1 /* dl_aix.xs
2  *
3  * Written: 8/31/94 by Wayne Scott (wscott@ichips.intel.com)
4  *
5  *  All I did was take Jens-Uwe Mager's libdl emulation library for
6  *  AIX and merged it with the dl_dlopen.xs file to create a dynamic library
7  *  package that works for AIX.
8  *
9  *  I did change all malloc's, free's, strdup's, calloc's to use the perl
10  *  equilvant.  I also removed some stuff we will not need.  Call fini()
11  *  on startup...   It can probably be trimmed more.
12  */
13 
14 #define PERLIO_NOT_STDIO 0
15 #define PERL_EXT
16 #define PERL_IN_DL_AIX_XS
17 
18 /*
19  * On AIX 4.3 and above the emulation layer is not needed any more, and
20  * indeed if perl uses its emulation and perl is linked into apache
21  * which is supposed to use the native dlopen conflicts arise.
22  * Jens-Uwe Mager jum@helios.de
23  */
24 #ifdef USE_NATIVE_DLOPEN
25 
26 #include "EXTERN.h"
27 #include "perl.h"
28 #include "XSUB.h"
29 #include <dlfcn.h>
30 
31 #include "dlutils.c"	/* SaveError() etc	*/
32 
33 #else
34 
35 /*
36  * @(#)dlfcn.c	1.5 revision of 93/02/14  20:14:17
37  * This is an unpublished work copyright (c) 1992 Helios Software GmbH
38  * 3000 Hannover 1, Germany
39  */
40 #include "EXTERN.h"
41 #include "perl.h"
42 #include "XSUB.h"
43 
44 /* When building as a 64-bit binary on AIX, define this to get the
45  * correct structure definitions.  Also determines the field-name
46  * macros and gates some logic in readEntries().  -- Steven N. Hirsch
47  * <hirschs@btv.ibm.com> */
48 #ifdef USE_64_BIT_ALL
49 #   define __XCOFF64__
50 #   define __XCOFF32__
51 #endif
52 
53 #include <stdio.h>
54 #include <errno.h>
55 #include <string.h>
56 #include <stdlib.h>
57 #include <sys/types.h>
58 #include <sys/ldr.h>
59 #include <a.out.h>
60 #undef FREAD
61 #undef FWRITE
62 #include <ldfcn.h>
63 
64 #ifdef USE_64_BIT_ALL
65 #   define AIX_SCNHDR SCNHDR_64
66 #   define AIX_LDHDR LDHDR_64
67 #   define AIX_LDSYM LDSYM_64
68 #   define AIX_LDHDRSZ LDHDRSZ_64
69 #else
70 #   define AIX_SCNHDR SCNHDR
71 #   define AIX_LDHDR LDHDR
72 #   define AIX_LDSYM LDSYM
73 #   define AIX_LDHDRSZ LDHDRSZ
74 #endif
75 
76 /* When using Perl extensions written in C++ the longer versions
77  * of load() and unload() from libC and libC_r need to be used,
78  * otherwise statics in the extensions won't get initialized right.
79  * -- Stephanie Beals <bealzy@us.ibm.com> */
80 
81 /* Older AIX C compilers cannot deal with C++ double-slash comments in
82    the ibmcxx and/or xlC includes.  Since we only need a single file,
83    be more fine-grained about what's included <hirschs@btv.ibm.com> */
84 
85 #ifdef USE_libC /* The define comes, when it comes, from hints/aix.pl. */
86 #   define LOAD   loadAndInit
87 #   define UNLOAD terminateAndUnload
88 #   if defined(USE_vacpp_load_h)
89 #       include "/usr/vacpp/include/load.h"
90 #   elif defined(USE_ibmcxx_load_h)
91 #       include "/usr/ibmcxx/include/load.h"
92 #   elif defined(USE_xlC_load_h)
93 #       include "/usr/lpp/xlC/include/load.h"
94 #   elif defined(USE_load_h)
95 #       include "/usr/include/load.h"
96 #   endif
97 #else
98 #   define LOAD   load
99 #   define UNLOAD unload
100 #endif
101 
102 /*
103  * AIX 4.3 does remove some useful definitions from ldfcn.h. Define
104  * these here to compensate for that lossage.
