647 lines
16 KiB
C
647 lines
16 KiB
C
#include "file.h"
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#ifdef BUILTIN_ELF
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#include <string.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 "readelf.h"
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#ifndef lint
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FILE_RCSID("@(#)$Id: readelf.c,v 1.22 2002/07/03 18:26:38 christos Exp $")
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#endif
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#ifdef ELFCORE
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static void dophn_core(int, int, int, off_t, int, size_t);
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#endif
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static void dophn_exec(int, int, int, off_t, int, size_t);
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static void doshn(int, int, int, off_t, int, size_t);
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static uint16_t getu16(int, uint16_t);
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static uint32_t getu32(int, uint32_t);
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static uint64_t getu64(int, uint64_t);
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static uint16_t
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getu16(int swap, 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(int swap, 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(int swap, 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(int class, int swap, int fd, off_t off, int num, 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(int class, int swap, int fd, off_t off, int num, size_t size)
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{
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Elf32_Phdr ph32;
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Elf32_Nhdr *nh32 = NULL;
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Elf64_Phdr ph64;
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Elf64_Nhdr *nh64 = NULL;
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char *linking_style = "statically";
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char *shared_libraries = "";
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char nbuf[BUFSIZ];
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int bufsize;
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size_t offset, nameoffset;
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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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case PT_NOTE:
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/*
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* This is a PT_NOTE section; loop through all the notes
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* in the section.
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*/
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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",
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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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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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nameoffset = offset;
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offset += nh_namesz;
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offset = ((offset + 3)/4)*4;
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if (offset + nh_descsz >= bufsize)
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break;
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if (nh_namesz == 4 &&
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strcmp(&nbuf[nameoffset], "GNU") == 0 &&
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nh_type == NT_GNU_VERSION &&
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nh_descsz == 16) {
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uint32_t *desc =
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(uint32_t *)&nbuf[offset];
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printf(", for GNU/");
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switch (getu32(swap, desc[0])) {
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case GNU_OS_LINUX:
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printf("Linux");
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break;
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case GNU_OS_HURD:
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printf("Hurd");
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break;
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case GNU_OS_SOLARIS:
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printf("Solaris");
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break;
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default:
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printf("<unknown>");
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}
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printf(" %d.%d.%d",
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getu32(swap, desc[1]),
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getu32(swap, desc[2]),
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getu32(swap, desc[3]));
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}
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if (nh_namesz == 7 &&
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strcmp(&nbuf[nameoffset], "NetBSD") == 0 &&
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nh_type == NT_NETBSD_VERSION &&
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nh_descsz == 4) {
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printf(", for NetBSD");
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/*
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* Version number is stuck at 199905,
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* and hence is basically content-free.
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*/
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}
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if (nh_namesz == 8 &&
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strcmp(&nbuf[nameoffset], "FreeBSD") == 0 &&
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nh_type == NT_FREEBSD_VERSION &&
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nh_descsz == 4) {
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uint32_t desc = getu32(swap,
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*(uint32_t *)&nbuf[offset]);
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printf(", for FreeBSD");
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/*
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* Contents is __FreeBSD_version,
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* whose relation to OS versions is
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* defined by a huge table in the
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* Porters' Handbook. Happily, the
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* first three digits are the version
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* number, at least in versions of
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* FreeBSD that use this note.
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*/
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printf(" %d.%d", desc / 100000,
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desc / 10000 % 10);
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if (desc / 1000 % 10 > 0)
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printf(".%d",
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desc / 1000 % 10);
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}
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if (nh_namesz == 8 &&
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strcmp(&nbuf[nameoffset], "OpenBSD") == 0 &&
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nh_type == NT_OPENBSD_VERSION &&
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nh_descsz == 4) {
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printf(", for OpenBSD");
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/* Content of note is always 0 */
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}
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}
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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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8, /* FreeBSD */
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28, /* Linux 2.0.36 */
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32, /* Linux (I forget which kernel version) */
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84, /* SunOS 5.x */
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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" or
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* "FreeBSD"; if one is found, try looking in various places in its
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* contents for a 16-character string containing only printable
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* characters - if found, that string should be the name of the program
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* that dropped core. Note: right after that 16-character string is,
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* at least in SunOS 5.x (and possibly other SVR4-flavored systems) and
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* Linux, a longer string (80 characters, in 5.x, probably other
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* SVR4-flavored systems, and Linux) containing the start of the
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* command line for that program.
