From: "Christoph Egger" <Christoph.Egger@amd.com>
Subject: [PATCH][TOOLS] xentrace: Don't append trace on existing
	file
Date: Thu, 29 Nov 2007 11:30:14 +0100
Message-ID: <200711291130.14821.Christoph.Egger@amd.com>
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Hi!

When you run "xentrace -e <mask> trace.output" the first time, all is fine.
When you run it a second time, then the data is appended which makes you
reading old data with xentrace_format and you interprete it as new data.
This usually happens when you automated tracing guests with xentrace and=20
xentrace_format with a script.

Therefore, attached patch makes xentrace to truncate the file to zero bytes
before writing any data.

Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>


=2D-=20
AMD Saxony, Dresden, Germany
Operating System Research Center

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diff -r e10eacec8b91 tools/xentrace/xentrace.c
--- a/tools/xentrace/xentrace.c	Wed Nov 28 22:36:33 2007 +0000
+++ b/tools/xentrace/xentrace.c	Thu Nov 29 13:28:10 2007 +0100
@@ -581,7 +581,9 @@ int main(int argc, char **argv)
     }
 
     if ( opts.outfile )
-        outfd = open(opts.outfile, O_WRONLY | O_CREAT | O_LARGEFILE, 0644);
+        outfd = open(opts.outfile,
+			O_WRONLY | O_CREAT | O_TRUNC | O_LARGEFILE,
+			0644);
 
     if(outfd < 0)
     {

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