gdb/solib-target.c - binutils-gdb - Git at Google

 /* Definitions for targets which report shared library events.

    Copyright (C) 2007-2025 Free Software Foundation, Inc.

    This file is part of GDB.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    This program 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 a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 #include "objfiles.h"
 #include "solib.h"
 #include "symtab.h"
 #include "symfile.h"
 #include "target.h"
 #include "solib-target.h"
 #include <vector>
 #include "inferior.h"

 /* Private data for each loaded library.  */
 struct lm_info_target final : public lm_info
 {
   /* The target can either specify segment bases or section bases, not
      both.  */

   /* The base addresses for each independently relocatable segment of
      this shared library.  */
   std::vector<CORE_ADDR> segment_bases;

   /* The base addresses for each independently allocatable,
      relocatable section of this shared library.  */
   std::vector<CORE_ADDR> section_bases;

   /* The cached offsets for each section of this shared library,
      determined from SEGMENT_BASES, or SECTION_BASES.  */
   section_offsets offsets;
 };

 using lm_info_target_up = std::unique_ptr<lm_info_target>;

 /* Type used to convey the information about one target library while parsing
    the XML.  */

 struct target_library
 {
   std::string name;
   lm_info_target_up info;
 };

 #if !defined(HAVE_LIBEXPAT)

 static std::vector<target_library>
 solib_target_parse_libraries (const char *library)
 {
   static int have_warned;

   if (!have_warned)
     {
       have_warned = 1;
       warning (_("Can not parse XML library list; XML support was disabled "
 		 "at compile time"));
     }

   return {};
 }

 #else /* HAVE_LIBEXPAT */

 #include "xml-support.h"

 /* Handle the start of a <segment> element.  */

 static void
 library_list_start_segment (struct gdb_xml_parser *parser,
 			    const struct gdb_xml_element *element,
 			    void *user_data,
 			    std::vector<gdb_xml_value> &attributes)
 {
   const auto list = static_cast<std::vector<target_library> *> (user_data);
   target_library &last = list->back ();
   ULONGEST *address_p
     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
   CORE_ADDR address = (CORE_ADDR) *address_p;

   if (!last.info->section_bases.empty ())
     gdb_xml_error (parser,
 		   _("Library list with both segments and sections"));

   last.info->segment_bases.push_back (address);
 }

 static void
 library_list_start_section (struct gdb_xml_parser *parser,
 			    const struct gdb_xml_element *element,
 			    void *user_data,
 			    std::vector<gdb_xml_value> &attributes)
 {
   const auto list = static_cast<std::vector<target_library> *> (user_data);
   target_library &last = list->back ();
   ULONGEST *address_p
     = (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
   CORE_ADDR address = (CORE_ADDR) *address_p;

   if (!last.info->segment_bases.empty ())
     gdb_xml_error (parser,
 		   _("Library list with both segments and sections"));

   last.info->section_bases.push_back (address);
 }

 /* Handle the start of a <library> element.  */

 static void
 library_list_start_library (struct gdb_xml_parser *parser,
 			    const struct gdb_xml_element *element,
 			    void *user_data,
 			    std::vector<gdb_xml_value> &attributes)
 {
   const auto list = static_cast<std::vector<target_library> *> (user_data);
   std::string name
     = (const char *) xml_find_attribute (attributes, "name")->value.get ();

   list->emplace_back (target_library { std::move (name),
 				       std::make_unique<lm_info_target> () });
 }

 static void
 library_list_end_library (struct gdb_xml_parser *parser,
 			  const struct gdb_xml_element *element,
 			  void *user_data, const char *body_text)
 {
   const auto list = static_cast<std::vector<target_library> *> (user_data);
   target_library &last = list->back ();

   if (last.info->segment_bases.empty () && last.info->section_bases.empty ())
     gdb_xml_error (parser, _("No segment or section bases defined"));
 }


 /* Handle the start of a <library-list> element.  */

 static void
 library_list_start_list (struct gdb_xml_parser *parser,
 			 const struct gdb_xml_element *element,
 			 void *user_data,
 			 std::vector<gdb_xml_value> &attributes)
 {
   struct gdb_xml_value *version = xml_find_attribute (attributes, "version");

   /* #FIXED attribute may be omitted, Expat returns NULL in such case.  */
   if (version != NULL)
     {
       const char *string = (const char *) version->value.get ();

       if (strcmp (string, "1.0") != 0)
 	gdb_xml_error (parser,
 		       _("Library list has unsupported version \"%s\""),
 		       string);
     }
 }

