/*
* $Source$
* $State$
*
* Simple tool to produce an utterly basic ELF executable
* from an absolute ack.out file. Suitable for operating
* systems like Linux.
*
* This tool produces an executable with a program header
* only and no section header.
*
* Mostly pinched from the ARM cv (and then rewritten in
* ANSI C). Which, according to the comment, was pinched
* from m68k2; therefore I am merely continuing a time-
* honoured tradition.
*
* (I was 10 when the original for this was checked into
* CVS...)
*
* dtrg, 2006-10-17
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdint.h>
#include <string.h>
#include "out.h"
#define ASSERT(x) switch (2) { case 0: case (x): ; }
/* Global settings. */
int bigendian = 0;
int elfabi = 3; /* abi = Linux */
int elfmachine = 3; /* machine = EM_386 */
/* Header and section table of an ack object file. */
struct outhead outhead;
struct outsect outsect[S_MAX];
char* stringarea;
char* outputfile = NULL; /* Name of output file, or NULL */
char* program; /* Name of current program: argv[0] */
FILE* input; /* Input stream */
FILE* output; /* Output stream */
#define readf(a, b, c) fread((a), (b), (int)(c), input)
#define writef(a, b, c) fwrite((a), (b), (int)(c), output)
/* Header and program header table of an ELF object file. */
#define ELF_HEADER_SIZE 0x34
#define PROGRAM_HEADER_SIZE 0x20
#define PROGRAM_HEADER_COUNT 1
unsigned long codeoffset;
const char elf_le_ident_string[] = {
0x7F, 'E', 'L', 'F'
};
/* Output file definitions and such */
#define HDR_LENGTH 32
char hdr[HDR_LENGTH] ;
/* Segment numbers understood by aelflod. */
enum {
TEXT = 0,
ROM,
DATA,
BSS,
NUM_SEGMENTS
};
#define N_EXT 040
#define N_UNDEF 00
#define N_ABS 01
#define N_TEXT 02
#define N_DATA 03
#define N_BSS 04
#define N_FN 037
/* Produce an error message and exit. */
void fatal(const char* s, ...)
{
va_list ap;
fprintf(stderr, "%s: ",program) ;
va_start(ap, s);
vfprintf(stderr, s, ap);
va_end(ap);
fprintf(stderr, "\n");
if (outputfile)
unlink(outputfile);
exit(1);
}
/* Calculate the result of a aligned to b (rounding up if necessary).
* b must be a power of two. */
long align(long a, long b)
{
a += b - 1;
return a & ~(b-1);
}
int follows(struct outsect* pa, struct outsect* pb)
{
/* return 1 if pa follows pb */
return (pa->os_base >= align(pb->os_base+pb->os_size, pa->os_lign));
}
/* Writes a byte. */
void emit8(unsigned char value)
{
writef(&value, 1, 1);
}
/* Writes out 16 and 32 bit words in the appropriate endianness. */
void emit16(unsigned short value)
{
unsigned char buffer[2];
if (bigendian)
{
buffer[0] = (value >> 8) & 0xFF;
buffer[1] = (value >> 0) & 0xFF;
}
else
{
buffer[1] = (value >> 8) & 0xFF;
buffer[0] = (value >> 0) & 0xFF;
}
writef(buffer, 1, sizeof(buffer));
}
void emit32(unsigned long value)
{
unsigned char buffer[4];
if (bigendian)
{
buffer[0] = (value >> 24) & 0xFF;
buffer[1] = (value >> 16) & 0xFF;
buffer[2] = (value >> 8) & 0xFF;
buffer[3] = (value >> 0) & 0xFF;
}
else
{
buffer[3] = (value >> 24) & 0xFF;
buffer[2] = (value >> 16) & 0xFF;
buffer[1] = (value >> 8) & 0xFF;
buffer[0] = (value >> 0) & 0xFF;
}
writef(buffer, 1, sizeof(buffer));
}
/* Copies the contents of a section from the input stream
* to the output stream. */
void emits(struct outsect* section)
{
char buffer[BUFSIZ];
long n = section->os_flen;
while (n > 0)
{
int blocksize = (n > BUFSIZ) ? BUFSIZ : n;
readf(buffer, 1, blocksize);
writef(buffer, 1, blocksize);