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*
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* The signal number probably appears in a section of type NT_PRSTATUS,
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* but that's also rather OS-dependent, in ways that are harder to
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* dissect with heuristics, so I'm not bothering with the signal number.
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* (I suppose the signal number could be of interest in situations where
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* you don't have the binary of the program that dropped core; if you
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* *do* have that binary, the debugger will probably tell you what
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* signal it was.)
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*/
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#define OS_STYLE_SVR4 0
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#define OS_STYLE_FREEBSD 1
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#define OS_STYLE_NETBSD 2
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static const char *os_style_names[] = {
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"SVR4",
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"FreeBSD",
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"NetBSD",
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};
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static void
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dophn_core(int class, int swap, int fd, off_t off, int num, size_t size)
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{
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Elf32_Phdr ph32;
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Elf32_Nhdr *nh32 = NULL;
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Elf64_Phdr ph64;
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Elf64_Nhdr *nh64 = NULL;
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size_t offset, nameoffset, 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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int os_style = -1;
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/*
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* Loop through all the program headers.
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*/
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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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/*
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* This is a PT_NOTE section; loop through all the notes
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* in the section.
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*/
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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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* Check whether this note has the name "CORE" or
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* "FreeBSD", or "NetBSD-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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nameoffset = offset;
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offset += nh_namesz;
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offset = ((offset + 3)/4)*4;
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/*
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* Sigh. The 2.0.36 kernel in Debian 2.1, at
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* least, doesn't correctly implement name
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* sections, in core dumps, as specified by
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* the "Program Linking" section of "UNIX(R) System
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* V Release 4 Programmer's Guide: ANSI C and
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* Programming Support Tools", because my copy
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* clearly says "The first 'namesz' bytes in 'name'
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* contain a *null-terminated* [emphasis mine]
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* character representation of the entry's owner
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* or originator", but the 2.0.36 kernel code
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* doesn't include the terminating null in the
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* name....
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*/
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if (os_style == -1) {
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if ((nh_namesz == 4 &&
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strncmp(&nbuf[nameoffset],
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"CORE", 4) == 0) ||
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(nh_namesz == 5 &&
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strcmp(&nbuf[nameoffset],
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"CORE") == 0)) {
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os_style = OS_STYLE_SVR4;
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} else
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if ((nh_namesz == 8 &&
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strcmp(&nbuf[nameoffset],
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"FreeBSD") == 0)) {
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os_style = OS_STYLE_FREEBSD;
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} else
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if ((nh_namesz >= 11 &&
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strncmp(&nbuf[nameoffset],
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"NetBSD-CORE", 11) == 0)) {
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os_style = OS_STYLE_NETBSD;
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} else
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continue;
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printf(", %s-style", os_style_names[os_style]);
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}
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if (os_style == OS_STYLE_NETBSD &&
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nh_type == NT_NETBSD_CORE_PROCINFO) {
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uint32_t signo;
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/*
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* Extract the program name. It is at
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* offset 0x7c, and is up to 32-bytes,
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* including the terminating NUL.
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*/
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printf(", from '%.31s'", &nbuf[offset + 0x7c]);
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/*
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* Extract the signal number. It is at
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* offset 0x08.
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*/
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memcpy(&signo, &nbuf[offset + 0x08],
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sizeof(signo));
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printf(" (signal %u)", getu32(swap, signo));
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} else
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if (os_style != OS_STYLE_NETBSD &&
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nh_type == NT_PRPSINFO) {
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/*
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* Extract the program name. We assume
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* it to be 16 characters (that's what it
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* is in SunOS 5.x and Linux).
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*
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* Unfortunately, it's at a different offset
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* in varous OSes, so try multiple offsets.
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* If the characters aren't all printable,
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* reject 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
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* the end of the buffer; if
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* we are, just give up.
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*/
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if (noffset >= bufsize)
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goto tryanother;
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/*
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* Make sure we're not past
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* the end of the contents;
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* if we are, this obviously
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* isn't 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') {
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/*
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* A '\0' at the
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* beginning is
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* obviously wrong.
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* Any other '\0'
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* means we're done.
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*/
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if (j == 0)
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goto tryanother;
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else
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break;
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} else {
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/*
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* A nonprintable
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* character is also
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* wrong.
