gdb/debuginfod-support.c - third_party/binutils-gdb - Git at Google

 /* debuginfod utilities for GDB.
    Copyright (C) 2020-2023 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 "defs.h"
 #include "diagnostics.h"
 #include <errno.h>
 #include "gdbsupport/scoped_fd.h"
 #include "debuginfod-support.h"
 #include "gdbsupport/gdb_optional.h"
 #include "cli/cli-cmds.h"
 #include "cli/cli-style.h"
 #include "cli-out.h"
 #include "target.h"

 /* Set/show debuginfod commands.  */
 static cmd_list_element *set_debuginfod_prefix_list;
 static cmd_list_element *show_debuginfod_prefix_list;

 static const char debuginfod_on[] = "on";
 static const char debuginfod_off[] = "off";
 static const char debuginfod_ask[] = "ask";

 static const char *debuginfod_enabled_enum[]
   = { debuginfod_on, debuginfod_off, debuginfod_ask, nullptr };

 static const char *debuginfod_enabled =
 #if defined(HAVE_LIBDEBUGINFOD)
   debuginfod_ask;
 #else
   debuginfod_off;
 #endif

 static unsigned int debuginfod_verbose = 1;

 #ifndef HAVE_LIBDEBUGINFOD
 scoped_fd
 debuginfod_source_query (const unsigned char *build_id, int build_id_len,
 			 const char *srcpath,
 			 gdb::unique_xmalloc_ptr<char> *destname)
 {
   return scoped_fd (-ENOSYS);
 }

 scoped_fd
 debuginfod_debuginfo_query (const unsigned char *build_id, int build_id_len,
 			    const char *filename,
 			    gdb::unique_xmalloc_ptr<char> *destname)
 {
   return scoped_fd (-ENOSYS);
 }

 scoped_fd
 debuginfod_exec_query (const unsigned char *build_id, int build_id_len,
 		       const char *filename,
 		       gdb::unique_xmalloc_ptr<char> *destname)
 {
   return scoped_fd (-ENOSYS);
 }

 #define NO_IMPL _ ("Support for debuginfod is not compiled into GDB.")

 #else
 #include <elfutils/debuginfod.h>

 struct user_data
 {
   user_data (const char *desc, const char *fname)
     : desc (desc),
       fname (fname)
   {
   }

   const char *const desc;
   const char *const fname;
   ui_out::progress_update progress;
 };

 /* Deleter for a debuginfod_client.  */

 struct debuginfod_client_deleter
 {
   void operator() (debuginfod_client *c) { debuginfod_end (c); }
 };

 using debuginfod_client_up
   = std::unique_ptr<debuginfod_client, debuginfod_client_deleter>;

 /* Convert SIZE into a unit suitable for use with progress updates.
    SIZE should in given in bytes and will be converted into KB, MB, GB
    or remain unchanged. UNIT will be set to "B", "KB", "MB" or "GB"
    accordingly.  */

 static const char *
 get_size_and_unit (double &size)
 {
   if (size < 1024)
     /* If size is less than 1 KB then set unit to B.  */
     return "B";

   size /= 1024;
   if (size < 1024)
     /* If size is less than 1 MB then set unit to KB.  */
     return "K";

   size /= 1024;
   if (size < 1024)
     /* If size is less than 1 GB then set unit to MB.  */
     return "M";

   size /= 1024;
   return "G";
 }

 static int
 progressfn (debuginfod_client *c, long cur, long total)
 {
   user_data *data = static_cast<user_data *> (debuginfod_get_user_data (c));
   gdb_assert (data != nullptr);

   string_file styled_fname (current_uiout->can_emit_style_escape ());
   fprintf_styled (&styled_fname, file_name_style.style (), "%s", data->fname);

   if (check_quit_flag ())
     {
       gdb_printf ("Cancelling download of %s %s...\n", data->desc,
 		  styled_fname.c_str ());
       return 1;
     }

   if (debuginfod_verbose == 0)
     return 0;

