/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "NPL"); you may not use this file except in
 * compliance with the NPL.  You may obtain a copy of the NPL at
 * http://www.mozilla.org/NPL/
 * 
 * Software distributed under the NPL is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
 * for the specific language governing rights and limitations under the
 * NPL.
 * 
 * The Initial Developer of this code under the NPL is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 */

#include "primpl.h"

#include <string.h>

#ifdef XP_MAC
#include <CodeFragments.h>
#include <TextUtils.h>
#include <Types.h>
#include <Strings.h>
#endif

#ifdef XP_UNIX
#ifdef USE_DLFCN
#include <dlfcn.h>
#elif defined(USE_HPSHL)
#include <dl.h>
#elif defined(USE_RLD)
#include <mach-o/dyld.h>
#endif

/* Define this on systems which don't have it (AIX) */
#ifndef RTLD_LAZY
#define RTLD_LAZY RTLD_NOW
#endif
#endif /* XP_UNIX */

#ifdef XP_PC
typedef PRStaticLinkTable *NODL_PROC(void);
#endif

/************************************************************************/

struct PRLibrary {
    char*			name;  /* Our own copy of the name string */
    PRLibrary*			next;
    int				refCount;
    const PRStaticLinkTable*	staticTable;

#ifdef XP_PC
    HINSTANCE			dlh;
#endif
#ifdef XP_MAC
    CFragConnectionID		dlh;
#endif

#ifdef XP_UNIX
#if defined(USE_HPSHL)
    shl_t			dlh;
#elif defined(USE_RLD)
    NSModule			dlh;
#else
    void*			dlh;
#endif 
#endif 
};

static PRLibrary *pr_loadmap;
static PRLibrary *pr_exe_loadmap;
static PRMonitor *pr_linker_lock;
static char* _pr_currentLibPath = NULL;

/************************************************************************/

#if !defined(USE_DLFCN) && !defined(HAVE_STRERROR)
static char* errStrBuf = NULL;
#define ERR_STR_BUF_LENGTH	20
static char* errno_string(PRIntn oserr)
{
    if (errStrBuf == NULL)
	    errStrBuf = PR_MALLOC(ERR_STR_BUF_LENGTH);
    PR_snprintf(errStrBuf, ERR_STR_BUF_LENGTH, "error %d", oserr);
    return errStrBuf;
}
#endif

static void DLLErrorInternal(PRIntn oserr)
/*
** This whole function, and most of the code in this file, are run
** with a big hairy lock wrapped around it. Not the best of situations,
** but will eventually come up with the right answer.
*/
{
    const char *error = NULL;
#ifdef USE_DLFCN
    error = dlerror();  /* $$$ That'll be wrong some of the time - AOF */
#elif defined(HAVE_STRERROR)
    error = strerror(oserr);  /* this should be okay */
#elif defined(XP_PC)
    error = errno_string(GetLastError());
#else
    error = errno_string(oserr);
#endif
    if (NULL != error)
        PR_SetErrorText(strlen(error), error);
}  /* DLLErrorInternal */

void _PR_InitLinker(void)
{
#ifndef XP_MAC
    PRLibrary *lm;
#endif
#if defined(XP_UNIX)
    void *h;
#endif

    if (!pr_linker_lock) {
        pr_linker_lock = PR_NewNamedMonitor("linker-lock");
    }
    PR_EnterMonitor(pr_linker_lock);

#if defined(XP_PC)
    lm = PR_NEWZAP(PRLibrary);
    lm->name = strdup("Executable");
        /* 
        ** In WIN32, GetProcAddress(...) expects a module handle in order to
        ** get exported symbols from the executable...
        **
        ** However, in WIN16 this is accomplished by passing NULL to 
        ** GetProcAddress(...)
        */
#if defined(_WIN32)
        lm->dlh = GetModuleHandle(NULL);
#else
        lm->dlh = (HINSTANCE)NULL;
#endif /* ! _WIN32 */

	lm->refCount    = 1;
    lm->staticTable = NULL;
	pr_exe_loadmap  = lm;
	pr_loadmap      = lm;

#elif defined(XP_UNIX)
#ifdef HAVE_DLL
#ifdef USE_DLFCN
    h = dlopen(0, RTLD_LAZY);
	if (!h) {
		char *error;
		
