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Subject: Re: [OMPI users] problem with 32-bit mpiJava on openmpi-1.9a1r27361
From: Ralph Castain (rhc_at_[hidden])
Date: 2012-09-25 10:17:01


On Sep 25, 2012, at 6:45 AM, Siegmar Gross <Siegmar.Gross_at_[hidden]> wrote:

> Hi,
>
>>> I tried mpiJava on a 32-bit installation of openmpi-1.9a1r27361.
>>> Why doesn't "mpiexec" start a process on my local machine (it
>>> is not a matter of Java, because I have the same behaviour when
>>> I use "hostname")?
>>>
>>> tyr java 133 mpiexec -np 3 -host tyr,sunpc4,sunpc1 \
>>> java -cp $HOME/mpi_classfiles HelloMainWithBarrier
>>> Process 0 of 3 running on sunpc4.informatik.hs-fulda.de
>>> Process 1 of 3 running on sunpc4.informatik.hs-fulda.de
>>> Process 2 of 3 running on sunpc1
>>> ...
>>>
>>> tyr small_prog 142 mpiexec -np 3 -host tyr,sunpc4,sunpc1 hostname
>>> sunpc1
>>> sunpc4.informatik.hs-fulda.de
>>> sunpc4.informatik.hs-fulda.de
>>>
>>
>> No idea - it works fine for me. Do you have an environmental
>> variable, or something in your default MCA param file, that
>> indicates "no_use_local"?
>
> I have only built and installed Open MPI and I have no param file.
> I don't have a mca environment variable.
>
> tyr hello_1 136 grep local \
> /usr/local/openmpi-1.9_64_cc/etc/openmpi-mca-params.conf
> # $sysconf is a directory on a local disk, it is likely that changes
> # component_path = /usr/local/lib/openmpi:~/my_openmpi_components
>
> tyr hello_1 143 env | grep -i mca
> tyr hello_1 144

No ideas - I can't make it behave that way :-(

>
>
>>> The command breaks if I add a Linux machine.
>>
>> Check to ensure that the path and ld_library_path on your linux box
>> is being correctly set to point to the corresponding Linux OMPI libs.
>> It looks like that isn't the case. Remember, the Java bindings are
>> just that - they are bindings that wrap on top of the regular C
>> code. Thus, the underlying OMPI system remains system-dependent,
>> and you must have the appropriate native libraries installed on
>> each machine.
>
> I implemented a small program, which shows these values and they
> are wrong for MPI, but I have no idea why. The two entries at the
> beginning from PATH and LD_LIBRARY_PATH are not from our normal
> environment, because I add these values at the end of the environment
> variables PATH, LD_LIBRARY_PATH_32, and LD_LIBRARY_PATH_64. Afterwards
> I set LD_LIBRARY_PATH to LD_LIBRARY_PATH_64 on a 64-bit Solaris
> machine, to LD_LIBRARY_PATH_32 followed by LD_LIBRARY_PATH_64 on a
> 64-bit Linux machine, and to LD_LIBRARY_PATH_32 on every 32-bit
> machine.
>

I see the problem - our heterogeneous support could use some improvement, but it'll be awhile before I can get to it.

What's happening is that we are picking up and propagating the prefix you specified, prepending it to your path and ld_library_path. Did you by chance configure with --enable-orterun-prefix-by-default? Or specify --prefix on your cmd line? Otherwise, it shouldn't be doing this. For this purpose, you cannot use either of those options.

Also, you'll need to add --enable-heterogeneous to your configure so the MPI layer builds the right support, and add --hetero-nodes to your cmd line.

>
> Now 1 slave tasks are sending their environment.
>
> Environment from task 1:
> message type: 3
> msg length: 4622 characters
> message:
> hostname: tyr.informatik.hs-fulda.de
> operating system: SunOS
> release: 5.10
> processor: sun4u
> PATH
> /usr/local/openmpi-1.9_64_cc/bin (!!!)
