RFR [XS] : 8175000 : jexec fails to execute simple helloworld.jar
Kumar Srinivasan
kumar.x.srinivasan at oracle.com
Wed Mar 1 17:51:00 UTC 2017
Hi Baesken,
Thanks for fixing this, BUT......
Has this been tested on other platforms, especially on both the
Endian platforms.
I think we should have a simplistic regression test for this in
jdk/test/tools/launcher area, until we EOL this.
Once we have that then we need to test this on all platforms.
So I will write a test, and test this change, through our test and
build system, please hold off until then.
Thanks
Kumar
> Hi Matthias,
>
> On Wed, Mar 1, 2017 at 5:07 PM, Baesken, Matthias
> <matthias.baesken at sap.com <mailto:matthias.baesken at sap.com>> wrote:
>
> Hi Thomas , thanks for looking into it .
>
> I suggest to handle the read issue in another bug because this
> one just deals with “jexec fails to execute simple helloworld.jar” .
>
> ( there seem to be a few other read(…) calls in the jdk code
> base to consider as well )
>
> Can we push the existing change ?
>
>
> Not a Reviewer, so it is not for me to decide. Someone from core libs
> should look at this.
>
> ...Thomas
>
> Regards, Matthias
>
> *From:*Thomas Stüfe [mailto:thomas.stuefe at gmail.com
> <mailto:thomas.stuefe at gmail.com>]
> *Sent:* Mittwoch, 1. März 2017 12:47
> *To:* Baesken, Matthias <matthias.baesken at sap.com
> <mailto:matthias.baesken at sap.com>>
> *Cc:* core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net>; Simonis, Volker
> <volker.simonis at sap.com <mailto:volker.simonis at sap.com>>
> *Subject:* Re: RFR [XS] : 8175000 : jexec fails to execute simple
> helloworld.jar
>
> Hi Matthias,
>
> the fix makes sense, this is very clearly a bug.
>
> I'd suggest a simpler fix though:
>
> end -= 4; // make sure there are 4 bytes to
> read at start
> - while (start < end) {
> + while (start <= end) {
>
> Note that the code has a diffent bug too, very unlikely but not
> impossible to hit:
>
> 321 ssize_t count = read(fd, buf, CHUNK_SIZE);
> 322 if (count >= MIN_SIZE) {
>
> We attempt to read CHUNK_SIZE bytes and require the read to have
> returned at least MIN_SIZE (something like 30ish bytes). If not,
> jexec fails.
>
> read may have been interrupted (EINTR) or may have returned less
> bytes than MIN_SIZE, so it should read in a loop til eof or
> CHUNK_SIZE bytes are read.
>
> Kind Regards, Thomas
>
> On Wed, Mar 1, 2017 at 10:23 AM, Baesken, Matthias
> <matthias.baesken at sap.com <mailto:matthias.baesken at sap.com>> wrote:
>
> Ping ...
>
> Can I get a review please for the change ?
>
>
> Thanks, Matthias
>
> From: Baesken, Matthias
> Sent: Donnerstag, 23. Februar 2017 12:28
> To: 'core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net>'
> <core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net>>
> Cc: Langer, Christoph <christoph.langer at sap.com
> <mailto:christoph.langer at sap.com>>; Erik Joelsson
> (erik.joelsson at oracle.com <mailto:erik.joelsson at oracle.com>)
> <erik.joelsson at oracle.com <mailto:erik.joelsson at oracle.com>>;
> 'Michel Trudeau' <michel.trudeau at oracle.com
> <mailto:michel.trudeau at oracle.com>>
> Subject: RE: RFR [XS] : 8175000 : jexec fails to execute
> simple helloworld.jar
>
> Here is the webrev for jdk9 :
>
> http://cr.openjdk.java.net/~mbaesken/webrevs/8175000/
> <http://cr.openjdk.java.net/%7Embaesken/webrevs/8175000/>
>
>
> ? And btw I really wonder - is jexec still needed in future
> jdk's like jdk10 ? Seems it is not used much .
>
> ?
