Job control: controlling TTYs and foreground process groups.

Adresses a deadlock with the rolled back change:
https://github.com/google/gvisor/commit/b6a5b950d28e0b474fdad160b88bc15314cf9259
Creating a session from an orphaned process group was causing a lock to be
acquired twice by a single goroutine. This behavior is addressed, and a test
(OrphanRegression) has been added to pty.cc.

Implemented the following ioctls:
- TIOCSCTTY - set controlling TTY
- TIOCNOTTY - remove controlling tty, maybe signal some other processes
- TIOCGPGRP - get foreground process group. Also enables tcgetpgrp().
- TIOCSPGRP - set foreground process group. Also enabled tcsetpgrp().

Next steps are to actually turn terminal-generated control characters (e.g. C^c)
into signals to the proper process groups, and to send SIGTTOU and SIGTTIN when
appropriate.

PiperOrigin-RevId: 270088599

1 files changed, 19 insertions, 0 deletions

diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 56fe7be37..a4cebf46f 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -1287,8 +1287,10 @@ cc_binary(
     srcs = ["pty.cc"],
     linkstatic = 1,
     deps = [
+        "//test/util:capability_util",
         "//test/util:file_descriptor",
         "//test/util:posix_error",
+        "//test/util:pty_util",
         "//test/util:test_main",
         "//test/util:test_util",
         "//test/util:thread_util",
@@ -1301,6 +1303,23 @@ cc_binary(
 )
 
 cc_binary(
+    name = "pty_root_test",
+    testonly = 1,
+    srcs = ["pty_root.cc"],
+    linkstatic = 1,
+    deps = [
+        "//test/util:capability_util",
+        "//test/util:file_descriptor",
+        "//test/util:posix_error",
+        "//test/util:pty_util",
+        "//test/util:test_main",
+        "//test/util:thread_util",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_googletest//:gtest",
+    ],
+)
+
+cc_binary(
     name = "partial_bad_buffer_test",
     testonly = 1,
     srcs = ["partial_bad_buffer.cc"],