mirror of
https://github.com/autc04/Retro68.git
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940 lines
26 KiB
C
940 lines
26 KiB
C
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/* Sniff out modules from ELF headers visible in memory segments.
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Copyright (C) 2008-2012, 2014, 2015 Red Hat, Inc.
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This file is part of elfutils.
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This file is free software; you can redistribute it and/or modify
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it under the terms of either
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at
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your option) any later version
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at
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your option) any later version
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or both in parallel, as here.
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elfutils is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see <http://www.gnu.org/licenses/>. */
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#include <config.h>
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#include "../libelf/libelfP.h" /* For NOTE_ALIGN. */
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#undef _
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#include "libdwflP.h"
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#include "common.h"
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#include <elf.h>
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#include <gelf.h>
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#include <inttypes.h>
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#include <endian.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <system.h>
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/* A good size for the initial read from memory, if it's not too costly.
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This more than covers the phdrs and note segment in the average 64-bit
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binary. */
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#define INITIAL_READ 1024
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#if __BYTE_ORDER == __LITTLE_ENDIAN
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# define MY_ELFDATA ELFDATA2LSB
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#else
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# define MY_ELFDATA ELFDATA2MSB
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#endif
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/* Return user segment index closest to ADDR but not above it.
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If NEXT, return the closest to ADDR but not below it. */
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static int
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addr_segndx (Dwfl *dwfl, size_t segment, GElf_Addr addr, bool next)
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{
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int ndx = -1;
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do
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{
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if (dwfl->lookup_segndx[segment] >= 0)
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ndx = dwfl->lookup_segndx[segment];
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if (++segment >= dwfl->lookup_elts - 1)
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return next ? ndx + 1 : ndx;
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}
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while (dwfl->lookup_addr[segment] < addr);
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if (next)
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{
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while (dwfl->lookup_segndx[segment] < 0)
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if (++segment >= dwfl->lookup_elts - 1)
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return ndx + 1;
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ndx = dwfl->lookup_segndx[segment];
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}
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return ndx;
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}
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/* Return whether there is SZ bytes available at PTR till END. */
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static bool
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buf_has_data (const void *ptr, const void *end, size_t sz)
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{
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return ptr < end && (size_t) (end - ptr) >= sz;
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}
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/* Read SZ bytes into *RETP from *PTRP (limited by END) in format EI_DATA.
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Function comes from src/readelf.c . */
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static bool
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buf_read_ulong (unsigned char ei_data, size_t sz,
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const void **ptrp, const void *end, uint64_t *retp)
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{
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if (! buf_has_data (*ptrp, end, sz))
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return false;
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union
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{
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uint64_t u64;
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uint32_t u32;
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} u;
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memcpy (&u, *ptrp, sz);
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(*ptrp) += sz;
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if (retp == NULL)
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return true;
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if (MY_ELFDATA != ei_data)
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{
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if (sz == 4)
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CONVERT (u.u32);
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else
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CONVERT (u.u64);
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}
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if (sz == 4)
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*retp = u.u32;
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else
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*retp = u.u64;
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return true;
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}
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/* Try to find matching entry for module from address MODULE_START to
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MODULE_END in NT_FILE note located at NOTE_FILE of NOTE_FILE_SIZE
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bytes in format EI_CLASS and EI_DATA. */
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static const char *
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handle_file_note (GElf_Addr module_start, GElf_Addr module_end,
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unsigned char ei_class, unsigned char ei_data,
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const void *note_file, size_t note_file_size)
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{
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if (note_file == NULL)
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return NULL;
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size_t sz;
