/* * BK Id: SCCS/s.addnote.c 1.7 05/18/01 15:17:23 cort *//* * Program to hack in a PT_NOTE program header entry in an ELF file. * This is needed for OF on RS/6000s to load an image correctly. * Note that OF needs a program header entry for the note, not an * ELF section. * * Copyright 2000 Paul Mackerras. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Usage: addnote zImage */#include <stdio.h>#include <fcntl.h>#include <unistd.h>#include <string.h>char arch[] = "PowerPC";#define N_DESCR	6unsigned int descr[N_DESCR] = {#if 1	/* values for IBM RS/6000 machines */	0xffffffff,		/* real-mode = true */	0x00c00000,		/* real-base, i.e. where we expect OF to be */	0xffffffff,		/* real-size */	0xffffffff,		/* virt-base */	0xffffffff,		/* virt-size */	0x4000,			/* load-base */#else	/* values for longtrail CHRP */	0,			/* real-mode = false */	0xffffffff,		/* real-base */	0xffffffff,		/* real-size */	0xffffffff,		/* virt-base */	0xffffffff,		/* virt-size */	0x00600000,		/* load-base */#endif};unsigned char buf[512];#define GET_16BE(off)	((buf[off] << 8) + (buf[(off)+1]))#define GET_32BE(off)	((GET_16BE(off) << 16) + GET_16BE((off)+2))#define PUT_16BE(off, v)	(buf[off] = ((v) >> 8) & 0xff, \				 buf[(off) + 1] = (v) & 0xff)#define PUT_32BE(off, v)	(PUT_16BE((off), (v) >> 16), \				 PUT_16BE((off) + 2, (v)))/* Structure of an ELF file */#define E_IDENT		0	/* ELF header */#define	E_PHOFF		28#define E_PHENTSIZE	42#define E_PHNUM		44#define E_HSIZE		52	/* size of ELF header */#define EI_MAGIC	0	/* offsets in E_IDENT area */#define EI_CLASS	4#define EI_DATA		5#define PH_TYPE		0	/* ELF program header */#define PH_OFFSET	4#define PH_FILESZ	16#define PH_HSIZE	32	/* size of program header */#define PT_NOTE		4	/* Program header type = note */#define ELFCLASS32	1#define ELFDATA2MSB	2unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' };int main(int ac, char **av){	int fd, n, i;	int ph, ps, np;	int nnote, ns;	if (ac != 2) {		fprintf(stderr, "Usage: %s elf-file\n", av[0]);		exit(1);	}	fd = open(av[1], O_RDWR);	if (fd < 0) {		perror(av[1]);		exit(1);	}	nnote = strlen(arch) + 1 + (N_DESCR + 3) * 4;	n = read(fd, buf, sizeof(buf));	if (n < 0) {		perror("read");		exit(1);	}	if (n < E_HSIZE || memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0)		goto notelf;	if (buf[E_IDENT+EI_CLASS] != ELFCLASS32	    || buf[E_IDENT+EI_DATA] != ELFDATA2MSB) {		fprintf(stderr, "%s is not a big-endian 32-bit ELF image\n",			av[1]);		exit(1);	}	ph = GET_32BE(E_PHOFF);	ps = GET_16BE(E_PHENTSIZE);	np = GET_16BE(E_PHNUM);	if (ph < E_HSIZE || ps < PH_HSIZE || np < 1)		goto notelf;	if (ph + (np + 1) * ps + nnote > n)		goto nospace;	for (i = 0; i < np; ++i) {		if (GET_32BE(ph + PH_TYPE) == PT_NOTE) {			fprintf(stderr, "%s already has a note entry\n",				av[1]);			exit(0);		}		ph += ps;	}	/* XXX check that the area we want to use is all zeroes */	for (i = 0; i < ps + nnote; ++i)		if (buf[ph + i] != 0)			goto nospace;	/* fill in the program header entry */	ns = ph + ps;	PUT_32BE(ph + PH_TYPE, PT_NOTE);	PUT_32BE(ph + PH_OFFSET, ns);	PUT_32BE(ph + PH_FILESZ, nnote);	/* fill in the note area we point to */	/* XXX we should probably make this a proper section */	PUT_32BE(ns, strlen(arch) + 1);	PUT_32BE(ns + 4, N_DESCR * 4);	PUT_32BE(ns + 8, 0x1275);	strcpy(&buf[ns + 12], arch);	ns += 12 + strlen(arch) + 1;	for (i = 0; i < N_DESCR; ++i)		PUT_32BE(ns + i * 4, descr[i]);	/* Update the number of program headers */	PUT_16BE(E_PHNUM, np + 1);	/* write back */	lseek(fd, (long) 0, SEEK_SET);	i = write(fd, buf, n);	if (i < 0) {		perror("write");		exit(1);	}	if (i < n) {		fprintf(stderr, "%s: write truncated\n", av[1]);		exit(1);	}	exit(0); notelf:	fprintf(stderr, "%s does not appear to be an ELF file\n", av[0]);	exit(1); nospace:	fprintf(stderr, "sorry, I can't find space in %s to put the note\n",		av[0]);	exit(1);}