Files
SplitBit-Emulator/Source/Assembler/firstPass.c
T
Anachronaut b50210d127 Fixed use-after-free in Assembler
Use after free occurred in main() in the case that a program being assembled was longer than the initially allocated intermediate array.
2026-04-27 16:58:43 -04:00

131 lines
5.5 KiB
C

// firstPass.c
// Functions for the 'first pass' of the SplitBit Assembler.
// The first pass' primary goal is to get all the assembly files loaded into the Intermediate Array.
// Because I want included files to load and assemble in-line with the current file, that needs to be handled at this stage.
// Written by Anachronaut
// 10/25/2024
#include <stdlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include "firstPass.h"
#include "Assm-util.h"
#include "assembly.h"
char *includeList[MAX_INCLUDES];
int includeCount = 0;
void freeIncludeList() {
for (int i = 0; i < includeCount; i++) {
if (includeList[i]) {
free(includeList[i]);
}
}
includeCount = 0;
}
int isFileIncluded(const char *fileName) {
for (int i = 0; i < includeCount; i++) {
if (strcmp(includeList[i], fileName) == 0) {
return 1;
}
}
return 0;
}
void addIncludedFile(const char *fileName) {
if (includeCount < MAX_INCLUDES) {
includeList[includeCount] = strdup(fileName);
includeCount++;
} else {
fprintf(stderr, RED "Error: Too many included files.\n" RESET);
exit(1);
}
}
int loadFile(intermediateElement **intermediateArray, char *fileName, int *intermediateIndex, size_t *arraySize){
// Initial setup.
addIncludedFile(fileName);
int status = NOWHERE;
int lineNumber = 1; // Line numbers start at 1.
// Open the file.
FILE *file = fopen(fileName, "r");
if (!file) {
fprintf(stderr, RED "Error: Couldn't open file \"%s\"\n" RESET, fileName);
exit(1);
}
// Read off tokens.
while (readToken(&(*intermediateArray)[*intermediateIndex], file, &lineNumber)) {
if (*intermediateIndex >= *arraySize - 1) {
*arraySize *= 2; // Double the size of the array
*intermediateArray = realloc(*intermediateArray, *arraySize * sizeof(intermediateElement));
if (!intermediateArray) {
fprintf(stderr, RED "Error: Memory reallocation failed.\n" RESET);
exit(1);
}
}
//printf("Token number %d\n", intermediateIndex);
// Go ahead and mark what we already know about this token.
(*intermediateArray)[*intermediateIndex].fileName = fileName;
(*intermediateArray)[*intermediateIndex].lineNumber = lineNumber;
// Take a look at it and determine what it is.
int testValue = checkIfKeyword(&(*intermediateArray)[*intermediateIndex]);
if(testValue > 0) {
switch (testValue){
case KEYWORD_INCLUDE:
// We need to load another file and process it before continuing.
status = NOWHERE;
// Get the filename and load up the file.
(*intermediateIndex)++;
readToken(&(*intermediateArray)[*intermediateIndex], file, &lineNumber);
char *includeFile = (*intermediateArray)[*intermediateIndex].token;
if (isFileIncluded(includeFile)) {
fprintf(stderr, RED "Error: File %s is included more than once.\n" RESET, includeFile);
printf(" File: %s at line %d.\n", fileName, lineNumber);
exit(1);
}
loadFile(intermediateArray, includeFile, intermediateIndex, arraySize);
break;
case KEYWORD_PROGRAM:
// Set the state PROGRAM so we mark additional tokens for inclusion into Program Memory.
status = PROGRAM;
break;
case KEYWORD_DATA:
// Set the state to DATA so we mark additional tokens for inclusion into Data Memory.
status = DATA;
break;
}
// Next, check to see if it's an instruction.
} else if (checkIfInstruction(&(*intermediateArray)[*intermediateIndex])) {
// We should check if we're set up to mark this for the Program Segment.
if (status != PROGRAM) {
fprintf(stderr, RED "Error: Attempting to assemble outside the Program Segment.\n Did you forget to use the #Program keyword?\n" RESET);
printf(" File: %s at line %d.\n", fileName, lineNumber);
exit(1);
}
// Next, check if it's a literal value.
} else if (checkIfLiteralValue(&(*intermediateArray)[*intermediateIndex])) {
// We should check to make sure we have a destination for it.
if (status == NOWHERE) {
fprintf(stderr, RED "Error: Attempting to write a value to nowhere!\n Did you forget to use the #Program or #Data keyword?\n" RESET);
printf(" File: %s at line %d.\n", fileName, lineNumber);
exit(1);
}
// Finally, check if it's a label or label definition.
// First, make sure it hasn't already been marked as a string literal.
} else if ((*intermediateArray)[*intermediateIndex].type != STRING) {
if (checkIfLabel(&(*intermediateArray)[*intermediateIndex])) {
if (status == NOWHERE) {
fprintf(stderr, RED "Error: Attempting to create or use a label nowhere!\n Did you forget to use the #Program or #Data keyword?\n" RESET);
printf(" File: %s at line %d.\n", fileName, lineNumber);
exit(1);
}
}
}
(*intermediateArray)[*intermediateIndex].destination = status;
(*intermediateIndex)++;
}
return 0;
}