diff options
Diffstat (limited to 'test/syscalls/linux/pty.cc')
| -rw-r--r-- | test/syscalls/linux/pty.cc | 393 |
1 files changed, 374 insertions, 19 deletions
diff --git a/test/syscalls/linux/pty.cc b/test/syscalls/linux/pty.cc index d1ab4703f..286388316 100644 --- a/test/syscalls/linux/pty.cc +++ b/test/syscalls/linux/pty.cc @@ -13,13 +13,17 @@ // limitations under the License. #include <fcntl.h> +#include <linux/capability.h> #include <linux/major.h> #include <poll.h> +#include <sched.h> +#include <signal.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/sysmacros.h> #include <sys/types.h> +#include <sys/wait.h> #include <termios.h> #include <unistd.h> @@ -31,8 +35,10 @@ #include "absl/synchronization/notification.h" #include "absl/time/clock.h" #include "absl/time/time.h" +#include "test/util/capability_util.h" #include "test/util/file_descriptor.h" #include "test/util/posix_error.h" +#include "test/util/pty_util.h" #include "test/util/test_util.h" #include "test/util/thread_util.h" @@ -370,25 +376,6 @@ PosixErrorOr<size_t> PollAndReadFd(int fd, void* buf, size_t count, return PosixError(ETIMEDOUT, "Poll timed out"); } -// Opens the slave end of the passed master as R/W and nonblocking. -PosixErrorOr<FileDescriptor> OpenSlave(const FileDescriptor& master) { - // Get pty index. - int n; - int ret = ioctl(master.get(), TIOCGPTN, &n); - if (ret < 0) { - return PosixError(errno, "ioctl(TIOCGPTN) failed"); - } - - // Unlock pts. - int unlock = 0; - ret = ioctl(master.get(), TIOCSPTLCK, &unlock); - if (ret < 0) { - return PosixError(errno, "ioctl(TIOSPTLCK) failed"); - } - - return Open(absl::StrCat("/dev/pts/", n), O_RDWR | O_NONBLOCK); -} - TEST(BasicPtyTest, StatUnopenedMaster) { struct stat s; ASSERT_THAT(stat("/dev/ptmx", &s), SyscallSucceeds()); @@ -1233,6 +1220,374 @@ TEST_F(PtyTest, SetMasterWindowSize) { EXPECT_EQ(retrieved_ws.ws_col, kCols); } +class JobControlTest : public ::testing::Test { + protected: + void SetUp() override { + master_ = ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/ptmx", O_RDWR | O_NONBLOCK)); + slave_ = ASSERT_NO_ERRNO_AND_VALUE(OpenSlave(master_)); + + // Make this a session leader, which also drops the controlling terminal. + // In the gVisor test environment, this test will be run as the session + // leader already (as the sentry init process). + if (!IsRunningOnGvisor()) { + ASSERT_THAT(setsid(), SyscallSucceeds()); + } + } + + // Master and slave ends of the PTY. Non-blocking. + FileDescriptor master_; + FileDescriptor slave_; +}; + +TEST_F(JobControlTest, SetTTYMaster) { + ASSERT_THAT(ioctl(master_.get(), TIOCSCTTY, 0), SyscallSucceeds()); +} + +TEST_F(JobControlTest, SetTTY) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); +} + +TEST_F(JobControlTest, SetTTYNonLeader) { + // Fork a process that won't be the session leader. + pid_t child = fork(); + if (!child) { + // We shouldn't be able to set the terminal. + TEST_PCHECK(ioctl(slave_.get(), TIOCSCTTY, 0)); + _exit(0); + } + + int wstatus; + ASSERT_THAT(waitpid(child, &wstatus, 0), SyscallSucceedsWithValue(child)); + ASSERT_EQ(wstatus, 0); +} + +TEST_F(JobControlTest, SetTTYBadArg) { + // Despite the man page saying arg should be 0 here, Linux doesn't actually + // check. + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 1), SyscallSucceeds()); +} + +TEST_F(JobControlTest, SetTTYDifferentSession) { + SKIP_IF(ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SYS_ADMIN))); + + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + // Fork, join a new session, and try to steal the parent's controlling + // terminal, which should fail. + pid_t child = fork(); + if (!child) { + TEST_PCHECK(setsid() >= 0); + // We shouldn't be able to steal the terminal. + TEST_PCHECK(ioctl(slave_.get(), TIOCSCTTY, 1)); + _exit(0); + } + + int wstatus; + ASSERT_THAT(waitpid(child, &wstatus, 0), SyscallSucceedsWithValue(child)); + ASSERT_EQ(wstatus, 0); +} + +TEST_F(JobControlTest, ReleaseTTY) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + // Make sure we're ignoring SIGHUP, which will be sent to this process once we + // disconnect they TTY. + struct sigaction sa = { + .sa_handler = SIG_IGN, + .sa_flags = 0, + }; + sigemptyset(&sa.sa_mask); + struct sigaction old_sa; + EXPECT_THAT(sigaction(SIGHUP, &sa, &old_sa), SyscallSucceeds()); + EXPECT_THAT(ioctl(slave_.get(), TIOCNOTTY), SyscallSucceeds()); + EXPECT_THAT(sigaction(SIGHUP, &old_sa, NULL), SyscallSucceeds()); +} + +TEST_F(JobControlTest, ReleaseUnsetTTY) { + ASSERT_THAT(ioctl(slave_.get(), TIOCNOTTY), SyscallFailsWithErrno(ENOTTY)); +} + +TEST_F(JobControlTest, ReleaseWrongTTY) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + ASSERT_THAT(ioctl(master_.get(), TIOCNOTTY), SyscallFailsWithErrno(ENOTTY)); +} + +TEST_F(JobControlTest, ReleaseTTYNonLeader) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + pid_t child = fork(); + if (!child) { + TEST_PCHECK(!ioctl(slave_.get(), TIOCNOTTY)); + _exit(0); + } + + int wstatus; + ASSERT_THAT(waitpid(child, &wstatus, 0), SyscallSucceedsWithValue(child)); + ASSERT_EQ(wstatus, 0); +} + +TEST_F(JobControlTest, ReleaseTTYDifferentSession) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + pid_t child = fork(); + if (!child) { + // Join a new session, then try to disconnect. + TEST_PCHECK(setsid() >= 0); + TEST_PCHECK(ioctl(slave_.get(), TIOCNOTTY)); + _exit(0); + } + + int wstatus; + ASSERT_THAT(waitpid(child, &wstatus, 0), SyscallSucceedsWithValue(child)); + ASSERT_EQ(wstatus, 0); +} + +// Used by the child process spawned in ReleaseTTYSignals to track received +// signals. +static int received; + +void sig_handler(int signum) { received |= signum; } + +// When the session leader releases its controlling terminal, the foreground +// process group gets SIGHUP, then SIGCONT. This test: +// - Spawns 2 threads +// - Has thread 1 return 0 if it gets both SIGHUP and SIGCONT +// - Has thread 2 leave the foreground process group, and return non-zero if it +// receives any signals. +// - Has the parent thread release its controlling terminal +// - Checks that thread 1 got both signals +// - Checks that thread 2 didn't get any signals. +TEST_F(JobControlTest, ReleaseTTYSignals) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + received = 0; + struct sigaction sa = { + .sa_handler = sig_handler, + .sa_flags = 0, + }; + sigemptyset(&sa.sa_mask); + sigaddset(&sa.sa_mask, SIGHUP); + sigaddset(&sa.sa_mask, SIGCONT); + sigprocmask(SIG_BLOCK, &sa.sa_mask, NULL); + + pid_t same_pgrp_child = fork(); + if (!same_pgrp_child) { + // The child will wait for SIGHUP and SIGCONT, then return 0. It begins with + // SIGHUP and SIGCONT blocked. We install signal handlers for those signals, + // then use sigsuspend to wait for those specific