97 lines
2.5 KiB
C
97 lines
2.5 KiB
C
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/*
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* CS 261 PA2: Mini-ELF loader
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*
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* Name: Nicholas Tamassia
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* This code was developed in compliance with the JMU Honor Code.
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*/
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#include "p2-load.h"
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/**********************************************************************
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* REQUIRED FUNCTIONS
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*********************************************************************/
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bool read_phdr (FILE *file, uint16_t offset, elf_phdr_t *phdr)
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{
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if (!file || !phdr || fseek(file, offset, SEEK_SET) != 0) {
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return false;
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}
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return ((fread(phdr, sizeof(elf_phdr_t), 1, file) == 1) && phdr->magic == 0xDEADBEEF);
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}
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bool load_segment (FILE *file, byte_t *memory, elf_phdr_t *phdr)
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{
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if (!file || !memory || !phdr) {
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return false;
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}
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if (phdr->p_vaddr + phdr->p_size > MEMSIZE || fseek(file, phdr->p_offset, SEEK_SET) != 0) {
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return false;
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}
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if ((fread(memory + phdr->p_vaddr, phdr->p_size, 1, file) != 1) && phdr->p_size != 0) {
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return false;
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}
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return true;
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}
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/**********************************************************************
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* OPTIONAL FUNCTIONS
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*********************************************************************/
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void dump_phdrs (uint16_t numphdrs, elf_phdr_t *phdrs)
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{
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printf(" Segment Offset Size VirtAddr Type Flags\n");
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for (int i = 0; i < numphdrs; i++) {
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elf_phdr_t phdr = phdrs[i];
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char flags[4] = "RWX";
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for (int j = 2; j >= 0; j--) {
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if ((phdr.p_flags & (1 << (2 - j))) == 0) {
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flags[j] = ' ';
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}
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}
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printf(" %02d 0x%04x 0x%04x 0x%04x %-10s%s\n", i, phdr.p_offset, phdr.p_size, phdr.p_vaddr, p_type_mapper(phdr.p_type), flags);
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}
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}
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char* p_type_mapper(uint16_t type) {
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switch (type) {
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case 0: return "DATA"; break;
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case 1: return "CODE"; break;
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case 2: return "STACK"; break;
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case 3: return "HEAP"; break;
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default: return "UNKNOWN"; break;
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}
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}
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void dump_memory (byte_t *memory, uint16_t start, uint16_t end)
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{
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printf("Contents of memory from %04x to %04x:\n", start, end);
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int aligned_start = start - (start % 16);
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for (int i = aligned_start; i < end; i++) {
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if (i % 16 == 0) {
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printf(" %04x ", i);
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}
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if (i >= start) {
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printf(" %02x", memory[i]);
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} else {
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printf(" ");
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}
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if (i % 16 == 15 || i == end - 1) {
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printf("\n");
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} else if (i % 16 == 7) {
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printf(" ");
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}
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}
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}
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