   /* Print progress update.  Include the transfer size if available.  */
   if (total > 0)
     {
       /* Transfer size is known.  */
       double howmuch = (double) cur / (double) total;

       if (howmuch >= 0.0 && howmuch <= 1.0)
 	{
 	  double d_total = (double) total;
 	  const char *unit = get_size_and_unit (d_total);
 	  std::string msg
 	    = string_printf ("Downloading %0.2f %s %s %s", d_total, unit,
 			     data->desc, styled_fname.c_str ());
 	  data->progress.update_progress (msg, unit, howmuch, d_total);
 	  return 0;
 	}
     }

   std::string msg
     = string_printf ("Downloading %s %s", data->desc, styled_fname.c_str ());
   data->progress.update_progress (msg);
   return 0;
 }

 static debuginfod_client *
 get_debuginfod_client ()
 {
   static debuginfod_client_up global_client;

   if (global_client == nullptr)
     {
       global_client.reset (debuginfod_begin ());

       if (global_client != nullptr)
 	debuginfod_set_progressfn (global_client.get (), progressfn);
     }

   return global_client.get ();
 }

 /* Check if debuginfod is enabled.  If configured to do so, ask the user
    whether to enable debuginfod.  */

 static bool
 debuginfod_is_enabled ()
 {
   const char *urls = skip_spaces (getenv (DEBUGINFOD_URLS_ENV_VAR));

   if (debuginfod_enabled == debuginfod_off || urls == nullptr || *urls == '\0')
     return false;

   if (debuginfod_enabled == debuginfod_ask)
     {
       gdb_printf (_ ("\nThis GDB supports auto-downloading debuginfo "
 		     "from the following URLs:\n"));

       gdb::string_view url_view (urls);
       while (true)
 	{
 	  size_t off = url_view.find_first_not_of (' ');
 	  if (off == gdb::string_view::npos)
 	    break;
 	  url_view = url_view.substr (off);
 	  /* g++ 11.2.1 on s390x, g++ 11.3.1 on ppc64le and g++ 11 on
 	     hppa seem convinced url_view might be of SIZE_MAX length.
 	     And so complains because the length of an array can only
 	     be PTRDIFF_MAX.  */
 	  DIAGNOSTIC_PUSH
 	  DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD
 	  off = url_view.find_first_of (' ');
 	  DIAGNOSTIC_POP
 	  gdb_printf (_ ("  <%ps>\n"),
 		      styled_string (
 			file_name_style.style (),
 			gdb::to_string (url_view.substr (0, off)).c_str ()));
 	  if (off == gdb::string_view::npos)
 	    break;
 	  url_view = url_view.substr (off);
 	}

       int resp = nquery (_ ("Enable debuginfod for this session? "));
       if (!resp)
 	{
 	  gdb_printf (_ ("Debuginfod has been disabled.\nTo make this "
 			 "setting permanent, add \'set debuginfod "
 			 "enabled off\' to .gdbinit.\n"));
 	  debuginfod_enabled = debuginfod_off;
 	  return false;
 	}

       gdb_printf (_ ("Debuginfod has been enabled.\nTo make this "
 		     "setting permanent, add \'set debuginfod enabled "
 		     "on\' to .gdbinit.\n"));
       debuginfod_enabled = debuginfod_on;
     }

   return true;
 }

 /* Print the result of the most recent attempted download.  */

 static void
 print_outcome (user_data &data, int fd)
 {
   /* Clears the current line of progress output.  */
   current_uiout->do_progress_end ();

   if (fd < 0 && fd != -ENOENT)
     gdb_printf (_ ("Download failed: %s.  Continuing without %s %ps.\n"),
 		safe_strerror (-fd), data.desc,
 		styled_string (file_name_style.style (), data.fname));
 }

 /* See debuginfod-support.h  */

 scoped_fd
 debuginfod_source_query (const unsigned char *build_id, int build_id_len,
 			 const char *srcpath,
 			 gdb::unique_xmalloc_ptr<char> *destname)
 {
   if (!debuginfod_is_enabled ())
     return scoped_fd (-ENOSYS);

   debuginfod_client *c = get_debuginfod_client ();

   if (c == nullptr)
     return scoped_fd (-ENOMEM);

   char *dname = nullptr;
   user_data data ("source file", srcpath);

   debuginfod_set_user_data (c, &data);
   gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
   if (target_supports_terminal_ours ())
     {
       term_state.emplace ();
       target_terminal::ours ();
     }

   scoped_fd fd (debuginfod_find_source (c, build_id, build_id_len, srcpath,
 					&dname));
   debuginfod_set_user_data (c, nullptr);
   print_outcome (data, fd.get ());

