5e6220d9d0
longer includes machine/elf.h. * consumers of elf.h now use the minimalist elf header possible. This change is motivated by Binutils 2.11.0 and too much clashing over our base elf headers and the Binutils elf headers.
551 lines
16 KiB
C
551 lines
16 KiB
C
/*
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* Copyright (C) 1996-1997 John D. Polstra. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN D. POLSTRA AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL JOHN D. POLSTRA OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <assert.h>
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#include <ctype.h>
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#include <err.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <machine/elf.h>
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#define FREEBSD_AOUT
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#include <a.out.h>
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#include <link.h>
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#include <stab.h>
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#define PAGE_SIZE 4096 /* i386 specific */
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#ifndef N_SETA
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#define N_SETA 0x14 /* Absolute set element symbol */
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#endif /* This is input to LD, in a .o file. */
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#ifndef N_SETT
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#define N_SETT 0x16 /* Text set element symbol */
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#endif /* This is input to LD, in a .o file. */
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#ifndef N_SETD
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#define N_SETD 0x18 /* Data set element symbol */
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#endif /* This is input to LD, in a .o file. */
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#ifndef N_SETB
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#define N_SETB 0x1A /* Bss set element symbol */
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#endif /* This is input to LD, in a .o file. */
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#ifndef N_SETV
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#define N_SETV 0x1C /* Pointer to set vector in data area. */
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#endif /* This is output from LD. */
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#ifdef STANDALONE
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static
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#endif
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void dump_file(const char *);
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static void dump_rels(const char *, const struct relocation_info *,
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unsigned long, const char *(*)(unsigned long), unsigned char *);
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static void dump_segs();
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static void dump_sods();
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static void dump_sym(const struct nlist *);
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static void dump_syms();
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static void dump_rtsyms();
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static const char *rtsym_name(unsigned long);
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static const char *sym_name(unsigned long);
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#ifdef STANDALONE
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static
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#endif
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int error_count;
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/*
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* Variables ending in _base are pointers to things in our address space,
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* i.e., in the file itself.
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*
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* Variables ending in _addr are adjusted according to where things would
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* actually appear in memory if the file were loaded.
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*/
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static const char *file_base;
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static const char *text_base;
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static const char *data_base;
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static const struct relocation_info *rel_base;
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static const struct nlist *sym_base;
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static const char *str_base;
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static const struct relocation_info *rtrel_base;
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static const struct nzlist *rtsym_base;
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static const char *rtstr_base;
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static const struct exec *ex;
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static const struct _dynamic *dyn;
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static const struct section_dispatch_table *sdt;
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static const char *text_addr;
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static const char *data_addr;
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static unsigned long rel_count;
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static unsigned long sym_count;
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static unsigned long rtrel_count;
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static unsigned long rtsym_count;
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/* Dynamically allocated flags, 1 byte per symbol, to record whether each
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symbol was referenced by a relocation entry. */
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static unsigned char *sym_used;
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static unsigned char *rtsym_used;
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static unsigned long origin; /* What values are relocated relative to */
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#ifdef STANDALONE
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int
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main(int argc, char *argv[])
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{
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int i;
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for (i = 1; i < argc; ++i)
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dump_file(argv[i]);
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return error_count == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
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}
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#endif
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#ifdef STANDALONE
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static
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#endif
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void
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dump_file(const char *fname)
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{
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int fd;
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struct stat sb;
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caddr_t objbase;
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if (stat(fname, &sb) == -1) {
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warnx("cannot stat \"%s\"", fname);
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++error_count;