 /* The allowed elements and attributes for an XML library list.
    The root element is a <library-list>.  */

 static const struct gdb_xml_attribute segment_attributes[] = {
   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 };

 static const struct gdb_xml_attribute section_attributes[] = {
   { "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 };

 static const struct gdb_xml_element library_children[] = {
   { "segment", segment_attributes, NULL,
     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
     library_list_start_segment, NULL },
   { "section", section_attributes, NULL,
     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
     library_list_start_section, NULL },
   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 };

 static const struct gdb_xml_attribute library_attributes[] = {
   { "name", GDB_XML_AF_NONE, NULL, NULL },
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 };

 static const struct gdb_xml_element library_list_children[] = {
   { "library", library_attributes, library_children,
     GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
     library_list_start_library, library_list_end_library },
   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 };

 static const struct gdb_xml_attribute library_list_attributes[] = {
   { "version", GDB_XML_AF_OPTIONAL, NULL, NULL },
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 };

 static const struct gdb_xml_element library_list_elements[] = {
   { "library-list", library_list_attributes, library_list_children,
     GDB_XML_EF_NONE, library_list_start_list, NULL },
   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 };

 static std::vector<target_library>
 solib_target_parse_libraries (const char *library)
 {
   std::vector<target_library> result;

   if (gdb_xml_parse_quick (_("target library list"), "library-list.dtd",
 			   library_list_elements, library, &result) == 0)
     {
       /* Parsed successfully.  */
       return result;
     }

   result.clear ();
   return result;
 }
 #endif

 owning_intrusive_list<solib>
 target_solib_ops::current_sos () const
 {
   owning_intrusive_list<solib> sos;

   /* Fetch the list of shared libraries.  */
   std::optional<gdb::char_vector> library_document
     = target_read_stralloc (current_inferior ()->top_target (),
 			    TARGET_OBJECT_LIBRARIES, NULL);
   if (!library_document)
     return {};

   /* Parse the list.  */
   std::vector<target_library> library_list
     = solib_target_parse_libraries (library_document->data ());

   /* Build a struct solib for each entry on the list.  */
   for (auto &library : library_list)
     sos.emplace_back (std::move (library.info), library.name, library.name,
 		      *this);

   return sos;
 }

 void
 target_solib_ops::relocate_section_addresses (solib &so,
 					      target_section *sec) const
 {
   CORE_ADDR offset;
   auto *li = gdb::checked_static_cast<lm_info_target *> (so.lm_info.get ());

   /* Build the offset table only once per object file.  We can not do
      it any earlier, since we need to open the file first.  */
   if (li->offsets.empty ())
     {
       int num_sections = gdb_bfd_count_sections (so.abfd.get ());

       li->offsets.assign (num_sections, 0);

       if (!li->section_bases.empty ())
 	{
 	  int i;
 	  asection *sect;
 	  int num_alloc_sections = 0;

 	  for (i = 0, sect = so.abfd->sections;
 	       sect != NULL;
 	       i++, sect = sect->next)
 	    if ((bfd_section_flags (sect) & SEC_ALLOC))
 	      num_alloc_sections++;

 	  if (num_alloc_sections != li->section_bases.size ())
 	    warning (_("\
 Could not relocate shared library \"%s\": wrong number of ALLOC sections"),
 		     so.name.c_str ());
 	  else
 	    {
 	      int bases_index = 0;
 	      int found_range = 0;

 	      so.addr_low = ~(CORE_ADDR) 0;
 	      so.addr_high = 0;
 	      for (i = 0, sect = so.abfd->sections;
 		   sect != NULL;
 		   i++, sect = sect->next)
 		{
 		  if (!(bfd_section_flags (sect) & SEC_ALLOC))
 		    continue;
 		  if (bfd_section_size (sect) > 0)
 		    {
 		      CORE_ADDR low, high;

 		      low = li->section_bases[i];
 		      high = low + bfd_section_size (sect) - 1;

 		      if (low < so.addr_low)
 			so.addr_low = low;
 		      if (high > so.addr_high)
 			so.addr_high = high;
 		      gdb_assert (so.addr_low <= so.addr_high);
 		      found_range = 1;
 		    }
 		  li->offsets[i] = li->section_bases[bases_index];
 		  bases_index++;
 		}
 	      if (!found_range)
 		so.addr_low = so.addr_high = 0;
 	      gdb_assert (so.addr_low <= so.addr_high);
 	    }
 	}
       else if (!li->segment_bases.empty ())
 	{
 	  symfile_segment_data_up data
 	    = get_symfile_segment_data (so.abfd.get ());

 	  if (data == NULL)
 	    warning (_("\
 Could not relocate shared library \"%s\": no segments"), so.name.c_str ());
 	  else
 	    {
 	      ULONGEST orig_delta;
 	      int i;

 	      if (!symfile_map_offsets_to_segments (so.abfd.get (), data.get (),
 						    li->offsets,
 						    li->segment_bases.size (),
 						    li->segment_bases.data ()))
 		warning (_("\
 Could not relocate shared library \"%s\": bad offsets"), so.name.c_str ());

