I like it in general however I had a comment: in future GRUB could be able to do the same through second approach: load a constructed kexec blob with all the parts. This would allow to e.g. kexec FreeBSD. This didn't have to be implemented now. Meanwhile can we use "kexec" as command name? It's fine to have aliases "linux" and co, just let's have a command line that won't be broken if second approach becomes a reality
From: Raymund Will <rw@suse.com>
The GRUB emulator is used as a debugging utility but it could also be used
as a user-space bootloader if there is support to boot an operating system.
The Linux kernel is already able to (re)boot another kernel via the kexec
boot mechanism. So the grub-emu tool could rely on this feature and have
linux and initrd commands that are used to pass a kernel, initramfs image
and command line parameters to kexec for booting a selected menu entry.
By default the systemctl kexec option is used so systemd can shutdown all
of the running services before doing a reboot using kexec. But if this is
not present, it fallbacks to executing the kexec user-space tool directly.
Signed-off-by: Raymund Will <rw@suse.com>
Signed-off-by: John Jolly <jjolly@suse.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
grub-core/Makefile.am | 1 +
grub-core/Makefile.core.def | 2 +-
grub-core/kern/emu/main.c | 4 +
grub-core/kern/emu/misc.c | 18 +++-
grub-core/loader/emu/linux.c | 182 +++++++++++++++++++++++++++++++++++
include/grub/emu/exec.h | 4 +-
include/grub/emu/hostfile.h | 3 +-
include/grub/emu/misc.h | 3 +
8 files changed, 213 insertions(+), 4 deletions(-)
create mode 100644 grub-core/loader/emu/linux.c
diff --git a/grub-core/Makefile.am b/grub-core/Makefile.am
index ee88e44e97..80e7a83edf 100644
--- a/grub-core/Makefile.am
+++ b/grub-core/Makefile.am
@@ -307,6 +307,7 @@ KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/emu/net.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/emu/hostdisk.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/emu/hostfile.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/extcmd.h
+KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/emu/exec.h
if COND_GRUB_EMU_SDL
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/sdl.h
endif
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 7159948721..5350408601 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1816,9 +1816,9 @@ module = {
arm64 = loader/arm64/linux.c;
riscv32 = loader/riscv/linux.c;
riscv64 = loader/riscv/linux.c;
+ emu = loader/emu/linux.c;
common = loader/linux.c;
common = lib/cmdline.c;
- enable = noemu;
};
module = {
diff --git a/grub-core/kern/emu/main.c b/grub-core/kern/emu/main.c
index 44e087e988..b4da9d21cf 100644
--- a/grub-core/kern/emu/main.c
+++ b/grub-core/kern/emu/main.c
@@ -107,6 +107,7 @@ static struct argp_option options[] = {
N_("use GRUB files in the directory DIR [default=%s]"), 0},
{"verbose", 'v', 0, 0, N_("print verbose messages."), 0},
{"hold", 'H', N_("SECS"), OPTION_ARG_OPTIONAL, N_("wait until a debugger will attach"), 0},
+ {"kexec", 'X', 0, 0, N_("use kexec to boot Linux kernels."), 0},
{ 0, 0, 0, 0, 0, 0 }
};
@@ -164,6 +165,9 @@ argp_parser (int key, char *arg, struct argp_state *state)
case 'v':
verbosity++;
break;
+ case 'X':
+ grub_util_set_kexecute ();
+ break;
case ARGP_KEY_ARG:
{
diff --git a/grub-core/kern/emu/misc.c b/grub-core/kern/emu/misc.c
index d0e7a107e7..521220b49d 100644
--- a/grub-core/kern/emu/misc.c
+++ b/grub-core/kern/emu/misc.c
@@ -39,6 +39,7 @@
#include <grub/emu/misc.h>
int verbosity;
+int kexecute;
void
grub_util_warn (const char *fmt, ...)