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return;
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}
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if ((sb.st_mode & S_IFMT) != S_IFREG) {
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warnx("\"%s\" is not a regular file", fname);
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++error_count;
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return;
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}
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if ((fd = open(fname, O_RDONLY, 0)) == -1) {
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warnx("cannot open \"%s\"", fname);
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++error_count;
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return;
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}
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objbase = mmap(0, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
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if (objbase == (caddr_t) -1) {
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warnx("cannot mmap \"%s\"", fname);
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++error_count;
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close(fd);
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return;
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}
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close(fd);
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file_base = (const char *) objbase; /* Makes address arithmetic easier */
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if (IS_ELF(*(Elf32_Ehdr*) file_base)) {
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warnx("%s: this is an ELF program; use objdump to examine", fname);
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++error_count;
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munmap(objbase, sb.st_size);
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close(fd);
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return;
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}
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ex = (const struct exec *) file_base;
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printf("%s: a_midmag = 0x%lx\n", fname, ex->a_midmag);
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printf(" magic = 0x%lx = 0%lo, netmagic = 0x%lx = 0%lo\n",
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N_GETMAGIC(*ex), N_GETMAGIC(*ex),
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N_GETMAGIC_NET(*ex), N_GETMAGIC_NET(*ex));
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if (N_BADMAG(*ex)) {
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warnx("%s: bad magic number", fname);
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++error_count;
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munmap(objbase, sb.st_size);
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return;
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}
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printf(" a_text = 0x%lx\n", ex->a_text);
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printf(" a_data = 0x%lx\n", ex->a_data);
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printf(" a_bss = 0x%lx\n", ex->a_bss);
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printf(" a_syms = 0x%lx\n", ex->a_syms);
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printf(" a_entry = 0x%lx\n", ex->a_entry);
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printf(" a_trsize = 0x%lx\n", ex->a_trsize);
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printf(" a_drsize = 0x%lx\n", ex->a_drsize);
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text_base = file_base + N_TXTOFF(*ex);
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data_base = file_base + N_DATOFF(*ex);
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rel_base = (const struct relocation_info *) (file_base + N_RELOFF(*ex));
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sym_base = (const struct nlist *) (file_base + N_SYMOFF(*ex));
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str_base = file_base + N_STROFF(*ex);
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rel_count = (ex->a_trsize + ex->a_drsize) / sizeof rel_base[0];
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assert(rel_count * sizeof rel_base[0] == ex->a_trsize + ex->a_drsize);
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sym_count = ex->a_syms / sizeof sym_base[0];
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assert(sym_count * sizeof sym_base[0] == ex->a_syms);
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if (sym_count != 0) {
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sym_used = (unsigned char *) calloc(sym_count, sizeof(unsigned char));
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assert(sym_used != NULL);
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}
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printf(" Entry = 0x%lx\n", ex->a_entry);
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printf(" Text offset = %x, address = %lx\n", N_TXTOFF(*ex),
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N_TXTADDR(*ex));
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printf(" Data offset = %lx, address = %lx\n", N_DATOFF(*ex),
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N_DATADDR(*ex));
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/*
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* In an executable program file, everything is relocated relative to
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* the assumed run-time load address, i.e., N_TXTADDR(*ex), i.e., 0x1000.
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*
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* In a shared library file, everything is relocated relative to the
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* start of the file, i.e., N_TXTOFF(*ex), i.e., 0.
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*
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* The way to tell the difference is by looking at ex->a_entry. If it
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* is >= 0x1000, then we have an executable program. Otherwise, we
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* have a shared library.
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*
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* When a program is executed, the entire file is mapped into memory,
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* including the a.out header and so forth. But it is not mapped at
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* address 0; rather it is mapped at address 0x1000. The first page
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* of the user's address space is left unmapped in order to catch null
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* pointer dereferences.
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*
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* In this program, when we map in an executable program, we have to
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* simulate the empty page by decrementing our assumed base address by
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* a pagesize.
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*/
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text_addr = text_base;
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data_addr = data_base;
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origin = 0;
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if (ex->a_entry >= PAGE_SIZE) { /* Executable, not a shared library */
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/*
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* The fields in the object have already been relocated on the
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* assumption that the object will be loaded at N_TXTADDR(*ex).
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* We have to compensate for that.