   if (fd.get () >= 0)
     destname->reset (dname);

   return fd;
 }

 /* See debuginfod-support.h  */

 scoped_fd
 debuginfod_debuginfo_query (const unsigned char *build_id, int build_id_len,
 			    const char *filename,
 			    gdb::unique_xmalloc_ptr<char> *destname)
 {
   if (!debuginfod_is_enabled ())
     return scoped_fd (-ENOSYS);

   debuginfod_client *c = get_debuginfod_client ();

   if (c == nullptr)
     return scoped_fd (-ENOMEM);

   char *dname = nullptr;
   user_data data ("separate debug info for", filename);

   debuginfod_set_user_data (c, &data);
   gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
   if (target_supports_terminal_ours ())
     {
       term_state.emplace ();
       target_terminal::ours ();
     }

   scoped_fd fd (debuginfod_find_debuginfo (c, build_id, build_id_len, &dname));
   debuginfod_set_user_data (c, nullptr);
   print_outcome (data, fd.get ());

   if (fd.get () >= 0)
     destname->reset (dname);

   return fd;
 }

 /* See debuginfod-support.h  */

 scoped_fd
 debuginfod_exec_query (const unsigned char *build_id, int build_id_len,
 		       const char *filename,
 		       gdb::unique_xmalloc_ptr<char> *destname)
 {
   if (!debuginfod_is_enabled ())
     return scoped_fd (-ENOSYS);

   debuginfod_client *c = get_debuginfod_client ();

   if (c == nullptr)
     return scoped_fd (-ENOMEM);

   char *dname = nullptr;
   user_data data ("executable for", filename);

   debuginfod_set_user_data (c, &data);
   gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
   if (target_supports_terminal_ours ())
     {
       term_state.emplace ();
       target_terminal::ours ();
     }

   scoped_fd fd (debuginfod_find_executable (c, build_id, build_id_len,
 					    &dname));
   debuginfod_set_user_data (c, nullptr);
   print_outcome (data, fd.get ());

   if (fd.get () >= 0)
     destname->reset (dname);

   return fd;
 }
 #endif

 /* Set callback for "set debuginfod enabled".  */

 static void
 set_debuginfod_enabled (const char *value)
 {
 #if defined(HAVE_LIBDEBUGINFOD)
   debuginfod_enabled = value;
 #else
   /* Disabling debuginfod when gdb is not built with it is a no-op.  */
   if (value != debuginfod_off)
     error (NO_IMPL);
 #endif
 }

 /* Get callback for "set debuginfod enabled".  */

 static const char *
 get_debuginfod_enabled ()
 {
   return debuginfod_enabled;
 }

 /* Show callback for "set debuginfod enabled".  */

 static void
 show_debuginfod_enabled (ui_file *file, int from_tty, cmd_list_element *cmd,
 			 const char *value)
 {
   gdb_printf (file,
 	      _ ("Debuginfod functionality is currently set to "
 		 "\"%s\".\n"),
 	      debuginfod_enabled);
 }

 /* Set callback for "set debuginfod urls".  */

 static void
 set_debuginfod_urls (const std::string &urls)
 {
 #if defined(HAVE_LIBDEBUGINFOD)
   if (setenv (DEBUGINFOD_URLS_ENV_VAR, urls.c_str (), 1) != 0)
     warning (_ ("Unable to set debuginfod URLs: %s"), safe_strerror (errno));
 #else
   error (NO_IMPL);
 #endif
 }

 /* Get callback for "set debuginfod urls".  */

 static const std::string &
 get_debuginfod_urls ()
 {
   static std::string urls;
 #if defined(HAVE_LIBDEBUGINFOD)
   const char *envvar = getenv (DEBUGINFOD_URLS_ENV_VAR);

   if (envvar != nullptr)
     urls = envvar;
   else
     urls.clear ();
 #endif

   return urls;
 }

 /* Show callback for "set debuginfod urls".  */

 static void
 show_debuginfod_urls (ui_file *file, int from_tty, cmd_list_element *cmd,
 		      const char *value)
 {
   if (value[0] == '\0')
     gdb_printf (file, _ ("Debuginfod URLs have not been set.\n"));
   else
     gdb_printf (file, _ ("Debuginfod URLs are currently set to:\n%s\n"),
 		value);
 }

