forked from rook/rook
Joshua Hoblitt
ae375e10b1
Command arguments are passed to the kernel as a vector, so joining them with plain spaces loses the boundaries between them. An argument holding whitespace or a shell metacharacter reads back as several arguments, or as several commands. FormatCommand renders a command and its arguments as a single line a POSIX shell reads back as the original vector. Quoting is minimal: an argument is single-quoted only when it contains a character the shell would not pass through literally, so the flag-heavy command lines rook builds stay readable. Signed-off-by: Joshua Hoblitt <josh@hoblitt.com>
66 lines
2.0 KiB
Go
66 lines
2.0 KiB
Go
/*
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Copyright 2026 The Rook Authors. All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package exec
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import "strings"
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// safeArgChars are the non-alphanumeric characters a POSIX shell passes through
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// literally, matching the set used by Python's shlex.quote.
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const safeArgChars = "@%+=:,./-_"
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// FormatCommand renders a command and its arguments as a single line that can be
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// pasted into a POSIX shell. Arguments are passed to the kernel as a vector, so
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// joining them with plain spaces loses the boundaries between them: an argument
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// containing whitespace or a shell metacharacter reads back as several arguments,
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// or as several commands.
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func FormatCommand(command string, arg ...string) string {
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quoted := make([]string, 0, len(arg)+1)
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quoted = append(quoted, quoteArg(command))
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for _, a := range arg {
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quoted = append(quoted, quoteArg(a))
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}
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return strings.Join(quoted, " ")
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}
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// quoteArg single-quotes arg if a shell would not read it back verbatim.
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func quoteArg(arg string) string {
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if arg == "" {
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return "''"
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}
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if !needsQuoting(arg) {
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return arg
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}
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// A single quote cannot be escaped inside single quotes; the quoted run has to
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// be closed, the quote emitted outside it, and a new run opened.
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return "'" + strings.ReplaceAll(arg, "'", `'\''`) + "'"
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}
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func needsQuoting(arg string) bool {
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for _, r := range arg {
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switch {
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case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r >= '0' && r <= '9':
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case strings.ContainsRune(safeArgChars, r):
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default:
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return true
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}
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}
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return false
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}
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