bfd_boolean
plugin_should_reload (bfd *abfd)
{
return ((abfd->flags & DYNAMIC) != 0
&& bfd_get_flavour (abfd) == bfd_target_elf_flavour
&& bfd_get_format (abfd) == bfd_object
&& (elf_dyn_lib_class (abfd) & DYN_AS_NEEDED) != 0);
}
main (int argc, char **argv) {
bfd *ibfd, *obfd;
asection *p;
static asymbol **osympp, **delsympp;
long symsize, symcount, delsymcount;
int i;
int c;
int idx;
struct add_reloc_struct *new_reloc;
struct change_reloc_struct *new_change;
struct delete_reloc_struct *new_delete;
struct modify_byte_struct *new_modify;
struct globalize_sym_struct *new_globalize;
while ((c = getopt (argc, argv, "a:d:c:m:G:")) != -1) {
switch (c) {
case 'a':
/* check to see if we have two args: name and loc */
if ((index(optarg, ',') == NULL) ||
(index(optarg, ',') != rindex(optarg, ','))) {
fprintf(stderr, "usage: -a argument should be <symbolname>,<location>, not \"%s\"\n", optarg);
exit(1);
}
/* record the add reloc command in the global array */
new_reloc = (add_reloc_struct *)malloc(sizeof(add_reloc_struct));
new_reloc->symbol_name = strndup(optarg, (index(optarg, ',') - optarg));
new_reloc->loc = strtol(index(optarg, ',') + 1, NULL, 0);
if (errno == EINVAL) {
fprintf(stderr, "the value %s is not a valid location for the add command\n", index(optarg, ',') + 1);
exit(1);
}
new_reloc->next = additional_relocs;
additional_relocs = new_reloc;
break;
case 'c':
/* check to see if we have two args */
if ((index(optarg, ',') == NULL) ||
(index(optarg, ',') != rindex(optarg, ','))) {
fprintf(stderr, "usage: -c argument should be <symbolname>,<symbolname>, not \"%s\"\n", optarg);
exit(1);
}
new_change = (change_reloc_struct *)malloc(sizeof(change_reloc_struct));
new_change->old_symbol_name = strndup(optarg, strlen(optarg) - strlen(index(optarg, ',')));
new_change->new_symbol_name = strdup(index(optarg, ',') + 1);
new_change->next = change_relocs;
change_relocs = new_change;
break;
case 'd':
new_delete = (delete_reloc_struct *)malloc(sizeof(delete_reloc_struct));
new_delete->symbol_name = strdup(optarg);
new_delete->next = delete_relocs;
delete_relocs = new_delete;
break;
case 'm':
if ((index(optarg, '=') == NULL) ||
(index(optarg, '=') != rindex(optarg, '='))) {
fprintf(stderr, "usage: -m argument should be <location>=<value>, not \"%s\"\n", optarg);
exit(1);
}
new_modify = (modify_byte_struct *)malloc(sizeof(modify_byte_struct));
new_modify->location = strtol(optarg, NULL, 0);
new_modify->value = strtol(index(optarg, '=') + 1, NULL, 0);
if (new_modify->value > 0xff) {
fprintf(stderr, "requested modify value %lx for location %lx exceeds 0xff\n",
new_modify->value, new_modify->location);
exit(1);
}
new_modify->next = modify_bytes;
modify_bytes = new_modify;
break;
case 'G':
new_globalize = (globalize_sym_struct *)malloc(sizeof(globalize_sym_struct));
new_globalize->symbol_name = strdup(optarg);
new_globalize->next = globalize_syms;
globalize_syms = new_globalize;
break;
default:
fprintf(stderr, "unrecognized argument character |%c|\n", c);
}
}
if ((argc - optind) != 2) {
fprintf(stderr, "usage: fixup_relocs [-a newsymbol,location] [-c oldsymbol,newsymbol] [-d symbol] infile.o outfile.o\n");
exit(1);
}
ibfd = bfd_openr(argv[optind], NULL);
if (ibfd == NULL) {
bfd_perror("while opening input object file");
exit(1);
}
/* if I don't do "check_format", there's no data in the bfd object. wtf? */
if (!bfd_check_format(ibfd, bfd_object)) {
fprintf(stderr, "input file %s seems to NOT be an object file! exiting.\n", argv[optind]);
exit(1);
