xref: /illumos-gate/usr/src/cmd/sgs/rtld/common/external.c (revision 04427e3bf236c18cc532680b957267ee70b1037d)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright 2014 Garrett D'Amore <garrett@damore.org>
25  * Copyright 2016 Joyent, Inc.
26  */
27 
28 /*
29  * Implementation of all external interfaces between ld.so.1 and libc.
30  *
31  * This file started as a set of routines that provided synchronization and
32  * locking operations using calls to libthread.  libthread has merged with libc
33  * under the Unified Process Model (UPM), and things have gotten a lot simpler.
34  * This file continues to establish and redirect various events within ld.so.1
35  * to interfaces within libc.
36  *
37  * Until libc is loaded and relocated, any external interfaces are captured
38  * locally.  Each link-map list maintains its own set of external vectors, as
39  * each link-map list typically provides its own libc.  Although this per-link-
40  * map list vectoring provides a degree of flexibility, there is a protocol
41  * expected when calling various libc interfaces.
42  *
43  * i.	Any new alternative link-map list should call CI_THRINIT, and then call
44  *	CI_TLS_MODADD to register any TLS for each object of that link-map list
45  *	(this item is labeled i. as auditors can be the first objects loaded,
46  *	and they exist on their own lik-map list).
47  *
48  * ii.	For the primary link-map list, CI_TLS_STATMOD must be called first to
49  *	register any static TLS.  This routine is called regardless of there
50  *	being any TLS, as this routine also establishes the link-map list as the
51  *	primary list and fixes the association of uberdata).  CI_THRINIT should
52  *	then be called.
53  *
54  * iii.	Any objects added to an existing link-map list (primary or alternative)
55  *	should call CI_TLS_MODADD to register any additional TLS.
56  *
57  * These events are established by:
58  *
59  * i.	Typically, libc is loaded as part of the primary dependencies of any
60  *	link-map list (since the Unified Process Model (UPM), libc can't be
61  *	lazily loaded).  To minimize the possibility of loading and registering
62  *	objects, and then tearing them down (because of a relocation error),
63  *	external vectors are established as part of load_completion().  This
64  *	routine is called on completion of any operation that can cause objects
65  *	to be loaded.  This point of control insures the objects have been fully
66  *	analyzed and relocated, and moved to their controlling link-map list.
67  *	The external vectors are established prior to any .inits being fired.
68  *
69  * ii.	Calls to CI_THRINIT, and CI_TLS_MODADD also occur as part of
70  *	load_completion().  CI_THRINIT is only called once for each link-map
71  *	control list.
72  *
73  * iii.	Calls to CI_TLS_STATMOD, and CI_THRINIT occur for the primary link-map
74  *	list in the final stages of setup().
75  *
76  * The interfaces provide by libc can be divided into two families.  The first
77  * family consists of those interfaces that should be called from the link-map
78  * list.  It's possible that these interfaces convey state concerning the
79  * link-map list they are part of:
80  *
81  *	CI_ATEXIT
82  *	CI TLS_MODADD
83  *	CI_TLS_MODREM
84  *	CI_TLS_STATMOD
85  *	CI_THRINIT
86  *
87  * The second family are global in nature, that is, the link-map list from
88  * which they are called provides no state information.  In fact, for
89  * CI_BIND_GUARD, the calling link-map isn't even known.  The link-map can only
90  * be deduced after ld.so.1's global lock has been obtained.  Therefore, the
91  * following interfaces are also maintained as global:
92  *
93  *	CI_LCMESSAGES
94  *	CI_BIND_GUARD
95  *	CI_BIND_CLEAR
96  *	CI_THR_SELF
97  *
98  * Note, it is possible that these global interfaces are obtained from an
99  * alternative link-map list that gets torn down because of a processing
100  * failure (unlikely, because the link-map list components must be analyzed
101  * and relocated prior to load_completion(), but perhaps the tear down is still
102  * a possibility).  Thus the global interfaces may have to be replaced.  Once
103  * the interfaces have been obtained from the primary link-map, they can
104  * remain fixed, as the primary link-map isn't going to go anywhere.
