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authorJim Meyering <jim@meyering.net>2002-12-01 11:36:50 +0000
committerJim Meyering <jim@meyering.net>2002-12-01 11:36:50 +0000
commitef266f5a81f6f1ce28747cd5431bebf0cd720545 (patch)
tree666bb71b092a42bb59165af51151891818d437c3
parent68fd2c3b6873448ae2d554e1380f76a32aa2e980 (diff)
downloadcoreutils-ef266f5a81f6f1ce28747cd5431bebf0cd720545.tar.xz
from gnulib
-rw-r--r--lib/safe-write.c83
-rw-r--r--lib/safe-write.h23
2 files changed, 106 insertions, 0 deletions
diff --git a/lib/safe-write.c b/lib/safe-write.c
new file mode 100644
index 000000000..55962039e
--- /dev/null
+++ b/lib/safe-write.c
@@ -0,0 +1,83 @@
+/* An interface to write() that retries after interrupts.
+ Copyright (C) 1993, 1994, 1998, 2002 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification. */
+#include "safe-write.h"
+
+/* Get ssize_t. */
+#include <sys/types.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#include <errno.h>
+#ifndef errno
+extern int errno;
+#endif
+
+#include <limits.h>
+
+/* We don't pass an nbytes count > SSIZE_MAX to write() - POSIX says the
+ effect would be implementation-defined. Also we don't pass an nbytes
+ count > INT_MAX but <= SSIZE_MAX to write() - this triggers a bug in
+ Tru64 5.1. */
+#define MAX_BYTES_TO_READ INT_MAX
+
+/* Write up to COUNT bytes at BUF to descriptor FD, retrying if interrupted.
+ Return the actual number of bytes written, zero for EOF, or (size_t) -1
+ for an error. */
+size_t
+safe_write (int fd, const void *buf, size_t count)
+{
+ size_t total_written = 0;
+
+ if (count > 0)
+ {
+ const char *ptr = (const char *) buf;
+ do
+ {
+ size_t nbytes_to_write = count;
+ ssize_t result;
+
+ /* Limit the number of bytes to write in one round, to avoid running
+ into unspecified behaviour. But keep the file pointer block
+ aligned when doing so. */
+ if (nbytes_to_write > MAX_BYTES_TO_READ)
+ nbytes_to_write = MAX_BYTES_TO_READ & ~8191;
+
+ result = write (fd, ptr, nbytes_to_write);
+ if (result < 0)
+ {
+#ifdef EINTR
+ if (errno == EINTR)
+ continue;
+#endif
+ return result;
+ }
+ total_written += result;
+ ptr += result;
+ count -= result;
+ }
+ while (count > 0);
+ }
+
+ return total_written;
+}
diff --git a/lib/safe-write.h b/lib/safe-write.h
new file mode 100644
index 000000000..25d1a4d48
--- /dev/null
+++ b/lib/safe-write.h
@@ -0,0 +1,23 @@
+/* An interface to write() that retries after interrupts.
+ Copyright (C) 2002 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#include <stddef.h>
+
+/* Write up to COUNT bytes at BUF to descriptor FD, retrying if interrupted.
+ Return the actual number of bytes written, zero for EOF, or (size_t) -1
+ for an error. */
+extern size_t safe_write (int fd, const void *buf, size_t count);