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switch (ei_class)
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{
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case ELFCLASS32:
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sz = 4;
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break;
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case ELFCLASS64:
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sz = 8;
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break;
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default:
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return NULL;
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}
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const void *ptr = note_file;
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const void *end = note_file + note_file_size;
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uint64_t count;
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if (! buf_read_ulong (ei_data, sz, &ptr, end, &count))
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return NULL;
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if (! buf_read_ulong (ei_data, sz, &ptr, end, NULL)) // page_size
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return NULL;
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uint64_t maxcount = (size_t) (end - ptr) / (3 * sz);
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if (count > maxcount)
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return NULL;
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/* Where file names are stored. */
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const char *fptr = ptr + 3 * count * sz;
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ssize_t firstix = -1;
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ssize_t lastix = -1;
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for (size_t mix = 0; mix < count; mix++)
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{
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uint64_t mstart, mend, moffset;
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if (! buf_read_ulong (ei_data, sz, &ptr, fptr, &mstart)
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|| ! buf_read_ulong (ei_data, sz, &ptr, fptr, &mend)
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|| ! buf_read_ulong (ei_data, sz, &ptr, fptr, &moffset))
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return NULL;
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if (mstart == module_start && moffset == 0)
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firstix = lastix = mix;
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if (firstix != -1 && mstart < module_end)
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lastix = mix;
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if (mend >= module_end)
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break;
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}
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if (firstix == -1)
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return NULL;
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const char *retval = NULL;
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for (ssize_t mix = 0; mix <= lastix; mix++)
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{
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const char *fnext = memchr (fptr, 0, (const char *) end - fptr);
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if (fnext == NULL)
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return NULL;
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if (mix == firstix)
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retval = fptr;
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if (firstix < mix && mix <= lastix && strcmp (fptr, retval) != 0)
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return NULL;
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fptr = fnext + 1;
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}
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return retval;
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}
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/* Return true iff we are certain ELF cannot match BUILD_ID of
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BUILD_ID_LEN bytes. Pass DISK_FILE_HAS_BUILD_ID as false if it is
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certain ELF does not contain build-id (it is only a performance hit
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to pass it always as true). */
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static bool
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invalid_elf (Elf *elf, bool disk_file_has_build_id,
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const void *build_id, size_t build_id_len)
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{
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if (! disk_file_has_build_id && build_id_len > 0)
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{
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/* Module found in segments with build-id is more reliable
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than a module found via DT_DEBUG on disk without any
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build-id. */
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return true;
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}
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if (disk_file_has_build_id && build_id_len > 0)
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{
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const void *elf_build_id;
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ssize_t elf_build_id_len;
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/* If there is a build id in the elf file, check it. */
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elf_build_id_len = INTUSE(dwelf_elf_gnu_build_id) (elf, &elf_build_id);
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if (elf_build_id_len > 0)
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{
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if (build_id_len != (size_t) elf_build_id_len
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|| memcmp (build_id, elf_build_id, build_id_len) != 0)
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return true;
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}
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}
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return false;
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}
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int
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dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
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Dwfl_Memory_Callback *memory_callback,
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void *memory_callback_arg,
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Dwfl_Module_Callback *read_eagerly,
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void *read_eagerly_arg,
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const void *note_file, size_t note_file_size,
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const struct r_debug_info *r_debug_info)
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{
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size_t segment = ndx;
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if (segment >= dwfl->lookup_elts)
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segment = dwfl->lookup_elts - 1;
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while (segment > 0
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&& (dwfl->lookup_segndx[segment] > ndx
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|| dwfl->lookup_segndx[segment] == -1))
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--segment;
