summaryrefslogtreecommitdiff
path: root/internal/media/util.go
blob: 4e47955ada490a22b694a9869758dc221f863660 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
// 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"

	"codeberg.org/gruf/go-bytesize"
	"codeberg.org/gruf/go-iotools"
	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
)

// file represents one file
// with the given flag and perms.
type file struct {
	abs  string
	flag int
	perm os.FileMode
}

// 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 {
		var (
			abs  = file.abs
			flag = file.flag
			perm = file.perm
		)

		// Allowed to open file
		// at absolute path.
		if name == file.abs {
			return os.OpenFile(abs, flag, perm)
		}

		// Check for other valid reads.
		thisDir, thisFile := path.Split(file.abs)

		// Allowed to read directory itself.
		if name == thisDir || name == "." {
			return os.OpenFile(thisDir, flag, perm)
		}

		// Allowed to read file
		// itself (at relative path).
		if name == thisFile {
			return os.OpenFile(abs, flag, perm)
		}
	}

	return nil, os.ErrPermission
}

// 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) {
	defer rc.Close()

	// Open new temporary file.
	tmp, err := os.CreateTemp(
		os.TempDir(),
		"gotosocial-*",
	)
	if err != nil {
		return "", err
	}
	defer tmp.Close()

	// 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...)
}