From 2ed08ad6f2484080813ec91728da8854b091caf8 Mon Sep 17 00:00:00 2001
From: Tu Dinh <dinhngtu@users.noreply.github.com>
Date: Tue, 19 Jan 2021 22:24:41 +0100
Subject: [PATCH] libpsl: add KillProcess and WaitPid functions

These functions are used by powershell-unix to clean up SSH processes
after they exit.
---
 src/libpsl-native/src/CMakeLists.txt  |  4 +++-
 src/libpsl-native/src/killprocess.cpp | 25 ++++++++++++++++++++++
 src/libpsl-native/src/killprocess.h   | 13 ++++++++++++
 src/libpsl-native/src/waitpid.cpp     | 30 +++++++++++++++++++++++++++
 src/libpsl-native/src/waitpid.h       | 13 ++++++++++++
 5 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 src/libpsl-native/src/killprocess.cpp
 create mode 100644 src/libpsl-native/src/killprocess.h
 create mode 100644 src/libpsl-native/src/waitpid.cpp
 create mode 100644 src/libpsl-native/src/waitpid.h

diff --git a/src/libpsl-native/src/CMakeLists.txt b/src/libpsl-native/src/CMakeLists.txt
index 4202c96..cc81571 100644
--- a/src/libpsl-native/src/CMakeLists.txt
+++ b/src/libpsl-native/src/CMakeLists.txt
@@ -27,7 +27,9 @@ add_library(psl-native SHARED
   createsymlink.cpp
   followsymlink.cpp
   createprocess.cpp
-  nativesyslog.cpp)
+  nativesyslog.cpp
+  killprocess.cpp
+  waitpid.cpp)
 
 check_function_exists(sysconf HAVE_SYSCONF)
 
diff --git a/src/libpsl-native/src/killprocess.cpp b/src/libpsl-native/src/killprocess.cpp
new file mode 100644
index 0000000..811dd3c
--- /dev/null
+++ b/src/libpsl-native/src/killprocess.cpp
@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+//! @brief kill a process with SIGKILL
+
+#include "killprocess.h"
+
+#include <sys/types.h>
+#include <signal.h>
+
+//! @brief kill a process with SIGKILL
+//!
+//! KillProcess
+//!
+//! @param[in] pid
+//! @parblock
+//! The target PID to kill.
+//! @endparblock
+//!
+//! @retval true if signal successfully sent, false otherwise
+//!
+bool KillProcess(pid_t pid)
+{
+    return kill(pid, SIGKILL) == 0;
+}
diff --git a/src/libpsl-native/src/killprocess.h b/src/libpsl-native/src/killprocess.h
new file mode 100644
index 0000000..d7dee5c
--- /dev/null
+++ b/src/libpsl-native/src/killprocess.h
@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+#pragma once
+
+#include "pal.h"
+#include <sys/types.h>
+
+PAL_BEGIN_EXTERNC
+
+bool KillProcess(pid_t pid);
+
+PAL_END_EXTERNC
diff --git a/src/libpsl-native/src/waitpid.cpp b/src/libpsl-native/src/waitpid.cpp
new file mode 100644
index 0000000..379dde4
--- /dev/null
+++ b/src/libpsl-native/src/waitpid.cpp
@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+//! @brief wait for a child process to stop or terminate
+
+#include "waitpid.h"
+
+#include <sys/types.h>
+#include <sys/wait.h>
+
+//! @brief wait for a child process to stop or terminate
+//!
+//! WaitPid
+//!
+//! @param[in] pid
+//! @parblock
+//! The target PID to wait for.
+//! @endparblock
+//!
+//! @param[in] nohang
+//! @parblock
+//! Whether to block while waiting for the process.
+//! @endparblock
+//!
+//! @retval PID of exited child, or -1 if error
+//!
+pid_t WaitPid(pid_t pid, bool nohang)
+{
+    return waitpid(pid, NULL, nohang ? WNOHANG : 0);
+}
diff --git a/src/libpsl-native/src/waitpid.h b/src/libpsl-native/src/waitpid.h
new file mode 100644
index 0000000..e33baf5
--- /dev/null
+++ b/src/libpsl-native/src/waitpid.h
@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+#pragma once
+
+#include "pal.h"
+#include <sys/types.h>
+
+PAL_BEGIN_EXTERNC
+
+pid_t WaitPid(pid_t pid, bool nohang);
+
+PAL_END_EXTERNC