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[binutils.git] / libiberty / pex-unix.c
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1 /* Utilities to execute a program in a subprocess (possibly linked by pipes
2 with other subprocesses), and wait for it. Generic Unix version
3 (also used for UWIN and VMS).
4 Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2009,
5 2010 Free Software Foundation, Inc.
7 This file is part of the libiberty library.
8 Libiberty is free software; you can redistribute it and/or
9 modify it under the terms of the GNU Library General Public
10 License as published by the Free Software Foundation; either
11 version 2 of the License, or (at your option) any later version.
13 Libiberty is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Library General Public License for more details.
18 You should have received a copy of the GNU Library General Public
19 License along with libiberty; see the file COPYING.LIB. If not,
20 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
21 Boston, MA 02110-1301, USA. */
23 #include "config.h"
24 #include "libiberty.h"
25 #include "pex-common.h"
27 #include <stdio.h>
28 #include <signal.h>
29 #include <errno.h>
30 #ifdef NEED_DECLARATION_ERRNO
31 extern int errno;
32 #endif
33 #ifdef HAVE_STDLIB_H
34 #include <stdlib.h>
35 #endif
36 #ifdef HAVE_STRING_H
37 #include <string.h>
38 #endif
39 #ifdef HAVE_UNISTD_H
40 #include <unistd.h>
41 #endif
43 #include <sys/types.h>
45 #ifdef HAVE_FCNTL_H
46 #include <fcntl.h>
47 #endif
48 #ifdef HAVE_SYS_WAIT_H
49 #include <sys/wait.h>
50 #endif
51 #ifdef HAVE_GETRUSAGE
52 #include <sys/time.h>
53 #include <sys/resource.h>
54 #endif
55 #ifdef HAVE_SYS_STAT_H
56 #include <sys/stat.h>
57 #endif
58 #ifdef HAVE_PROCESS_H
59 #include <process.h>
60 #endif
62 #ifdef vfork /* Autoconf may define this to fork for us. */
63 # define VFORK_STRING "fork"
64 #else
65 # define VFORK_STRING "vfork"
66 #endif
67 #ifdef HAVE_VFORK_H
68 #include <vfork.h>
69 #endif
70 #if defined(VMS) && defined (__LONG_POINTERS)
71 #ifndef __CHAR_PTR32
72 typedef char * __char_ptr32
73 __attribute__ ((mode (SI)));
74 #endif
76 typedef __char_ptr32 *__char_ptr_char_ptr32
77 __attribute__ ((mode (SI)));
79 /* Return a 32 bit pointer to an array of 32 bit pointers
80 given a 64 bit pointer to an array of 64 bit pointers. */
82 static __char_ptr_char_ptr32
83 to_ptr32 (char **ptr64)
85 int argc;
86 __char_ptr_char_ptr32 short_argv;
88 for (argc=0; ptr64[argc]; argc++);
90 /* Reallocate argv with 32 bit pointers. */
91 short_argv = (__char_ptr_char_ptr32) decc$malloc
92 (sizeof (__char_ptr32) * (argc + 1));
94 for (argc=0; ptr64[argc]; argc++)
95 short_argv[argc] = (__char_ptr32) decc$strdup (ptr64[argc]);
97 short_argv[argc] = (__char_ptr32) 0;
98 return short_argv;
101 #else
102 #define to_ptr32(argv) argv
103 #endif
105 /* File mode to use for private and world-readable files. */
107 #if defined (S_IRUSR) && defined (S_IWUSR) && defined (S_IRGRP) && defined (S_IWGRP) && defined (S_IROTH) && defined (S_IWOTH)
108 #define PUBLIC_MODE \
109 (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
110 #else
111 #define PUBLIC_MODE 0666