 /* Show callback for "set debuginfod verbose".  */

 static void
 show_debuginfod_verbose_command (ui_file *file, int from_tty,
 				 cmd_list_element *cmd, const char *value)
 {
   gdb_printf (file, _ ("Debuginfod verbose output is set to %s.\n"), value);
 }

 /* Register debuginfod commands.  */

 void _initialize_debuginfod ();

 void
 _initialize_debuginfod ()
 {
   /* set/show debuginfod */
   add_setshow_prefix_cmd ("debuginfod", class_run,
 			  _ ("Set debuginfod options."),
 			  _ ("Show debuginfod options."),
 			  &set_debuginfod_prefix_list,
 			  &show_debuginfod_prefix_list, &setlist, &showlist);

   add_setshow_enum_cmd ("enabled", class_run, debuginfod_enabled_enum,
 			_ ("Set whether to use debuginfod."),
 			_ ("Show whether to use debuginfod."), _ ("\
 When on, enable the use of debuginfod to download missing debug info and\n\
 source files."),
 			set_debuginfod_enabled, get_debuginfod_enabled,
 			show_debuginfod_enabled, &set_debuginfod_prefix_list,
 			&show_debuginfod_prefix_list);

   /* set/show debuginfod urls */
   add_setshow_string_noescape_cmd ("urls", class_run, _ ("\
 Set the list of debuginfod server URLs."),
 				   _ ("\
 Show the list of debuginfod server URLs."),
 				   _ ("\
 Manage the space-separated list of debuginfod server URLs that GDB will query \
 when missing debuginfo, executables or source files.\nThe default value is \
 copied from the DEBUGINFOD_URLS environment variable."),
 				   set_debuginfod_urls, get_debuginfod_urls,
 				   show_debuginfod_urls,
 				   &set_debuginfod_prefix_list,
 				   &show_debuginfod_prefix_list);

   /* set/show debuginfod verbose */
   add_setshow_zuinteger_cmd ("verbose", class_support, &debuginfod_verbose,
 			     _ ("\
 Set verbosity of debuginfod output."),
 			     _ ("\
 Show debuginfod debugging."),
 			     _ ("\
 When set to a non-zero value, display verbose output for each debuginfod \
 query.\nTo disable, set to zero.  Verbose output is displayed by default."),
 			     nullptr, show_debuginfod_verbose_command,
 			     &set_debuginfod_prefix_list,
 			     &show_debuginfod_prefix_list);
 }
	/* debuginfod utilities for GDB.
	Copyright (C) 2020-2023 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 "defs.h"
	#include "diagnostics.h"
	#include <errno.h>
	#include "gdbsupport/scoped_fd.h"
	#include "debuginfod-support.h"
	#include "gdbsupport/gdb_optional.h"
	#include "cli/cli-cmds.h"
	#include "cli/cli-style.h"
	#include "cli-out.h"
	#include "target.h"

	/* Set/show debuginfod commands. */
	static cmd_list_element *set_debuginfod_prefix_list;
	static cmd_list_element *show_debuginfod_prefix_list;

	static const char debuginfod_on[] = "on";
	static const char debuginfod_off[] = "off";
	static const char debuginfod_ask[] = "ask";

	static const char *debuginfod_enabled_enum[]
	= { debuginfod_on, debuginfod_off, debuginfod_ask, nullptr };

	static const char *debuginfod_enabled =
	#if defined(HAVE_LIBDEBUGINFOD)
	debuginfod_ask;
	#else
	debuginfod_off;
	#endif

	static unsigned int debuginfod_verbose = 1;

	#ifndef HAVE_LIBDEBUGINFOD
	scoped_fd
	debuginfod_source_query (const unsigned char *build_id, int build_id_len,
	const char *srcpath,
	gdb::unique_xmalloc_ptr<char> *destname)
	{
	return scoped_fd (-ENOSYS);
	}

	scoped_fd
	debuginfod_debuginfo_query (const unsigned char *build_id, int build_id_len,
	const char *filename,
	gdb::unique_xmalloc_ptr<char> *destname)
	{
	return scoped_fd (-ENOSYS);
	}

	scoped_fd
	debuginfod_exec_query (const unsigned char *build_id, int build_id_len,
	const char *filename,
	gdb::unique_xmalloc_ptr<char> *destname)
	{
	return scoped_fd (-ENOSYS);
	}

	#define NO_IMPL _ ("Support for debuginfod is not compiled into GDB.")