105  */
106 #ifndef BEGINNING
107 # define BEGINNING SEEK_SET
108 #endif
109 #ifndef FSEEK
110 # define FSEEK(ldptr,o,p)	fseek(IOPTR(ldptr),(p==BEGINNING)?(OFFSET(ldptr) +o):o,p)
111 #endif
112 #ifndef FREAD
113 # define FREAD(p,s,n,ldptr)	fread(p,s,n,IOPTR(ldptr))
114 #endif
115 
116 #ifndef RTLD_LAZY
117 # define RTLD_LAZY 0
118 #endif
119 #ifndef RTLD_GLOBAL
120 # define RTLD_GLOBAL 0
121 #endif
122 
123 /*
124  * We simulate dlopen() et al. through a call to load. Because AIX has
125  * no call to find an exported symbol we read the loader section of the
126  * loaded module and build a list of exported symbols and their virtual
127  * address.
128  */
129 
130 typedef struct {
131 	char		*name;		/* the symbols's name */
132 	void		*addr;		/* its relocated virtual address */
133 } Export, *ExportPtr;
134 
135 /*
136  * The void * handle returned from dlopen is actually a ModulePtr.
137  */
138 typedef struct Module {
139 	struct Module	*next;
140 	char		*name;		/* module name for refcounting */
141 	int		refCnt;		/* the number of references */
142 	void		*entry;		/* entry point from load */
143 	int		nExports;	/* the number of exports found */
144 	ExportPtr	exports;	/* the array of exports */
145 } Module, *ModulePtr;
146 
147 typedef struct {
148     /*
149      * We keep a list of all loaded modules to be able to reference count
150      * duplicate dlopen's.
151      */
152     ModulePtr	x_modList;
153 
154     /*
155      * The last error from one of the dl* routines is kept in static
156      * variables here. Each error is returned only once to the caller.
157      */
158     char	x_errbuf[BUFSIZ];
159     int		x_errvalid;
160     void *	x_mainModule;
161 } my_cxtx_t;		/* this *must* be named my_cxtx_t */
162 
163 #define DL_CXT_EXTRA	/* ask for dl_cxtx to be defined in dlutils.c */
164 #include "dlutils.c"	/* SaveError() etc	*/
165 
166 #define dl_modList	(dl_cxtx.x_modList)
167 #define dl_errbuf	(dl_cxtx.x_errbuf)
168 #define dl_errvalid	(dl_cxtx.x_errvalid)
169 #define dl_mainModule	(dl_cxtx.x_mainModule)
170 
171 static void caterr(char *);
172 static int readExports(ModulePtr);
173 static void *findMain(void);
174 
175 /* these statics are ok because they're constants */
176 static char *strerror_failed   = "(strerror failed)";
177 static char *strerror_r_failed = "(strerror_r failed)";
178 
179 char *strerrorcat(char *str, int err) {
180     int strsiz = strlen(str);
181     int msgsiz;
182     char *msg;
183 
184     dTHX;
185 
186     if ((msg = strerror(err)) == 0)
187       msg = strerror_failed;
188     msgsiz = strlen(msg);		/* Note msg = buf and free() above. */
189     if (strsiz + msgsiz < BUFSIZ)	/* Do not move this after #endif. */
190       strcat(str, msg);
191 
192     return str;
193 }
194 
195 char *strerrorcpy(char *str, int err) {
196     int msgsiz;
197     char *msg;
198 
199     dTHX;
200 
201     if ((msg = strerror(err)) == 0)
202       msg = strerror_failed;
203     msgsiz = strlen(msg);	/* Note msg = buf and free() above. */
204     if (msgsiz < BUFSIZ)	/* Do not move this after #endif. */
205       strcpy(str, msg);
206 
207     return str;
208 }
209 
210 /* ARGSUSED */
211 void *dlopen(char *path, int mode)
212 {
213 	dTHX;
214 	dMY_CXT;
215 	ModulePtr mp;
216 
217 	/*
218 	 * Upon the first call register a terminate handler that will
219 	 * close all libraries.