@@ -82,7 +83,7 @@ grub_util_error (const char *fmt, ...)
vfprintf (stderr, fmt, ap);
va_end (ap);
fprintf (stderr, ".\n");
- exit (1);
+ grub_exit ();
}
void *
@@ -153,6 +154,9 @@ xasprintf (const char *fmt, ...)
void
grub_exit (void)
{
+#if defined (GRUB_KERNEL)
+ grub_reboot ();
+#endif
exit (1);
}
#endif
@@ -214,3 +218,15 @@ grub_util_load_image (const char *path, char *buf)
fclose (fp);
}
+
+void
+grub_util_set_kexecute (void)
+{
+ kexecute++;
+}
+
+int
+grub_util_get_kexecute (void)
+{
+ return kexecute;
+}
diff --git a/grub-core/loader/emu/linux.c b/grub-core/loader/emu/linux.c
new file mode 100644
index 0000000000..020cf56cd1
--- /dev/null
+++ b/grub-core/loader/emu/linux.c
@@ -0,0 +1,182 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2006,2007,2008,2009,2010 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/loader.h>
+#include <grub/dl.h>
+#include <grub/command.h>
+#include <grub/time.h>
+
+#include <grub/emu/exec.h>
+#include <grub/emu/hostfile.h>
+#include <grub/emu/misc.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_dl_t my_mod;
+
+static char *kernel_path;
+static char *initrd_path;
+static char *boot_cmdline;
+
+static grub_err_t
+grub_linux_boot (void)
+{
+ grub_err_t rc = GRUB_ERR_NONE;
+ char *initrd_param;
+ const char *kexec[] = { "kexec", "-l", kernel_path, boot_cmdline, NULL, NULL };
+ const char *systemctl[] = { "systemctl", "kexec", NULL };
+ int kexecute = grub_util_get_kexecute ();
+
+ if (initrd_path)
+ {
+ initrd_param = grub_xasprintf ("--initrd=%s", initrd_path);
+ kexec[3] = initrd_param;
+ kexec[4] = boot_cmdline;
+ }
+ else
+ {
+ initrd_param = grub_xasprintf ("%s", "");
+ }
+
+ grub_dprintf ("linux", "%serforming 'kexec -l %s %s %s'\n",
+ (kexecute) ? "P" : "Not p",
+ kernel_path, initrd_param, boot_cmdline);
+
+ if (kexecute)
+ rc = grub_util_exec (kexec);
+
+ grub_free(initrd_param);
+
+ if (rc != GRUB_ERR_NONE)
+ {
+ grub_error (rc, N_("Error trying to perform kexec load operation."));
+ grub_sleep (3);
+ return rc;
+ }
+
+ if (kexecute < 1)
+ grub_fatal (N_("Use '"PACKAGE"-emu --kexec' to force a system restart."));
+
+ grub_dprintf ("linux", "Performing 'systemctl kexec' (%s) ",
+ (kexecute==1) ? "do-or-die" : "just-in-case");
+ rc = grub_util_exec (systemctl);
+
+ if (rc == GRUB_ERR_NONE)
+ return rc;
+
+ grub_error (rc, N_("Error trying to perform 'systemctl kexec'"));
+
+ /* need to check read-only root before resetting hard!? */
+ grub_dprintf ("linux", "Performing 'kexec -e -x'");
+ kexec[1] = "-e";
+ kexec[2] = "-x";
+ kexec[3] = NULL;
+ rc = grub_util_exec (kexec);
+ if ( rc != GRUB_ERR_NONE )
+ grub_fatal (N_("Error trying to directly perform 'kexec -e'."));
+
+ return rc;
+}
+
+static grub_err_t
+grub_linux_unload (void)
+{
+ grub_dl_unref (my_mod);
+ if ( boot_cmdline != NULL )
+ grub_free (boot_cmdline);
+ boot_cmdline = NULL;
+ return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)), int argc, char *argv[])
+{
+ int i;
+ char *tempstr;
+
+ grub_dl_ref (my_mod);
+
+ if (argc == 0)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
+
+ if ( !grub_util_is_regular (argv[0]) )
+ return grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("Cannot find kernel file %s"), argv[0]);
+
+ if ( kernel_path != NULL )
+ grub_free (kernel_path);
+
+ kernel_path = grub_xasprintf ("%s", argv[0]);
+
