mirror of
https://codeberg.org/cunicu/cunicu.git
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73 lines
1.6 KiB
Go
73 lines
1.6 KiB
Go
// SPDX-FileCopyrightText: 2015 CoreOS, Inc.
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// SPDX-FileCopyrightText: 2023-2025 Steffen Vogel <post@steffenvogel.de>
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// SPDX-License-Identifier: Apache-2.0
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package systemd
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import (
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"os"
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"strconv"
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"strings"
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"syscall"
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)
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const (
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// listenFdsStart corresponds to `SD_LISTEN_FDS_START`.
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listenFdsStart = 3
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)
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// Files returns a slice containing a `os.File` object for each
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// file descriptor passed to this process via systemd fd-passing protocol.
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//
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// The order of the file descriptors is preserved in the returned slice.
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// `unsetEnv` is typically set to `true` in order to avoid clashes in
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// fd usage and to avoid leaking environment flags to child processes.
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func Files(unsetEnv bool) []*os.File {
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if unsetEnv {
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defer os.Unsetenv("LISTEN_PID")
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defer os.Unsetenv("LISTEN_FDS")
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defer os.Unsetenv("LISTEN_FDNAMES")
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}
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pid, err := strconv.Atoi(os.Getenv("LISTEN_PID"))
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if err != nil || pid != os.Getpid() {
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return nil
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}
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nfds, err := strconv.Atoi(os.Getenv("LISTEN_FDS"))
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if err != nil || nfds == 0 {
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return nil
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}
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names := strings.Split(os.Getenv("LISTEN_FDNAMES"), ":")
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files := make([]*os.File, 0, nfds)
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for fd := listenFdsStart; fd < listenFdsStart+nfds; fd++ {
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syscall.CloseOnExec(fd)
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name := "LISTEN_FD_" + strconv.Itoa(fd)
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if offset := fd - listenFdsStart; offset < len(names) && len(names[offset]) > 0 {
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name = names[offset]
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}
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files = append(files, os.NewFile(uintptr(fd), name))
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}
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return files
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}
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func NumFiles() int {
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lpid, err := strconv.Atoi(os.Getenv("LISTEN_PID"))
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if err != nil || lpid != os.Getpid() {
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return 0
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}
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nfds, err := strconv.Atoi(os.Getenv("LISTEN_FDS"))
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if err != nil {
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return 0
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}
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return nfds
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}
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