105  *
106  * The last wrinkle in the puzzle is what happens if an alternative link-map
107  * is loaded with no libc dependency?  In this case, the alternative objects
108  * can not call CI_THRINIT, can not be allowed to use TLS, and will not receive
109  * any atexit processing.
110  *
111  * The history of these external interfaces is defined by their version:
112  *
113  * TI_VERSION == 1
114  *	Under this model libthread provided rw_rwlock/rw_unlock, through which
115  *	all rt_mutex_lock/rt_mutex_unlock calls were vectored.
116  *	Under libc/libthread these interfaces provided _sigon/_sigoff (unlike
117  *	lwp/libthread that provided signal blocking via bind_guard/bind_clear).
118  *
119  * TI_VERSION == 2
120  *	Under this model only libthreads bind_guard/bind_clear and thr_self
121  *	interfaces were used.  Both libthreads blocked signals under the
122  *	bind_guard/bind_clear interfaces.   Lower level locking is derived
123  *	from internally bound _lwp_ interfaces.  This removes recursive
124  *	problems encountered when obtaining locking interfaces from libthread.
125  *	The use of mutexes over reader/writer locks also enables the use of
126  *	condition variables for controlling thread concurrency (allows access
127  *	to objects only after their .init has completed).
128  *
129  * NOTE, the TI_VERSION indicated the ti_interface version number, where the
130  * ti_interface was a large vector of functions passed to both libc (to override
131  * the thread stub interfaces) and ld.so.1.  ld.so.1 used only a small subset of
132  * these interfaces.
133  *
134  * CI_VERSION == 1
135  *	Introduced with CI_VERSION & CI_ATEXIT
136  *
137  * CI_VERSION == 2 (Solaris 8 update 2).
138  *	Added support for CI_LCMESSAGES
139  *
140  * CI_VERSION == 3 (Solaris 9).
141  *	Added the following versions to the CI table:
142  *
143  *		CI_BIND_GUARD, CI_BIND_CLEAR, CI_THR_SELF
144  *		CI_TLS_MODADD, CI_TLS_MOD_REMOVE, CI_TLS_STATMOD
145  *
146  *	This version introduced the DT_SUNW_RTLDINFO structure as a mechanism
147  *	to handshake with ld.so.1.
148  *
149  * CI_VERSION == 4 (Solaris 10).
150  *	Added the CI_THRINIT handshake as part of the libc/libthread unified
151  *	process model.  libc now initializes the current thread pointer from
152  *	this interface (and no longer relies on the INITFIRST flag - which
153  *	others have started to camp out on).
154  *
155  * CI_VERSION == 5 (Solaris 11).
156  *	Use of "protected" references within libc, so that symbols are
157  *	pre-bound, and don't require ld.so.1 binding.  This implementation
158  *	protects libc's critical regions from being vectored to auditors.
159  *
160  * CI_VERSION == 6 (Solaris 11).
161  *	Added the CI_CRITICAL handshake, to allow "mem*" family to be reexposed
162  *	as "global", and thus be redirected to auxiliary filters.