n -= blocksize;
}
/* Zero fill any remaining space. */
if (section->os_flen != section->os_size)
{
long n = section->os_size - section->os_flen;
memset(buffer, 0, BUFSIZ);
while (n > 0)
{
int blocksize = (n > BUFSIZ) ? BUFSIZ : n;
writef(buffer, 1, blocksize);
n -= blocksize;
}
}
}
/* Writes out an ELF program header. */
void emitphdr(unsigned long address, unsigned long filesize,
unsigned int memsize, unsigned int alignment, int flags)
{
static unsigned long fileoffset = 0;
emit32(1); /* type = PT_LOAD */
emit32(fileoffset); /* file offset */
emit32(address); /* virtual address */
emit32(0); /* physical address */
emit32(filesize); /* file size */
emit32(memsize); /* memory size */
emit32(flags); /* executable, readable, writable */
emit32(alignment); /* alignment */
fileoffset += filesize;
}
/* Macros from modules/src/object/obj.h */
#define Xchar(ch) ((ch) & 0377)
#define uget2(c) (Xchar((c)[0]) | ((unsigned) Xchar((c)[1]) << 8))
#define get4(c) (uget2(c) | ((long) uget2((c)+2) << 16))
/* Read the ack.out file header. */
int rhead(FILE* f, struct outhead* head)
{
char buf[SZ_HEAD], *c;
if (fread(buf, sizeof(buf), 1, f) != 1)
return 0;
c = buf;
head->oh_magic = uget2(c); c += 2;
head->oh_stamp = uget2(c); c += 2;
head->oh_flags = uget2(c); c += 2;
head->oh_nsect = uget2(c); c += 2;
head->oh_nrelo = uget2(c); c += 2;
head->oh_nname = uget2(c); c += 2;
head->oh_nemit = get4(c); c += 4;
head->oh_nchar = get4(c);
return 1;
}
/* Read an ack.out section header. */
int rsect(FILE* f, struct outsect* sect)
{
char buf[SZ_SECT], *c;
if (fread(buf, sizeof(buf), 1, f) != 1)
return 0;
c = buf;
sect->os_base = get4(c); c += 4;
sect->os_size = get4(c); c += 4;
sect->os_foff = get4(c); c += 4;
sect->os_flen = get4(c); c += 4;
sect->os_lign = get4(c);
return 1 ;
}
int main(int argc, char* argv[])
{
/* General housecleaning and setup. */
input = stdin;
output = stdout;
program = argv[0];
/* Read in and process any flags. */
while ((argc > 1) && (argv[1][0] == '-'))
{
switch (argv[1][1])
{
case 'a':
elfabi = atoi(&argv[1][2]);
break;
case 'b':
bigendian = 1;
break;
case 'h':
fprintf(stderr, "%s: Syntax: aelflod [-a<number>] [-b] [-h] [-l]\n\t[-m<number>] <inputfile> <outputfile>\n",
program);
exit(0);
case 'l':
bigendian = 0;
break;
case 'm':
elfmachine = atoi(&argv[1][2]);
break;
default:
syntaxerror:
fatal("syntax error --- try -h for help");
}
argv++;
argc--;
}
/* Process the rest of the arguments. */
switch (argc)
{
case 1: /* No parameters --- read from stdin, write to stdout. */
break;
case 3: /* Both input and output files specified. */
output = fopen(argv[2], "w");
if (!output)
fatal("unable to open output file.");
outputfile = argv[2];
/* fall through */
case 2: /* Input file specified. */
input = fopen(argv[1], "r");
if (!input)
fatal("unable to open input file.");
break;
default:
goto syntaxerror;
}
/* Read and check the ack.out file header. */
if (!rhead(input,&outhead))
fatal("failed to read file header.");
if (BADMAGIC(outhead))
fatal("this isn't an ack object file.");
if (outhead.oh_nrelo > 0)
fprintf(stderr, "Warning: relocation information present.");
if (!((outhead.oh_nsect == NUM_SEGMENTS) ||
(outhead.oh_nsect == (NUM_SEGMENTS+1))))
fatal("the input file must have %d sections, not %ld.",
NUM_SEGMENTS, outhead.oh_nsect);
/* Read in the section headers. */
{
int i;
for (i=0; i<outhead.oh_nsect; i++)
{
if (!rsect(input, &outsect[i]))
