jdtrace Example

jdtrace Example

jdtrace is a Java program that emulates dtrace(1M) using the Java DTrace API.  It currently supports the following options:

    Usage: java JDTrace [-32|-64] [-CeFlqvVwZ] [-b bufsz] [-c cmd] [-D name[=def]]
        [-I path] [-L path] [-o output] [-p pid] [-s script] [-U name]
        [-x opt[=val]] [-X a|c|s|t]
    
        [-P provider [[ predicate ] action ]]
        [-m [ provider: ] module [[ predicate ] action ]]
        [-f [[ provider: ] module: ] func [[ predicate ] action ]]
        [-n [[[ provider: ] module: ] func: ] name [[ predicate ] action ]]
        [-i probe-id [[ predicate ] action ]] [ args ... ]  
        predicate -> '/' D-expression '/'
           action -> '{' D-statements '}'
    
        -32 generate 32-bit D programs
        -64 generate 64-bit D programs
    
        -b  set trace buffer size
        -c  run specified command and exit upon its completion
        -C  run cpp(1) preprocessor on script files
        -D  define symbol when invoking preprocessor
        -e  exit after compiling request but prior to enabling probes
        -f  enable or list probes matching the specified function name
        -F  coalesce trace output by function
        -i  enable or list probes matching the specified probe id
        -I  add include directory to preprocessor search path
        -l  list probes matching specified criteria
        -L  add library directory to library search path
        -m  enable or list probes matching the specified module name
        -n  enable or list probes matching the specified probe name
        -o  set output file
        -p  grab specified process-ID and cache its symbol tables
        -P  enable or list probes matching the specified provider name
        -q  set quiet mode (only output explicitly traced data)
        -s  enable or list probes according to the specified D script
        -U  undefine symbol when invoking preprocessor
        -v  set verbose mode (report stability attributes, arguments)
        -V  report DTrace API version
        -w  permit destructive actions
        -x  enable or modify compiler and tracing options
        -X  specify ISO C conformance settings for preprocessor
        -Z  permit probe descriptions that match zero probes
    
        To run remotely use the "host" option with -x:
                -xhost=<hostname> [ -xport=<port-number> ]
    
        To log PrintaRecord, set this environment variable:
                JDTRACE_LOGGING_LEVEL=FINE
        To log ProbeData, set JDTRACE_LOGGING_LEVEL=FINER

Other than the initial 'j', you run it just like dtrace(1M), for example:

    % jdtrace -n 'syscall:::entry { @[execname] = count(); }' -n 'tick-1sec { printa(@); clear(@); }'

Requirements

jdtrace requires the Java DTrace API. Specifically, it requires

/usr/share/lib/java/dtrace.jar (Solaris Nevada build 50 or later)  

Source

Here is the jdtrace source (licensed under CDDL):

jdtrace.tar

Extracting the tar creates a jdtrace directory with the following files:

jdtrace/
jdtrace/Makefile
jdtrace/jdtrace.c
jdtrace/JDTrace.java
jdtrace/Getopt.java
jdtrace/opensolaris.license.txt
jdtrace/jdtrace.jar-manifest

Building jdtrace

Simply run  

    % make

in the extracted directory. The Makefile also supports the clean and clobber targets.

Notes

jdtrace makes it possible to test the Java DTrace API using the existing DTrace test suite. I hope it also provides useful examples of how to access common DTrace functionality using the API.