qemu: add patch for qga guest-shutdown command

Ref: https://github.com/openwrt/packages/issues/14244
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

utils/qemu/Makefile

@@ -10,7 +10,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=qemu
 PKG_VERSION:=5.0.0
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_HASH:=2f13a92a0fa5c8b69ff0796b59b86b080bbb92ebad5d301a7724dd06b5e78cb6
 PKG_SOURCE_URL:=http://download.qemu.org/

utils/qemu/patches/0007-qga-invoke-separate-applets-for-guest-shutdown-modes.patch

@@ -0,0 +1,47 @@
+From 80ec6872aceb18c68b1cf5b6f8acd6ad667cbd4f Mon Sep 17 00:00:00 2001
+From: Yousong Zhou <yszhou4tech@gmail.com>
+Date: Thu, 17 Dec 2020 15:55:55 +0800
+Subject: [PATCH] qga: invoke separate applets for guest-shutdown modes
+
+/sbin/shutdown is not available on OpenWrt by default
+
+Origin: "main/qemu: fix shutdown from guest agent"
+https://gitlab.alpinelinux.org/alpine/aports/commit/76b81b486480fd9c3294cd420bcf2df01c27790d
+---
+ qga/commands-posix.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/qga/commands-posix.c b/qga/commands-posix.c
+index a52af0315f..623d856c64 100644
+--- a/qga/commands-posix.c
++++ b/qga/commands-posix.c
+@@ -84,6 +84,7 @@ static void ga_wait_child(pid_t pid, int *status, Error **errp)
+ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **errp)
+ {
+     const char *shutdown_flag;
++    const char *fallback_cmd = NULL;
+     Error *local_err = NULL;
+     pid_t pid;
+     int status;
+@@ -91,10 +92,13 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **errp)
+     slog("guest-shutdown called, mode: %s", mode);
+     if (!has_mode || strcmp(mode, "powerdown") == 0) {
+         shutdown_flag = "-P";
++        fallback_cmd = "/sbin/poweroff";
+     } else if (strcmp(mode, "halt") == 0) {
+         shutdown_flag = "-H";
++        fallback_cmd = "/sbin/halt";
+     } else if (strcmp(mode, "reboot") == 0) {
+         shutdown_flag = "-r";
++        fallback_cmd = "/sbin/reboot";
+     } else {
+         error_setg(errp,
+                    "mode is invalid (valid values are: halt|powerdown|reboot");
+@@ -111,6 +115,7 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **errp)
+ 
+         execle("/sbin/shutdown", "shutdown", "-h", shutdown_flag, "+0",
+                "hypervisor initiated shutdown", (char*)NULL, environ);
++        execle(fallback_cmd, fallback_cmd, (char*)NULL, environ);
+         _exit(EXIT_FAILURE);
+     } else if (pid < 0) {
+         error_setg_errno(errp, errno, "failed to create child process");