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syscall: restore signal mask after setting foreground process group

Fixes #37217

Change-Id: I0151bb77fc4c4552d1b19c31d784943b72f84b80
Reviewed-on: https://go-review.googlesource.com/c/go/+/313653
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
This commit is contained in:
Ian Lance Taylor 2021-04-26 17:27:58 -07:00
parent 39844971fb
commit 7d22c2181b
5 changed files with 56 additions and 9 deletions

View File

@ -90,8 +90,6 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
// Fork succeeded, now in child.
runtime_AfterForkInChild()
// Enable tracing if requested.
if sys.Ptrace {
_, _, err1 = RawSyscall(SYS_PTRACE, uintptr(PTRACE_TRACEME), 0, 0)
@ -137,6 +135,10 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
}
}
// Restore the signal mask. We do this after TIOCSPGRP to avoid
// having the kernel send a SIGTTOU signal to the process group.
runtime_AfterForkInChild()
// Chroot
if chroot != nil {
_, _, err1 = RawSyscall(SYS_CHROOT, uintptr(unsafe.Pointer(chroot)), 0, 0)

View File

@ -116,8 +116,6 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
// Fork succeeded, now in child.
runtime_AfterForkInChild()
// Session ID
if sys.Setsid {
_, err1 = setsid()
@ -153,6 +151,10 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
}
}
// Restore the signal mask. We do this after TIOCSPGRP to avoid
// having the kernel send a SIGTTOU signal to the process group.
runtime_AfterForkInChild()
// Chroot
if chroot != nil {
err1 = chroot1(uintptr(unsafe.Pointer(chroot)))

View File

@ -91,8 +91,6 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
// Fork succeeded, now in child.
runtime_AfterForkInChild()
// Enable tracing if requested.
if sys.Ptrace {
if err := ptrace(PTRACE_TRACEME, 0, 0, 0); err != nil {
@ -136,6 +134,10 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
}
}
// Restore the signal mask. We do this after TIOCSPGRP to avoid
// having the kernel send a SIGTTOU signal to the process group.
runtime_AfterForkInChild()
// Chroot
if chroot != nil {
_, _, err1 = rawSyscall(abi.FuncPCABI0(libc_chroot_trampoline), uintptr(unsafe.Pointer(chroot)), 0, 0)

View File

@ -233,8 +233,6 @@ func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, att
// Fork succeeded, now in child.
runtime_AfterForkInChild()
// Enable the "keep capabilities" flag to set ambient capabilities later.
if len(sys.AmbientCaps) > 0 {
_, _, err1 = RawSyscall6(SYS_PRCTL, PR_SET_KEEPCAPS, 1, 0, 0, 0, 0)
@ -294,6 +292,10 @@ func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, att
}
}
// Restore the signal mask. We do this after TIOCSPGRP to avoid
// having the kernel send a SIGTTOU signal to the process group.
runtime_AfterForkInChild()
// Unshare
if sys.Unshareflags != 0 {
_, _, err1 = RawSyscall(SYS_UNSHARE, sys.Unshareflags, 0, 0)

View File

@ -167,11 +167,13 @@ func TestPgid(t *testing.T) {
func TestForeground(t *testing.T) {
signal.Ignore(syscall.SIGTTIN, syscall.SIGTTOU)
defer signal.Reset()
tty, err := os.OpenFile("/dev/tty", os.O_RDWR, 0)
if err != nil {
t.Skipf("Can't test Foreground. Couldn't open /dev/tty: %s", err)
}
defer tty.Close()
// This should really be pid_t, however _C_int (aka int32) is generally
// equivalent.
@ -216,8 +218,45 @@ func TestForeground(t *testing.T) {
if errno != 0 {
t.Fatalf("TIOCSPGRP failed with error code: %s", errno)
}
}
signal.Reset()
func TestForegroundSignal(t *testing.T) {
tty, err := os.OpenFile("/dev/tty", os.O_RDWR, 0)
if err != nil {
t.Skipf("couldn't open /dev/tty: %s", err)
}
defer tty.Close()
ch1 := make(chan os.Signal, 1)
ch2 := make(chan bool)
signal.Notify(ch1, syscall.SIGTTIN, syscall.SIGTTOU)
defer signal.Stop(ch1)
go func() {
cmd := create(t)
cmd.proc.SysProcAttr = &syscall.SysProcAttr{
Ctty: int(tty.Fd()),
Foreground: true,
}
cmd.Start()
cmd.Stop()
close(ch2)
}()
timer := time.NewTimer(30 * time.Second)
defer timer.Stop()
for {
select {
case sig := <-ch1:
t.Errorf("unexpected signal %v", sig)
case <-ch2:
// Success.
return
case <-timer.C:
t.Fatal("timed out waiting for child process")
}
}
}
// Test a couple of cases that SysProcAttr can't handle. Issue 29458.