gspawn.c 52.9 KB
Newer Older
Havoc Pennington's avatar
Havoc Pennington committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
/* gspawn.c - Process launching
 *
 *  Copyright 2000 Red Hat, Inc.
 *  g_execvpe implementation based on GNU libc execvp:
 *   Copyright 1991, 92, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
 *
 * GLib is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * GLib 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with GLib; see the file COPYING.LIB.  If not, write
 * to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

23
#include "config.h"
Owen Taylor's avatar
Owen Taylor committed
24

Havoc Pennington's avatar
Havoc Pennington committed
25 26 27 28 29 30 31 32
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
33
#include <stdlib.h>   /* for fdwalk */
34
#include <dirent.h>
Havoc Pennington's avatar
Havoc Pennington committed
35

36 37 38 39
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif /* HAVE_SYS_SELECT_H */

40 41 42 43
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif /* HAVE_SYS_RESOURCE_H */

44 45
#include "gspawn.h"

46
#include "genviron.h"
47
#include "gmem.h"
48
#include "gshell.h"
49
#include "gstring.h"
50
#include "gstrfuncs.h"
51 52
#include "gtestutils.h"
#include "gutils.h"
Owen Taylor's avatar
Owen Taylor committed
53
#include "glibintl.h"
Havoc Pennington's avatar
Havoc Pennington committed
54

55 56 57 58 59 60 61 62 63

/**
 * SECTION:spawn
 * @Short_description: process launching
 * @Title: Spawning Processes
 */



Havoc Pennington's avatar
Havoc Pennington committed
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
static gint g_execute (const gchar  *file,
                       gchar **argv,
                       gchar **envp,
                       gboolean search_path);

static gboolean make_pipe            (gint                  p[2],
                                      GError              **error);
static gboolean fork_exec_with_pipes (gboolean              intermediate_child,
                                      const gchar          *working_directory,
                                      gchar               **argv,
                                      gchar               **envp,
                                      gboolean              close_descriptors,
                                      gboolean              search_path,
                                      gboolean              stdout_to_null,
                                      gboolean              stderr_to_null,
                                      gboolean              child_inherits_stdin,
80
                                      gboolean              file_and_argv_zero,
Havoc Pennington's avatar
Havoc Pennington committed
81 82
                                      GSpawnChildSetupFunc  child_setup,
                                      gpointer              user_data,
Owen Taylor's avatar
Owen Taylor committed
83
                                      GPid                 *child_pid,
Havoc Pennington's avatar
Havoc Pennington committed
84 85 86 87 88 89 90 91
                                      gint                 *standard_input,
                                      gint                 *standard_output,
                                      gint                 *standard_error,
                                      GError              **error);

GQuark
g_spawn_error_quark (void)
{
92
  return g_quark_from_static_string ("g-exec-error-quark");
Havoc Pennington's avatar
Havoc Pennington committed
93 94 95 96
}

/**
 * g_spawn_async:
97 98 99
 * @working_directory: (allow-none): child's current working directory, or %NULL to inherit parent's
 * @argv: (array zero-terminated=1): child's argument vector
 * @envp: (array zero-terminated=1) (allow-none): child's environment, or %NULL to inherit parent's
Havoc Pennington's avatar
Havoc Pennington committed
100
 * @flags: flags from #GSpawnFlags
101 102 103
 * @child_setup: (scope async) (allow-none): function to run in the child just before exec()
 * @user_data: (closure): user data for @child_setup
 * @child_pid: (out) (allow-none): return location for child process reference, or %NULL
Havoc Pennington's avatar
Havoc Pennington committed
104 105 106 107
 * @error: return location for error
 * 
 * See g_spawn_async_with_pipes() for a full description; this function
 * simply calls the g_spawn_async_with_pipes() without any pipes.
108 109 110
 *
 * You should call g_spawn_close_pid() on the returned child process
 * reference when you don't need it any more.
Havoc Pennington's avatar
Havoc Pennington committed
111
 * 
112 113 114
 * <note><para>
 * If you are writing a GTK+ application, and the program you 
 * are spawning is a graphical application, too, then you may
Stef Walter's avatar
Stef Walter committed
115
 * want to use gdk_spawn_on_screen() instead to ensure that
116
 * the spawned program opens its windows on the right screen.
117 118
 * </para></note>
 *
119 120 121 122 123
 * <note><para> Note that the returned @child_pid on Windows is a
 * handle to the child process and not its identifier. Process handles
 * and process identifiers are different concepts on Windows.
 * </para></note>
 *
Matthias Clasen's avatar
Matthias Clasen committed
124
 * Return value: %TRUE on success, %FALSE if error is set
Havoc Pennington's avatar
Havoc Pennington committed
125 126 127 128 129 130 131 132
 **/
gboolean
g_spawn_async (const gchar          *working_directory,
               gchar               **argv,
               gchar               **envp,
               GSpawnFlags           flags,
               GSpawnChildSetupFunc  child_setup,
               gpointer              user_data,
Owen Taylor's avatar
Owen Taylor committed
133
               GPid                 *child_pid,
Havoc Pennington's avatar
Havoc Pennington committed
134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156
               GError              **error)
{
  g_return_val_if_fail (argv != NULL, FALSE);
  
  return g_spawn_async_with_pipes (working_directory,
                                   argv, envp,
                                   flags,
                                   child_setup,
                                   user_data,
                                   child_pid,
                                   NULL, NULL, NULL,
                                   error);
}

/* Avoids a danger in threaded situations (calling close()
 * on a file descriptor twice, and another thread has
 * re-opened it since the first close)
 */
static gint
close_and_invalidate (gint *fd)
{
  gint ret;

157 158 159 160
  if (*fd < 0)
    return -1;
  else
    {
161
    again:
162
      ret = close (*fd);
163 164
      if (ret == -1 && errno == EINTR)
	goto again;
165 166
      *fd = -1;
    }
Havoc Pennington's avatar
Havoc Pennington committed
167 168 169 170

  return ret;
}

Matthias Clasen's avatar
Matthias Clasen committed
171
/* Some versions of OS X define READ_OK in public headers */
172 173
#undef READ_OK

Havoc Pennington's avatar
Havoc Pennington committed
174 175 176 177 178 179 180 181 182 183 184 185
typedef enum
{
  READ_FAILED = 0, /* FALSE */
  READ_OK,
  READ_EOF
} ReadResult;

static ReadResult
read_data (GString *str,
           gint     fd,
           GError **error)
{
186 187
  gssize bytes;
  gchar buf[4096];
Havoc Pennington's avatar
Havoc Pennington committed
188 189

 again:
190
  bytes = read (fd, buf, 4096);
Havoc Pennington's avatar
Havoc Pennington committed
191 192 193 194 195 196 197 198

  if (bytes == 0)
    return READ_EOF;
  else if (bytes > 0)
    {
      g_string_append_len (str, buf, bytes);
      return READ_OK;
    }
199
  else if (errno == EINTR)
Havoc Pennington's avatar
Havoc Pennington committed
200
    goto again;
201
  else
Havoc Pennington's avatar
Havoc Pennington committed
202
    {
Christian Persch's avatar
Christian Persch committed
203 204
      int errsv = errno;

Havoc Pennington's avatar
Havoc Pennington committed
205 206 207 208
      g_set_error (error,
                   G_SPAWN_ERROR,
                   G_SPAWN_ERROR_READ,
                   _("Failed to read data from child process (%s)"),
Christian Persch's avatar
Christian Persch committed
209
                   g_strerror (errsv));
210

Havoc Pennington's avatar
Havoc Pennington committed
211 212 213 214 215 216
      return READ_FAILED;
    }
}

