FreeBSD-5.3/usr.bin/ldd/sods.c
/*
* Copyright (C) 1996-1997 John D. Polstra. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY JOHN D. POLSTRA AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL JOHN D. POLSTRA OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/usr.bin/ldd/sods.c,v 1.17 2004/06/29 21:13:15 dwmalone Exp $");
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <machine/elf.h>
#include <arpa/inet.h>
#include <a.out.h>
#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <sys/link_aout.h>
#include <stab.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "extern.h"
#define PAGE_SIZE 4096 /* i386 specific */
#ifndef N_SETA
#define N_SETA 0x14 /* Absolute set element symbol */
#endif /* This is input to LD, in a .o file. */
#ifndef N_SETT
#define N_SETT 0x16 /* Text set element symbol */
#endif /* This is input to LD, in a .o file. */
#ifndef N_SETD
#define N_SETD 0x18 /* Data set element symbol */
#endif /* This is input to LD, in a .o file. */
#ifndef N_SETB
#define N_SETB 0x1A /* Bss set element symbol */
#endif /* This is input to LD, in a .o file. */
#ifndef N_SETV
#define N_SETV 0x1C /* Pointer to set vector in data area. */
#endif /* This is output from LD. */
#ifdef STANDALONE
static
#endif
static void dump_rels(const char *, const struct relocation_info *,
unsigned long, const char *(*)(unsigned long), unsigned char *);
static void dump_segs(void);
static void dump_sods(void);
static void dump_sym(const struct nlist *);
static void dump_syms(void);
static void dump_rtsyms(void);
static const char *rtsym_name(unsigned long);
static const char *sym_name(unsigned long);
#ifdef STANDALONE
static
#endif
int error_count;
/*
* Variables ending in _base are pointers to things in our address space,
* i.e., in the file itself.
*
* Variables ending in _addr are adjusted according to where things would
* actually appear in memory if the file were loaded.
*/
static const char *file_base;
static const char *text_base;
static const char *data_base;
static const struct relocation_info *rel_base;
static const struct nlist *sym_base;
static const char *str_base;
static const struct relocation_info *rtrel_base;
static const struct nzlist *rtsym_base;
static const char *rtstr_base;
static const struct exec *ex;
static const struct _dynamic *dyn;
static const struct section_dispatch_table *sdt;
static const char *text_addr;
static const char *data_addr;
static unsigned long rel_count;
static unsigned long sym_count;
static unsigned long rtrel_count;
static unsigned long rtsym_count;
/* Dynamically allocated flags, 1 byte per symbol, to record whether each
symbol was referenced by a relocation entry. */
static unsigned char *sym_used;
static unsigned char *rtsym_used;
static unsigned long origin; /* What values are relocated relative to */
#ifdef STANDALONE
int
main(int argc, char *argv[])
{
int i;
for (i = 1; i < argc; ++i)
dump_file(argv[i]);
return error_count == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
}
#endif
#ifdef STANDALONE
static
#endif
void
dump_file(const char *fname)
{
int fd;
struct stat sb;
caddr_t objbase;
if (stat(fname, &sb) == -1) {
warnx("cannot stat \"%s\"", fname);
++error_count;
return;
}
if ((sb.st_mode & S_IFMT) != S_IFREG) {
warnx("\"%s\" is not a regular file", fname);
++error_count;
return;
}
if ((fd = open(fname, O_RDONLY, 0)) == -1) {
warnx("cannot open \"%s\"", fname);
++error_count;
return;
}
objbase = mmap(0, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (objbase == (caddr_t) -1) {
warnx("cannot mmap \"%s\"", fname);
++error_count;
close(fd);
return;
}
close(fd);
file_base = (const char *) objbase; /* Makes address arithmetic easier */
if (IS_ELF(*(const Elf32_Ehdr*) file_base)) {
warnx("%s: this is an ELF program; use objdump to examine", fname);
++error_count;
munmap(objbase, sb.st_size);
close(fd);
return;
}
ex = (const struct exec *) file_base;
printf("%s: a_midmag = 0x%lx\n", fname, (long)ex->a_midmag);
printf(" magic = 0x%lx = 0%lo, netmagic = 0x%lx = 0%lo\n",
(long)N_GETMAGIC(*ex), (long)N_GETMAGIC(*ex),
(long)N_GETMAGIC_NET(*ex), (long)N_GETMAGIC_NET(*ex));
if (N_BADMAG(*ex)) {
warnx("%s: bad magic number", fname);
++error_count;
munmap(objbase, sb.st_size);
return;
}
printf(" a_text = 0x%lx\n", (long)ex->a_text);
printf(" a_data = 0x%lx\n", (long)ex->a_data);
