467 lines
10 KiB
C
467 lines
10 KiB
C
/* $NetBSD: readelf.c,v 1.6 2000/05/14 22:53:38 christos Exp $ */
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#include "file.h"
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#ifdef BUILTIN_ELF
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#include <sys/types.h>
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#include <string.h>
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#include <stdio.h>
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#include <ctype.h>
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#include <stdlib.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <errno.h>
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#include "readelf.h"
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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FILE_RCSID("@(#)Id: readelf.c,v 1.12 2000/04/11 02:32:35 christos Exp ")
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#else
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__RCSID("$NetBSD: readelf.c,v 1.6 2000/05/14 22:53:38 christos Exp $");
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#endif
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#endif
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#ifdef ELFCORE
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static void dophn_core __P((int, int, int, off_t, int, size_t));
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#endif
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static void dophn_exec __P((int, int, int, off_t, int, size_t));
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static void doshn __P((int, int, int, off_t, int, size_t));
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static uint16_t getu16 __P((int, int));
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static uint32_t getu32 __P((int, uint32_t));
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static uint64_t getu64 __P((int, uint64_t));
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static uint16_t
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getu16(swap, value)
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int swap;
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uint16_t value;
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{
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union {
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uint16_t ui;
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char c[2];
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} retval, tmpval;
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if (swap) {
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tmpval.ui = value;
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retval.c[0] = tmpval.c[1];
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retval.c[1] = tmpval.c[0];
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return retval.ui;
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} else
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return value;
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}
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static uint32_t
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getu32(swap, value)
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int swap;
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uint32_t value;
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{
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union {
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uint32_t ui;
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char c[4];
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} retval, tmpval;
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if (swap) {
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tmpval.ui = value;
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retval.c[0] = tmpval.c[3];
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retval.c[1] = tmpval.c[2];
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retval.c[2] = tmpval.c[1];
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retval.c[3] = tmpval.c[0];
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return retval.ui;
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} else
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return value;
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}
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static uint64_t
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getu64(swap, value)
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int swap;
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uint64_t value;
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{
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union {
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uint64_t ui;
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char c[8];
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} retval, tmpval;
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if (swap) {
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tmpval.ui = value;
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retval.c[0] = tmpval.c[7];
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retval.c[1] = tmpval.c[6];
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retval.c[2] = tmpval.c[5];
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retval.c[3] = tmpval.c[4];
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retval.c[4] = tmpval.c[3];
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retval.c[5] = tmpval.c[2];
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retval.c[6] = tmpval.c[1];
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retval.c[7] = tmpval.c[0];
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return retval.ui;
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} else
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return value;
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}
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#define sh_addr (class == ELFCLASS32 \
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? (void *) &sh32 \
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: (void *) &sh64)
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#define shs_type (class == ELFCLASS32 \
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? getu32(swap, sh32.sh_type) \
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: getu32(swap, sh64.sh_type))
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#define ph_addr (class == ELFCLASS32 \
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? (void *) &ph32 \
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: (void *) &ph64)
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#define ph_type (class == ELFCLASS32 \
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? getu32(swap, ph32.p_type) \
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: getu32(swap, ph64.p_type))
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#define ph_offset (class == ELFCLASS32 \
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? getu32(swap, ph32.p_offset) \
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: getu64(swap, ph64.p_offset))
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#define nh_size (class == ELFCLASS32 \
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? sizeof *nh32 \
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: sizeof *nh64)
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#define nh_type (class == ELFCLASS32 \
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? getu32(swap, nh32->n_type) \
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: getu32(swap, nh64->n_type))
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#define nh_namesz (class == ELFCLASS32 \
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? getu32(swap, nh32->n_namesz) \
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: getu32(swap, nh64->n_namesz))
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#define nh_descsz (class == ELFCLASS32 \
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? getu32(swap, nh32->n_descsz) \
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: getu32(swap, nh64->n_descsz))
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#define prpsoffsets(i) (class == ELFCLASS32 \
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? prpsoffsets32[i] \
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: prpsoffsets64[i])
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static void
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doshn(class, swap, fd, off, num, size)
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int class;
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int swap;
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int fd;
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off_t off;
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int num;
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size_t size;
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{
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Elf32_Shdr sh32;
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Elf64_Shdr sh64;
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if (lseek(fd, off, SEEK_SET) == -1)
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error("lseek failed (%s).\n", strerror(errno));
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for ( ; num; num--) {
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if (read(fd, sh_addr, size) == -1)
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error("read failed (%s).\n", strerror(errno));
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if (shs_type == SHT_SYMTAB /* || shs_type == SHT_DYNSYM */) {
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(void) printf (", not stripped");
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return;
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}
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}
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(void) printf (", stripped");
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}
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/*
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* Look through the program headers of an executable image, searching
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* for a PT_INTERP section; if one is found, it's dynamically linked,
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* otherwise it's statically linked.