	#else
	#include <elfutils/debuginfod.h>

	struct user_data
	{
	user_data (const char desc, const char fname)
	: desc (desc),
	fname (fname)
	{
	}

	const char *const desc;
	const char *const fname;
	ui_out::progress_update progress;
	};

	/* Deleter for a debuginfod_client. */

	struct debuginfod_client_deleter
	{
	void operator() (debuginfod_client *c) { debuginfod_end (c); }
	};

	using debuginfod_client_up
	= std::unique_ptr<debuginfod_client, debuginfod_client_deleter>;

	/* Convert SIZE into a unit suitable for use with progress updates.
	SIZE should in given in bytes and will be converted into KB, MB, GB
	or remain unchanged. UNIT will be set to "B", "KB", "MB" or "GB"
	accordingly. */

	static const char *
	get_size_and_unit (double &size)
	{
	if (size < 1024)
	/* If size is less than 1 KB then set unit to B. */
	return "B";

	size /= 1024;
	if (size < 1024)
	/* If size is less than 1 MB then set unit to KB. */
	return "K";

	size /= 1024;
	if (size < 1024)
	/* If size is less than 1 GB then set unit to MB. */
	return "M";

	size /= 1024;
	return "G";
	}

	static int
	progressfn (debuginfod_client *c, long cur, long total)
	{
	user_data data = static_cast<user_data > (debuginfod_get_user_data (c));
	gdb_assert (data != nullptr);

	string_file styled_fname (current_uiout->can_emit_style_escape ());
	fprintf_styled (&styled_fname, file_name_style.style (), "%s", data->fname);

	if (check_quit_flag ())
	{
	gdb_printf ("Cancelling download of %s %s...\n", data->desc,
	styled_fname.c_str ());
	return 1;
	}

	if (debuginfod_verbose == 0)
	return 0;

	/* Print progress update. Include the transfer size if available. */
	if (total > 0)
	{
	/* Transfer size is known. */
	double howmuch = (double) cur / (double) total;

	if (howmuch >= 0.0 && howmuch <= 1.0)
	{
	double d_total = (double) total;
	const char *unit = get_size_and_unit (d_total);
	std::string msg
	= string_printf ("Downloading %0.2f %s %s %s", d_total, unit,
	data->desc, styled_fname.c_str ());
	data->progress.update_progress (msg, unit, howmuch, d_total);
	return 0;
	}
	}

	std::string msg
	= string_printf ("Downloading %s %s", data->desc, styled_fname.c_str ());
	data->progress.update_progress (msg);
	return 0;
	}

	static debuginfod_client *
	get_debuginfod_client ()
	{
	static debuginfod_client_up global_client;

	if (global_client == nullptr)
	{
	global_client.reset (debuginfod_begin ());

	if (global_client != nullptr)
	debuginfod_set_progressfn (global_client.get (), progressfn);
	}

	return global_client.get ();
	}

	/* Check if debuginfod is enabled. If configured to do so, ask the user
	whether to enable debuginfod. */

	static bool
	debuginfod_is_enabled ()
	{
	const char *urls = skip_spaces (getenv (DEBUGINFOD_URLS_ENV_VAR));

	if (debuginfod_enabled == debuginfod_off \|\| urls == nullptr \|\| *urls == '\0')
	return false;

	if (debuginfod_enabled == debuginfod_ask)
	{
	gdb_printf (_ ("\nThis GDB supports auto-downloading debuginfo "
	"from the following URLs:\n"));

	gdb::string_view url_view (urls);
	while (true)
	{
	size_t off = url_view.find_first_not_of (' ');
	if (off == gdb::string_view::npos)
	break;
	url_view = url_view.substr (off);
	/* g++ 11.2.1 on s390x, g++ 11.3.1 on ppc64le and g++ 11 on
	hppa seem convinced url_view might be of SIZE_MAX length.
	And so complains because the length of an array can only
	be PTRDIFF_MAX. */
	DIAGNOSTIC_PUSH
	DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD
	off = url_view.find_first_of (' ');
	DIAGNOSTIC_POP
	gdb_printf (_ (" <%ps>\n"),
	styled_string (
	file_name_style.style (),
	gdb::to_string (url_view.substr (0, off)).c_str ()));
	if (off == gdb::string_view::npos)
	break;
	url_view = url_view.substr (off);
	}

