lib/execute.c - platform/external/bison - Git at Google

 /* Creation of autonomous subprocesses.
    Copyright (C) 2001-2004, 2006-2021 Free Software Foundation, Inc.
    Written by Bruno Haible <haible@clisp.cons.org>, 2001.

    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 <https://www.gnu.org/licenses/>.  */


 #include <config.h>

 /* Specification.  */
 #include "execute.h"

 #include <errno.h>
 #include <fcntl.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <signal.h>
 #include <unistd.h>

 #include <sys/types.h>
 #include <sys/wait.h>

 #include "canonicalize.h"
 #include "error.h"
 #include "fatal-signal.h"
 #include "filename.h"
 #include "findprog.h"
 #include "wait-process.h"
 #include "xalloc.h"
 #include "gettext.h"

 #define _(str) gettext (str)


 /* Choice of implementation for native Windows.
    - Define to 0 to use the posix_spawn facility (modules 'posix_spawn' and
      'posix_spawnp'), that is based on the module 'windows-spawn'.
    - Define to 1 to use the older code, that uses the module 'windows-spawn'
      directly.
    You can set this macro from a Makefile or at configure time, from the
    CPPFLAGS.  */
 #ifndef EXECUTE_IMPL_AVOID_POSIX_SPAWN
 # define EXECUTE_IMPL_AVOID_POSIX_SPAWN 0
 #endif


 #if (defined _WIN32 && !defined __CYGWIN__) && EXECUTE_IMPL_AVOID_POSIX_SPAWN

 /* Native Windows API.  */
 # if GNULIB_MSVC_NOTHROW
 #  include "msvc-nothrow.h"
 # else
 #  include <io.h>
 # endif
 # include <process.h>
 # include "windows-spawn.h"

 #else

 /* Unix API.  */
 # include <spawn.h>

 #endif


 #if defined EINTR && (defined _WIN32 && !defined __CYGWIN__) && EXECUTE_IMPL_AVOID_POSIX_SPAWN

 /* EINTR handling for close(), open().
    These functions can return -1/EINTR even though we don't have any
    signal handlers set up, namely when we get interrupted via SIGSTOP.  */

 static int
 nonintr_close (int fd)
 {
   int retval;

   do
     retval = close (fd);
   while (retval < 0 && errno == EINTR);

   return retval;
 }
 #undef close /* avoid warning related to gnulib module unistd */
 #define close nonintr_close

 static int
 nonintr_open (const char *pathname, int oflag, mode_t mode)
 {
   int retval;

   do
     retval = open (pathname, oflag, mode);
   while (retval < 0 && errno == EINTR);

   return retval;
 }
 #undef open /* avoid warning on VMS */
 #define open nonintr_open

 #endif


 int
 execute (const char *progname,
          const char *prog_path, const char * const *prog_argv,
          const char *directory,
          bool ignore_sigpipe,
          bool null_stdin, bool null_stdout, bool null_stderr,
          bool slave_process, bool exit_on_error,
          int *termsigp)
 {
   int saved_errno;
   char *prog_path_to_free = NULL;

   if (directory != NULL)
     {
       /* If a change of directory is requested, make sure PROG_PATH is absolute
          before we do so.  This is needed because
            - posix_spawn and posix_spawnp are required to resolve a relative
              PROG_PATH *after* changing the directory.  See
              <https://www.austingroupbugs.net/view.php?id=1208>:
                "if this pathname does not start with a <slash> it shall be
                 interpreted relative to the working directory of the child
                 process _after_ all file_actions have been performed."
              But this would be a surprising application behaviour, possibly
              even security relevant.
            - For the Windows CreateProcess() function, it is unspecified whether
              a relative file name is interpreted to the parent's current
              directory or to the specified directory.  See
              <https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessa>  */
       if (! IS_ABSOLUTE_FILE_NAME (prog_path))
         {
           const char *resolved_prog =
             find_in_given_path (prog_path, getenv ("PATH"), NULL, false);
           if (resolved_prog == NULL)
             goto fail_with_errno;
           if (resolved_prog != prog_path)
             prog_path_to_free = (char *) resolved_prog;
           prog_path = resolved_prog;

           if (! IS_ABSOLUTE_FILE_NAME (prog_path))
             {
               char *absolute_prog =
                 canonicalize_filename_mode (prog_path,
                                             CAN_MISSING | CAN_NOLINKS);
               if (absolute_prog == NULL)
                 {
                   free (prog_path_to_free);
                   goto fail_with_errno;
                 }
               free (prog_path_to_free);
               prog_path_to_free = absolute_prog;
               prog_path = absolute_prog;

               if (! IS_ABSOLUTE_FILE_NAME (prog_path))
                 abort ();
             }
         }
     }

