gnu/dist/gettext/gettext-tools/lib/pipe.c

   1 /* Creation of subprocesses, communicating via pipes.
   2    Copyright (C) 2001-2004 Free Software Foundation, Inc.
   3    Written by Bruno Haible <haible@clisp.cons.org>, 2001.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19
  20 #ifdef HAVE_CONFIG_H
  21 # include "config.h"
  22 #endif
  23
  24 /* Specification.  */
  25 #include "pipe.h"
  26
  27 #include <errno.h>
  28 #include <fcntl.h>
  29 #include <stdlib.h>
  30 #include <signal.h>
  31
  32 #ifdef HAVE_UNISTD_H
  33 # include <unistd.h>
  34 #endif
  35
  36 #include "error.h"
  37 #include "exit.h"
  38 #include "fatal-signal.h"
  39 #include "wait-process.h"
  40 #include "gettext.h"
  41
  42 #define _(str) gettext (str)
  43
  44 #if defined _MSC_VER || defined __MINGW32__
  45
  46 /* Native Woe32 API.  */
  47 # include <process.h>
  48 # include "w32spawn.h"
  49
  50 #else
  51
  52 /* Unix API.  */
  53 # ifdef HAVE_POSIX_SPAWN
  54 #  include <spawn.h>
  55 # else
  56 #  ifdef HAVE_VFORK_H
  57 #   include <vfork.h>
  58 #  endif
  59 # endif
  60
  61 #endif
  62
  63 #ifndef HAVE_ENVIRON_DECL
  64 extern char **environ;
  65 #endif
  66
  67 #ifndef STDIN_FILENO
  68 # define STDIN_FILENO 0
  69 #endif
  70 #ifndef STDOUT_FILENO
  71 # define STDOUT_FILENO 1
  72 #endif
  73 #ifndef STDERR_FILENO
  74 # define STDERR_FILENO 2
  75 #endif
  76
  77
  78 #ifdef EINTR
  79
  80 /* EINTR handling for close().
  81    These functions can return -1/EINTR even though we don't have any
  82    signal handlers set up, namely when we get interrupted via SIGSTOP.  */
  83
  84 static inline int
  85 nonintr_close (int fd)
  86 {
  87   int retval;
  88
  89   do
  90     retval = close (fd);
  91   while (retval < 0 && errno == EINTR);
  92
  93   return retval;
  94 }
  95 #define close nonintr_close
  96
  97 static inline int
  98 nonintr_open (const char *pathname, int oflag, mode_t mode)
  99 {
 100   int retval;
 101
 102   do
 103     retval = open (pathname, oflag, mode);
 104   while (retval < 0 && errno == EINTR);
 105
 106   return retval;
 107 }
 108 #undef open /* avoid warning on VMS */
 109 #define open nonintr_open
 110
 111 #endif
 112
 113
 114 /* Open a pipe connected to a child process.
 115  *
 116  *           write       system                read
 117  *    parent  ->   fd[1]   ->   STDIN_FILENO    ->   child       if pipe_stdin
 118  *    parent  <-   fd[0]   <-   STDOUT_FILENO   <-   child       if pipe_stdout
 119  *           read        system                write
 120  *
 121  * At least one of pipe_stdin, pipe_stdout must be true.
 122  * pipe_stdin and prog_stdin together determine the child's standard input.
 123  * pipe_stdout and prog_stdout together determine the child's standard output.
 124  * If pipe_stdin is true, prog_stdin is ignored.
 125  * If pipe_stdout is true, prog_stdout is ignored.
 126  */
 127 static pid_t
 128 create_pipe (const char *progname,
 129              const char *prog_path, char **prog_argv,
 130              bool pipe_stdin, bool pipe_stdout,
 131              const char *prog_stdin, const char *prog_stdout,
 132              bool null_stderr,
 133              bool slave_process, bool exit_on_error,
 134              int fd[2])
 135 {
 136 #if defined _MSC_VER || defined __MINGW32__
 137
 138   /* Native Woe32 API.