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while (dwfl->lookup_segndx[segment] < ndx)
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if (++segment == dwfl->lookup_elts)
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return 0;
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GElf_Addr start = dwfl->lookup_addr[segment];
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inline bool segment_read (int segndx,
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void **buffer, size_t *buffer_available,
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GElf_Addr addr, size_t minread)
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{
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return ! (*memory_callback) (dwfl, segndx, buffer, buffer_available,
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addr, minread, memory_callback_arg);
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}
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inline void release_buffer (void **buffer, size_t *buffer_available)
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{
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if (*buffer != NULL)
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(void) segment_read (-1, buffer, buffer_available, 0, 0);
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}
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/* First read in the file header and check its sanity. */
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void *buffer = NULL;
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size_t buffer_available = INITIAL_READ;
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Elf *elf = NULL;
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int fd = -1;
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/* We might have to reserve some memory for the phdrs. Set to NULL
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here so we can always safely free it. */
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void *phdrsp = NULL;
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inline int finish (void)
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{
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free (phdrsp);
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release_buffer (&buffer, &buffer_available);
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if (elf != NULL)
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elf_end (elf);
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if (fd != -1)
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close (fd);
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return ndx;
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}
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if (segment_read (ndx, &buffer, &buffer_available,
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start, sizeof (Elf64_Ehdr))
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|| memcmp (buffer, ELFMAG, SELFMAG) != 0)
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return finish ();
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inline bool read_portion (void **data, size_t *data_size,
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GElf_Addr vaddr, size_t filesz)
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{
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if (vaddr - start + filesz > buffer_available
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/* If we're in string mode, then don't consider the buffer we have
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sufficient unless it contains the terminator of the string. */
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|| (filesz == 0 && memchr (vaddr - start + buffer, '\0',
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buffer_available - (vaddr - start)) == NULL))
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{
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*data = NULL;
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*data_size = filesz;
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return segment_read (addr_segndx (dwfl, segment, vaddr, false),
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data, data_size, vaddr, filesz);
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}
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/* We already have this whole note segment from our initial read. */
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*data = vaddr - start + buffer;
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*data_size = 0;
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return false;
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}
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inline void finish_portion (void **data, size_t *data_size)
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{
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if (*data_size != 0)
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release_buffer (data, data_size);
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}
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/* Extract the information we need from the file header. */
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const unsigned char *e_ident;
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unsigned char ei_class;
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unsigned char ei_data;
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uint16_t e_type;
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union
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{
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Elf32_Ehdr e32;
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Elf64_Ehdr e64;
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} ehdr;
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GElf_Off phoff;
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uint_fast16_t phnum;
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uint_fast16_t phentsize;
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GElf_Off shdrs_end;
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Elf_Data xlatefrom =
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{
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.d_type = ELF_T_EHDR,
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.d_buf = (void *) buffer,
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.d_version = EV_CURRENT,
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};
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Elf_Data xlateto =
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{
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.d_type = ELF_T_EHDR,
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.d_buf = &ehdr,
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.d_size = sizeof ehdr,
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.d_version = EV_CURRENT,
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};
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e_ident = ((const unsigned char *) buffer);
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ei_class = e_ident[EI_CLASS];
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ei_data = e_ident[EI_DATA];
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switch (ei_class)
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{
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case ELFCLASS32:
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xlatefrom.d_size = sizeof (Elf32_Ehdr);
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if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
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return finish ();
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e_type = ehdr.e32.e_type;
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phoff = ehdr.e32.e_phoff;
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phnum = ehdr.e32.e_phnum;
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phentsize = ehdr.e32.e_phentsize;