/**
 * g_spawn_sync:
217 218 219 220 221 222
 * @working_directory: (allow-none): child's current working directory, or %NULL to inherit parent's
 * @argv: (array zero-terminated=1): child's argument vector
 * @envp: (array zero-terminated=1) (allow-none): child's environment, or %NULL to inherit parent's
 * @flags: flags from #GSpawnFlags
 * @child_setup: (scope async) (allow-none): function to run in the child just before exec()
 * @user_data: (closure): user data for @child_setup
Colin Walters's avatar
Colin Walters committed
223 224
 * @standard_output: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child output, or %NULL
 * @standard_error: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child error messages, or %NULL
225
 * @exit_status: (out) (allow-none): return location for child exit status, as returned by waitpid(), or %NULL
226
 * @error: return location for error, or %NULL
Havoc Pennington's avatar
Havoc Pennington committed
227 228 229
 *
 * Executes a child synchronously (waits for the child to exit before returning).
 * All output from the child is stored in @standard_output and @standard_error,
230 231 232 233 234 235 236 237 238 239 240
 * if those parameters are non-%NULL. Note that you must set the  
 * %G_SPAWN_STDOUT_TO_DEV_NULL and %G_SPAWN_STDERR_TO_DEV_NULL flags when
 * passing %NULL for @standard_output and @standard_error.
 * If @exit_status is non-%NULL, the exit status of the child is stored
 * there as it would be returned by waitpid(); standard UNIX macros such 
 * as WIFEXITED() and WEXITSTATUS() must be used to evaluate the exit status.
 * Note that this function call waitpid() even if @exit_status is %NULL, and
 * does not accept the %G_SPAWN_DO_NOT_REAP_CHILD flag.
 * If an error occurs, no data is returned in @standard_output, 
 * @standard_error, or @exit_status. 
 *
241 242 243
 * This function calls g_spawn_async_with_pipes() internally; see that
 * function for full details on the other parameters and details on
 * how these functions work on Windows.
Havoc Pennington's avatar
Havoc Pennington committed
244
 * 
Matthias Clasen's avatar
Matthias Clasen committed
245
 * Return value: %TRUE on success, %FALSE if an error was set.
Havoc Pennington's avatar
Havoc Pennington committed
246 247 248 249 250 251 252 253 254 255 256 257 258 259 260
 **/
gboolean
g_spawn_sync (const gchar          *working_directory,
              gchar               **argv,
              gchar               **envp,
              GSpawnFlags           flags,
              GSpawnChildSetupFunc  child_setup,
              gpointer              user_data,
              gchar               **standard_output,
              gchar               **standard_error,
              gint                 *exit_status,
              GError              **error)     
{
  gint outpipe = -1;
  gint errpipe = -1;
Owen Taylor's avatar
Owen Taylor committed
261
  GPid pid;
Havoc Pennington's avatar
Havoc Pennington committed
262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293
  fd_set fds;
  gint ret;
  GString *outstr = NULL;
  GString *errstr = NULL;
  gboolean failed;
  gint status;
  
  g_return_val_if_fail (argv != NULL, FALSE);
  g_return_val_if_fail (!(flags & G_SPAWN_DO_NOT_REAP_CHILD), FALSE);
  g_return_val_if_fail (standard_output == NULL ||
                        !(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE);
  g_return_val_if_fail (standard_error == NULL ||
                        !(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE);
  
  /* Just to ensure segfaults if callers try to use
   * these when an error is reported.
   */
  if (standard_output)
    *standard_output = NULL;

  if (standard_error)
    *standard_error = NULL;
  
  if (!fork_exec_with_pipes (FALSE,
                             working_directory,
                             argv,
                             envp,
                             !(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
                             (flags & G_SPAWN_SEARCH_PATH) != 0,
                             (flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0,
                             (flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0,
                             (flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0,
294
                             (flags & G_SPAWN_FILE_AND_ARGV_ZERO) != 0,
Havoc Pennington's avatar
Havoc Pennington committed
295 296 297 298 299 300 301 302 303 304 305 306 307 308 309
                             child_setup,
                             user_data,
                             &pid,
                             NULL,
                             standard_output ? &outpipe : NULL,
                             standard_error ? &errpipe : NULL,
                             error))
    return FALSE;

  /* Read data from child. */
  
  failed = FALSE;

  if (outpipe >= 0)
    {
310
      outstr = g_string_new (NULL);
Havoc Pennington's avatar
Havoc Pennington committed
311 312 313 314
    }
      
  if (errpipe >= 0)
    {
315
      errstr = g_string_new (NULL);
Havoc Pennington's avatar
Havoc Pennington committed
316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335
    }

  /* Read data until we get EOF on both pipes. */
  while (!failed &&
         (outpipe >= 0 ||
          errpipe >= 0))
    {
      ret = 0;
          
      FD_ZERO (&fds);
      if (outpipe >= 0)
        FD_SET (outpipe, &fds);
      if (errpipe >= 0)
        FD_SET (errpipe, &fds);
          
      ret = select (MAX (outpipe, errpipe) + 1,
                    &fds,
                    NULL, NULL,
                    NULL /* no timeout */);

336
      if (ret < 0)
Havoc Pennington's avatar
Havoc Pennington committed
337
        {
Christian Persch's avatar
Christian Persch committed
338 339
          int errsv = errno;

340 341 342
	  if (errno == EINTR)
	    continue;

Havoc Pennington's avatar
Havoc Pennington committed
343 344 345 346 347 348
          failed = TRUE;

          g_set_error (error,
                       G_SPAWN_ERROR,
                       G_SPAWN_ERROR_READ,
                       _("Unexpected error in select() reading data from a child process (%s)"),
Christian Persch's avatar
Christian Persch committed
349
                       g_strerror (errsv));
Havoc Pennington's avatar
Havoc Pennington committed
350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425
              
          break;
        }

      if (outpipe >= 0 && FD_ISSET (outpipe, &fds))
        {
          switch (read_data (outstr, outpipe, error))
            {
            case READ_FAILED:
              failed = TRUE;
              break;
            case READ_EOF:
              close_and_invalidate (&outpipe);
              outpipe = -1;
              break;
            default:
              break;
            }

          if (failed)
            break;
        }

      if (errpipe >= 0 && FD_ISSET (errpipe, &fds))
        {
          switch (read_data (errstr, errpipe, error))
            {
            case READ_FAILED:
              failed = TRUE;
              break;
            case READ_EOF:
              close_and_invalidate (&errpipe);
              errpipe = -1;
              break;
            default:
              break;
            }

          if (failed)
            break;
        }
    }

  /* These should only be open still if we had an error.  */
  
  if (outpipe >= 0)
    close_and_invalidate (&outpipe);
  if (errpipe >= 0)
    close_and_invalidate (&errpipe);
  
  /* Wait for child to exit, even if we have
   * an error pending.
   */
 again:
      
  ret = waitpid (pid, &status, 0);

  if (ret < 0)
    {
      if (errno == EINTR)
        goto again;
      else if (errno == ECHILD)
        {
          if (exit_status)
            {
              g_warning ("In call to g_spawn_sync(), exit status of a child process was requested but SIGCHLD action was set to SIG_IGN and ECHILD was received by waitpid(), so exit status can't be returned. This is a bug in the program calling g_spawn_sync(); either don't request the exit status, or don't set the SIGCHLD action.");
            }
          else
            {
              /* We don't need the exit status. */
            }
        }
      else
        {
          if (!failed) /* avoid error pileups */
            {
Christian Persch's avatar
Christian Persch committed
426 427
              int errsv = errno;