112 #endif
114 /* Get the exit status of a particular process, and optionally get the
115 time that it took. This is simple if we have wait4, slightly
116 harder if we have waitpid, and is a pain if we only have wait. */
118 static pid_t pex_wait (struct pex_obj *, pid_t, int *, struct pex_time *);
120 #ifdef HAVE_WAIT4
122 static pid_t
123 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
124 struct pex_time *time)
126 pid_t ret;
127 struct rusage r;
129 #ifdef HAVE_WAITPID
130 if (time == NULL)
131 return waitpid (pid, status, 0);
132 #endif
134 ret = wait4 (pid, status, 0, &r);
136 if (time != NULL)
138 time->user_seconds = r.ru_utime.tv_sec;
139 time->user_microseconds= r.ru_utime.tv_usec;
140 time->system_seconds = r.ru_stime.tv_sec;
141 time->system_microseconds= r.ru_stime.tv_usec;
144 return ret;
147 #else /* ! defined (HAVE_WAIT4) */
149 #ifdef HAVE_WAITPID
151 #ifndef HAVE_GETRUSAGE
153 static pid_t
154 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
155 struct pex_time *time)
157 if (time != NULL)
158 memset (time, 0, sizeof (struct pex_time));
159 return waitpid (pid, status, 0);
162 #else /* defined (HAVE_GETRUSAGE) */
164 static pid_t
165 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
166 struct pex_time *time)
168 struct rusage r1, r2;
169 pid_t ret;
171 if (time == NULL)
172 return waitpid (pid, status, 0);
174 getrusage (RUSAGE_CHILDREN, &r1);
176 ret = waitpid (pid, status, 0);
177 if (ret < 0)
178 return ret;
180 getrusage (RUSAGE_CHILDREN, &r2);
182 time->user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
183 time->user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
184 if (r2.ru_utime.tv_usec < r1.ru_utime.tv_usec)
186 --time->user_seconds;
187 time->user_microseconds += 1000000;
190 time->system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
191 time->system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
192 if (r2.ru_stime.tv_usec < r1.ru_stime.tv_usec)
194 --time->system_seconds;
195 time->system_microseconds += 1000000;
198 return ret;
201 #endif /* defined (HAVE_GETRUSAGE) */
203 #else /* ! defined (HAVE_WAITPID) */
205 struct status_list
207 struct status_list *next;
208 pid_t pid;
209 int status;
210 struct pex_time time;
213 static pid_t
214 pex_wait (struct pex_obj *obj, pid_t pid, int *status, struct pex_time *time)
216 struct status_list **pp;
218 for (pp = (struct status_list **) &obj->sysdep;
219 *pp != NULL;
220 pp = &(*pp)->next)
222 if ((*pp)->pid == pid)
224 struct status_list *p;
226 p = *pp;
227 *status = p->status;
228 if (time != NULL)
229 *time = p->time;
230 *pp = p->next;
231 free (p);
232 return pid;
236 while (1)
238 pid_t cpid;
239 struct status_list *psl;
240 struct pex_time pt;
241 #ifdef HAVE_GETRUSAGE
242 struct rusage r1, r2;
243 #endif
245 if (time != NULL)
247 #ifdef HAVE_GETRUSAGE
248 getrusage (RUSAGE_CHILDREN, &r1);
249 #else
250 memset (&pt, 0, sizeof (struct pex_time));
251 #endif
254 cpid = wait (status);
256 #ifdef HAVE_GETRUSAGE
257 if (time != NULL && cpid >= 0)
259 getrusage (RUSAGE_CHILDREN, &r2);
261 pt.user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