220 	 */
221 	if (dl_mainModule == NULL) {
222 		if ((dl_mainModule = findMain()) == NULL)
223 			return NULL;
224 	}
225 	/*
226 	 * Scan the list of modules if have the module already loaded.
227 	 */
228 	for (mp = dl_modList; mp; mp = mp->next)
229 		if (strEQ(mp->name, path)) {
230 			mp->refCnt++;
231 			return mp;
232 		}
233 	Newxz(mp,1,Module);
234 	if (mp == NULL) {
235 		dl_errvalid++;
236 		strcpy(dl_errbuf, "Newz: ");
237 		strerrorcat(dl_errbuf, errno);
238 		return NULL;
239 	}
240 
241 	if ((mp->name = savepv(path)) == NULL) {
242 		dl_errvalid++;
243 		strcpy(dl_errbuf, "savepv: ");
244 		strerrorcat(dl_errbuf, errno);
245 		safefree(mp);
246 		return NULL;
247 	}
248 
249 	/*
250 	 * load should be declared load(const char *...). Thus we
251 	 * cast the path to a normal char *. Ugly.
252 	 */
253 	if ((mp->entry = (void *)LOAD((char *)path,
254 #ifdef L_LIBPATH_EXEC
255 				      L_LIBPATH_EXEC |
256 #endif
257 				      L_NOAUTODEFER,
258 				      NULL)) == NULL) {
259 	        int saverrno = errno;
260 
261 		safefree(mp->name);
262 		safefree(mp);
263 		dl_errvalid++;
264 		strcpy(dl_errbuf, "dlopen: ");
265 		strcat(dl_errbuf, path);
266 		strcat(dl_errbuf, ": ");
267 		/*
268 		 * If AIX says the file is not executable, the error
269 		 * can be further described by querying the loader about
270 		 * the last error.
271 		 */
272 		if (saverrno == ENOEXEC) {
273 			char *moreinfo[BUFSIZ/sizeof(char *)];
274 			if (loadquery(L_GETMESSAGES, moreinfo, sizeof(moreinfo)) == -1)
275 				strerrorcpy(dl_errbuf, saverrno);
276 			else {
277 				char **p;
278 				for (p = moreinfo; *p; p++)
279 					caterr(*p);
280 			}
281 		} else
282 			strerrorcat(dl_errbuf, saverrno);
283 		return NULL;
284 	}
285 	mp->refCnt = 1;
286 	mp->next = dl_modList;
287 	dl_modList = mp;
288 	/*
289 	 * Assume anonymous exports come from the module this dlopen
290 	 * is linked into, that holds true as long as dlopen and all
291 	 * of the perl core are in the same shared object. Also bind
292 	 * against the main part, in the case a perl is not the main
293 	 * part, e.g mod_perl as DSO in Apache so perl modules can
294 	 * also reference Apache symbols.
295 	 */
296 	if (loadbind(0, (void *)dlopen, mp->entry) == -1 ||
297 	    loadbind(0, dl_mainModule, mp->entry)) {
298 	        int saverrno = errno;
299 
300 		dlclose(mp);
301 		dl_errvalid++;
302 		strcpy(dl_errbuf, "loadbind: ");
303 		strerrorcat(dl_errbuf, saverrno);
304 		return NULL;
305 	}
306 	if (readExports(mp) == -1) {
307 		dlclose(mp);
308 		return NULL;
309 	}
310 	return mp;
311 }
312 
313 /*
314  * Attempt to decipher an AIX loader error message and append it
315  * to our static error message buffer.