Havoc Pennington's avatar
Havoc Pennington committed
428 429 430 431 432 433
              failed = TRUE;
                  
              g_set_error (error,
                           G_SPAWN_ERROR,
                           G_SPAWN_ERROR_READ,
                           _("Unexpected error in waitpid() (%s)"),
Christian Persch's avatar
Christian Persch committed
434
                           g_strerror (errsv));
Havoc Pennington's avatar
Havoc Pennington committed
435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464
            }
        }
    }
  
  if (failed)
    {
      if (outstr)
        g_string_free (outstr, TRUE);
      if (errstr)
        g_string_free (errstr, TRUE);

      return FALSE;
    }
  else
    {
      if (exit_status)
        *exit_status = status;
      
      if (standard_output)        
        *standard_output = g_string_free (outstr, FALSE);

      if (standard_error)
        *standard_error = g_string_free (errstr, FALSE);

      return TRUE;
    }
}

/**
 * g_spawn_async_with_pipes:
465 466 467
 * @working_directory: (allow-none): child's current working directory, or %NULL to inherit parent's, in the GLib file name encoding
 * @argv: (array zero-terminated=1): child's argument vector, in the GLib file name encoding
 * @envp: (array zero-terminated=1) (allow-none): child's environment, or %NULL to inherit parent's, in the GLib file name encoding
Havoc Pennington's avatar
Havoc Pennington committed
468
 * @flags: flags from #GSpawnFlags
469 470 471 472 473 474
 * @child_setup: (scope async) (allow-none): function to run in the child just before exec()
 * @user_data: (closure): user data for @child_setup
 * @child_pid: (out) (allow-none): return location for child process ID, or %NULL
 * @standard_input: (out) (allow-none): return location for file descriptor to write to child's stdin, or %NULL
 * @standard_output: (out) (allow-none): return location for file descriptor to read child's stdout, or %NULL
 * @standard_error: (out) (allow-none): return location for file descriptor to read child's stderr, or %NULL
Havoc Pennington's avatar
Havoc Pennington committed
475 476 477 478 479
 * @error: return location for error
 *
 * Executes a child program asynchronously (your program will not
 * block waiting for the child to exit). The child program is
 * specified by the only argument that must be provided, @argv. @argv
480
 * should be a %NULL-terminated array of strings, to be passed as the
Havoc Pennington's avatar
Havoc Pennington committed
481 482
 * argument vector for the child. The first string in @argv is of
 * course the name of the program to execute. By default, the name of
483
 * the program must be a full path; the <envar>PATH</envar> shell variable 
Matthias Clasen's avatar
Matthias Clasen committed
484
 * will only be searched if you pass the %G_SPAWN_SEARCH_PATH flag.
485 486
 * If the program name is not a full path and %G_SPAWN_SEARCH_PATH flag is not
 * used, then the program will be run from the current directory (or
Stef Walter's avatar
Stef Walter committed
487
 * @working_directory, if specified); this might be unexpected or even
488
 * dangerous in some cases when the current directory is world-writable.
Havoc Pennington's avatar
Havoc Pennington committed
489
 *
490 491 492
 * On Windows, note that all the string or string vector arguments to
 * this function and the other g_spawn*() functions are in UTF-8, the
 * GLib file name encoding. Unicode characters that are not part of
Matthias Clasen's avatar
Matthias Clasen committed
493
 * the system codepage passed in these arguments will be correctly
494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509
 * available in the spawned program only if it uses wide character API
 * to retrieve its command line. For C programs built with Microsoft's
 * tools it is enough to make the program have a wmain() instead of
 * main(). wmain() has a wide character argument vector as parameter.
 *
 * At least currently, mingw doesn't support wmain(), so if you use
 * mingw to develop the spawned program, it will have to call the
 * undocumented function __wgetmainargs() to get the wide character
 * argument vector and environment. See gspawn-win32-helper.c in the
 * GLib sources or init.c in the mingw runtime sources for a prototype
 * for that function. Alternatively, you can retrieve the Win32 system
 * level wide character command line passed to the spawned program
 * using the GetCommandLineW() function.
 *
 * On Windows the low-level child process creation API
 * <function>CreateProcess()</function> doesn't use argument vectors,
510 511 512
 * but a command line. The C runtime library's
 * <function>spawn*()</function> family of functions (which
 * g_spawn_async_with_pipes() eventually calls) paste the argument
513
 * vector elements together into a command line, and the C runtime startup code
514
 * does a corresponding reconstruction of an argument vector from the
515
 * command line, to be passed to main(). Complications arise when you have
516
 * argument vector elements that contain spaces of double quotes. The
517
 * <function>spawn*()</function> functions don't do any quoting or
518 519 520 521 522
 * escaping, but on the other hand the startup code does do unquoting
 * and unescaping in order to enable receiving arguments with embedded
 * spaces or double quotes. To work around this asymmetry,
 * g_spawn_async_with_pipes() will do quoting and escaping on argument
 * vector elements that need it before calling the C runtime
523
 * spawn() function.
524
 *
525 526 527 528
 * The returned @child_pid on Windows is a handle to the child
 * process, not its identifier. Process handles and process
 * identifiers are different concepts on Windows.
 *
529
 * @envp is a %NULL-terminated array of strings, where each string
Havoc Pennington's avatar
Havoc Pennington committed
530
 * has the form <literal>KEY=VALUE</literal>. This will become
Matthias Clasen's avatar
Matthias Clasen committed
531
 * the child's environment. If @envp is %NULL, the child inherits its
Havoc Pennington's avatar
Havoc Pennington committed
532 533 534
 * parent's environment.
 *
 * @flags should be the bitwise OR of any flags you want to affect the
535 536 537 538 539 540
 * function's behaviour. The %G_SPAWN_DO_NOT_REAP_CHILD means that the
 * child will not automatically be reaped; you must use a child watch to
 * be notified about the death of the child process. Eventually you must
 * call g_spawn_close_pid() on the @child_pid, in order to free
 * resources which may be associated with the child process. (On Unix,
 * using a child watch is equivalent to calling waitpid() or handling
Stef Walter's avatar
Stef Walter committed
541
 * the <literal>SIGCHLD</literal> signal manually. On Windows, calling g_spawn_close_pid()
542 543
 * is equivalent to calling CloseHandle() on the process handle returned
 * in @child_pid).  See g_child_watch_add().
544
 *
Havoc Pennington's avatar
Havoc Pennington committed
545 546 547
 * %G_SPAWN_LEAVE_DESCRIPTORS_OPEN means that the parent's open file
 * descriptors will be inherited by the child; otherwise all
 * descriptors except stdin/stdout/stderr will be closed before
548
 * calling exec() in the child. %G_SPAWN_SEARCH_PATH 
Matthias Clasen's avatar
Matthias Clasen committed
549
 * means that <literal>argv[0]</literal> need not be an absolute path, it
550
 * will be looked for in the user's <envar>PATH</envar>. 
551
 * %G_SPAWN_STDOUT_TO_DEV_NULL means that the child's standard output will 
Matthias Clasen's avatar
Matthias Clasen committed
552
 * be discarded, instead of going to the same location as the parent's 
553
 * standard output. If you use this flag, @standard_output must be %NULL.
Havoc Pennington's avatar
Havoc Pennington committed
554
 * %G_SPAWN_STDERR_TO_DEV_NULL means that the child's standard error
555 556 557 558 559
 * will be discarded, instead of going to the same location as the parent's
 * standard error. If you use this flag, @standard_error must be %NULL.
 * %G_SPAWN_CHILD_INHERITS_STDIN means that the child will inherit the parent's
 * standard input (by default, the child's standard input is attached to
 * /dev/null). If you use this flag, @standard_input must be %NULL.
560 561 562 563 564
 * %G_SPAWN_FILE_AND_ARGV_ZERO means that the first element of @argv is
 * the file to execute, while the remaining elements are the
 * actual argument vector to pass to the file. Normally
 * g_spawn_async_with_pipes() uses @argv[0] as the file to execute, and
 * passes all of @argv to the child.
Havoc Pennington's avatar
Havoc Pennington committed
565
 *
566 567 568 569
 * @child_setup and @user_data are a function and user data. On POSIX
 * platforms, the function is called in the child after GLib has
 * performed all the setup it plans to perform (including creating
 * pipes, closing file descriptors, etc.) but before calling
570 571
 * exec(). That is, @child_setup is called just
 * before calling exec() in the child. Obviously
572
 * actions taken in this function will only affect the child, not the
573 574 575 576 577 578
 * parent.
 *
 * On Windows, there is no separate fork() and exec()
 * functionality. Child processes are created and run with a single
 * API call, CreateProcess(). There is no sensible thing @child_setup
 * could be used for on Windows so it is ignored and not called.
Havoc Pennington's avatar
Havoc Pennington committed
579
 *
580 581
 * If non-%NULL, @child_pid will on Unix be filled with the child's
 * process ID. You can use the process ID to send signals to the
Matthias Clasen's avatar
Matthias Clasen committed
582
 * child, or to use g_child_watch_add() (or waitpid()) if you specified the
583 584 585 586 587
 * %G_SPAWN_DO_NOT_REAP_CHILD flag. On Windows, @child_pid will be
 * filled with a handle to the child process only if you specified the
 * %G_SPAWN_DO_NOT_REAP_CHILD flag. You can then access the child
 * process using the Win32 API, for example wait for its termination
 * with the <function>WaitFor*()</function> functions, or examine its
588
 * exit code with GetExitCodeProcess(). You should close the handle 
589
 * with CloseHandle() or g_spawn_close_pid() when you no longer need it.
Havoc Pennington's avatar
Havoc Pennington committed
590
 *
Matthias Clasen's avatar
Matthias Clasen committed
591
 * If non-%NULL, the @standard_input, @standard_output, @standard_error
Havoc Pennington's avatar
Havoc Pennington committed
592 593 594
 * locations will be filled with file descriptors for writing to the child's
 * standard input or reading from its standard output or standard error.
 * The caller of g_spawn_async_with_pipes() must close these file descriptors
595 596 597
 * when they are no longer in use. If these parameters are %NULL, the corresponding
 * pipe won't be created.
 *
598 599
 * If @standard_input is NULL, the child's standard input is attached to 
 * /dev/null unless %G_SPAWN_CHILD_INHERITS_STDIN is set.
600
 *
601 602 603
 * If @standard_error is NULL, the child's standard error goes to the same 
 * location as the parent's standard error unless %G_SPAWN_STDERR_TO_DEV_NULL 
 * is set.
604
 *
605 606 607
 * If @standard_output is NULL, the child's standard output goes to the same 
 * location as the parent's standard output unless %G_SPAWN_STDOUT_TO_DEV_NULL 
 * is set.
Havoc Pennington's avatar
Havoc Pennington committed
608
 *
Matthias Clasen's avatar
Matthias Clasen committed
609 610
 * @error can be %NULL to ignore errors, or non-%NULL to report errors.
 * If an error is set, the function returns %FALSE. Errors
Havoc Pennington's avatar
Havoc Pennington committed
611 612 613 614 615 616 617
 * are reported even if they occur in the child (for example if the
 * executable in <literal>argv[0]</literal> is not found). Typically
 * the <literal>message</literal> field of returned errors should be displayed
 * to users. Possible errors are those from the #G_SPAWN_ERROR domain.
 *
 * If an error occurs, @child_pid, @standard_input, @standard_output,
 * and @standard_error will not be filled with valid values.
Owen Taylor's avatar
Owen Taylor committed
618 619
 *
 * If @child_pid is not %NULL and an error does not occur then the returned
620
 * process reference must be closed using g_spawn_close_pid().
621 622 623 624
 *
 * <note><para>
 * If you are writing a GTK+ application, and the program you 
 * are spawning is a graphical application, too, then you may
Stef Walter's avatar
Stef Walter committed
625
 * want to use gdk_spawn_on_screen_with_pipes() instead to ensure that
Matthias Clasen's avatar
Matthias Clasen committed
626
 * the spawned program opens its windows on the right screen.
627
 * </para></note>
Havoc Pennington's avatar
Havoc Pennington committed
628
 * 
Matthias Clasen's avatar
Matthias Clasen committed
629
 * Return value: %TRUE on success, %FALSE if an error was set
Havoc Pennington's avatar
Havoc Pennington committed
630 631 632 633 634 635 636 637
 **/
gboolean
g_spawn_async_with_pipes (const gchar          *working_directory,
                          gchar               **argv,
                          gchar               **envp,
                          GSpawnFlags           flags,
                          GSpawnChildSetupFunc  child_setup,
                          gpointer              user_data,
Owen Taylor's avatar
Owen Taylor committed
638
                          GPid                 *child_pid,
Havoc Pennington's avatar
Havoc Pennington committed
639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661
                          gint                 *standard_input,
                          gint                 *standard_output,
                          gint                 *standard_error,
                          GError              **error)
{
  g_return_val_if_fail (argv != NULL, FALSE);
  g_return_val_if_fail (standard_output == NULL ||
                        !(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE);
  g_return_val_if_fail (standard_error == NULL ||
                        !(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE);
  /* can't inherit stdin if we have an input pipe. */
  g_return_val_if_fail (standard_input == NULL ||
                        !(flags & G_SPAWN_CHILD_INHERITS_STDIN), FALSE);
  