262 pt.user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
263 if (pt.user_microseconds < 0)
265 --pt.user_seconds;
266 pt.user_microseconds += 1000000;
269 pt.system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
270 pt.system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
271 if (pt.system_microseconds < 0)
273 --pt.system_seconds;
274 pt.system_microseconds += 1000000;
277 #endif
279 if (cpid < 0 || cpid == pid)
281 if (time != NULL)
282 *time = pt;
283 return cpid;
286 psl = XNEW (struct status_list);
287 psl->pid = cpid;
288 psl->status = *status;
289 if (time != NULL)
290 psl->time = pt;
291 psl->next = (struct status_list *) obj->sysdep;
292 obj->sysdep = (void *) psl;
296 #endif /* ! defined (HAVE_WAITPID) */
297 #endif /* ! defined (HAVE_WAIT4) */
299 static void pex_child_error (struct pex_obj *, const char *, const char *, int)
300 ATTRIBUTE_NORETURN;
301 static int pex_unix_open_read (struct pex_obj *, const char *, int);
302 static int pex_unix_open_write (struct pex_obj *, const char *, int);
303 static pid_t pex_unix_exec_child (struct pex_obj *, int, const char *,
304 char * const *, char * const *,
305 int, int, int, int,
306 const char **, int *);
307 static int pex_unix_close (struct pex_obj *, int);
308 static int pex_unix_wait (struct pex_obj *, pid_t, int *, struct pex_time *,
309 int, const char **, int *);
310 static int pex_unix_pipe (struct pex_obj *, int *, int);
311 static FILE *pex_unix_fdopenr (struct pex_obj *, int, int);
312 static FILE *pex_unix_fdopenw (struct pex_obj *, int, int);
313 static void pex_unix_cleanup (struct pex_obj *);
315 /* The list of functions we pass to the common routines. */
317 const struct pex_funcs funcs =
319 pex_unix_open_read,
320 pex_unix_open_write,
321 pex_unix_exec_child,
322 pex_unix_close,
323 pex_unix_wait,
324 pex_unix_pipe,
325 pex_unix_fdopenr,
326 pex_unix_fdopenw,
327 pex_unix_cleanup
330 /* Return a newly initialized pex_obj structure. */
332 struct pex_obj *
333 pex_init (int flags, const char *pname, const char *tempbase)
335 return pex_init_common (flags, pname, tempbase, &funcs);
338 /* Open a file for reading. */
340 static int
341 pex_unix_open_read (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
342 int binary ATTRIBUTE_UNUSED)
344 return open (name, O_RDONLY);
347 /* Open a file for writing. */
349 static int
350 pex_unix_open_write (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
351 int binary ATTRIBUTE_UNUSED)
353 /* Note that we can't use O_EXCL here because gcc may have already
354 created the temporary file via make_temp_file. */
355 return open (name, O_WRONLY | O_CREAT | O_TRUNC, PUBLIC_MODE);
358 /* Close a file. */
360 static int
361 pex_unix_close (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd)
363 return close (fd);
366 /* Report an error from a child process. We don't use stdio routines,
367 because we might be here due to a vfork call. */
369 static void
370 pex_child_error (struct pex_obj *obj, const char *executable,
371 const char *errmsg, int err)
373 int retval = 0;
374 #define writeerr(s) retval |= (write (STDERR_FILE_NO, s, strlen (s)) < 0)
375 writeerr (obj->pname);