163  *
164  * Release summary:
165  *
166  *	Solaris 8	CI_ATEXIT via _ld_libc()
167  *			TI_* via _ld_concurrency()
168  *
169  *	Solaris 9	CI_ATEXIT and CI_LCMESSAGES via _ld_libc()
170  *			CI_* via RTLDINFO and _ld_libc()  - new libthread
171  *			TI_* via _ld_concurrency()  - old libthread
172  *
173  *	Solaris 10	CI_ATEXIT and CI_LCMESSAGES via _ld_libc()
174  *			CI_* via RTLDINFO and _ld_libc()  - new libthread
175  */
176 
177 #include <sys/debug.h>
178 #include <synch.h>
179 #include <signal.h>
180 #include <thread.h>
181 #include <synch.h>
182 #include <strings.h>
183 #include <stdio.h>
184 #include <libintl.h>
185 #include <debug.h>
186 #include <libc_int.h>
187 #include "_elf.h"
188 #include "_rtld.h"
189 
190 /*
191  * This interface provides the unified process model communication between
192  * ld.so.1 and libc.  This interface can be called a number of times:
193  *
194  *   -	Initially, this interface is called to process RTLDINFO.  This data
195  *	structure is typically provided by libc, and contains the address of
196  *	libc interfaces that must be called to initialize threads information.
197  *
198  *   -	_ld_libc(), this interface can also be called by libc at process
199  *	initialization, after libc has been loaded and relocated, but before
200  *	control has been passed to any user code (.init's or main()).  This
201  *	call provides additional libc interface information that ld.so.1 must
202  *	call during process execution.
203  *
204  *   -	_ld_libc() can also be called by libc during process execution to
205  * 	re-establish interfaces such as the locale.
206  */
207 static void
208 get_lcinterface(Rt_map *lmp, Lc_interface *funcs)
209 {
210 	int		threaded = 0, entry = 0, tag;
211 	Lm_list		*lml;
212 	Lc_desc		*lcp;
213 
214 	if ((lmp == NULL) || (funcs == NULL))
215 		return;
216 
217 	/*
218 	 * Once the process is active, ensure we grab a lock.
219 	 */
220 	if (rtld_flags & RT_FL_APPLIC)
221 		entry = enter(0);
222 
223 	lml = LIST(lmp);
224 	lcp = &lml->lm_lcs[0];
225 
226 	DBG_CALL(Dbg_util_nl(lml, DBG_NL_STD));
227 
228 	for (tag = funcs->ci_tag; tag; tag = (++funcs)->ci_tag) {
229 		char	*gptr;
230 		char	*lptr = funcs->ci_un.ci_ptr;
231 
232 		DBG_CALL(Dbg_util_lcinterface(lmp, tag, lptr));
233 
234 		if (tag >= CI_MAX)
235 			continue;
236 
237 		/*
238 		 * Maintain all interfaces on a per-link-map basis.  Note, for
239 		 * most interfaces, only the first interface is used for any
240 		 * link-map list.  This prevents accidents with developers who
241 		 * manage to load two different versions of libc.
242 		 */
243 		if ((lcp[tag].lc_lmp) &&
244 		    (tag != CI_LCMESSAGES) && (tag != CI_VERSION)) {
245 			DBG_CALL(Dbg_unused_lcinterface(lmp,
246 			    lcp[tag].lc_lmp, tag));
247 			continue;
248 		}
249 
250 		lcp[tag].lc_un.lc_ptr = lptr;
251 		lcp[tag].lc_lmp = lmp;
252 
253 		gptr = glcs[tag].lc_un.lc_ptr;
254 
255 		/*
256 		 * Process any interfaces that must be maintained on a global
257 		 * basis.
258 		 */
259 		switch (tag) {
260 		case CI_ATEXIT:
261 			break;
262 
263 		case CI_LCMESSAGES:
264 			/*
265 			 * At startup, ld.so.1 can establish a locale from one
266 			 * of the locale family of environment variables (see
267 			 * ld_str_env() and readenv_user()).  During process
268 			 * execution the locale can also be changed by the user.
269 			 * This interface is called from libc should the locale
270 			 * be modified.  Presently, only one global locale is
271 			 * maintained for all link-map lists, and only objects
272 			 * on the primrary link-map may change this locale.
273 			 */
274 			if ((lml->lm_flags & LML_FLG_BASELM) &&
275 			    ((gptr == NULL) || (strcmp(gptr, lptr) != 0))) {
276 				/*
277 				 * If we've obtained a message locale (typically
278 				 * supplied via libc's setlocale()), then
279 				 * register the locale for use in dgettext() so
280 				 * as to reestablish the locale for ld.so.1's
281 				 * messages.