printf(" a_bss = 0x%lx\n", (long)ex->a_bss);
printf(" a_syms = 0x%lx\n", (long)ex->a_syms);
printf(" a_entry = 0x%lx\n", (long)ex->a_entry);
printf(" a_trsize = 0x%lx\n", (long)ex->a_trsize);
printf(" a_drsize = 0x%lx\n", (long)ex->a_drsize);
text_base = file_base + N_TXTOFF(*ex);
data_base = file_base + N_DATOFF(*ex);
rel_base = (const struct relocation_info *) (file_base + N_RELOFF(*ex));
sym_base = (const struct nlist *) (file_base + N_SYMOFF(*ex));
str_base = file_base + N_STROFF(*ex);
rel_count = (ex->a_trsize + ex->a_drsize) / sizeof rel_base[0];
assert(rel_count * sizeof rel_base[0] == ex->a_trsize + ex->a_drsize);
sym_count = ex->a_syms / sizeof sym_base[0];
assert(sym_count * sizeof sym_base[0] == ex->a_syms);
if (sym_count != 0) {
sym_used = (unsigned char *) calloc(sym_count, sizeof(unsigned char));
assert(sym_used != NULL);
}
printf(" Entry = 0x%lx\n", (long)ex->a_entry);
printf(" Text offset = %x, address = %lx\n", N_TXTOFF(*ex),
(long)N_TXTADDR(*ex));
printf(" Data offset = %lx, address = %lx\n", (long)N_DATOFF(*ex),
(long)N_DATADDR(*ex));
/*
* In an executable program file, everything is relocated relative to
* the assumed run-time load address, i.e., N_TXTADDR(*ex), i.e., 0x1000.
*
* In a shared library file, everything is relocated relative to the
* start of the file, i.e., N_TXTOFF(*ex), i.e., 0.
*
* The way to tell the difference is by looking at ex->a_entry. If it
* is >= 0x1000, then we have an executable program. Otherwise, we
* have a shared library.
*
* When a program is executed, the entire file is mapped into memory,
* including the a.out header and so forth. But it is not mapped at
* address 0; rather it is mapped at address 0x1000. The first page
* of the user's address space is left unmapped in order to catch null
* pointer dereferences.
*
* In this program, when we map in an executable program, we have to
* simulate the empty page by decrementing our assumed base address by
* a pagesize.
*/
text_addr = text_base;
data_addr = data_base;
origin = 0;
if (ex->a_entry >= PAGE_SIZE) { /* Executable, not a shared library */
/*
* The fields in the object have already been relocated on the
* assumption that the object will be loaded at N_TXTADDR(*ex).
* We have to compensate for that.
*/
text_addr -= PAGE_SIZE;
data_addr -= PAGE_SIZE;
origin = PAGE_SIZE;
printf(" Program, origin = %lx\n", origin);
} else if (N_GETFLAG(*ex) & EX_DYNAMIC)
printf(" Shared library, origin = %lx\n", origin);
else
printf(" Object file, origin = %lx\n", origin);
if (N_GETFLAG(*ex) & EX_DYNAMIC) {
dyn = (const struct _dynamic *) data_base;
printf(" Dynamic version = %d\n", dyn->d_version);
sdt = (const struct section_dispatch_table *)
(text_addr + (unsigned long) dyn->d_un.d_sdt);
rtrel_base =
(const struct relocation_info *) (text_addr + sdt->sdt_rel);
rtrel_count = (sdt->sdt_hash - sdt->sdt_rel) / sizeof rtrel_base[0];
assert(rtrel_count * sizeof rtrel_base[0] ==
(size_t)(sdt->sdt_hash - sdt->sdt_rel));
rtsym_base = (const struct nzlist *) (text_addr + sdt->sdt_nzlist);
rtsym_count = (sdt->sdt_strings - sdt->sdt_nzlist) /
sizeof rtsym_base[0];
assert(rtsym_count * sizeof rtsym_base[0] ==
(size_t)(sdt->sdt_strings - sdt->sdt_nzlist));
if (rtsym_count != 0) {
rtsym_used = (unsigned char *) calloc(rtsym_count,
sizeof(unsigned char));
assert(rtsym_used != NULL);
}
rtstr_base = text_addr + sdt->sdt_strings;
}
dump_segs();
dump_sods();
dump_rels("Relocations", rel_base, rel_count, sym_name, sym_used);
dump_syms();
dump_rels("Run-time relocations", rtrel_base, rtrel_count, rtsym_name,
rtsym_used);
dump_rtsyms();
if (rtsym_used != NULL) {
free(rtsym_used);
rtsym_used = NULL;
}
if (sym_used != NULL) {
free(sym_used);
sym_used = NULL;
}
munmap(objbase, sb.st_size);
}
static void
dump_rels(const char *label, const struct relocation_info *base,
unsigned long count, const char *(*name)(unsigned long),
unsigned char *sym_used_flags)
{
unsigned long i;
printf(" %s:\n", label);
for (i = 0; i < count; ++i) {
const struct relocation_info *r = &base[i];
unsigned int size;
char contents[16];
size = 1u << r->r_length;
if (origin <= (unsigned long)r->r_address
&& (unsigned long)r->r_address < origin + ex->a_text + ex->a_data
&& 1 <= size && size <= 4) {
/*
* XXX - This can cause unaligned accesses. OK for the
* i386, not so for other architectures.
