Restore after an accidental remove

lib/waitpid.c

@@ -0,0 +1,75 @@
+/* Emulate waitpid on systems that just have wait.
+   Copyright 1994, 1995, 1998, 1999, 2007 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING.
+   If not, write to the Free Software Foundation, 
+   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#ifndef errno
+extern int errno;
+#endif
+
+#define WAITPID_CHILDREN 8
+static pid_t waited_pid[WAITPID_CHILDREN];
+static int waited_status[WAITPID_CHILDREN];
+
+pid_t
+waitpid (pid_t pid, int *stat_loc, int options)
+{
+  int i;
+  pid_t p;
+
+  if (!options && (pid == -1 || 0 < pid))
+    {
+      /* If we have already waited for this child, return it immediately.  */
+      for (i = 0;  i < WAITPID_CHILDREN;  i++)
+	{
+	  p = waited_pid[i];
+	  if (p && (p == pid || pid == -1))
+	    {
+	      waited_pid[i] = 0;
+	      goto success;
+	    }
+	}
+
+      /* The child has not returned yet; wait for it, accumulating status.  */
+      for (i = 0;  i < WAITPID_CHILDREN;  i++)
+	if (! waited_pid[i])
+	  {
+	    p = wait (&waited_status[i]);
+	    if (p < 0)
+	      return p;
+	    if (p == pid || pid == -1)
+	      goto success;
+	    waited_pid[i] = p;
+	  }
+    }
+
+  /* We cannot emulate this wait call, e.g. because of too many children.  */
+  errno = EINVAL;
+  return -1;
+
+success:
+  if (stat_loc)
+    *stat_loc = waited_status[i];
+  return p;
+}