptions extracts the File to the given folder with the given ExtrationOptions.
@@ -250,6 +274,9 @@ func (f File) ExtractWithOptions(folder string, op *ExtractionOptions) error {
}
func (f File) realExtract(folder string, op *ExtractionOptions) (err error) {
if op.manager == nil {
op.manager = threadmanager.NewManager(runtime.NumCPU())
}
extDir := folder + "/" + f.e.Name
if !op.notFirst {
op.notFirst = true
@@ -257,11 +284,7 @@ func (f File) realExtract(folder string, op *ExtractionOptions) (err error) {
extDir = folder
_, err = os.Open(folder)
if err != nil && os.IsNotExist(err) {
if op.IgnorePerm {
err = os.Mkdir(extDir, op.FolderPerm|(f.Mode()&fs.ModeType))
} else {
err = os.Mkdir(extDir, f.Mode())
}
err = os.Mkdir(extDir, op.Perm)
}
if err != nil {
if op.Verbose {
@@ -274,17 +297,19 @@ func (f File) realExtract(folder string, op *ExtractionOptions) (err error) {
switch {
case f.IsDir():
if folder != extDir && f.e.Name != "" {
if op.IgnorePerm {
err = os.Mkdir(extDir, op.FolderPerm|(f.Mode()&fs.ModeType))
} else {
err = os.Mkdir(extDir, f.Mode())
}
//First extract it with a permisive permission.
err = os.Mkdir(extDir, op.Perm)
if err != nil {
if op.Verbose {
log.Println("Error while making directory", extDir)
}
return
}
//Then set it to it's actual permissions once we're done with it
if !op.IgnorePerm {
defer os.Chmod(extDir, f.Mode())
defer os.Chown(extDir, int(f.r.ids[f.i.UidInd]), int(f.r.ids[f.i.GidInd]))
}
}
var filFS *FS
filFS, err = f.FS()
@@ -324,6 +349,8 @@ func (f File) realExtract(folder string, op *ExtractionOptions) (err error) {
//Then we extract the files.
for i = 0; i < len(files); i++ {
go func(index int) {
n := op.manager.Lock()
defer op.manager.Unlock(n)
subF, goErr := f.r.newFile(files[index], filFS)
if goErr != nil {
if op.Verbose {
@@ -368,9 +395,10 @@ func (f File) realExtract(folder string, op *ExtractionOptions) (err error) {
return err
}
if op.IgnorePerm {
os.Chmod(fil.Name(), op.FolderPerm|(f.Mode()&fs.ModeType))
os.Chmod(extDir, op.Perm|(f.Mode()&fs.ModeType))
} else {
os.Chmod(fil.Name(), f.Mode())
os.Chmod(extDir, f.Mode())
os.Chown(extDir, int(f.r.ids[f.i.UidInd]), int(f.r.ids[f.i.GidInd]))
}
case f.IsSymlink():
symPath := f.SymlinkPath()
@@ -420,9 +448,10 @@ func (f File) realExtract(folder string, op *ExtractionOptions) (err error) {
return err
}
if op.IgnorePerm {
os.Chmod(extDir, op.FolderPerm|(f.Mode()&fs.ModeType))
os.Chmod(extDir, op.Perm|(f.Mode()&fs.ModeType))
} else {
os.Chmod(extDir, f.Mode())
os.Chown(extDir, int(f.r.ids[f.i.UidInd]), int(f.r.ids[f.i.GidInd]))
}
case f.isDeviceOrFifo():
if runtime.GOOS == "windows" {
@@ -469,9 +498,10 @@ func (f File) realExtract(folder string, op *ExtractionOptions) (err error) {
return err
}
if op.IgnorePerm {
os.Chmod(extDir, op.FolderPerm|(f.Mode()&fs.ModeType))
os.Chmod(extDir, op.Perm|(f.Mode()&fs.ModeType))
} else {
os.Chmod(extDir, f.Mode())
os.Chown(extDir, int(f.r.ids[f.i.UidInd]), int(f.r.ids[f.i.GidInd]))
}
case f.e.Type == inode.Sock:
if op.Verbose {
squashfs_test.go
+8 -2
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@@ -18,7 +18,7 @@ import (
)
const (
squashfsURL = "https://darkstorm.tech/LinuxPATest.sfs"
squashfsURL = "https://darkstorm.tech/files/LinuxPATest.sfs"
squashfsName = "LinuxPATest.sfs"
filePath = "PortableApps/Notepad++Portable/App/DefaultData/Config/contextMenu.xml"
@@ -122,7 +122,13 @@ func TestExtractQuick(t *testing.T) {
if err != nil {
t.Fatal(err)
}
err = rdr.ExtractWithOptions(libPath, &squashfs.ExtractionOptions{Verbose: true})
os.RemoveAll(filepath.Join(tmpDir, "testLog.txt"))
logFil, _ := os.Create(filepath.Join(tmpDir, "testLog.txt"))
op := squashfs.DefaultOptions()
op.Verbose = true
op.IgnorePerm = true
op.LogOutput = logFil
err = rdr.ExtractWithOptions(libPath, op)
if err != nil {
t.Fatal(err)
}