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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
*
* initrddump.efi saves the initial RAM disk provided via the
* EFI_LOAD_FILE2_PROTOCOL.
*
* Specifying 'nocolor' as load option data suppresses colored output and
* clearing of the screen.
*/
#include <efi_api.h>
#include <efi_load_initrd.h>
#define BUFFER_SIZE 64
#define ESC 0x17
#define efi_size_in_pages(size) (((size) + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT)
static struct efi_system_table *systable;
static struct efi_boot_services *bs;
static struct efi_simple_text_output_protocol *cerr;
static struct efi_simple_text_output_protocol *cout;
static struct efi_simple_text_input_protocol *cin;
static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
static const efi_guid_t guid_simple_file_system_protocol =
EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
static const efi_guid_t load_file2_guid = EFI_LOAD_FILE2_PROTOCOL_GUID;
static efi_handle_t handle;
static bool nocolor;
/*
* Device path defined by Linux to identify the handle providing the
* EFI_LOAD_FILE2_PROTOCOL used for loading the initial ramdisk.
*/
static const struct efi_initrd_dp initrd_dp = {
.vendor = {
{
DEVICE_PATH_TYPE_MEDIA_DEVICE,
DEVICE_PATH_SUB_TYPE_VENDOR_PATH,
sizeof(initrd_dp.vendor),
},
EFI_INITRD_MEDIA_GUID,
},
.end = {
DEVICE_PATH_TYPE_END,
DEVICE_PATH_SUB_TYPE_END,
sizeof(initrd_dp.end),
}
};
/**
* color() - set foreground color
*
* @color: foreground color
*/
static void color(u8 color)
{
if (!nocolor)
cout->set_attribute(cout, color | EFI_BACKGROUND_BLACK);
}
/**
* print() - print string
*
* @string: text
*/
static void print(u16 *string)
{
cout->output_string(cout, string);
}
/**
* cls() - clear screen
*/
static void cls(void)
{
if (nocolor)
print(u"\r\n");
else
cout->clear_screen(cout);
}
/**
* error() - print error string
*
* @string: error text
*/
static void error(u16 *string)
{
color(EFI_LIGHTRED);
print(string);
color(EFI_LIGHTBLUE);
}
/*
* printx() - print hexadecimal number
*
* @val: value to print;
* @prec: minimum number of digits to print
*/
static void printx(u64 val, u32 prec)
{
int i;
u16 c;
u16 buf[16];
u16 *pos = buf;
for (i = 2 * sizeof(val) - 1; i >= 0; --i) {
c = (val >> (4 * i)) & 0x0f;
if (c || pos != buf || !i || i < prec) {
c += '0';
if (c > '9')
c += 'a' - '9' - 1;
*pos++ = c;
}
}
*pos = 0;
print(buf);
}
/**
* efi_drain_input() - drain console input
*/
static void efi_drain_input(void)
{
cin->reset(cin, true);
}
/**
* efi_input_yn() - get answer to yes/no question
*
* Return:
* y or Y
* EFI_SUCCESS
* n or N
* EFI_ACCESS_DENIED
* ESC
* EFI_ABORTED
*/
static efi_status_t efi_input_yn(void)
{
struct efi_input_key key = {0};
efi_uintn_t index;
efi_status_t ret;
for (;;) {
ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
if (ret != EFI_SUCCESS)
continue;
ret = cin->read_key_stroke(cin, &key);
if (ret != EFI_SUCCESS)
continue;
switch (key.scan_code) {
case 0x17: /* Escape */
return EFI_ABORTED;
default:
break;
}
/* Convert to lower case */
switch (key.unicode_char | 0x20) {
case 'y':
return EFI_SUCCESS;
case 'n':
return EFI_ACCESS_DENIED;
default:
break;
}
}
}
/**
* efi_input() - read string from console
*
* @buffer: input buffer
* @buffer_size: buffer size
* Return: status code
*/
static efi_status_t efi_input(u16 *buffer, efi_uintn_t buffer_size)
{
struct efi_input_key key = {0};
efi_uintn_t index;
efi_uintn_t pos = 0;
u16 outbuf[2] = u" ";
efi_status_t ret;
*buffer = 0;
for (;;) {
ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
