Hi Fons,
maybe it is related to the signal handling in Root. Could you explain
what should happen on SIGCHLD? The problem seems to disappear when I
comment SIGCHLD record from the gSignalMap in TUnixSystem.cxx.
Jiri
Fons Rademakers <Fons.Rademakers@cern.ch> writes:
> Hi Jiri,
>
> I've seen the same on my linux machine (run stress two times and the second
> will be scrambled. It is related to the OpenPipe() call. If you could debug
> and fix this for me I would be very happy.
>
> Cheers, Fons.
>
>
> masik@fzu.cz wrote:
> >
> > Hi,
> >
> > has anybody seen a problem reading output of external commands by
> > fgets after popen (gSystem->OpenPipe) call? It can be noticed as a
> > garbage/empty line at the end of test/stress output where system info
> > is being obtained. I've seen this on Debian/PPC and some Debian/x86
> > (but not all machines fail). As for non-linux boxes I had a chance to
> > test only dxplus(OSF1) at CERN for which it is less frequent but it
> > happens too. Root version is 3.01/06, libc-2.2.3-6, Linux version
> > 2.4.6-pre8, gcc-3.0.
> >
> > Please see the following example
> >
> > --------------------------------------------------------------------------------
> > Name: poproot2.cxx
> > poproot2.cxx Type: text/x-c++src
> > Description: poproot2.cxx
> >
> > --------------------------------------------------------------------------------
> >
> > [dxplus02] /afs/cern.ch/user/j/jmasik/public > g++ -I$ROOTSYS/include
> > poproot2.cxx `root-config --libs`
> > [dxplus02] /afs/cern.ch/user/j/jmasik/public > ./a.out
> > fgets returned NULL
> > [dxplus02] /afs/cern.ch/user/j/jmasik/public > ./a.out
> > * OSF1 dxplus02 V4.0 1229 alpha
> >
> > Any information on popen and fgets I have doesn't mention the need to
> > test anything beyond returned pointers. Bad runs have this line in
> > their tracelogs.
> > read(4, 0x30018000, 4096) = ? ERESTARTSYS (To be restarted)
> >
> > Do you have an idea what's wrong? Everything works if I comment out
> > TSystem.h and remove `root-config --libs` from the compile command on
> > Debian/PPC, on OSF removing TSystem.h is enough.
> >
> > Jiri
> >
> > I don't know how to strace on OSF, on Linux it looks like
> > ....
> > open("/data/masik/root-v3.02.gcc3/include/RQ_OBJECT.h", O_RDONLY) = 3
> > brk(0x103ae000) = 0x103ae000
> > fstat64(0x3, 0x7fffe938) = 0
> > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> > 0) = 0x30017000
> > read(3, "// @(#)root/base:$Name: $:$Id: "..., 4096) = 4096
> > _llseek(0x3, 0, 0, 0x7fffe8f8, 0) = 0
> > read(3, "// @(#)root/base:$Name: $:$Id: "..., 4096) = 4096
> > read(3, "ar *method) \\\n { Emit(\"Chan"..., 4096) = 152
> > read(3, "", 4096) = 0
> > pipe([4, 5]) = 0
> > fork() = 4880
> > close(5) = 0
> > fstat64(0x4, 0x7ffff0c8) = 0
> > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> > 0) = 0x30018000
> > read(4, 0x30018000, 4096) = ? ERESTARTSYS (To be
> > restarted)
> > --- SIGCHLD (Child exited) ---
> > fstat64(0x1, 0x7fffe9e8) = 0
> > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> > 0) = 0x30019000
> > ioctl(1, 0x402c7413, 0x7fffe848) = 0
> > write(1, "fgets returned NULL\n", 20) = 20
>
> --
> Org: CERN, European Laboratory for Particle Physics.
> Mail: 1211 Geneve 23, Switzerland
> E-Mail: Fons.Rademakers@cern.ch Phone: +41 22 7679248
> WWW: http://root.cern.ch/~rdm/ Fax: +41 22 7677910
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