mirror of
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a1e5be4482
to cast to long before printing. While I'm here, raise WARNS to 6.
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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.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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#include <arpa/inet.h>
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#include <a.out.h>
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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 <sys/link_aout.h>
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#include <stab.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "extern.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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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(void);
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static void dump_sods(void);
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static void dump_sym(const struct nlist *);
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static void dump_syms(void);
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static void dump_rtsyms(void);
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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(*(const 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, (long)ex->a_midmag);
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printf(" magic = 0x%lx = 0%lo, netmagic = 0x%lx = 0%lo\n",
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(long)N_GETMAGIC(*ex), (long)N_GETMAGIC(*ex),
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(long)N_GETMAGIC_NET(*ex), (long)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", (long)ex->a_text);
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printf(" a_data = 0x%lx\n", (long)ex->a_data);
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printf(" a_bss = 0x%lx\n", (long)ex->a_bss);
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printf(" a_syms = 0x%lx\n", (long)ex->a_syms);
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printf(" a_entry = 0x%lx\n", (long)ex->a_entry);
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printf(" a_trsize = 0x%lx\n", (long)ex->a_trsize);
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printf(" a_drsize = 0x%lx\n", (long)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", (long)ex->a_entry);
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printf(" Text offset = %x, address = %lx\n", N_TXTOFF(*ex),
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(long)N_TXTADDR(*ex));
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printf(" Data offset = %lx, address = %lx\n", (long)N_DATOFF(*ex),
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(long)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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(size_t)(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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(size_t)(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 <= (unsigned long)r->r_address
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&& (unsigned long)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 const 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 const 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 const 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(void)
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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(void)
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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(void)
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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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printf(" %s\n", (const char *)(text_addr + paths_offset));
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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;
|
|
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;
|
|
}
|