	int resp = nquery (_ ("Enable debuginfod for this session? "));
	if (!resp)
	{
	gdb_printf (_ ("Debuginfod has been disabled.\nTo make this "
	"setting permanent, add \'set debuginfod "
	"enabled off\' to .gdbinit.\n"));
	debuginfod_enabled = debuginfod_off;
	return false;
	}

	gdb_printf (_ ("Debuginfod has been enabled.\nTo make this "
	"setting permanent, add \'set debuginfod enabled "
	"on\' to .gdbinit.\n"));
	debuginfod_enabled = debuginfod_on;
	}

	return true;
	}

	/* Print the result of the most recent attempted download. */

	static void
	print_outcome (user_data &data, int fd)
	{
	/* Clears the current line of progress output. */
	current_uiout->do_progress_end ();

	if (fd < 0 && fd != -ENOENT)
	gdb_printf (_ ("Download failed: %s. Continuing without %s %ps.\n"),
	safe_strerror (-fd), data.desc,
	styled_string (file_name_style.style (), data.fname));
	}

	/* See debuginfod-support.h */

	scoped_fd
	debuginfod_source_query (const unsigned char *build_id, int build_id_len,
	const char *srcpath,
	gdb::unique_xmalloc_ptr<char> *destname)
	{
	if (!debuginfod_is_enabled ())
	return scoped_fd (-ENOSYS);

	debuginfod_client *c = get_debuginfod_client ();

	if (c == nullptr)
	return scoped_fd (-ENOMEM);

	char *dname = nullptr;
	user_data data ("source file", srcpath);

	debuginfod_set_user_data (c, &data);
	gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
	if (target_supports_terminal_ours ())
	{
	term_state.emplace ();
	target_terminal::ours ();
	}

	scoped_fd fd (debuginfod_find_source (c, build_id, build_id_len, srcpath,
	&dname));
	debuginfod_set_user_data (c, nullptr);
	print_outcome (data, fd.get ());

	if (fd.get () >= 0)
	destname->reset (dname);

	return fd;
	}

	/* See debuginfod-support.h */

	scoped_fd
	debuginfod_debuginfo_query (const unsigned char *build_id, int build_id_len,
	const char *filename,
	gdb::unique_xmalloc_ptr<char> *destname)
	{
	if (!debuginfod_is_enabled ())
	return scoped_fd (-ENOSYS);

	debuginfod_client *c = get_debuginfod_client ();

	if (c == nullptr)
	return scoped_fd (-ENOMEM);

	char *dname = nullptr;
	user_data data ("separate debug info for", filename);

	debuginfod_set_user_data (c, &data);
	gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
	if (target_supports_terminal_ours ())
	{
	term_state.emplace ();
	target_terminal::ours ();
	}

	scoped_fd fd (debuginfod_find_debuginfo (c, build_id, build_id_len, &dname));
	debuginfod_set_user_data (c, nullptr);
	print_outcome (data, fd.get ());

	if (fd.get () >= 0)
	destname->reset (dname);

	return fd;
	}

	/* See debuginfod-support.h */

	scoped_fd
	debuginfod_exec_query (const unsigned char *build_id, int build_id_len,
	const char *filename,
	gdb::unique_xmalloc_ptr<char> *destname)
	{
	if (!debuginfod_is_enabled ())
	return scoped_fd (-ENOSYS);

	debuginfod_client *c = get_debuginfod_client ();

	if (c == nullptr)
	return scoped_fd (-ENOMEM);

	char *dname = nullptr;
	user_data data ("executable for", filename);

	debuginfod_set_user_data (c, &data);
	gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
	if (target_supports_terminal_ours ())
	{
	term_state.emplace ();
	target_terminal::ours ();
	}

	scoped_fd fd (debuginfod_find_executable (c, build_id, build_id_len,
	&dname));
	debuginfod_set_user_data (c, nullptr);
	print_outcome (data, fd.get ());

	if (fd.get () >= 0)
	destname->reset (dname);

	return fd;
	}
	#endif

	/* Set callback for "set debuginfod enabled". */

	static void
	set_debuginfod_enabled (const char *value)
	{
	#if defined(HAVE_LIBDEBUGINFOD)
	debuginfod_enabled = value;
	#else
	/* Disabling debuginfod when gdb is not built with it is a no-op. */
	if (value != debuginfod_off)
	error (NO_IMPL);
	#endif
	}