		DLLErrorInternal(_MD_ERRNO());
		error = (char*)PR_MALLOC(PR_GetErrorTextLength());
		(void) PR_GetErrorText(error);
	    fprintf(stderr, "failed to initialize shared libraries [%s]\n",
		    error);
		PR_DELETE(error);
	    abort();/* XXX */
	}
#elif defined(USE_HPSHL)
	h = NULL;
	/* don't abort with this NULL */
#elif defined(USE_RLD)
	h = NULL; /* XXXX  toshok */
#else
#error no dll strategy
#endif /* USE_DLFCN */

    lm = PR_NEWZAP(PRLibrary);
    if (lm) {
        lm->name = strdup("a.out");
    	lm->refCount = 1;
        lm->dlh = h;
        lm->staticTable = NULL;
    }
    pr_exe_loadmap = lm;
    pr_loadmap = lm;
#endif /* HAVE_DLL */
#endif /* XP_UNIX */

#ifndef XP_MAC
    PR_LOG(_pr_linker_lm, PR_LOG_MIN, ("Loaded library %s (init)", lm?lm->name:"NULL"));
#endif

    PR_ExitMonitor(pr_linker_lock);
}

#if defined(WIN16)
void _PR_ShutdownLinker(void)
{
    PR_EnterMonitor(pr_linker_lock);

    while (pr_loadmap) {
	if (pr_loadmap->refCount > 1) {
#ifdef DEBUG
	    fprintf(stderr, "# Forcing library to unload: %s (%d outstanding references)\n",
		    pr_loadmap->name, pr_loadmap->refCount);
#endif
	    pr_loadmap->refCount = 1;
	}
	PR_UnloadLibrary(pr_loadmap);
    }
    
    PR_ExitMonitor(pr_linker_lock);

    PR_DestroyMonitor(pr_linker_lock);
    pr_linker_lock = NULL;
}
#endif

/******************************************************************************/

PR_IMPLEMENT(PRStatus) PR_SetLibraryPath(const char *path)
{
    PRStatus rv = PR_SUCCESS;

    PR_EnterMonitor(pr_linker_lock);
    PR_FREEIF(_pr_currentLibPath);
    if (path) {
        _pr_currentLibPath = strdup(path);
        if (!_pr_currentLibPath) {
            PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
	    rv = PR_FAILURE;
        }
    } else {
        _pr_currentLibPath = 0;
    }
    PR_ExitMonitor(pr_linker_lock);
    return rv;
}

/*
** Return the library path for finding shared libraries.
*/
PR_IMPLEMENT(char *) 
PR_GetLibraryPath()
{
    char *ev;
    char *copy = NULL;  /* a copy of _pr_currentLibPath */

    PR_EnterMonitor(pr_linker_lock);
    if (_pr_currentLibPath != NULL) {
        goto exit;
    }

    /* initialize pr_currentLibPath */

#ifdef XP_PC
    ev = getenv("LD_LIBRARY_PATH");
    if (!ev) {
	ev = ".;\\lib";
    }
    ev = strdup(ev);
#endif

#ifdef XP_MAC
	{
	char *p;
	int len;

    ev = getenv("LD_LIBRARY_PATH");
    
    /* if we couldn't find something make up a default */
	if (!ev)
	    ev = "/usr/local/netscape;/usr/local/netscape/java/bin"; /* do we put the classes in here too? */
	
	len = strlen(ev) + 1;		/* +1 for the null */
	p = (char*) PR_MALLOC(len);
	if (p) {
	    strcpy(p, ev);
	}
	ev = p;
	}
#endif

#ifdef XP_UNIX
#if defined USE_DLFCN || defined USE_RLD
    {
	char *home;
	char *local;
	char *p=NULL;
    char * mozilla_home=NULL;
	int len;

	ev = getenv("LD_LIBRARY_PATH");
	if (!ev) {
	    ev = "/usr/lib:/lib";
	}
	home = getenv("HOME");

