Hi,
There is a pread module, but no pwrite. This is a mostly mechanical
patch, copying the pread bits and s/read/write/ and copying pwrite.c
from glibc.
2010-05-05 Peter O'Gorman <po...@thewrittenword.com>
New module pwrite
* doc/posix-functions/pread.texi: Mention gnulib module.
* doc/posix-functions/pwrite.texi: Likewise.
* MODULES.html.sh: Add pwrite.
* lib/unistd.in.h: Likewise.
* m4/unistd_h.m4: Likewise.
* modules/unistd: Likewise.
* tests/test-unistd-c++.cc: Likewise.
* lib/pwrite.c: Likewise.
* m4/pwrite.m4: Likewise.
* modules/pwrite: Likewise.
* modules/pwrite-tests: Likewise.
* tests/test-pwrite.c: Likewise.
* tests/test-pwrite.core: Likewise.
* tests/test-pwrite.sh: Likewise.
Peter
--
Peter O'Gorman
po...@thewrittenword.com
>From cd7b12cc394f80b07dc86b5516e2ec5ee934efd8 Mon Sep 17 00:00:00 2001
From: Peter O'Gorman <po...@thor.il.thewrittenword.com>
Date: Wed, 5 May 2010 02:55:41 +0000
Subject: [PATCH] New module pwrite
* doc/posix-functions/pread.texi: Mention gnulib module.
* doc/posix-functions/pwrite.texi: Likewise.
* MODULES.html.sh: Add pwrite.
* lib/unistd.in.h: Likewise.
* m4/unistd_h.m4: Likewise.
* modules/unistd: Likewise.
* tests/test-unistd-c++.cc: Likewise.
* lib/pwrite.c: Likewise.
* m4/pwrite.m4: Likewise.
* modules/pwrite: Likewise.
* modules/pwrite-tests: Likewise.
* tests/test-pwrite.c: Likewise.
* tests/test-pwrite.core: Likewise.
* tests/test-pwrite.sh: Likewise.
---
ChangeLog | 18 +++++++++
MODULES.html.sh | 2 +
doc/posix-functions/pread.texi | 4 +-
doc/posix-functions/pwrite.texi | 4 +-
lib/pwrite.c | 64 +++++++++++++++++++++++++++++++
lib/unistd.in.h | 36 +++++++++++++++++-
m4/pwrite.m4 | 18 +++++++++
m4/unistd_h.m4 | 8 +++-
modules/pwrite | 24 ++++++++++++
modules/pwrite-tests | 14 +++++++
modules/unistd | 3 +
tests/test-pwrite.c | 80 +++++++++++++++++++++++++++++++++++++++
tests/test-pwrite.sh | 7 +++
tests/test-unistd-c++.cc | 5 ++
14 files changed, 280 insertions(+), 7 deletions(-)
create mode 100644 lib/pwrite.c
create mode 100644 m4/pwrite.m4
create mode 100644 modules/pwrite
create mode 100644 modules/pwrite-tests
create mode 100644 tests/test-pwrite.c
create mode 100755 tests/test-pwrite.sh
diff --git a/ChangeLog b/ChangeLog
index d737948..c3c6e9d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+2010-05-05 Peter O'Gorman <po...@thewrittenword.com>
+
+ New module pwrite
+ * doc/posix-functions/pread.texi: Mention gnulib module.
+ * doc/posix-functions/pwrite.texi: Likewise.
+ * MODULES.html.sh: Add pwrite.
+ * lib/unistd.in.h: Likewise.
+ * m4/unistd_h.m4: Likewise.
+ * modules/unistd: Likewise.
+ * tests/test-unistd-c++.cc: Likewise.
+ * lib/pwrite.c: Likewise.
+ * m4/pwrite.m4: Likewise.
+ * modules/pwrite: Likewise.
+ * modules/pwrite-tests: Likewise.
+ * tests/test-pwrite.c: Likewise.
+ * tests/test-pwrite.core: Likewise.
+ * tests/test-pwrite.sh: Likewise.
