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[PATCH 1/2] stat-macros: Enhance to provide block-related information.


From: James Youngman
Subject: [PATCH 1/2] stat-macros: Enhance to provide block-related information.
Date: Wed, 8 Jun 2011 00:38:02 +0100

* lib/stat-macros.h: Insert part of coreutils' system.h, which
defines DEV_BSIZE, ST_BLKSIZE, ST_NBLOCKS and ST_NBLOCKSIZE.
* modules/stat-macros: Depend on sys_stat (because now
stat-macros.h includes sys/stat.h) and stdint (because we need
SIZE_MAX).  Since the file is now substantially composed of an
extract from coreutils system.h, which findutils shares, change
the maintainer to James Youngman, Jim Meyering.
* m4/stat-macros.m4: Check for sys/param.h.
* modules/stat-macros-tests: New test module for stat-macros.
* tests/test-stat-macros.c: New test, verifies very basic
behaviour of stat-macros.h.
---
 ChangeLog                 |   15 ++++++
 lib/stat-macros.h         |  116 ++++++++++++++++++++++++++++++++++++++++++++-
 m4/stat-macros.m4         |    3 +-
 modules/stat-macros       |    4 +-
 modules/stat-macros-tests |   14 +++++
 tests/test-stat-macros.c  |  115 ++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 264 insertions(+), 3 deletions(-)
 create mode 100644 modules/stat-macros-tests
 create mode 100644 tests/test-stat-macros.c

diff --git a/ChangeLog b/ChangeLog
index 62b99f3..c7ddc06 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2011-06-06  James Youngman  <address@hidden>
+
+       stat-macros: Enhance to provide block-related information.
+       * lib/stat-macros.h: Insert part of coreutils' system.h, which
+       defines DEV_BSIZE, ST_BLKSIZE, ST_NBLOCKS and ST_NBLOCKSIZE.
+       * modules/stat-macros: Depend on sys_stat (because now
+       stat-macros.h includes sys/stat.h) and stdint (because we need
+       SIZE_MAX).  Since the file is now substantially composed of an
+       extract from coreutils system.h, which findutils shares, change
+       the maintainer to James Youngman, Jim Meyering.
+       * m4/stat-macros.m4: Check for sys/param.h.
+       * modules/stat-macros-tests: New test module for stat-macros.
+       * tests/test-stat-macros.c: New test, verifies very basic
+       behaviour of stat-macros.h.
+
 2011-06-05  Bruno Haible  <address@hidden>
 