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*/
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#define isquote(c) (strchr("'\"`", (c)) != NULL)
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if (!isprint(c) ||
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isquote(c))
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goto tryanother;
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}
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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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break;
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tryanother:
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;
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}
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break;
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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(int fd, unsigned char *buf, int nbytes)
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{
|
|
union {
|
|
int32_t l;
|
|
char c[sizeof (int32_t)];
|
|
} u;
|
|
int class;
|
|
int swap;
|
|
|
|
/*
|
|
* If we can't seek, it must be a pipe, socket or fifo.
|
|
*/
|
|
if((lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) && (errno == ESPIPE))
|
|
fd = pipe2file(fd, buf, nbytes);
|
|
|
|
/*
|
|
* ELF executables have multiple section headers in arbitrary
|
|
* file locations and thus file(1) cannot determine it from easily.
|
|
* Instead we traverse thru all section headers until a symbol table
|
|
* one is found or else the binary is stripped.
|
|
*/
|
|
if (buf[EI_MAG0] != ELFMAG0
|
|
|| (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
|
|
|| buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
|
|
return;
|
|
|
|
|
|
class = buf[4];
|
|
|
|
if (class == ELFCLASS32) {
|
|
Elf32_Ehdr elfhdr;
|
|
if (nbytes <= sizeof (Elf32_Ehdr))
|
|
return;
|
|
|
|
|
|
u.l = 1;
|
|
(void) memcpy(&elfhdr, buf, sizeof elfhdr);
|
|
swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
|
|
|
|
if (getu16(swap, elfhdr.e_type) == ET_CORE)
|
|
#ifdef ELFCORE
|
|
dophn_core(class, swap,
|
|
fd,
|
|
getu32(swap, elfhdr.e_phoff),
|
|
getu16(swap, elfhdr.e_phnum),
|
|
getu16(swap, elfhdr.e_phentsize));
|
|
#else
|
|
;
|
|
#endif
|
|
else {
|
|
if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
|
|
dophn_exec(class, swap,
|
|
fd,
|
|
getu32(swap, elfhdr.e_phoff),
|
|
getu16(swap, elfhdr.e_phnum),
|
|
getu16(swap, elfhdr.e_phentsize));
|
|
}
|
|
doshn(class, swap,
|
|
fd,
|
|
getu32(swap, elfhdr.e_shoff),
|
|
getu16(swap, elfhdr.e_shnum),
|
|
getu16(swap, elfhdr.e_shentsize));
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (class == ELFCLASS64) {
|
|
Elf64_Ehdr elfhdr;
|
|
if (nbytes <= sizeof (Elf64_Ehdr))
|
|
return;
|
|
|
|
|
|
u.l = 1;
|
|
(void) memcpy(&elfhdr, buf, sizeof elfhdr);
|
|
swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
|
|
|
|
if (getu16(swap, elfhdr.e_type) == ET_CORE)
|
|
#ifdef ELFCORE
|
|
dophn_core(class, swap,
|
|
fd,
|
|
#ifdef USE_ARRAY_FOR_64BIT_TYPES
|
|
getu32(swap, elfhdr.e_phoff[1]),
|
|
#else
|
|
getu64(swap, elfhdr.e_phoff),
|
|
#endif
|
|
getu16(swap, elfhdr.e_phnum),
|
|
getu16(swap, elfhdr.e_phentsize));
|
|
#else
|
|
;
|
|
#endif
|
|
else
|
|
{
|
|
if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
|
|
dophn_exec(class, swap,
|
|
fd,
|
|
#ifdef USE_ARRAY_FOR_64BIT_TYPES
|
|
getu32(swap, elfhdr.e_phoff[1]),
|
|
#else
|
|
getu64(swap, elfhdr.e_phoff),
|
|
#endif
|
|
getu16(swap, elfhdr.e_phnum),
|
|
getu16(swap, elfhdr.e_phentsize));
|
|
}
|
|
doshn(class, swap,
|
|
fd,
|
|
#ifdef USE_ARRAY_FOR_64BIT_TYPES
|
|
getu32(swap, elfhdr.e_shoff[1]),
|
|
#else
|
|
getu64(swap, elfhdr.e_shoff),
|
|
#endif
|
|
getu16(swap, elfhdr.e_shnum),
|
|
getu16(swap, elfhdr.e_shentsize));
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
#endif
|