  return fork_exec_with_pipes (!(flags & G_SPAWN_DO_NOT_REAP_CHILD),
                               working_directory,
                               argv,
                               envp,
                               !(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
                               (flags & G_SPAWN_SEARCH_PATH) != 0,
                               (flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0,
                               (flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0,
                               (flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0,
662
                               (flags & G_SPAWN_FILE_AND_ARGV_ZERO) != 0,
Havoc Pennington's avatar
Havoc Pennington committed
663 664 665 666 667 668 669 670 671 672 673 674
                               child_setup,
                               user_data,
                               child_pid,
                               standard_input,
                               standard_output,
                               standard_error,
                               error);
}

/**
 * g_spawn_command_line_sync:
 * @command_line: a command line 
Colin Walters's avatar
Colin Walters committed
675 676
 * @standard_output: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child output
 * @standard_error: (out) (array zero-terminated=1) (element-type guint8) (allow-none): return location for child errors
677
 * @exit_status: (out) (allow-none): return location for child exit status, as returned by waitpid()
Havoc Pennington's avatar
Havoc Pennington committed
678 679 680 681 682 683 684 685 686 687
 * @error: return location for errors
 *
 * A simple version of g_spawn_sync() with little-used parameters
 * removed, taking a command line instead of an argument vector.  See
 * g_spawn_sync() for full details. @command_line will be parsed by
 * g_shell_parse_argv(). Unlike g_spawn_sync(), the %G_SPAWN_SEARCH_PATH flag
 * is enabled. Note that %G_SPAWN_SEARCH_PATH can have security
 * implications, so consider using g_spawn_sync() directly if
 * appropriate. Possible errors are those from g_spawn_sync() and those
 * from g_shell_parse_argv().
688 689 690 691
 *
 * If @exit_status is non-%NULL, the exit status of the child is stored there as
 * it would be returned by waitpid(); standard UNIX macros such as WIFEXITED()
 * and WEXITSTATUS() must be used to evaluate the exit status.
Havoc Pennington's avatar
Havoc Pennington committed
692
 * 
693
 * On Windows, please note the implications of g_shell_parse_argv()
694 695 696
 * parsing @command_line. Parsing is done according to Unix shell rules, not 
 * Windows command interpreter rules.
 * Space is a separator, and backslashes are
697 698 699 700 701
 * special. Thus you cannot simply pass a @command_line containing
 * canonical Windows paths, like "c:\\program files\\app\\app.exe", as
 * the backslashes will be eaten, and the space will act as a
 * separator. You need to enclose such paths with single quotes, like
 * "'c:\\program files\\app\\app.exe' 'e:\\folder\\argument.txt'".
702
 *
Matthias Clasen's avatar
Matthias Clasen committed
703
 * Return value: %TRUE on success, %FALSE if an error was set
Havoc Pennington's avatar
Havoc Pennington committed
704 705 706 707 708 709 710 711 712
 **/
gboolean
g_spawn_command_line_sync (const gchar  *command_line,
                           gchar       **standard_output,
                           gchar       **standard_error,
                           gint         *exit_status,
                           GError      **error)
{
  gboolean retval;
713
  gchar **argv = NULL;
Havoc Pennington's avatar
Havoc Pennington committed
714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749