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*/
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text_addr -= PAGE_SIZE;
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data_addr -= PAGE_SIZE;
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origin = PAGE_SIZE;
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printf(" Program, origin = %lx\n", origin);
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} else if (N_GETFLAG(*ex) & EX_DYNAMIC)
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printf(" Shared library, origin = %lx\n", origin);
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else
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printf(" Object file, origin = %lx\n", origin);
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if (N_GETFLAG(*ex) & EX_DYNAMIC) {
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dyn = (const struct _dynamic *) data_base;
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printf(" Dynamic version = %d\n", dyn->d_version);
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sdt = (const struct section_dispatch_table *)
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(text_addr + (unsigned long) dyn->d_un.d_sdt);
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rtrel_base =
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(const struct relocation_info *) (text_addr + sdt->sdt_rel);
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rtrel_count = (sdt->sdt_hash - sdt->sdt_rel) / sizeof rtrel_base[0];
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assert(rtrel_count * sizeof rtrel_base[0] ==
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sdt->sdt_hash - sdt->sdt_rel);
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rtsym_base = (const struct nzlist *) (text_addr + sdt->sdt_nzlist);
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rtsym_count = (sdt->sdt_strings - sdt->sdt_nzlist) /
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sizeof rtsym_base[0];
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assert(rtsym_count * sizeof rtsym_base[0] ==
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sdt->sdt_strings - sdt->sdt_nzlist);
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if (rtsym_count != 0) {
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rtsym_used = (unsigned char *) calloc(rtsym_count,
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sizeof(unsigned char));
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assert(rtsym_used != NULL);
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}
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rtstr_base = text_addr + sdt->sdt_strings;
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}
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dump_segs();
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dump_sods();
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dump_rels("Relocations", rel_base, rel_count, sym_name, sym_used);
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dump_syms();
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dump_rels("Run-time relocations", rtrel_base, rtrel_count, rtsym_name,
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rtsym_used);
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dump_rtsyms();
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if (rtsym_used != NULL) {
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free(rtsym_used);
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rtsym_used = NULL;
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}
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if (sym_used != NULL) {
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free(sym_used);
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sym_used = NULL;
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}
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munmap(objbase, sb.st_size);
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}
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static void
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dump_rels(const char *label, const struct relocation_info *base,
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unsigned long count, const char *(*name)(unsigned long),
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unsigned char *sym_used_flags)
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{
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unsigned long i;
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printf(" %s:\n", label);
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for (i = 0; i < count; ++i) {
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const struct relocation_info *r = &base[i];
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unsigned int size;
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char contents[16];
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size = 1u << r->r_length;
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if (origin <= r->r_address
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&& r->r_address < origin + ex->a_text + ex->a_data
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&& 1 <= size && size <= 4) {
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/*
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* XXX - This can cause unaligned accesses. OK for the
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* i386, not so for other architectures.
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*/
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switch (size) {
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case 1:
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snprintf(contents, sizeof contents, " [%02x]",
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*(unsigned char *)(text_addr + r->r_address));
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break;
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case 2:
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snprintf(contents, sizeof contents, " [%04x]",
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*(unsigned short *)(text_addr + r->r_address));
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break;
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case 4:
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snprintf(contents, sizeof contents, "[%08lx]",
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*(unsigned long *)(text_addr + r->r_address));
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break;
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}
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} else
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snprintf(contents, sizeof contents, " ");
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printf(" %6lu %8x/%u %s %c%c%c%c%c%c", i,
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r->r_address, size,
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contents,
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r->r_extern ? 'e' : '-',
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r->r_jmptable ? 'j' : '-',
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r->r_relative ? 'r' : '-',
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r->r_baserel ? 'b' : '-',
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r->r_pcrel ? 'p' : '-',
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r->r_copy ? 'c' : '-');
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if (r->r_extern || r->r_baserel || r->r_jmptable || r->r_copy) {
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printf(" %4u %s", r->r_symbolnum, name(r->r_symbolnum));
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sym_used_flags[r->r_symbolnum] = 1;
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}
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printf("\n");
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}