282 				 */
283 				if (gptr) {
284 					free((void *)gptr);
285 					rtld_flags |= RT_FL_NEWLOCALE;
286 				}
287 				glcs[tag].lc_un.lc_ptr = strdup(lptr);
288 
289 				/*
290 				 * Clear any cached messages.
291 				 */
292 				bzero(err_strs, sizeof (err_strs));
293 				nosym_str = NULL;
294 			}
295 			break;
296 
297 		case CI_BIND_GUARD:
298 		case CI_BIND_CLEAR:
299 		case CI_THR_SELF:
300 		case CI_CRITICAL:
301 			/*
302 			 * If the global vector is unset, or this is the primary
303 			 * link-map, set the global vector.
304 			 */
305 			if ((gptr == NULL) || (lml->lm_flags & LML_FLG_BASELM))
306 				glcs[tag].lc_un.lc_ptr = lptr;
307 
308 			/* FALLTHROUGH */
309 
310 		case CI_TLS_MODADD:
311 		case CI_TLS_MODREM:
312 		case CI_TLS_STATMOD:
313 		case CI_THRINIT:
314 			threaded++;
315 			break;
316 
317 		case CI_VERSION:
318 			if ((rtld_flags2 & RT_FL2_RTLDSEEN) == 0) {
319 				Aliste	idx;
320 				Lm_list	*lml2;
321 				int	version;
322 
323 				rtld_flags2 |= RT_FL2_RTLDSEEN;
324 
325 				version = funcs->ci_un.ci_val;
326 #if defined(CI_V_FIVE)
327 				if (version >= CI_V_FIVE) {
328 					thr_flg_nolock = THR_FLG_NOLOCK;
329 					thr_flg_reenter = THR_FLG_REENTER;
330 				}
331 #endif
332 				if (version < CI_V_FOUR)
333 					break;
334 
335 				rtld_flags2 |= RT_FL2_UNIFPROC;
336 
337 				/*
338 				 * We might have seen an auditor which is not
339 				 * dependent on libc.  Such an auditor's link
340 				 * map list has LML_FLG_HOLDLOCK set.  This
341 				 * lock needs to be dropped.  Refer to
342 				 * audit_setup() in audit.c.
343 				 */
344 				if ((rtld_flags2 & RT_FL2_HASAUDIT) == 0)
345 					break;
346 
347 				/*
348 				 * Yes, we did.  Take care of them.
349 				 */
350 				for (APLIST_TRAVERSE(dynlm_list, idx, lml2)) {
351 					Rt_map *map = (Rt_map *)lml2->lm_head;
352 
353 					if (FLAGS(map) & FLG_RT_AUDIT) {
354 						lml2->lm_flags &=
355 						    ~LML_FLG_HOLDLOCK;
356 					}
357 				}
358 			}
359 			break;
360 
361 		default:
362 			break;
363 		}
364 	}
365 
366 	if (threaded) {
367 		/*
368 		 * If a version of libc gives us only a subset of the TLS
369 		 * interfaces, it's confused and we discard the whole lot.
370 		 */
371 		if ((lcp[CI_TLS_MODADD].lc_un.lc_func &&
372 		    lcp[CI_TLS_MODREM].lc_un.lc_func &&
373 		    lcp[CI_TLS_STATMOD].lc_un.lc_func) == NULL) {
374 			lcp[CI_TLS_MODADD].lc_un.lc_func = NULL;
375 			lcp[CI_TLS_MODREM].lc_un.lc_func = NULL;
376 			lcp[CI_TLS_STATMOD].lc_un.lc_func = NULL;
377 		}
378 
379 		/*
380 		 * Indicate that we're now thread capable.