  g_return_val_if_fail (command_line != NULL, FALSE);
  
  if (!g_shell_parse_argv (command_line,
                           NULL, &argv,
                           error))
    return FALSE;
  
  retval = g_spawn_sync (NULL,
                         argv,
                         NULL,
                         G_SPAWN_SEARCH_PATH,
                         NULL,
                         NULL,
                         standard_output,
                         standard_error,
                         exit_status,
                         error);
  g_strfreev (argv);

  return retval;
}

/**
 * g_spawn_command_line_async:
 * @command_line: a command line
 * @error: return location for errors
 * 
 * A simple version of g_spawn_async() that parses a command line with
 * g_shell_parse_argv() and passes it to g_spawn_async(). Runs a
 * command line in the background. Unlike g_spawn_async(), the
 * %G_SPAWN_SEARCH_PATH flag is enabled, other flags are not. Note
 * that %G_SPAWN_SEARCH_PATH can have security implications, so
 * consider using g_spawn_async() directly if appropriate. Possible
 * errors are those from g_shell_parse_argv() and g_spawn_async().
 * 
750 751
 * The same concerns on Windows apply as for g_spawn_command_line_sync().
 *
Matthias Clasen's avatar
Matthias Clasen committed
752
 * Return value: %TRUE on success, %FALSE if error is set.
Havoc Pennington's avatar
Havoc Pennington committed
753 754 755 756 757 758
 **/
gboolean
g_spawn_command_line_async (const gchar *command_line,
                            GError     **error)
{
  gboolean retval;
759
  gchar **argv = NULL;
Havoc Pennington's avatar
Havoc Pennington committed
760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799

  g_return_val_if_fail (command_line != NULL, FALSE);

  if (!g_shell_parse_argv (command_line,
                           NULL, &argv,
                           error))
    return FALSE;
  
  retval = g_spawn_async (NULL,
                          argv,
                          NULL,
                          G_SPAWN_SEARCH_PATH,
                          NULL,
                          NULL,
                          NULL,
                          error);
  g_strfreev (argv);

  return retval;
}

static gint
exec_err_to_g_error (gint en)
{
  switch (en)
    {
#ifdef EACCES
    case EACCES:
      return G_SPAWN_ERROR_ACCES;
      break;
#endif

#ifdef EPERM
    case EPERM:
      return G_SPAWN_ERROR_PERM;
      break;
#endif

#ifdef E2BIG
    case E2BIG:
800
      return G_SPAWN_ERROR_TOO_BIG;
Havoc Pennington's avatar
Havoc Pennington committed
801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887
      break;
#endif

#ifdef ENOEXEC
    case ENOEXEC:
      return G_SPAWN_ERROR_NOEXEC;
      break;
#endif

#ifdef ENAMETOOLONG
    case ENAMETOOLONG:
      return G_SPAWN_ERROR_NAMETOOLONG;
      break;
#endif

#ifdef ENOENT
    case ENOENT:
      return G_SPAWN_ERROR_NOENT;
      break;
#endif

#ifdef ENOMEM
    case ENOMEM:
      return G_SPAWN_ERROR_NOMEM;
      break;
#endif

#ifdef ENOTDIR
    case ENOTDIR:
      return G_SPAWN_ERROR_NOTDIR;
      break;
#endif

#ifdef ELOOP
    case ELOOP:
      return G_SPAWN_ERROR_LOOP;
      break;
#endif
      
#ifdef ETXTBUSY
    case ETXTBUSY:
      return G_SPAWN_ERROR_TXTBUSY;
      break;
#endif

#ifdef EIO
    case EIO:
      return G_SPAWN_ERROR_IO;
      break;
#endif

#ifdef ENFILE
    case ENFILE:
      return G_SPAWN_ERROR_NFILE;
      break;
#endif

#ifdef EMFILE
    case EMFILE:
      return G_SPAWN_ERROR_MFILE;
      break;
#endif

#ifdef EINVAL
    case EINVAL:
      return G_SPAWN_ERROR_INVAL;
      break;
#endif

#ifdef EISDIR
    case EISDIR:
      return G_SPAWN_ERROR_ISDIR;
      break;
#endif

#ifdef ELIBBAD
    case ELIBBAD:
      return G_SPAWN_ERROR_LIBBAD;
      break;
#endif
      
    default:
      return G_SPAWN_ERROR_FAILED;
      break;
    }
}

888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910
static gssize
write_all (gint fd, gconstpointer vbuf, gsize to_write)
{
  gchar *buf = (gchar *) vbuf;
  
  while (to_write > 0)
    {
      gssize count = write (fd, buf, to_write);
      if (count < 0)
        {
          if (errno != EINTR)
            return FALSE;
        }
      else
        {
          to_write -= count;
          buf += count;
        }
    }
  
  return TRUE;
}

911
G_GNUC_NORETURN
Havoc Pennington's avatar
Havoc Pennington committed
912 913 914 915 916
static void
write_err_and_exit (gint fd, gint msg)
{
  gint en = errno;
  
917 918
  write_all (fd, &msg, sizeof(msg));
  write_all (fd, &en, sizeof(en));
Havoc Pennington's avatar
Havoc Pennington committed
919 920 921 922
  
  _exit (1);
}

923
static int
924
set_cloexec (void *data, gint fd)
Havoc Pennington's avatar
Havoc Pennington committed
925
{
926
  if (fd >= GPOINTER_TO_INT (data))
927
    fcntl (fd, F_SETFD, FD_CLOEXEC);
928 929

  return 0;
Havoc Pennington's avatar
Havoc Pennington committed
930 931
}

932 933 934 935 936 937
#ifndef HAVE_FDWALK
static int
fdwalk (int (*cb)(void *data, int fd), void *data)
{
  gint open_max;
  gint fd;
938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
  gint res = 0;
  
#ifdef HAVE_SYS_RESOURCE_H
  struct rlimit rl;
#endif

#ifdef __linux__  
  DIR *d;

  if ((d = opendir("/proc/self/fd"))) {
      struct dirent *de;

      while ((de = readdir(d))) {
          glong l;
          gchar *e = NULL;

          if (de->d_name[0] == '.')
              continue;
            
          errno = 0;
          l = strtol(de->d_name, &e, 10);
          if (errno != 0 || !e || *e)
              continue;

          fd = (gint) l;

          if ((glong) fd != l)
              continue;

          if (fd == dirfd(d))
              continue;

          if ((res = cb (data, fd)) != 0)
              break;
        }
      
      closedir(d);
      return res;
  }
977

978 979 980 981 982 983 984
  /* If /proc is not mounted or not accessible we fall back to the old
   * rlimit trick */

#endif
  
#ifdef HAVE_SYS_RESOURCE_H
      
Matthias Clasen's avatar
Matthias Clasen committed
985
  if (getrlimit(RLIMIT_NOFILE, &rl) == 0 && rl.rlim_max != RLIM_INFINITY)
986 987 988 989 990 991 992 993
      open_max = rl.rlim_max;
  else
#endif
      open_max = sysconf (_SC_OPEN_MAX);

  for (fd = 0; fd < open_max; fd++)
      if ((res = cb (data, fd)) != 0)
          break;
994 995 996 997 998

  return res;
}
#endif

Havoc Pennington's avatar
Havoc Pennington committed
999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011
static gint
sane_dup2 (gint fd1, gint fd2)
{
  gint ret;

 retry:
  ret = dup2 (fd1, fd2);
  if (ret < 0 && errno == EINTR)
    goto retry;

  return ret;
}

1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024
static gint
sane_open (const char *path, gint mode)
{
  gint ret;

 retry:
  ret = open (path, mode);
  if (ret < 0 && errno == EINTR)
    goto retry;

  return ret;
}

Havoc Pennington's avatar
Havoc Pennington committed
1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045
enum
{
  CHILD_CHDIR_FAILED,
  CHILD_EXEC_FAILED,
  CHILD_DUP2_FAILED,
  CHILD_FORK_FAILED
};

static void
do_exec (gint                  child_err_report_fd,
         gint                  stdin_fd,
         gint                  stdout_fd,
         gint                  stderr_fd,
         const gchar          *working_directory,
         gchar               **argv,
         gchar               **envp,
         gboolean              close_descriptors,
         gboolean              search_path,
         gboolean              stdout_to_null,
         gboolean              stderr_to_null,
         gboolean              child_inherits_stdin,
1046
         gboolean              file_and_argv_zero,
Havoc Pennington's avatar
Havoc Pennington committed
1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060
         GSpawnChildSetupFunc  child_setup,
         gpointer              user_data)
{
  if (working_directory && chdir (working_directory) < 0)
    write_err_and_exit (child_err_report_fd,
                        CHILD_CHDIR_FAILED);

