[PATCH] New modules nproc, pthread.

[Paul Eggert]

This patch is to add multithread support for coreutils.  The code was
written by Glen Lenker, who has filed papers with the GNU project.
The pthread emulation (for platforms that lack pthreads) is very minimal,
just enough for coreutils to get by.

* MODULES.html.sh: Add pthread, nproc.
* lib/nproc.c: New file.
* lib/nproc.h: New file.
* lib/pthread.in.h: New file.
* m4/pthread.m4: New file.
* modules/nproc: New file.
* modules/pthread: New file.
---
 ChangeLog        |   12 ++++++++++++
 MODULES.html.sh  |    4 +++-
 lib/nproc.c      |   38 ++++++++++++++++++++++++++++++++++++++
 lib/nproc.h      |   21 +++++++++++++++++++++
 lib/pthread.in.h |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 m4/pthread.m4    |   27 +++++++++++++++++++++++++++
 modules/nproc    |   23 +++++++++++++++++++++++
 modules/pthread  |   29 +++++++++++++++++++++++++++++
 8 files changed, 199 insertions(+), 1 deletions(-)
 create mode 100644 lib/nproc.c
 create mode 100644 lib/nproc.h
 create mode 100644 lib/pthread.in.h
 create mode 100644 m4/pthread.m4
 create mode 100644 modules/nproc
 create mode 100644 modules/pthread

diff --git a/ChangeLog b/ChangeLog
index 1b9cc0c..1698422 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2009-03-25  Paul Eggert  <address@hidden>
+
+       New modules nproc, pthread, contributed by Glen Lenker.
+
+       * MODULES.html.sh: Add pthread, nproc.
+       * lib/nproc.c: New file.
+       * lib/nproc.h: New file.
+       * lib/pthread.in.h: New file.
+       * m4/pthread.m4: New file.
+       * modules/nproc: New file.
+       * modules/pthread: New file.
+
 2009-03-24  Simon Josefsson  <address@hidden>
 
        * modules/unicase/locale-language-tests (test_locale_language_LDADD):
diff --git a/MODULES.html.sh b/MODULES.html.sh
index 6145234..a5efaeb 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright (C) 2002-2008 Free Software Foundation, Inc.
+# Copyright (C) 2002-2009 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
@@ -2301,6 +2301,7 @@ func_all_modules ()
   func_module posix_spawn-internal
   func_module posix_spawnp
   func_module printf-posix
+  func_module pthread
   func_module readlink
   func_module realloc-posix
   func_module recv
@@ -3101,6 +3102,7 @@ func_all_modules ()
   func_module getloadavg
   func_module getpagesize
   func_module getusershell
+  func_module nproc
   func_module physmem
   func_module posixver
   func_module progname
diff --git a/lib/nproc.c b/lib/nproc.c
new file mode 100644
index 0000000..9a6e23a
--- /dev/null
+++ b/lib/nproc.c
@@ -0,0 +1,38 @@
+/* Detect the number of processors.
+
+   Copyright (C) 2009 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 2, 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; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Written by Glen Lenker.  */
+
+#include <config.h>
+#include "nproc.h"
+
+#include <unistd.h>
+
+/* Return the total number of processors.  The result is guaranteed to
+   be at least 1.  */
+unsigned long int
+num_processors (void)
+{
+#ifdef _SC_NPROCESSORS_ONLN
+  long int nprocs = sysconf (_SC_NPROCESSORS_ONLN);
+  if (0 < nprocs)
+    return nprocs;
+#endif
+
+  return 1;
+}
diff --git a/lib/nproc.h b/lib/nproc.h
new file mode 100644
index 0000000..fe5b57e
--- /dev/null
+++ b/lib/nproc.h
@@ -0,0 +1,21 @@
+/* Detect the number of processors.
+
+   Copyright (C) 2009 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 2, 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; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Written by Glen Lenker.  */
+
+unsigned long int num_processors (void);
diff --git a/lib/pthread.in.h b/lib/pthread.in.h
new file mode 100644
index 0000000..ae91ed2
--- /dev/null
+++ b/lib/pthread.in.h
@@ -0,0 +1,46 @@
+/* Implement a trivial subset of the pthreads library.
+
+   Copyright (C) 2009 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 2, 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; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Written by Glen Lenker.  */
+
+#ifndef PTHREAD_H_
+# define PTHREAD_H_
+
+# include <errno.h>
+# include <stdlib.h>
+
+typedef int pthread_t;
+typedef int pthread_attr_t;
+
+static int
+pthread_create (pthread_t *restrict thread,
+               const pthread_attr_t *restrict attr,
+               void *(*start_routine)(void*), void *restrict arg)
+{
+  errno = EAGAIN;
+  return -1;
+}
+
+static int
+pthread_join (pthread_t thread, void **value_ptr)
+{
+  abort ();
+  return -1;
+}
+
+#endif /* PTHREAD_H_ */
diff --git a/m4/pthread.m4 b/m4/pthread.m4
new file mode 100644
index 0000000..2a38307
--- /dev/null
+++ b/m4/pthread.m4
@@ -0,0 +1,27 @@
+# pthread.m4
+dnl Copyright (C) 2009 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_PTHREAD_CHECK],
+  [AC_CHECK_HEADERS_ONCE([pthread.h])
+
+   LIB_PTHREAD=
+   PTHREAD_H=
+   if test "$ac_cv_header_pthread_h" = yes; then
+     gl_saved_libs=$LIBS
+     AC_SEARCH_LIBS([pthread_create], [pthread],
+       [if test "$ac_cv_search_pthread_create" != "none required"; then
+         LIB_PTHREAD="$ac_cv_search_pthread_create"
+       fi])
+     LIBS="$gl_saved_libs"
+   else
+     PTHREAD_H='pthread.h'
+   fi
+
+   AC_SUBST([LIB_PTHREAD])
+   AC_SUBST([PTHREAD_H])
+
+   AC_REQUIRE([AC_C_RESTRICT])
+])
diff --git a/modules/nproc b/modules/nproc
new file mode 100644
index 0000000..9a98615
--- /dev/null
+++ b/modules/nproc
@@ -0,0 +1,23 @@
+Description:
+Detect the number of processors
+
+Files:
+lib/nproc.h
+lib/nproc.c
+
+Depends-on:
+unistd
+
+configure.ac:
+AC_LIBOBJ([nproc])
+
+Makefile.am:
+
+Include:
+#include "nproc.h"
+
+License:
+GPL
+
+Maintainer:
+Glen Lenker and Paul Eggert
diff --git a/modules/pthread b/modules/pthread
new file mode 100644
index 0000000..b79af69
--- /dev/null
+++ b/modules/pthread
@@ -0,0 +1,29 @@
+Description:
+Implement a trivial subset of the pthreads library.
+
+Files:
+lib/pthread.in.h
+m4/pthread.m4
+
+Depends-on:
+
+configure.ac:
+gl_PTHREAD_CHECK
+
+Makefile.am:
+BUILT_SOURCES += $(PTHREAD_H)
+
+# We need the following in order to create <pthread.h> when the system
+# doesn't have one that works with the given compiler.
+pthread.h: pthread.in.h
+       ln -f pthread.in.h $@ || cp pthread.in.h $@
+MOSTLYCLEANFILES += pthread.h
+
+Include:
+#include <pthread.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Glen Lenker and Paul Eggert
-- 
1.6.2.1