 	      /* Find the range of addresses to report for this library in
 		 "info sharedlibrary".  Report any consecutive segments
 		 which were relocated as a single unit.  */
 	      gdb_assert (li->segment_bases.size () > 0);
 	      orig_delta = li->segment_bases[0] - data->segments[0].base;

 	      for (i = 1; i < data->segments.size (); i++)
 		{
 		  /* If we have run out of offsets, assume all
 		     remaining segments have the same offset.  */
 		  if (i >= li->segment_bases.size ())
 		    continue;

 		  /* If this segment does not have the same offset, do
 		     not include it in the library's range.  */
 		  if (li->segment_bases[i] - data->segments[i].base
 		      != orig_delta)
 		    break;
 		}

 	      so.addr_low = li->segment_bases[0];
 	      so.addr_high = (data->segments[i - 1].base
 			       + data->segments[i - 1].size
 			       + orig_delta);
 	      gdb_assert (so.addr_low <= so.addr_high);
 	    }
 	}
     }

   offset = li->offsets[gdb_bfd_section_index (sec->the_bfd_section->owner,
 					      sec->the_bfd_section)];
   sec->addr += offset;
   sec->endaddr += offset;
 }

 bool
 target_solib_ops::in_dynsym_resolve_code (CORE_ADDR pc) const
 {
   /* We don't have a range of addresses for the dynamic linker; there
      may not be one in the program's address space.  So only report
      PLT entries (which may be import stubs).  */
   return in_plt_section (pc);
 }

 /* See solib-target.h.  */

 solib_ops_up
 make_target_solib_ops (program_space *pspace)
 {
   return std::make_unique<target_solib_ops> (pspace);
 }
	/* Definitions for targets which report shared library events.

	Copyright (C) 2007-2025 Free Software Foundation, Inc.

	This file is part of GDB.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 3 of the License, or
	(at your option) any later version.

	This program 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 a copy of the GNU General Public License
	along with this program. If not, see <http://www.gnu.org/licenses/>. */

	#include "objfiles.h"
	#include "solib.h"
	#include "symtab.h"
	#include "symfile.h"
	#include "target.h"
	#include "solib-target.h"
	#include <vector>
	#include "inferior.h"

	/* Private data for each loaded library. */
	struct lm_info_target final : public lm_info
	{
	/* The target can either specify segment bases or section bases, not
	both. */

	/* The base addresses for each independently relocatable segment of
	this shared library. */
	std::vector<CORE_ADDR> segment_bases;

	/* The base addresses for each independently allocatable,
	relocatable section of this shared library. */
	std::vector<CORE_ADDR> section_bases;

	/* The cached offsets for each section of this shared library,
	determined from SEGMENT_BASES, or SECTION_BASES. */
	section_offsets offsets;
	};

	using lm_info_target_up = std::unique_ptr<lm_info_target>;

	/* Type used to convey the information about one target library while parsing
	the XML. */

	struct target_library
	{
	std::string name;
	lm_info_target_up info;
	};

	#if !defined(HAVE_LIBEXPAT)

	static std::vector<target_library>
	solib_target_parse_libraries (const char *library)
	{
	static int have_warned;

	if (!have_warned)
	{
	have_warned = 1;
	warning (_("Can not parse XML library list; XML support was disabled "
	"at compile time"));
	}

	return {};
	}

	#else /* HAVE_LIBEXPAT */

	#include "xml-support.h"