	/*
	** Augment the path automatically by adding in ~/.netscape and
	** /usr/local/netscape
	*/
	len = strlen(ev) + 1;		/* +1 for the null */
	if (home && home[0]) {
	    len += strlen(home) + 1;	/* +1 for the colon */
	}

	mozilla_home = getenv("MOZILLA_HOME");
	if (mozilla_home && mozilla_home[0]) {
	  len += strlen(mozilla_home) + 5 ;  /* +5 for initial : and trailing "/lib" */
	}

	local = ":/usr/local/netscape/lib/" PR_LINKER_ARCH;
	len += strlen(local);		/* already got the : */
	p = (char*) PR_MALLOC(len+50);
	if (p) {
	    strcpy(p, ev);
	    if (home) {
	        strcat(p, ":");
	        strcat(p, home);
	    }
        if (mozilla_home && mozilla_home[0]) {
          strcat(p, ":");
          strcat(p, mozilla_home); 
          strcat(p, "/lib");
        }
	    strcat(p, local);
	}   /* if (p)  */
	ev = p;
	PR_LOG(_pr_io_lm, PR_LOG_NOTICE, ("linker path '%s'", ev));

        printf("linker_path = %s\n", ev); 

    }
#else
    /* AFAIK there isn't a library path with the HP SHL interface --Rob */
    ev = strdup("");
#endif
#endif

    /*
     * If ev is NULL, we have run out of memory
     */
    _pr_currentLibPath = ev;

  exit:
    if (_pr_currentLibPath) {
        copy = strdup(_pr_currentLibPath);
    }
    PR_ExitMonitor(pr_linker_lock);
    if (!copy) {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
    }
    return copy;
}

/*
** Build library name from path, lib and extensions
*/
PR_IMPLEMENT(char*) 
PR_GetLibraryName(const char *path, const char *lib)
{
    char *fullname;

#ifdef XP_PC
    if (strstr(lib, PR_DLL_SUFFIX) == NULL)
    {
    	fullname = PR_smprintf("%s\\%s%s", path, lib, PR_DLL_SUFFIX);
    } else {
        fullname = PR_smprintf("%s\\%s", path, lib);
    }
#endif /* XP_PC */
#ifdef XP_MAC
    fullname = PR_smprintf("%s%s", path, lib);
#endif
#ifdef XP_UNIX
    if (strstr(lib, PR_DLL_SUFFIX) == NULL)
    {
        fullname = PR_smprintf("%s/lib%s%s", path, lib, PR_DLL_SUFFIX);
    } else {
        fullname = PR_smprintf("%s/%s", path, lib);
    }
#endif /* XP_UNIX */
    return fullname;
}

/*
** Free the memory allocated, for the caller, by PR_GetLibraryName
*/
PR_IMPLEMENT(void) 
PR_FreeLibraryName(char *mem)
{
    PR_smprintf_free(mem);
}

static PRLibrary* 
pr_UnlockedFindLibrary(const char *name)
{
    PRLibrary* lm = pr_loadmap;
    const char* np = strrchr(name, PR_DIRECTORY_SEPARATOR);
    np = np ? np + 1 : name;
    while (lm) {
	const char* cp = strrchr(lm->name, PR_DIRECTORY_SEPARATOR);
	cp = cp ? cp + 1 : lm->name;
#ifdef XP_PC
        /* Windows DLL names are case insensitive... */
	if (strcmpi(np, cp) == 0) 
#else
	if (strcmp(np, cp)  == 0) 
#endif
	{
	    /* found */
	    lm->refCount++;
	    PR_LOG(_pr_linker_lm, PR_LOG_MIN,
		   ("%s incr => %d (find lib)",
		    lm->name, lm->refCount));
	    return lm;
	}
	lm = lm->next;
    }
    return NULL;
}

/*
** Dynamically load a library. Only load libraries once, so scan the load
** map first.
*/
PR_IMPLEMENT(PRLibrary*) 
PR_LoadLibrary(const char *name)
{
    PRLibrary *lm;
    PRLibrary* result;

    if (!_pr_initialized) _PR_ImplicitInitialization();

    /* See if library is already loaded */
    PR_EnterMonitor(pr_linker_lock);

    result = pr_UnlockedFindLibrary(name);
    if (result != NULL) goto unlock;

    lm = PR_NEWZAP(PRLibrary);
    if (lm == NULL) goto unlock;
    lm->staticTable = NULL;

