109 lines
3.0 KiB
C
109 lines
3.0 KiB
C
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#include "reloc.h"
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#include "../../runtime/panic_assert.h"
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#include <string.h>
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static inline int __local_strncmp(const char *s1, const char *s2, size_t n) {
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while (n && *s1 && (*s1 == *s2)) {
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++s1;
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++s2;
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--n;
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}
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if (n == 0) {
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return 0;
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} else {
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return (*(unsigned char *)s1 - *(unsigned char *)s2);
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}
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}
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static const char *caseFlags(uint16_t type) {
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#define CASE(expr) \
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case EXECFORMAT_PE_BASERELOC_##expr: \
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return #expr;
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switch (type) {
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CASE(ABSOLUTE)
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CASE(HIGH)
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CASE(LOW)
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CASE(HIGHLOW)
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CASE(HIGHADJ)
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CASE(DIR64)
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default:
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return "(Unknown)";
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}
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#undef CASE
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}
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void execformat_pe_BaseRelocate(execformat_pe_PortableExecutable *pe, void *relocBase, void *relocEnd, uint64_t currentBase, uint64_t targetBase) {
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if (pe->begin == 0)
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return;
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if (currentBase == 0) {
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if (pe->isPE32P)
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currentBase = ((execformat_pe_OptionalHeader_PE32P *)pe->optional)->win.imageBase;
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else
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currentBase = ((execformat_pe_OptionalHeader_PE32 *)pe->optional)->win.imageBase;
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}
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void *reloc = 0, *reloc_end;
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if (relocBase != 0 && relocEnd != 0) {
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reloc = relocBase;
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reloc_end = relocEnd;
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} else {
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// find the .reloc section
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for (int i = 0; i < pe->numSections; i++)
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if (__local_strncmp(pe->sections[i].name, ".reloc", 6) == 0) {
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reloc = pe->begin + pe->sections[i].virtualAddr;
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reloc_end = reloc + pe->sections[i].virtualSize;
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break;
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}
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if (reloc == 0)
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return; // no .reloc section
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}
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uint64_t diff = targetBase - currentBase;
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while (reloc < reloc_end) {
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execformat_pe_BaseRelocBlock *block = reloc;
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int entries = (block->blockSize - 8) / 2;
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assert((block->blockSize - 8) % 2 == 0);
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printf("BaseReloc Block RVA=0x%08x, entries=%d\n", block->pageOffset, entries);
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for (int i = 0; i < entries; i++) {
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void *target = pe->begin + block->pageOffset + (block->entries[i] & EXECFORMAT_PE_BASERELOC_OFFSET_MASK);
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//uint64_t cur = 0, new = 0;
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switch (block->entries[i] & EXECFORMAT_PE_BASERELOC_FLAG_MASK) {
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case EXECFORMAT_PE_BASERELOC_HIGH:
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//cur = *((uint16_t *)target);
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*((uint16_t *)target) += (uint16_t)(diff >> 16);
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//new = *((uint16_t *)target);
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break;
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case EXECFORMAT_PE_BASERELOC_LOW:
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//cur = *((uint16_t *)target);
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*((uint16_t *)target) += (uint16_t)(diff);
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//new = *((uint16_t *)target);
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break;
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case EXECFORMAT_PE_BASERELOC_HIGHLOW:
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//cur = *((uint32_t *)target);
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*((uint32_t *)target) += (uint32_t)(diff);
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//new = *((uint32_t *)target);
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break;
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case EXECFORMAT_PE_BASERELOC_DIR64:
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//cur = *((uint64_t *)target);
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*((uint64_t *)target) += (diff);
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//new = *((uint64_t *)target);
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break;
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case EXECFORMAT_PE_BASERELOC_HIGHADJ:
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i++;
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break;
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}
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//printf(" Reloc Off0x%08llx CUR=0x%08llx(Off0x%08llx), NEW=0x%llx, Type=%s\n", target - pe->begin, cur, cur - currentBase, new, caseFlags(block->entries[i] & EXECFORMAT_PE_BASERELOC_FLAG_MASK));
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}
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reloc += block->blockSize;
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}
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}
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