> /usr/local/openmpi-1.9_64_cc/bin (!!!)
> /usr/local/eclipse-3.6.1
> ...
> /usr/local/openmpi-1.9_64_cc/bin (<- from our environment)
> LD_LIBRARY_PATH_32
> /usr/lib
> /usr/local/jdk1.7.0_07/jre/lib/sparc
> ...
> /usr/local/openmpi-1.9_64_cc/lib (<- from our environment)
> LD_LIBRARY_PATH_64
> /usr/lib/sparcv9
> /usr/local/jdk1.7.0_07/jre/lib/sparcv9
> ...
> /usr/local/openmpi-1.9_64_cc/lib64 (<- from our environment)
> LD_LIBRARY_PATH
> /usr/local/openmpi-1.9_64_cc/lib (!!!)
> /usr/local/openmpi-1.9_64_cc/lib64 (!!!)
> /usr/lib/sparcv9
> /usr/local/jdk1.7.0_07/jre/lib/sparcv9
> ...
> /usr/local/openmpi-1.9_64_cc/lib64 (<- from our environment)
> CLASSPATH
> /usr/local/junit4.10
> /usr/local/junit4.10/junit-4.10.jar
> //usr/local/jdk1.7.0_07/j3d/lib/ext/j3dcore.jar
> //usr/local/jdk1.7.0_07/j3d/lib/ext/j3dutils.jar
> //usr/local/jdk1.7.0_07/j3d/lib/ext/vecmath.jar
> /usr/local/javacc-5.0/javacc.jar
> .
>
>
> Without MPI the program uses our environment.
>
> tyr hello_1 147 diff env_with*
> 1,7c1
> <
> <
> < Now 1 slave tasks are sending their environment.
> <
> < Environment from task 1:
> < message type: 3
> < msg length: 4622 characters
> ---
>> Environment:
> 14,15d7
> < /usr/local/openmpi-1.9_64_cc/bin
> < /usr/local/openmpi-1.9_64_cc/bin
> 81,82d72
> < /usr/local/openmpi-1.9_64_cc/lib
> < /usr/local/openmpi-1.9_64_cc/lib64
> tyr hello_1 148
>
>
> I have attached the programs so that you can check yourself and
> hopefully get the same results. Do you modify PATH and LD_LIBRARY_PATH?
>
>
> Kind regards
>
> Siegmar
>
>
>
>
>
>>> tyr java 110 mpiexec -np 3 -host tyr,sunpc4,linpc4 \
>>> java -cp $HOME/mpi_classfiles HelloMainWithBarrier
>>> --------------------------------------------------------------------------
>>> It looks like opal_init failed for some reason; your parallel process is
>>> likely to abort. There are many reasons that a parallel process can
>>> fail during opal_init; some of which are due to configuration or
>>> environment problems. This failure appears to be an internal failure;
>>> here's some additional information (which may only be relevant to an
>>> Open MPI developer):
>>>
>>> mca_base_open failed
>>> --> Returned value -2 instead of OPAL_SUCCESS
>>> --------------------------------------------------------------------------
>>> --------------------------------------------------------------------------
>>> It looks like orte_init failed for some reason; your parallel process is
>>> likely to abort. There are many reasons that a parallel process can
>>> fail during orte_init; some of which are due to configuration or
>>> environment problems. This failure appears to be an internal failure;
>>> here's some additional information (which may only be relevant to an
>>> Open MPI developer):
>>>
>>> opal_init failed
>>> --> Returned value Out of resource (-2) instead of ORTE_SUCCESS
>>> --------------------------------------------------------------------------
>>> --------------------------------------------------------------------------
>>> It looks like MPI_INIT failed for some reason; your parallel process is
>>> likely to abort. There are many reasons that a parallel process can
>>> fail during MPI_INIT; some of which are due to configuration or environment
>>> problems. This failure appears to be an internal failure; here's some
>>> additional information (which may only be relevant to an Open MPI
>>> developer):
>>>
>>> ompi_mpi_init: orte_init failed
>>> --> Returned "Out of resource" (-2) instead of "Success" (0)
>>> --------------------------------------------------------------------------
>>> *** An error occurred in MPI_Init
>>> *** on a NULL communicator
>>> *** MPI_ERRORS_ARE_FATAL (processes in this communicator will now abort,
>>> *** and potentially your MPI job)
>>> [linpc4:27369] Local abort before MPI_INIT completed successfully;
>>> not able to aggregate error messages, and not able to guarantee
>>> that all other processes were killed!
