/
filesystem_linux.go
219 lines (186 loc) · 4.7 KB
/
filesystem_linux.go
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package pufferpanel
import (
"errors"
"golang.org/x/sys/unix"
"os"
"path/filepath"
"strings"
"syscall"
)
func (sfp *fileServer) OpenFile(path string, flags int, mode os.FileMode) (*os.File, error) {
path = prepPath(path)
if path == "" {
return os.Open(sfp.dir)
}
//if this is not a create request, nuke mode
if flags&os.O_CREATE == 0 {
mode = 0
}
var fd int
var err error
if UseOpenat2() {
//at this point, we are going to work on openat2
fd, err = unix.Openat2(getFd(sfp.root), path, &unix.OpenHow{
Flags: uint64(flags),
Mode: uint64(syscallMode(mode)),
Resolve: unix.RESOLVE_BENEATH,
})
if err != nil {
return nil, err
}
} else {
//because openat is not permitted, we will have to play a game...
parts := strings.Split(path, string(filepath.Separator))
//follow the chain, this is just directories we're going through
var rootFd = getFd(sfp.root)
var previousFd = rootFd
for _, v := range parts[:len(parts)-1] {
fd, err = unix.Openat(previousFd, v, unix.O_NOFOLLOW|unix.O_PATH, syscallMode(0))
if previousFd != rootFd {
_ = unix.Close(previousFd)
}
if err != nil {
return nil, err
}
previousFd = fd
}
//now.... we can open the file
fd, err = unix.Openat(previousFd, parts[len(parts)-1], unix.O_NOFOLLOW|flags, syscallMode(mode))
if previousFd != rootFd {
_ = unix.Close(previousFd)
}
if err != nil {
return nil, err
}
}
file := os.NewFile(uintptr(fd), filepath.Base(path))
return file, nil
}
func (sfp *fileServer) MkdirAll(path string, mode os.FileMode) error {
//this is going to be recursive...
path = prepPath(path)
//now for each one, we just need to make each path, and hope this works
//in theory, the mkdir will be safe enough
parts := strings.Split(path, string(filepath.Separator))
//if it was just mkdir root... we don't do anything
if len(parts) == 0 {
return nil
}
var err error
for i := range parts {
err = sfp.Mkdir(filepath.Join(parts[:i+1]...), mode)
if err != nil && !errors.Is(err, os.ErrExist) {
return err
}
}
return nil
}
func (sfp *fileServer) Rename(source, target string) error {
source = prepPath(source)
target = prepPath(target)
sourceParent := filepath.Dir(source)
targetParent := filepath.Dir(target)
sourceName := filepath.Base(source)
targetName := filepath.Base(target)
sourceFolder, err := sfp.OpenFile(sourceParent, os.O_RDONLY, 0755)
if err != nil {
return err
}
defer Close(sourceFolder)
targetFolder, err := sfp.OpenFile(targetParent, os.O_RDONLY, 0755)
if err != nil {
return err
}
defer Close(targetFolder)
err = unix.Renameat2(getFd(sourceFolder), sourceName, getFd(targetFolder), targetName, 0)
return err
}
func (sfp *fileServer) Mkdir(path string, mode os.FileMode) error {
path = prepPath(path)
parent := filepath.Dir(path)
f := filepath.Base(path)
if parent == "" {
return unix.Mkdirat(getFd(sfp.root), f, syscallMode(mode))
} else {
folder, err := sfp.OpenFile(parent, os.O_RDONLY, mode)
if err != nil {
return err
}
defer Close(folder)
return unix.Mkdirat(getFd(folder), f, syscallMode(mode))
}
}
func (sfp *fileServer) Remove(path string) error {
path = prepPath(path)
parent := filepath.Dir(path)
f := filepath.Base(path)
folder, err := sfp.OpenFile(parent, os.O_RDONLY, 0755)
if err != nil {
return err
}
defer Close(folder)
expected, err := sfp.OpenFile(path, os.O_RDONLY, 0644)
if err != nil {
return err
}
stat, err := expected.Stat()
Close(expected)
if stat.IsDir() {
return unix.Unlinkat(getFd(folder), f, unix.AT_REMOVEDIR)
} else {
return unix.Unlinkat(getFd(folder), f, 0)
}
}
func (sfp *fileServer) RemoveAll(path string) error {
path = prepPath(path)
folder, err := sfp.OpenFile(path, os.O_RDONLY, 0755)
if err != nil {
return err
}
defer Close(folder)
files, err := folder.ReadDir(0)
if err != nil {
return err
}
//go through all the files, and call our stuff to delete it
for _, v := range files {
if v.Type()&os.ModeSymlink == 0 && v.IsDir() {
//recursive call, so we need to go into this one and delete things
err = sfp.RemoveAll(filepath.Join(path, v.Name()))
if err != nil {
return err
}
} else {
err = unix.Unlinkat(getFd(folder), v.Name(), 0)
if err != nil {
return err
}
}
}
err = sfp.Remove(path)
return err
}
func syscallMode(i os.FileMode) (o uint32) {
o |= uint32(i.Perm())
if i&os.ModeSetuid != 0 {
o |= syscall.S_ISUID
}
if i&os.ModeSetgid != 0 {
o |= syscall.S_ISGID
}
if i&os.ModeSticky != 0 {
o |= syscall.S_ISVTX
}
return
}
func getFd(f *os.File) int {
return int(f.Fd())
}
func prepPath(path string) string {
path = filepath.Clean(path)
path = strings.TrimPrefix(path, "/")
if path == "." || path == "/" {
return ""
}
return path
}