 139      This uses _pipe(), dup2(), and spawnv().  It could also be implemented
 140      using the low-level functions CreatePipe(), DuplicateHandle(),
 141      CreateProcess() and _open_osfhandle(); see the GNU make and GNU clisp
 142      and cvs source code.  */
 143   int ifd[2];
 144   int ofd[2];
 145   int orig_stdin;
 146   int orig_stdout;
 147   int orig_stderr;
 148   int child;
 149   int nulloutfd;
 150   int stdinfd;
 151   int stdoutfd;
 152
 153   prog_argv = prepare_spawn (prog_argv);
 154
 155   if (pipe_stdout)
 156     if (_pipe (ifd, 4096, O_BINARY | O_NOINHERIT) < 0)
 157       error (EXIT_FAILURE, errno, _("cannot create pipe"));
 158   if (pipe_stdin)
 159     if (_pipe (ofd, 4096, O_BINARY | O_NOINHERIT) < 0)
 160       error (EXIT_FAILURE, errno, _("cannot create pipe"));
 161 /* Data flow diagram:
 162  *
 163  *           write        system         read
 164  *    parent  ->   ofd[1]   ->   ofd[0]   ->   child       if pipe_stdin
 165  *    parent  <-   ifd[0]   <-   ifd[1]   <-   child       if pipe_stdout
 166  *           read         system         write
 167  *
 168  */
 169
 170   /* Save standard file handles of parent process.  */
 171   if (pipe_stdin || prog_stdin != NULL)
 172     orig_stdin = dup_noinherit (STDIN_FILENO);
 173   if (pipe_stdout || prog_stdout != NULL)
 174     orig_stdout = dup_noinherit (STDOUT_FILENO);
 175   if (null_stderr)
 176     orig_stderr = dup_noinherit (STDERR_FILENO);
 177   child = -1;
 178
 179   /* Create standard file handles of child process.  */
 180   nulloutfd = -1;
 181   stdinfd = -1;
 182   stdoutfd = -1;
 183   if ((!pipe_stdin || dup2 (ofd[0], STDIN_FILENO) >= 0)
 184       && (!pipe_stdout || dup2 (ifd[1], STDOUT_FILENO) >= 0)
 185       && (!null_stderr
 186           || ((nulloutfd = open ("NUL", O_RDWR, 0)) >= 0
 187               && (nulloutfd == STDERR_FILENO
 188                   || (dup2 (nulloutfd, STDERR_FILENO) >= 0
 189                       && close (nulloutfd) >= 0))))
 190       && (pipe_stdin
 191           || prog_stdin == NULL
 192           || ((stdinfd = open (prog_stdin, O_RDONLY, 0)) >= 0
 193               && (stdinfd == STDIN_FILENO
 194                   || (dup2 (stdinfd, STDIN_FILENO) >= 0
 195                       && close (stdinfd) >= 0))))
 196       && (pipe_stdout
 197           || prog_stdout == NULL
 198           || ((stdoutfd = open (prog_stdout, O_WRONLY, 0)) >= 0
 199               && (stdoutfd == STDOUT_FILENO
 200                   || (dup2 (stdoutfd, STDOUT_FILENO) >= 0
 201                       && close (stdoutfd) >= 0)))))
 202     /* The child process doesn't inherit ifd[0], ifd[1], ofd[0], ofd[1],
 203        but it inherits all open()ed or dup2()ed file handles (which is what
 204        we want in the case of STD*_FILENO) and also orig_stdin,
 205        orig_stdout, orig_stderr (which is not explicitly wanted but
 206        harmless).  */
 207     child = spawnvp (P_NOWAIT, prog_path, prog_argv);
 208   if (stdinfd >= 0)
 209     close (stdinfd);
 210   if (stdoutfd >= 0)
 211     close (stdoutfd);
 212   if (nulloutfd >= 0)
 213     close (nulloutfd);
 214
 215   /* Restore standard file handles of parent process.  */
 216   if (null_stderr)
 217     dup2 (orig_stderr, STDERR_FILENO), close (orig_stderr);
 218   if (pipe_stdout || prog_stdout != NULL)
 219     dup2 (orig_stdout, STDOUT_FILENO), close (orig_stdout);
 220   if (pipe_stdin || prog_stdin != NULL)
 221     dup2 (orig_stdin, STDIN_FILENO), close (orig_stdin);
 222
 223   if (pipe_stdin)
 224     close (ofd[0]);