>>> -------------------------------------------------------
>>> Primary job terminated normally, but 1 process returned
>>> a non-zero exit code.. Per user-direction, the job has been aborted.
>>> -------------------------------------------------------
>>> --------------------------------------------------------------------------
>>> mpiexec detected that one or more processes exited with non-zero status,
>>> thus causing
>>> the job to be terminated. The first process to do so was:
>>>
>>> Process name: [[21095,1],2]
>>> Exit code: 1
>>> --------------------------------------------------------------------------
>>>
>>>
>>> tyr java 111 which mpijavac
>>> /usr/local/openmpi-1.9_32_cc/bin/mpijavac
>>> tyr java 112 more /usr/local/openmpi-1.9_32_cc/bin/mpijavac
>>> #!/usr/bin/env perl
>>>
>>> # WARNING: DO NOT EDIT THE mpijava.pl FILE AS IT IS GENERATED!
>>> # MAKE ALL CHANGES IN mpijava.pl.in
>>>
>>> # Copyright (c) 2011 Cisco Systems, Inc. All rights reserved.
>>> # Copyright (c) 2012 Oracle and/or its affiliates. All rights reserved.
>>>
>>> use strict;
>>>
>>> # The main purpose of this wrapper compiler is to check for
>>> # and adjust the Java class path to include the OMPI classes
>>> # in mpi.jar. The user may have specified a class path on
>>> # our cmd line, or it may be in the environment, so we have
>>> # to check for both. We also need to be careful not to
>>> # just override the class path as it probably includes classes
>>> # they need for their application! It also may already include
>>> # the path to mpi.jar, and while it doesn't hurt anything, we
>>> # don't want to include our class path more than once to avoid
>>> # user astonishment
>>>
>>> # Let the build system provide us with some critical values
>>> my $my_compiler = "/usr/local/jdk1.7.0_07/bin/javac";
>>> my $ompi_classpath = "/usr/local/openmpi-1.9_32_cc/lib/mpi.jar";
>>>
>>> # globals
>>> my $showme_arg = 0;
>>> my $verbose = 0;
>>> my $my_arg;
>>> ...
>>>
>>>
>>> All libraries are available.
>>>
>>> tyr java 113 ldd /usr/local/jdk1.7.0_07/bin/javac
>>> libthread.so.1 => /usr/lib/libthread.so.1
>>> libjli.so =>
>>> /export2/prog/SunOS_sparc/jdk1.7.0_07/bin/../jre/lib/sparc/jli/libjli.so
>>> libdl.so.1 => /usr/lib/libdl.so.1
>>> libc.so.1 => /usr/lib/libc.so.1
>>> libm.so.2 => /usr/lib/libm.so.2
>>> /platform/SUNW,A70/lib/libc_psr.so.1
>>> tyr java 114 ssh sunpc4 ldd /usr/local/jdk1.7.0_07/bin/javac
>>> libthread.so.1 => /usr/lib/libthread.so.1
>>> libjli.so =>
>>> /usr/local/jdk1.7.0_07/bin/../jre/lib/i386/jli/libjli.so
>>> libdl.so.1 => /usr/lib/libdl.so.1
>>> libc.so.1 => /usr/lib/libc.so.1
>>> libm.so.2 => /usr/lib/libm.so.2
>>> tyr java 115 ssh linpc4 ldd /usr/local/jdk1.7.0_07/bin/javac
>>> linux-gate.so.1 => (0xffffe000)
>>> libpthread.so.0 => /lib/libpthread.so.0 (0xf77b2000)
>>> libjli.so => /usr/local/jdk1.7.0_07/bin/../jre/lib/i386/jli/libjli.so
>>> (0xf779d000)
>>> libdl.so.2 => /lib/libdl.so.2 (0xf7798000)
>>> libc.so.6 => /lib/libc.so.6 (0xf762b000)
>>> /lib/ld-linux.so.2 (0xf77ce000)
>>>
>>>
>>> I don't have any errors in the log files except the error for nfs.