+ if ( boot_cmdline != NULL )
+ {
+ grub_free(boot_cmdline);
+ boot_cmdline = NULL;
+ }
+
+ if ( argc > 1 )
+ {
+ boot_cmdline = grub_xasprintf("--command-line=%s", argv[1]);
+ for ( i = 2; i < argc; i++ )
+ {
+ tempstr = grub_xasprintf("%s %s", boot_cmdline, argv[i]);
+ grub_free(boot_cmdline);
+ boot_cmdline = tempstr;
+ }
+ }
+
+ grub_loader_set (grub_linux_boot, grub_linux_unload, 0);
+
+ return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)), int argc, char *argv[])
+{
+ if (argc == 0)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
+
+ if ( !grub_util_is_regular (argv[0]) )
+ return grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("Cannot find initrd file %s"), argv[0]);
+
+ if ( initrd_path != NULL )
+ grub_free (initrd_path);
+
+ initrd_path = grub_xasprintf("%s", argv[0]);
+
+ grub_dl_unref (my_mod);
+
+ return GRUB_ERR_NONE;
+}
+
+static grub_command_t cmd_linux, cmd_initrd;
+
+GRUB_MOD_INIT (linux)
+{
+ cmd_linux = grub_register_command ("linux", grub_cmd_linux, 0, N_("Load Linux."));
+ cmd_initrd = grub_register_command ("initrd", grub_cmd_initrd, 0, N_("Load initrd."));
+ my_mod = mod;
+ kernel_path = NULL;
+ initrd_path = NULL;
+ boot_cmdline = NULL;
+}
+
+GRUB_MOD_FINI (linux)
+{
+ grub_unregister_command (cmd_linux);
+ grub_unregister_command (cmd_initrd);
+}
diff --git a/include/grub/emu/exec.h b/include/grub/emu/exec.h
index d1073ef86a..1b61b4a2e5 100644
--- a/include/grub/emu/exec.h
+++ b/include/grub/emu/exec.h
@@ -23,6 +23,8 @@
#include <stdarg.h>
#include <sys/types.h>
+#include <grub/symbol.h>
+
pid_t
grub_util_exec_pipe (const char *const *argv, int *fd);
pid_t
@@ -32,7 +34,7 @@ int
grub_util_exec_redirect_all (const char *const *argv, const char *stdin_file,
const char *stdout_file, const char *stderr_file);
int
-grub_util_exec (const char *const *argv);
+EXPORT_FUNC(grub_util_exec) (const char *const *argv);
int
grub_util_exec_redirect (const char *const *argv, const char *stdin_file,
const char *stdout_file);
diff --git a/include/grub/emu/hostfile.h b/include/grub/emu/hostfile.h
index cfb1e2b566..a61568e36e 100644
--- a/include/grub/emu/hostfile.h
+++ b/include/grub/emu/hostfile.h
@@ -22,6 +22,7 @@
#include <grub/disk.h>
#include <grub/partition.h>
#include <sys/types.h>
+#include <grub/symbol.h>
#include <grub/osdep/hostfile.h>
int
@@ -29,7 +30,7 @@ grub_util_is_directory (const char *path);
int
grub_util_is_special_file (const char *path);
int
-grub_util_is_regular (const char *path);
+EXPORT_FUNC(grub_util_is_regular) (const char *path);
char *
grub_util_path_concat (size_t n, ...);
diff --git a/include/grub/emu/misc.h b/include/grub/emu/misc.h
index ff9c48a649..01056954b9 100644
--- a/include/grub/emu/misc.h
+++ b/include/grub/emu/misc.h
@@ -57,6 +57,9 @@ void EXPORT_FUNC(grub_util_warn) (const char *fmt, ...) __attribute__ ((format (
void EXPORT_FUNC(grub_util_info) (const char *fmt, ...) __attribute__ ((format (GNU_PRINTF, 1, 2)));
void EXPORT_FUNC(grub_util_error) (const char *fmt, ...) __attribute__ ((format (GNU_PRINTF, 1, 2), noreturn));
+void EXPORT_FUNC(grub_util_set_kexecute) (void);
+int EXPORT_FUNC(grub_util_get_kexecute) (void) WARN_UNUSED_RESULT;
+
grub_uint64_t EXPORT_FUNC (grub_util_get_cpu_time_ms) (void);
#ifdef HAVE_DEVICE_MAPPER
--
2.35.1
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