 225   if (pipe_stdout)
 226     close (ifd[1]);
 227   if (child == -1)
 228     {
 229       if (exit_on_error || !null_stderr)
 230         error (exit_on_error ? EXIT_FAILURE : 0, errno,
 231                _("%s subprocess failed"), progname);
 232       if (pipe_stdout)
 233         close (ifd[0]);
 234       if (pipe_stdin)
 235         close (ofd[1]);
 236       return -1;
 237     }
 238
 239   if (pipe_stdout)
 240     fd[0] = ifd[0];
 241   if (pipe_stdin)
 242     fd[1] = ofd[1];
 243   return child;
 244
 245 #else
 246
 247   /* Unix API.  */
 248   int ifd[2];
 249   int ofd[2];
 250 # if HAVE_POSIX_SPAWN
 251   sigset_t blocked_signals;
 252   posix_spawn_file_actions_t actions;
 253   bool actions_allocated;
 254   posix_spawnattr_t attrs;
 255   bool attrs_allocated;
 256   int err;
 257   pid_t child;
 258 # else
 259   int child;
 260 # endif
 261
 262   if (pipe_stdout)
 263     if (pipe (ifd) < 0)
 264       error (EXIT_FAILURE, errno, _("cannot create pipe"));
 265   if (pipe_stdin)
 266     if (pipe (ofd) < 0)
 267       error (EXIT_FAILURE, errno, _("cannot create pipe"));
 268 /* Data flow diagram:
 269  *
 270  *           write        system         read
 271  *    parent  ->   ofd[1]   ->   ofd[0]   ->   child       if pipe_stdin
 272  *    parent  <-   ifd[0]   <-   ifd[1]   <-   child       if pipe_stdout
 273  *           read         system         write
 274  *
 275  */
 276
 277 # if HAVE_POSIX_SPAWN
 278   if (slave_process)
 279     {
 280       sigprocmask (SIG_SETMASK, NULL, &blocked_signals);
 281       block_fatal_signals ();
 282     }
 283   actions_allocated = false;
 284   attrs_allocated = false;
 285   if ((err = posix_spawn_file_actions_init (&actions)) != 0
 286       || (actions_allocated = true,
 287           (pipe_stdin
 288            && (err = posix_spawn_file_actions_adddup2 (&actions,
 289                                                        ofd[0], STDIN_FILENO))
 290               != 0)
 291           || (pipe_stdout
 292               && (err = posix_spawn_file_actions_adddup2 (&actions,
 293                                                           ifd[1], STDOUT_FILENO))
 294                  != 0)
 295           || (pipe_stdin
 296               && (err = posix_spawn_file_actions_addclose (&actions, ofd[0]))
 297                  != 0)
 298           || (pipe_stdout
 299               && (err = posix_spawn_file_actions_addclose (&actions, ifd[1]))
 300                  != 0)
 301           || (pipe_stdin
 302               && (err = posix_spawn_file_actions_addclose (&actions, ofd[1]))
 303                  != 0)
 304           || (pipe_stdout
 305               && (err = posix_spawn_file_actions_addclose (&actions, ifd[0]))
 306                  != 0)
 307           || (null_stderr
 308               && (err = posix_spawn_file_actions_addopen (&actions,
 309                                                           STDERR_FILENO,
 310                                                           "/dev/null", O_RDWR,
 311                                                           0))
 312                  != 0)
 313           || (!pipe_stdin
 314               && prog_stdin != NULL
 315               && (err = posix_spawn_file_actions_addopen (&actions,
 316                                                           STDIN_FILENO,
 317                                                           prog_stdin, O_RDONLY,
 318                                                           0))
 319                  != 0)
 320           || (!pipe_stdout
 321               && prog_stdout != NULL