 #if (defined _WIN32 && !defined __CYGWIN__) && EXECUTE_IMPL_AVOID_POSIX_SPAWN

   /* Native Windows API.  */

   char *argv_mem_to_free;

   const char **argv = prepare_spawn (prog_argv, &argv_mem_to_free);
   if (argv == NULL)
     xalloc_die ();

   int exitcode = -1;

   /* Create standard file handles of child process.  */
   int nullinfd = -1;
   int nulloutfd = -1;
   if ((!null_stdin
        || (nullinfd = open ("NUL", O_RDONLY, 0)) >= 0)
       && (!(null_stdout || null_stderr)
           || (nulloutfd = open ("NUL", O_RDWR, 0)) >= 0))
     /* Pass the environment explicitly.  This is needed if the program has
        modified the environment using putenv() or [un]setenv().  On Windows,
        processes have two environments, one in the "environment block" of the
        process and managed through SetEnvironmentVariable(), and one inside the
        process, in the location retrieved by the 'environ' macro.  If we were
        to pass NULL, the child process would inherit a copy of the environment
        block - ignoring the effects of putenv() and [un]setenv().  */
     {
       HANDLE stdin_handle =
         (HANDLE) _get_osfhandle (null_stdin ? nullinfd : STDIN_FILENO);
       HANDLE stdout_handle =
         (HANDLE) _get_osfhandle (null_stdout ? nulloutfd : STDOUT_FILENO);
       HANDLE stderr_handle =
         (HANDLE) _get_osfhandle (null_stderr ? nulloutfd : STDERR_FILENO);

       exitcode = spawnpvech (P_WAIT, prog_path, argv + 1,
                              (const char * const *) environ, directory,
                              stdin_handle, stdout_handle, stderr_handle);
 # if 0 /* Executing arbitrary files as shell scripts is unsecure.  */
       if (exitcode == -1 && errno == ENOEXEC)
         {
           /* prog is not a native executable.  Try to execute it as a
              shell script.  Note that prepare_spawn() has already prepended
              a hidden element "sh.exe" to argv.  */
           argv[1] = prog_path;
           exitcode = spawnpvech (P_WAIT, argv[0], argv,
                                  (const char * const *) environ, directory,
                                  stdin_handle, stdout_handle, stderr_handle);
         }
 # endif
     }
   if (exitcode == -1)
     saved_errno = errno;
   if (nulloutfd >= 0)
     close (nulloutfd);
   if (nullinfd >= 0)
     close (nullinfd);
   free (argv);
   free (argv_mem_to_free);
   free (prog_path_to_free);

   /* Treat failure and signalled child processes like wait_subprocess()
      does.  */
   if (termsigp != NULL)
     *termsigp = 0;

   if (exitcode == -1)
     goto fail_with_saved_errno;

   if (WIFSIGNALED (exitcode))
     {
       if (termsigp != NULL)
         *termsigp = WTERMSIG (exitcode);
       saved_errno = 0;
       goto fail_with_saved_errno;
     }

   return exitcode;

 #else

   /* Unix API.  */
   /* Note about 127: Some errors during posix_spawnp() cause the function
      posix_spawnp() to return an error code; some other errors cause the
      subprocess to exit with return code 127.  It is implementation
      dependent which error is reported which way.  We treat both cases as
      equivalent.  */
   sigset_t blocked_signals;
   posix_spawn_file_actions_t actions;
   bool actions_allocated;
   posix_spawnattr_t attrs;
   bool attrs_allocated;
   int err;
   pid_t child;