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}
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static void
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dump_rtsyms()
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{
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unsigned long i;
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printf(" Run-time symbols:\n");
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for (i = 0; i < rtsym_count; ++i) {
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printf(" %6lu%c ", i, rtsym_used[i] ? '*' : ' ');
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dump_sym(&rtsym_base[i].nlist);
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printf("/%-5ld %s\n", rtsym_base[i].nz_size, rtsym_name(i));
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}
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}
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static void
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dump_segs()
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{
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printf(" Text segment starts at address %lx\n", origin + N_TXTOFF(*ex));
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if (N_GETFLAG(*ex) & EX_DYNAMIC) {
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printf(" rel starts at %lx\n", sdt->sdt_rel);
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printf(" hash starts at %lx\n", sdt->sdt_hash);
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printf(" nzlist starts at %lx\n", sdt->sdt_nzlist);
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printf(" strings starts at %lx\n", sdt->sdt_strings);
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}
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printf(" Data segment starts at address %lx\n", origin + N_DATOFF(*ex));
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if (N_GETFLAG(*ex) & EX_DYNAMIC) {
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printf(" _dynamic starts at %lx\n", origin + N_DATOFF(*ex));
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printf(" so_debug starts at %lx\n", (unsigned long) dyn->d_debug);
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printf(" sdt starts at %lx\n", (unsigned long) dyn->d_un.d_sdt);
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printf(" got starts at %lx\n", sdt->sdt_got);
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printf(" plt starts at %lx\n", sdt->sdt_plt);
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printf(" rest of stuff starts at %lx\n",
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sdt->sdt_plt + sdt->sdt_plt_sz);
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}
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}
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static void
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dump_sods()
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{
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long sod_offset;
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long paths_offset;
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if (dyn == NULL) /* Not a shared object */
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return;
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sod_offset = sdt->sdt_sods;
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printf(" Shared object dependencies:\n");
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while (sod_offset != 0) {
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const struct sod *sodp = (const struct sod *) (text_addr + sod_offset);
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const char *name = (const char *) (text_addr + sodp->sod_name);
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if (sodp->sod_library)
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printf(" -l%-16s version %d.%d\n", name, sodp->sod_major,
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sodp->sod_minor);
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else
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printf(" %s\n", name);
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sod_offset = sodp->sod_next;
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}
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paths_offset = sdt->sdt_paths;
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printf(" Shared object additional paths:\n");
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if (paths_offset != 0) {
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char *path = (char *)(text_addr + paths_offset);
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printf(" %s\n", path);
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} else {
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printf(" (none)\n");
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}
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}
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static void
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dump_sym(const struct nlist *np)
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{
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char type[8];
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char aux[8];
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char weak;
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char *p;
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switch (np->n_type & ~N_EXT) {
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case N_UNDF: strcpy(type, "undf"); break;
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case N_ABS: strcpy(type, "abs"); break;
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case N_TEXT: strcpy(type, "text"); break;
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case N_DATA: strcpy(type, "data"); break;
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case N_BSS: strcpy(type, "bss"); break;
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case N_INDR: strcpy(type, "indr"); break;
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case N_SIZE: strcpy(type, "size"); break;
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case N_COMM: strcpy(type, "comm"); break;
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case N_SETA: strcpy(type, "seta"); break;
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case N_SETT: strcpy(type, "sett"); break;
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case N_SETD: strcpy(type, "setd"); break;
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case N_SETB: strcpy(type, "setb"); break;
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case N_SETV: strcpy(type, "setv"); break;
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case N_FN: strcpy(type, np->n_type&N_EXT ? "fn" : "warn"); break;
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case N_GSYM: strcpy(type, "gsym"); break;
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case N_FNAME: strcpy(type, "fname"); break;
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case N_FUN: strcpy(type, "fun"); break;
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case N_STSYM: strcpy(type, "stsym"); break;
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case N_LCSYM: strcpy(type, "lcsym"); break;
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case N_MAIN: strcpy(type, "main"); break;
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case N_PC: strcpy(type, "pc"); break;
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case N_RSYM: strcpy(type, "rsym"); break;
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case N_SLINE: strcpy(type, "sline"); break;
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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()
|
|
{
|
|
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;
|
|
}
|