	/* Handle the start of a <segment> element. */

	static void
	library_list_start_segment (struct gdb_xml_parser *parser,
	const struct gdb_xml_element *element,
	void *user_data,
	std::vector<gdb_xml_value> &attributes)
	{
	const auto list = static_cast<std::vector<target_library> *> (user_data);
	target_library &last = list->back ();
	ULONGEST *address_p
	= (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
	CORE_ADDR address = (CORE_ADDR) *address_p;

	if (!last.info->section_bases.empty ())
	gdb_xml_error (parser,
	_("Library list with both segments and sections"));

	last.info->segment_bases.push_back (address);
	}

	static void
	library_list_start_section (struct gdb_xml_parser *parser,
	const struct gdb_xml_element *element,
	void *user_data,
	std::vector<gdb_xml_value> &attributes)
	{
	const auto list = static_cast<std::vector<target_library> *> (user_data);
	target_library &last = list->back ();
	ULONGEST *address_p
	= (ULONGEST *) xml_find_attribute (attributes, "address")->value.get ();
	CORE_ADDR address = (CORE_ADDR) *address_p;

	if (!last.info->segment_bases.empty ())
	gdb_xml_error (parser,
	_("Library list with both segments and sections"));

	last.info->section_bases.push_back (address);
	}

	/* Handle the start of a <library> element. */

	static void
	library_list_start_library (struct gdb_xml_parser *parser,
	const struct gdb_xml_element *element,
	void *user_data,
	std::vector<gdb_xml_value> &attributes)
	{
	const auto list = static_cast<std::vector<target_library> *> (user_data);
	std::string name
	= (const char *) xml_find_attribute (attributes, "name")->value.get ();

	list->emplace_back (target_library { std::move (name),
	std::make_unique<lm_info_target> () });
	}

	static void
	library_list_end_library (struct gdb_xml_parser *parser,
	const struct gdb_xml_element *element,
	void user_data, const char body_text)
	{
	const auto list = static_cast<std::vector<target_library> *> (user_data);
	target_library &last = list->back ();

	if (last.info->segment_bases.empty () && last.info->section_bases.empty ())
	gdb_xml_error (parser, _("No segment or section bases defined"));
	}


	/* Handle the start of a <library-list> element. */

	static void
	library_list_start_list (struct gdb_xml_parser *parser,
	const struct gdb_xml_element *element,
	void *user_data,
	std::vector<gdb_xml_value> &attributes)
	{
	struct gdb_xml_value *version = xml_find_attribute (attributes, "version");

	/* #FIXED attribute may be omitted, Expat returns NULL in such case. */
	if (version != NULL)
	{
	const char string = (const char ) version->value.get ();

	if (strcmp (string, "1.0") != 0)
	gdb_xml_error (parser,
	_("Library list has unsupported version \"%s\""),
	string);
	}
	}

	/* The allowed elements and attributes for an XML library list.
	The root element is a <library-list>. */

	static const struct gdb_xml_attribute segment_attributes[] = {
	{ "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
	{ NULL, GDB_XML_AF_NONE, NULL, NULL }
	};

	static const struct gdb_xml_attribute section_attributes[] = {
	{ "address", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
	{ NULL, GDB_XML_AF_NONE, NULL, NULL }
	};

	static const struct gdb_xml_element library_children[] = {
	{ "segment", segment_attributes, NULL,
	GDB_XML_EF_REPEATABLE \| GDB_XML_EF_OPTIONAL,
	library_list_start_segment, NULL },
	{ "section", section_attributes, NULL,
	GDB_XML_EF_REPEATABLE \| GDB_XML_EF_OPTIONAL,
	library_list_start_section, NULL },
	{ NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
	};

	static const struct gdb_xml_attribute library_attributes[] = {
	{ "name", GDB_XML_AF_NONE, NULL, NULL },
	{ NULL, GDB_XML_AF_NONE, NULL, NULL }
	};

	static const struct gdb_xml_element library_list_children[] = {
	{ "library", library_attributes, library_children,
	GDB_XML_EF_REPEATABLE \| GDB_XML_EF_OPTIONAL,
	library_list_start_library, library_list_end_library },
	{ NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
	};

	static const struct gdb_xml_attribute library_list_attributes[] = {
	{ "version", GDB_XML_AF_OPTIONAL, NULL, NULL },
	{ NULL, GDB_XML_AF_NONE, NULL, NULL }
	};

	static const struct gdb_xml_element library_list_elements[] = {
	{ "library-list", library_list_attributes, library_list_children,
	GDB_XML_EF_NONE, library_list_start_list, NULL },
	{ NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
	};

	static std::vector<target_library>
	solib_target_parse_libraries (const char *library)
	{
	std::vector<target_library> result;

	if (gdb_xml_parse_quick (_("target library list"), "library-list.dtd",
	library_list_elements, library, &result) == 0)
	{
	/* Parsed successfully. */
	return result;
	}

	result.clear ();
	return result;
	}
	#endif

	owning_intrusive_list<solib>
	target_solib_ops::current_sos () const
	{
	owning_intrusive_list<solib> sos;