fatal("failed to read section header %d.", i);
}
}
/* A few checks */
if (outsect[BSS].os_flen != 0)
fatal("the bss space contains initialized data.");
if (!follows(&outsect[BSS], &outsect[DATA]))
fatal("the bss segment must follow the data segment.");
if (!follows(& outsect[ROM], &outsect[TEXT]))
fatal("the rom segment must follow the text segment.");
if (!follows(&outsect[DATA], &outsect[ROM]))
fatal("the data segment must follow the rom segment.") ;
/* Check for an optional end segment (which is otherwise
* ignored). */
if (outhead.oh_nsect == (NUM_SEGMENTS+1))
{
if (!follows(&outsect[NUM_SEGMENTS], &outsect[BSS]))
fatal("end segment must follow bss");
if ( outsect[NUM_SEGMENTS].os_size != 0 )
fatal("end segment must be empty");
}
/* Ensure the base address doesn't overlap the file header. */
codeoffset = outsect[TEXT].os_base & 0x1FFF;
if (codeoffset < (ELF_HEADER_SIZE + PROGRAM_HEADER_SIZE*PROGRAM_HEADER_COUNT))
fatal("base address too small --- overlaps ELF header");
/* Rationalise the memory sizes. */
outsect[TEXT].os_size = outsect[ROM ].os_base - outsect[TEXT].os_base;
outsect[ROM ].os_size = outsect[DATA].os_base - outsect[ROM ].os_base;
outsect[DATA].os_size = outsect[BSS ].os_base - outsect[DATA].os_base;
outsect[BSS ].os_size = align(outsect[BSS].os_size, outsect[BSS].os_lign);
/* Write out the ELF file header. */
writef(elf_le_ident_string, 4, 1);
emit8(1); /* class = ELFCLASS32 */
emit8(bigendian ? 2 : 1); /* endianness */
emit8(1); /* ELF version */
emit8(elfabi); /* ABI */
emit8(0); /* ABI version */
emit8(0); emit16(0); /* padding... */
emit32(0); /* ...to offset 0x10 */
emit16(2); /* type = ET_EXEC */
emit16(elfmachine); /* machine */
emit32(1); /* ELF version again */
emit32(outsect[TEXT].os_base); /* entry point */
emit32(ELF_HEADER_SIZE); /* program header offset */
emit32(0); /* section header offset */
emit32(0); /* flags */
emit16(ELF_HEADER_SIZE); /* elf header size */
emit16(PROGRAM_HEADER_SIZE); /* program header entry size */
emit16(1); /* number of program header entries */
emit16(0x28); /* section header entry size */
emit16(0); /* number of section header entries */
emit16(0); /* section header string table index = SHN_UNDEF */
/* Write out a single rwx section for the entire program. */
{
unsigned long filelength = codeoffset +
outsect[TEXT].os_size +
outsect[ROM].os_size +
outsect[DATA].os_size;
unsigned long memlength = filelength +
outsect[BSS].os_size;
emitphdr(outsect[TEXT].os_base & ~0x1FFF, filelength, memlength,
0, 4|2|1);
}
/* Write padding until the code start. */
fseek(output, codeoffset, SEEK_SET);
/* Write out the actual data. */
emits(&outsect[TEXT]);
emits(&outsect[ROM]);
emits(&outsect[DATA]);
if (ferror(output))
fatal("output write error");
if (outputfile)
chmod(outputfile, 0755);
/* Summarise what we've done. */
{
long ss = 0;
printf(" address length\n");
printf(" ehdr : %08lX %08lX\n", outsect[TEXT].os_base & ~0x1FFF, codeoffset);
printf(" text : %08lX %08lX\n", outsect[TEXT].os_base, outsect[TEXT].os_size);
printf(" rom : %08lX %08lX\n", outsect[ROM].os_base, outsect[ROM].os_size);
printf(" data : %08lX %08lX\n", outsect[DATA].os_base, outsect[DATA].os_size);
printf(" bss : %08lX %08lX\n", outsect[BSS].os_base, outsect[BSS].os_size);
ss += outsect[TEXT].os_size;
ss += outsect[ROM].os_size;
ss += outsect[DATA].os_size;
ss += outsect[BSS].os_size;
printf("TOTAL : %08lX\n", ss);
}
return 0;
}