signals. + TEST_PCHECK(!sigaction(SIGHUP, &sa, NULL)); + TEST_PCHECK(!sigaction(SIGCONT, &sa, NULL)); + sigset_t mask; + sigfillset(&mask); + sigdelset(&mask, SIGHUP); + sigdelset(&mask, SIGCONT); + while (received != (SIGHUP | SIGCONT)) { + sigsuspend(&mask); + } + _exit(0); + } + + // We don't want to block these anymore. + sigprocmask(SIG_UNBLOCK, &sa.sa_mask, NULL); + + // This child will return non-zero if either SIGHUP or SIGCONT are received. + pid_t diff_pgrp_child = fork(); + if (!diff_pgrp_child) { + TEST_PCHECK(!setpgid(0, 0)); + TEST_PCHECK(pause()); + _exit(1); + } + + EXPECT_THAT(setpgid(diff_pgrp_child, diff_pgrp_child), SyscallSucceeds()); + + // Make sure we're ignoring SIGHUP, which will be sent to this process once we + // disconnect they TTY. + struct sigaction sighup_sa = { + .sa_handler = SIG_IGN, + .sa_flags = 0, + }; + sigemptyset(&sighup_sa.sa_mask); + struct sigaction old_sa; + EXPECT_THAT(sigaction(SIGHUP, &sighup_sa, &old_sa), SyscallSucceeds()); + + // Release the controlling terminal, sending SIGHUP and SIGCONT to all other + // processes in this process group. + EXPECT_THAT(ioctl(slave_.get(), TIOCNOTTY), SyscallSucceeds()); + + EXPECT_THAT(sigaction(SIGHUP, &old_sa, NULL), SyscallSucceeds()); + + // The child in the same process group will get signaled. + int wstatus; + EXPECT_THAT(waitpid(same_pgrp_child, &wstatus, 0), + SyscallSucceedsWithValue(same_pgrp_child)); + EXPECT_EQ(wstatus, 0); + + // The other child will not get signaled. + EXPECT_THAT(waitpid(diff_pgrp_child, &wstatus, WNOHANG), + SyscallSucceedsWithValue(0)); + EXPECT_THAT(kill(diff_pgrp_child, SIGKILL), SyscallSucceeds()); +} + +TEST_F(JobControlTest, GetForegroundProcessGroup) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + pid_t foreground_pgid; + pid_t pid; + ASSERT_THAT(ioctl(slave_.get(), TIOCGPGRP, &foreground_pgid), + SyscallSucceeds()); + ASSERT_THAT(pid = getpid(), SyscallSucceeds()); + + ASSERT_EQ(foreground_pgid, pid); +} + +TEST_F(JobControlTest, GetForegroundProcessGroupNonControlling) { + // At this point there's no controlling terminal, so TIOCGPGRP should fail. + pid_t foreground_pgid; + ASSERT_THAT(ioctl(slave_.get(), TIOCGPGRP, &foreground_pgid), + SyscallFailsWithErrno(ENOTTY)); +} + +// This test: +// - sets itself as the foreground process group +// - creates a child process in a new process group +// - sets that child as the foreground process group +// - kills its child and sets itself as the foreground process group. +TEST_F(JobControlTest, SetForegroundProcessGroup) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + // Ignore SIGTTOU so that we don't stop ourself when calling tcsetpgrp. + struct sigaction sa = { + .sa_handler = SIG_IGN, + .sa_flags = 0, + }; + sigemptyset(&sa.sa_mask); + sigaction(SIGTTOU, &sa, NULL); + + // Set ourself as the foreground process group. + ASSERT_THAT(tcsetpgrp(slave_.get(), getpgid(0)), SyscallSucceeds()); + + // Create a new process that just waits to be signaled. + pid_t child = fork(); + if (!child) { + TEST_PCHECK(!pause()); + // We should never reach this. + _exit(1); + } + + // Make the child its own process group, then make it the controlling process + // group of the terminal. + ASSERT_THAT(setpgid(child, child), SyscallSucceeds()); + ASSERT_THAT(tcsetpgrp(slave_.get(), child), SyscallSucceeds()); + + // Sanity check - we're still the controlling session. + ASSERT_EQ(getsid(0), getsid(child)); + + // Signal the child, wait