#ifdef XP_OS2  /* Why isn't all this stuff in MD code?! */
    {
        NODL_PROC *pfn;
        HMODULE h;
        UCHAR pszError[_MAX_PATH];
        ULONG ulRc = NO_ERROR;
        int first_try = 1;

        retry:
              ulRc = DosLoadModule(pszError, _MAX_PATH, (PSZ) name, &h);
      	if (ulRc != NO_ERROR) {
      	    PR_DELETE(lm);
      	    goto unlock;
      	}
      	lm->name = strdup(name);
      	lm->dlh  = h;
      	lm->next = pr_loadmap;
      	pr_loadmap = lm;
    }
#endif /* XP_OS2 */

#if defined(WIN32) || defined(WIN16)
    {
	HINSTANCE h;
    NODL_PROC *pfn;

	h = LoadLibrary(name);
	if (h < (HINSTANCE)HINSTANCE_ERROR) {
	    PR_DELETE(lm);
	    goto unlock;
	}
	lm->name = strdup(name);
	lm->dlh = h;
	lm->next = pr_loadmap;
	pr_loadmap = lm;

        /*
        ** Try to load a table of "static functions" provided by the DLL
        */

        pfn = (NODL_PROC *)GetProcAddress(h, "NODL_TABLE");
        if (pfn != NULL) {
            lm->staticTable = (*pfn)();
        }
    }
#endif /* WIN32 || WIN16 */

#if defined(XP_MAC) && GENERATINGCFM
    {
	OSErr				err;
	Ptr					main;
	CFragConnectionID	connectionID;
	Str255				errName;
	Str255				pName;
	char				cName[64];
	const char*				libName;
		
	/*
	 * Algorithm: The "name" passed in could be either a shared
	 * library name that we should look for in the normal library
	 * search paths, or a full path name to a specific library on
	 * disk.  Since the full path will always contain a ":"
	 * (shortest possible path is "Volume:File"), and since a
	 * library name can not contain a ":", we can test for the
	 * presence of a ":" to see which type of library we should load.
	 * or its a full UNIX path which we for now assume is Java
	 * enumerating all the paths (see below)
	 */
	if (strchr(name, PR_PATH_SEPARATOR) == NULL)
	{
		if (strchr(name, PR_DIRECTORY_SEPARATOR) == NULL)
	{
		/*
		 * The name did not contain a ":", so it must be a
		 * library name.  Convert the name to a Pascal string
		 * and try to find the library.
		 */
		}
		else
		{
			/* name contained a "/" which means we need to suck off the last part */
			/* of the path and pass that on the NSGetSharedLibrary */
			/* this may not be what we really want to do .. because Java could */
			/* be iterating through the whole LD path, and we'll find it if it's */
			/* anywhere on that path -- it appears that's what UNIX and the PC do */
			/* too...so we'll emulate but it could be wrong. */
			name = strrchr(name, PR_DIRECTORY_SEPARATOR) + 1;
		}
		
		PStrFromCStr(name, pName);
	
		err = NSGetSharedLibrary(pName, &connectionID, &main);
		if (err != noErr)
			goto unlock;	
		
		libName = name;
	}
	else	
	{
		/*
		 * The name did contain a ":", so it must be a full path name.
		 * Now we have to do a lot of work to convert the path name to
		 * an FSSpec (silly, since we were probably just called from the
		 * MacFE plug-in code that already knew the FSSpec and converted
		 * it to a full path just to pass to us).  First we copy out the
		 * volume name (the text leading up to the first ":"); then we
		 * separate the file name (the text following the last ":") from
		 * rest of the path.  After converting the strings to Pascal
		 * format we can call GetCatInfo to get the parent directory ID
		 * of the file, and then (finally) make an FSSpec and call
		 * GetDiskFragment.
		 */
		char* cMacPath = NULL;
		char* cFileName = NULL;
		char* position = NULL;
		CInfoPBRec pb;
		FSSpec fileSpec;
		PRUint32 index;

		/* Copy the name: we'll change it */
		cMacPath = strdup(name);	
		if (cMacPath == NULL)
			goto unlock;
			
		/* First, get the vRefNum */
		position = strchr(cMacPath, PR_PATH_SEPARATOR);
		if ((position == cMacPath) || (position == NULL))
			fileSpec.vRefNum = 0;		/* Use application relative searching */
		else
		{
			char cVolName[32];
			memset(cVolName, 0, sizeof(cVolName));
			strncpy(cVolName, cMacPath, position-cMacPath);
			fileSpec.vRefNum = GetVolumeRefNumFromName(cVolName);
		}