316  */
317 static void caterr(char *s)
318 {
319 	dTHX;
320 	dMY_CXT;
321 	char *p = s;
322 
323 	while (*p >= '0' && *p <= '9')
324 		p++;
325 	switch(atoi(s)) {
326 	case L_ERROR_TOOMANY:
327 		strcat(dl_errbuf, "too many errors");
328 		break;
329 	case L_ERROR_NOLIB:
330 		strcat(dl_errbuf, "can't load library");
331 		strcat(dl_errbuf, p);
332 		break;
333 	case L_ERROR_UNDEF:
334 		strcat(dl_errbuf, "can't find symbol");
335 		strcat(dl_errbuf, p);
336 		break;
337 	case L_ERROR_RLDBAD:
338 		strcat(dl_errbuf, "bad RLD");
339 		strcat(dl_errbuf, p);
340 		break;
341 	case L_ERROR_FORMAT:
342 		strcat(dl_errbuf, "bad exec format in");
343 		strcat(dl_errbuf, p);
344 		break;
345 	case L_ERROR_ERRNO:
346 		strerrorcat(dl_errbuf, atoi(++p));
347 		break;
348 	default:
349 		strcat(dl_errbuf, s);
350 		break;
351 	}
352 }
353 
354 void *dlsym(void *handle, const char *symbol)
355 {
356 	dTHX;
357 	dMY_CXT;
358 	ModulePtr mp = (ModulePtr)handle;
359 	ExportPtr ep;
360 	int i;
361 
362 	/*
363 	 * Could speed up search, but I assume that one assigns
364 	 * the result to function pointers anyways.
365 	 */
366 	for (ep = mp->exports, i = mp->nExports; i; i--, ep++)
367 		if (strEQ(ep->name, symbol))
368 			return ep->addr;
369 	dl_errvalid++;
370 	strcpy(dl_errbuf, "dlsym: undefined symbol ");
371 	strcat(dl_errbuf, symbol);
372 	return NULL;
373 }
374 
375 char *dlerror(void)
376 {
377 	dTHX;
378 	dMY_CXT;
379 	if (dl_errvalid) {
380 		dl_errvalid = 0;
381 		return dl_errbuf;
382 	}
383 	return NULL;
384 }
385 
386 int dlclose(void *handle)
387 {
388 	dTHX;
389 	dMY_CXT;
390 	ModulePtr mp = (ModulePtr)handle;
391 	int result;
392 	ModulePtr mp1;
393 
394 	if (--mp->refCnt > 0)
395 		return 0;
396 	result = UNLOAD(mp->entry);
397 	if (result == -1) {
398 		dl_errvalid++;
399 		strerrorcpy(dl_errbuf, errno);
400 	}
401 	if (mp->exports) {
402 		ExportPtr ep;
403 		int i;
404 		for (ep = mp->exports, i = mp->nExports; i; i--, ep++)
405 			if (ep->name)
406 				safefree(ep->name);
407 		safefree(mp->exports);
408 	}
409 	if (mp == dl_modList)
410 		dl_modList = mp->next;
411 	else {
412 		for (mp1 = dl_modList; mp1; mp1 = mp1->next)
413 			if (mp1->next == mp) {
414 				mp1->next = mp->next;
415 				break;
416 			}
417 	}
418 	safefree(mp->name);
419 	safefree(mp);
420 	return result;
421 }
422 
423 /* Added by Wayne Scott
424  * This is needed because the ldopen system call calls
425  * calloc to allocated a block of date.  The ldclose call calls free.
426  * Without this we get this system calloc and perl's free, resulting
427  * in a "Bad free" message.  This way we always use perl's malloc.
428  */
429 void *calloc(size_t ne, size_t sz)
430 {
431   void *out;
432 
433   out = (void *) safemalloc(ne*sz);
434   memzero(out, ne*sz);
435   return(out);
436 }
437 
438 /*
439  * Build the export table from the XCOFF .loader section.
440  */
441 static int readExports(ModulePtr mp)
442 {
443 	dTHX;
444 	dMY_CXT;
445 	LDFILE *ldp = NULL;
446 	AIX_SCNHDR sh;
447 	AIX_LDHDR *lhp;
448 	char *ldbuf;
449 	AIX_LDSYM *ls;
450 	int i;
451 	ExportPtr ep;
452 
453 	if ((ldp = ldopen(mp->name, ldp)) == NULL) {
454 		struct ld_info *lp;
455 		char *buf;
456 		int size = 4*1024;
457 		if (errno != ENOENT) {
458 			dl_errvalid++;
459 			strcpy(dl_errbuf, "readExports: ");
460 			strerrorcat(dl_errbuf, errno);
461 			return -1;
462 		}
463 		/*
464 		 * The module might be loaded due to the LIBPATH
465 		 * environment variable. Search for the loaded
466 		 * module using L_GETINFO.