   if (slave_process)
     {
       sigprocmask (SIG_SETMASK, NULL, &blocked_signals);
       block_fatal_signals ();
     }
   actions_allocated = false;
   attrs_allocated = false;
   if ((err = posix_spawn_file_actions_init (&actions)) != 0
       || (actions_allocated = true,
           (null_stdin
             && (err = posix_spawn_file_actions_addopen (&actions,
                                                         STDIN_FILENO,
                                                         "/dev/null", O_RDONLY,
                                                         0))
                != 0)
           || (null_stdout
               && (err = posix_spawn_file_actions_addopen (&actions,
                                                           STDOUT_FILENO,
                                                           "/dev/null", O_RDWR,
                                                           0))
                  != 0)
           || (null_stderr
               && (err = posix_spawn_file_actions_addopen (&actions,
                                                           STDERR_FILENO,
                                                           "/dev/null", O_RDWR,
                                                           0))
                  != 0)
           || (directory != NULL
               && (err = posix_spawn_file_actions_addchdir (&actions,
                                                            directory)))
 # if !(defined _WIN32 && !defined __CYGWIN__)
           || (slave_process
               && ((err = posix_spawnattr_init (&attrs)) != 0
                   || (attrs_allocated = true,
                       (err = posix_spawnattr_setsigmask (&attrs,
                                                          &blocked_signals))
                       != 0
                       || (err = posix_spawnattr_setflags (&attrs,
                                                         POSIX_SPAWN_SETSIGMASK))
                          != 0)))
 # endif
           || (err = (directory != NULL
                      ? posix_spawn (&child, prog_path, &actions,
                                     attrs_allocated ? &attrs : NULL,
                                     (char * const *) prog_argv, environ)
                      : posix_spawnp (&child, prog_path, &actions,
                                      attrs_allocated ? &attrs : NULL,
                                      (char * const *) prog_argv, environ)))
              != 0))
     {
       if (actions_allocated)
         posix_spawn_file_actions_destroy (&actions);
       if (attrs_allocated)
         posix_spawnattr_destroy (&attrs);
       if (slave_process)
         unblock_fatal_signals ();
       free (prog_path_to_free);
       if (termsigp != NULL)
         *termsigp = 0;
       saved_errno = err;
       goto fail_with_saved_errno;
     }
   posix_spawn_file_actions_destroy (&actions);
   if (attrs_allocated)
     posix_spawnattr_destroy (&attrs);
   if (slave_process)
     {
       register_slave_subprocess (child);
       unblock_fatal_signals ();
     }
   free (prog_path_to_free);

   return wait_subprocess (child, progname, ignore_sigpipe, null_stderr,
                           slave_process, exit_on_error, termsigp);

 #endif

  fail_with_errno:
   saved_errno = errno;
  fail_with_saved_errno:
   if (exit_on_error || !null_stderr)
     error (exit_on_error ? EXIT_FAILURE : 0, saved_errno,
            _("%s subprocess failed"), progname);
   return 127;
 }
	/* Creation of autonomous subprocesses.
	Copyright (C) 2001-2004, 2006-2021 Free Software Foundation, Inc.
	Written by Bruno Haible <haible@clisp.cons.org>, 2001.

	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 <https://www.gnu.org/licenses/>. */


	#include <config.h>

	/* Specification. */
	#include "execute.h"

	#include <errno.h>
	#include <fcntl.h>
	#include <stdbool.h>
	#include <stdlib.h>
	#include <signal.h>
	#include <unistd.h>

	#include <sys/types.h>
	#include <sys/wait.h>

	#include "canonicalize.h"
	#include "error.h"
	#include "fatal-signal.h"
	#include "filename.h"
	#include "findprog.h"
	#include "wait-process.h"
	#include "xalloc.h"
	#include "gettext.h"

	#define _(str) gettext (str)


	/* Choice of implementation for native Windows.
	- Define to 0 to use the posix_spawn facility (modules 'posix_spawn' and
	'posix_spawnp'), that is based on the module 'windows-spawn'.
	- Define to 1 to use the older code, that uses the module 'windows-spawn'
	directly.
	You can set this macro from a Makefile or at configure time, from the
	CPPFLAGS. */
	#ifndef EXECUTE_IMPL_AVOID_POSIX_SPAWN
	# define EXECUTE_IMPL_AVOID_POSIX_SPAWN 0
	#endif


	#if (defined _WIN32 && !defined __CYGWIN__) && EXECUTE_IMPL_AVOID_POSIX_SPAWN

	/* Native Windows API. */
	# if GNULIB_MSVC_NOTHROW
	# include "msvc-nothrow.h"
	# else
	# include <io.h>
	# endif
	# include <process.h>
	# include "windows-spawn.h"

	#else

	/* Unix API. */
	# include <spawn.h>

	#endif


	#if defined EINTR && (defined _WIN32 && !defined __CYGWIN__) && EXECUTE_IMPL_AVOID_POSIX_SPAWN