>
> In case jexec will stay in the jdk I might add a test for
> the tool as well, if there is interest ( could not really
> find one that tests execution of a simple jar-file with jexec).
>
> Best regards, Matthias
>
>
> From: Baesken, Matthias
> Sent: Donnerstag, 23. Februar 2017 07:39
> To: 'core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net>'
> <core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net><mailto:core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net>>>
>
> Cc: Langer, Christoph <christoph.langer at sap.com
> <mailto:christoph.langer at sap.com><mailto:christoph.langer at sap.com
> <mailto:christoph.langer at sap.com>>>; Erik Joelsson
> (erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com><mailto:erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com>>) <erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com><mailto:erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com>>>
> Subject: RE: RFR [XS] : 8175000 : jexec fails to execute
> simple helloworld.jar
>
> Hello, probably I should add the info that the fix is needed
> in jdk9 as well , not only jdk10 .
>
> Without the fix jdk9/10 show this error when executing a
> small example jar :
>
> /myjdk9/images/jdk/lib/jexec /java_test/hellojar/helloworld.jar
> invalid file (bad magic number): Exec format error
>
> with the fix :
>
> jdk/lib/jexec /java_test/hellojar/helloworld.jar
> Hello world from a jar file
>
>
> And btw I really wonder - is jexec still needed in future
> jdk's like jdk10 ? Seems it is not used much .
>
> Best regards, Matthias
>
>
> From: Baesken, Matthias
> Sent: Mittwoch, 22. Februar 2017 18:16
> To: core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net><mailto:core-libs-dev at openjdk.java.net
> <mailto:core-libs-dev at openjdk.java.net>>
> Cc: Langer, Christoph <christoph.langer at sap.com
> <mailto:christoph.langer at sap.com><mailto:christoph.langer at sap.com
> <mailto:christoph.langer at sap.com>>>; Erik Joelsson
> (erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com><mailto:erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com>>) <erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com><mailto:erik.joelsson at oracle.com
> <mailto:erik.joelsson at oracle.com>>>
> Subject: RFR [XS] : 8175000 : jexec fails to execute simple
> helloworld.jar
>
> Hello , when looking into the jexec build I noticed that
> execution of a simple helloworld.jar with jexec does not
> work any more.
>
> I did a little patch for this which adjusted the addition done
> with CR 8156478: 3 Buffer overrun defect groups in
> jexec.c<https://javapartner.oracle.com/mproxy/repository/technology/java2/jdk9/jdk/rev/4f96129b45ee
> <https://javapartner.oracle.com/mproxy/repository/technology/java2/jdk9/jdk/rev/4f96129b45ee>>
> .
>
> Could I have a review ( just a diff this time is provided
> because of infrastructure issues) for it ?
>
>
> Thanks, Matthias
>
> Bug :
> https://bugs.openjdk.java.net/browse/JDK-8175000
> <https://bugs.openjdk.java.net/browse/JDK-8175000>
>
>
> Diff for jdk10 :
>
> # HG changeset patch
> # User mbaesken
> # Date 1487782485 -3600
> # Wed Feb 22 17:54:45 2017 +0100
> # Node ID 93d55a711f3b1c3f282e6889c24d13f16d4a4548
> # Parent 884872263accabd4ab68d005abd4e5393144aa4f
> 8175000: jexec fails to execute simple helloworld.jar
>
> diff --git a/src/java.base/unix/native/launcher/jexec.c
> b/src/java.base/unix/native/launcher/jexec.c
> --- a/src/java.base/unix/native/launcher/jexec.c
> +++ b/src/java.base/unix/native/launcher/jexec.c
> @@ -331,8 +331,9 @@
> off_t end = start + xlen;
>
> if (end <= count) {
> - end -= 4; // make sure there are 4 bytes
> to read at start
> - while (start < end) {
> + // make sure there are 4 bytes to read at
> start
> + end -= 3;
> + while ((start < end) && (start < count-3)) {
> off_t xhid = SH(buf, start);
> off_t xdlen = SH(buf, start + 2);
>
>
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