Displaying 20 results from an estimated 500 matches similar to: "Funny output from write syscall"
2009 Jul 24
9
getting extra characters with printf(copyin(a, b))
Hi,
I have a situation where a DTrace script is printing out extra characters, despite the copyin() call giving a specific length. Can anyone think of why this might be? It''s fine the first time all of the probes fire, but on a second run of my generating operations, I get junk in there. For example:
set setop length 5, FOUND KEY, STORED
set setop length 5, FOUND KEY, STORED
get
2006 Aug 08
9
Handling userland char ** pointers
I''ve been trying to get access to a userland string that''s behind a
second level pointer using DTrace, but I can''t seem to get it to work.
I started with the example on the Team DTrace Tips and Tricks slides:
trace(copyinstr(*(uintptr_t *)copyin(arg0, curpsinfo->pr_dmodel ==
PR_MODEL_ILP32 ? 4 : 8)));
And when I couldn''t get it to work, I started
2006 May 24
2
Reading external files with dtrace
I''d like to be able to dynamically read external configuration files within a dtrace script. I know dtrace allows inclusion of C header files but only at the preprocessing stage.
What we need to do is dynamically enable/disable probes based on current application settings. I''d rather not have a bunch of independant scripts running and being started and killed whenever the
2007 Jul 30
3
dtrace
hi fnds,
i want to print the filenames on which the stat system
call is acting when a stat system call is invoked. can anyone can help
me this regard.
Thanks
jeevan
2008 May 20
6
Dtrace queries - predicates & func arg tracing
[1] Predicates in one-liners
I would like to list the probe modules in my executable and then
dynamically create a dscript to trace execution of those modules alone
(by excluding the 3rd party and system libraries). I tried the below
script without success. The conditional given in the predicate is not
taking effect. Why is this so ?
$ dtrace -ln ''pid$target:::
2008 Jul 07
2
copyin having secondary effects.
Dtracing gethostbyname I''m trying to read the h_alias array and all the entries it points to however every time I copyin an entry pointed to by the first entry in teh h_alias array the other entries in the array get corrupted.
So I have ended up with this script:
#!/usr/bin/dtrace -CZs
#include <netdb.h>
pid$target::gethostbyname_r:return
{
self->r = (struct hostent
2005 Jul 28
3
speculative tracing on nevada builds ?
Hi,
Has something related to speculative tracing changed between s10 FCS
and the more recent nevada builds ?
I was trying the specopen.d script from the Dtrace guide on a
nevada machine and it failed with :
dtrace: failed to enable ''./spec.d'': DIF program content is invalid
To try and narrow things down a bit I wrote the following short
script. This works fine on s10, but
2006 Jul 31
5
use tracemem to dump content in function read/write
Hi Expert
I want to use dtrace to monitor the content change of one file. I made following scripts,
#!/usr/sbin/dtrace -s
inline int MYPID = $1;
syscall::write:entry
/pid == MYPID/
{
tracemem(arg1, arg2);
printf("\n");
}
It always has an following error
bash-3.00$ sudo dumpFIFO.dtrace 3836
dtrace: failed to compile script ./dumpFIFO.dtrace: line 19: tracemem( ) argument #2
2007 Apr 18
3
dtrace-discuss: cannot get a ''string'' to print...
hi,
I''m using the PID provider to trace a 32-bit app, prtdiag.
I''m trying to print the value of "propname" (arg1) in the
following func:
int
picl_get_propval_by_name(picl_nodehdl_t nodeh, const char *propname,
void *valbuf, size_t nbytes)
...
i''ve tried many versions, but this is a representative one:
53 this string propname;
54
55
2008 Sep 30
12
dtrace missing ''unlinkat''? showing process stack?
everyone,
Just out of curiosity, I did a
dtrace -n ''syscall:::entry { @num[execname, probefunc] = count(); }''
and looked at the entries produced by ''rm''.
