Bug 48454

Summary: "Bad file descriptor"-IOException in CGIServlet for some programs
Product: Tomcat 6 Reporter: Markus Grieder <mgrieder>
Component: CatalinaAssignee: Tomcat Developers Mailing List <dev>
Severity: normal    
Priority: P2    
Version: 6.0.20   
Target Milestone: default   
Hardware: PC   
OS: Linux   
Attachments: Patch

Description Markus Grieder 2009-12-29 02:46:52 UTC
Created attachment 24763 [details]

The internal CGIRunner-thread which reads the errorstream logs a "Bad file descriptor"-IOException everytime i called a program (see stacktrace at the end). The program works fine, but the log-messages disturb.

I could reproduce the behaviour with Nagiostat as CGI-Program (http://nagiostat.sourceforge.net/). I think the behaviour depends on how fast the cgi-program will return, because I haven't the error with another cgi-program on the same machine.

Looking at the code shows that the Process-Object in CGIRunner could be destroyed before the internal Thread has a chance to completely read the errorstream.  

I fixed the problem in CGIServlet with a errorStreamReaderThread.join(...) before proc.destroy() to allow a clean processing of the errorstream.
This is not yet fixed in tomcat trunk / branch tc6.0.x

Linux, Centos5.3 x64, JDK SUN 1.6.0_17, JBoss AS 5.1.0.GA (based on tomcat6.0)

Patch: The attached Patch is against source of JBossWeb2.1.3. Improvement: The timeout of the join should be configurable.

java.io.IOException: Bad file descriptor
        at java.io.FileInputStream.readBytes(Native Method)
        at java.io.FileInputStream.read(FileInputStream.java:199)
        at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
        at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
        at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
        at java.io.InputStreamReader.read(InputStreamReader.java:167)
        at java.io.BufferedReader.fill(BufferedReader.java:136)
        at java.io.BufferedReader.readLine(BufferedReader.java:299)
        at java.io.BufferedReader.readLine(BufferedReader.java:362)
        at org.apache.catalina.servlets.CGIServlet$CGIRunner.sendToLog(CGIServlet.java:1828)
        at org.apache.catalina.servlets.CGIServlet$CGIRunner.access$400(CGIServlet.java:1388)
        at org.apache.catalina.servlets.CGIServlet$CGIRunner$1.run(CGIServlet.java:1663)
Comment 1 Mark Thomas 2009-12-30 02:47:51 UTC
Thanks for the report and the patch.

I have applied the patch + a configuration option for the timeout to trunk (Tomcat 7) and proposed it for 6.0.x.
Comment 2 Mark Thomas 2010-01-06 02:29:50 UTC
This has been fixed in 6.0.x and will be included in 6.0.23 onwards.