mirror of
https://github.com/go-gitea/gitea
synced 2024-11-17 23:54:25 +00:00
103 lines
3.6 KiB
Go
103 lines
3.6 KiB
Go
// Copyright 2020 The Gitea Authors. All rights reserved.
|
||
// Use of this source code is governed by a MIT-style
|
||
// license that can be found in the LICENSE file.
|
||
|
||
package util
|
||
|
||
import "strings"
|
||
|
||
// Bash has the definition of a metacharacter:
|
||
// * A character that, when unquoted, separates words.
|
||
// A metacharacter is one of: " \t\n|&;()<>"
|
||
//
|
||
// The following characters also have addition special meaning when unescaped:
|
||
// * ‘${[*?!"'`\’
|
||
//
|
||
// Double Quotes preserve the literal value of all characters with then quotes
|
||
// excepting: ‘$’, ‘`’, ‘\’, and, when history expansion is enabled, ‘!’.
|
||
// The backslash retains its special meaning only when followed by one of the
|
||
// following characters: ‘$’, ‘`’, ‘"’, ‘\’, or newline.
|
||
// Backslashes preceding characters without a special meaning are left
|
||
// unmodified. A double quote may be quoted within double quotes by preceding
|
||
// it with a backslash. If enabled, history expansion will be performed unless
|
||
// an ‘!’ appearing in double quotes is escaped using a backslash. The
|
||
// backslash preceding the ‘!’ is not removed.
|
||
//
|
||
// -> This means that `!\n` cannot be safely expressed in `"`.
|
||
//
|
||
// Looking at the man page for Dash and ash the situation is similar.
|
||
//
|
||
// Now zsh requires that ‘}’, and ‘]’ are also enclosed in doublequotes or escaped
|
||
//
|
||
// Single quotes escape everything except a ‘'’
|
||
//
|
||
// There's one other gotcha - ‘~’ at the start of a string needs to be expanded
|
||
// because people always expect that - of course if there is a special character before '/'
|
||
// this is not going to work
|
||
|
||
const (
|
||
tildePrefix = '~'
|
||
needsEscape = " \t\n|&;()<>${}[]*?!\"'`\\"
|
||
needsSingleQuote = "!\n"
|
||
)
|
||
|
||
var (
|
||
doubleQuoteEscaper = strings.NewReplacer(`$`, `\$`, "`", "\\`", `"`, `\"`, `\`, `\\`)
|
||
singleQuoteEscaper = strings.NewReplacer(`'`, `'\''`)
|
||
singleQuoteCoalescer = strings.NewReplacer(`''\'`, `\'`, `\'''`, `\'`)
|
||
)
|
||
|
||
// ShellEscape will escape the provided string.
|
||
// We can't just use go-shellquote here because our preferences for escaping differ from those in that we want:
|
||
//
|
||
// * If the string doesn't require any escaping just leave it as it is.
|
||
// * If the string requires any escaping prefer double quote escaping
|
||
// * If we have ! or newlines then we need to use single quote escaping
|
||
func ShellEscape(toEscape string) string {
|
||
if len(toEscape) == 0 {
|
||
return toEscape
|
||
}
|
||
|
||
start := 0
|
||
|
||
if toEscape[0] == tildePrefix {
|
||
// We're in the forcibly non-escaped section...
|
||
idx := strings.IndexRune(toEscape, '/')
|
||
if idx < 0 {
|
||
idx = len(toEscape)
|
||
} else {
|
||
idx++
|
||
}
|
||
if !strings.ContainsAny(toEscape[:idx], needsEscape) {
|
||
// We'll assume that they intend ~ expansion to occur
|
||
start = idx
|
||
}
|
||
}
|
||
|
||
// Now for simplicity we'll look at the rest of the string
|
||
if !strings.ContainsAny(toEscape[start:], needsEscape) {
|
||
return toEscape
|
||
}
|
||
|
||
// OK we have to do some escaping
|
||
sb := &strings.Builder{}
|
||
_, _ = sb.WriteString(toEscape[:start])
|
||
|
||
// Do we have any characters which absolutely need to be within single quotes - that is simply ! or \n?
|
||
if strings.ContainsAny(toEscape[start:], needsSingleQuote) {
|
||
// We need to single quote escape.
|
||
sb2 := &strings.Builder{}
|
||
_, _ = sb2.WriteRune('\'')
|
||
_, _ = singleQuoteEscaper.WriteString(sb2, toEscape[start:])
|
||
_, _ = sb2.WriteRune('\'')
|
||
_, _ = singleQuoteCoalescer.WriteString(sb, sb2.String())
|
||
return sb.String()
|
||
}
|
||
|
||
// OK we can just use " just escape the things that need escaping
|
||
_, _ = sb.WriteRune('"')
|
||
_, _ = doubleQuoteEscaper.WriteString(sb, toEscape[start:])
|
||
_, _ = sb.WriteRune('"')
|
||
return sb.String()
|
||
}
|