+
2010-05-04 Eric Blake <ebl...@redhat.com>
docs: update cygwin progress
diff --git a/MODULES.html.sh b/MODULES.html.sh
index b0fbe39..822ac83 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -846,6 +846,7 @@ pow
powf
powl
pread
+pwrite
printf
pselect
psiginfo
@@ -1346,6 +1347,7 @@ index
makecontext
mktemp
pread
+pwrite
pthread_attr_getstackaddr
pthread_attr_setstackaddr
rindex
diff --git a/doc/posix-functions/pread.texi b/doc/posix-functions/pread.texi
index a11e36e..651256d 100644
--- a/doc/posix-functions/pread.texi
+++ b/doc/posix-functions/pread.texi
@@ -4,13 +4,13 @@
POSIX specification:
@url{http://www.opengroup.org/onlinepubs/9699919799/functions/pread.html}
-Gnulib module: ---
+Gnulib module: pread
Portability problems fixed by Gnulib:
@itemize
@item
This function is missing on some platforms:
-mingw, BeOS.
+mingw, BeOS, HP-UX 10.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/doc/posix-functions/pwrite.texi b/doc/posix-functions/pwrite.texi
index d164503..735c897 100644
--- a/doc/posix-functions/pwrite.texi
+++ b/doc/posix-functions/pwrite.texi
@@ -4,7 +4,7 @@
POSIX specification:
@url{http://www.opengroup.org/onlinepubs/9699919799/functions/pwrite.html}
-Gnulib module: ---
+Gnulib module: pwrite
Portability problems fixed by Gnulib:
@itemize
@@ -14,5 +14,5 @@ Portability problems not fixed by Gnulib:
@itemize
@item
This function is missing on some platforms:
-mingw, BeOS.
+mingw, BeOS, HP-UX 10.
@end itemize
diff --git a/lib/pwrite.c b/lib/pwrite.c
new file mode 100644
index 0000000..f9c1498
--- /dev/null
+++ b/lib/pwrite.c
@@ -0,0 +1,64 @@
+/* Write block to given position in file without changing file
+ * pointer.
+ POSIX version.
+ Copyright (C) 1997, 1998, 1999, 2002 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drep...@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+#include <config.h>
+
+#include <errno.h>
+#include <unistd.h>
+
+#define __libc_lseek(f,o,w) lseek (f, o, w)
+#define __set_errno(Val) errno = (Val)
+#define __libc_write(f,b,n) write (f, b, n)
+
+/* Note: This implementation of pwrite is not multithread-safe. */
+
+ssize_t
+pwrite (int fd, const void *buf, size_t nbyte, off_t offset)
+{
+ /* Since we must not change the file pointer preserve the value so that
+ we can restore it later. */
+ int save_errno;
+ ssize_t result;
+ off_t old_offset = __libc_lseek (fd, 0, SEEK_CUR);
+ if (old_offset == (off_t) -1)
+ return -1;
+
+ /* Set to wanted position. */
+ if (__libc_lseek (fd, offset, SEEK_SET) == (off_t) -1)
+ return -1;
+
+ /* Write out the data. */
+ result = __libc_write (fd, buf, nbyte);
+
+ /* Now we have to restore the position. If this fails we have to
+ return this as an error. But if the writing also failed we
+ return this error. */
+ save_errno = errno;
+ if (__libc_lseek (fd, old_offset, SEEK_SET) == (off_t) -1)
+ {
+ if (result == -1)
+ __set_errno (save_errno);
+ return -1;
+ }
+ __set_errno (save_errno);
+
+ return result;
+}
diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index b1f0743..49f6bad 100644
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -86,7 +86,7 @@
#endif
#if (@GNULIB_WRITE@ || @GNULIB_READLINK@ || @GNULIB_READLINKAT@ \
- || @GNULIB_PREAD@ || defined GNULIB_POSIXCHECK)
+ || @GNULIB_PREAD@ || @GNULIB_PWRITE@ || defined GNULIB_POSIXCHECK)
/* Get ssize_t. */
# include <sys/types.h>
#endif
@@ -1016,6 +1016,40 @@ _GL_WARN_ON_USE (pread, "pread is unportable - "
#endif
+#if @GNULIB_PWRITE@
+/* Write at most BUFSIZE bytes from BUF into FD, starting at OFFSET.
