in reply to Running remote commands (Net::SSH2)

Is Net:SSH2 the way to go?

You'll probably get different recommendations from different people... but personally I've so far had good results with Net::SSH2 in cases where I couldn't use the system ssh. In other words, I wouldn't give up right away with your attempts to install it.

As to the "libssh2.so: undefined reference to dlerror" error, undefined reference problems are often caused by mismatching versions of libraries.  It would help us (to help you) if you posted an exact description of what you did, the verbatim error message in the context where it appeared, the versions of libs/module, the OS you're using, etc.

Replies are listed 'Best First'.
Re^2: Running remote commands (Net::SSH2)
by wilko (Acolyte) on Dec 22, 2009 at 13:55 UTC
    Hi and thanks for your response. Here's what I've got

    > uname -a
    Linux 2.4.21-37.ELsmp #1 SMP Wed Sep 7 13:28:55 EDT 2005 i686 i686 i386 GNU/Linux

    1. Downloaded Net-SSH2-0.28 from CPAN (has dependencies on openssl and libssh
    2. Downloaded and installed openssl-0.9.8l from http://www.openssl.org. All worked OK
    3. Downloaded libssh2-1.2.2 from http://www.libssh2.org/
    4. Untarred and then:

    ./configure --with-libssl-prefix=/usr/local/ssl (seemed to go through fine)
    make

    This is where it goes wrong. It runs through and exits with this:

    /bin/sh ../../libtool --tag=CC --mode=link gcc -g -O2 -o ssh2 ssh2.o ../../src/libssh2.la
    libtool: link: gcc -g -O2 -o .libs/ssh2 ssh2.o ../../src/.libs/libssh2.so -L/usr/local/ssl/lib -lssl -lcrypto -lz -Wl,-rpath -Wl,/usr/local/lib
    ../../src/.libs/libssh2.so: undefined reference to `dlerror'
    ../../src/.libs/libssh2.so: undefined reference to `dlclose'
    ../../src/.libs/libssh2.so: undefined reference to `dlopen'
    ../../src/.libs/libssh2.so: undefined reference to `dlsym'
    collect2: ld returned 1 exit status
    make2: *** ssh2 Error 1
    make2: Leaving directory `/tmp/libssh2-1.2.2/example/simple'
    make1: *** all-recursive Error 1
    make1: Leaving directory `/tmp/libssh2-1.2.2/example'
    make: *** all-recursive Error 1
    Any guidance greatly appreciated. John
[reply]
      /bin/sh ../../libtool --tag=CC --mode=link gcc  -g -O2   -o ssh2  ssh2
+.o ../../src/libssh2.la
libtool: link: gcc -g -O2 -o .libs/ssh2 ssh2.o  ../../src/.libs/libssh
+2.so -L/usr/local/ssl/lib -lssl -lcrypto -lz -Wl,-rpath -Wl,/usr/loca
+l/lib
../../src/.libs/libssh2.so: undefined reference to `dlerror'
../../src/.libs/libssh2.so: undefined reference to `dlclose'
../../src/.libs/libssh2.so: undefined reference to `dlopen'
../../src/.libs/libssh2.so: undefined reference to `dlsym'

      [download]

      Looks like a problem with libdl not having been found during ./configure, so that the required -ldl is missing from the link command  (the dl library implements dlopen etc. which are used for run-time dynamic linking of shared libs).

      Maybe check

      • if you actually have the lib (would typically be in /lib or /lib64 or /usr/lib or /usr/lib64, e.g. /lib/libdl.so.2)
      • what the configure output has to say (--> "checking for dlopen ...", or some such)
      • if the link command succeeds if you manually issue it with -ldl added (from the directory where ssh2.o is), i.e. 
        $ gcc -g -O2 -o .libs/ssh2 ssh2.o  ../../src/.libs/libssh2.so -L/usr/l
+ocal/ssl/lib -ldl -lssl -lcrypto -lz -Wl,-rpath -Wl,/usr/local/lib

        [download]
[reply]
[d/l]
[select]
      From the output it looks like it's missing the -ldl flag, pulling in the dynamic linker lib. Could try that command with -ldl and see what you get. Looks like it should work after that to me.
[reply]
        you mean on the ./configure part? tried that but it complained with

        error: unrecognized option: `-ldl'
[reply]

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