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); }
int main(int ac, char **av) { int fd, n, i; unsigned long ph, ps, np; long nnote, nnote2, 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 = 12 + ROUNDUP(strlen(arch) + 1) + sizeof(descr); nnote2 = 12 + ROUNDUP(strlen(rpaname) + 1) + sizeof(rpanote); n = read(fd, buf, sizeof(buf)); if (n < 0) { perror("read"); exit(1); } if (memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0) goto notelf; e_class = buf[E_IDENT+EI_CLASS]; if (e_class != ELFCLASS32 && e_class != ELFCLASS64) goto notelf; e_data = buf[E_IDENT+EI_DATA]; if (e_data != ELFDATA2MSB && e_data != ELFDATA2LSB) goto notelf; if (n < E_HSIZE) goto notelf; ph = (e_class == ELFCLASS32 ? GET_32(E_PHOFF) : GET_64(E_PHOFF)); ps = GET_16(E_PHENTSIZE); np = GET_16(E_PHNUM); if (ph < E_HSIZE || ps < PH_HSIZE || np < 1) goto notelf; if (ph + (np + 2) * ps + nnote + nnote2 > n) goto nospace; for (i = 0; i < np; ++i) { if (GET_32(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 < 2 * ps + nnote + nnote2; ++i) if (buf[ph + i] != 0) goto nospace; /* fill in the program header entry */ ns = ph + 2 * ps; PUT_32(ph + PH_TYPE, PT_NOTE); if (e_class == ELFCLASS32) PUT_32(ph + PH_OFFSET, ns); else PUT_64(ph + PH_OFFSET, ns); if (e_class == ELFCLASS32) PUT_32(ph + PH_FILESZ, nnote); else PUT_64(ph + PH_FILESZ, nnote); /* fill in the note area we point to */ /* XXX we should probably make this a proper section */ PUT_32(ns, strlen(arch) + 1); PUT_32(ns + 4, N_DESCR * 4); PUT_32(ns + 8, 0x1275); strcpy((char *) &buf[ns + 12], arch); ns += 12 + strlen(arch) + 1; for (i = 0; i < N_DESCR; ++i, ns += 4) PUT_32BE(ns, descr[i]); /* fill in the second program header entry and the RPA note area */ ph += ps; PUT_32(ph + PH_TYPE, PT_NOTE); if (e_class == ELFCLASS32) PUT_32(ph + PH_OFFSET, ns); else PUT_64(ph + PH_OFFSET, ns); if (e_class == ELFCLASS32) PUT_32(ph + PH_FILESZ, nnote); else PUT_64(ph + PH_FILESZ, nnote2); /* fill in the note area we point to */ PUT_32(ns, strlen(rpaname) + 1); PUT_32(ns + 4, sizeof(rpanote)); PUT_32(ns + 8, 0x12759999); strcpy((char *) &buf[ns + 12], rpaname); ns += 12 + ROUNDUP(strlen(rpaname) + 1); for (i = 0; i < N_RPA_DESCR; ++i, ns += 4) PUT_32BE(ns, rpanote[i]); /* Update the number of program headers */ PUT_16(E_PHNUM, np + 2); /* 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[1]); exit(1); nospace: fprintf(stderr, "sorry, I can't find space in %s to put the note\n", av[1]); exit(1); }