+ Return the number of bytes written if successful, otherwise
+ set errno and return -1. 0 indicates nothing written. See the
+ POSIX:2001 specification
+ <http://www.opengroup.org/susv3xsh/pwrite.html>. */
+# if @REPLACE_PWRITE@
+# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+# define pwrite rpl_pwrite
+# endif
+_GL_FUNCDECL_RPL (pwrite, ssize_t,
+ (int fd, const void *buf, size_t bufsize, off_t offset)
+ _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (pwrite, ssize_t,
+ (int fd, const void *buf, size_t bufsize, off_t offset));
+# else
+# if !...@have_pwrite@
+_GL_FUNCDECL_SYS (pwrite, ssize_t,
+ (int fd, const void *buf, size_t bufsize, off_t offset)
+ _GL_ARG_NONNULL ((2)));
+# endif
+_GL_CXXALIAS_SYS (pwrite, ssize_t,
+ (int fd, const void *buf, size_t bufsize, off_t offset));
+# endif
+_GL_CXXALIASWARN (pwrite);
+#elif defined GNULIB_POSIXCHECK
+# undef pwrite
+# if HAVE_RAW_DECL_PWRITE
+_GL_WARN_ON_USE (pwrite, "pwrite is unportable - "
+ "use gnulib module pwrite for portability");
+# endif
+#endif
+
+
#if @GNULIB_READLINK@
/* Read the contents of the symbolic link FILE and place the first BUFSIZE
bytes of it into BUF. Return the number of bytes placed into BUF if
diff --git a/m4/pwrite.m4 b/m4/pwrite.m4
new file mode 100644
index 0000000..4315fde
--- /dev/null
+++ b/m4/pwrite.m4
@@ -0,0 +1,18 @@
+# pwrite.m4 serial 1
+dnl Copyright (C) 2010 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_FUNC_PWRITE],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ dnl Persuade glibc <unistd.h> to declare pread().
+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+ AC_CHECK_FUNCS_ONCE([pwrite])
+ if test $ac_cv_func_pwrite = no; then
+ HAVE_PWRITE=0
+ AC_LIBOBJ([pwrite])
+ fi
+])
diff --git a/m4/unistd_h.m4 b/m4/unistd_h.m4
index b26d0a9..48d06c7 100644
--- a/m4/unistd_h.m4
+++ b/m4/unistd_h.m4
@@ -38,8 +38,9 @@ AC_DEFUN([gl_UNISTD_H],
]], [chown dup2 dup3 environ euidaccess faccessat fchdir fchownat
fsync ftruncate getcwd getdomainname getdtablesize getgroups
gethostname getlogin getlogin_r getpagesize getusershell setusershell
- endusershell lchown link linkat lseek pipe2 pread readlink readlinkat
- rmdir sleep symlink symlinkat ttyname_r unlink unlinkat usleep])
+ endusershell lchown link linkat lseek pipe2 pread pwrite readlink
+ readlinkat rmdir sleep symlink symlinkat ttyname_r unlink unlinkat
+ usleep])
])
AC_DEFUN([gl_UNISTD_MODULE_INDICATOR],
@@ -79,6 +80,7 @@ AC_DEFUN([gl_UNISTD_H_DEFAULTS],
GNULIB_LSEEK=0; AC_SUBST([GNULIB_LSEEK])
GNULIB_PIPE2=0; AC_SUBST([GNULIB_PIPE2])
GNULIB_PREAD=0; AC_SUBST([GNULIB_PREAD])
+ GNULIB_PWRITE=0; AC_SUBST([GNULIB_PWRITE])
GNULIB_READLINK=0; AC_SUBST([GNULIB_READLINK])
GNULIB_READLINKAT=0; AC_SUBST([GNULIB_READLINKAT])
GNULIB_RMDIR=0; AC_SUBST([GNULIB_RMDIR])
@@ -113,6 +115,7 @@ AC_DEFUN([gl_UNISTD_H_DEFAULTS],
HAVE_LINKAT=1; AC_SUBST([HAVE_LINKAT])
HAVE_PIPE2=1; AC_SUBST([HAVE_PIPE2])