>>>
>>> tyr openmpi-1.9-Linux.x86_64.32_cc 136 ls log.*
>>> log.configure.Linux.x86_64.32_cc log.make-install.Linux.x86_64.32_cc
>>> log.make-check.Linux.x86_64.32_cc log.make.Linux.x86_64.32_cc
>>>
>>> tyr openmpi-1.9-Linux.x86_64.32_cc 137 grep "Error 1" log.*
>>> log.make-check.Linux.x86_64.32_cc:make[3]: *** [check-TESTS] Error 1
>>> log.make-check.Linux.x86_64.32_cc:make[1]: *** [check-recursive] Error 1
>>> log.make-check.Linux.x86_64.32_cc:make: *** [check-recursive] Error 1
>>>
>>> ...
>>> SUPPORT: OMPI Test failed: opal_path_nfs() (1 of 32 failed)
>>> FAIL: opal_path_nfs
>>> ========================================================
>>> 1 of 2 tests failed
>>> Please report to http://www.open-mpi.org/community/help/
>>> ========================================================
>>> make[3]: *** [check-TESTS] Error 1
>>> ...
>>>
>>>
>>> It doesn't help to build the class files on Linux (which should be
>>> independent of the architecture anyway).
>>>
>>> tyr java 131 ssh linpc4
>>> linpc4 fd1026 98 cd .../prog/mpi/java
>>> linpc4 java 99 make clean
>>> rm -f /home/fd1026/mpi_classfiles/HelloMainWithBarrier.class \
>>> /home/fd1026/mpi_classfiles/HelloMainWithoutBarrier.class
>>> linpc4 java 100 make
>>> mpijavac -d /home/fd1026/mpi_classfiles HelloMainWithBarrier.java
>>> mpijavac -d /home/fd1026/mpi_classfiles HelloMainWithoutBarrier.java
>>>
>>> linpc4 java 101 mpiexec -np 3 -host linpc4 \
>>> java -cp $HOME/mpi_classfiles HelloMainWithBarrier
>>> --------------------------------------------------------------------------
>>> It looks like opal_init failed for some reason; your parallel process is
>>> likely to abort. There are many reasons that a parallel process can
>>> fail during opal_init; some of which are due to configuration or
>>> environment problems. This failure appears to be an internal failure;
>>> here's some additional information (which may only be relevant to an
>>> Open MPI developer):
>>>
>>> mca_base_open failed
>>> --> Returned value -2 instead of OPAL_SUCCESS
>>> ...
>>>
>>> Has anybody else this problem as well? Do you know a solution?
>>> Thank you very much for any help in advance.
>>>
>>>
>>> Kind regards
>>>
>>> Siegmar
>>>
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
> /* A small MPI program, which delivers some information about its
> * machine, operating system, and some environment variables.
> *
> *
> * Compiling:
> * Store executable(s) into local directory.
> * mpicc -o <program name> <source code file name>
> *
> * Store executable(s) into predefined directories.
> * make
> *
> * Make program(s) automatically on all specified hosts. You must
> * edit the file "make_compile" and specify your host names before
> * you execute it.