381 		 */
382 		if ((lml->lm_flags & LML_FLG_RTLDLM) == 0)
383 			rtld_flags |= RT_FL_THREADS;
384 	}
385 
386 	if (entry)
387 		leave(lml, 0);
388 }
389 
390 /*
391  * At this point we know we have a set of objects that have been fully analyzed
392  * and relocated.  Prior to the next major step of running .init sections (ie.
393  * running user code), retrieve any RTLDINFO interfaces.
394  */
395 int
396 rt_get_extern(Lm_list *lml, Rt_map *lmp)
397 {
398 	if (lml->lm_rti) {
399 		Aliste		idx;
400 		Rti_desc	*rti;
401 
402 		for (ALIST_TRAVERSE(lml->lm_rti, idx, rti))
403 			get_lcinterface(rti->rti_lmp, rti->rti_info);
404 
405 		free(lml->lm_rti);
406 		lml->lm_rti = 0;
407 	}
408 
409 	/*
410 	 * Perform some sanity checks.  If we have TLS requirements we better
411 	 * have the associated external interfaces.
412 	 */
413 	if (lml->lm_tls &&
414 	    (lml->lm_lcs[CI_TLS_STATMOD].lc_un.lc_func == NULL)) {
415 		eprintf(lml, ERR_FATAL, MSG_INTL(MSG_TLS_NOSUPPORT),
416 		    NAME(lmp));
417 		return (0);
418 	}
419 	return (1);
420 }
421 
422 /*
423  * Provide an interface for libc to communicate additional interface
424  * information.
425  */
426 void
427 _ld_libc(void *ptr)
428 {
429 	get_lcinterface(_caller(caller(), CL_EXECDEF), (Lc_interface *)ptr);
430 }
431 
432 static int	bindmask = 0;
433 
434 int
435 rt_bind_guard(int flags)
436 {
437 	int	(*fptr)(int);
438 	int	bindflag;
439 
440 	if ((fptr = glcs[CI_BIND_GUARD].lc_un.lc_func) != NULL) {
441 		return ((*fptr)(flags));
442 	} else {
443 		bindflag = (flags & THR_FLG_RTLD);
444 		if ((bindflag & bindmask) == 0) {
445 			bindmask |= bindflag;
446 			return (1);
447 		}
448 		return (0);
449 	}
450 }
451 
452 int
453 rt_bind_clear(int flags)
454 {
455 	int	(*fptr)(int);
456 	int	bindflag;
457 
458 	if ((fptr = glcs[CI_BIND_CLEAR].lc_un.lc_func) != NULL) {
459 		return ((*fptr)(flags));
460 	} else {
461 		bindflag = (flags & THR_FLG_RTLD);
462 		if (bindflag == 0)
463 			return (bindmask);
464 		else {
465 			bindmask &= ~bindflag;
466 			return (0);
467 		}
468 	}
469 }
470 
471 /*
472  * Make sure threads have been initialized.  This interface is called once for
473  * each link-map list.
474  */
475 void
476 rt_thr_init(Lm_list *lml)
477 {
478 	void	(*fptr)(void);
479 
480 	if ((fptr =
481 	    (void (*)())lml->lm_lcs[CI_THRINIT].lc_un.lc_func) != NULL) {
482 		lml->lm_lcs[CI_THRINIT].lc_un.lc_func = NULL;
483 
484 		leave(lml, thr_flg_reenter);
485 		(*fptr)();
486 		(void) enter(thr_flg_reenter);
487 
488 		/*
489 		 * If this is an alternative link-map list, and this is the
490 		 * first call to initialize threads, don't let the destination
491 		 * libc be deleted.  It is possible that an auditors complete
492 		 * initialization fails, but there is presently no main link-map
493 		 * list.  As this libc has established the thread pointer, don't
494 		 * delete this libc, otherwise the initialization of libc on the
495 		 * main link-map can be compromised during its threads
496 		 * initialization.