HAVE_PREAD=1; AC_SUBST([HAVE_PREAD])
+ HAVE_PWRITE=1; AC_SUBST([HAVE_PWRITE])
HAVE_READLINK=1; AC_SUBST([HAVE_READLINK])
HAVE_READLINKAT=1; AC_SUBST([HAVE_READLINKAT])
HAVE_SLEEP=1; AC_SUBST([HAVE_SLEEP])
@@ -140,6 +143,7 @@ AC_DEFUN([gl_UNISTD_H_DEFAULTS],
REPLACE_LINKAT=0; AC_SUBST([REPLACE_LINKAT])
REPLACE_LSEEK=0; AC_SUBST([REPLACE_LSEEK])
REPLACE_PREAD=0; AC_SUBST([REPLACE_PREAD])
+ REPLACE_PWRITE=0; AC_SUBST([REPLACE_PWRITE])
REPLACE_READLINK=0; AC_SUBST([REPLACE_READLINK])
REPLACE_RMDIR=0; AC_SUBST([REPLACE_RMDIR])
REPLACE_SLEEP=0; AC_SUBST([REPLACE_SLEEP])
diff --git a/modules/pwrite b/modules/pwrite
new file mode 100644
index 0000000..b1adb4b
--- /dev/null
+++ b/modules/pwrite
@@ -0,0 +1,24 @@
+Description:
+pwrite() function: read without changing file offset
+
+Files:
+lib/pwrite.c
+m4/pwrite.m4
+
+Depends-on:
+lseek
+unistd
+
+configure.ac:
+gl_FUNC_PWRITE
+gl_UNISTD_MODULE_INDICATOR([pwrite])
+
+Makefile.am:
+
+Include:
+<unistd.h>
+
+License:
+LGPLv2+
+
+Maintainer:
diff --git a/modules/pwrite-tests b/modules/pwrite-tests
new file mode 100644
index 0000000..567b220
--- /dev/null
+++ b/modules/pwrite-tests
@@ -0,0 +1,14 @@
+Files:
+tests/test-pwrite.c
+tests/test-pwrite.sh
+tests/init.sh
+tests/signature.h
+tests/macros.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-pwrite.sh
+check_PROGRAMS += test-pwrite
diff --git a/modules/unistd b/modules/unistd
index 9ab6835..b5a9d91 100644
--- a/modules/unistd
+++ b/modules/unistd
@@ -53,6 +53,7 @@ unistd.h: unistd.in.h $(CXXDEFS_H) $(ARG_NONNULL_H)
$(WARN_ON_USE_H)
-e 's|@''GNULIB_LSEEK''@|$(GNULIB_LSEEK)|g' \
-e 's|@''GNULIB_PIPE2''@|$(GNULIB_PIPE2)|g' \
-e 's|@''GNULIB_PREAD''@|$(GNULIB_PREAD)|g' \
+ -e 's|@''GNULIB_PWRITE''@|$(GNULIB_PWRITE)|g' \
-e 's|@''GNULIB_READLINK''@|$(GNULIB_READLINK)|g' \
-e 's|@''GNULIB_READLINKAT''@|$(GNULIB_READLINKAT)|g' \
-e 's|@''GNULIB_RMDIR''@|$(GNULIB_RMDIR)|g' \
@@ -87,6 +88,7 @@ unistd.h: unistd.in.h $(CXXDEFS_H) $(ARG_NONNULL_H)
$(WARN_ON_USE_H)
-e 's|@''HAVE_LINKAT''@|$(HAVE_LINKAT)|g' \
-e 's|@''HAVE_PIPE2''@|$(HAVE_PIPE2)|g' \
-e 's|@''HAVE_PREAD''@|$(HAVE_PREAD)|g' \
+ -e 's|@''HAVE_PWRITE''@|$(HAVE_PWRITE)|g' \
-e 's|@''HAVE_READLINK''@|$(HAVE_READLINK)|g' \
-e 's|@''HAVE_READLINKAT''@|$(HAVE_READLINKAT)|g' \
-e 's|@''HAVE_SLEEP''@|$(HAVE_SLEEP)|g' \
@@ -114,6 +116,7 @@ unistd.h: unistd.in.h $(CXXDEFS_H) $(ARG_NONNULL_H)
$(WARN_ON_USE_H)
-e 's|@''REPLACE_LINKAT''@|$(REPLACE_LINKAT)|g' \
-e 's|@''REPLACE_LSEEK''@|$(REPLACE_LSEEK)|g' \
-e 's|@''REPLACE_PREAD''@|$(REPLACE_PREAD)|g' \
+ -e 's|@''REPLACE_PWRITE''@|$(REPLACE_PWRITE)|g' \
-e 's|@''REPLACE_READLINK''@|$(REPLACE_READLINK)|g' \
-e 's|@''REPLACE_RMDIR''@|$(REPLACE_RMDIR)|g' \
-e 's|@''REPLACE_SLEEP''@|$(REPLACE_SLEEP)|g' \
diff --git a/tests/test-pwrite.c b/tests/test-pwrite.c
new file mode 100644
index 0000000..bc8be0b
--- /dev/null
+++ b/tests/test-pwrite.c
@@ -0,0 +1,80 @@
+/* Test the pwrite function.