	/* Get callback for "set debuginfod enabled". */

	static const char *
	get_debuginfod_enabled ()
	{
	return debuginfod_enabled;
	}

	/* Show callback for "set debuginfod enabled". */

	static void
	show_debuginfod_enabled (ui_file file, int from_tty, cmd_list_element cmd,
	const char *value)
	{
	gdb_printf (file,
	_ ("Debuginfod functionality is currently set to "
	"\"%s\".\n"),
	debuginfod_enabled);
	}

	/* Set callback for "set debuginfod urls". */

	static void
	set_debuginfod_urls (const std::string &urls)
	{
	#if defined(HAVE_LIBDEBUGINFOD)
	if (setenv (DEBUGINFOD_URLS_ENV_VAR, urls.c_str (), 1) != 0)
	warning (_ ("Unable to set debuginfod URLs: %s"), safe_strerror (errno));
	#else
	error (NO_IMPL);
	#endif
	}

	/* Get callback for "set debuginfod urls". */

	static const std::string &
	get_debuginfod_urls ()
	{
	static std::string urls;
	#if defined(HAVE_LIBDEBUGINFOD)
	const char *envvar = getenv (DEBUGINFOD_URLS_ENV_VAR);

	if (envvar != nullptr)
	urls = envvar;
	else
	urls.clear ();
	#endif

	return urls;
	}

	/* Show callback for "set debuginfod urls". */

	static void
	show_debuginfod_urls (ui_file file, int from_tty, cmd_list_element cmd,
	const char *value)
	{
	if (value[0] == '\0')
	gdb_printf (file, _ ("Debuginfod URLs have not been set.\n"));
	else
	gdb_printf (file, _ ("Debuginfod URLs are currently set to:\n%s\n"),
	value);
	}

	/* Show callback for "set debuginfod verbose". */

	static void
	show_debuginfod_verbose_command (ui_file *file, int from_tty,
	cmd_list_element cmd, const char value)
	{
	gdb_printf (file, _ ("Debuginfod verbose output is set to %s.\n"), value);
	}

	/* Register debuginfod commands. */

	void _initialize_debuginfod ();

	void
	_initialize_debuginfod ()
	{
	/* set/show debuginfod */
	add_setshow_prefix_cmd ("debuginfod", class_run,
	_ ("Set debuginfod options."),
	_ ("Show debuginfod options."),
	&set_debuginfod_prefix_list,
	&show_debuginfod_prefix_list, &setlist, &showlist);

	add_setshow_enum_cmd ("enabled", class_run, debuginfod_enabled_enum,
	_ ("Set whether to use debuginfod."),
	_ ("Show whether to use debuginfod."), _ ("\
	When on, enable the use of debuginfod to download missing debug info and\n\
	source files."),
	set_debuginfod_enabled, get_debuginfod_enabled,
	show_debuginfod_enabled, &set_debuginfod_prefix_list,
	&show_debuginfod_prefix_list);

	/* set/show debuginfod urls */
	add_setshow_string_noescape_cmd ("urls", class_run, _ ("\
	Set the list of debuginfod server URLs."),
	_ ("\
	Show the list of debuginfod server URLs."),
	_ ("\
	Manage the space-separated list of debuginfod server URLs that GDB will query \
	when missing debuginfo, executables or source files.\nThe default value is \
	copied from the DEBUGINFOD_URLS environment variable."),
	set_debuginfod_urls, get_debuginfod_urls,
	show_debuginfod_urls,
	&set_debuginfod_prefix_list,
	&show_debuginfod_prefix_list);

	/* set/show debuginfod verbose */
	add_setshow_zuinteger_cmd ("verbose", class_support, &debuginfod_verbose,
	_ ("\
	Set verbosity of debuginfod output."),
	_ ("\
	Show debuginfod debugging."),
	_ ("\
	When set to a non-zero value, display verbose output for each debuginfod \
	query.\nTo disable, set to zero. Verbose output is displayed by default."),
	nullptr, show_debuginfod_verbose_command,
	&set_debuginfod_prefix_list,
	&show_debuginfod_prefix_list);
	}