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51dc80be5b
This function casts its argument to int32 before passing it to the system call, so that big-endian CPUs read the lower rather than the upper 32 bits of the pid. This also gets rid of the last import of "unsafe" in the Unix build. I changed syscall to x/sys/unix while I was at it, to remove one more import line. The constants and types there are aliases for their syscall counterparts.
72 lines
1.4 KiB
Go
72 lines
1.4 KiB
Go
//go:build !aix && !solaris && !windows
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// +build !aix,!solaris,!windows
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package backend
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import (
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"os"
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"os/exec"
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"os/signal"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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"golang.org/x/sys/unix"
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)
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func tcsetpgrp(fd int, pid int) error {
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// IoctlSetPointerInt silently casts to int32 internally,
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// so this assumes pid fits in 31 bits.
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return unix.IoctlSetPointerInt(fd, unix.TIOCSPGRP, pid)
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}
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func startForeground(cmd *exec.Cmd) (bg func() error, err error) {
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// open the TTY, we need the file descriptor
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tty, err := os.OpenFile("/dev/tty", os.O_RDWR, 0)
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if err != nil {
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debug.Log("unable to open tty: %v", err)
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bg = func() error {
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return nil
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}
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return bg, cmd.Start()
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}
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signal.Ignore(unix.SIGTTIN)
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signal.Ignore(unix.SIGTTOU)
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// run the command in its own process group
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cmd.SysProcAttr = &unix.SysProcAttr{
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Setpgid: true,
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}
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// start the process
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err = cmd.Start()
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if err != nil {
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_ = tty.Close()
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return nil, errors.Wrap(err, "cmd.Start")
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}
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// move the command's process group into the foreground
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prev := unix.Getpgrp()
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err = tcsetpgrp(int(tty.Fd()), cmd.Process.Pid)
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if err != nil {
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_ = tty.Close()
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return nil, err
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}
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bg = func() error {
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signal.Reset(unix.SIGTTIN)
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signal.Reset(unix.SIGTTOU)
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// reset the foreground process group
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err = tcsetpgrp(int(tty.Fd()), prev)
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if err != nil {
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_ = tty.Close()
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return err
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}
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return tty.Close()
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}
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return bg, nil
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}
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