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if (phentsize != sizeof (Elf32_Phdr))
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return finish ();
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shdrs_end = ehdr.e32.e_shoff + ehdr.e32.e_shnum * ehdr.e32.e_shentsize;
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break;
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case ELFCLASS64:
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xlatefrom.d_size = sizeof (Elf64_Ehdr);
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if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
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return finish ();
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e_type = ehdr.e64.e_type;
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phoff = ehdr.e64.e_phoff;
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phnum = ehdr.e64.e_phnum;
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phentsize = ehdr.e64.e_phentsize;
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if (phentsize != sizeof (Elf64_Phdr))
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return finish ();
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shdrs_end = ehdr.e64.e_shoff + ehdr.e64.e_shnum * ehdr.e64.e_shentsize;
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break;
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default:
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return finish ();
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}
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/* The file header tells where to find the program headers.
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These are what we need to find the boundaries of the module.
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Without them, we don't have a module to report. */
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if (phnum == 0)
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return finish ();
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xlatefrom.d_type = xlateto.d_type = ELF_T_PHDR;
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xlatefrom.d_size = phnum * phentsize;
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void *ph_buffer = NULL;
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size_t ph_buffer_size = 0;
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if (read_portion (&ph_buffer, &ph_buffer_size,
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start + phoff, xlatefrom.d_size))
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return finish ();
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xlatefrom.d_buf = ph_buffer;
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bool class32 = ei_class == ELFCLASS32;
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size_t phdr_size = class32 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr);
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if (unlikely (phnum > SIZE_MAX / phdr_size))
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return finish ();
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const size_t phdrsp_bytes = phnum * phdr_size;
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phdrsp = malloc (phdrsp_bytes);
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if (unlikely (phdrsp == NULL))
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return finish ();
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xlateto.d_buf = phdrsp;
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xlateto.d_size = phdrsp_bytes;
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/* Track the bounds of the file visible in memory. */
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GElf_Off file_trimmed_end = 0; /* Proper p_vaddr + p_filesz end. */
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GElf_Off file_end = 0; /* Rounded up to effective page size. */
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GElf_Off contiguous = 0; /* Visible as contiguous file from START. */
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GElf_Off total_filesz = 0; /* Total size of data to read. */
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/* Collect the bias between START and the containing PT_LOAD's p_vaddr. */
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GElf_Addr bias = 0;
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bool found_bias = false;
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||
|
/* Collect the unbiased bounds of the module here. */
|
||
|
GElf_Addr module_start = -1l;
|
||
|
GElf_Addr module_end = 0;
|
||
|
GElf_Addr module_address_sync = 0;
|
||
|
|
||
|
/* If we see PT_DYNAMIC, record it here. */
|
||
|
GElf_Addr dyn_vaddr = 0;
|
||
|
GElf_Xword dyn_filesz = 0;
|
||
|
|
||
|
/* Collect the build ID bits here. */
|
||
|
void *build_id = NULL;
|
||
|
size_t build_id_len = 0;
|
||
|
GElf_Addr build_id_vaddr = 0;
|
||
|
|
||
|
/* Consider a PT_NOTE we've found in the image. */
|
||
|
inline void consider_notes (GElf_Addr vaddr, GElf_Xword filesz)
|
||
|
{
|
||
|
/* If we have already seen a build ID, we don't care any more. */
|
||
|
if (build_id != NULL || filesz == 0)
|
||
|
return;
|
||
|
|
||
|
void *data;
|
||
|
size_t data_size;
|
||
|
if (read_portion (&data, &data_size, vaddr, filesz))
|
||
|
return;
|
||
|
|
||
|
assert (sizeof (Elf32_Nhdr) == sizeof (Elf64_Nhdr));
|
||
|
|
||
|
void *notes;
|
||
|
if (ei_data == MY_ELFDATA)
|
||
|
notes = data;
|
||
|
else
|
||
|
{
|
||
|
notes = malloc (filesz);
|
||
|
if (unlikely (notes == NULL))
|
||
|
return;
|
||
|
xlatefrom.d_type = xlateto.d_type = ELF_T_NHDR;
|
||
|
xlatefrom.d_buf = (void *) data;
|
||
|
xlatefrom.d_size = filesz;
|
||
|
xlateto.d_buf = notes;
|
||
|
xlateto.d_size = filesz;
|
||
|
if (elf32_xlatetom (&xlateto, &xlatefrom,
|
||
|
ehdr.e32.e_ident[EI_DATA]) == NULL)
|
||
|
goto done;
|
||
|
}
|
||
|
|
||
|
const GElf_Nhdr *nh = notes;
|
||
|
while ((const void *) nh < (const void *) notes + filesz)
|
||
|
{
|
||
|
const void *note_name = nh + 1;
|
||
|
const void *note_desc = note_name + NOTE_ALIGN (nh->n_namesz);
|
||
|
if (unlikely ((size_t) ((const void *) notes + filesz
|
||
|
- note_desc) < nh->n_descsz))
|
||
|
break;
|
||
|
|
||
|
if (nh->n_type == NT_GNU_BUILD_ID
|
||
|
&& nh->n_descsz > 0
|
||
|
&& nh->n_namesz == sizeof "GNU"
|
||
|
&& !memcmp (note_name, "GNU", sizeof "GNU"))
|
||
|
{
|
||
|
build_id_vaddr = note_desc - (const void *) notes + vaddr;
|
||
|
build_id_len = nh->n_descsz;
|
||
|
build_id = malloc (nh->n_descsz);
|
||
|
if (likely (build_id != NULL))
|
||
|
memcpy (build_id, note_desc, build_id_len);
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
nh = note_desc + NOTE_ALIGN (nh->n_descsz);
|
||
|
}
|
||
|
|
||
|
done:
|
||
|
if (notes != data)
|
||
|
free (notes);
|
||
|
finish_portion (&data, &data_size);
|
||
|
}
|
||
|
|
||
|
/* Consider each of the program headers we've read from the image. */
|
||
|
inline void consider_phdr (GElf_Word type,
|
||
|
GElf_Addr vaddr, GElf_Xword memsz,
|
||
|
GElf_Off offset, GElf_Xword filesz,
|
||
|
GElf_Xword align)
|
||
|
{
|
||
|
switch (type)
|
||
|
{
|
||
|
case PT_DYNAMIC:
|
||
|
dyn_vaddr = vaddr;
|
||
|
dyn_filesz = filesz;
|
||
|
break;
|
||
|
|
||
|
case PT_NOTE:
|
||
|
/* We calculate from the p_offset of the note segment,
|
||
|
because we don't yet know the bias for its p_vaddr. */
|
||
|
consider_notes (start + offset, filesz);
|
||
|
break;
|
||
|
|
||
|
case PT_LOAD:
|
||
|
align = dwfl->segment_align > 1 ? dwfl->segment_align : align ?: 1;
|
||
|
|
||
|
GElf_Addr vaddr_end = (vaddr + memsz + align - 1) & -align;
|
||
|
GElf_Addr filesz_vaddr = filesz < memsz ? vaddr + filesz : vaddr_end;
|
||
|
GElf_Off filesz_offset = filesz_vaddr - vaddr + offset;
|
||
|
|
||
|
if (file_trimmed_end < offset + filesz)
|
||
|
{
|
||
|
file_trimmed_end = offset + filesz;
|
||
|
|
||
|
/* Trim the last segment so we don't bother with zeros
|
||
|
in the last page that are off the end of the file.
