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/*
File rsym_macosx.c
Build an executable rsym for Mac OS X (31 July 2003).
Grab only the external symbols from a Mach-O object file, and put them
in a simple format. This information will be used for relocation.
To compile in standalone mode:
gcc -DDEBUG -I../h -o rsym_macosx rsym_macosx.c
Aurelien Chanudet <aurelien.chanudet(at)m4x.org>
*/
#include <mach-o/loader.h>
#include <mach-o/nlist.h>
#include <mach/mach.h>
#ifndef SPECIAL_RSYM
#define SPECIAL_RSYM
#endif
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#define IN_RSYM 1
/* #include "config.h" */
#include "ext_sym.h"
int verbose = 0;
void rsym_error (char *format, ...)
{
va_list ap;
va_start (ap, format);
fprintf (stderr, "rsym: ");
vfprintf (stderr, format, ap);
/* fprintf (stderr, " (%s)", strerror(errno)); */
fprintf (stderr, "\n");
va_end (ap);
exit (1);
}
int rsym_select_symbol(struct nlist *symbol)
{
if (symbol->n_type & N_STAB) {
return (FALSE);
}
if (!(symbol->n_type & N_EXT)) {
return (FALSE);
}
/* if (symbol->n_type == N_UNDF) {
return (FALSE);
}
if (symbol->n_sect == NO_SECT) {
return (FALSE);
}
*/
return (TRUE);
}
void rsym_doit2 (struct nlist *symbols, unsigned long nsyms, char *outfile)
{
unsigned long i;
struct lsymbol_table tab;
FILE *symout;
if (!(symout = fopen (outfile, "wb"))) {
rsym_error ("cannot open file for writing: %s", outfile);
}
tab.n_symbols=0;
tab.tot_leng=0;
fseek (symout, sizeof(tab), 0);
for (i=0 ; i < nsyms ; i++)
{
int addr = (int) symbols[i].n_value;
char *name = symbols[i].n_un.n_name;
if (name)
{
tab.n_symbols++;
fwrite (&addr, sizeof (int), 1, symout);
while (tab.tot_leng++, *name)
putc (*name++, symout);
putc (0, symout);
}
else {
fprintf (stderr, "warning: malformed symbol\n");
}
}
if (verbose) {
fprintf (stdout, "%d/%ld symbol(s) reviewed\n", tab.n_symbols, nsyms);
}
fseek (symout, 0, 0);
fwrite (&tab, sizeof(tab), 1, symout);
fclose (symout);
}
void rsym_doit1 (char *infile, char *outfile)
{
struct stat stat_buf;
struct mach_header *mh;
struct load_command *lc;
struct symtab_command *st = NULL;
struct dysymtab_command *dyst;
unsigned long nsyms, i, size;
unsigned long strsize;
struct nlist *symtab, *selected_symbols;
kern_return_t r;
char *strtab;
vm_size_t s;
char *addr;
int fd;
if ((fd = open (infile, O_RDONLY, 0)) < 0) {
rsym_error ("cannot open input file: %s", infile);
}
if (fstat (fd, &stat_buf) == -1) {
rsym_error ("cannot fstat file: %s", infile);
}
size = stat_buf.st_size;
if ((r = map_fd (fd, (vm_offset_t) 0, (vm_offset_t *) &addr,
(boolean_t) TRUE, (vm_size_t) size)) != KERN_SUCCESS) {
rsym_error ("cannot map file in memory: %s", infile);
}
mh = (struct mach_header *) addr;
lc = (struct load_command *) ((char *) addr + sizeof(struct mach_header));
for (i=0 ; i < mh->ncmds ; i++) {
if (lc->cmd == LC_SYMTAB) {
st = (struct symtab_command *) lc;
}
else if (lc->cmd == LC_DYSYMTAB) {
dyst = (struct dysymtab_command *) lc;
}
lc = (struct load_command *) ((char *) lc + lc->cmdsize);
}
if (!st) {
rsym_error ("no symbol table information");
}
symtab = (struct nlist *) ((char *) addr + st->symoff);
s = sizeof(struct nlist) * st->nsyms;
if (vm_allocate (mach_task_self (),
(vm_address_t *) &selected_symbols, s, 1) != KERN_SUCCESS) {
rsym_error ("could not vm_allocate");
}
nsyms = 0;
for (i = 0 ; i < st->nsyms ; i++) {
if (rsym_select_symbol (symtab + i))
selected_symbols[nsyms++] = symtab[i];
}
strtab = addr + st->stroff;
strsize = st->strsize;
for (i = 0 ; i < nsyms ; i++) {
if (selected_symbols[i].n_un.n_strx == 0)
selected_symbols[i].n_un.n_name = "";
else if (selected_symbols[i].n_un.n_strx < 0 ||
selected_symbols[i].n_un.n_strx > strsize)
selected_symbols[i].n_un.n_name = "bad string index";
else
selected_symbols[i].n_un.n_name =
selected_symbols[i].n_un.n_strx + strtab;
if (verbose) {
fprintf (stdout, "%8x %s\n",
(unsigned int) selected_symbols[i].n_value,
selected_symbols[i].n_un.n_name);
}
}
rsym_doit2 (selected_symbols, nsyms, outfile);
if (vm_deallocate (mach_task_self (),
(vm_address_t) selected_symbols, s) != KERN_SUCCESS) {
fprintf (stderr, "warning: failed to free memory\n");
}
if (vm_deallocate (mach_task_self (),
(vm_address_t) addr, (vm_size_t) size) != KERN_SUCCESS) {
fprintf (stderr, "warning: failed to deallocate mapped file\n");
}
close (fd);
}
int main (int argc, char **argv, char **envp)
{
int ch;
while ((ch = getopt (argc, argv, "-v")) != -1) {
if (ch == 'v')
verbose = 1;
}
argc -= optind;
argv += optind;
if (argc < 2) {
fprintf (stderr, "usage: rsym [-v(erbose)] <infile> <outfile>\n");
exit (1);
}
rsym_doit1 (argv[0], argv[1]);
return 0;
}
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