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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package media
import (
"errors"
"fmt"
"io"
"io/fs"
"os"
"path"
"code.superseriousbusiness.org/gotosocial/internal/gtserror"
"codeberg.org/gruf/go-bytesize"
"codeberg.org/gruf/go-iotools"
)
// media processing tmpdir.
var tmpdir = os.TempDir()
// file represents one file
// with the given flag and perms.
type file struct {
abs string // absolute file path, including root
dir string // containing directory of abs
rel string // relative to root, i.e. trim_prefix(abs, dir)
flag int
perm os.FileMode
}
// allowRead returns a new file{} for filepath permitted only to read.
func allowRead(filepath string) file {
return newFile(filepath, os.O_RDONLY, 0)
}
// allowCreate returns a new file{} for filepath permitted to read / write / create.
func allowCreate(filepath string) file {
return newFile(filepath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
}
// newFile returns a new instance of file{} for given path and open args.
func newFile(filepath string, flag int, perms os.FileMode) file {
dir, rel := path.Split(filepath)
return file{
abs: filepath,
rel: rel,
dir: dir,
flag: flag,
perm: perms,
}
}
// allowFiles implements fs.FS to allow
// access to a specified slice of files.
type allowFiles []file
// Open implements fs.FS.
func (af allowFiles) Open(name string) (fs.File, error) {
for _, file := range af {
switch name {
// Allowed to open file
// at absolute path, or
// relative as ffmpeg likes.
case file.abs, file.rel:
return os.OpenFile(file.abs, file.flag, file.perm)
// Ffmpeg likes to read containing
// dir as '.'. Allow RO access here.
case ".":
return openRead(file.dir)
}
}
return nil, os.ErrPermission
}
// openRead opens the existing file at path for reads only.
func openRead(path string) (*os.File, error) {
return os.OpenFile(path, os.O_RDONLY, 0)
}
// openWrite opens the (new!) file at path for read / writes.
func openWrite(path string) (*os.File, error) {
return os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
}
// getExtension splits file extension from path.
func getExtension(path string) string {
for i := len(path) - 1; i >= 0 && path[i] != '/'; i-- {
if path[i] == '.' {
return path[i+1:]
}
}
return ""
}
// drainToTmp drains data from given reader into a new temp file
// and closes it, returning the path of the resulting temp file.
//
// Note that this function specifically makes attempts to unwrap the
// io.ReadCloser as much as it can to underlying type, to maximise
// chance that Linux's sendfile syscall can be utilised for optimal
// draining of data source to temporary file storage.
func drainToTmp(rc io.ReadCloser) (string, error) {
var tmp *os.File
var err error
// Close handles
// on func return.
defer func() {
tmp.Close()
rc.Close()
}()
// Open new temporary file.
tmp, err = os.CreateTemp(
tmpdir,
"gotosocial-*",
)
if err != nil {
return "", err
}
// Extract file path.
path := tmp.Name()
// Limited reader (if any).
var lr *io.LimitedReader
var limit int64
// Reader type to use
// for draining to tmp.
rd := (io.Reader)(rc)
// Check if reader is actually wrapped,
// (as our http client wraps close func).
rct, ok := rc.(*iotools.ReadCloserType)
if ok {
// Get unwrapped.
rd = rct.Reader
// Extract limited reader if wrapped.
lr, limit = iotools.GetReaderLimit(rd)
}
// Drain reader into tmp.
_, err = tmp.ReadFrom(rd)
if err != nil {
return path, err
}
// Check to see if limit was reached,
// (produces more useful error messages).
if lr != nil && lr.N <= 0 {
err := fmt.Errorf("reached read limit %s", bytesize.Size(limit)) // #nosec G115 -- Just logging
return path, gtserror.SetLimitReached(err)
}
return path, nil
}
// remove only removes paths if not-empty.
func remove(paths ...string) error {
var errs []error
for _, path := range paths {
if path != "" {
if err := os.Remove(path); err != nil {
errs = append(errs, fmt.Errorf("error removing %s: %w", path, err))
}
}
}
return errors.Join(errs...)
}
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