497 		 */
498 		if (((lml->lm_flags & LML_FLG_BASELM) == 0) &&
499 		    ((rtld_flags2 & RT_FL2_PLMSETUP) == 0))
500 			MODE(lml->lm_lcs[CI_THRINIT].lc_lmp) |= RTLD_NODELETE;
501 	}
502 }
503 
504 thread_t
505 rt_thr_self()
506 {
507 	thread_t	(*fptr)(void);
508 
509 	if ((fptr = (thread_t (*)())glcs[CI_THR_SELF].lc_un.lc_func) != NULL)
510 		return ((*fptr)());
511 
512 	return (1);
513 }
514 
515 int
516 rt_mutex_lock(Rt_lock *mp)
517 {
518 	return (_lwp_mutex_lock((lwp_mutex_t *)mp));
519 }
520 
521 int
522 rt_mutex_unlock(Rt_lock *mp)
523 {
524 	return (_lwp_mutex_unlock((lwp_mutex_t *)mp));
525 }
526 
527 /*
528  * Test whether we're in a libc critical region.  Certain function references,
529  * like the "mem*" family, might require binding.  Although these functions can
530  * safely bind to auxiliary filtees, they should not be captured by auditors.
531  */
532 int
533 rt_critical()
534 {
535 	int	(*fptr)(void);
536 
537 	if ((fptr = glcs[CI_CRITICAL].lc_un.lc_func) != NULL)
538 		return ((*fptr)());
539 
540 	return (0);
541 }
542 
543 /*
544  * Mutex interfaces to resolve references from any objects extracted from
545  * libc_pic.a.  Note, as ld.so.1 is essentially single threaded these can be
546  * noops.
547  */
548 #pragma weak lmutex_lock = mutex_lock
549 /* ARGSUSED */
550 int
551 mutex_lock(mutex_t *mp)
552 {
553 	return (0);
554 }
555 
556 #pragma weak lmutex_unlock = mutex_unlock
557 /* ARGSUSED */
558 int
559 mutex_unlock(mutex_t *mp)
560 {
561 	return (0);
562 }
563 
564 /* ARGSUSED */
565 int
566 mutex_init(mutex_t *mp, int type, void *arg)
567 {
568 	return (0);
569 }
570 
571 /* ARGSUSED */
572 int
573 mutex_destroy(mutex_t *mp)
574 {
575 	return (0);
576 }
577 
578 /*
579  * This is needed to satisfy sysconf() (case _SC_THREAD_STACK_MIN)
580  */
581 size_t
582 thr_min_stack()
583 {
584 	return (sizeof (uintptr_t) * 1024);
585 }
586 
587 /*
588  * Local str[n]casecmp() interfaces for the dynamic linker,
589  * to avoid problems when linking with libc_pic.a
590  */
591 int
592 strcasecmp(const char *s1, const char *s2)
593 {
594 	extern int ascii_strcasecmp(const char *, const char *);
595 
596 	return (ascii_strcasecmp(s1, s2));
597 }
598 
599 int
600 strncasecmp(const char *s1, const char *s2, size_t n)
601 {
602 	extern int ascii_strncasecmp(const char *, const char *, size_t);
603 
604 	return (ascii_strncasecmp(s1, s2, n));
605 }
606 
607 /*
608  * The following functions are cancellation points in libc.
609  * They are called from other functions in libc that we extract
610  * and use directly.  We don't do cancellation while we are in
611  * the dynamic linker, so we redefine these to call the primitive,
612  * non-cancellation interfaces.
613  */
614 int
615 close(int fildes)
616 {
617 	extern int __close(int);
618 
619 	return (__close(fildes));
620 }
621 
622 int
623 fcntl(int fildes, int cmd, ...)
624 {
625 	extern int __fcntl(int, int, ...);
626 	intptr_t arg;
627 	va_list ap;
628 
629 	va_start(ap, cmd);
630 	arg = va_arg(ap, intptr_t);
631 	va_end(ap);
632 	return (__fcntl(fildes, cmd, arg));
633 }
634 
635 int
636 open(const char *path, int oflag, ...)