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*/
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static void
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dophn_exec(class, swap, fd, off, num, size)
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int class;
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int swap;
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int fd;
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off_t off;
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int num;
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size_t size;
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{
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Elf32_Phdr ph32;
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Elf64_Phdr ph64;
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char *linking_style = "statically";
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char *shared_libraries = "";
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if (lseek(fd, off, SEEK_SET) == -1)
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error("lseek failed (%s).\n", strerror(errno));
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for ( ; num; num--) {
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if (read(fd, ph_addr, size) == -1)
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error("read failed (%s).\n", strerror(errno));
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switch (ph_type) {
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case PT_DYNAMIC:
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linking_style = "dynamically";
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break;
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case PT_INTERP:
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shared_libraries = " (uses shared libs)";
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break;
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}
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}
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printf(", %s linked%s", linking_style, shared_libraries);
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}
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#ifdef ELFCORE
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size_t prpsoffsets32[] = {
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84, /* SunOS 5.x */
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32, /* Linux */
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};
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size_t prpsoffsets64[] = {
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120, /* SunOS 5.x, 64-bit */
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};
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#define NOFFSETS32 (sizeof prpsoffsets32 / sizeof prpsoffsets32[0])
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#define NOFFSETS64 (sizeof prpsoffsets64 / sizeof prpsoffsets64[0])
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#define NOFFSETS (class == ELFCLASS32 ? NOFFSETS32 : NOFFSETS64)
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/*
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* Look through the program headers of an executable image, searching
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* for a PT_NOTE section of type NT_PRPSINFO, with a name "CORE"; if one
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* is found, try looking in various places in its contents for a 16-character
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* string containing only printable characters - if found, that string
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* should be the name of the program that dropped core.
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* Note: right after that 16-character string is, at least in SunOS 5.x
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* (and possibly other SVR4-flavored systems) and Linux, a longer string
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* (80 characters, in 5.x, probably other SVR4-flavored systems, and Linux)
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* containing the start of the command line for that program.
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*/
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static void
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dophn_core(class, swap, fd, off, num, size)
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int class;
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int swap;
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int fd;
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off_t off;
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int num;
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size_t size;
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{
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Elf32_Phdr ph32;
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Elf32_Nhdr *nh32;
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Elf64_Phdr ph64;
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Elf64_Nhdr *nh64;
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size_t offset, noffset, reloffset;
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unsigned char c;
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int i, j;
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char nbuf[BUFSIZ];
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int bufsize;
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for ( ; num; num--) {
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if (lseek(fd, off, SEEK_SET) == -1)
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error("lseek failed (%s).\n", strerror(errno));
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if (read(fd, ph_addr, size) == -1)
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error("read failed (%s).\n", strerror(errno));
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off += size;
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if (ph_type != PT_NOTE)
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continue;
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if (lseek(fd, (off_t) ph_offset, SEEK_SET) == -1)
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error("lseek failed (%s).\n", strerror(errno));
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bufsize = read(fd, nbuf, BUFSIZ);
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if (bufsize == -1)
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error(": " "read failed (%s).\n", strerror(errno));
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offset = 0;
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for (;;) {
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if (offset >= bufsize)
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break;
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if (class == ELFCLASS32)
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nh32 = (Elf32_Nhdr *)&nbuf[offset];
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else
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nh64 = (Elf64_Nhdr *)&nbuf[offset];
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offset += nh_size;
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/*
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* If this note isn't an NT_PRPSINFO note, it's
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* not what we're looking for.
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*/
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if (nh_type != NT_PRPSINFO) {
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offset += nh_namesz;
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offset = ((offset + 3)/4)*4;
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offset += nh_descsz;
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offset = ((offset + 3)/4)*4;
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continue;
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}
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/*
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* Make sure this note has the name "CORE".
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*/
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if (offset + nh_namesz >= bufsize) {
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/*
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* We're past the end of the buffer.
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*/
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break;
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}
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if (nh_namesz != 5
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|| strcmp(&nbuf[offset], "CORE") != 0)
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continue;
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offset += nh_namesz;
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offset = ((offset + 3)/4)*4;
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/*
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* Extract the program name. We assume it to be
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* 16 characters (that's what it is in SunOS 5.x
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* and Linux).