}
obfd = bfd_openw(argv[optind+1], bfd_get_target(ibfd));
if (obfd == NULL) {
bfd_perror("while opening output object file");
exit(1);
}
if (!bfd_set_format(obfd, bfd_get_format(ibfd))) {
bfd_perror("while setting output object file format");
}
/* copy a bunch of necessary global stuff */
bfd_set_start_address(obfd, bfd_get_start_address(ibfd));
bfd_set_file_flags(obfd, bfd_get_file_flags(ibfd));
bfd_set_arch_mach(obfd, bfd_get_arch(ibfd), bfd_get_mach(ibfd));
/* BOZO objcopy sets format again at this point. why? */
bfd_map_over_sections (ibfd, setup_section, obfd);
setup_bfd_headers (ibfd, obfd);
/* Symbol filtering must happen after the output sections
have been created, but before their contents are set. */
symsize = bfd_get_symtab_upper_bound (ibfd);
if (symsize < 0) {
fprintf(stderr, "problem processing %s\n", bfd_get_filename (ibfd));
return FALSE;
}
/* count the added relocations so we can put extra space in the output symbol table for them */
int reloc_add_cnt, reloc_delete_cnt;
reloc_add_cnt = 0;
reloc_delete_cnt = 0;
for (new_reloc = additional_relocs; new_reloc != NULL; new_reloc = new_reloc->next) {
reloc_add_cnt++;
}
/* the "change" symbols might also not be in the symbol table yet */
for (new_change = change_relocs; new_change != NULL; new_change = new_change->next) {
reloc_add_cnt++;
/* the old symbol may be deleted, also */
reloc_delete_cnt++;
}
for (new_delete = delete_relocs; new_delete != NULL; new_delete = new_delete->next) {
reloc_delete_cnt++;
}
/* filter symbol table in two steps: */
/* 1) move symbols bound for deletion to the end of the output symbol table array */
/* 2) truncate the table at the first of those */
/* this makes it possible to do the reloc processing with the symbol table intact, */
/* and remove the deleted symbols afterwards, without corrupting the reloc data structures */
isympp = malloc (symsize);
osympp = malloc (symsize + reloc_add_cnt * sizeof(asymbol *));
delsympp = malloc (reloc_delete_cnt * sizeof(asymbol *));
symcount = bfd_canonicalize_symtab (ibfd, isympp);
if (symcount < 0) {
fprintf(stderr, "problem processing %s\n", bfd_get_filename (ibfd));
return FALSE;
}
/* remove any undefined symbols whose relocation entries were deleted or changed */
int osym_idx, delsym_idx;
osym_idx = delsym_idx = 0;
delsymcount = 0;
for (i = 0; i < symcount; i++) {
if ((is_delete_reloc(bfd_asymbol_name(isympp[i]), delete_relocs) ||
(find_change_reloc(bfd_asymbol_name(isympp[i]), change_relocs) != NULL)) &&
(isympp[i]->section != NULL) &&
(strcmp(isympp[i]->section->name, BFD_UND_SECTION_NAME) == 0)) {
delsympp[delsym_idx++] = isympp[i];
}
else {
if (is_globalize_sym(bfd_asymbol_name(isympp[i]), globalize_syms)) {
isympp[i]->flags = BSF_GLOBAL;
}
osympp[osym_idx++] = isympp[i];
}
}
symcount = osym_idx;
delsymcount = delsym_idx;
osympp[symcount] = NULL;
/* add the symbols for additional relocs to the table */
int added_symbol_cnt = 0;
for (new_reloc = additional_relocs; new_reloc != NULL; new_reloc = new_reloc->next) {
if (find_symbol(osympp, new_reloc->symbol_name) < 0) {
/* not yet present, so add it */
asymbol *new_sym;
new_sym = bfd_make_empty_symbol(obfd);
new_sym->name = strdup(new_reloc->symbol_name);
new_sym->section = bfd_get_section_by_name (obfd, ".text");
new_sym->value = new_reloc->loc;
new_sym->flags = BSF_GLOBAL;
osympp[symcount + added_symbol_cnt++] = new_sym;
osympp[symcount + added_symbol_cnt] = NULL;
}
}
/* do the same for changed relocs */
