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Re: [PATCH] Handle partial read or write.
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Tue, 09 Oct 2012 11:15:59 +0200
- Subject: Re: [PATCH] Handle partial read or write.
Hi Adam,
Thanks for finding this. I made the GNU format style changes suggested
by Roland, but did not change anything else. Does this look OK to you?
Thanks,
Mark
From 02d7f56c7d27a3a6db98c128ad9829ffe2a27413 Mon Sep 17 00:00:00 2001
From: Adam Markey <adam@etinternational.com>
Date: Tue, 9 Oct 2012 11:05:53 +0200
Subject: [PATCH] Handle partial read or write.
Ran into a situation where pread was returning less data than requested for
remote files on a networked filesystem. This patch modifies the IO wrappers
to request the remaining data as long as no real errors occured.
Signed-off-by: Adam Markey <adam@etinternational.com>
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
lib/ChangeLog | 5 +++++
lib/system.h | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 58 insertions(+), 6 deletions(-)
diff --git a/lib/ChangeLog b/lib/ChangeLog
index 46eeeca..525528a 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,8 @@
+2012-10-09 Adam Markey <adam@etinternational.com>
+
+ * system.h: Changed pwrite_retry, write_retry, and pread_retry to
+ handle case where not all data was read/written.
+
2012-10-08 Jan Kratochvil <jan.kratochvil@redhat.com>
* system.h (eu_static_assert): New macro.
diff --git a/lib/system.h b/lib/system.h
index d9adee9..182b7be 100644
--- a/lib/system.h
+++ b/lib/system.h
@@ -34,6 +34,7 @@
#include <stdint.h>
#include <endian.h>
#include <byteswap.h>
+#include <unistd.h>
#if __BYTE_ORDER == __LITTLE_ENDIAN
# define LE32(n) (n)
@@ -64,12 +65,58 @@ extern int crc32_file (int fd, uint32_t *resp);
#define gettext_noop(Str) Str
-#define pwrite_retry(fd, buf, len, off) \
- TEMP_FAILURE_RETRY (pwrite (fd, buf, len, off))
-#define write_retry(fd, buf, n) \
- TEMP_FAILURE_RETRY (write (fd, buf, n))
-#define pread_retry(fd, buf, len, off) \
- TEMP_FAILURE_RETRY (pread (fd, buf, len, off))
+static inline ssize_t __attribute__ ((unused))
+pwrite_retry (int fd, const void *buf, size_t len, off_t off)
+{
+ ssize_t ret;
+ ssize_t recvd = 0;
+
+ do
+ {
+ ret = TEMP_FAILURE_RETRY (pwrite (fd, buf + recvd, len - recvd,
+ off + recvd));
+ if (ret > 0)
+ recvd += ret;
+ }
+ while (ret > 0 && (size_t) recvd < len);
+
+ return ret < 0 ? ret : recvd;
+}
+
+static inline ssize_t __attribute__ ((unused))
+write_retry (int fd, const void *buf, size_t len)
+{
+ ssize_t ret;
+ ssize_t recvd = 0;
+
+ do
+ {
+ ret = TEMP_FAILURE_RETRY (write (fd, buf + recvd, len - recvd));
+ if (ret > 0)
+ recvd += ret;
+ }
+ while (ret > 0 && (size_t)recvd < len);
+
+ return ret < 0 ? ret : recvd;
+}
+
+static inline ssize_t __attribute__ ((unused))
+pread_retry (int fd, void *buf, size_t len, off_t off)
+{
+ ssize_t ret;
+ ssize_t recvd = 0;
+
+ do
+ {
+ ret = TEMP_FAILURE_RETRY (pread (fd, buf + recvd, len - recvd,
+ off + recvd));
+ if (ret > 0)
+ recvd += ret;
+ }
+ while (ret > 0 && (size_t) recvd < len);
+
+ return ret < 0 ? ret : recvd;
+}
/* We need define two variables, argp_program_version_hook and
--
1.7.11.4