git: 482ab31c64cd - stable/13 - bhyveload: support guest rebooting from the loader

The branch stable/13 has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=482ab31c64cd6da8f1044eaef87212581dc4884d

commit 482ab31c64cd6da8f1044eaef87212581dc4884d
Author:     Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2024-01-05 06:21:15 +0000
Commit:     Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2024-01-22 17:17:52 +0000

    bhyveload: support guest rebooting from the loader
    
    userboot has a EXIT_REBOOT code that it uses when the 'reboot' loader
    command is executed.  Use that and longjmp back to reinit the VM
    entirely with a reboot request.  This fixes the 'reboot' option in the
    loader menu to actually reboot rather than shutdown the VM.
    
    The JMP_* constants are introduced to keep track of why we're doing a
    longjmp, though they aren't currently used.  We'll notably still do a
    complete reload of the interpreter to give the rebooted VM that new
    loader smell.  It just seemed forward thinking to just keep track of the
    different setjmp points.
    
    While we're here, we don't actually need to keep the fd we passed to
    fdlopen(3), so let's avoid leaking it.
    
    Reviewed by:    markj
    
    (cherry picked from commit 24cd5c26fe3ef7181e85467d9d55afbd76af5a2c)
---
 usr.sbin/bhyveload/bhyveload.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/bhyveload/bhyveload.c b/usr.sbin/bhyveload/bhyveload.c
index d4f282bcc178..f2a91f95ce89 100644
--- a/usr.sbin/bhyveload/bhyveload.c
+++ b/usr.sbin/bhyveload/bhyveload.c
@@ -89,6 +89,16 @@
 
 #define	NDISKS	32
 
+/*
+ * Reason for our loader reload and reentry, though these aren't really used
+ * at the moment.
+ */
+enum {
+	/* 0 cannot be allocated; setjmp(3) return. */
+	JMP_SWAPLOADER = 0x01,
+	JMP_REBOOT,
+};
+
 static struct termios term, oldterm;
 static int disk_fd[NDISKS];
 static int ndisks;
@@ -542,6 +552,8 @@ cb_exit(void *arg __unused, int v)
 {
 
 	tcsetattr(consout_fd, TCSAFLUSH, &oldterm);
+	if (v == USERBOOT_EXIT_REBOOT)
+		longjmp(jb, JMP_REBOOT);
 	exit(v);
 }
 
@@ -625,7 +637,7 @@ cb_swap_interpreter(void *arg __unused, const char *interp_req)
 
 	if (asprintf(&loader, "userboot_%s.so", interp_req) == -1)
 		err(EX_OSERR, "malloc");
-	longjmp(jb, 1);
+	longjmp(jb, JMP_SWAPLOADER);
 }
 
 static struct loader_callbacks cb = {
@@ -766,6 +778,8 @@ loader_open(int bootfd)
 	loader_hdl = fdlopen(fd, RTLD_LOCAL);
 	if (!loader_hdl)
 		errx(EX_OSERR, "dlopen: %s", dlerror());
+	if (fd != explicit_loader_fd)
+		close(fd);
 }
 
 int