diff options
| -rw-r--r-- | pkg/sentry/kernel/thread_group.go | 15 | ||||
| -rw-r--r-- | test/syscalls/linux/pty.cc | 78 |
2 files changed, 88 insertions, 5 deletions
diff --git a/pkg/sentry/kernel/thread_group.go b/pkg/sentry/kernel/thread_group.go index 2eda15303..5814a4eca 100644 --- a/pkg/sentry/kernel/thread_group.go +++ b/pkg/sentry/kernel/thread_group.go @@ -489,11 +489,6 @@ func (tg *ThreadGroup) SetForegroundProcessGroup(tty *TTY, pgid ProcessGroupID) tg.signalHandlers.mu.Lock() defer tg.signalHandlers.mu.Unlock() - // TODO(gvisor.dev/issue/6148): "If tcsetpgrp() is called by a member of a - // background process group in its session, and the calling process is not - // blocking or ignoring SIGTTOU, a SIGTTOU signal is sent to all members of - // this background process group." - // tty must be the controlling terminal. if tg.tty != tty { return -1, linuxerr.ENOTTY @@ -516,6 +511,16 @@ func (tg *ThreadGroup) SetForegroundProcessGroup(tty *TTY, pgid ProcessGroupID) return -1, linuxerr.EPERM } + signalAction := tg.signalHandlers.actions[linux.SIGTTOU] + // If the calling process is a member of a background group, a SIGTTOU + // signal is sent to all members of this background process group. + // We need also need to check whether it is ignoring or blocking SIGTTOU. + ignored := signalAction.Handler == linux.SIG_IGN + blocked := tg.leader.signalMask == linux.SignalSetOf(linux.SIGTTOU) + if tg.processGroup.id != tg.processGroup.session.foreground.id && !ignored && !blocked { + tg.leader.sendSignalLocked(SignalInfoPriv(linux.SIGTTOU), true) + } + tg.processGroup.session.foreground.id = pgid return 0, nil } diff --git a/test/syscalls/linux/pty.cc b/test/syscalls/linux/pty.cc index 5ff1f12a0..c008c89e7 100644 --- a/test/syscalls/linux/pty.cc +++ b/test/syscalls/linux/pty.cc @@ -1640,6 +1640,84 @@ TEST_F(JobControlTest, DISABLED_SetForegroundProcessGroup) { ASSERT_NO_ERRNO(res); } +// This test verifies if a SIGTTOU signal is sent to the calling process's group +// when tcsetpgrp is called by a background process +TEST_F(JobControlTest, SetForegroundProcessGroupSIGTTOUBackground) { + auto res = RunInChild([=]() { + TEST_PCHECK(setsid() >= 0); + TEST_PCHECK(!ioctl(replica_.get(), TIOCSCTTY, 0)); + pid_t grandchild = fork(); + if (!grandchild) { + // Assign a different pgid to the child so it will result as + // a background process. + TEST_PCHECK(!setpgid(grandchild, getpid())); + TEST_PCHECK(!tcsetpgrp(replica_.get(), getpgid(0))); + // We should never reach this. + _exit(1); + } + int wstatus; + TEST_PCHECK(waitpid(grandchild, &wstatus, WSTOPPED) == grandchild); + TEST_PCHECK(WSTOPSIG(wstatus) == SIGTTOU); + }); + ASSERT_NO_ERRNO(res); +} + +// This test verifies that a SIGTTOU signal is not delivered to +// a background process which calls tcsetpgrp and is ignoring SIGTTOU +TEST_F(JobControlTest, SetForegroundProcessGroupSIGTTOUIgnored) { + auto res = RunInChild([=]() { + TEST_PCHECK(setsid() >= 0); + TEST_PCHECK(!ioctl(replica_.get(), TIOCSCTTY, 0)); + pid_t grandchild = fork(); + if (!grandchild) { + // Ignore SIGTTOU so the child in background won't + // be stopped when it will call tcsetpgrp + struct sigaction sa = {}; + sa.sa_handler = SIG_IGN; + sa.sa_flags = 0; + sigemptyset(&sa.sa_mask); + sigaction(SIGTTOU, &sa, NULL); + // Assign a different pgid to the child so it will result as + // a background process. + TEST_PCHECK(!setpgid(grandchild, getpid())); + TEST_PCHECK(!tcsetpgrp(replica_.get(), getpgid(0))); + _exit(0); + } + int wstatus; + TEST_PCHECK(waitpid(grandchild, &wstatus, WSTOPPED) == grandchild); + TEST_PCHECK(WSTOPSIG(wstatus) != SIGTTOU); + TEST_PCHECK(WIFEXITED(wstatus)); + }); + ASSERT_NO_ERRNO(res); +} + +// This test verifies that a SIGTTOU signal is not delivered to +// a background process which calls tcsetpgrp and is blocking SIGTTOU +TEST_F(JobControlTest, SetForegroundProcessGroupSIGTTOUBlocked) { + auto res = RunInChild([=]() { + TEST_PCHECK(setsid() >= 0); + TEST_PCHECK(!ioctl(replica_.get(), TIOCSCTTY, 0)); + pid_t grandchild = fork(); + if (!grandchild) { + // Block SIGTTOU so the child in background won't + // be stopped when it will call tcsetpgrp + sigset_t signal_set; + sigemptyset(&signal_set); + sigaddset(&signal_set, SIGTTOU); + sigprocmask(SIG_BLOCK, &signal_set, NULL); + // Assign a different pgid to the child so it will result as + // a background process. + TEST_PCHECK(!setpgid(grandchild, getpid())); + TEST_PCHECK(!tcsetpgrp(replica_.get(), getpgid(0))); + _exit(0); + } + int wstatus; + TEST_PCHECK(waitpid(grandchild, &wstatus, WSTOPPED) == grandchild); + TEST_PCHECK(WSTOPSIG(wstatus) != SIGTTOU); + }); + ASSERT_NO_ERRNO(res); +} + TEST_F(JobControlTest, SetForegroundProcessGroupWrongTTY) { pid_t pid = getpid(); ASSERT_THAT(ioctl(replica_.get(), TIOCSPGRP, &pid), |