376 writeerr (": error trying to exec '");
377 writeerr (executable);
378 writeerr ("': ");
379 writeerr (errmsg);
380 writeerr (": ");
381 writeerr (xstrerror (err));
382 writeerr ("\n");
383 #undef writeerr
384 /* Exit with -2 if the error output failed, too. */
385 _exit (retval == 0 ? -1 : -2);
388 /* Execute a child. */
390 extern char **environ;
392 #if defined(HAVE_SPAWNVE) && defined(HAVE_SPAWNVPE)
393 /* Implementation of pex->exec_child using the Cygwin spawn operation. */
395 /* Subroutine of pex_unix_exec_child. Move OLD_FD to a new file descriptor
396 to be stored in *PNEW_FD, save the flags in *PFLAGS, and arrange for the
397 saved copy to be close-on-exec. Move CHILD_FD into OLD_FD. If CHILD_FD
398 is -1, OLD_FD is to be closed. Return -1 on error. */
400 static int
401 save_and_install_fd(int *pnew_fd, int *pflags, int old_fd, int child_fd)
403 int new_fd, flags;
405 flags = fcntl (old_fd, F_GETFD);
407 /* If we could not retrieve the flags, then OLD_FD was not open. */
408 if (flags < 0)
410 new_fd = -1, flags = 0;
411 if (child_fd >= 0 && dup2 (child_fd, old_fd) < 0)
412 return -1;
414 /* If we wish to close OLD_FD, just mark it CLOEXEC. */
415 else if (child_fd == -1)
417 new_fd = old_fd;
418 if ((flags & FD_CLOEXEC) == 0 && fcntl (old_fd, F_SETFD, FD_CLOEXEC) < 0)
419 return -1;
421 /* Otherwise we need to save a copy of OLD_FD before installing CHILD_FD. */
422 else
424 #ifdef F_DUPFD_CLOEXEC
425 new_fd = fcntl (old_fd, F_DUPFD_CLOEXEC, 3);
426 if (new_fd < 0)
427 return -1;
428 #else
429 /* Prefer F_DUPFD over dup in order to avoid getting a new fd
430 in the range 0-2, right where a new stderr fd might get put. */
431 new_fd = fcntl (old_fd, F_DUPFD, 3);
432 if (new_fd < 0)
433 return -1;
434 if (fcntl (new_fd, F_SETFD, FD_CLOEXEC) < 0)
435 return -1;
436 #endif
437 if (dup2 (child_fd, old_fd) < 0)
438 return -1;
441 *pflags = flags;
442 if (pnew_fd)
443 *pnew_fd = new_fd;
444 else if (new_fd != old_fd)
445 abort ();
447 return 0;
450 /* Subroutine of pex_unix_exec_child. Move SAVE_FD back to OLD_FD
451 restoring FLAGS. If SAVE_FD < 0, OLD_FD is to be closed. */
453 static int
454 restore_fd(int old_fd, int save_fd, int flags)
456 /* For SAVE_FD < 0, all we have to do is restore the
457 "closed-ness" of the original. */
458 if (save_fd < 0)
459 return close (old_fd);
461 /* For SAVE_FD == OLD_FD, all we have to do is restore the
462 original setting of the CLOEXEC flag. */
463 if (save_fd == old_fd)
465 if (flags & FD_CLOEXEC)
466 return 0;
467 return fcntl (old_fd, F_SETFD, flags);
470 /* Otherwise we have to move the descriptor back, restore the flags,
471 and close the saved copy. */
472 #ifdef HAVE_DUP3
473 if (flags == FD_CLOEXEC)
475 if (dup3 (save_fd, old_fd, O_CLOEXEC) < 0)
476 return -1;
478 else
479 #endif
481 if (dup2 (save_fd, old_fd) < 0)
482 return -1;
483 if (flags != 0 && fcntl (old_fd, F_SETFD, flags) < 0)
484 return -1;
486 return close (save_fd);
489 static pid_t
490 pex_unix_exec_child (struct pex_obj *obj ATTRIBUTE_UNUSED,
491 int flags, const char *executable,
492 char * const * argv, char * const * env,
493 int in, int out, int errdes, int toclose,
494 const char **errmsg, int *err)
