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/**
* @file initrd.c
* Initrd image support
* An archive file (made with ar) can be linked into the final executable to
* allow files to be loaded in memory on boot. See mkinitrd.sh or the Makefile
* for more info.
*
* Copyright (C) 2018 Clyne Sullivan
*
* This program 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.
*
* This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <initrd.h>
extern uint8_t _binary_initrd_img_start[];
extern uint8_t _binary_initrd_img_size[];
static const void *initrd_start = (void *)_binary_initrd_img_start;
static const uint32_t initrd_size = (uint32_t)_binary_initrd_img_size;
static const char *initrd_sig = "!<arch>\n";
uint8_t initrd_validate(void)
{
initrd_header *header = (initrd_header *)initrd_start;
for (uint8_t i = 0; i < 8; i++) {
if (header->signature[i] != initrd_sig[i])
return 0;
}
return 1;
}
uint8_t initrd_nametest(char *file, const char *want)
{
for (uint8_t i = 0; i < 16; i++) {
if (want[i] == '\0')
return (file[i] == '/');
else if (want[i] != file[i])
return 0;
}
return 0;
}
uint32_t ipow10(uint8_t n)
{
uint32_t i = 1;
while (n--)
i *= 10;
return i;
}
uint32_t initrd_getsize(initrd_file *file)
{
uint32_t size = 0;
char *p = file->size + 10;
while (*--p == ' ');
for (int8_t i = p - file->size, j = 0; i >= 0; i--, j++)
size += (*p-- - '0') * ipow10(j);
return size;
}
initrd_file *initrd_getfileptr(const char *name)
{
initrd_file *file = (initrd_file *)((uint8_t *)initrd_start + sizeof(initrd_header));
uint32_t offset = sizeof(initrd_header);
while (offset < initrd_size) {
if (initrd_nametest(file->name, name))
return file;
uint32_t size = initrd_getsize(file) + sizeof(initrd_file);
offset += size;
file = (initrd_file *)((uint8_t *)file + size + 1);
}
return 0;
}
char *initrd_getfile(const char *name)
{
initrd_file *file = initrd_getfileptr(name);
if (file == 0)
return 0;
char *ptr = (char *)file + sizeof(initrd_file);
ptr[initrd_getsize(file) - 1] = 0;
return ptr;
}
uint32_t initrd_getfilesize(const char *name)
{
initrd_file *file = initrd_getfileptr(name);
if (file == 0)
return 0;
return initrd_getsize(file);
}
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