u-boot/lib/efi_loader/efi_bootmgr.c
Heinrich Schuchardt 72fa9cd59e efi_loader: create boot options without file path
Allow the efidebug command to create boot options without file path, e.g.

    efidebug boot add -b 0001 'short dev only' host 0:1 ''
    efidebug boot add -B 0002 'long dev only' host 0:1 ''

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2022-06-12 13:02:34 +02:00

342 lines
8.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* EFI boot manager
*
* Copyright (c) 2017 Rob Clark
*/
#define LOG_CATEGORY LOGC_EFI
#include <common.h>
#include <charset.h>
#include <log.h>
#include <malloc.h>
#include <efi_default_filename.h>
#include <efi_loader.h>
#include <efi_variable.h>
#include <asm/unaligned.h>
static const struct efi_boot_services *bs;
static const struct efi_runtime_services *rs;
/*
* bootmgr implements the logic of trying to find a payload to boot
* based on the BootOrder + BootXXXX variables, and then loading it.
*
* TODO detecting a special key held (f9?) and displaying a boot menu
* like you would get on a PC would be clever.
*
* TODO if we had a way to write and persist variables after the OS
* has started, we'd also want to check OsIndications to see if we
* should do normal or recovery boot.
*/
/**
* expand_media_path() - expand a device path for default file name
* @device_path: device path to check against
*
* If @device_path is a media or disk partition which houses a file
* system, this function returns a full device path which contains
* an architecture-specific default file name for removable media.
*
* Return: a newly allocated device path
*/
static
struct efi_device_path *expand_media_path(struct efi_device_path *device_path)
{
struct efi_device_path *dp, *rem, *full_path;
efi_handle_t handle;
if (!device_path)
return NULL;
/*
* If device_path is a (removable) media or partition which provides
* simple file system protocol, append a default file name to support
* booting from removable media.
*/
dp = device_path;
handle = efi_dp_find_obj(dp, &efi_simple_file_system_protocol_guid,
&rem);
if (handle) {
if (rem->type == DEVICE_PATH_TYPE_END) {
dp = efi_dp_from_file(NULL, 0,
"/EFI/BOOT/" BOOTEFI_NAME);
full_path = efi_dp_append(device_path, dp);
efi_free_pool(dp);
} else {
full_path = efi_dp_dup(device_path);
}
} else {
full_path = efi_dp_dup(device_path);
}
return full_path;
}
/**
* try_load_from_file_path() - try to load a file
*
* Given a file media path iterate through a list of handles and try to
* to load the file from each of them until the first success.
*
* @fs_handles: array of handles with the simple file protocol
* @num: number of handles in fs_handles
* @fp: file path to open
* @handle: on return pointer to handle for loaded image
* @removable: if true only consider removable media, else only non-removable
*/
static efi_status_t try_load_from_file_path(efi_handle_t *fs_handles,
efi_uintn_t num,
struct efi_device_path *fp,
efi_handle_t *handle,
bool removable)
{
struct efi_handler *handler;
struct efi_device_path *dp;
int i;
efi_status_t ret;
for (i = 0; i < num; i++) {
if (removable != efi_disk_is_removable(fs_handles[i]))
continue;
ret = efi_search_protocol(fs_handles[i], &efi_guid_device_path,
&handler);
if (ret != EFI_SUCCESS)
continue;
dp = handler->protocol_interface;
if (!dp)
continue;
dp = efi_dp_append(dp, fp);
if (!dp)
continue;
ret = EFI_CALL(efi_load_image(true, efi_root, dp, NULL, 0,
handle));
efi_free_pool(dp);
if (ret == EFI_SUCCESS)
return ret;
}
return EFI_NOT_FOUND;
}
/**
* try_load_from_short_path
* @fp: file path
* @handle: pointer to handle for newly installed image
*
* Enumerate all the devices which support file system operations,
* prepend its media device path to the file path, @fp, and
* try to load the file.
* This function should be called when handling a short-form path
* which is starting with a file device path.
*
* Return: status code
*/
static efi_status_t try_load_from_short_path(struct efi_device_path *fp,
efi_handle_t *handle)
{
efi_handle_t *fs_handles;
efi_uintn_t num;
efi_status_t ret;
ret = EFI_CALL(efi_locate_handle_buffer(
BY_PROTOCOL,
&efi_simple_file_system_protocol_guid,
NULL,
&num, &fs_handles));
if (ret != EFI_SUCCESS)
return ret;
if (!num)
return EFI_NOT_FOUND;
/* removable media first */
ret = try_load_from_file_path(fs_handles, num, fp, handle, true);