I see everything that rm did, *except* the unlinkat - which is unfortunate because I want to trace which processes have deleted which files.
So - does dtrace contain unlinkat as a probe for a system call?
2007 Feb 13
2
How to print kernel global variable.
I am doing some testing on the adjtime syscall, and I want to
dump out the value of the kernel variable "timedelta", and I
am failing at it. Some of my attempts got "Module is no longer
loaded" and some got "Symbol table entry is not a data object"
I found some info that dtrace can print out kernel global
variable, so what am I missing here?
--
blu
"Remember
2005 Sep 08
3
DTrace typewriter
G''Day Folks,
I''ve found another use of dtrace, this makes your console keyboard
sound like a typewriter.
http://www.brendangregg.com/DTrace/typewriter-0.70.tar.gz
I''ve only tested it on an UltraSPARC 5 and a Pentium laptop so far, more
to follow.
Ok, sorry, not actually a practical use of DTrace. :)
Enjoy!
Brendan
[Sydney, Australia]
2006 Sep 21
1
Dtrace script compilation error.
Hi All,
One of the customer is seeing the following error messages.
He is using a S10U1 system with all latest patches.
Dtrace script is attached.
I am not seeing these error messages on S10U2 system.
What could be the problem?
Thanks,
Gangadhar.
------------------------------------------------------------------------
rroberto at njengsunu60-2:~$ dtrace -AFs /lib/svc/share/kcfd.d
dtrace:
2008 Apr 20
1
dtrace script to monitor file access
A user has asked us to find out who is changing one of their files and how it is being changed. I came up
with the script below:
#!/usr/sbin/dtrace -s
#pragma D option quiet
BEGIN
{
printf("\n Timestamp gid uid pid ppid execname function current directory file name\n\n");
}
syscall::open:entry,
2007 Jul 11
5
Error trying to count return points in functions.
Whilst trying out some D to get an insight into what is the most
common reason for a given function to return, I have bumped
into an error I don''t understand.
The first take on what I was trying to do was:
# dtrace -n ''fbt:ip:ip_input:return{@home[arg0] = count();}''
and all was well. The next step was:
# dtrace -n
2008 Aug 19
5
How accurate is "ustack"?
I have been doing some profiling using the profile provider. I have a
command that runs more slowly on the T1000 than it does on prior
systems and I am trying to find out why. Using the profile provider at
1000 hz, and aggregating on the ustack output, I find that the same
function appears at the top of the stack on both platforms, but on
each there are specific instruction locations within
2007 Jul 13
1
how to get scratch buffer in dtrace.
the Subroutines copyinto copies data at user address to scratch buffer, but how can i get the buffer used by the 3rd argument in copyinto;
thanks.
--
This message posted from opensolaris.org
2008 May 21
9
Slow pkginstalls due to long door_calls to nscd
Hi all,
I am installing a zone onto two different V445s running S10U4 and the
zones are taking hours to install (about 1000 packages), that is, the
problem is identical on both systems. A bit of trussing and dtracing has
shown that the pkginstalls being run by the zoneadm install are making
door_call calls to nscd that are taking very long, so far observed to be
5 to 40 seconds, but always in
2006 Jan 12
5
dtrace and follow fork
I am trying to use dtrace to trace all sscanf calls.
I am able to use pid provider for this.
But my application forks off children at times to
handle requests.
Is there a way I can stop the child process
immediately after it is started so that
I can attach a pid provider to that and trace the
scanf calls in it?
I have tried using the "create" probe but that did
not help.
2006 Sep 06
3
Dtrace Snooping
Dear dtrace Experts,
I have seen some dtrace utilities like opensnoop and execsnoop etc.
My interest is to write a simple script that can snoop the files which
uses the 3 syscalls like open,create,unlink.
I have gone through dtrace oneliners that can do the same :
dtrace -n ''syscall::open*:entry { printf("%s %s",execname,copyinstr(arg0));}''
dtrace -n