for it to exit, then retake the terminal. + ASSERT_THAT(kill(child, SIGTERM), SyscallSucceeds()); + int wstatus; + ASSERT_THAT(waitpid(child, &wstatus, 0), SyscallSucceedsWithValue(child)); + ASSERT_TRUE(WIFSIGNALED(wstatus)); + ASSERT_EQ(WTERMSIG(wstatus), SIGTERM); + + // Set ourself as the foreground process. + pid_t pgid; + ASSERT_THAT(pgid = getpgid(0), SyscallSucceeds()); + ASSERT_THAT(tcsetpgrp(slave_.get(), pgid), SyscallSucceeds()); +} + +TEST_F(JobControlTest, SetForegroundProcessGroupWrongTTY) { + pid_t pid = getpid(); + ASSERT_THAT(ioctl(slave_.get(), TIOCSPGRP, &pid), + SyscallFailsWithErrno(ENOTTY)); +} + +TEST_F(JobControlTest, SetForegroundProcessGroupNegPgid) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + pid_t pid = -1; + ASSERT_THAT(ioctl(slave_.get(), TIOCSPGRP, &pid), + SyscallFailsWithErrno(EINVAL)); +} + +TEST_F(JobControlTest, SetForegroundProcessGroupEmptyProcessGroup) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + // Create a new process, put it in a new process group, make that group the + // foreground process group, then have the process wait. + pid_t child = fork(); + if (!child) { + TEST_PCHECK(!setpgid(0, 0)); + _exit(0); + } + + // Wait for the child to exit. + int wstatus; + EXPECT_THAT(waitpid(child, &wstatus, 0), SyscallSucceedsWithValue(child)); + // The child's process group doesn't exist anymore - this should fail. + ASSERT_THAT(ioctl(slave_.get(), TIOCSPGRP, &child), + SyscallFailsWithErrno(ESRCH)); +} + +TEST_F(JobControlTest, SetForegroundProcessGroupDifferentSession) { + ASSERT_THAT(ioctl(slave_.get(), TIOCSCTTY, 0), SyscallSucceeds()); + + // Create a new process and put it in a new session. + pid_t child = fork(); + if (!child) { + TEST_PCHECK(setsid() >= 0); + // Tell the parent we're in a new session. + TEST_PCHECK(!raise(SIGSTOP)); + TEST_PCHECK(!pause()); + _exit(1); + } + + // Wait for the child to tell us it's in a new session. + int wstatus; + EXPECT_THAT(waitpid(child, &wstatus, WUNTRACED), + SyscallSucceedsWithValue(child)); + EXPECT_TRUE(WSTOPSIG(wstatus)); + + // Child is in a new session, so we can't make it the foregroup process group. + EXPECT_THAT(ioctl(slave_.get(), TIOCSPGRP, &child), + SyscallFailsWithErrno(EPERM)); + + EXPECT_THAT(kill(child, SIGKILL), SyscallSucceeds()); +} + +// Verify that we don't hang when creating a new session from an orphaned +// process group (b/139968068). Calling setsid() creates an orphaned process +// group, as process groups that contain the session's leading process are +// orphans. +// +// We create 2 sessions in this test. The init process in gVisor is considered +// not to be an orphan (see sessions.go), so we have to create a session from +// which to create a session. The latter session is being created from an +// orphaned process group. +TEST_F(JobControlTest, OrphanRegression) { + pid_t session_2_leader = fork(); + if (!session_2_leader) { + TEST_PCHECK(setsid() >= 0); + + pid_t session_3_leader = fork(); + if (!session_3_leader) { + TEST_PCHECK(setsid() >= 0); + + _exit(0); + } + + int wstatus; + TEST_PCHECK(waitpid(session_3_leader, &wstatus, 0) == session_3_leader); + TEST_PCHECK(wstatus == 0); + + _exit(0); + } + + int wstatus; + ASSERT_THAT(waitpid(session_2_leader, &wstatus, 0), + SyscallSucceedsWithValue(session_2_leader)); + ASSERT_EQ(wstatus, 0); +} + } // namespace } // namespace testing } // namespace gvisor |