467 		 */
468 		if ((buf = safemalloc(size)) == NULL) {
469 			dl_errvalid++;
470 			strcpy(dl_errbuf, "readExports: ");
471 			strerrorcat(dl_errbuf, errno);
472 			return -1;
473 		}
474 		while ((i = loadquery(L_GETINFO, buf, size)) == -1 && errno == ENOMEM) {
475 			safefree(buf);
476 			size += 4*1024;
477 			if ((buf = safemalloc(size)) == NULL) {
478 				dl_errvalid++;
479 				strcpy(dl_errbuf, "readExports: ");
480 				strerrorcat(dl_errbuf, errno);
481 				return -1;
482 			}
483 		}
484 		if (i == -1) {
485 			dl_errvalid++;
486 			strcpy(dl_errbuf, "readExports: ");
487 			strerrorcat(dl_errbuf, errno);
488 			safefree(buf);
489 			return -1;
490 		}
491 		/*
492 		 * Traverse the list of loaded modules. The entry point
493 		 * returned by LOAD() does actually point to the data
494 		 * segment origin.
495 		 */
496 		lp = (struct ld_info *)buf;
497 		while (lp) {
498 			if (lp->ldinfo_dataorg == mp->entry) {
499 				ldp = ldopen(lp->ldinfo_filename, ldp);
500 				break;
501 			}
502 			if (lp->ldinfo_next == 0)
503 				lp = NULL;
504 			else
505 				lp = (struct ld_info *)((char *)lp + lp->ldinfo_next);
506 		}
507 		safefree(buf);
508 		if (!ldp) {
509 			dl_errvalid++;
510 			strcpy(dl_errbuf, "readExports: ");
511 			strerrorcat(dl_errbuf, errno);
512 			return -1;
513 		}
514 	}
515 #ifdef USE_64_BIT_ALL
516 	if (TYPE(ldp) != U803XTOCMAGIC) {
517 #else
518 	if (TYPE(ldp) != U802TOCMAGIC) {
519 #endif
520 		dl_errvalid++;
521 		strcpy(dl_errbuf, "readExports: bad magic");
522 		while(ldclose(ldp) == FAILURE)
523 			;
524 		return -1;
525 	}
526 	if (ldnshread(ldp, _LOADER, &sh) != SUCCESS) {
527 		dl_errvalid++;
528 		strcpy(dl_errbuf, "readExports: cannot read loader section header");
529 		while(ldclose(ldp) == FAILURE)
530 			;
531 		return -1;
532 	}
533 	/*
534 	 * We read the complete loader section in one chunk, this makes
535 	 * finding long symbol names residing in the string table easier.
536 	 */
537 	if ((ldbuf = (char *)safemalloc(sh.s_size)) == NULL) {
538 		dl_errvalid++;
539 		strcpy(dl_errbuf, "readExports: ");
540 		strerrorcat(dl_errbuf, errno);
541 		while(ldclose(ldp) == FAILURE)
542 			;
543 		return -1;
544 	}
545 	if (FSEEK(ldp, sh.s_scnptr, BEGINNING) != OKFSEEK) {
546 		dl_errvalid++;
547 		strcpy(dl_errbuf, "readExports: cannot seek to loader section");
548 		safefree(ldbuf);
549 		while(ldclose(ldp) == FAILURE)
550 			;
551 		return -1;
552 	}
553 /* This first case is a hack, since it assumes that the 3rd parameter to
554    FREAD is 1. See the redefinition of FREAD above to see how this works. */
555 	if (FREAD(ldbuf, sh.s_size, 1, ldp) != 1) {
556 		dl_errvalid++;
557 		strcpy(dl_errbuf, "readExports: cannot read loader section");
558 		safefree(ldbuf);
559 		while(ldclose(ldp) == FAILURE)
560 			;
561 		return -1;
562 	}
563 	lhp = (AIX_LDHDR *)ldbuf;
564 	ls = (AIX_LDSYM *)(ldbuf+AIX_LDHDRSZ);
565 	/*
566 	 * Count the number of exports to include in our export table.