if (ret == EFI_SUCCESS)
goto out;
/* fixed media */
ret = try_load_from_file_path(fs_handles, num, fp, handle, false);
if (ret == EFI_SUCCESS)
goto out;
out:
return ret;
}
/**
* try_load_entry() - try to load image for boot option
*
* Attempt to load load-option number 'n', returning device_path and file_path
* if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
* and that the specified file to boot exists.
*
* @n: number of the boot option, e.g. 0x0a13 for Boot0A13
* @handle: on return handle for the newly installed image
* @load_options: load options set on the loaded image protocol
* Return: status code
*/
static efi_status_t try_load_entry(u16 n, efi_handle_t *handle,
void **load_options)
{
struct efi_load_option lo;
u16 varname[9];
void *load_option;
efi_uintn_t size;
efi_status_t ret;
efi_create_indexed_name(varname, sizeof(varname), "Boot", n);
load_option = efi_get_var(varname, &efi_global_variable_guid, &size);
if (!load_option)
return EFI_LOAD_ERROR;
ret = efi_deserialize_load_option(&lo, load_option, &size);
if (ret != EFI_SUCCESS) {
log_warning("Invalid load option for %ls\n", varname);
goto error;
}
if (lo.attributes & LOAD_OPTION_ACTIVE) {
struct efi_device_path *file_path;
u32 attributes;
log_debug("trying to load \"%ls\" from %pD\n", lo.label,
lo.file_path);
if (EFI_DP_TYPE(lo.file_path, MEDIA_DEVICE, FILE_PATH)) {
/* file_path doesn't contain a device path */
ret = try_load_from_short_path(lo.file_path, handle);
} else {
file_path = expand_media_path(lo.file_path);
ret = EFI_CALL(efi_load_image(true, efi_root, file_path,
NULL, 0, handle));
efi_free_pool(file_path);
}
if (ret != EFI_SUCCESS) {
log_warning("Loading %ls '%ls' failed\n",
varname, lo.label);
goto error;
}
attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS;
ret = efi_set_variable_int(u"BootCurrent",
&efi_global_variable_guid,
attributes, sizeof(n), &n, false);
if (ret != EFI_SUCCESS)
goto unload;
/* try to register load file2 for initrd's */
if (IS_ENABLED(CONFIG_EFI_LOAD_FILE2_INITRD)) {
ret = efi_initrd_register();
if (ret != EFI_SUCCESS)
goto unload;
}
log_info("Booting: %ls\n", lo.label);
} else {
ret = EFI_LOAD_ERROR;
}
/* Set load options */
if (size) {
*load_options = malloc(size);
if (!*load_options) {
ret = EFI_OUT_OF_RESOURCES;
goto error;
}
memcpy(*load_options, lo.optional_data, size);
ret = efi_set_load_options(*handle, size, *load_options);
} else {
*load_options = NULL;
}
error:
free(load_option);
return ret;
unload:
if (EFI_CALL(efi_unload_image(*handle)) != EFI_SUCCESS)
log_err("Unloading image failed\n");
free(load_option);
return ret;
}
/**
* efi_bootmgr_load() - try to load from BootNext or BootOrder
*
* Attempt to load from BootNext or in the order specified by BootOrder
* EFI variable, the available load-options, finding and returning
* the first one that can be loaded successfully.
*
* @handle: on return handle for the newly installed image
* @load_options: load options set on the loaded image protocol
* Return: status code
*/
efi_status_t efi_bootmgr_load(efi_handle_t *handle, void **load_options)
{
u16 bootnext, *bootorder;
efi_uintn_t size;
int i, num;
efi_status_t ret;
bs = systab.boottime;
rs = systab.runtime;
/* BootNext */
size = sizeof(bootnext);
ret = efi_get_variable_int(u"BootNext",
&efi_global_variable_guid,
NULL, &size, &bootnext, NULL);
if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
/* BootNext does exist here */
if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
log_err("BootNext must be 16-bit integer\n");
/* delete BootNext */
ret = efi_set_variable_int(u"BootNext",
&efi_global_variable_guid,
0, 0, NULL, false);
/* load BootNext */
if (ret == EFI_SUCCESS) {
if (size == sizeof(u16)) {
ret = try_load_entry(bootnext, handle,
load_options);
if (ret == EFI_SUCCESS)
return ret;
log_warning(
"Loading from BootNext failed, falling back to BootOrder\n");
}
} else {
log_err("Deleting BootNext failed\n");
}
}
/* BootOrder */
bootorder = efi_get_var(u"BootOrder", &efi_global_variable_guid, &size);
if (!bootorder) {
log_info("BootOrder not defined\n");
ret = EFI_NOT_FOUND;
goto error;
}
num = size / sizeof(uint16_t);
for (i = 0; i < num; i++) {
log_debug("trying to load Boot%04X\n", bootorder[i]);
ret = try_load_entry(bootorder[i], handle, load_options);
if (ret == EFI_SUCCESS)
break;
}
free(bootorder);
error:
return ret;
}