git: 0c10a2255084 - stable/13 - bhyve: use linker set for ipc commands

The branch stable/13 has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=0c10a2255084711e1ddaa0f43ce1245f49194da3

commit 0c10a2255084711e1ddaa0f43ce1245f49194da3
Author:     Robert Wing <rew@FreeBSD.org>
AuthorDate: 2022-04-10 02:46:00 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2023-01-26 18:49:41 +0000

    bhyve: use linker set for ipc commands
    
    Reviewed by:    markj, jhb
    Differential Revision:  https://reviews.freebsd.org/D34760
    
    (cherry picked from commit c79331a42c308139828c1117f49224bb83617a53)
---
 usr.sbin/bhyve/ipc.h      | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 usr.sbin/bhyve/snapshot.c | 42 +++++++++++++++++++++++----------------
 2 files changed, 75 insertions(+), 17 deletions(-)

diff --git a/usr.sbin/bhyve/ipc.h b/usr.sbin/bhyve/ipc.h
new file mode 100644
index 000000000000..38faf69eb5f4
--- /dev/null
+++ b/usr.sbin/bhyve/ipc.h
@@ -0,0 +1,50 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2022 Rob Wing <rew@FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#ifndef _IPC_H_
+#define _IPC_H_
+
+#include <sys/cdefs.h>
+#include <sys/linker_set.h>
+#include <sys/nv.h>
+
+struct ipc_command {
+	char *name;
+	int (*handler)(struct vmctx *ctx, const nvlist_t *nvl);
+};
+
+#define IPC_COMMAND(set, name, function)			\
+	static struct ipc_command name ## _ipc_command =	\
+	{ #name, function };					\
+	DATA_SET(set, name ## _ipc_command);
+
+#define IPC_COMMAND_FOREACH(pvar, set)	SET_FOREACH(pvar, set)
+
+SET_DECLARE(ipc_cmd_set, struct ipc_command);
+
+#endif /* _IPC_H_ */
diff --git a/usr.sbin/bhyve/snapshot.c b/usr.sbin/bhyve/snapshot.c
index ee709147cec4..7c34a9b2f0ea 100644
--- a/usr.sbin/bhyve/snapshot.c
+++ b/usr.sbin/bhyve/snapshot.c
@@ -81,6 +81,7 @@ __FBSDID("$FreeBSD$");
 #include "atkbdc.h"
 #include "debug.h"
 #include "inout.h"
+#include "ipc.h"
 #include "fwctl.h"
 #include "ioapic.h"
 #include "mem.h"
@@ -1428,30 +1429,19 @@ done:
 static int
 handle_message(struct vmctx *ctx, nvlist_t *nvl)
 {
-	int err;
 	const char *cmd;
+	struct ipc_command **ipc_cmd;
 
 	if (!nvlist_exists_string(nvl, "cmd"))
-		return (-1);
+		return (EINVAL);
 
 	cmd = nvlist_get_string(nvl, "cmd");
-	if (strcmp(cmd, "checkpoint") == 0) {
-		if (!nvlist_exists_string(nvl, "filename") ||
-		    !nvlist_exists_bool(nvl, "suspend"))
-			err = -1;
-		else
-			err = vm_checkpoint(ctx, nvlist_get_string(nvl, "filename"),
-			    nvlist_get_bool(nvl, "suspend"));
-	} else {
-		EPRINTLN("Unrecognized checkpoint operation\n");
-		err = -1;
+	IPC_COMMAND_FOREACH(ipc_cmd, ipc_cmd_set) {
+		if (strcmp(cmd, (*ipc_cmd)->name) == 0)
+			return ((*ipc_cmd)->handler(ctx, nvl));
 	}
 
-	if (err != 0)
-		EPRINTLN("Unable to perform the requested operation\n");
-
-	nvlist_destroy(nvl);
-	return (err);
+	return (EOPNOTSUPP);
 }
 
 /*
@@ -1472,11 +1462,29 @@ checkpoint_thread(void *param)
 			handle_message(thread_info->ctx, nvl);
 		else
 			EPRINTLN("nvlist_recv() failed: %s", strerror(errno));
+
+		nvlist_destroy(nvl);
 	}
 
 	return (NULL);
 }
 
+static int
+vm_do_checkpoint(struct vmctx *ctx, const nvlist_t *nvl)
+{
+	int error;
+
+	if (!nvlist_exists_string(nvl, "filename") ||
+	    !nvlist_exists_bool(nvl, "suspend"))
+		error = EINVAL;
+	else
+		error = vm_checkpoint(ctx, nvlist_get_string(nvl, "filename"),
+		    nvlist_get_bool(nvl, "suspend"));
+
+	return (error);
+}
+IPC_COMMAND(ipc_cmd_set, checkpoint, vm_do_checkpoint);
+
 void
 init_snapshot(void)
 {