Re: R3.14 and registerRecordDeviceDriver

[Dirk Zimoch <dirk.zimoch@psi.ch>]

Hi Kate and all others,

Kate Feng wrote:
> ... My wish also gives RTEMS or Linux users an option to dynamically
> load a new application code (e.g. ld("new.obj")), which might need a
> new record/device/driver support entry table registered (e.g.
> new_SRCS += new_registerRecordDeviceDriver.cpp) at run time or even
> during an IOC test/development stage, which could occur very often
> during a development cycle. I actually found it handy in beamline
> applications.
> ...

Attached you will find a Linux (UNIX?) implementation of the 'ld'
command. Just link it to your iocsh. On Linux, it can load shared 
libraries (*.so). Maybe the code has to be modified to run on other 
platforms. I used the 'dlopen' function to implement it.

ld ("foo")

Searches LD_LIBRARY_PATH for libfoo.so, foo.so, foo (in this order).
After loading the code, all C++ constructors of global objects are 
executed (for registering, etc.)

I have not tried it on any other platform.

Dirk

--
Dr. Dirk Zimoch
Swiss Light Source
Paul Scherrer Institut
Computing and Controls
phone +41 56 310 5182
fax   +41 56 310 4413

/*
* ld - load code dynamically
*
* $Author$
* $ID$
* $Date$
*
* DISCLAIMER: Use at your own risc and so on. No warranty, no refund.
*/

#include <iocsh.h>
#include <stdio.h>
#include <dlfcn.h>

/* ld (dynamicLibrary) */
static const iocshArg ldArg0 = { "library", iocshArgString };
static const iocshArg * const ldArgs[1] = { &ldArg0 };
static const iocshFuncDef ldFuncDef = { "ld", 1, ldArgs };

static void ldCallFunc (const iocshArgBuf *args)
{
#ifdef UNIX
    char libname[256];
    
    if (!args[0].sval)
    {
        fprintf (stderr, "missing library name");
        return;
    }
    sprintf (libname, "lib%.249s.so", args[0].sval);
    if (dlopen (libname, RTLD_NOW|RTLD_GLOBAL)) return;
    sprintf (libname, "%.252s.so", args[0].sval);
    if (dlopen (libname, RTLD_NOW|RTLD_GLOBAL)) return;
    sprintf (libname, "%.255s", args[0].sval);
    if (dlopen (libname, RTLD_NOW|RTLD_GLOBAL)) return;
    fprintf (stderr, "%s\n", dlerror());
#else
    fprintf (stderr, "not supported for this operating system");
#endif
}

class IocshRegister {
public:
    IocshRegister (const iocshFuncDef& piocshFuncDef, iocshCallFunc func) {
        iocshRegister (&piocshFuncDef, func); }
};

static IocshRegister register_ld (ldFuncDef, ldCallFunc);