| /* |
| * 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 6 |
| unsigned 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 2 |
| |
| unsigned 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); |
| } |