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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <fs/initramfs.h>
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/limine.h>
#include <sys/panic.h>
#include <string.h>
__MODULE_NAME("initramfs");
__KERNEL_META("$Hyra$: initramfs.c, Ian Marco Moffett, "
"Initial ram filesystem");
static volatile struct limine_module_request mod_req = {
.id = LIMINE_MODULE_REQUEST,
.revision = 0
};
static const char *initramfs = NULL;
static size_t initramfs_size = 0;
struct tar_hdr {
char filename[100];
char mode[8];
char uid[8];
char gid[8];
char size[12];
char mtime[12];
char chksum[8];
char typeflag[1];
};
static char *
get_module(const char *path, uint64_t *size) {
for (uint64_t i = 0; i < mod_req.response->module_count; ++i) {
if (strcmp(mod_req.response->modules[i]->path, path) == 0) {
*size = mod_req.response->modules[i]->size;
return mod_req.response->modules[i]->address;
}
}
return NULL;
}
static size_t
getsize(const char *in)
{
size_t size = 0, count = 1;
for (size_t j = 11; j > 0; --j, count *= 8) {
size += (in[j-1]-'0')*count;
}
return size;
}
static int
initramfs_init(void)
{
initramfs = get_module("/boot/initramfs.tar", &initramfs_size);
if (initramfs == NULL) {
panic("Failed to load initramfs\n");
}
return 0;
}
const char *
initramfs_open(const char *path)
{
uintptr_t addr, size;
struct tar_hdr *hdr;
if (initramfs == NULL) {
initramfs_init();
}
if (strlen(path) > 99) {
return NULL;
}
addr = (uintptr_t)initramfs + 0x200;
hdr = (struct tar_hdr *)addr;
while (hdr->filename[0] != '\0') {
hdr = (struct tar_hdr *)addr;
size = getsize(hdr->size);
if (strcmp(hdr->filename, path) == 0) {
return ((char*)addr) + 0x200;
}
addr += (((size + 511) / 512) + 1) * 512;
}
return NULL;
}
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