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/* SPDX-License-Identifier: GPL-3.0-or-later */
/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
/**
* @file initrd.c
* Handle initrd, implement cpio with newc format.
*/
#include <apos/initrd.h>
#include <apos/vmem.h>
#include <apos/string.h>
#include <apos/utils.h>
#include <apos/attrs.h>
#include <libfdt.h>
/** GNU cpio, POSIX 'newc' format header. */
struct __packed cpio_header {
/** Magic bytes. */
char c_magic[6];
/** File inode. */
char c_ino[8];
/** File type and permissions. */
char c_mode[8];
/** User ID. */
char c_uid[8];
/** Group ID. */
char c_gid[8];
/** Number of links to this file. */
char c_nlink[8];
/** Modification time. */
char c_mtime[8];
/** Size of file. */
char c_filesize[8];
/** Device major. */
char c_devmajor[8];
/** Device minor. */
char c_devminor[8];
/** Block device major. */
char c_rdevmajor[8];
/** Block device minor. */
char c_rdevminor[8];
/** Length of filename. */
char c_namesize[8];
/** CRC check. */
char c_check[8];
};
/**
* Get next file in archive.
* Does not check for out of bounds.
*
* @param cp Pointer to current file header.
* @return Pointer to next file header.
*/
static struct cpio_header *__next_entry(struct cpio_header *cp)
{
size_t blen = align_up(
sizeof(struct cpio_header) + convnum(cp->c_namesize, 8, 16), 4);
size_t tlen = align_up(convnum(cp->c_filesize, 8, 16), 4);
return (struct cpio_header *)(((char *)cp) + blen + tlen);
}
/**
* Get file with name in archive.
*
* @param c Pointer to initrd.
* @param fname Filename to look for.
* @param fname_len Length of filename.
* @return Pointer to corresponding file header if found, \c NULL otherwise.
*/
static struct cpio_header *__find_file(const char *c, const char *fname,
size_t fname_len)
{
struct cpio_header *cp = (struct cpio_header *)c;
for (; cp; cp = __next_entry(cp)) {
size_t namelen = convnum(cp->c_namesize, 8, 16);
if (namelen == 0)
return NULL;
if (namelen < fname_len)
continue;
char *name = (char *)(cp + 1);
if (fname[0] != '/')
name += namelen - (fname_len + 1); /* match ending */
if (strncmp(name, fname, fname_len) == 0)
return cp;
}
return NULL;
}
/** Name of \c init program. */
static char init_n[] = "init";
/** Length of \c init name. */
static size_t init_nlen = ARRAY_SIZE(init_n) - 1; /* ignore trailing NULL */
pm_t get_initrdtop(const void *fdt)
{
int chosen_offset = fdt_path_offset(fdt, "/chosen");
struct cell_info ci = get_cellinfo(fdt, chosen_offset);
void *initrd_end_ptr = (void *)fdt_getprop(fdt, chosen_offset,
"linux,initrd-end", NULL);
/* fdt is only aware of physical memory pointers */
return (pm_t)__va(fdt_load_int_ptr(ci.addr_cells, initrd_end_ptr));
}
pm_t get_initrdbase(const void *fdt)
{
const int chosen_offset = fdt_path_offset(fdt, "/chosen");
const struct cell_info ci = get_cellinfo(fdt, chosen_offset);
void *initrd_base_ptr = (void *)fdt_getprop(fdt, chosen_offset,
"linux,initrd-start", NULL);
return (pm_t)__va(fdt_load_int_ptr(ci.addr_cells, initrd_base_ptr));
}
size_t get_init_size(const void *fdt)
{
char *c = (char *)get_initrdbase(fdt);
struct cpio_header *cp = __find_file(c, init_n, init_nlen);
return convnum(cp->c_filesize, 8, 16);
}
vm_t get_init_base(const void *fdt)
{
char *c = (char *)get_initrdbase(fdt);
struct cpio_header *cp = __find_file(c, init_n, init_nlen);
size_t name_len = convnum(cp->c_namesize, 8, 16);
return ((vm_t)cp) + align_up(sizeof(struct cpio_header) + name_len, 4);
}
stat_t move_init(const void *fdt, void *target)
{
const char *c = (const char *)get_initrdbase(fdt);
const struct cpio_header *cp = __find_file(c, init_n, init_nlen);
size_t name_len = convnum(cp->c_namesize, 8, 16);
size_t file_len = convnum(cp->c_filesize, 8, 16);
char *fp = (char *)cp;
fp += align_up(sizeof(struct cpio_header) + name_len, 4);
memmove(target, fp, file_len);
return OK;
}
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