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*
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* Unfortunately, it's at a different offset in
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* SunOS 5.x and Linux, so try multiple offsets.
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* If the characters aren't all printable, reject
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* it.
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*/
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for (i = 0; i < NOFFSETS; i++) {
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reloffset = prpsoffsets(i);
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noffset = offset + reloffset;
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for (j = 0; j < 16;
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j++, noffset++, reloffset++) {
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/*
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* Make sure we're not past the end
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* of the buffer; if we are, just
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* give up.
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*/
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if (noffset >= bufsize)
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return;
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/*
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* Make sure we're not past the
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* end of the contents; if we
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* are, this obviously isn't
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* the right offset.
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*/
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if (reloffset >= nh_descsz)
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goto tryanother;
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c = nbuf[noffset];
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if (c != '\0' && !isprint(c))
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goto tryanother;
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}
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/*
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* Well, that worked.
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*/
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printf(", from '%.16s'",
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&nbuf[offset + prpsoffsets(i)]);
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return;
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tryanother:
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;
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}
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offset += nh_descsz;
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offset = ((offset + 3)/4)*4;
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}
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}
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}
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#endif
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void
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tryelf(fd, buf, nbytes)
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int fd;
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unsigned char *buf;
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int nbytes;
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{
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union {
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int32 l;
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char c[sizeof (int32)];
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} u;
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int class;
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int swap;
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/*
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* ELF executables have multiple section headers in arbitrary
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* file locations and thus file(1) cannot determine it from easily.
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* Instead we traverse thru all section headers until a symbol table
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* one is found or else the binary is stripped.
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*/
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if (buf[EI_MAG0] != ELFMAG0
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|| (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
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|| buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
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return;
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class = buf[4];
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if (class == ELFCLASS32) {
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Elf32_Ehdr elfhdr;
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if (nbytes <= sizeof (Elf32_Ehdr))
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return;
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u.l = 1;
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(void) memcpy(&elfhdr, buf, sizeof elfhdr);
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swap = (u.c[sizeof(long) - 1] + 1) != elfhdr.e_ident[5];
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if (getu16(swap, elfhdr.e_type) == ET_CORE)
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#ifdef ELFCORE
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dophn_core(class, swap,
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fd,
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getu32(swap, elfhdr.e_phoff),
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getu16(swap, elfhdr.e_phnum),
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getu16(swap, elfhdr.e_phentsize));
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#else
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;
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#endif
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else {
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if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
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dophn_exec(class, swap,
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fd,
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getu32(swap, elfhdr.e_phoff),
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getu16(swap, elfhdr.e_phnum),
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getu16(swap, elfhdr.e_phentsize));
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}
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doshn(class, swap,
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fd,
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getu32(swap, elfhdr.e_shoff),
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getu16(swap, elfhdr.e_shnum),
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getu16(swap, elfhdr.e_shentsize));
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}
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return;
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}
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if (class == ELFCLASS64) {
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Elf64_Ehdr elfhdr;
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if (nbytes <= sizeof (Elf64_Ehdr))
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return;
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u.l = 1;
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(void) memcpy(&elfhdr, buf, sizeof elfhdr);
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swap = (u.c[sizeof(long) - 1] + 1) != elfhdr.e_ident[5];
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if (getu16(swap, elfhdr.e_type) == ET_CORE)
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#ifdef ELFCORE
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dophn_core(class, swap,
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fd,
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#ifdef USE_ARRAY_FOR_64BIT_TYPES
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getu32(swap, elfhdr.e_phoff[1]),
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#else
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getu64(swap, elfhdr.e_phoff),
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#endif
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getu16(swap, elfhdr.e_phnum),
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getu16(swap, elfhdr.e_phentsize));
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#else
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;
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#endif
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else
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{
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if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
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dophn_exec(class, swap,
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fd,
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#ifdef USE_ARRAY_FOR_64BIT_TYPES
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getu32(swap, elfhdr.e_phoff[1]),
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#else
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getu64(swap, elfhdr.e_phoff),
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#endif
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getu16(swap, elfhdr.e_phnum),
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getu16(swap, elfhdr.e_phentsize));
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}
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doshn(class, swap,
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fd,
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#ifdef USE_ARRAY_FOR_64BIT_TYPES
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getu32(swap, elfhdr.e_shoff[1]),
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#else
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getu64(swap, elfhdr.e_shoff),
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#endif
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getu16(swap, elfhdr.e_shnum),
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getu16(swap, elfhdr.e_shentsize));
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}
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return;
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}
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}
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#endif
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