        acl: Fix test failure on AIX 7.
diff --git a/lib/stat-macros.h b/lib/stat-macros.h
index 690216c..c196406 100644
--- a/lib/stat-macros.h
+++ b/lib/stat-macros.h
@@ -1,3 +1,117 @@
+/* macros useful in interpreting values in struct stat.
+   Copyright (C) 1989, 1991-2011 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 of the License, 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, see <http://www.gnu.org/licenses/>.  */
+/*
+   Macros defined by this file (s is an rvalue of type struct stat):
+   CHMOD_MODE_BITS: All the mode bits that can be affected by chmod.
+   DEV_BSIZE:       The device blocksize.  But use ST_NBLOCKSIZE instead.
+   ST_BLKSIZE(s):   Preferred (in the sense of best performance) I/O blocksize
+                    for the file, in bytes.
+   ST_NBLOCKS(s):   Number of blocks in the file, including indirect blocks.
+   ST_NBLOCKSIZE:   Size of blocks used when calculating ST_NBLOCKS.
+ */
+#ifndef STAT_MACROS_H
+# define STAT_MACROS_H
+
+# include <stdint.h>           /* We need to know SIZE_MAX */
+# include <sys/stat.h>
+# if HAVE_SYS_PARAM_H
+#  include <sys/param.h>
+# endif
+
+
+
 /* All the mode bits that can be affected by chmod.  */
-#define CHMOD_MODE_BITS \
+# define CHMOD_MODE_BITS \
   (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
+
+
+/* Much of the remainder of this file is not indented consistently
+   with the above, in order to make it easier to see that the text
+   is almost identical to part of the system.h header in coreutils.
+*/
+/* Get or fake the disk device blocksize.
+   Usually defined by sys/param.h (if at all).  */
+#if !defined DEV_BSIZE && defined BSIZE
+# define DEV_BSIZE BSIZE
+#endif
+#if !defined DEV_BSIZE && defined BBSIZE /* SGI sys/param.h */
+# define DEV_BSIZE BBSIZE
+#endif
+#ifndef DEV_BSIZE
+# define DEV_BSIZE 4096
+#endif
+
+/* Extract or fake data from a `struct stat'.
+   ST_BLKSIZE: Preferred I/O blocksize for the file, in bytes.
+   ST_NBLOCKS: Number of blocks in the file, including indirect blocks.
+   ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS.  */
+#ifndef HAVE_STRUCT_STAT_ST_BLOCKS
+# define ST_BLKSIZE(statbuf) DEV_BSIZE
+/* coreutils' fileblocks.c also uses BSIZE.  */
+# if defined _POSIX_SOURCE || !defined BSIZE 
+#  define ST_NBLOCKS(statbuf) \
+  ((statbuf).st_size / ST_NBLOCKSIZE + ((statbuf).st_size % ST_NBLOCKSIZE != 
0))
+# else /* !_POSIX_SOURCE && BSIZE */
+#  define ST_NBLOCKS(statbuf) \
+  (S_ISREG ((statbuf).st_mode) \
+   || S_ISDIR ((statbuf).st_mode) \
+   ? st_blocks ((statbuf).st_size) : 0)
+# endif /* !_POSIX_SOURCE && BSIZE */
+#else /* HAVE_STRUCT_STAT_ST_BLOCKS */
+/* Some systems, like Sequents, return st_blksize of 0 on pipes.
+   Also, when running `rsh hpux11-system cat any-file', cat would
+   determine that the output stream had an st_blksize of 2147421096.
+   Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS
+   on 64-bit hosts.  Somewhat arbitrarily, limit the `optimal' block
+   size to SIZE_MAX / 8 + 1.  (Dividing SIZE_MAX by only 4 wouldn't
+   suffice, since "cat" sometimes multiplies the result by 4.)  If
+   anyone knows of a system for which this limit is too small, please
+   report it as a bug in this code.  */
+# define ST_BLKSIZE(statbuf) ((0 < (statbuf).st_blksize \
+                               && (statbuf).st_blksize <= SIZE_MAX / 8 + 1) \
+                              ? (statbuf).st_blksize : DEV_BSIZE)
+# if defined hpux || defined __hpux__ || defined __hpux
+/* HP-UX counts st_blocks in 1024-byte units.
+   This loses when mixing HP-UX and BSD file systems with NFS.  */
+#  define ST_NBLOCKSIZE 1024
+# else /* !hpux */
+#  if defined _AIX && defined _I386
+/* AIX PS/2 counts st_blocks in 4K units.  */
+#   define ST_NBLOCKSIZE (4 * 1024)
+#  else /* not AIX PS/2 */
+#   if defined _CRAY
+#    define ST_NBLOCKS(statbuf) \
+  (S_ISREG ((statbuf).st_mode) \
+   || S_ISDIR ((statbuf).st_mode) \
+   ? (statbuf).st_blocks * ST_BLKSIZE (statbuf) / ST_NBLOCKSIZE : 0)
+#   endif /* _CRAY */
+#  endif /* not AIX PS/2 */
+# endif /* !hpux */
+#endif /* HAVE_STRUCT_STAT_ST_BLOCKS */
+
+#ifndef ST_NBLOCKS
+# define ST_NBLOCKS(statbuf) ((statbuf).st_blocks)
+#endif
+
+#ifndef ST_NBLOCKSIZE
+# ifdef S_BLKSIZE
+#  define ST_NBLOCKSIZE S_BLKSIZE
+# else
+#  define ST_NBLOCKSIZE 512
+# endif
+#endif
+
+#endif /* STAT_MACROS_H */
diff --git a/m4/stat-macros.m4 b/m4/stat-macros.m4
index cd86c09..c575f68 100644
--- a/m4/stat-macros.m4
+++ b/m4/stat-macros.m4
@@ -1,4 +1,4 @@
-#serial 3
+#serial 4
 