 322               && (err = posix_spawn_file_actions_addopen (&actions,
 323                                                           STDOUT_FILENO,
 324                                                           prog_stdout, O_WRONLY,
 325                                                           0))
 326                  != 0)
 327           || (slave_process
 328               && ((err = posix_spawnattr_init (&attrs)) != 0
 329                   || (attrs_allocated = true,
 330                       (err = posix_spawnattr_setsigmask (&attrs,
 331                                                          &blocked_signals))
 332                       != 0
 333                       || (err = posix_spawnattr_setflags (&attrs,
 334                                                         POSIX_SPAWN_SETSIGMASK))
 335                          != 0)))
 336           || (err = posix_spawnp (&child, prog_path, &actions,
 337                                   attrs_allocated ? &attrs : NULL, prog_argv,
 338                                   environ))
 339              != 0))
 340     {
 341       if (actions_allocated)
 342         posix_spawn_file_actions_destroy (&actions);
 343       if (attrs_allocated)
 344         posix_spawnattr_destroy (&attrs);
 345       if (slave_process)
 346         unblock_fatal_signals ();
 347       if (exit_on_error || !null_stderr)
 348         error (exit_on_error ? EXIT_FAILURE : 0, err,
 349                _("%s subprocess failed"), progname);
 350       if (pipe_stdout)
 351         {
 352           close (ifd[0]);
 353           close (ifd[1]);
 354         }
 355       if (pipe_stdin)
 356         {
 357           close (ofd[0]);
 358           close (ofd[1]);
 359         }
 360       return -1;
 361     }
 362   posix_spawn_file_actions_destroy (&actions);
 363   if (attrs_allocated)
 364     posix_spawnattr_destroy (&attrs);
 365 # else
 366   if (slave_process)
 367     block_fatal_signals ();
 368   /* Use vfork() instead of fork() for efficiency.  */
 369   if ((child = vfork ()) == 0)
 370     {
 371       /* Child process code.  */
 372       int nulloutfd;
 373       int stdinfd;
 374       int stdoutfd;
 375
 376       if ((!pipe_stdin || dup2 (ofd[0], STDIN_FILENO) >= 0)
 377           && (!pipe_stdout || dup2 (ifd[1], STDOUT_FILENO) >= 0)
 378           && (!pipe_stdin || close (ofd[0]) >= 0)
 379           && (!pipe_stdout || close (ifd[1]) >= 0)
 380           && (!pipe_stdin || close (ofd[1]) >= 0)
 381           && (!pipe_stdout || close (ifd[0]) >= 0)
 382           && (!null_stderr
 383               || ((nulloutfd = open ("/dev/null", O_RDWR, 0)) >= 0
 384                   && (nulloutfd == STDERR_FILENO
 385                       || (dup2 (nulloutfd, STDERR_FILENO) >= 0
 386                           && close (nulloutfd) >= 0))))
 387           && (pipe_stdin
 388               || prog_stdin == NULL
 389               || ((stdinfd = open (prog_stdin, O_RDONLY, 0)) >= 0
 390                   && (stdinfd == STDIN_FILENO
 391                       || (dup2 (stdinfd, STDIN_FILENO) >= 0
 392                           && close (stdinfd) >= 0))))
 393           && (pipe_stdout
 394               || prog_stdout == NULL
 395               || ((stdoutfd = open (prog_stdout, O_WRONLY, 0)) >= 0
 396                   && (stdoutfd == STDOUT_FILENO
 397                       || (dup2 (stdoutfd, STDOUT_FILENO) >= 0
 398                           && close (stdoutfd) >= 0))))
 399           && (!slave_process || (unblock_fatal_signals (), true)))
 400         execvp (prog_path, prog_argv);