+ Copyright (C) 2009, 2010 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 <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (pwrite, ssize_t, (int, const void *, size_t, off_t));
+
+#include <sys/types.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "macros.h"
+
+#define N (sizeof buf - 1)
+
+int
+main (void)
+{
+ char const *file = "out";
+ int fd;
+ char buf[] = "0123456789";
+ off_t pos = 2;
+ size_t i;
+ off_t init_pos;
+
+ ASSERT (file);
+
+ fd = open (file, O_CREAT | O_WRONLY, 0600);
+ ASSERT (0 <= fd);
+ ASSERT (write (fd, buf, N) == N);
+ ASSERT (close (fd) == 0);
+
+ fd = open (file, O_WRONLY, 0600);
+ ASSERT (0 <= fd);
+
+ init_pos = lseek (fd, pos, SEEK_SET);
+ ASSERT (init_pos == pos);
+
+ for (i = 0; i < N; i+=2)
+ {
+ const char byte = 'W';
+ ASSERT (pwrite (fd, &byte, 1, i) == 1);
+ ASSERT (lseek (fd, 0, SEEK_CUR) == init_pos);
+ }
+
+ {
+ /* Invalid offset must evoke failure with EINVAL. */
+ const char byte = 'b';
+ ASSERT (pwrite (fd, &byte, 1, (off_t) -1) == -1);
+ ASSERT (errno == EINVAL);
+ }
+
+ ASSERT (close (fd) == 0);
+
+ {
+ char read_buf[N];
+ fd = open (file, O_RDONLY);
+ ASSERT (0 <= fd);
+ ASSERT (read(fd, buf, N) == N);
+ ASSERT (close (fd) == 0);
+ ASSERT (strcmp("W1W3W5W7W9",buf) == 0);
+ }
+ return 0;
+}
diff --git a/tests/test-pwrite.sh b/tests/test-pwrite.sh
new file mode 100755
index 0000000..aab99ed
--- /dev/null
+++ b/tests/test-pwrite.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+. "${srcdir=.}/init.sh"; path_prepend_ .
+
+fail=0
+: | test-pwrite || fail=1
+
+Exit $fail
diff --git a/tests/test-unistd-c++.cc b/tests/test-unistd-c++.cc
index 425731a..2769d04 100644
--- a/tests/test-unistd-c++.cc
+++ b/tests/test-unistd-c++.cc
@@ -138,6 +138,11 @@ SIGNATURE_CHECK (GNULIB_NAMESPACE::pread, ssize_t,
(int, void *, size_t, off_t));
#endif
+#if GNULIB_TEST_PWRITE
+SIGNATURE_CHECK (GNULIB_NAMESPACE::pwrite, ssize_t,
+ (int, const void *, size_t, off_t));
+#endif
+
#if GNULIB_TEST_READLINK
SIGNATURE_CHECK (GNULIB_NAMESPACE::readlink, ssize_t,
(const char *, char *, size_t));
--
1.6.3.3