 # Copyright (C) 2005-2006, 2009-2011 Free Software Foundation, Inc.
 #
@@ -9,4 +9,5 @@
 AC_DEFUN([gl_STAT_MACROS],
 [
   AC_REQUIRE([AC_HEADER_STAT])
+  AC_CHECK_HEADERS([sys/param.h])
 ])
diff --git a/modules/stat-macros b/modules/stat-macros
index d9a331c..68fa6dc 100644
--- a/modules/stat-macros
+++ b/modules/stat-macros
@@ -5,6 +5,8 @@ Files:
 lib/stat-macros.h
 
 Depends-on:
+sys_stat
+stdint
 
 configure.ac:
 
@@ -17,4 +19,4 @@ License:
 GPL
 
 Maintainer:
-all
+James Youngman, Jim Meyering
diff --git a/modules/stat-macros-tests b/modules/stat-macros-tests
new file mode 100644
index 0000000..d56481c
--- /dev/null
+++ b/modules/stat-macros-tests
@@ -0,0 +1,14 @@
+Files:
+tests/test-stat-macros.c
+
+Depends-on:
+fcntl
+open
+stat
+unistd
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-stat-macros
+check_PROGRAMS += test-stat-macros
diff --git a/tests/test-stat-macros.c b/tests/test-stat-macros.c
new file mode 100644
index 0000000..b312e14
--- /dev/null
+++ b/tests/test-stat-macros.c
@@ -0,0 +1,115 @@
+/* Tests of stat-macros.h.
+   Copyright (C) 2011 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 of the License, 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, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+#include "stat-macros.h"
+
+#include <stdio.h>             /* perror */
+#include <fcntl.h>             /* open */
+#include <unistd.h>            /* unlink, close */
+
+/*
+ST_NBLOCKS may be 0
+
+: test ST_NBLOCKSIZE for nonzeroness
+: ST_NBLOCKS(s) by creating a file.
+: ST_BLKSIZE(s) by creating a file.
+*/
+
+#include "macros.h"
+
+
+/* Create a test file containing more than one block, 
+   and return nonzero if successful. */
+static int
+create_test_file (const char *name)
+{
+  int retval = 0;
+  char buf[ST_NBLOCKSIZE];     /* contents are irrelevant */
+  int fd = open (name, O_CREAT|O_WRONLY, 0700);
+  if (fd >= 0)
+    {
+      if (write (fd, buf, ST_NBLOCKSIZE) >= 0)
+       {
+         if (write (fd, buf, ST_NBLOCKSIZE) >= 0)
+           retval = 1;
+         else
+           perror (name);
+       }
+      else
+       {
+         perror (name);
+       }
+      close (fd);
+    }
+  else
+    {
+      perror (name);
+    }
+  return retval;
+}
+
+
+static void
+test_nblocksize (void)
+{
+  ASSERT (ST_NBLOCKSIZE > 0);
+}
+
+static void
+test_nblocks (const struct stat *p)
+{
+  ASSERT (ST_NBLOCKS (*p) > 0);
+}
+
+
+static void
+test_blksize (const struct stat *p)
+{
+  ASSERT (ST_BLKSIZE (*p) > 0);
+}
+
+
+int main (int argc, char *argv[])
+{
+  const char *test_file_name = "test-statmacros.txt";
+  int result = 0;
+
+  test_nblocksize ();
+  if (create_test_file (test_file_name))
+    {
+      struct stat st;
+      if (0 == stat (test_file_name, &st))
+       {
+         ASSERT (st.st_size > 1);
+         test_nblocks (&st);
+         test_blksize (&st);
+       }
+      else
+       {
+         perror (test_file_name);
+         result = 1;
+       }
+    }
+  else
+    {
+      result = 1;
+    }
+  /* Even if create_test_file failed for some reason, the test
+     file may still exist. */
+  (void) unlink (test_file_name);
+  return result;
+}
-- 
1.7.2.5




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