  /* Close all file descriptors but stdin stdout and stderr as
   * soon as we exec. Note that this includes
   * child_err_report_fd, which keeps the parent from blocking
   * forever on the other end of that pipe.
   */
  if (close_descriptors)
    {
1061
      fdwalk (set_cloexec, GINT_TO_POINTER(3));
Havoc Pennington's avatar
Havoc Pennington committed
1062 1063 1064 1065
    }
  else
    {
      /* We need to do child_err_report_fd anyway */
1066
      set_cloexec (GINT_TO_POINTER(0), child_err_report_fd);
Havoc Pennington's avatar
Havoc Pennington committed
1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102
    }
  
  /* Redirect pipes as required */
  
  if (stdin_fd >= 0)
    {
      /* dup2 can't actually fail here I don't think */
          
      if (sane_dup2 (stdin_fd, 0) < 0)
        write_err_and_exit (child_err_report_fd,
                            CHILD_DUP2_FAILED);

      /* ignore this if it doesn't work */
      close_and_invalidate (&stdin_fd);
    }
  else if (!child_inherits_stdin)
    {
      /* Keep process from blocking on a read of stdin */
      gint read_null = open ("/dev/null", O_RDONLY);
      sane_dup2 (read_null, 0);
      close_and_invalidate (&read_null);
    }

  if (stdout_fd >= 0)
    {
      /* dup2 can't actually fail here I don't think */
          
      if (sane_dup2 (stdout_fd, 1) < 0)
        write_err_and_exit (child_err_report_fd,
                            CHILD_DUP2_FAILED);

      /* ignore this if it doesn't work */
      close_and_invalidate (&stdout_fd);
    }
  else if (stdout_to_null)
    {
1103
      gint write_null = sane_open ("/dev/null", O_WRONLY);
Havoc Pennington's avatar
Havoc Pennington committed
1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120
      sane_dup2 (write_null, 1);
      close_and_invalidate (&write_null);
    }

  if (stderr_fd >= 0)
    {
      /* dup2 can't actually fail here I don't think */
          
      if (sane_dup2 (stderr_fd, 2) < 0)
        write_err_and_exit (child_err_report_fd,
                            CHILD_DUP2_FAILED);

      /* ignore this if it doesn't work */
      close_and_invalidate (&stderr_fd);
    }
  else if (stderr_to_null)
    {
1121
      gint write_null = sane_open ("/dev/null", O_WRONLY);
Havoc Pennington's avatar
Havoc Pennington committed
1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
      sane_dup2 (write_null, 2);
      close_and_invalidate (&write_null);
    }
  
  /* Call user function just before we exec */
  if (child_setup)
    {
      (* child_setup) (user_data);
    }

1132 1133 1134
  g_execute (argv[0],
             file_and_argv_zero ? argv + 1 : argv,
             envp, search_path);
Havoc Pennington's avatar
Havoc Pennington committed
1135 1136 1137 1138 1139 1140 1141 1142 1143

  /* Exec failed */
  write_err_and_exit (child_err_report_fd,
                      CHILD_EXEC_FAILED);
}

static gboolean
read_ints (int      fd,
           gint*    buf,
1144 1145
           gint     n_ints_in_buf,    
           gint    *n_ints_read,      
Havoc Pennington's avatar
Havoc Pennington committed
1146 1147
           GError **error)
{
1148
  gsize bytes = 0;    
Havoc Pennington's avatar
Havoc Pennington committed
1149 1150 1151
  
  while (TRUE)
    {
1152
      gssize chunk;    
Havoc Pennington's avatar
Havoc Pennington committed
1153 1154 1155 1156 1157 1158 1159 1160 1161

      if (bytes >= sizeof(gint)*2)
        break; /* give up, who knows what happened, should not be
                * possible.
                */
          
    again:
      chunk = read (fd,
                    ((gchar*)buf) + bytes,
1162
                    sizeof(gint) * n_ints_in_buf - bytes);
Havoc Pennington's avatar
Havoc Pennington committed
1163 1164 1165 1166 1167
      if (chunk < 0 && errno == EINTR)
        goto again;
          
      if (chunk < 0)
        {
Christian Persch's avatar
Christian Persch committed
1168 1169
          int errsv = errno;

Havoc Pennington's avatar
Havoc Pennington committed
1170 1171 1172 1173 1174
          /* Some weird shit happened, bail out */
          g_set_error (error,
                       G_SPAWN_ERROR,
                       G_SPAWN_ERROR_FAILED,
                       _("Failed to read from child pipe (%s)"),
Christian Persch's avatar
Christian Persch committed
1175
                       g_strerror (errsv));
Havoc Pennington's avatar
Havoc Pennington committed
1176 1177 1178 1179 1180

          return FALSE;
        }
      else if (chunk == 0)
        break; /* EOF */
1181 1182
      else /* chunk > 0 */
	bytes += chunk;
Havoc Pennington's avatar
Havoc Pennington committed
1183 1184
    }

1185
  *n_ints_read = (gint)(bytes / sizeof(gint));
Havoc Pennington's avatar
Havoc Pennington committed
1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199

  return TRUE;
}

static gboolean
fork_exec_with_pipes (gboolean              intermediate_child,
                      const gchar          *working_directory,
                      gchar               **argv,
                      gchar               **envp,
                      gboolean              close_descriptors,
                      gboolean              search_path,
                      gboolean              stdout_to_null,
                      gboolean              stderr_to_null,
                      gboolean              child_inherits_stdin,
1200
                      gboolean              file_and_argv_zero,
Havoc Pennington's avatar
Havoc Pennington committed
1201 1202
                      GSpawnChildSetupFunc  child_setup,
                      gpointer              user_data,
Owen Taylor's avatar
Owen Taylor committed
1203
                      GPid                 *child_pid,
Havoc Pennington's avatar
Havoc Pennington committed
1204 1205 1206 1207 1208
                      gint                 *standard_input,
                      gint                 *standard_output,
                      gint                 *standard_error,
                      GError              **error)     
{
Owen Taylor's avatar
Owen Taylor committed
1209
  GPid pid = -1;
Havoc Pennington's avatar
Havoc Pennington committed
1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231
  gint stdin_pipe[2] = { -1, -1 };
  gint stdout_pipe[2] = { -1, -1 };
  gint stderr_pipe[2] = { -1, -1 };
  gint child_err_report_pipe[2] = { -1, -1 };
  gint child_pid_report_pipe[2] = { -1, -1 };
  gint status;
  
  if (!make_pipe (child_err_report_pipe, error))
    return FALSE;

  if (intermediate_child && !make_pipe (child_pid_report_pipe, error))
    goto cleanup_and_fail;
  
  if (standard_input && !make_pipe (stdin_pipe, error))
    goto cleanup_and_fail;
  
  if (standard_output && !make_pipe (stdout_pipe, error))
    goto cleanup_and_fail;

  if (standard_error && !make_pipe (stderr_pipe, error))
    goto cleanup_and_fail;

