109 lines
2.5 KiB
C
109 lines
2.5 KiB
C
#include "initrd.h"
|
|
#include "string.h"
|
|
#include "console.h"
|
|
|
|
typedef struct UstarHeader {
|
|
char name[100];
|
|
char mode[8];
|
|
char uid[8];
|
|
char gid[8];
|
|
char size[12];
|
|
char mtime[12];
|
|
char checksum[8];
|
|
char typeflag;
|
|
char linkname[100];
|
|
char magic[6];
|
|
char version[2];
|
|
char uname[32];
|
|
char gname[32];
|
|
char devmajor[8];
|
|
char devminor[8];
|
|
char prefix[155];
|
|
char padding[12];
|
|
} __attribute__((packed)) UstarHeader;
|
|
|
|
static const uint8* archiveBase;
|
|
static const uint8* archiveLimit;
|
|
|
|
static uint64 parseOctal(const char* field, uint32 length)
|
|
{
|
|
uint64 value = 0;
|
|
uint32 i = 0;
|
|
while (i < length && (field[i] == ' ' || field[i] == 0))
|
|
i++;
|
|
while (i < length && field[i] >= '0' && field[i] <= '7') {
|
|
value = (value << 3) | (uint64)(field[i] - '0');
|
|
i++;
|
|
}
|
|
return value;
|
|
}
|
|
|
|
static bool validMagic(const UstarHeader* header)
|
|
{
|
|
return header->magic[0] == 'u' && header->magic[1] == 's' &&
|
|
header->magic[2] == 't' && header->magic[3] == 'a' &&
|
|
header->magic[4] == 'r';
|
|
}
|
|
|
|
void initrdInit(uint64 start, uint64 end)
|
|
{
|
|
archiveBase = (const uint8*)start;
|
|
archiveLimit = (const uint8*)end;
|
|
|
|
if (end <= start || (end - start) < 512) {
|
|
archiveBase = nullptr;
|
|
archiveLimit = nullptr;
|
|
kprintf("[ustar] module too small or missing\n");
|
|
return;
|
|
}
|
|
kprintf("[ustar] archive at %p-%p (%lu KiB)\n",
|
|
(void*)start, (void*)end, (end - start) / 1024);
|
|
}
|
|
|
|
static bool walk(uint32 wanted, UstarEntry* out, uint32* total)
|
|
{
|
|
if (!archiveBase)
|
|
return false;
|
|
|
|
const uint8* cursor = archiveBase;
|
|
uint32 index = 0;
|
|
|
|
while (cursor + 512 <= archiveLimit) {
|
|
const UstarHeader* header = (const UstarHeader*)cursor;
|
|
if (header->name[0] == 0)
|
|
break;
|
|
if (!validMagic(header))
|
|
break;
|
|
|
|
uint64 size = parseOctal(header->size, sizeof(header->size));
|
|
|
|
if (out && index == wanted) {
|
|
out->name = header->name;
|
|
out->data = cursor + 512;
|
|
out->size = size;
|
|
out->isDir = header->typeflag == '5';
|
|
return true;
|
|
}
|
|
|
|
uint64 advance = 512 + ((size + 511) & ~(uint64)511);
|
|
cursor += advance;
|
|
index++;
|
|
}
|
|
|
|
if (total)
|
|
*total = index;
|
|
return false;
|
|
}
|
|
|
|
uint32 initrdCount(void)
|
|
{
|
|
uint32 total = 0;
|
|
walk((uint32)-1, nullptr, &total);
|
|
return total;
|
|
}
|
|
|
|
bool initrdAt(uint32 index, UstarEntry* out)
|
|
{
|
|
return walk(index, out, nullptr);
|
|
}
|