> * make_compile
> *
> * Running:
> * LAM-MPI:
> * mpiexec -boot -np <number of processes> <program name>
> * or
> * mpiexec -boot \
> * -host <hostname> -np <number of processes> <program name> : \
> * -host <hostname> -np <number of processes> <program name>
> * or
> * mpiexec -boot [-v] -configfile <application file>
> * or
> * lamboot [-v] [<host file>]
> * mpiexec -np <number of processes> <program name>
> * or
> * mpiexec [-v] -configfile <application file>
> * lamhalt
> *
> * OpenMPI:
> * "host1", "host2", and so on can all have the same name,
> * if you want to start a virtual computer with some virtual
> * cpu's on the local host. The name "localhost" is allowed
> * as well.
> *
> * mpiexec -np <number of processes> <program name>
> * or
> * mpiexec --host <host1,host2,...> \
> * -np <number of processes> <program name>
> * or
> * mpiexec -hostfile <hostfile name> \
> * -np <number of processes> <program name>
> * or
> * mpiexec -app <application file>
> *
> * Cleaning:
> * local computer:
> * rm <program name>
> * or
> * make clean_all
> * on all specified computers (you must edit the file "make_clean_all"
> * and specify your host names before you execute it.
> * make_clean_all
> *
> *
> * File: environ_mpi.c Author: S. Gross
> * Date: 25.09.2012
> *
> */
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <unistd.h>
> #include <sys/utsname.h>
> #include "mpi.h"
>
> #define BUF_SIZE 8192 /* message buffer size */
> #define MAX_TASKS 12 /* max. number of tasks */
> #define SENDTAG 1 /* send message command */
> #define EXITTAG 2 /* termination command */
> #define MSGTAG 3 /* normal message token */
>
> #define ENTASKS -1 /* error: too many tasks */
>
> static void master (void);
> static void slave (void);
>
> int main (int argc, char *argv[])
> {
> int mytid, /* my task id */
> ntasks; /* number of parallel tasks */
>
> MPI_Init (&argc, &argv);
> MPI_Comm_rank (MPI_COMM_WORLD, &mytid);
> MPI_Comm_size (MPI_COMM_WORLD, &ntasks);
>
> if (mytid == 0)
> {
> master ();
> }
> else
> {
> slave ();
> }
> MPI_Finalize ();
> return EXIT_SUCCESS;
> }
>
>
> /* Function for the "master task". The master sends a request to all
> * slaves asking for a message. After receiving and printing the
> * messages he sends all slaves a termination command.
> *
> * input parameters: not necessary
> * output parameters: not available
> * return value: nothing
> * side effects: no side effects
> *
> */
> void master (void)
> {
> int ntasks, /* number of parallel tasks */
> mytid, /* my task id */
> num, /* number of entries */
> i; /* loop variable */
> char buf[BUF_SIZE + 1]; /* message buffer (+1 for '\0') */
> MPI_Status stat; /* message details */
>
> MPI_Comm_rank (MPI_COMM_WORLD, &mytid);
> MPI_Comm_size (MPI_COMM_WORLD, &ntasks);
> if (ntasks > MAX_TASKS)
> {
> fprintf (stderr, "Error: Too many tasks. Try again with at most "
> "%d tasks.\n", MAX_TASKS);
> /* terminate all slave tasks */
> for (i = 1; i < ntasks; ++i)
> {
> MPI_Send ((char *) NULL, 0, MPI_CHAR, i, EXITTAG, MPI_COMM_WORLD);
> }
> MPI_Finalize ();
> exit (ENTASKS);
> }
> printf ("\n\nNow %d slave tasks are sending their environment.\n\n",
> ntasks - 1);
> /* request messages from slave tasks */
> for (i = 1; i < ntasks; ++i)
> {
> MPI_Send ((char *) NULL, 0, MPI_CHAR, i, SENDTAG, MPI_COMM_WORLD);
> }
> /* wait for messages and print greetings */
> for (i = 1; i < ntasks; ++i)
> {
> MPI_Recv (buf, BUF_SIZE, MPI_CHAR, MPI_ANY_SOURCE,
> MPI_ANY_TAG, MPI_COMM_WORLD, &stat);
> MPI_Get_count (&stat, MPI_CHAR, &num);
> buf[num] = '\0'; /* add missing end-of-string */
> printf ("Environment from task %d:\n"
> " message type: %d\n"
> " msg length: %d characters\n"
> " message: %s\n\n",
> stat.MPI_SOURCE, stat.MPI_TAG, num, buf);
> }
> /* terminate all slave tasks */
> for (i = 1; i < ntasks; ++i)
> {
> MPI_Send ((char *) NULL, 0, MPI_CHAR, i, EXITTAG, MPI_COMM_WORLD);
> }
> }
>
>
> /* Function for "slave tasks". The slave task sends its hostname,
> * operating system name and release, and processor architecture
> * as a message to the master.