1232
  pid = fork ();
Havoc Pennington's avatar
Havoc Pennington committed
1233 1234

  if (pid < 0)
Christian Persch's avatar
Christian Persch committed
1235 1236 1237
    {
      int errsv = errno;

Havoc Pennington's avatar
Havoc Pennington committed
1238 1239 1240 1241
      g_set_error (error,
                   G_SPAWN_ERROR,
                   G_SPAWN_ERROR_FORK,
                   _("Failed to fork (%s)"),
Christian Persch's avatar
Christian Persch committed
1242
                   g_strerror (errsv));
Havoc Pennington's avatar
Havoc Pennington committed
1243 1244 1245 1246 1247 1248 1249 1250

      goto cleanup_and_fail;
    }
  else if (pid == 0)
    {
      /* Immediate child. This may or may not be the child that
       * actually execs the new process.
       */
1251 1252 1253 1254 1255 1256

      /* Reset some signal handlers that we may use */
      signal (SIGCHLD, SIG_DFL);
      signal (SIGINT, SIG_DFL);
      signal (SIGTERM, SIG_DFL);
      signal (SIGHUP, SIG_DFL);
Havoc Pennington's avatar
Havoc Pennington committed
1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279
      
      /* Be sure we crash if the parent exits
       * and we write to the err_report_pipe
       */
      signal (SIGPIPE, SIG_DFL);

      /* Close the parent's end of the pipes;
       * not needed in the close_descriptors case,
       * though
       */
      close_and_invalidate (&child_err_report_pipe[0]);
      close_and_invalidate (&child_pid_report_pipe[0]);
      close_and_invalidate (&stdin_pipe[1]);
      close_and_invalidate (&stdout_pipe[0]);
      close_and_invalidate (&stderr_pipe[0]);
      
      if (intermediate_child)
        {
          /* We need to fork an intermediate child that launches the
           * final child. The purpose of the intermediate child
           * is to exit, so we can waitpid() it immediately.
           * Then the grandchild will not become a zombie.
           */
Owen Taylor's avatar
Owen Taylor committed
1280
          GPid grandchild_pid;
Havoc Pennington's avatar
Havoc Pennington committed
1281

1282
          grandchild_pid = fork ();
Havoc Pennington's avatar
Havoc Pennington committed
1283 1284 1285 1286

          if (grandchild_pid < 0)
            {
              /* report -1 as child PID */
1287 1288
              write_all (child_pid_report_pipe[1], &grandchild_pid,
                         sizeof(grandchild_pid));
Havoc Pennington's avatar
Havoc Pennington committed
1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306
              
              write_err_and_exit (child_err_report_pipe[1],
                                  CHILD_FORK_FAILED);              
            }
          else if (grandchild_pid == 0)
            {
              do_exec (child_err_report_pipe[1],
                       stdin_pipe[0],
                       stdout_pipe[1],
                       stderr_pipe[1],
                       working_directory,
                       argv,
                       envp,
                       close_descriptors,
                       search_path,
                       stdout_to_null,
                       stderr_to_null,
                       child_inherits_stdin,
1307
                       file_and_argv_zero,
Havoc Pennington's avatar
Havoc Pennington committed
1308 1309 1310 1311 1312
                       child_setup,
                       user_data);
            }
          else
            {
1313
              write_all (child_pid_report_pipe[1], &grandchild_pid, sizeof(grandchild_pid));
Havoc Pennington's avatar
Havoc Pennington committed
1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335
              close_and_invalidate (&child_pid_report_pipe[1]);
              
              _exit (0);
            }
        }
      else
        {
          /* Just run the child.
           */

          do_exec (child_err_report_pipe[1],
                   stdin_pipe[0],
                   stdout_pipe[1],
                   stderr_pipe[1],
                   working_directory,
                   argv,
                   envp,
                   close_descriptors,
                   search_path,
                   stdout_to_null,
                   stderr_to_null,
                   child_inherits_stdin,
1336
                   file_and_argv_zero,
Havoc Pennington's avatar
Havoc Pennington committed
1337 1338 1339 1340 1341 1342 1343 1344 1345
                   child_setup,
                   user_data);
        }
    }
  else
    {
      /* Parent */
      
      gint buf[2];
1346
      gint n_ints = 0;    
Havoc Pennington's avatar
Havoc Pennington committed
1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365

      /* Close the uncared-about ends of the pipes */
      close_and_invalidate (&child_err_report_pipe[1]);
      close_and_invalidate (&child_pid_report_pipe[1]);
      close_and_invalidate (&stdin_pipe[0]);
      close_and_invalidate (&stdout_pipe[1]);
      close_and_invalidate (&stderr_pipe[1]);

      /* If we had an intermediate child, reap it */
      if (intermediate_child)
        {
        wait_again:
          if (waitpid (pid, &status, 0) < 0)
            {
              if (errno == EINTR)
                goto wait_again;
              else if (errno == ECHILD)
                ; /* do nothing, child already reaped */
              else
1366 1367
                g_warning ("waitpid() should not fail in "
			   "'fork_exec_with_pipes'");
Havoc Pennington's avatar
Havoc Pennington committed
1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396
            }
        }
      

      if (!read_ints (child_err_report_pipe[0],
                      buf, 2, &n_ints,
                      error))
        goto cleanup_and_fail;
        
      if (n_ints >= 2)
        {
          /* Error from the child. */

          switch (buf[0])
            {
            case CHILD_CHDIR_FAILED:
              g_set_error (error,
                           G_SPAWN_ERROR,
                           G_SPAWN_ERROR_CHDIR,
                           _("Failed to change to directory '%s' (%s)"),
                           working_directory,
                           g_strerror (buf[1]));

              break;
              
            case CHILD_EXEC_FAILED:
              g_set_error (error,
                           G_SPAWN_ERROR,
                           exec_err_to_g_error (buf[1]),
1397 1398
                           _("Failed to execute child process \"%s\" (%s)"),
                           argv[0],
Havoc Pennington's avatar
Havoc Pennington committed
1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
                           g_strerror (buf[1]));

              break;
              
            case CHILD_DUP2_FAILED:
              g_set_error (error,
                           G_SPAWN_ERROR,
                           G_SPAWN_ERROR_FAILED,
                           _("Failed to redirect output or input of child process (%s)"),
                           g_strerror (buf[1]));

              break;

            case CHILD_FORK_FAILED:
              g_set_error (error,
                           G_SPAWN_ERROR,
                           G_SPAWN_ERROR_FORK,
                           _("Failed to fork child process (%s)"),
                           g_strerror (buf[1]));
              break;
              
            default:
              g_set_error (error,
                           G_SPAWN_ERROR,
                           G_SPAWN_ERROR_FAILED,
1424 1425
                           _("Unknown error executing child process \"%s\""),
                           argv[0]);
Havoc Pennington's avatar
Havoc Pennington committed
1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442
              break;
            }

          goto cleanup_and_fail;
        }

      /* Get child pid from intermediate child pipe. */
      if (intermediate_child)
        {
          n_ints = 0;
          
          if (!read_ints (child_pid_report_pipe[0],
                          buf, 1, &n_ints, error))
            goto cleanup_and_fail;

          if (n_ints < 1)
            {
Christian Persch's avatar
Christian Persch committed
1443 1444
              int errsv = errno;

Havoc Pennington's avatar
Havoc Pennington committed
1445 1446 1447 1448
              g_set_error (error,
                           G_SPAWN_ERROR,
                           G_SPAWN_ERROR_FAILED,
                           _("Failed to read enough data from child pid pipe (%s)"),
Christian Persch's avatar
Christian Persch committed
1449
                           g_strerror (errsv));
Havoc Pennington's avatar
Havoc Pennington committed
1450 1451 1452 1453 1454 1455 1456 1457 1458 1459
              goto cleanup_and_fail;
            }
          else
            {
              /* we have the child pid */
              pid = buf[0];
            }
        }
      