	/* Fetch the list of shared libraries. */
	std::optional<gdb::char_vector> library_document
	= target_read_stralloc (current_inferior ()->top_target (),
	TARGET_OBJECT_LIBRARIES, NULL);
	if (!library_document)
	return {};

	/* Parse the list. */
	std::vector<target_library> library_list
	= solib_target_parse_libraries (library_document->data ());

	/* Build a struct solib for each entry on the list. */
	for (auto &library : library_list)
	sos.emplace_back (std::move (library.info), library.name, library.name,
	*this);

	return sos;
	}

	void
	target_solib_ops::relocate_section_addresses (solib &so,
	target_section *sec) const
	{
	CORE_ADDR offset;
	auto li = gdb::checked_static_cast<lm_info_target > (so.lm_info.get ());

	/* Build the offset table only once per object file. We can not do
	it any earlier, since we need to open the file first. */
	if (li->offsets.empty ())
	{
	int num_sections = gdb_bfd_count_sections (so.abfd.get ());

	li->offsets.assign (num_sections, 0);

	if (!li->section_bases.empty ())
	{
	int i;
	asection *sect;
	int num_alloc_sections = 0;

	for (i = 0, sect = so.abfd->sections;
	sect != NULL;
	i++, sect = sect->next)
	if ((bfd_section_flags (sect) & SEC_ALLOC))
	num_alloc_sections++;

	if (num_alloc_sections != li->section_bases.size ())
	warning (_("\
	Could not relocate shared library \"%s\": wrong number of ALLOC sections"),
	so.name.c_str ());
	else
	{
	int bases_index = 0;
	int found_range = 0;

	so.addr_low = ~(CORE_ADDR) 0;
	so.addr_high = 0;
	for (i = 0, sect = so.abfd->sections;
	sect != NULL;
	i++, sect = sect->next)
	{
	if (!(bfd_section_flags (sect) & SEC_ALLOC))
	continue;
	if (bfd_section_size (sect) > 0)
	{
	CORE_ADDR low, high;

	low = li->section_bases[i];
	high = low + bfd_section_size (sect) - 1;

	if (low < so.addr_low)
	so.addr_low = low;
	if (high > so.addr_high)
	so.addr_high = high;
	gdb_assert (so.addr_low <= so.addr_high);
	found_range = 1;
	}
	li->offsets[i] = li->section_bases[bases_index];
	bases_index++;
	}
	if (!found_range)
	so.addr_low = so.addr_high = 0;
	gdb_assert (so.addr_low <= so.addr_high);
	}
	}
	else if (!li->segment_bases.empty ())
	{
	symfile_segment_data_up data
	= get_symfile_segment_data (so.abfd.get ());

	if (data == NULL)
	warning (_("\
	Could not relocate shared library \"%s\": no segments"), so.name.c_str ());
	else
	{
	ULONGEST orig_delta;
	int i;

	if (!symfile_map_offsets_to_segments (so.abfd.get (), data.get (),
	li->offsets,
	li->segment_bases.size (),
	li->segment_bases.data ()))
	warning (_("\
	Could not relocate shared library \"%s\": bad offsets"), so.name.c_str ());

	/* Find the range of addresses to report for this library in
	"info sharedlibrary". Report any consecutive segments
	which were relocated as a single unit. */
	gdb_assert (li->segment_bases.size () > 0);
	orig_delta = li->segment_bases[0] - data->segments[0].base;

	for (i = 1; i < data->segments.size (); i++)
	{
	/* If we have run out of offsets, assume all
	remaining segments have the same offset. */
	if (i >= li->segment_bases.size ())
	continue;

	/* If this segment does not have the same offset, do
	not include it in the library's range. */
	if (li->segment_bases[i] - data->segments[i].base
	!= orig_delta)
	break;
	}

	so.addr_low = li->segment_bases[0];
	so.addr_high = (data->segments[i - 1].base
	+ data->segments[i - 1].size
	+ orig_delta);
	gdb_assert (so.addr_low <= so.addr_high);
	}
	}
	}

	offset = li->offsets[gdb_bfd_section_index (sec->the_bfd_section->owner,
	sec->the_bfd_section)];
	sec->addr += offset;
	sec->endaddr += offset;
	}

	bool
	target_solib_ops::in_dynsym_resolve_code (CORE_ADDR pc) const
	{
	/* We don't have a range of addresses for the dynamic linker; there
	may not be one in the program's address space. So only report
	PLT entries (which may be import stubs). */
	return in_plt_section (pc);
	}

	/* See solib-target.h. */

	solib_ops_up
	make_target_solib_ops (program_space *pspace)
	{
	return std::make_unique<target_solib_ops> (pspace);
	}