> *
> * input parameters: not necessary
> * output parameters: not available
> * return value: nothing
> * side effects: no side effects
> *
> */
> void slave (void)
> {
> struct utsname sys_info; /* system information */
> int mytid, /* my task id */
> num_env_vars, /* # of environment variables */
> i, /* loop variable */
> more_to_do;
> char buf[BUF_SIZE], /* message buffer */
> *env_vars[] = {"PATH",
> "LD_LIBRARY_PATH_32",
> "LD_LIBRARY_PATH_64",
> "LD_LIBRARY_PATH",
> "CLASSPATH"};
> MPI_Status stat; /* message details */
>
> MPI_Comm_rank (MPI_COMM_WORLD, &mytid);
> num_env_vars = sizeof (env_vars) / sizeof (env_vars[0]);
> more_to_do = 1;
> while (more_to_do == 1)
> {
> /* wait for a message from the master task */
> MPI_Recv (buf, BUF_SIZE, MPI_CHAR, 0, MPI_ANY_TAG,
> MPI_COMM_WORLD, &stat);
> if (stat.MPI_TAG != EXITTAG)
> {
> uname (&sys_info);
> strcpy (buf, "\n hostname: ");
> strncpy (buf + strlen (buf), sys_info.nodename,
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), "\n operating system: ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), sys_info.sysname,
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), "\n release: ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), sys_info.release,
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), "\n processor: ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), sys_info.machine,
> BUF_SIZE - strlen (buf));
> for (i = 0; i < num_env_vars; ++i)
> {
> char *env_val, /* pointer to environment value */
> *delimiter = ":" , /* field delimiter for "strtok" */
> *next_tok; /* next token */
>
> env_val = getenv (env_vars[i]);
> if (env_val != NULL)
> {
> if ((strlen (buf) + strlen (env_vars[i]) + 6) < BUF_SIZE)
> {
> strncpy (buf + strlen (buf), "\n ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), env_vars[i],
> BUF_SIZE - strlen (buf));
> }
> else
> {
> fprintf (stderr, "Buffer too small. Couldn't add \"%s\"."
> "\n\n", env_vars[i]);
> }
> /* Get first token in "env_val". "strtok" skips all
> * characters that are contained in the current delimiter
> * string. If it finds a character which is not contained
> * in the delimiter string, it is the start of the first
> * token. Now it searches for the next character which is
> * part of the delimiter string. If it finds one it will
> * overwrite it by a '\0' to terminate the first token.
> * Otherwise the token extends to the end of the string.
> * Subsequent calls of "strtok" use a NULL pointer as first
> * argument and start searching from the saved position
> * after the last token. "strtok" returns NULL if it
> * couldn't find a token.
