Author: imp
Date: Mon Jun 3 19:10:46 2019
New Revision: 348569
URL: https://svnweb.freebsd.org/changeset/base/348569
Log:
[zfsboot] Fix boot env back compat (#190)
* Fix boot env back compat
zfsboot must try zfsloader before loader in order to remain compatible
with boot environments created prior to zfs functionality being rolled
into loader proper.
* Improve comments in zfsboot
Explain the significance of the load path order, and put the comment
about looping through the paths in the appropriate scope.
Obtained From: TrueNAS commit 4c60c62fcf0b6b6eac98ee8d46e7bbea64bc86f5
Submitted by: Ryan Moeller <r...@freqlabs.com>
Modified:
head/stand/common/paths.h
head/stand/i386/zfsboot/zfsboot.c
Modified: head/stand/common/paths.h
==============================================================================
--- head/stand/common/paths.h Mon Jun 3 19:09:39 2019 (r348568)
+++ head/stand/common/paths.h Mon Jun 3 19:10:46 2019 (r348569)
@@ -33,6 +33,7 @@
#define PATH_CONFIG "/boot/config"
#define PATH_LOADER "/boot/loader"
#define PATH_LOADER_EFI "/boot/loader.efi"
+#define PATH_LOADER_ZFS "/boot/zfsloader"
#define PATH_KERNEL "/boot/kernel/kernel"
#endif /* _PATHS_H_ */
Modified: head/stand/i386/zfsboot/zfsboot.c
==============================================================================
--- head/stand/i386/zfsboot/zfsboot.c Mon Jun 3 19:09:39 2019
(r348568)
+++ head/stand/i386/zfsboot/zfsboot.c Mon Jun 3 19:10:46 2019
(r348569)
@@ -87,6 +87,24 @@ static const unsigned char flags[NOPT] = {
};
uint32_t opts;
+/*
+ * Paths to try loading before falling back to the boot2 prompt.
+ *
+ * /boot/zfsloader must be tried before /boot/loader in order to remain
+ * backward compatible with ZFS boot environments where /boot/loader exists
+ * but does not have ZFS support, which was the case before FreeBSD 12.
+ *
+ * If no loader is found, try to load a kernel directly instead.
+ */
+static const struct string {
+ const char *p;
+ size_t len;
+} loadpath[] = {
+ { PATH_LOADER_ZFS, sizeof(PATH_LOADER_ZFS) },
+ { PATH_LOADER, sizeof(PATH_LOADER) },
+ { PATH_KERNEL, sizeof(PATH_KERNEL) },
+};
+
static const unsigned char dev_maj[NDEV] = {30, 4, 2};
static char cmd[512];
@@ -857,16 +875,17 @@ main(void)
if (nextboot && !autoboot)
reboot();
- /*
- * Try to exec /boot/loader. If interrupted by a keypress,
- * or in case of failure, try to load a kernel directly instead.
- */
-
if (autoboot && !*kname) {
- memcpy(kname, PATH_LOADER, sizeof(PATH_LOADER));
- if (!keyhit(3)) {
+ /*
+ * Iterate through the list of loader and kernel paths, trying to load.
+ * If interrupted by a keypress, or in case of failure, drop the user
+ * to the boot2 prompt.
+ */
+ for (i = 0; i < nitems(loadpath); i++) {
+ memcpy(kname, loadpath[i].p, loadpath[i].len);
+ if (keyhit(3))
+ break;
load();
- memcpy(kname, PATH_KERNEL, sizeof(PATH_KERNEL));
}
}
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