	/* EINTR handling for close(), open().
	These functions can return -1/EINTR even though we don't have any
	signal handlers set up, namely when we get interrupted via SIGSTOP. */

	static int
	nonintr_close (int fd)
	{
	int retval;

	do
	retval = close (fd);
	while (retval < 0 && errno == EINTR);

	return retval;
	}
	#undef close /* avoid warning related to gnulib module unistd */
	#define close nonintr_close

	static int
	nonintr_open (const char *pathname, int oflag, mode_t mode)
	{
	int retval;

	do
	retval = open (pathname, oflag, mode);
	while (retval < 0 && errno == EINTR);

	return retval;
	}
	#undef open /* avoid warning on VMS */
	#define open nonintr_open

	#endif


	int
	execute (const char *progname,
	const char prog_path, const char const *prog_argv,
	const char *directory,
	bool ignore_sigpipe,
	bool null_stdin, bool null_stdout, bool null_stderr,
	bool slave_process, bool exit_on_error,
	int *termsigp)
	{
	int saved_errno;
	char *prog_path_to_free = NULL;

	if (directory != NULL)
	{
	/* If a change of directory is requested, make sure PROG_PATH is absolute
	before we do so. This is needed because
	- posix_spawn and posix_spawnp are required to resolve a relative
	PROG_PATH after changing the directory. See
	<https://www.austingroupbugs.net/view.php?id=1208>:
	"if this pathname does not start with a <slash> it shall be
	interpreted relative to the working directory of the child
	process _after_ all file_actions have been performed."
	But this would be a surprising application behaviour, possibly
	even security relevant.
	- For the Windows CreateProcess() function, it is unspecified whether
	a relative file name is interpreted to the parent's current
	directory or to the specified directory. See
	<https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessa> */
	if (! IS_ABSOLUTE_FILE_NAME (prog_path))
	{
	const char *resolved_prog =
	find_in_given_path (prog_path, getenv ("PATH"), NULL, false);
	if (resolved_prog == NULL)
	goto fail_with_errno;
	if (resolved_prog != prog_path)
	prog_path_to_free = (char *) resolved_prog;
	prog_path = resolved_prog;

	if (! IS_ABSOLUTE_FILE_NAME (prog_path))
	{
	char *absolute_prog =
	canonicalize_filename_mode (prog_path,
	CAN_MISSING \| CAN_NOLINKS);
	if (absolute_prog == NULL)
	{
	free (prog_path_to_free);
	goto fail_with_errno;
	}
	free (prog_path_to_free);
	prog_path_to_free = absolute_prog;
	prog_path = absolute_prog;

	if (! IS_ABSOLUTE_FILE_NAME (prog_path))
	abort ();
	}
	}
	}

	#if (defined _WIN32 && !defined __CYGWIN__) && EXECUTE_IMPL_AVOID_POSIX_SPAWN

	/* Native Windows API. */

	char *argv_mem_to_free;

	const char **argv = prepare_spawn (prog_argv, &argv_mem_to_free);
	if (argv == NULL)
	xalloc_die ();

	int exitcode = -1;

	/* Create standard file handles of child process. */
	int nullinfd = -1;
	int nulloutfd = -1;
	if ((!null_stdin
	\|\| (nullinfd = open ("NUL", O_RDONLY, 0)) >= 0)
	&& (!(null_stdout \|\| null_stderr)
	\|\| (nulloutfd = open ("NUL", O_RDWR, 0)) >= 0))
	/* Pass the environment explicitly. This is needed if the program has
	modified the environment using putenv() or [un]setenv(). On Windows,
	processes have two environments, one in the "environment block" of the
	process and managed through SetEnvironmentVariable(), and one inside the
	process, in the location retrieved by the 'environ' macro. If we were
	to pass NULL, the child process would inherit a copy of the environment
	block - ignoring the effects of putenv() and [un]setenv(). */
	{
	HANDLE stdin_handle =
	(HANDLE) _get_osfhandle (null_stdin ? nullinfd : STDIN_FILENO);
	HANDLE stdout_handle =
	(HANDLE) _get_osfhandle (null_stdout ? nulloutfd : STDOUT_FILENO);
	HANDLE stderr_handle =
	(HANDLE) _get_osfhandle (null_stderr ? nulloutfd : STDERR_FILENO);

	exitcode = spawnpvech (P_WAIT, prog_path, argv + 1,
	(const char * const *) environ, directory,
	stdin_handle, stdout_handle, stderr_handle);
	# if 0 /* Executing arbitrary files as shell scripts is unsecure. */
	if (exitcode == -1 && errno == ENOEXEC)
	{
	/* prog is not a native executable. Try to execute it as a
	shell script. Note that prepare_spawn() has already prepended
	a hidden element "sh.exe" to argv. */
	argv[1] = prog_path;
	exitcode = spawnpvech (P_WAIT, argv[0], argv,
	(const char * const *) environ, directory,
	stdin_handle, stdout_handle, stderr_handle);
	}
	# endif
	}
	if (exitcode == -1)
	saved_errno = errno;
	if (nulloutfd >= 0)
	close (nulloutfd);
	if (nullinfd >= 0)
	close (nullinfd);
	free (argv);
	free (argv_mem_to_free);
	free (prog_path_to_free);