> */
> next_tok = strtok (env_val, delimiter);
> while (next_tok != NULL)
> {
> if ((strlen (buf) + strlen (next_tok) + 25) < BUF_SIZE)
> {
> strncpy (buf + strlen (buf), "\n ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), next_tok,
> BUF_SIZE - strlen (buf));
> }
> else
> {
> fprintf (stderr, "Buffer too small. Couldn't add \"%s\" "
> "to %s.\n\n", next_tok, env_vars[i]);
> }
> /* get next token */
> next_tok = strtok (NULL, delimiter);
> }
> }
> }
> MPI_Send (buf, strlen (buf), MPI_CHAR, stat.MPI_SOURCE,
> MSGTAG, MPI_COMM_WORLD);
> }
> else
> {
> more_to_do = 0; /* terminate */
> }
> }
> }
> /* A small program, which delivers some information about its
> * machine, operating system, and some environment variables.
> *
> *
> * Compiling:
> * Store executable(s) into local directory.
> * (g)cc -o environ_without_mpi environ_without_mpi.c
> *
> * Running:
> * environ_without_mpi
> *
> *
> * File: environ_without_mpi.c Author: S. Gross
> * Date: 25.09.2012
> *
> */
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <unistd.h>
> #include <sys/utsname.h>
>
> #define BUF_SIZE 8192 /* message buffer size */
>
> int main (int argc, char *argv[])
> {
> struct utsname sys_info; /* system information */
> int num_env_vars, /* # of environment variables */
> i; /* loop variable */
> char buf[BUF_SIZE], /* message buffer */
> *env_vars[] = {"PATH",
> "LD_LIBRARY_PATH_32",
> "LD_LIBRARY_PATH_64",
> "LD_LIBRARY_PATH",
> "CLASSPATH"};
>
> num_env_vars = sizeof (env_vars) / sizeof (env_vars[0]);
> uname (&sys_info);
> strcpy (buf, "\n hostname: ");
> strncpy (buf + strlen (buf), sys_info.nodename,
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), "\n operating system: ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), sys_info.sysname,
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), "\n release: ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), sys_info.release,
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), "\n processor: ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), sys_info.machine,
> BUF_SIZE - strlen (buf));
> for (i = 0; i < num_env_vars; ++i)
> {
> char *env_val, /* pointer to environment value */
> *delimiter = ":" , /* field delimiter for "strtok" */
> *next_tok; /* next token */
>
> env_val = getenv (env_vars[i]);
> if (env_val != NULL)
> {
> if ((strlen (buf) + strlen (env_vars[i]) + 6) < BUF_SIZE)
> {
> strncpy (buf + strlen (buf), "\n ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), env_vars[i],
> BUF_SIZE - strlen (buf));
> }
> else
> {
> fprintf (stderr, "Buffer too small. Couldn't add \"%s\"."
> "\n\n", env_vars[i]);
> }
> /* Get first token in "env_val". "strtok" skips all
> * characters that are contained in the current delimiter
> * string. If it finds a character which is not contained
> * in the delimiter string, it is the start of the first
> * token. Now it searches for the next character which is
> * part of the delimiter string. If it finds one it will
> * overwrite it by a '\0' to terminate the first token.
> * Otherwise the token extends to the end of the string.
> * Subsequent calls of "strtok" use a NULL pointer as first
> * argument and start searching from the saved position
> * after the last token. "strtok" returns NULL if it
> * couldn't find a token.
> */
> next_tok = strtok (env_val, delimiter);
> while (next_tok != NULL)
> {
> if ((strlen (buf) + strlen (next_tok) + 25) < BUF_SIZE)
> {
> strncpy (buf + strlen (buf), "\n ",
> BUF_SIZE - strlen (buf));
> strncpy (buf + strlen (buf), next_tok,
> BUF_SIZE - strlen (buf));
> }
> else
> {
> fprintf (stderr, "Buffer too small. Couldn't add \"%s\" "
> "to %s.\n\n", next_tok, env_vars[i]);
> }
> /* get next token */
> next_tok = strtok (NULL, delimiter);
> }
> }
> }
> printf ("Environment:\n"
> " message: %s\n\n", buf);
> return EXIT_SUCCESS;
> }