Add alternate implementation of waitpid() for systems that have wait4 but

not wait3, in particular Amdahl's SVR2-based UTS 2.1.2.  The code comes
from apache, but I contributed it to apache in the first place.

diff --git a/configure.in b/configure.in
index 79aab77..25bf768 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -49,7 +49,7 @@ fi
 
 AC_FUNC_MEMCMP
 AC_FUNC_UTIME_NULL
-AC_CHECK_FUNCS(waitpid getcwd strdup strerror chown chmod mknod)
+AC_CHECK_FUNCS(waitpid wait4 getcwd strdup strerror chown chmod mknod)
 AC_CHECK_FUNCS(fchmod fstat strchr readlink link utime utimes strftime)
 AC_CHECK_FUNCS(memmove getopt_long lchown vsnprintf snprintf setsid glob strpbrk)
 AC_CHECK_FUNCS(strlcat strlcpy)

diff --git a/lib/compat.c b/lib/compat.c
index f491348..9b411cd 100644 (file)
--- a/lib/compat.c
+++ b/lib/compat.c
@@ -46,7 +46,25 @@
 #ifndef HAVE_WAITPID
  pid_t waitpid(pid_t pid, int *statptr, int options)
 {
+#ifdef HAVE_WAIT4
        return wait4(pid, statptr, options, NULL);
+#else
+       /* If wait4 is also not available, try wait3 for SVR3 variants */
+       /* Less ideal because can't actually request a specific pid */
+       /* At least the WNOHANG option is supported */
+       /* Code borrowed from apache fragment written by dwd@bell-labs.com */
+       int tmp_pid, dummystat;;
+       if (kill(pid, 0) == -1) {
+               errno = ECHILD;
+               return -1;
+       }
+       if (statptr == NULL)
+               statptr = &dummystat;
+       while (((tmp_pid = wait3(statptr, options, 0)) != pid) &&
+                   (tmp_pid != -1) && (tmp_pid != 0) && (pid != -1))
+           ;
+       return tmp_pid;
+#endif
 }
 #endif