	/* Treat failure and signalled child processes like wait_subprocess()
	does. */
	if (termsigp != NULL)
	*termsigp = 0;

	if (exitcode == -1)
	goto fail_with_saved_errno;

	if (WIFSIGNALED (exitcode))
	{
	if (termsigp != NULL)
	*termsigp = WTERMSIG (exitcode);
	saved_errno = 0;
	goto fail_with_saved_errno;
	}

	return exitcode;

	#else

	/* Unix API. */
	/* Note about 127: Some errors during posix_spawnp() cause the function
	posix_spawnp() to return an error code; some other errors cause the
	subprocess to exit with return code 127. It is implementation
	dependent which error is reported which way. We treat both cases as
	equivalent. */
	sigset_t blocked_signals;
	posix_spawn_file_actions_t actions;
	bool actions_allocated;
	posix_spawnattr_t attrs;
	bool attrs_allocated;
	int err;
	pid_t child;

	if (slave_process)
	{
	sigprocmask (SIG_SETMASK, NULL, &blocked_signals);
	block_fatal_signals ();
	}
	actions_allocated = false;
	attrs_allocated = false;
	if ((err = posix_spawn_file_actions_init (&actions)) != 0
	\|\| (actions_allocated = true,
	(null_stdin
	&& (err = posix_spawn_file_actions_addopen (&actions,
	STDIN_FILENO,
	"/dev/null", O_RDONLY,
	0))
	!= 0)
	\|\| (null_stdout
	&& (err = posix_spawn_file_actions_addopen (&actions,
	STDOUT_FILENO,
	"/dev/null", O_RDWR,
	0))
	!= 0)
	\|\| (null_stderr
	&& (err = posix_spawn_file_actions_addopen (&actions,
	STDERR_FILENO,
	"/dev/null", O_RDWR,
	0))
	!= 0)
	\|\| (directory != NULL
	&& (err = posix_spawn_file_actions_addchdir (&actions,
	directory)))
	# if !(defined _WIN32 && !defined __CYGWIN__)
	\|\| (slave_process
	&& ((err = posix_spawnattr_init (&attrs)) != 0
	\|\| (attrs_allocated = true,
	(err = posix_spawnattr_setsigmask (&attrs,
	&blocked_signals))
	!= 0
	\|\| (err = posix_spawnattr_setflags (&attrs,
	POSIX_SPAWN_SETSIGMASK))
	!= 0)))
	# endif
	\|\| (err = (directory != NULL
	? posix_spawn (&child, prog_path, &actions,
	attrs_allocated ? &attrs : NULL,
	(char * const *) prog_argv, environ)
	: posix_spawnp (&child, prog_path, &actions,
	attrs_allocated ? &attrs : NULL,
	(char * const *) prog_argv, environ)))
	!= 0))
	{
	if (actions_allocated)
	posix_spawn_file_actions_destroy (&actions);
	if (attrs_allocated)
	posix_spawnattr_destroy (&attrs);
	if (slave_process)
	unblock_fatal_signals ();
	free (prog_path_to_free);
	if (termsigp != NULL)
	*termsigp = 0;
	saved_errno = err;
	goto fail_with_saved_errno;
	}
	posix_spawn_file_actions_destroy (&actions);
	if (attrs_allocated)
	posix_spawnattr_destroy (&attrs);
	if (slave_process)
	{
	register_slave_subprocess (child);
	unblock_fatal_signals ();
	}
	free (prog_path_to_free);

	return wait_subprocess (child, progname, ignore_sigpipe, null_stderr,
	slave_process, exit_on_error, termsigp);

	#endif

	fail_with_errno:
	saved_errno = errno;
	fail_with_saved_errno:
	if (exit_on_error \|\| !null_stderr)
	error (exit_on_error ? EXIT_FAILURE : 0, saved_errno,
	_("%s subprocess failed"), progname);
	return 127;
	}