81 lines
2.1 KiB
C++
81 lines
2.1 KiB
C++
#include "init/InitRD.h"
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#include "bootboot.h"
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#include "io/Serial.h"
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#include "std/stdlib.h"
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#include <string.h>
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extern BOOTBOOT bootboot;
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static inline int get_file_size_in_blocks(InitRD::File f)
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{
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return f.size_in_blocks;
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}
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inline int InitRD::get_total_blocks()
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{
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return bootboot.initrd_size / TAR_BLOCKSIZE;
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}
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inline InitRD::TarHeader* InitRD::get_block(int block_index)
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{
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return (TarHeader*)(bootboot.initrd_ptr + block_index * TAR_BLOCKSIZE);
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}
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inline bool InitRD::is_valid_header(TarHeader* header)
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{
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return strncmp(header->magic, TAR_MAGIC, 5) == 0;
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}
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InitRD::File InitRD::get_file(TarHeader* header)
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{
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File result;
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result.size = 0;
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memcpy(result.name, header->name, 100);
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result.addr = (void*)(header + TAR_BLOCKSIZE);
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int multiplier =
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1; // why they decided to store the size as an octal-encoded string instead of an integer is beyond me
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for (int i = 10; i >= 0; i--)
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{
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result.size += (multiplier * (header->size[i] - 48));
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multiplier *= 8;
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}
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result.size_in_blocks = result.size / TAR_BLOCKSIZE + 1;
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return result;
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}
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InitRD::File InitRD::find_file(const char* filename)
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{
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int block = 0;
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int total_blocks = get_total_blocks();
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while (block < total_blocks)
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{
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TarHeader* hdr = get_block(block);
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block++;
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if (hdr->typeflag == 53) { continue; } // Directory
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if (!is_valid_header(hdr)) { continue; }
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auto f = get_file(hdr);
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if (strncmp(hdr->name, filename, strlen(filename)) == 0) { return f; }
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block += get_file_size_in_blocks(f);
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}
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File nullFile;
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nullFile.addr = NULL;
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nullFile.size = 0;
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memcpy(nullFile.name, "NULL", 5);
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return nullFile;
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}
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void InitRD::for_each(void (*callback)(File& f))
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{
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int block = 0;
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int total_blocks = get_total_blocks();
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while (block < total_blocks)
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{
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TarHeader* hdr = get_block(block);
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block++;
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if (hdr->typeflag == 53) { continue; } // Directory
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if (!is_valid_header(hdr)) { continue; }
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auto f = get_file(hdr);
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block += get_file_size_in_blocks(f);
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callback(f);
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}
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} |