if (ret != EFI_SUCCESS)
continue;
ret = cin->read_key_stroke(cin, &key);
if (ret != EFI_SUCCESS)
continue;
switch (key.scan_code) {
case 0x17: /* Escape */
print(u"\r\nAborted\r\n");
return EFI_ABORTED;
default:
break;
}
switch (key.unicode_char) {
case 0x08: /* Backspace */
if (pos) {
buffer[pos--] = 0;
print(u"\b \b");
}
break;
case 0x0a: /* Linefeed */
case 0x0d: /* Carriage return */
print(u"\r\n");
return EFI_SUCCESS;
default:
break;
}
/* Ignore surrogate codes */
if (key.unicode_char >= 0xD800 && key.unicode_char <= 0xDBFF)
continue;
if (key.unicode_char >= 0x20 &&
pos < buffer_size - 1) {
*outbuf = key.unicode_char;
buffer[pos++] = key.unicode_char;
buffer[pos] = 0;
print(outbuf);
}
}
}
/**
* skip_whitespace() - skip over leading whitespace
*
* @pos: UTF-16 string
* Return: pointer to first non-whitespace
*/
static u16 *skip_whitespace(u16 *pos)
{
for (; *pos && *pos <= 0x20; ++pos)
;
return pos;
}
/**
* starts_with() - check if @string starts with @keyword
*
* @string: string to search for keyword
* @keyword: keyword to be searched
* Return: true if @string starts with the keyword
*/
static bool starts_with(u16 *string, u16 *keyword)
{
if (!string || !keyword)
return false;
for (; *keyword; ++string, ++keyword) {
if (*string != *keyword)
return false;
}
return true;
}
/**
* do_help() - print help
*/
static void do_help(void)
{
error(u"load - show length and CRC32 of initial RAM disk\r\n");
error(u"save <initrd> - save initial RAM disk to file\r\n");
error(u"exit - exit the shell\r\n");
}
/**
* get_initrd() - read initial RAM disk via EFI_LOAD_FILE2_PROTOCOL
*
* @initrd: on return buffer with initial RAM disk
* @initrd_size: size of initial RAM disk
* Return: status code
*/
static efi_status_t get_initrd(void **initrd, efi_uintn_t *initrd_size)
{
struct efi_device_path *dp = (struct efi_device_path *)&initrd_dp;
struct efi_load_file_protocol *load_file2_prot;
u64 buffer;
efi_handle_t handle;
efi_status_t ret;
*initrd = NULL;
*initrd_size = 0;
ret = bs->locate_device_path(&load_file2_guid, &dp, &handle);
if (ret != EFI_SUCCESS) {
error(u"Load File2 protocol not found\r\n");
return ret;
}
ret = bs->open_protocol(handle, &load_file2_guid,
(void **)&load_file2_prot, NULL, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL);
ret = load_file2_prot->load_file(load_file2_prot, dp, false,
initrd_size, NULL);
if (ret != EFI_BUFFER_TOO_SMALL) {
error(u"Load File2 protocol does not provide file length\r\n");
return EFI_LOAD_ERROR;
}
ret = bs->allocate_pages(EFI_ALLOCATE_ANY_PAGES, EFI_LOADER_DATA,
efi_size_in_pages(*initrd_size), &buffer);
if (ret != EFI_SUCCESS) {
error(u"Out of memory\r\n");
return ret;
}
*initrd = (void *)(uintptr_t)buffer;
ret = load_file2_prot->load_file(load_file2_prot, dp, false,
initrd_size, *initrd);
if (ret != EFI_SUCCESS) {
error(u"Load File2 protocol failed to provide file\r\n");
bs->free_pages(buffer, efi_size_in_pages(*initrd_size));
return EFI_LOAD_ERROR;
}
return ret;
}
/**
* do_load() - load initial RAM disk and display CRC32 and length
*
* @filename: file name
* Return: status code
*/
static efi_status_t do_load(void)
{
void *initrd;
efi_uintn_t initrd_size;
u32 crc32;
efi_uintn_t ret;
ret = get_initrd(&initrd, &initrd_size);
if (ret != EFI_SUCCESS)
return ret;
print(u"length: 0x");
printx(initrd_size, 1);
print(u"\r\n");
ret = bs->calculate_crc32(initrd, initrd_size, &crc32);
if (ret != EFI_SUCCESS) {
error(u"Calculating CRC32 failed\r\n");
return EFI_LOAD_ERROR;
}
print(u"crc32: 0x");
printx(crc32, 8);
print(u"\r\n");
return EFI_SUCCESS;
}
/**