|
||
|
However, if the extra bit in that page includes the
|
||
|
section headers, keep them. */
|
||
|
if (shdrs_end <= filesz_offset && shdrs_end > file_trimmed_end)
|
||
|
{
|
||
|
filesz += shdrs_end - file_trimmed_end;
|
||
|
file_trimmed_end = shdrs_end;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
total_filesz += filesz;
|
||
|
|
||
|
if (file_end < filesz_offset)
|
||
|
{
|
||
|
file_end = filesz_offset;
|
||
|
if (filesz_vaddr - start == filesz_offset)
|
||
|
contiguous = file_end;
|
||
|
}
|
||
|
|
||
|
if (!found_bias && (offset & -align) == 0
|
||
|
&& likely (filesz_offset >= phoff + phnum * phentsize))
|
||
|
{
|
||
|
bias = start - vaddr;
|
||
|
found_bias = true;
|
||
|
}
|
||
|
|
||
|
if ((vaddr & -align) < module_start)
|
||
|
{
|
||
|
module_start = vaddr & -align;
|
||
|
module_address_sync = vaddr + memsz;
|
||
|
}
|
||
|
|
||
|
if (module_end < vaddr_end)
|
||
|
module_end = vaddr_end;
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
Elf32_Phdr (*p32)[phnum] = phdrsp;
|
||
|
Elf64_Phdr (*p64)[phnum] = phdrsp;
|
||
|
if (ei_class == ELFCLASS32)
|
||
|
{
|
||
|
if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
|
||
|
found_bias = false; /* Trigger error check. */
|
||
|
else
|
||
|
for (uint_fast16_t i = 0; i < phnum; ++i)
|
||
|
consider_phdr ((*p32)[i].p_type,
|
||
|
(*p32)[i].p_vaddr, (*p32)[i].p_memsz,
|
||
|
(*p32)[i].p_offset, (*p32)[i].p_filesz,
|
||
|
(*p32)[i].p_align);
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
|
||
|
found_bias = false; /* Trigger error check. */
|
||
|
else
|
||
|
for (uint_fast16_t i = 0; i < phnum; ++i)
|
||
|
consider_phdr ((*p64)[i].p_type,
|
||
|
(*p64)[i].p_vaddr, (*p64)[i].p_memsz,
|
||
|
(*p64)[i].p_offset, (*p64)[i].p_filesz,
|
||
|
(*p64)[i].p_align);
|
||
|
}
|
||
|
|
||
|
finish_portion (&ph_buffer, &ph_buffer_size);
|
||
|
|
||
|
/* We must have seen the segment covering offset 0, or else the ELF
|
||
|
header we read at START was not produced by these program headers. */
|
||
|
if (unlikely (!found_bias))
|
||
|
{
|
||
|
free (build_id);
|
||
|
return finish ();
|
||
|
}
|
||
|
|
||
|
/* Now we know enough to report a module for sure: its bounds. */
|
||
|
module_start += bias;
|
||
|
module_end += bias;
|
||
|
|
||
|
dyn_vaddr += bias;
|
||
|
|
||
|
/* NAME found from link map has precedence over DT_SONAME possibly read
|
||
|
below. */
|
||
|
bool name_is_final = false;
|
||
|
|
||
|
/* Try to match up DYN_VADDR against L_LD as found in link map.
|
||
|
Segments sniffing may guess invalid address as the first read-only memory
|
||
|
mapping may not be dumped to the core file (if ELF headers are not dumped)
|
||
|
and the ELF header is dumped first with the read/write mapping of the same
|
||
|
file at higher addresses. */
|
||
|
if (r_debug_info != NULL)
|
||
|
for (const struct r_debug_info_module *module = r_debug_info->module;
|
||
|
module != NULL; module = module->next)
|
||
|
if (module_start <= module->l_ld && module->l_ld < module_end)
|
||
|
{
|
||
|
/* L_LD read from link map must be right while DYN_VADDR is unsafe.