		/* Next, break the path and file name apart */
		index = 0;
		while (cMacPath[index] != 0)
			index++;
		while (cMacPath[index] != PR_PATH_SEPARATOR && index > 0)
			index--;
		if (index == 0 || index == strlen(cMacPath))
		{
			PR_DELETE(cMacPath);
			goto unlock;
		}
		cMacPath[index] = 0;
		cFileName = &(cMacPath[index + 1]);
		
		/* Convert the path and name into Pascal strings */
		strcpy((char*) &pName, cMacPath);
		c2pstr((char*) &pName);
		strcpy((char*) &fileSpec.name, cFileName);
		c2pstr((char*) &fileSpec.name);
		strcpy(cName, cFileName);
		PR_DELETE(cMacPath);
		cMacPath = NULL;
		
		/* Now we can look up the path on the volume */
		pb.dirInfo.ioNamePtr = pName;
		pb.dirInfo.ioVRefNum = fileSpec.vRefNum;
		pb.dirInfo.ioDrDirID = 0;
		pb.dirInfo.ioFDirIndex = 0;
		err = PBGetCatInfoSync(&pb);
		if (err != noErr)
			goto unlock;
		fileSpec.parID = pb.dirInfo.ioDrDirID;

		/* Finally, try to load the library */
		err = GetDiskFragment(&fileSpec, 0, kCFragGoesToEOF, fileSpec.name, 
						kLoadCFrag, &connectionID, &main, errName);

		libName = cName;
		if (err != noErr)
		    goto unlock;
	}
	
	lm->name = strdup(libName);
	lm->dlh = connectionID;
	lm->next = pr_loadmap;
	pr_loadmap = lm;
    }
#elif defined(XP_MAC) && !GENERATINGCFM
    {

    }
#endif

#ifdef XP_UNIX
#ifdef HAVE_DLL
    {
#if defined(USE_DLFCN)
	void *h = dlopen(name, RTLD_LAZY);
#elif defined(USE_HPSHL)
    /*
     * Shared libraries built using aCC cannot be dynamically loaded
     * with BIND_DEFERRED, so we have to use the BIND_IMMEDIATE flag.
     */
    shl_t h = shl_load(name, BIND_IMMEDIATE | DYNAMIC_PATH, 0L);
#elif defined(USE_RLD)
    NSObjectFileImage ofi;
    NSModule h = NULL;
    if (NSCreateObjectFileImageFromFile(name, &ofi)
            == NSObjectFileImageSuccess) {
        h = NSLinkModule(ofi, name, TRUE);
    }
#else
#error Configuration error
#endif
	if (!h) {
	    PR_DELETE(lm);
	    goto unlock;
	}
	lm->name = strdup(name);
	lm->dlh = h;
	lm->next = pr_loadmap;
	pr_loadmap = lm;
    }
#endif /* HAVE_DLL */
#endif /* XP_UNIX */

    lm->refCount = 1;
    result = lm;	/* success */
    PR_LOG(_pr_linker_lm, PR_LOG_MIN, ("Loaded library %s (load lib)", lm->name));

  unlock:
    if (result == NULL) {
        PR_SetError(PR_LOAD_LIBRARY_ERROR, _MD_ERRNO());
        DLLErrorInternal(_MD_ERRNO());  /* sets error text */
    }
    PR_ExitMonitor(pr_linker_lock);
    return result;
}

PR_IMPLEMENT(PRLibrary*) 
PR_FindLibrary(const char *name)
{
    PRLibrary* result;

    PR_EnterMonitor(pr_linker_lock);
    result = pr_UnlockedFindLibrary(name);
    PR_ExitMonitor(pr_linker_lock);
    return result;
}

/*
** Unload a shared library which was loaded via PR_LoadLibrary
*/
PR_IMPLEMENT(PRStatus) 
PR_UnloadLibrary(PRLibrary *lib)
{
    int result = 0;
    PRStatus status = PR_SUCCESS;

    if ((lib == 0) || (lib->refCount <= 0)) {
        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
        return PR_FAILURE;
    }