496 int fl_in = 0, fl_out = 0, fl_err = 0, fl_tc = 0;
497 int save_in = -1, save_out = -1, save_err = -1;
498 int max, retries;
499 pid_t pid;
501 if (flags & PEX_STDERR_TO_STDOUT)
502 errdes = out;
504 /* We need the three standard file descriptors to be set up as for
505 the child before we perform the spawn. The file descriptors for
506 the parent need to be moved and marked for close-on-exec. */
507 if (in != STDIN_FILE_NO
508 && save_and_install_fd (&save_in, &fl_in, STDIN_FILE_NO, in) < 0)
509 goto error_dup2;
510 if (out != STDOUT_FILE_NO
511 && save_and_install_fd (&save_out, &fl_out, STDOUT_FILE_NO, out) < 0)
512 goto error_dup2;
513 if (errdes != STDERR_FILE_NO
514 && save_and_install_fd (&save_err, &fl_err, STDERR_FILE_NO, errdes) < 0)
515 goto error_dup2;
516 if (toclose >= 0
517 && save_and_install_fd (NULL, &fl_tc, toclose, -1) < 0)
518 goto error_dup2;
520 /* Now that we've moved the file descriptors for the child into place,
521 close the originals. Be careful not to close any of the standard
522 file descriptors that we just set up. */
523 max = -1;
524 if (errdes >= 0)
525 max = STDERR_FILE_NO;
526 else if (out >= 0)
527 max = STDOUT_FILE_NO;
528 else if (in >= 0)
529 max = STDIN_FILE_NO;
530 if (in > max)
531 close (in);
532 if (out > max)
533 close (out);
534 if (errdes > max && errdes != out)
535 close (errdes);
537 /* If we were not given an environment, use the global environment. */
538 if (env == NULL)
539 env = environ;
541 /* Launch the program. If we get EAGAIN (normally out of pid's), try
542 again a few times with increasing backoff times. */
543 retries = 0;
544 while (1)
546 typedef const char * const *cc_cp;
548 if (flags & PEX_SEARCH)
549 pid = spawnvpe (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);
550 else
551 pid = spawnve (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);
553 if (pid > 0)
554 break;
556 *err = errno;
557 *errmsg = "spawn";
558 if (errno != EAGAIN || ++retries == 4)
559 return (pid_t) -1;
560 sleep (1 << retries);
563 /* Success. Restore the parent's file descriptors that we saved above. */
564 if (toclose >= 0
565 && restore_fd (toclose, toclose, fl_tc) < 0)
566 goto error_dup2;
567 if (in != STDIN_FILE_NO
568 && restore_fd (STDIN_FILE_NO, save_in, fl_in) < 0)
569 goto error_dup2;
570 if (out != STDOUT_FILE_NO
571 && restore_fd (STDOUT_FILE_NO, save_out, fl_out) < 0)
572 goto error_dup2;
573 if (errdes != STDERR_FILE_NO
574 && restore_fd (STDERR_FILE_NO, save_err, fl_err) < 0)
575 goto error_dup2;
577 return pid;
579 error_dup2:
580 *err = errno;
581 *errmsg = "dup2";
582 return (pid_t) -1;
585 #else
586 /* Implementation of pex->exec_child using standard vfork + exec. */
588 static pid_t
589 pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
590 char * const * argv, char * const * env,
591 int in, int out, int errdes,
592 int toclose, const char **errmsg, int *err)
594 pid_t pid;
596 /* We declare these to be volatile to avoid warnings from gcc about
597 them being clobbered by vfork. */
598 volatile int sleep_interval;
599 volatile int retries;
601 /* We vfork and then set environ in the child before calling execvp.
