winsup/cygwin/wait.cc

   1 /* wait.cc: Posix wait routines.
   2
   3 This file is part of Cygwin.
   4
   5 This software is a copyrighted work licensed under the terms of the
   6 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   7 details. */
   8
   9 #include "winsup.h"
  10 #include <sys/wait.h>
  11 #include "sigproc.h"
  12 #include "thread.h"
  13 #include "cygtls.h"
  14 #include "cygwait.h"
  15
  16 /* This is called _wait and not wait because the real wait is defined
  17    in libc/syscalls/syswait.c.  It calls us.  */
  18
  19 extern "C" pid_t
  20 wait (int *status)
  21 {
  22   return wait4 (-1, status, 0, NULL);
  23 }
  24
  25 extern "C" pid_t
  26 waitpid (pid_t intpid, int *status, int options)
  27 {
  28   return wait4 (intpid, status, options, NULL);
  29 }
  30
  31 extern "C" pid_t
  32 wait3 (int *status, int options, struct rusage *r)
  33 {
  34   return wait4 (-1, status, options, r);
  35 }
  36
  37 /* Wait for any child to complete.
  38  * Note: this is not thread safe.  Use of wait in multiple threads will
  39  * not work correctly.
  40  */
  41
  42 extern "C" pid_t
  43 wait4 (int intpid, int *status, int options, struct rusage *r)
  44 {
  45   int res;
  46   HANDLE waitfor;
  47   waitq *w = &_my_tls.wq;
  48
  49   pthread_testcancel ();
  50
  51   while (1)
  52     {
  53       sig_dispatch_pending ();
  54       if (options & ~(WNOHANG | WUNTRACED | WCONTINUED))
  55         {
  56           set_errno (EINVAL);
  57           res = -1;
  58           break;
  59         }
  60
  61       if (r)
  62         memset (r, 0, sizeof (*r));
  63
  64       w->pid = intpid;
  65       w->options = options;
  66       w->rusage = r;
  67       sigproc_printf ("calling proc_subproc, pid %d, options %d",
  68                       w->pid, w->options);
  69       if (!proc_subproc (PROC_WAIT, (uintptr_t) w))
  70         {
  71           set_errno (ENOSYS);
  72           paranoid_printf ("proc_subproc returned 0");
  73           res = -1;
  74           break;
  75         }
  76
  77       if ((waitfor = w->ev) == NULL)
  78         goto nochildren;
  79
  80       res = cygwait (waitfor, cw_infinite, cw_cancel | cw_cancel_self);
  81
  82       sigproc_printf ("%d = cygwait (...)", res);
  83
  84       if (w->ev == NULL)
  85         {
  86         nochildren:
  87           /* found no children */
  88           set_errno (ECHILD);
  89           res = -1;
  90           break;
  91         }
  92
  93       if (w->status == -1)
  94         {
  95           if (_my_tls.call_signal_handler ())
  96             continue;
  97           set_sig_errno (EINTR);
  98           res = -1;
  99         }
 100       else if (res != WAIT_OBJECT_0)
 101         {
 102           set_errno (EINVAL);
 103           res = -1;
 104         }
 105       else if ((res = w->pid) != 0 && status)
 106         *status = w->status;
 107       break;
 108     }
 109
 110   syscall_printf ("%R = wait4(%d, %y, %d, %p)", res, intpid, w->status, options, r);
 111   w->status = -1;
 112   return res;
 113 }