git: 619d09217720 - main - iuserboot: bump the interface to v6, add an accept_interpreter callback

The branch main has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=619d09217720cb82f562b51e98576438dc11c830

commit 619d09217720cb82f562b51e98576438dc11c830
Author:     Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2026-09-04 15:26:35 +0000
Commit:     Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2026-09-04 15:26:35 +0000

    iuserboot: bump the interface to v6, add an accept_interpreter callback
    
    If an explicit loader wasn't requested, then bhyveload(8) maintains a
    /boot handle that it can use for swapping to a different flavor.  This
    means that we expose all of the host /boot to the sandbox for the
    duration of script execution.
    
    Add a callback to ack that we're OK with the interpreter so that
    bhyveload(8) can release the bootfd.  This is worth doing because it's
    prior to guest script execution, so we're still running a reasonably
    untainted process.
    
    Reviewed by:    imp, jhb
    Differential Revision:  https://reviews.freebsd.org/D58771
---
 stand/userboot/userboot.h      | 12 ++++++++++++
 stand/userboot/userboot/main.c |  2 ++
 usr.sbin/bhyveload/bhyveload.c | 23 ++++++++++++++++++-----
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/stand/userboot/userboot.h b/stand/userboot/userboot.h
index 34e8cb1d4bb2..1204f5e87f6f 100644
--- a/stand/userboot/userboot.h
+++ b/stand/userboot/userboot.h
@@ -46,6 +46,13 @@
  */
 #define	USERBOOT_VERSION_5      5
 
+/*
+ * Version 6 added a callback for indicating that the guest
+ * is OK with the existing interpreter, so the host can close associated
+ * resources.  The callback structure is still backward compatible.
+ */
+#define	USERBOOT_VERSION_6      6
+
 /*
  * Exit codes from the loader
  */
@@ -225,4 +232,9 @@ struct loader_callbacks {
 	 * Version 5 addition.
 	 */
 	void	(*swap_interpreter)(void *arg, const char *interp);
+
+	/*
+	 * Version 6 addition.
+	 */
+	void	(*accept_interpreter)(void *arg);
 };
diff --git a/stand/userboot/userboot/main.c b/stand/userboot/userboot/main.c
index 03f226c08bb9..d1f231a12e97 100644
--- a/stand/userboot/userboot/main.c
+++ b/stand/userboot/userboot/main.c
@@ -217,6 +217,8 @@ loader_main(struct loader_callbacks *cb, void *arg, int version, int ndisks)
 	 */
 	if (version >= USERBOOT_VERSION_5)
 		check_interpreter();
+	if (version >= USERBOOT_VERSION_6)
+		CALLBACK(accept_interpreter);
 
 	if (setjmp(jb))
 		return;
diff --git a/usr.sbin/bhyveload/bhyveload.c b/usr.sbin/bhyveload/bhyveload.c
index 3b416b7a5ad5..5cf05b97a00c 100644
--- a/usr.sbin/bhyveload/bhyveload.c
+++ b/usr.sbin/bhyveload/bhyveload.c
@@ -102,6 +102,7 @@ enum {
 static struct termios term, oldterm;
 static int disk_fd[NDISKS];
 static int ndisks;
+static int bootfd = -1;
 static int consin_fd, consout_fd;
 static int hostbase_fd = -1;
 
@@ -641,6 +642,16 @@ cb_swap_interpreter(void *arg __unused, const char *interp_req)
 	longjmp(jb, JMP_SWAPLOADER);
 }
 
+static void
+cb_accept_interpreter(void *arg __unused)
+{
+	if (bootfd == -1)
+		return;
+
+	close(bootfd);
+	bootfd = -1;
+}
+
 static struct loader_callbacks cb = {
 	.getc = cb_getc,
 	.putc = cb_putc,
@@ -678,6 +689,9 @@ static struct loader_callbacks cb = {
 
 	/* Version 5 additions */
 	.swap_interpreter = cb_swap_interpreter,
+
+	/* Version 6 additions */
+	.accept_interpreter = cb_accept_interpreter,
 };
 
 static int
@@ -760,7 +774,7 @@ hostbase_open(const char *base)
 }
 
 static void
-loader_open(int bootfd)
+loader_open(void)
 {
 	int fd;
 
@@ -790,9 +804,8 @@ main(int argc, char** argv)
 {
 	void (*func)(struct loader_callbacks *, void *, int, int);
 	uint64_t mem_size;
-	int bootfd, opt, error, memflags, need_reinit;
+	int opt, error, memflags, need_reinit;
 
-	bootfd = -1;
 	progname = basename(argv[0]);
 
 	memflags = 0;
@@ -922,7 +935,7 @@ main(int argc, char** argv)
 	if (error)
 		err(1, "vm_setup_memory");
 
-	loader_open(bootfd);
+	loader_open();
 	func = dlsym(loader_hdl, "loader_main");
 	if (!func)
 		errx(1, "dlsym: %s", dlerror());
@@ -937,7 +950,7 @@ main(int argc, char** argv)
 	addenv("smbios.bios.vendor=BHYVE");
 	addenv("boot_serial=1");
 
-	func(&cb, NULL, USERBOOT_VERSION_5, ndisks);
+	func(&cb, NULL, USERBOOT_VERSION_6, ndisks);
 
 	free(loader);
 	return (0);