|
||
|
Therefore subtract DYN_VADDR and add L_LD to get a possibly
|
||
|
corrective displacement for all addresses computed so far. */
|
||
|
GElf_Addr fixup = module->l_ld - dyn_vaddr;
|
||
|
if ((fixup & (dwfl->segment_align - 1)) == 0
|
||
|
&& module_start + fixup <= module->l_ld
|
||
|
&& module->l_ld < module_end + fixup)
|
||
|
{
|
||
|
module_start += fixup;
|
||
|
module_end += fixup;
|
||
|
dyn_vaddr += fixup;
|
||
|
bias += fixup;
|
||
|
if (module->name[0] != '\0')
|
||
|
{
|
||
|
name = basename (module->name);
|
||
|
name_is_final = true;
|
||
|
}
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if (r_debug_info != NULL)
|
||
|
{
|
||
|
bool skip_this_module = false;
|
||
|
for (struct r_debug_info_module *module = r_debug_info->module;
|
||
|
module != NULL; module = module->next)
|
||
|
if ((module_end > module->start && module_start < module->end)
|
||
|
|| dyn_vaddr == module->l_ld)
|
||
|
{
|
||
|
if (module->elf != NULL
|
||
|
&& invalid_elf (module->elf, module->disk_file_has_build_id,
|
||
|
build_id, build_id_len))
|
||
|
{
|
||
|
elf_end (module->elf);
|
||
|
close (module->fd);
|
||
|
module->elf = NULL;
|
||
|
module->fd = -1;
|
||
|
}
|
||
|
if (module->elf != NULL)
|
||
|
{
|
||
|
/* Ignore this found module if it would conflict in address
|
||
|
space with any already existing module of DWFL. */
|
||
|
skip_this_module = true;
|
||
|
}
|
||
|
}
|
||
|
if (skip_this_module)
|
||
|
{
|
||
|
free (build_id);
|
||
|
return finish ();
|
||
|
}
|
||
|
}
|
||
|
|
||
|
const char *file_note_name = handle_file_note (module_start, module_end,
|
||
|
ei_class, ei_data,
|
||
|
note_file, note_file_size);
|
||
|
if (file_note_name)
|
||
|
{
|
||
|
name = file_note_name;
|
||
|
name_is_final = true;
|
||
|
bool invalid = false;
|
||
|
fd = open (name, O_RDONLY);
|
||
|
if (fd >= 0)
|
||
|
{
|
||
|
Dwfl_Error error = __libdw_open_file (&fd, &elf, true, false);
|
||
|
if (error == DWFL_E_NOERROR)
|
||
|
invalid = invalid_elf (elf, true /* disk_file_has_build_id */,
|
||
|
build_id, build_id_len);
|
||
|
}
|
||
|
if (invalid)
|
||
|
{
|
||
|
/* The file was there, but the build_id didn't match. We
|
||
|
still want to report the module, but need to get the ELF
|
||
|
some other way if possible. */
|
||
|
close (fd);
|
||
|
fd = -1;
|
||
|
elf_end (elf);
|
||
|
elf = NULL;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* Our return value now says to skip the segments contained
|
||
|
within the module. */
|
||
|
ndx = addr_segndx (dwfl, segment, module_end, true);
|
||
|
|
||
|
/* Examine its .dynamic section to get more interesting details.
|
||
|
If it has DT_SONAME, we'll use that as the module name.
|
||
|
If it has a DT_DEBUG, then it's actually a PIE rather than a DSO.
|
||
|
We need its DT_STRTAB and DT_STRSZ to decipher DT_SONAME,
|
||
|
and they also tell us the essential portion of the file
|
||
|
for fetching symbols. */
|
||
|
GElf_Addr soname_stroff = 0;
|
||
|
GElf_Addr dynstr_vaddr = 0;
|
||
|
GElf_Xword dynstrsz = 0;
|
||
|
bool execlike = false;
|
||
|
inline bool consider_dyn (GElf_Sxword tag, GElf_Xword val)
|
||
|
{
|
||
|
switch (tag)
|
||
|
{
|
||
|
default:
|
||
|
return false;
|
||
|
|
||
|
case DT_DEBUG:
|
||
|
execlike = true;
|
||
|
break;
|
||
|
|
||
|
case DT_SONAME:
|
||
|
soname_stroff = val;
|
||
|
break;
|
||
|
|
||
|
case DT_STRTAB:
|
||
|
dynstr_vaddr = val;
|
||
|
break;
|
||
|
|
||
|
case DT_STRSZ:
|
||
|
dynstrsz = val;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
return soname_stroff != 0 && dynstr_vaddr != 0 && dynstrsz != 0;
|
||
|