*/
switch (size) {
case 1:
snprintf(contents, sizeof contents, " [%02x]",
*(unsigned const char *)(text_addr + r->r_address));
break;
case 2:
snprintf(contents, sizeof contents, " [%04x]",
*(unsigned const short *)(text_addr + r->r_address));
break;
case 4:
snprintf(contents, sizeof contents, "[%08lx]",
*(unsigned const long *)(text_addr + r->r_address));
break;
}
} else
snprintf(contents, sizeof contents, " ");
printf(" %6lu %8x/%u %s %c%c%c%c%c%c", i,
r->r_address, size,
contents,
r->r_extern ? 'e' : '-',
r->r_jmptable ? 'j' : '-',
r->r_relative ? 'r' : '-',
r->r_baserel ? 'b' : '-',
r->r_pcrel ? 'p' : '-',
r->r_copy ? 'c' : '-');
if (r->r_extern || r->r_baserel || r->r_jmptable || r->r_copy) {
printf(" %4u %s", r->r_symbolnum, name(r->r_symbolnum));
sym_used_flags[r->r_symbolnum] = 1;
}
printf("\n");
}
}
static void
dump_rtsyms(void)
{
unsigned long i;
printf(" Run-time symbols:\n");
for (i = 0; i < rtsym_count; ++i) {
printf(" %6lu%c ", i, rtsym_used[i] ? '*' : ' ');
dump_sym(&rtsym_base[i].nlist);
printf("/%-5ld %s\n", rtsym_base[i].nz_size, rtsym_name(i));
}
}
static void
dump_segs(void)
{
printf(" Text segment starts at address %lx\n", origin + N_TXTOFF(*ex));
if (N_GETFLAG(*ex) & EX_DYNAMIC) {
printf(" rel starts at %lx\n", sdt->sdt_rel);
printf(" hash starts at %lx\n", sdt->sdt_hash);
printf(" nzlist starts at %lx\n", sdt->sdt_nzlist);
printf(" strings starts at %lx\n", sdt->sdt_strings);
}
printf(" Data segment starts at address %lx\n", origin + N_DATOFF(*ex));
if (N_GETFLAG(*ex) & EX_DYNAMIC) {
printf(" _dynamic starts at %lx\n", origin + N_DATOFF(*ex));
printf(" so_debug starts at %lx\n", (unsigned long) dyn->d_debug);
printf(" sdt starts at %lx\n", (unsigned long) dyn->d_un.d_sdt);
printf(" got starts at %lx\n", sdt->sdt_got);
printf(" plt starts at %lx\n", sdt->sdt_plt);
printf(" rest of stuff starts at %lx\n",
sdt->sdt_plt + sdt->sdt_plt_sz);
}
}
static void
dump_sods(void)
{
long sod_offset;
long paths_offset;
if (dyn == NULL) /* Not a shared object */
return;
sod_offset = sdt->sdt_sods;
printf(" Shared object dependencies:\n");
while (sod_offset != 0) {
const struct sod *sodp = (const struct sod *) (text_addr + sod_offset);
const char *name = (const char *) (text_addr + sodp->sod_name);
if (sodp->sod_library)
printf(" -l%-16s version %d.%d\n", name, sodp->sod_major,
sodp->sod_minor);
else
printf(" %s\n", name);
sod_offset = sodp->sod_next;
}
paths_offset = sdt->sdt_paths;
printf(" Shared object additional paths:\n");
if (paths_offset != 0) {
printf(" %s\n", (const char *)(text_addr + paths_offset));
} else {
printf(" (none)\n");
}
}
static void
dump_sym(const struct nlist *np)
{
char type[8];
char aux[8];
char weak;
char *p;
switch (np->n_type & ~N_EXT) {
