Re: AW: AW: dd killed with USR1 right after ftruncate()

[Pádraig Brady]

Voelker, Bernhard wrote:
> Pádraig wrote:
>> Yep I think so. Moving just the install_signal_handlers() to the top,
> 
> can we expect this to happen in one of the next releases?
> 
>> p.s. I'm still unsure as to why open(O_TRUNC) takes "a while".
>> Perhaps there is a trunc=paranoid mount option I'm unaware of
>> that actually writes zeros when truncating a file.
> 
> I guess this depends on the filesystem type. E.g. on another Solaris10
> box with UFS `dd if=/dev/zero of=$HOME/x bs=1G count=10` takes
> a rather good ~1.5min while the subsequent open(O_TRUNC) then
> takes ~6sec. I don't think zeroes are written there ;-)

Thanks for the clarification.
I guess the file systems need time to deallocate all the blocks.
Right so the attached seems to address the issue and
passes all tests. I don't see much problem with adding
this to the release we're trying to complete this week.

cheers,
Pádraig.

>From 2e4fbc9f1da8d2041f9ea0abd65c5213954f4255 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?P=C3=A1draig=20Brady?= <address@hidden>
Date: Thu, 13 Aug 2009 14:37:43 +0100
Subject: [PATCH] dd: fix a signal handling race

* src/dd.c (main): Install the signal handlers at startup
rather than just before the copy starts. In this way signals
received before the copy (like during a slow truncate for e.g.)
will be deferred and handled consistently.
* THANKS: Add Bernhard's email address.
* NEWS: Mention the fix.
Reported by Bernhard Voelker.
---
 NEWS     |    3 +++
 THANKS   |    1 +
 src/dd.c |    4 ++--
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 6df0d65..a88546d 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,9 @@ GNU coreutils NEWS                                    -*- 
outline -*-
   dd's oflag=direct option now works even when the size of the input
   is not a multiple of e.g., 512 bytes.
 
+  dd now handles signals consistently even when they're received
+  before data copying has started.
+
   install runs faster again with SELinux enabled
   [introduced in coreutils-7.0]
 
diff --git a/THANKS b/THANKS
index d3541ce..bd078db 100644
--- a/THANKS
+++ b/THANKS
@@ -75,6 +75,7 @@ Bernd Melchers                      address@hidden
 Bernhard Baehr                      address@hidden
 Bernhard Gabler                     address@hidden
 Bernhard Rosenkraenzer              address@hidden
+Bernhard Voelker                    address@hidden
 Bert Deknuydt                       address@hidden
 Bert Wesarg                         address@hidden
 Bill Peters                         address@hidden
diff --git a/src/dd.c b/src/dd.c
index d9e4c85..30bd808 100644
--- a/src/dd.c
+++ b/src/dd.c
@@ -1828,6 +1828,8 @@ main (int argc, char **argv)
   int exit_status;
   off_t offset;
 
+  install_signal_handlers ();
+
   initialize_main (&argc, &argv);
   set_program_name (argv[0]);
   setlocale (LC_ALL, "");
@@ -1928,8 +1930,6 @@ main (int argc, char **argv)
        }
     }
 
-  install_signal_handlers ();
-
   start_time = gethrxtime ();
 
   exit_status = dd_copy ();
-- 
1.6.2.5