567 	 */
568 	for (i = lhp->l_nsyms; i; i--, ls++) {
569 		if (!LDR_EXPORT(*ls))
570 			continue;
571 		mp->nExports++;
572 	}
573 	Newxz(mp->exports, mp->nExports, Export);
574 	if (mp->exports == NULL) {
575 		dl_errvalid++;
576 		strcpy(dl_errbuf, "readExports: ");
577 		strerrorcat(dl_errbuf, errno);
578 		safefree(ldbuf);
579 		while(ldclose(ldp) == FAILURE)
580 			;
581 		return -1;
582 	}
583 	/*
584 	 * Fill in the export table. All entries are relative to
585 	 * the entry point we got from load.
586 	 */
587 	ep = mp->exports;
588 	ls = (AIX_LDSYM *)(ldbuf+AIX_LDHDRSZ);
589 	for (i = lhp->l_nsyms; i; i--, ls++) {
590 		char *symname;
591 		if (!LDR_EXPORT(*ls))
592 			continue;
593 #ifndef USE_64_BIT_ALL
594 		if (ls->l_zeroes == 0)
595 #endif
596 			symname = ls->l_offset+lhp->l_stoff+ldbuf;
597 #ifndef USE_64_BIT_ALL
598 		else
599 			symname = ls->l_name;
600 #endif
601 		ep->name = savepv(symname);
602 		ep->addr = (void *)((unsigned long)mp->entry + ls->l_value);
603 		ep++;
604 	}
605 	safefree(ldbuf);
606 	while(ldclose(ldp) == FAILURE)
607 		;
608 	return 0;
609 }
610 
611 /*
612  * Find the main modules entry point. This is used as export pointer
613  * for loadbind() to be able to resolve references to the main part.
614  */
615 static void * findMain(void)
616 {
617 	dTHX;
618 	dMY_CXT;
619 	struct ld_info *lp;
620 	char *buf;
621 	int size = 4*1024;
622 	int i;
623 	void *ret;
624 
625 	if ((buf = safemalloc(size)) == NULL) {
626 		dl_errvalid++;
627 		strcpy(dl_errbuf, "findMain: ");
628 		strerrorcat(dl_errbuf, errno);
629 		return NULL;
630 	}
631 	while ((i = loadquery(L_GETINFO, buf, size)) == -1 && errno == ENOMEM) {
632 		safefree(buf);
633 		size += 4*1024;
634 		if ((buf = safemalloc(size)) == NULL) {
635 			dl_errvalid++;
636 			strcpy(dl_errbuf, "findMain: ");
637 			strerrorcat(dl_errbuf, errno);
638 			return NULL;
639 		}
640 	}
641 	if (i == -1) {
642 		dl_errvalid++;
643 		strcpy(dl_errbuf, "findMain: ");
644 		strerrorcat(dl_errbuf, errno);
645 		safefree(buf);
646 		return NULL;
647 	}
648 	/*
649 	 * The first entry is the main module. The entry point
650 	 * returned by load() does actually point to the data
651 	 * segment origin.
652 	 */
653 	lp = (struct ld_info *)buf;
654 	ret = lp->ldinfo_dataorg;
655 	safefree(buf);
656 	return ret;
657 }
658 #endif /* USE_NATIVE_DLOPEN */
659 
660 /* dl_dlopen.xs
661  *
662  * Platform:	SunOS/Solaris, possibly others which use dlopen.
663  * Author:	Paul Marquess (Paul.Marquess@btinternet.com)
664  * Created:	10th July 1994
665  *
666  * Modified:
667  * 15th July 1994   - Added code to explicitly save any error messages.
668  * 3rd August 1994  - Upgraded to v3 spec.