* do_save() - save initial RAM disk
*
* @filename: file name
* Return: status code
*/
static efi_status_t do_save(u16 *filename)
{
struct efi_loaded_image *loaded_image;
struct efi_simple_file_system_protocol *file_system;
struct efi_file_handle *root, *file;
void *initrd;
efi_uintn_t initrd_size;
efi_uintn_t ret;
ret = get_initrd(&initrd, &initrd_size);
if (ret != EFI_SUCCESS)
return ret;
filename = skip_whitespace(filename);
ret = bs->open_protocol(handle, &loaded_image_guid,
(void **)&loaded_image, NULL, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL);
if (ret != EFI_SUCCESS) {
error(u"Loaded image protocol not found\r\n");
goto out;
}
/* Open the simple file system protocol */
ret = bs->open_protocol(loaded_image->device_handle,
&guid_simple_file_system_protocol,
(void **)&file_system, NULL, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL);
if (ret != EFI_SUCCESS) {
error(u"Failed to open simple file system protocol\r\n");
goto out;
}
/* Open volume */
ret = file_system->open_volume(file_system, &root);
if (ret != EFI_SUCCESS) {
error(u"Failed to open volume\r\n");
goto out;
}
/* Check if file already exists */
ret = root->open(root, &file, filename, EFI_FILE_MODE_READ, 0);
if (ret == EFI_SUCCESS) {
file->close(file);
efi_drain_input();
print(u"Overwrite existing file (y/n)? ");
ret = efi_input_yn();
print(u"\r\n");
if (ret != EFI_SUCCESS) {
root->close(root);
error(u"Aborted by user\r\n");
goto out;
}
}
/* Create file */
ret = root->open(root, &file, filename,
EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE |
EFI_FILE_MODE_CREATE, EFI_FILE_ARCHIVE);
if (ret == EFI_SUCCESS) {
/* Write file */
ret = file->write(file, &initrd_size, initrd);
if (ret != EFI_SUCCESS) {
error(u"Failed to write file\r\n");
} else {
print(filename);
print(u" written\r\n");
}
file->close(file);
} else {
error(u"Failed to open file\r\n");
}
root->close(root);
out:
if (initrd)
bs->free_pages((uintptr_t)initrd,
efi_size_in_pages(initrd_size));
return ret;
}
/**
* get_load_options() - get load options
*
* Return: load options or NULL
*/
static u16 *get_load_options(void)
{
efi_status_t ret;
struct efi_loaded_image *loaded_image;
ret = bs->open_protocol(handle, &loaded_image_guid,
(void **)&loaded_image, NULL, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL);
if (ret != EFI_SUCCESS) {
error(u"Loaded image protocol not found\r\n");
return NULL;
}
if (!loaded_image->load_options_size || !loaded_image->load_options)
return NULL;
return loaded_image->load_options;
}
/**
* efi_main() - entry point of the EFI application.
*
* @handle: handle of the loaded image
* @systab: system table
* Return: status code
*/
efi_status_t EFIAPI efi_main(efi_handle_t image_handle,
struct efi_system_table *systab)
{
u16 *load_options;
handle = image_handle;
systable = systab;
cerr = systable->std_err;
cout = systable->con_out;
cin = systable->con_in;
bs = systable->boottime;
load_options = get_load_options();
if (starts_with(load_options, u"nocolor"))
nocolor = true;
color(EFI_WHITE);
cls();
print(u"INITRD Dump\r\n===========\r\n\r\n");
color(EFI_LIGHTBLUE);
for (;;) {
u16 command[BUFFER_SIZE];
u16 *pos;
efi_uintn_t ret;
efi_drain_input();
print(u"=> ");
ret = efi_input(command, sizeof(command));
if (ret == EFI_ABORTED)
break;
pos = skip_whitespace(command);
if (starts_with(pos, u"exit"))
break;
else if (starts_with(pos, u"load"))
do_load();
else if (starts_with(pos, u"save "))
do_save(pos + 5);
else
do_help();
}
color(EFI_LIGHTGRAY);
cls();
return EFI_SUCCESS;
}
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