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/* Find the split (or skeleton) unit for a given unit.
Copyright (C) 2018 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
it under the terms of either
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at
your option) any later version
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at
your option) any later version
or both in parallel, as here.
elfutils is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see <http://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "libdwP.h"
#include "libelfP.h"
#include "eu-search.h"
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
static void
try_split_file (Dwarf_CU *cu, const char *dwo_path)
{
int split_fd = open (dwo_path, O_RDONLY);
if (split_fd != -1)
{
Dwarf *split_dwarf = dwarf_begin (split_fd, DWARF_C_READ);
if (split_dwarf != NULL)
{
Dwarf_CU *split = NULL;
while (INTUSE(dwarf_get_units) (split_dwarf, split, &split,
NULL, NULL, NULL, NULL) == 0)
{
if (split->unit_type == DW_UT_split_compile
&& cu->unit_id8 == split->unit_id8)
{
if (eu_tsearch (split->dbg, &cu->dbg->split_tree,
__libdw_finddbg_cb) == NULL)
{
/* Something went wrong. Don't link. */
__libdw_seterrno (DWARF_E_NOMEM);
break;
}
/* Link skeleton and split compile units. */
__libdw_link_skel_split (cu, split);
/* We have everything we need from this ELF
file. And we are going to close the fd to
not run out of file descriptors. */
elf_cntl (split_dwarf->elf, ELF_C_FDDONE);
break;
}
}
if (cu->split == (Dwarf_CU *) -1)
dwarf_end (split_dwarf);
}
/* Always close, because we don't want to run out of file
descriptors. See also the elf_fcntl ELF_C_FDDONE call
above. */
close (split_fd);
}
}
static void
try_dwp_file (Dwarf_CU *cu)
{
if (cu->dbg->dwp_dwarf == NULL)
{
if (cu->dbg->elfpath != NULL)
{
/* The DWARF 5 standard says "the package file is typically placed in
the same directory as the application, and is given the same name
with a '.dwp' extension". */
size_t elfpath_len = strlen (cu->dbg->elfpath);
char *dwp_path = malloc (elfpath_len + 5);
if (dwp_path == NULL)
{
__libdw_seterrno (DWARF_E_NOMEM);
return;
}
memcpy (dwp_path, cu->dbg->elfpath, elfpath_len);
strcpy (dwp_path + elfpath_len, ".dwp");
int dwp_fd = open (dwp_path, O_RDONLY);
free (dwp_path);
if (dwp_fd != -1)
{
Dwarf *dwp_dwarf = dwarf_begin (dwp_fd, DWARF_C_READ);
/* There's no way to know whether we got the correct file until
we look up the unit, but it should at least be a dwp file. */
if (dwp_dwarf != NULL
&& (dwp_dwarf->sectiondata[IDX_debug_cu_index] != NULL
|| dwp_dwarf->sectiondata[IDX_debug_tu_index] != NULL))
{
cu->dbg->dwp_dwarf = dwp_dwarf;
cu->dbg->dwp_fd = dwp_fd;
}
else
close (dwp_fd);
}
}
if (cu->dbg->dwp_dwarf == NULL)
cu->dbg->dwp_dwarf = (Dwarf *) -1;
}
if (cu->dbg->dwp_dwarf != (Dwarf *) -1)
{
Dwarf_CU *split = __libdw_dwp_findcu_id (cu->dbg->dwp_dwarf,
cu->unit_id8);
if (split != NULL)
{
if (eu_tsearch (split->dbg, &cu->dbg->split_tree,
__libdw_finddbg_cb) == NULL)
{
/* Something went wrong. Don't link. */
__libdw_seterrno (DWARF_E_NOMEM);
return;
}
/* Link skeleton and split compile units. */
__libdw_link_skel_split (cu, split);
}
}
}
Dwarf_CU *
internal_function
__libdw_find_split_unit (Dwarf_CU *cu)
{
/* Set result before releasing the lock. */
Dwarf_CU *result;
rwlock_wrlock(cu->split_lock);
/* Only try once. */
if (cu->split != (Dwarf_CU *) -1)
{
result = cu->split;
rwlock_unlock(cu->split_lock);
return result;
}
/* We need a skeleton unit with a comp_dir and [GNU_]dwo_name attributes.
The split unit will be the first in the dwo file and should have the
same id as the skeleton. */
if (cu->unit_type == DW_UT_skeleton)
{
/* First, try the dwp file. */
try_dwp_file (cu);
Dwarf_Die cudie = CUDIE (cu);
Dwarf_Attribute dwo_name;
/* Try a dwo file. It is fine if dwo_dir doesn't exist, but then
dwo_name needs to be an absolute path. */
if (cu->split == (Dwarf_CU *) -1
&& (dwarf_attr (&cudie, DW_AT_dwo_name, &dwo_name) != NULL
|| dwarf_attr (&cudie, DW_AT_GNU_dwo_name, &dwo_name) != NULL))
{
/* Try the dwo file name in the same directory
as we found the skeleton file. */
const char *dwo_file = dwarf_formstring (&dwo_name);
const char *debugdir = cu->dbg->debugdir;
char *dwo_path = __libdw_filepath (debugdir, NULL, dwo_file);
if (dwo_path != NULL)
{
try_split_file (cu, dwo_path);
free (dwo_path);
}
if (cu->split == (Dwarf_CU *) -1)
{
/* Try compdir plus dwo_name. */
Dwarf_Attribute compdir;
dwarf_attr (&cudie, DW_AT_comp_dir, &compdir);
const char *dwo_dir = dwarf_formstring (&compdir);
if (dwo_dir != NULL)
{
dwo_path = __libdw_filepath (debugdir, dwo_dir, dwo_file);
if (dwo_path != NULL)
{
try_split_file (cu, dwo_path);
free (dwo_path);
}
}
}
/* XXX If still not found we could try stripping dirs from the
comp_dir and adding them from the comp_dir, assuming
someone moved a whole build tree around. */
}
}
/* If we found nothing, make sure we don't try again. */
if (cu->split == (Dwarf_CU *) -1)
cu->split = NULL;
result = cu->split;
rwlock_unlock(cu->split_lock);
return result;
}
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