/* This is a modified DXEGEN.C. Here are the original DXEGEN.C's
   copyright notices:

   Copyright (C) 1995 Charles Sandmann (sandmann@clio.rice.edu)
   This software may be freely distributed with above copyright, no warranty.
   Based on code by DJ Delorie, it's really his, enhanced, bugs fixed. */

#include "vbeaf.h"
#include <coff.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

extern AF_DRIVER drvhdr;

void exit_cleanup(void) {
	remove("drv__tmp.o");
}

int main(int argc, char **argv) {
	int errors = 0;
	unsigned bss_start = 0;
	FILHDR fh;
	FILE *input_f, *output_f;
	SCNHDR sc;
	char *data, *strings;
	SYMENT *sym;
	RELOC *relocs;
	int strsz, i;
	long init1_offset, init2_offset, init3_offset, element_size, nrelocs,
	    vbe_size;

	if (argc < 6) {
		printf("Usage: drvgen output.drv oemext pnpinit initdrv input.o "
		       "[input2.o ... -lgcc -lc]\n");
		return 1;
	}

	input_f = fopen(argv[5], "rb");
	if (!input_f) {
		perror(argv[5]);
		return 1;
	}

	fread(&fh, 1, FILHSZ, input_f);
	if (fh.f_nscns != 1 || argc > 5) {
		char command[1024];
		fclose(input_f);

		strcpy(command, "ld -X -S -r -o drv__tmp.o -L");
		strcat(command, getenv("DJDIR"));
		strcat(command, "/lib ");
		for (i = 5; argv[i]; i++) {
			strcat(command, argv[i]);
			strcat(command, " ");
		}
		strcat(command, "-T ../drv.ld");

		printf("%s\n", command);
		i = system(command);
		if (i) return i;

		input_f = fopen("drv__tmp.o", "rb");
		if (!input_f) {
			perror(argv[5]);
			return 1;
		} else
			atexit(exit_cleanup);

		fread(&fh, 1, FILHSZ, input_f);
		if (fh.f_nscns != 1) {
			printf("Error: input file has more than one section; use -M for "
			       "map\n");
			return 1;
		}
	}

	fseek(input_f, fh.f_opthdr, 1);
	fread(&sc, 1, SCNHSZ, input_f);

	init1_offset = -1;
	init2_offset = -1;
	init3_offset = -1;
	element_size = sc.s_size;
	nrelocs = sc.s_nreloc;

	data = malloc(sc.s_size);
	fseek(input_f, sc.s_scnptr, 0);
	fread(data, 1, sc.s_size, input_f);

	sym = malloc(sizeof(SYMENT) * fh.f_nsyms);
	fseek(input_f, fh.f_symptr, 0);
	fread(sym, fh.f_nsyms, SYMESZ, input_f);
	fread(&strsz, 1, 4, input_f);
	strings = malloc(strsz);
	fread(strings + 4, 1, strsz - 4, input_f);
	strings[0] = 0;
	for (i = 0; i < (int)fh.f_nsyms; i++) {
		char tmp[9], *name;
		if (sym[i].e.e.e_zeroes) {
			memcpy(tmp, sym[i].e.e_name, 8);
			tmp[8] = 0;
			name = tmp;
		} else
			name = strings + sym[i].e.e.e_offset;
#if 0
    printf("[%3d] 0x%08x 0x%04x 0x%04x %d %s\n",
	   i,
	   sym[i].e_value,
	   sym[i].e_scnum & 0xffff,
	   sym[i].e_sclass,
	   sym[i].e_numaux,
	   name
	   );
#endif
		if (sym[i].e_scnum == 0) {
			printf("Error: object contains unresolved external symbols (%s)\n",
			       name);
			errors++;
		}
		if (strncmp(name, argv[2], strlen(argv[2])) == 0) {
			if (init1_offset != -1) {
				printf("Error: multiple symbols that start with %s (%s)!\n",
				       argv[2], name);
				errors++;
			}
			init1_offset = sym[i].e_value;
		} else if (strncmp(name, argv[3], strlen(argv[3])) == 0) {
			if (init2_offset != -1) {
				printf("Error: multiple symbols that start with %s (%s)!\n",
				       argv[3], name);
				errors++;
			}
			init2_offset = sym[i].e_value;
		} else if (strncmp(name, argv[4], strlen(argv[4])) == 0) {
			if (init3_offset != -1) {
				printf("Error: multiple symbols that start with %s (%s)!\n",
				       argv[4], name);
				errors++;
			}
			init3_offset = sym[i].e_value;
		} else if (strcmp(name, ".bss") == 0 && !bss_start) {
			bss_start = sym[i].e_value;
			/*      printf("bss_start 0x%x\n",bss_start); */
			memset(data + bss_start, 0, sc.s_size - bss_start);
		}
		i += sym[i].e_numaux;
	}

	if (init1_offset == -1) {
		printf("Error: symbol %s not found!\n", argv[2]);
		errors++;
	}

	if (init2_offset == -1) {
		printf("Error: symbol %s not found!\n", argv[3]);
		errors++;
	}

	if (init3_offset == -1) {
		printf("Error: symbol %s not found!\n", argv[4]);
		errors++;
	}

	relocs = malloc(sizeof(RELOC) * sc.s_nreloc);
	fseek(input_f, sc.s_relptr, 0);
	fread(relocs, sc.s_nreloc, RELSZ, input_f);
#if 0
  for (i=0; i<sc.s_nreloc; i++)
    printf("0x%08x %3d 0x%04x - 0x%08x\n",
	   relocs[i].r_vaddr,
	   relocs[i].r_symndx,
	   relocs[i].r_type,
	   *(long *)(data + relocs[i].r_vaddr)
	   );
#endif

	fclose(input_f);
	if (errors) return errors;

	output_f = fopen(argv[1], "wb");
	if (!output_f) {
		perror(argv[1]);
		return 1;
	}

	for (i = 0; i < sc.s_nreloc; i++)
		if (relocs[i].r_type == 0x14) /* Don't do these, they are relative */
			nrelocs--;

	vbe_size = sizeof(drvhdr) + (1 + nrelocs) * sizeof(long);
	drvhdr.OemExt = (void *)(vbe_size + init1_offset);
	drvhdr.PlugAndPlayInit = (void *)(vbe_size + init2_offset);
	drvhdr.InitDriver = (void *)(vbe_size + init3_offset);

	fwrite(&drvhdr, 1, sizeof(drvhdr), output_f);
	fwrite(&nrelocs, 1, sizeof(nrelocs), output_f);
	for (i = 0; i < sc.s_nreloc; i++)
		if (relocs[i].r_type != 0x14) /* Don't do these, they are relative */
			fwrite(&(relocs[i].r_vaddr), 1, sizeof(long), output_f);
	fwrite(data, 1, sc.s_size, output_f);

	fclose(output_f);
	return 0;
}