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Save where we're booted from

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Record the file path for boot1.efi as the UEFI environemnt variable
FreeBSDBootVarGUID:Boot1Path. Record the device this came from as
FreeBSDBootVarGUID:Boot1Dev. While later stages of the boot may be
able to guess these values by retrieving UEFIGlobal:BootCurrent and
groveling through the correct UEFIGlobal:BootXXXX, this provides
certanty in the face of behavior from any part of the boot loader
chain that might "guess" what to do next. These env variables are
volatile and will disappear on reboot.

Sponsored by: Netflix
This commit is contained in:
Warner Losh 2017-08-31 17:32:24 +00:00
parent b048c3564d
commit 6b4a1e856f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=323065
2 changed files with 34 additions and 1 deletions
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33
sys/boot/efi/boot1/boot1.c
View File

@ -29,6 +29,8 @@ __FBSDID("$FreeBSD$");
#include <efi.h>
#include <eficonsctl.h>
typedef CHAR16 efi_char;
#include <efichar.h>
#include "boot_module.h"
#include "paths.h"
@ -53,6 +55,7 @@ static EFI_GUID BlockIoProtocolGUID = BLOCK_IO_PROTOCOL;
static EFI_GUID DevicePathGUID = DEVICE_PATH_PROTOCOL;
static EFI_GUID LoadedImageGUID = LOADED_IMAGE_PROTOCOL;
static EFI_GUID ConsoleControlGUID = EFI_CONSOLE_CONTROL_PROTOCOL_GUID;
static EFI_GUID FreeBSDBootVarGUID = FREEBSD_BOOT_VAR_GUID;
/*
* Provide Malloc / Free backed by EFIs AllocatePool / FreePool which ensures
@ -77,6 +80,34 @@ Free(void *buf, const char *file __unused, int line __unused)
(void)BS->FreePool(buf);
}
static int
wcslen(const CHAR16 *str)
{
int i;
i = 0;
while (*str++)
i++;
return i;
}
static EFI_STATUS
efi_setenv_freebsd_wcs(const char *varname, CHAR16 *valstr)
{
CHAR16 *var = NULL;
size_t len;
EFI_STATUS rv;
utf8_to_ucs2(varname, &var, &len);
if (var == NULL)
return (EFI_OUT_OF_RESOURCES);
rv = RS->SetVariable(var, &FreeBSDBootVarGUID,
EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
wcslen(valstr) * 2, valstr);
free(var);
return (rv);
}
/*
* devpath_last returns the last non-path end node in devpath.
*/
@ -394,6 +425,7 @@ efi_main(EFI_HANDLE Ximage, EFI_SYSTEM_TABLE *Xsystab)
if (status == EFI_SUCCESS) {
text = efi_devpath_name(img->FilePath);
printf(" Load Path: %S\n", text);
efi_setenv_freebsd_wcs("Boot1Path", text);
efi_free_devpath_name(text);
status = BS->HandleProtocol(img->DeviceHandle, &DevicePathGUID,
@ -404,6 +436,7 @@ efi_main(EFI_HANDLE Ximage, EFI_SYSTEM_TABLE *Xsystab)
} else {
text = efi_devpath_name(imgpath);
printf(" Load Device: %S\n", text);
efi_setenv_freebsd_wcs("Boot1Dev", text);
efi_free_devpath_name(text);
}

2
sys/boot/efi/include/efiapi.h
View File

@ -247,7 +247,7 @@ EFI_STATUS
typedef
EFI_STATUS
(EFIAPI *EFI_SET_VARIABLE) (
IN CHAR16 *VariableName,
IN const CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT32 Attributes,
IN UINTN DataSize,