case N_UNDF: strcpy(type, "undf"); break;
case N_ABS: strcpy(type, "abs"); break;
case N_TEXT: strcpy(type, "text"); break;
case N_DATA: strcpy(type, "data"); break;
case N_BSS: strcpy(type, "bss"); break;
case N_INDR: strcpy(type, "indr"); break;
case N_SIZE: strcpy(type, "size"); break;
case N_COMM: strcpy(type, "comm"); break;
case N_SETA: strcpy(type, "seta"); break;
case N_SETT: strcpy(type, "sett"); break;
case N_SETD: strcpy(type, "setd"); break;
case N_SETB: strcpy(type, "setb"); break;
case N_SETV: strcpy(type, "setv"); break;
case N_FN: strcpy(type, np->n_type&N_EXT ? "fn" : "warn"); break;
case N_GSYM: strcpy(type, "gsym"); break;
case N_FNAME: strcpy(type, "fname"); break;
case N_FUN: strcpy(type, "fun"); break;
case N_STSYM: strcpy(type, "stsym"); break;
case N_LCSYM: strcpy(type, "lcsym"); break;
case N_MAIN: strcpy(type, "main"); break;
case N_PC: strcpy(type, "pc"); break;
case N_RSYM: strcpy(type, "rsym"); break;
case N_SLINE: strcpy(type, "sline"); break;
case N_DSLINE: strcpy(type, "dsline"); break;
case N_BSLINE: strcpy(type, "bsline"); break;
case N_SSYM: strcpy(type, "ssym"); break;
case N_SO: strcpy(type, "so"); break;
case N_LSYM: strcpy(type, "lsym"); break;
case N_BINCL: strcpy(type, "bincl"); break;
case N_SOL: strcpy(type, "sol"); break;
case N_PSYM: strcpy(type, "psym"); break;
case N_EINCL: strcpy(type, "eincl"); break;
case N_ENTRY: strcpy(type, "entry"); break;
case N_LBRAC: strcpy(type, "lbrac"); break;
case N_EXCL: strcpy(type, "excl"); break;
case N_RBRAC: strcpy(type, "rbrac"); break;
case N_BCOMM: strcpy(type, "bcomm"); break;
case N_ECOMM: strcpy(type, "ecomm"); break;
case N_ECOML: strcpy(type, "ecoml"); break;
case N_LENG: strcpy(type, "leng"); break;
default:
snprintf(type, sizeof type, "%#02x", np->n_type);
break;
}
if (np->n_type & N_EXT && type[0] != '0')
for (p = type; *p != '\0'; ++p)
*p = toupper(*p);
switch (N_AUX(np)) {
case 0: strcpy(aux, ""); break;
case AUX_OBJECT: strcpy(aux, "objt"); break;
case AUX_FUNC: strcpy(aux, "func"); break;
default: snprintf(aux, sizeof aux, "%#01x", N_AUX(np)); break;
}
weak = N_BIND(np) == BIND_WEAK ? 'w' : ' ';
printf("%c%-6s %-4s %8lx", weak, type, aux, np->n_value);
}
static void
dump_syms(void)
{
unsigned long i;
printf(" Symbols:\n");
for (i = 0; i < sym_count; ++i) {
printf(" %6lu%c ", i, sym_used[i] ? '*' : ' ');
dump_sym(&sym_base[i]);
printf(" %s\n", sym_name(i));
}
}
static const char *
rtsym_name(unsigned long n)
{
assert(n < rtsym_count);
if (rtsym_base[n].nz_strx == 0)
return "";
return rtstr_base + rtsym_base[n].nz_strx;
}
static const char *
sym_name(unsigned long n)
{
assert(n < sym_count);
if (sym_base[n].n_un.n_strx == 0)
return "";
return str_base + sym_base[n].n_un.n_strx;
}