637 {
638 	extern int __open(const char *, int, mode_t);
639 	mode_t mode;
640 	va_list ap;
641 
642 	va_start(ap, oflag);
643 	mode = va_arg(ap, mode_t);
644 	va_end(ap);
645 	return (__open(path, oflag, mode));
646 }
647 
648 int
649 openat(int fd, const char *path, int oflag, ...)
650 {
651 	extern int __openat(int, const char *, int, mode_t);
652 	mode_t mode;
653 	va_list ap;
654 
655 	va_start(ap, oflag);
656 	mode = va_arg(ap, mode_t);
657 	va_end(ap);
658 	return (__openat(fd, path, oflag, mode));
659 }
660 
661 ssize_t
662 read(int fd, void *buf, size_t size)
663 {
664 	extern ssize_t __read(int, void *, size_t);
665 	return (__read(fd, buf, size));
666 }
667 
668 ssize_t
669 write(int fd, const void *buf, size_t size)
670 {
671 	extern ssize_t __write(int, const void *, size_t);
672 	return (__write(fd, buf, size));
673 }
674 
675 /*
676  * ASCII versions of ctype character classification functions.  This avoids
677  * pulling in the entire locale framework that is in libc.
678  */
679 
680 int
681 isdigit(int c)
682 {
683 	return ((c >= '0' && c <= '9') ? 1 : 0);
684 }
685 
686 int
687 isupper(int c)
688 {
689 	return ((c >= 'A' && c <= 'Z') ? 1 : 0);
690 }
691 
692 int
693 islower(int c)
694 {
695 	return ((c >= 'a' && c <= 'z') ? 1 : 0);
696 }
697 
698 int
699 isspace(int c)
700 {
701 	return (((c == ' ') || (c == '\t') || (c == '\r') || (c == '\n') ||
702 	    (c == '\v') || (c == '\f')) ? 1 : 0);
703 }
704 
705 int
706 isxdigit(int c)
707 {
708 	return ((isdigit(c) || (c >= 'A' && c <= 'F') ||
709 	    (c >= 'a' && c <= 'f')) ? 1 : 0);
710 }
711 
712 int
713 isalpha(int c)
714 {
715 	return ((isupper(c) || islower(c)) ? 1 : 0);
716 }
717 
718 int
719 isalnum(int c)
720 {
721 	return ((isalpha(c) || isdigit(c)) ? 1 : 0);
722 }
723 
724 #if defined(__i386) || defined(__amd64)
725 /*
726  * Instead of utilizing the comm page for clock_gettime, rtld uses the raw
727  * syscall instead.  Doing so decreases the surface of symbols needed from libc
728  * for a modest performance cost.
729  */
730 extern int __clock_gettime_sys(clockid_t, struct timespec *);
731 
732 int
733 __clock_gettime(clockid_t clock_id, struct timespec *tp)
734 {
735 	return (__clock_gettime_sys(clock_id, tp));
736 }
737 #endif /* defined(__i386) || defined(__amd64) */
738 
739 /*
740  * In a similar vein to the is* functions above, we also have to define our own
741  * version of strerror, as it is implemented in terms of the locale aware
742  * strerror_l, and we'd rather not have the full set of libc symbols used here.
743  */
744 extern const char _sys_errs[];
745 extern const int _sys_index[];
746 extern int _sys_num_err;
747 
748 char *
749 strerror(int errnum)
750 {
751 	if (errnum < _sys_num_err && errnum >= 0) {
752 		return (dgettext("SUNW_OST_OSLIB",
753 		    (char *)&_sys_errs[_sys_index[errnum]]));
754 	}
755 
756 	errno = EINVAL;
757 	return (dgettext("SUNW_OST_OSLIB", "Unknown error"));
758 }
759