Complete async signal delivery support in vfs2.

- Support FIOASYNC, FIO{SET,GET}OWN, SIOC{G,S}PGRP (refactor getting/setting
  owner in the process).
- Unset signal recipient when setting owner with pid == 0 and
  valid owner type.

Updates #2923.

PiperOrigin-RevId: 319231420

2 files changed, 58 insertions, 0 deletions

diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD
index 36c178e4a..88ed36b69 100644
--- a/test/syscalls/BUILD
+++ b/test/syscalls/BUILD
@@ -288,6 +288,7 @@ syscall_test(
     size = "medium",
     add_overlay = True,
     test = "//test/syscalls/linux:ioctl_test",
+    vfs2 = "True",
 )
 
 syscall_test(
diff --git a/test/syscalls/linux/fcntl.cc b/test/syscalls/linux/fcntl.cc
index 4b9b4db99..5467fa2c8 100644
--- a/test/syscalls/linux/fcntl.cc
+++ b/test/syscalls/linux/fcntl.cc
@@ -1031,6 +1031,30 @@ TEST(FcntlTest, SetOwnPgrp) {
   MaybeSave();
 }
 
+TEST(FcntlTest, SetOwnUnset) {
+  FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE(
+      Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0));
+
+  // Set and unset pid.
+  pid_t pid;
+  EXPECT_THAT(pid = getpid(), SyscallSucceeds());
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, pid), SyscallSucceeds());
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, 0), SyscallSucceeds());
+
+  EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN),
+              SyscallSucceedsWithValue(0));
+
+  // Set and unset pgid.
+  pid_t pgid;
+  EXPECT_THAT(pgid = getpgrp(), SyscallSucceeds());
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, -pgid), SyscallSucceeds());
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, 0), SyscallSucceeds());
+
+  EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN),
+              SyscallSucceedsWithValue(0));
+  MaybeSave();
+}
+
 // F_SETOWN flips the sign of negative values, an operation that is guarded
 // against overflow.
 TEST(FcntlTest, SetOwnOverflow) {
@@ -1141,6 +1165,39 @@ TEST(FcntlTest, SetOwnExPgrp) {
   MaybeSave();
 }
 
+TEST(FcntlTest, SetOwnExUnset) {
+  SKIP_IF(IsRunningWithVFS1());
+
+  FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE(
+      Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0));
+
+  // Set and unset pid.
+  f_owner_ex owner = {};
+  owner.type = F_OWNER_PID;
+  EXPECT_THAT(owner.pid = getpid(), SyscallSucceeds());
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner),
+              SyscallSucceeds());
+  owner.pid = 0;
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner),
+              SyscallSucceeds());
+
+  EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN),
+              SyscallSucceedsWithValue(0));
+
+  // Set and unset pgid.
+  owner.type = F_OWNER_PGRP;
+  EXPECT_THAT(owner.pid = getpgrp(), SyscallSucceeds());
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner),
+              SyscallSucceeds());
+  owner.pid = 0;
+  ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner),
+              SyscallSucceeds());
+
+  EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN),
+              SyscallSucceedsWithValue(0));
+  MaybeSave();
+}
+
 TEST(FcntlTest, GetOwnExTid) {
   FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE(
       Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0));