Merge pull request #6438 from gystemd:tcsetpgrp_SIGTTOU

PiperOrigin-RevId: 392774712

1 files changed, 78 insertions, 0 deletions

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),