for (new_change = change_relocs; new_change != NULL; new_change = new_change->next) {
if (find_symbol(osympp, new_change->new_symbol_name) < 0) {
/* not yet present, so add it */
/* since this is a name change, we will reuse the existing address (value field of reloc) */
int old_symbol_idx;
if ((old_symbol_idx = find_symbol(isympp, new_change->old_symbol_name)) < 0) {
fprintf(stderr, "change command old symbol name %s not found in symbol table! Exiting.\n", new_change->old_symbol_name);
exit(1);
}
asymbol *new_sym;
new_sym = bfd_make_empty_symbol(obfd);
new_sym->name = strdup(new_change->new_symbol_name);
new_sym->section = bfd_und_section_ptr;
new_sym->value = isympp[old_symbol_idx]->value;
new_sym->flags = BSF_GLOBAL;
fprintf(stderr, "adding new symbol %s for change reloc command\n", new_sym->name);
osympp[symcount + added_symbol_cnt++] = new_sym;
osympp[symcount + added_symbol_cnt] = NULL;
}
}
/* append the soon-to-be deleted symbols to the end of the output symbol table */
for (i = 0; i < delsymcount; i++) {
osympp[symcount + added_symbol_cnt + i] = delsympp[i];
}
osympp[symcount + added_symbol_cnt + delsymcount] = NULL;
bfd_set_symtab (obfd, osympp, symcount + added_symbol_cnt + delsymcount);
/* This has to happen after the symbol table has been set. */
bfd_map_over_sections (ibfd, copy_section_relocs_edit, obfd);
/* now truncate the symbol table to eliminate the deleted symbols */
osympp[symcount + added_symbol_cnt] = NULL;
bfd_set_symtab (obfd, osympp, symcount + added_symbol_cnt);
/* now that we've set the relocs and cleaned the symtab, can call this */
bfd_map_over_sections (ibfd, copy_section_data, obfd);
bfd_close(obfd);
bfd_close(ibfd);
return 0;
}
void replace_hello(const char *input_path, const char *output_path)
{
bfd_init();
bfd *ibfd = bfd_openr(input_path, NULL);
if (ibfd == NULL)
errx(1, bfd_errmsg(bfd_get_error()));
if (!bfd_check_format(ibfd, bfd_object)) {
bfd_close_all_done(ibfd);
errx(1, "Input file is not a valid object file.");
}
bfd *obfd = bfd_openw(output_path, bfd_get_target(ibfd));
if (obfd == NULL) {
bfd_close_all_done(ibfd);
errx(1, bfd_errmsg(bfd_get_error()));
}
if (!bfd_set_format(obfd, bfd_get_format(ibfd))) {
bfd_close_all_done(ibfd);
bfd_close_all_done(obfd);
errx(1, "Setting obfd format failed: %s\n", bfd_errmsg(bfd_get_error()));
}
bfd_set_arch_info(obfd, bfd_get_arch_info(ibfd));
// Create sections for .data
asection *section = bfd_get_section_by_name(ibfd, ".data");
while (section != NULL) {
if (section->flags & SEC_HAS_CONTENTS) {
char *section_contents = (char *)malloc(section->size);
bfd_get_section_contents(ibfd, section, section_contents, 0, section->size);
char *hello_pos = (char *)memmem(section_contents, section->size, "hello", 5);
if (hello_pos != NULL) {
if (bfd_make_section_anyway_with_flags(obfd, ".data", section->flags) == NULL) {
free(section_contents);
bfd_close_all_done(ibfd);
bfd_close_all_done(obfd);
errx(1, bfd_errmsg(bfd_get_error()));
}
}
free(section_contents);
}
section = bfd_get_next_section_by_name(ibfd, section);
}
asection *comment_section = bfd_make_section_anyway_with_flags(obfd, ".comment.my_objcopy", SEC_HAS_CONTENTS);
if (comment_section == NULL) {
bfd_close_all_done(ibfd);
bfd_close_all_done(obfd);
errx(1, bfd_errmsg(bfd_get_error()));
}
if (!bfd_set_section_size(obfd, comment_section, 3)) {
bfd_close_all_done(ibfd);
bfd_close_all_done(obfd);
errx(1, bfd_errmsg(bfd_get_error()));
}
if (!bfd_set_section_contents(obfd, comment_section, "moo", 0, 3)) {
bfd_close_all_done(ibfd);
