[PATCH 1/6] qga: Add process termination functionality

[Alexander Ivanov <alexander.ivanov@virtuozzo.com>]

We need to terminate processes executed with guest-exec command. Add
guest-exec-terminate command for process termination by PID.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
 qga/commands-common.h |  2 ++
 qga/commands-win32.c  | 64 +++++++++++++++++++++++++++++++++++++++++++
 qga/commands.c        | 34 +++++++++++++++++++++++
 qga/qapi-schema.json  | 13 +++++++++
 4 files changed, 113 insertions(+)

diff --git a/qga/commands-common.h b/qga/commands-common.h
index 8c1c56aac9..34b9a22578 100644
--- a/qga/commands-common.h
+++ b/qga/commands-common.h
@@ -80,4 +80,6 @@ GuestFileRead *guest_file_read_unsafe(GuestFileHandle *gfh,
  */
 char *qga_get_host_name(Error **errp);
 
+int kill_process_tree(int64_t pid);
+
 #endif
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 697c65507c..5aa43a9ed7 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -27,6 +27,7 @@
 #include <lm.h>
 #include <wtsapi32.h>
 #include <wininet.h>
+#include <tlhelp32.h>
 
 #include "guest-agent-core.h"
 #include "vss-win32.h"
@@ -2522,3 +2523,66 @@ GuestCpuStatsList *qmp_guest_get_cpustats(Error **errp)
     error_setg(errp, QERR_UNSUPPORTED);
     return NULL;
 }
+
+int kill_process_tree(int64_t pid)
+{
+    PROCESSENTRY32 proc_entry;
+    HANDLE snapshot, process;
+    GList *pid_entry, *pid_list = NULL;
+    bool added, success;
+    int res = 0;
+
+    snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+    if (snapshot == INVALID_HANDLE_VALUE) {
+        return GetLastError();
+    }
+
+    pid_list = g_list_append(pid_list, GUINT_TO_POINTER(pid));
+
+    proc_entry.dwSize = sizeof(PROCESSENTRY32);
+    do {
+        added = false;
+        for (success = Process32First(snapshot, &proc_entry);
+             success; success = Process32Next(snapshot, &proc_entry)) {
+            gpointer ppid_p, pid_p;
+            ppid_p = GUINT_TO_POINTER(proc_entry.th32ParentProcessID);
+            pid_p = GUINT_TO_POINTER(proc_entry.th32ProcessID);
+            if (g_list_find(pid_list, ppid_p) && !g_list_find(pid_list, pid_p)) {
+                pid_list = g_list_append(pid_list, pid_p);
+                added = true;
+            }
+        }
+    } while (added);
+
+    for (success = Process32First(snapshot, &proc_entry);
+         success; success = Process32Next(snapshot, &proc_entry)) {
+        if (g_list_find(pid_list, GUINT_TO_POINTER(proc_entry.th32ProcessID))) {
+            g_debug("killing pid=%u ppid=%u name=%s",
+                (guint)proc_entry.th32ProcessID,
+                (guint)proc_entry.th32ParentProcessID,
+                proc_entry.szExeFile);
+        }
+    }
+
+    CloseHandle(snapshot);
+
+    for (pid_entry = pid_list; pid_entry; pid_entry = pid_entry->next) {
+        pid = GPOINTER_TO_UINT(pid_entry->data);
+        process = OpenProcess(PROCESS_TERMINATE, FALSE, pid);
+        if (process == INVALID_HANDLE_VALUE) {
+            if (!res) {
+                res = GetLastError();
+                if (res == ERROR_FILE_NOT_FOUND) {
+                    res = 0;
+                }
+            }
+            continue;
+        }
+        TerminateProcess(process, 255);
+        CloseHandle(process);
+    }
+
+    g_list_free(pid_list);
+
+    return res;
+}
diff --git a/qga/commands.c b/qga/commands.c
index ce172edd2d..af8459c587 100644
--- a/qga/commands.c
+++ b/qga/commands.c
@@ -529,6 +529,40 @@ done:
     return ge;
 }
 
+void qmp_guest_exec_terminate(int64_t pid, Error **errp)
+{
+    GuestExecInfo *gei;
+
+    slog("guest-exec-terminate called, pid: %u", (uint32_t)pid);
+
+    gei = guest_exec_info_find(pid);
+    if (gei == NULL) {
+        error_setg(errp, QERR_INVALID_PARAMETER, "pid");
+        return;
+    }
+
+    if (gei->finished) {
+        return;
+    }
+
+#ifdef G_OS_WIN32
+    char buf[32];
+    int res;
+
+    res = kill_process_tree(pid);
+    if (res != 0) {
+        snprintf(buf, sizeof(buf), "win32 err %d", res);
+        error_setg(errp, QERR_QGA_COMMAND_FAILED, buf);
+    }
+#else
+    if (kill(pid, SIGKILL) < 0) {
+        if (errno != ESRCH) {
+            error_setg(errp, QERR_QGA_COMMAND_FAILED, strerror(errno));
+        }
+    }
+#endif
+}
+
 /* Convert GuestFileWhence (either a raw integer or an enum value) into
  * the guest's SEEK_ constants.  */
 int ga_parse_whence(GuestFileWhence *whence, Error **errp)
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 876e2a8ea8..b39be4cdc2 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -1326,6 +1326,19 @@
                '*input-data': 'str', '*capture-output': 'GuestExecCaptureOutput' },
   'returns': 'GuestExec' }
 
+##
+# @guest-exec-terminate:
+#
+# Terminate process associated with PID retrieved via guest-exec.
+#
+# @pid: pid returned from guest-exec
+#
+# Returns: Nothing on success.
+#
+# Since: 8.2
+##
+{ 'command': 'guest-exec-terminate',
+  'data':    { 'pid': 'int' } }
 
 ##
 # @GuestHostName:
-- 
2.34.1