    PR_EnterMonitor(pr_linker_lock);
    if (--lib->refCount > 0) {
	PR_LOG(_pr_linker_lm, PR_LOG_MIN,
	       ("%s decr => %d",
		lib->name, lib->refCount));
	goto done;
    }
#ifdef XP_UNIX
#ifdef HAVE_DLL
#ifdef USE_DLFCN
    result = dlclose(lib->dlh);
#elif defined(USE_HPSHL)
    result = shl_unload(lib->dlh);
#elif defined(USE_RLD)
    result = NSUnLinkModule(lib->dlh, FALSE);
#else
#error Configuration error
#endif
#endif /* HAVE_DLL */
#endif /* XP_UNIX */
#ifdef XP_PC
    if (lib->dlh) {
        FreeLibrary((HINSTANCE)(lib->dlh));
        lib->dlh = (HINSTANCE)NULL;
    }
#endif  /* XP_PC */

#if defined(XP_MAC) && GENERATINGCFM
    /* Close the connection */
	CloseConnection(&(lib->dlh));
#endif

    /* unlink from library search list */
    if (pr_loadmap == lib)
	pr_loadmap = pr_loadmap->next;
    else if (pr_loadmap != NULL) {
	PRLibrary* prev = pr_loadmap;
	PRLibrary* next = pr_loadmap->next;
	while (next != NULL) {
	    if (next == lib) {
		prev->next = next->next;
		goto freeLib;
	    }
	    prev = next;
	    next = next->next;
	}
        /*
         * fail (the library is not on the _pr_loadmap list),
         * but don't wipe out an error from dlclose/shl_unload.
         */
        PR_ASSERT(!"_pr_loadmap and lib->refCount inconsistent");
        if (result == 0) {
            PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
            status = PR_FAILURE;
        }
    }
    /*
     * We free the PRLibrary structure whether dlclose/shl_unload
     * succeeds or not.
     */

  freeLib:
    PR_LOG(_pr_linker_lm, PR_LOG_MIN, ("Unloaded library %s", lib->name));
    PR_DELETE(lib->name);
    PR_DELETE(lib);
    if (result == -1) {
        PR_SetError(PR_UNLOAD_LIBRARY_ERROR, _MD_ERRNO());
        DLLErrorInternal(_MD_ERRNO());
        status = PR_FAILURE;
    }

done:
    PR_ExitMonitor(pr_linker_lock);
    return status;
}

static void* 
pr_FindSymbolInLib(PRLibrary *lm, const char *name)
{
    void *f = NULL;

    if (lm->staticTable != NULL) {
	const PRStaticLinkTable* tp;
	for (tp = lm->staticTable; tp->name; tp++) {
	    if (strcmp(name, tp->name) == 0) {
		return (void*) tp->fp;
	    }
	}
        /* 
        ** If the symbol was not found in the static table then check if
        ** the symbol was exported in the DLL... Win16 only!!
        */
#if !defined(WIN16)
        PR_SetError(PR_FIND_SYMBOL_ERROR, 0);
        return (void*)NULL;
#endif
    }
    
#ifdef XP_OS2
    DosQueryProcAddr(lm->dlh, 0, name, (PFN *) &f);
#endif  /* XP_OS2 */

#if defined(WIN32) || defined(WIN16)
    f = GetProcAddress(lm->dlh, name);
#endif  /* WIN32 || WIN16 */

#ifdef XP_MAC
    {
	Ptr			symAddr;
	CFragSymbolClass	symClass;
	Str255		pName;
			
		PStrFromCStr(name, pName);	
		
		f = (NSFindSymbol(lm->dlh, pName, &symAddr, &symClass) == noErr) ? symAddr : NULL;
	}
#endif /* XP_MAC */

#ifdef XP_UNIX
#ifdef HAVE_DLL
#ifdef USE_DLFCN
    f = dlsym(lm->dlh, name);
#elif defined(USE_HPSHL)
    if (shl_findsym(&lm->dlh, name, TYPE_PROCEDURE, &f) == -1)
	f = NULL;
#elif defined(USE_RLD)
    f = NSAddressOfSymbol(NSLookupAndBindSymbol(name));
#endif
#endif /* HAVE_DLL */
#endif /* XP_UNIX */
    if (f == NULL) {
        PR_SetError(PR_FIND_SYMBOL_ERROR, _MD_ERRNO());
        DLLErrorInternal(_MD_ERRNO());
    }
    return f;
}