}
|
||
|
|
||
|
const size_t dyn_entsize = (ei_class == ELFCLASS32
|
||
|
? sizeof (Elf32_Dyn) : sizeof (Elf64_Dyn));
|
||
|
void *dyn_data = NULL;
|
||
|
size_t dyn_data_size = 0;
|
||
|
if (dyn_filesz != 0 && dyn_filesz % dyn_entsize == 0
|
||
|
&& ! read_portion (&dyn_data, &dyn_data_size, dyn_vaddr, dyn_filesz))
|
||
|
{
|
||
|
void *dyns = malloc (dyn_filesz);
|
||
|
Elf32_Dyn (*d32)[dyn_filesz / sizeof (Elf32_Dyn)] = dyns;
|
||
|
Elf64_Dyn (*d64)[dyn_filesz / sizeof (Elf64_Dyn)] = dyns;
|
||
|
if (unlikely (dyns == NULL))
|
||
|
return finish ();
|
||
|
|
||
|
xlatefrom.d_type = xlateto.d_type = ELF_T_DYN;
|
||
|
xlatefrom.d_buf = (void *) dyn_data;
|
||
|
xlatefrom.d_size = dyn_filesz;
|
||
|
xlateto.d_buf = dyns;
|
||
|
xlateto.d_size = dyn_filesz;
|
||
|
|
||
|
if (ei_class == ELFCLASS32)
|
||
|
{
|
||
|
if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
|
||
|
for (size_t i = 0; i < dyn_filesz / sizeof (Elf32_Dyn); ++i)
|
||
|
if (consider_dyn ((*d32)[i].d_tag, (*d32)[i].d_un.d_val))
|
||
|
break;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
|
||
|
for (size_t i = 0; i < dyn_filesz / sizeof (Elf64_Dyn); ++i)
|
||
|
if (consider_dyn ((*d64)[i].d_tag, (*d64)[i].d_un.d_val))
|
||
|
break;
|
||
|
}
|
||
|
free (dyns);
|
||
|
}
|
||
|
finish_portion (&dyn_data, &dyn_data_size);
|
||
|
|
||
|
/* We'll use the name passed in or a stupid default if not DT_SONAME. */
|
||
|
if (name == NULL)
|
||
|
name = e_type == ET_EXEC ? "[exe]" : execlike ? "[pie]" : "[dso]";
|
||
|
|
||
|
void *soname = NULL;
|
||
|
size_t soname_size = 0;
|
||
|
if (! name_is_final && dynstrsz != 0 && dynstr_vaddr != 0)
|
||
|
{
|
||
|
/* We know the bounds of the .dynstr section.
|
||
|
|
||
|
The DYNSTR_VADDR pointer comes from the .dynamic section
|
||
|
(DT_STRTAB, detected above). Ordinarily the dynamic linker
|
||
|
will have adjusted this pointer in place so it's now an
|
||
|
absolute address. But sometimes .dynamic is read-only (in
|
||
|
vDSOs and odd architectures), and sometimes the adjustment
|
||
|
just hasn't happened yet in the memory image we looked at.
|
||
|
So treat DYNSTR_VADDR as an absolute address if it falls
|
||
|
within the module bounds, or try applying the phdr bias
|
||
|
when that adjusts it to fall within the module bounds. */
|
||
|
|
||
|
if ((dynstr_vaddr < module_start || dynstr_vaddr >= module_end)
|
||
|
&& dynstr_vaddr + bias >= module_start
|
||
|
&& dynstr_vaddr + bias < module_end)
|
||
|
dynstr_vaddr += bias;
|
||
|
|
||
|
if (unlikely (dynstr_vaddr + dynstrsz > module_end))
|
||
|
dynstrsz = 0;
|
||
|
|
||
|
/* Try to get the DT_SONAME string. */
|
||
|
if (soname_stroff != 0 && soname_stroff + 1 < dynstrsz
|
||
|
&& ! read_portion (&soname, &soname_size,
|
||
|
dynstr_vaddr + soname_stroff, 0))
|
||
|
name = soname;
|
||
|
}
|
||
|
|
||
|
/* Now that we have chosen the module's name and bounds, report it.
|
||
|
If we found a build ID, report that too. */
|
||
|
|
||
|
Dwfl_Module *mod = INTUSE(dwfl_report_module) (dwfl, name,
|
||
|
module_start, module_end);
|
||
|
|
||
|
// !execlike && ET_EXEC is PIE.
|
||
|
// execlike && !ET_EXEC is a static executable.
|
||
|
if (mod != NULL && (execlike || ehdr.e32.e_type == ET_EXEC))
|
||
|
mod->is_executable = true;
|
||
|
|
||
|
if (likely (mod != NULL) && build_id != NULL
|
||
|
&& unlikely (INTUSE(dwfl_module_report_build_id) (mod,
|
||
|
build_id,
|
||
|
build_id_len,
|
||
|
build_id_vaddr)))
|
||
|
{
|
||
|
mod->gc = true;
|
||
|
mod = NULL;
|
||
|
}
|
||
|
|
||
|
/* At this point we do not need BUILD_ID or NAME any more.