 401       _exit (127);
 402     }
 403   if (child == -1)
 404     {
 405       if (slave_process)
 406         unblock_fatal_signals ();
 407       if (exit_on_error || !null_stderr)
 408         error (exit_on_error ? EXIT_FAILURE : 0, errno,
 409                _("%s subprocess failed"), progname);
 410       if (pipe_stdout)
 411         {
 412           close (ifd[0]);
 413           close (ifd[1]);
 414         }
 415       if (pipe_stdin)
 416         {
 417           close (ofd[0]);
 418           close (ofd[1]);
 419         }
 420       return -1;
 421     }
 422 # endif
 423   if (slave_process)
 424     {
 425       register_slave_subprocess (child);
 426       unblock_fatal_signals ();
 427     }
 428   if (pipe_stdin)
 429     close (ofd[0]);
 430   if (pipe_stdout)
 431     close (ifd[1]);
 432
 433   if (pipe_stdout)
 434     fd[0] = ifd[0];
 435   if (pipe_stdin)
 436     fd[1] = ofd[1];
 437   return child;
 438
 439 #endif
 440 }
 441
 442 /* Open a bidirectional pipe.
 443  *
 444  *           write       system                read
 445  *    parent  ->   fd[1]   ->   STDIN_FILENO    ->   child
 446  *    parent  <-   fd[0]   <-   STDOUT_FILENO   <-   child
 447  *           read        system                write
 448  *
 449  */
 450 pid_t
 451 create_pipe_bidi (const char *progname,
 452                   const char *prog_path, char **prog_argv,
 453                   bool null_stderr,
 454                   bool slave_process, bool exit_on_error,
 455                   int fd[2])
 456 {
 457   pid_t result = create_pipe (progname, prog_path, prog_argv,
 458                               true, true, NULL, NULL,
 459                               null_stderr, slave_process, exit_on_error,
 460                               fd);
 461   return result;
 462 }
 463
 464 /* Open a pipe for input from a child process.
 465  * The child's stdin comes from a file.
 466  *
 467  *           read        system                write
 468  *    parent  <-   fd[0]   <-   STDOUT_FILENO   <-   child
 469  *
 470  */
 471 pid_t
 472 create_pipe_in (const char *progname,
 473                 const char *prog_path, char **prog_argv,
 474                 const char *prog_stdin, bool null_stderr,
 475                 bool slave_process, bool exit_on_error,
 476                 int fd[1])
 477 {
 478   int iofd[2];
 479   pid_t result = create_pipe (progname, prog_path, prog_argv,
 480                               false, true, prog_stdin, NULL,
 481                               null_stderr, slave_process, exit_on_error,
 482                               iofd);
 483   if (result != -1)
 484     fd[0] = iofd[0];
 485   return result;
 486 }
 487
 488 /* Open a pipe for output to a child process.
 489  * The child's stdout goes to a file.
 490  *
 491  *           write       system                read
 492  *    parent  ->   fd[0]   ->   STDIN_FILENO    ->   child
 493  *
 494  */
 495 pid_t
 496 create_pipe_out (const char *progname,
 497                  const char *prog_path, char **prog_argv,
 498                  const char *prog_stdout, bool null_stderr,
 499                  bool slave_process, bool exit_on_error,
 500                  int fd[1])
 501 {
 502   int iofd[2];
 503   pid_t result = create_pipe (progname, prog_path, prog_argv,
 504                               true, false, NULL, prog_stdout,
 505                               null_stderr, slave_process, exit_on_error,
 506                               iofd);
 507   if (result != -1)
 508     fd[0] = iofd[1];
 509   return result;
 510 }