12832851c6
SUSE has /bin/logger, everybody else has /usr/bin/logger, so try both. Fixes https://github.com/rfjakob/gocryptfs/issues/225
106 lines
2.9 KiB
Go
106 lines
2.9 KiB
Go
package main
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import (
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"fmt"
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"os"
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"os/exec"
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"os/signal"
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"syscall"
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"github.com/rfjakob/gocryptfs/internal/exitcodes"
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"github.com/rfjakob/gocryptfs/internal/syscallcompat"
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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// The child sends us USR1 if the mount was successful. Exit with error code
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// 0 if we get it.
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func exitOnUsr1() {
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c := make(chan os.Signal, 1)
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signal.Notify(c, syscall.SIGUSR1)
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go func() {
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<-c
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os.Exit(0)
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}()
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}
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// forkChild - execute ourselves once again, this time with the "-fg" flag, and
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// wait for SIGUSR1 or child exit.
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// This is a workaround for the missing true fork function in Go.
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func forkChild() int {
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name := os.Args[0]
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newArgs := []string{"-fg", fmt.Sprintf("-notifypid=%d", os.Getpid())}
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newArgs = append(newArgs, os.Args[1:]...)
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c := exec.Command(name, newArgs...)
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c.Stdout = os.Stdout
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c.Stderr = os.Stderr
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c.Stdin = os.Stdin
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exitOnUsr1()
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err := c.Start()
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if err != nil {
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tlog.Fatal.Printf("forkChild: starting %s failed: %v\n", name, err)
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return exitcodes.ForkChild
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}
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err = c.Wait()
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if err != nil {
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if exiterr, ok := err.(*exec.ExitError); ok {
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if waitstat, ok := exiterr.Sys().(syscall.WaitStatus); ok {
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os.Exit(waitstat.ExitStatus())
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}
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}
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tlog.Fatal.Printf("forkChild: wait returned an unknown error: %v\n", err)
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return exitcodes.ForkChild
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}
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// The child exited with 0 - let's do the same.
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return 0
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}
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// redirectStdFds redirects stderr and stdout to syslog; stdin to /dev/null
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func redirectStdFds() {
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// Create a pipe pair "pw" -> "pr" and start logger reading from "pr".
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// We do it ourselves instead of using StdinPipe() because we need access
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// to the fd numbers.
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pr, pw, err := os.Pipe()
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if err != nil {
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tlog.Warn.Printf("redirectStdFds: could not create pipe: %v\n", err)
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return
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}
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tag := fmt.Sprintf("gocryptfs-%d-logger", os.Getpid())
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// SUSE has /bin/logger, everybody else has /usr/bin/logger.
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for _, path := range []string{"/usr/bin/logger", "/bin/logger"} {
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cmd := exec.Command(path, "-t", tag)
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cmd.Stdin = pr
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err = cmd.Start()
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if err == nil {
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break
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}
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}
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if err != nil {
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tlog.Warn.Printf("redirectStdFds: could not start logger: %v\n", err)
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return
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}
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// The logger now reads on "pr". We can close it.
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pr.Close()
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// Redirect stout and stderr to "pw".
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err = syscallcompat.Dup3(int(pw.Fd()), 1, 0)
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if err != nil {
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tlog.Warn.Printf("redirectStdFds: stdout dup error: %v\n", err)
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}
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syscallcompat.Dup3(int(pw.Fd()), 2, 0)
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if err != nil {
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tlog.Warn.Printf("redirectStdFds: stderr dup error: %v\n", err)
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}
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// Our stout and stderr point to "pw". We can close the extra copy.
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pw.Close()
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// Redirect stdin to /dev/null
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nullFd, err := os.Open("/dev/null")
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if err != nil {
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tlog.Warn.Printf("redirectStdFds: could not open /dev/null: %v\n", err)
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return
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}
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err = syscallcompat.Dup3(int(nullFd.Fd()), 0, 0)
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if err != nil {
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tlog.Warn.Printf("redirectStdFds: stdin dup error: %v\n", err)
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}
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nullFd.Close()
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}
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