|
||
|
They have been copied. */
|
||
|
free (build_id);
|
||
|
finish_portion (&soname, &soname_size);
|
||
|
|
||
|
if (unlikely (mod == NULL))
|
||
|
{
|
||
|
ndx = -1;
|
||
|
return finish ();
|
||
|
}
|
||
|
|
||
|
/* We have reported the module. Now let the caller decide whether we
|
||
|
should read the whole thing in right now. */
|
||
|
|
||
|
const GElf_Off cost = (contiguous < file_trimmed_end ? total_filesz
|
||
|
: buffer_available >= contiguous ? 0
|
||
|
: contiguous - buffer_available);
|
||
|
const GElf_Off worthwhile = ((dynstr_vaddr == 0 || dynstrsz == 0) ? 0
|
||
|
: dynstr_vaddr + dynstrsz - start);
|
||
|
const GElf_Off whole = MAX (file_trimmed_end, shdrs_end);
|
||
|
|
||
|
if (elf == NULL
|
||
|
&& (*read_eagerly) (MODCB_ARGS (mod), &buffer, &buffer_available,
|
||
|
cost, worthwhile, whole, contiguous,
|
||
|
read_eagerly_arg, &elf)
|
||
|
&& elf == NULL)
|
||
|
{
|
||
|
/* The caller wants to read the whole file in right now, but hasn't
|
||
|
done it for us. Fill in a local image of the virtual file. */
|
||
|
|
||
|
void *contents = calloc (1, file_trimmed_end);
|
||
|
if (unlikely (contents == NULL))
|
||
|
return finish ();
|
||
|
|
||
|
inline void final_read (size_t offset, GElf_Addr vaddr, size_t size)
|
||
|
{
|
||
|
void *into = contents + offset;
|
||
|
size_t read_size = size;
|
||
|
(void) segment_read (addr_segndx (dwfl, segment, vaddr, false),
|
||
|
&into, &read_size, vaddr, size);
|
||
|
}
|
||
|
|
||
|
if (contiguous < file_trimmed_end)
|
||
|
{
|
||
|
/* We can't use the memory image verbatim as the file image.
|
||
|
So we'll be reading into a local image of the virtual file. */
|
||
|
|
||
|
inline void read_phdr (GElf_Word type, GElf_Addr vaddr,
|
||
|
GElf_Off offset, GElf_Xword filesz)
|
||
|
{
|
||
|
if (type == PT_LOAD)
|
||
|
final_read (offset, vaddr + bias, filesz);
|
||
|
}
|
||
|
|
||
|
if (ei_class == ELFCLASS32)
|
||
|
for (uint_fast16_t i = 0; i < phnum; ++i)
|
||
|
read_phdr ((*p32)[i].p_type, (*p32)[i].p_vaddr,
|
||
|
(*p32)[i].p_offset, (*p32)[i].p_filesz);
|
||
|
else
|
||
|
for (uint_fast16_t i = 0; i < phnum; ++i)
|
||
|
read_phdr ((*p64)[i].p_type, (*p64)[i].p_vaddr,
|
||
|
(*p64)[i].p_offset, (*p64)[i].p_filesz);
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
/* The whole file sits contiguous in memory,
|
||
|
but the caller didn't want to just do it. */
|
||
|
|
||
|
const size_t have = MIN (buffer_available, file_trimmed_end);
|
||
|
memcpy (contents, buffer, have);
|
||
|
|
||
|
if (have < file_trimmed_end)
|
||
|
final_read (have, start + have, file_trimmed_end - have);
|
||
|
}
|
||
|
|
||
|
elf = elf_memory (contents, file_trimmed_end);
|
||
|
if (unlikely (elf == NULL))
|
||
|
free (contents);
|
||
|
else
|
||
|
elf->flags |= ELF_F_MALLOCED;
|
||
|
}
|
||
|
|
||
|
if (elf != NULL)
|
||
|
{
|
||
|
/* Install the file in the module. */
|
||
|
mod->main.elf = elf;
|
||
|
elf = NULL;
|
||
|
fd = -1;
|
||
|
mod->main.vaddr = module_start - bias;
|
||
|
mod->main.address_sync = module_address_sync;
|
||
|
mod->main_bias = bias;
|
||
|
}
|
||
|
|
||
|
return finish ();
|
||
|
}
|