176 lines
4.9 KiB
Plaintext
176 lines
4.9 KiB
Plaintext
/* dl_vmesa.xs
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*
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* Platform: VM/ESA, possibly others which use dllload etc.
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* Author: Neale Ferguson (neale@mailbox.tabnsw.com.au)
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* Created: 23rd Septemer, 1998
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*
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*
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*/
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/* Porting notes:
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Definition of VM/ESA dynamic Linking functions
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==============================================
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In order to make this implementation easier to understand here is a
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quick definition of the VM/ESA Dynamic Linking functions which are
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used here.
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dlopen
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------
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void *
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dlopen(const char *path)
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This function takes the name of a dynamic object file and returns
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a descriptor which can be used by dlsym later. It returns NULL on
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error.
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dllsym
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------
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void *
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dlsym(void *handle, char *symbol)
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Takes the handle returned from dlopen and the name of a symbol to
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get the address of. If the symbol was found a pointer is
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returned. It returns NULL on error.
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dlerror
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-------
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char * dlerror()
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Returns a null-terminated string which describes the last error
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that occurred with the other dll functions. After each call to
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dlerror the error message will be reset to a null pointer. The
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SaveError function is used to save the error as soo as it happens.
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Return Types
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============
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In this implementation the two functions, dl_load_file &
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dl_find_symbol, return void *. This is because the underlying SunOS
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dynamic linker calls also return void *. This is not necessarily
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the case for all architectures. For example, some implementation
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will want to return a char * for dl_load_file.
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If void * is not appropriate for your architecture, you will have to
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change the void * to whatever you require. If you are not certain of
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how Perl handles C data types, I suggest you start by consulting
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Dean Roerich's Perl 5 API document. Also, have a look in the typemap
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file (in the ext directory) for a fairly comprehensive list of types
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that are already supported. If you are completely stuck, I suggest you
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post a message to perl5-porters, comp.lang.perl.misc or if you are really
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desperate to me.
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Remember when you are making any changes that the return value from
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dl_load_file is used as a parameter in the dl_find_symbol
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function. Also the return value from find_symbol is used as a parameter
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to install_xsub.
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Dealing with Error Messages
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============================
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In order to make the handling of dynamic linking errors as generic as
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possible you should store any error messages associated with your
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implementation with the StoreError function.
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In the case of VM/ESA the function dlerror returns the error message
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associated with the last dynamic link error. As the VM/ESA dynamic
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linker functions return NULL on error every call to a VM/ESA dynamic
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dynamic link routine is coded like this
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RETVAL = dlopen(filename) ;
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if (RETVAL == NULL)
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SaveError(aTHX_ "%s",dlerror()) ;
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Note that SaveError() takes a printf format string. Use a "%s" as
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the first parameter if the error may contain and % characters.
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*/
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#include "EXTERN.h"
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#include "perl.h"
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#include "XSUB.h"
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#include <dll.h>
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#include "dlutils.c" /* SaveError() etc */
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static void
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dl_private_init(pTHX)
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{
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(void)dl_generic_private_init(aTHX);
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}
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MODULE = DynaLoader PACKAGE = DynaLoader
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BOOT:
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(void)dl_private_init(aTHX);
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void *
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dl_load_file(filename, flags=0)
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char * filename
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int flags
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CODE:
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if (flags & 0x01)
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Perl_warn(aTHX_ "Can't make loaded symbols global on this platform while loading %s",filename);
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DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_load_file(%s,%x):\n", filename,flags));
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RETVAL = dlopen(filename) ;
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DLDEBUG(2,PerlIO_printf(Perl_debug_log, " libref=%lx\n", (unsigned long) RETVAL));
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ST(0) = sv_newmortal() ;
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if (RETVAL == NULL)
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SaveError(aTHX_ "%s",dlerror()) ;
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else
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sv_setiv( ST(0), PTR2IV(RETVAL) );
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void *
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dl_find_symbol(libhandle, symbolname)
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void * libhandle
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char * symbolname
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CODE:
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DLDEBUG(2, PerlIO_printf(Perl_debug_log,
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"dl_find_symbol(handle=%lx, symbol=%s)\n",
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(unsigned long) libhandle, symbolname));
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RETVAL = dlsym(libhandle, symbolname);
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DLDEBUG(2, PerlIO_printf(Perl_debug_log,
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" symbolref = %lx\n", (unsigned long) RETVAL));
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ST(0) = sv_newmortal() ;
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if (RETVAL == NULL)
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SaveError(aTHX_ "%s",dlerror()) ;
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else
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sv_setiv( ST(0), PTR2IV(RETVAL) );
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void
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dl_undef_symbols()
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PPCODE:
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# These functions should not need changing on any platform:
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void
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dl_install_xsub(perl_name, symref, filename="$Package")
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char * perl_name
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void * symref
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char * filename
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CODE:
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DLDEBUG(2,PerlIO_printf(Perl_debug_log, "dl_install_xsub(name=%s, symref=%lx)\n",
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perl_name, (unsigned long) symref));
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ST(0) = sv_2mortal(newRV((SV*)newXS(perl_name,
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(void(*)(pTHX_ CV *))symref,
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filename)));
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char *
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dl_error()
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CODE:
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RETVAL = LastError ;
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OUTPUT:
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RETVAL
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# end.
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