669  * 9th August 1994  - Changed to use IV
670  * 10th August 1994 - Tim Bunce: Added RTLD_LAZY, switchable debugging,
671  *                    basic FreeBSD support, removed ClearError
672  *
673  */
674 
675 /* Porting notes:
676 
677 	see dl_dlopen.xs
678 
679 */
680 
681 static void
682 dl_private_init(pTHX)
683 {
684     (void)dl_generic_private_init(aTHX);
685 }
686 
687 MODULE = DynaLoader     PACKAGE = DynaLoader
688 
689 BOOT:
690     (void)dl_private_init(aTHX);
691 
692 
693 void
694 dl_load_file(filename, flags=0)
695 	char *	filename
696 	int	flags
697         PREINIT:
698         void *retv;
699 	PPCODE:
700 	DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_load_file(%s,%x):\n", filename,flags));
701 	if (flags & 0x01)
702 	    Perl_warn(aTHX_ "Can't make loaded symbols global on this platform while loading %s",filename);
703 	retv = dlopen(filename, RTLD_GLOBAL|RTLD_LAZY) ;
704 	DLDEBUG(2,PerlIO_printf(Perl_debug_log, " libref=%x\n", retv));
705 	ST(0) = sv_newmortal() ;
706 	if (retv == NULL)
707 	    SaveError(aTHX_ "%s",dlerror()) ;
708 	else
709 	    sv_setiv( ST(0), PTR2IV(retv) );
710         XSRETURN(1);
711 
712 int
713 dl_unload_file(libref)
714     void *	libref
715   CODE:
716     DLDEBUG(1,PerlIO_printf(Perl_debug_log, "dl_unload_file(%lx):\n", libref));
717     RETVAL = (dlclose(libref) == 0 ? 1 : 0);
718     if (!RETVAL)
719         SaveError(aTHX_ "%s", dlerror()) ;
720     DLDEBUG(2,PerlIO_printf(Perl_debug_log, " retval = %d\n", RETVAL));
721   OUTPUT:
722     RETVAL
723 
724 void
725 dl_find_symbol(libhandle, symbolname, ign_err=0)
726 	void *		libhandle
727 	char *		symbolname
728         int	        ign_err
729 	PREINIT:
730         void *retv;
731         CODE:
732 	DLDEBUG(2,PerlIO_printf(Perl_debug_log, "dl_find_symbol(handle=%x, symbol=%s)\n",
733 		libhandle, symbolname));
734 	retv = dlsym(libhandle, symbolname);
735 	DLDEBUG(2,PerlIO_printf(Perl_debug_log, "  symbolref = %x\n", retv));
736 	ST(0) = sv_newmortal();
737 	if (retv == NULL) {
738             if (!ign_err)
739 	        SaveError(aTHX_ "%s", dlerror());
740 	} else
741 	    sv_setiv( ST(0), PTR2IV(retv));
742 
743 
744 void
745 dl_undef_symbols()
746 	CODE:
747 
748 
749 
750 # These functions should not need changing on any platform:
751 
752 void
753 dl_install_xsub(perl_name, symref, filename="$Package")
754     char *	perl_name
755     void *	symref
756     const char *	filename
757     CODE:
758     DLDEBUG(2,PerlIO_printf(Perl_debug_log, "dl_install_xsub(name=%s, symref=%x)\n",
759 	perl_name, symref));
760     ST(0) = sv_2mortal(newRV((SV*)newXS_flags(perl_name,
761 					      (void(*)(pTHX_ CV *))symref,
762 					      filename, NULL,
763 					      XS_DYNAMIC_FILENAME)));
764 
765 
766 SV *
767 dl_error()
768     CODE:
769     dMY_CXT;
770     RETVAL = newSVsv(MY_CXT.x_dl_last_error);
771     OUTPUT:
772     RETVAL
773 
774 #if defined(USE_ITHREADS)
775 
776 void
777 CLONE(...)
778     CODE:
779     MY_CXT_CLONE;
780 
781     PERL_UNUSED_VAR(items);
782 
783     /* MY_CXT_CLONE just does a memcpy on the whole structure, so to avoid
784      * using Perl variables that belong to another thread, we create our
785      * own for this thread.
786      */
787     MY_CXT.x_dl_last_error = newSVpvs("");
788 
789 #endif
790 
791 # end.
792