      /* Success against all odds! return the information */
1460 1461 1462
      close_and_invalidate (&child_err_report_pipe[0]);
      close_and_invalidate (&child_pid_report_pipe[0]);
 
Havoc Pennington's avatar
Havoc Pennington committed
1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476
      if (child_pid)
        *child_pid = pid;

      if (standard_input)
        *standard_input = stdin_pipe[1];
      if (standard_output)
        *standard_output = stdout_pipe[0];
      if (standard_error)
        *standard_error = stderr_pipe[0];
      
      return TRUE;
    }

 cleanup_and_fail:
1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496

  /* There was an error from the Child, reap the child to avoid it being
     a zombie.
   */

  if (pid > 0)
  {
    wait_failed:
     if (waitpid (pid, NULL, 0) < 0)
       {
          if (errno == EINTR)
            goto wait_failed;
          else if (errno == ECHILD)
            ; /* do nothing, child already reaped */
          else
            g_warning ("waitpid() should not fail in "
                       "'fork_exec_with_pipes'");
       }
   }

Havoc Pennington's avatar
Havoc Pennington committed
1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516
  close_and_invalidate (&child_err_report_pipe[0]);
  close_and_invalidate (&child_err_report_pipe[1]);
  close_and_invalidate (&child_pid_report_pipe[0]);
  close_and_invalidate (&child_pid_report_pipe[1]);
  close_and_invalidate (&stdin_pipe[0]);
  close_and_invalidate (&stdin_pipe[1]);
  close_and_invalidate (&stdout_pipe[0]);
  close_and_invalidate (&stdout_pipe[1]);
  close_and_invalidate (&stderr_pipe[0]);
  close_and_invalidate (&stderr_pipe[1]);

  return FALSE;
}

static gboolean
make_pipe (gint     p[2],
           GError **error)
{
  if (pipe (p) < 0)
    {
1517
      gint errsv = errno;
Havoc Pennington's avatar
Havoc Pennington committed
1518 1519 1520 1521
      g_set_error (error,
                   G_SPAWN_ERROR,
                   G_SPAWN_ERROR_FAILED,
                   _("Failed to create pipe for communicating with child process (%s)"),
1522
                   g_strerror (errsv));
Havoc Pennington's avatar
Havoc Pennington committed
1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545
      return FALSE;
    }
  else
    return TRUE;
}

/* Based on execvp from GNU C Library */

static void
script_execute (const gchar *file,
                gchar      **argv,
                gchar      **envp,
                gboolean     search_path)
{
  /* Count the arguments.  */
  int argc = 0;
  while (argv[argc])
    ++argc;
  
  /* Construct an argument list for the shell.  */
  {
    gchar **new_argv;

1546
    new_argv = g_new0 (gchar*, argc + 2); /* /bin/sh and NULL */
Havoc Pennington's avatar
Havoc Pennington committed
1547 1548 1549
    
    new_argv[0] = (char *) "/bin/sh";
    new_argv[1] = (char *) file;
1550
    while (argc > 0)
Havoc Pennington's avatar
Havoc Pennington committed
1551
      {
1552
	new_argv[argc + 1] = argv[argc];
Havoc Pennington's avatar
Havoc Pennington committed
1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602
	--argc;
      }

    /* Execute the shell. */
    if (envp)
      execve (new_argv[0], new_argv, envp);
    else
      execv (new_argv[0], new_argv);
    
    g_free (new_argv);
  }
}

static gchar*
my_strchrnul (const gchar *str, gchar c)
{
  gchar *p = (gchar*) str;
  while (*p && (*p != c))
    ++p;

  return p;
}

static gint
g_execute (const gchar *file,
           gchar      **argv,
           gchar      **envp,
           gboolean     search_path)
{
  if (*file == '\0')
    {
      /* We check the simple case first. */
      errno = ENOENT;
      return -1;
    }

  if (!search_path || strchr (file, '/') != NULL)
    {
      /* Don't search when it contains a slash. */
      if (envp)
        execve (file, argv, envp);
      else
        execv (file, argv);
      
      if (errno == ENOEXEC)
	script_execute (file, argv, envp, FALSE);
    }
  else
    {
      gboolean got_eacces = 0;
Havoc Pennington's avatar
Havoc Pennington committed
1603 1604
      const gchar *path, *p;
      gchar *name, *freeme;
1605 1606
      gsize len;
      gsize pathlen;
Havoc Pennington's avatar
Havoc Pennington committed
1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682

      path = g_getenv ("PATH");
      if (path == NULL)
	{
	  /* There is no `PATH' in the environment.  The default
	   * search path in libc is the current directory followed by
	   * the path `confstr' returns for `_CS_PATH'.
           */

          /* In GLib we put . last, for security, and don't use the
           * unportable confstr(); UNIX98 does not actually specify
           * what to search if PATH is unset. POSIX may, dunno.
           */
          
          path = "/bin:/usr/bin:.";
	}

      len = strlen (file) + 1;
      pathlen = strlen (path);
      freeme = name = g_malloc (pathlen + len + 1);
      
      /* Copy the file name at the top, including '\0'  */
      memcpy (name + pathlen + 1, file, len);
      name = name + pathlen;
      /* And add the slash before the filename  */
      *name = '/';

      p = path;
      do
	{
	  char *startp;

	  path = p;
	  p = my_strchrnul (path, ':');

	  if (p == path)
	    /* Two adjacent colons, or a colon at the beginning or the end
             * of `PATH' means to search the current directory.
             */
	    startp = name + 1;
	  else
	    startp = memcpy (name - (p - path), path, p - path);

	  /* Try to execute this name.  If it works, execv will not return.  */
          if (envp)
            execve (startp, argv, envp);
          else
            execv (startp, argv);
          
	  if (errno == ENOEXEC)
	    script_execute (startp, argv, envp, search_path);

	  switch (errno)
	    {
	    case EACCES:
	      /* Record the we got a `Permission denied' error.  If we end
               * up finding no executable we can use, we want to diagnose
               * that we did find one but were denied access.
               */
	      got_eacces = TRUE;

              /* FALL THRU */
              
	    case ENOENT:
#ifdef ESTALE
	    case ESTALE:
#endif
#ifdef ENOTDIR
	    case ENOTDIR:
#endif
	      /* Those errors indicate the file is missing or not executable
               * by us, in which case we want to just try the next path
               * directory.
               */
	      break;

1683 1684 1685 1686 1687 1688 1689 1690
	    case ENODEV:
	    case ETIMEDOUT:
	      /* Some strange filesystems like AFS return even
	       * stranger error numbers.  They cannot reasonably mean anything
	       * else so ignore those, too.
	       */
	      break;

Havoc Pennington's avatar
Havoc Pennington committed
1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714
	    default:
	      /* Some other error means we found an executable file, but
               * something went wrong executing it; return the error to our
               * caller.
               */
              g_free (freeme);
	      return -1;
	    }
	}
      while (*p++ != '\0');

      /* We tried every element and none of them worked.  */
      if (got_eacces)
	/* At least one failure was due to permissions, so report that
         * error.
         */
        errno = EACCES;

      g_free (freeme);
    }

  /* Return the error from the last attempt (probably ENOENT).  */
  return -1;
}
Owen Taylor's avatar
Owen Taylor committed
1715 1716 1717

/**
 * g_spawn_close_pid:
1718
 * @pid: The process reference to close
Owen Taylor's avatar
Owen Taylor committed
1719
 *
1720
 * On some platforms, notably Windows, the #GPid type represents a resource
Owen Taylor's avatar
Owen Taylor committed
1721 1722 1723 1724 1725 1726 1727 1728
 * which must be closed to prevent resource leaking. g_spawn_close_pid()
 * is provided for this purpose. It should be used on all platforms, even
 * though it doesn't do anything under UNIX.
 **/
void
g_spawn_close_pid (GPid pid)
{
}