bfd_close_all_done(obfd);
errx(1, bfd_errmsg(bfd_get_error()));
}
// section = bfd_get_section_by_name(ibfd, ".data");
// asection *osection = bfd_get_section_by_name(obfd, ".data");
// if (osection == NULL) {
// bfd_close_all_done(ibfd);
// bfd_close_all_done(obfd);
// errx(1, bfd_errmsg(bfd_get_error()));
// }
// while (section != NULL) {
// if (section->flags & SEC_HAS_CONTENTS) {
// char *section_contents = (char *)malloc(section->size);
// bfd_get_section_contents(ibfd, section, section_contents, 0, section->size);
//
// char *hello_pos = (char *)memmem(section_contents, section->size, "hello", 5);
// if (hello_pos != NULL) {
// hello_pos[1] = 'o';
// hello_pos[4] = 'a';
// if (bfd_set_section_contents(obfd, osection, section_contents, 0, section->size)) {
// free(section_contents);
// bfd_close_all_done(ibfd);
// bfd_close_all_done(obfd);
// errx(1, bfd_errmsg(bfd_get_error()));
// }
// }
//
// free(section_contents);
// osection = bfd_get_next_section_by_name(obfd, osection);
// }
//
// section = bfd_get_next_section_by_name(ibfd, section);
// }
if (!bfd_close(obfd))
errx(1, "Closing obfd failed: %s\n", bfd_errmsg(bfd_get_error()));
if (!bfd_close(ibfd))
errx(1, "Closing ibfd failed: %s\n", bfd_errmsg(bfd_get_error()));
}
int main(int argc, char * argv[])
{
bfd * bfd_in;
bfd * bfd_out;
char * filename_in;
char * filename_out;
log_init(PROGRAM_NAME, LOG_MESSAGE);
atexit(log_fini);
filename_in = NULL;
filename_out = NULL;
int c;
// int digit_optind = 0;
while (1) {
// int this_option_optind = optind ? optind : 1;
int option_index = 0;
static struct option long_options[] = {
{ "input", 1, 0, 'i' },
{ "output", 1, 0, 'o' },
{ "debug", 0, 0, 'd' },
{ "verbose", 0, 0, 'v' },
{ "version", 0, 0, 'V' },
{ "help", 0, 0, 'h' },
{ 0, 0, 0, 0 }
};
c = getopt_long(argc, argv, "i:o:dvVh",
long_options, &option_index);
if (c == -1) {
break;
}
debug("Handling option character '%c'\n", c);
switch (c) {
case 'i':
filename_in = optarg;
break;
case 'o':
filename_out = optarg;
break;
case 'd':
log_level(LOG_DEBUG);
break;
case 'v':
log_level(LOG_VERBOSE);
break;
case 'V':
version(PROGRAM_NAME);
return 0;
case 'h':
help();
return 0;
case '?':
hint(PROGRAM_NAME, "Unrecognized option");
return 1;
default:
BUG();
return 1;
}
}
if (!filename_in) {
fatal("Missing input filename\n");
exit(EXIT_FAILURE);
}
if (!filename_out) {
fatal("Missing output filename\n");
exit(EXIT_FAILURE);
}
/* XXX FIXME: Use stat instead of strcmp */
if (!strcmp(filename_in, filename_out)) {
fatal("Input and output are the same file\n");
exit(EXIT_FAILURE);
}
bfd_init();
debug("Reading input file %s\n", filename_in);
bfd_in = bfd_openr(filename_in, NULL);
if (!bfd_in) {
fatal("Cannot open input file %s (%s)\n",
filename_in, BFD_strerror());
exit(EXIT_FAILURE);
}
if (!bfd_check_format(bfd_in, bfd_object)) {
fatal("Wrong input file format (not an object)\n");
exit(EXIT_FAILURE);
}
bfd_out = bfd_openw(filename_out, NULL);
if (!bfd_out) {
fatal("Cannot open output file %s (%s)\n",
filename_out, BFD_strerror());
exit(EXIT_FAILURE);
}
debug("Generating output file %s\n", filename_out);
bfd_set_format(bfd_out, bfd_get_format(bfd_in));
if (bfd_copy_private_bfd_data(bfd_in, bfd_out) == FALSE) {
fatal("Cannot copy private bfd data (%s)\n",
BFD_strerror());
exit(EXIT_FAILURE);
}
if (bfd_copy_private_header_data(bfd_in, bfd_out) == FALSE) {
fatal("Cannot copy private header data (%s)\n",
BFD_strerror());
exit(EXIT_FAILURE);
}
bfd_close(bfd_in);
bfd_close(bfd_out);
exit(EXIT_SUCCESS);
}