602 This clobbers the parent's environ so we need to restore it.
603 It would be nice to use one of the exec* functions that takes an
604 environment as a parameter, but that may have portability issues. */
605 char **save_environ = environ;
607 sleep_interval = 1;
608 pid = -1;
609 for (retries = 0; retries < 4; ++retries)
611 pid = vfork ();
612 if (pid >= 0)
613 break;
614 sleep (sleep_interval);
615 sleep_interval *= 2;
618 switch (pid)
620 case -1:
621 *err = errno;
622 *errmsg = VFORK_STRING;
623 return (pid_t) -1;
625 case 0:
626 /* Child process. */
627 if (in != STDIN_FILE_NO)
629 if (dup2 (in, STDIN_FILE_NO) < 0)
630 pex_child_error (obj, executable, "dup2", errno);
631 if (close (in) < 0)
632 pex_child_error (obj, executable, "close", errno);
634 if (out != STDOUT_FILE_NO)
636 if (dup2 (out, STDOUT_FILE_NO) < 0)
637 pex_child_error (obj, executable, "dup2", errno);
638 if (close (out) < 0)
639 pex_child_error (obj, executable, "close", errno);
641 if (errdes != STDERR_FILE_NO)
643 if (dup2 (errdes, STDERR_FILE_NO) < 0)
644 pex_child_error (obj, executable, "dup2", errno);
645 if (close (errdes) < 0)
646 pex_child_error (obj, executable, "close", errno);
648 if (toclose >= 0)
650 if (close (toclose) < 0)
651 pex_child_error (obj, executable, "close", errno);
653 if ((flags & PEX_STDERR_TO_STDOUT) != 0)
655 if (dup2 (STDOUT_FILE_NO, STDERR_FILE_NO) < 0)
656 pex_child_error (obj, executable, "dup2", errno);
659 if (env)
661 /* NOTE: In a standard vfork implementation this clobbers the
662 parent's copy of environ "too" (in reality there's only one copy).
663 This is ok as we restore it below. */
664 environ = (char**) env;
667 if ((flags & PEX_SEARCH) != 0)
669 execvp (executable, to_ptr32 (argv));
670 pex_child_error (obj, executable, "execvp", errno);
672 else
674 execv (executable, to_ptr32 (argv));
675 pex_child_error (obj, executable, "execv", errno);
678 /* NOTREACHED */
679 return (pid_t) -1;
681 default:
682 /* Parent process. */
684 /* Restore environ.
685 Note that the parent either doesn't run until the child execs/exits
686 (standard vfork behaviour), or if it does run then vfork is behaving
687 more like fork. In either case we needn't worry about clobbering
688 the child's copy of environ. */
689 environ = save_environ;
691 if (in != STDIN_FILE_NO)
693 if (close (in) < 0)
695 *err = errno;
696 *errmsg = "close";
697 return (pid_t) -1;
700 if (out != STDOUT_FILE_NO)
702 if (close (out) < 0)
704 *err = errno;
705 *errmsg = "close";
706 return (pid_t) -1;
709 if (errdes != STDERR_FILE_NO)
711 if (close (errdes) < 0)
713 *err = errno;
714 *errmsg = "close";
715 return (pid_t) -1;
719 return pid;
722 #endif /* SPAWN */
724 /* Wait for a child process to complete. */
726 static int
727 pex_unix_wait (struct pex_obj *obj, pid_t pid, int *status,
728 struct pex_time *time, int done, const char **errmsg,
729 int *err)
731 /* If we are cleaning up when the caller didn't retrieve process
732 status for some reason, encourage the process to go away. */
733 if (done)
734 kill (pid, SIGTERM);
736 if (pex_wait (obj, pid, status, time) < 0)
738 *err = errno;
739 *errmsg = "wait";
740 return -1;
743 return 0;
746 /* Create a pipe. */
748 static int
749 pex_unix_pipe (struct pex_obj *obj ATTRIBUTE_UNUSED, int *p,
750 int binary ATTRIBUTE_UNUSED)
752 return pipe (p);
755 /* Get a FILE pointer to read from a file descriptor. */
757 static FILE *
758 pex_unix_fdopenr (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
759 int binary ATTRIBUTE_UNUSED)
761 return fdopen (fd, "r");
764 static FILE *
765 pex_unix_fdopenw (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
766 int binary ATTRIBUTE_UNUSED)
768 if (fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
769 return NULL;
770 return fdopen (fd, "w");
773 static void
774 pex_unix_cleanup (struct pex_obj *obj ATTRIBUTE_UNUSED)
776 #if !defined (HAVE_WAIT4) && !defined (HAVE_WAITPID)
777 while (obj->sysdep != NULL)
779 struct status_list *this;
780 struct status_list *next;
782 this = (struct status_list *) obj->sysdep;
783 next = this->next;
784 free (this);
785 obj->sysdep = (void *) next;
787 #endif