/*
** Called by class loader to resolve missing native's
*/
PR_IMPLEMENT(void*) 
PR_FindSymbol(PRLibrary *lib, const char *raw_name)
{
    void *f = NULL;
#if defined(SUNOS4) || defined(WIN16)
    char *name;
#else
    const char *name;
#endif
    /*
    ** Mangle the raw symbol name in any way that is platform specific.
    */
#if defined(SUNOS4) || defined(RHAPSODY)
    /* Need a leading _ */
    name = PR_smprintf("_%s", raw_name);
#elif defined(AIX)
    /*
    ** AIX with the normal linker put's a "." in front of the symbol
    ** name.  When use "svcc" and "svld" then the "." disappears. Go
    ** figure.
    */
    name = raw_name;
#elif defined(WIN16)
    /*
    ** Win16. symbols have a leading '_'
    */
    name = PR_smprintf("_%s", raw_name);
#else
    name = raw_name;
#endif

    PR_EnterMonitor(pr_linker_lock);
    PR_ASSERT(lib != NULL);
    f = pr_FindSymbolInLib(lib, name);

#if defined(SUNOS4) || defined(WIN16)
    PR_smprintf_free(name);
#endif

    PR_ExitMonitor(pr_linker_lock);
    return f;
}

PR_IMPLEMENT(void*) 
PR_FindSymbolAndLibrary(const char *raw_name, PRLibrary* *lib)
{
    void *f = NULL;
#if defined(SUNOS4) || defined(WIN16)
    char *name;
#else
    const char *name;
#endif
    PRLibrary* lm;

    /*
    ** Mangle the raw symbol name in any way that is platform specific.
    */
#if defined(SUNOS4) || defined(RHAPSODY)
    /* Need a leading _ */
    name = PR_smprintf("_%s", raw_name);
#elif defined(AIX)
    /*
    ** AIX with the normal linker put's a "." in front of the symbol
    ** name.  When use "svcc" and "svld" then the "." disappears. Go
    ** figure.
    */
    name = raw_name;
#elif defined(WIN16)
    /*
    ** Win16. symbols have a leading '_'
    */
    name = PR_smprintf("_%s", raw_name);
#else
    name = raw_name;
#endif

    PR_EnterMonitor(pr_linker_lock);

	/* search all libraries */
	for (lm = pr_loadmap; lm != NULL; lm = lm->next) {
	    f = pr_FindSymbolInLib(lm, name);
	    if (f != NULL) {
			*lib = lm;
			lm->refCount++;
	    	PR_LOG(_pr_linker_lm, PR_LOG_MIN,
		   			("%s incr => %d (for %s)",
		    		lm->name, lm->refCount, name));
			break;
		}
	}
#if defined(SUNOS4) || defined(WIN16)
    PR_smprintf_free(name);
#endif

    PR_ExitMonitor(pr_linker_lock);
    return f;
}

/*
** Add a static library to the list of loaded libraries. If LoadLibrary
** is called with the name then we will pretend it was already loaded
*/
PR_IMPLEMENT(PRLibrary*) 
PR_LoadStaticLibrary(const char *name, const PRStaticLinkTable *slt)
{
    PRLibrary *lm=NULL;
    PRLibrary* result = NULL;

    if (!_pr_initialized) _PR_ImplicitInitialization();

    /* See if library is already loaded */
    PR_EnterMonitor(pr_linker_lock);

    /* If the lbrary is already loaded, then add the static table information... */
    result = pr_UnlockedFindLibrary(name);
    if (result != NULL) {
        PR_ASSERT( (result->staticTable == NULL) || (result->staticTable == slt) );
        result->staticTable = slt;
        goto unlock;
    }

    /* Add library to list...Mark it static */
    lm = PR_NEWZAP(PRLibrary);
    if (lm == NULL) goto unlock;

    lm->name = strdup(name);
    lm->refCount    = 1;
    lm->dlh         = pr_exe_loadmap ? pr_exe_loadmap->dlh : 0;
    lm->staticTable = slt;
    lm->next        = pr_loadmap;
    pr_loadmap      = lm;

    result = lm;	/* success */
    PR_ASSERT(lm->refCount == 1);
  unlock:
    PR_LOG(_pr_linker_lm, PR_LOG_MIN, ("Loaded library %s (static lib)", lm->name));
    PR_ExitMonitor(pr_linker_lock);
    return result;
}
