xref: /illumos-gate/usr/src/cmd/sgs/rtld/common/external.c (revision 0250c53ad267726f2438e3c6556199a0bbf588a2)
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 (c) 2017, 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 <fcntl.h>
188 #include "_elf.h"
189 #include "_rtld.h"
190 
191 /*
192  * This interface provides the unified process model communication between
193  * ld.so.1 and libc.  This interface can be called a number of times:
194  *
195  *   -	Initially, this interface is called to process RTLDINFO.  This data
196  *	structure is typically provided by libc, and contains the address of
197  *	libc interfaces that must be called to initialize threads information.
198  *
199  *   -	_ld_libc(), this interface can also be called by libc at process
200  *	initialization, after libc has been loaded and relocated, but before
201  *	control has been passed to any user code (.init's or main()).  This
202  *	call provides additional libc interface information that ld.so.1 must
203  *	call during process execution.
204  *
205  *   -	_ld_libc() can also be called by libc during process execution to
206  *	re-establish interfaces such as the locale.
207  */
208 static void
get_lcinterface(Rt_map * lmp,Lc_interface * funcs)209 get_lcinterface(Rt_map *lmp, Lc_interface *funcs)
210 {
211 	int		threaded = 0, entry = 0, tag;
212 	Lm_list		*lml;
213 	Lc_desc		*lcp;
214 
215 	if ((lmp == NULL) || (funcs == NULL))
216 		return;
217 
218 	/*
219 	 * Once the process is active, ensure we grab a lock.
220 	 */
221 	if (rtld_flags & RT_FL_APPLIC)
222 		entry = enter(0);
223 
224 	lml = LIST(lmp);
225 	lcp = &lml->lm_lcs[0];
226 
227 	DBG_CALL(Dbg_util_nl(lml, DBG_NL_STD));
228 
229 	for (tag = funcs->ci_tag; tag; tag = (++funcs)->ci_tag) {
230 		char	*gptr;
231 		char	*lptr = funcs->ci_un.ci_ptr;
232 
233 		DBG_CALL(Dbg_util_lcinterface(lmp, tag, lptr));
234 
235 		if (tag >= CI_MAX)
236 			continue;
237 
238 		/*
239 		 * Maintain all interfaces on a per-link-map basis.  Note, for
240 		 * most interfaces, only the first interface is used for any
241 		 * link-map list.  This prevents accidents with developers who
242 		 * manage to load two different versions of libc.
243 		 */
244 		if ((lcp[tag].lc_lmp) &&
245 		    (tag != CI_LCMESSAGES) && (tag != CI_VERSION)) {
246 			DBG_CALL(Dbg_unused_lcinterface(lmp,
247 			    lcp[tag].lc_lmp, tag));
248 			continue;
249 		}
250 
251 		lcp[tag].lc_un.lc_ptr = lptr;
252 		lcp[tag].lc_lmp = lmp;
253 
254 		gptr = glcs[tag].lc_un.lc_ptr;
255 
256 		/*
257 		 * Process any interfaces that must be maintained on a global
258 		 * basis.
259 		 */
260 		switch (tag) {
261 		case CI_ATEXIT:
262 			break;
263 
264 		case CI_LCMESSAGES:
265 			/*
266 			 * At startup, ld.so.1 can establish a locale from one
267 			 * of the locale family of environment variables (see
268 			 * ld_str_env() and readenv_user()).  During process
269 			 * execution the locale can also be changed by the user.
270 			 * This interface is called from libc should the locale
271 			 * be modified.  Presently, only one global locale is
272 			 * maintained for all link-map lists, and only objects
273 			 * on the primrary link-map may change this locale.
274 			 */
275 			if ((lml->lm_flags & LML_FLG_BASELM) &&
276 			    ((gptr == NULL) || (strcmp(gptr, lptr) != 0))) {
277 				/*
278 				 * If we've obtained a message locale (typically
279 				 * supplied via libc's setlocale()), then
280 				 * register the locale for use in dgettext() so
281 				 * as to reestablish the locale for ld.so.1's
282 				 * messages.
283 				 */
284 				if (gptr) {
285 					free((void *)gptr);
286 					rtld_flags |= RT_FL_NEWLOCALE;
287 				}
288 				glcs[tag].lc_un.lc_ptr = strdup(lptr);
289 
290 				/*
291 				 * Clear any cached messages.
292 				 */
293 				bzero(err_strs, sizeof (err_strs));
294 				nosym_str = NULL;
295 			}
296 			break;
297 
298 		case CI_BIND_GUARD:
299 		case CI_BIND_CLEAR:
300 		case CI_THR_SELF:
301 		case CI_CRITICAL:
302 			/*
303 			 * If the global vector is unset, or this is the primary
304 			 * link-map, set the global vector.
305 			 */
306 			if ((gptr == NULL) || (lml->lm_flags & LML_FLG_BASELM))
307 				glcs[tag].lc_un.lc_ptr = lptr;
308 
309 			/* FALLTHROUGH */
310 
311 		case CI_TLS_MODADD:
312 		case CI_TLS_MODREM:
313 		case CI_TLS_STATMOD:
314 		case CI_THRINIT:
315 			threaded++;
316 			break;
317 
318 		case CI_VERSION:
319 			if ((rtld_flags2 & RT_FL2_RTLDSEEN) == 0) {
320 				Aliste	idx;
321 				Lm_list	*lml2;
322 				int	version;
323 
324 				rtld_flags2 |= RT_FL2_RTLDSEEN;
325 
326 				version = funcs->ci_un.ci_val;
327 #if defined(CI_V_FIVE)
328 				if (version >= CI_V_FIVE) {
329 					thr_flg_nolock = THR_FLG_NOLOCK;
330 					thr_flg_reenter = THR_FLG_REENTER;
331 				}
332 #endif
333 				if (version < CI_V_FOUR)
334 					break;
335 
336 				rtld_flags2 |= RT_FL2_UNIFPROC;
337 
338 				/*
339 				 * We might have seen an auditor which is not
340 				 * dependent on libc.  Such an auditor's link
341 				 * map list has LML_FLG_HOLDLOCK set.  This
342 				 * lock needs to be dropped.  Refer to
343 				 * audit_setup() in audit.c.
344 				 */
345 				if ((rtld_flags2 & RT_FL2_HASAUDIT) == 0)
346 					break;
347 
348 				/*
349 				 * Yes, we did.  Take care of them.
350 				 */
351 				for (APLIST_TRAVERSE(dynlm_list, idx, lml2)) {
352 					Rt_map *map = (Rt_map *)lml2->lm_head;
353 
354 					if (FLAGS(map) & FLG_RT_AUDIT) {
355 						lml2->lm_flags &=
356 						    ~LML_FLG_HOLDLOCK;
357 					}
358 				}
359 			}
360 			break;
361 
362 		default:
363 			break;
364 		}
365 	}
366 
367 	if (threaded) {
368 		/*
369 		 * If a version of libc gives us only a subset of the TLS
370 		 * interfaces, it's confused and we discard the whole lot.
371 		 */
372 		if (((lcp[CI_TLS_MODADD].lc_un.lc_func != NULL) &&
373 		    (lcp[CI_TLS_MODREM].lc_un.lc_func != NULL) &&
374 		    (lcp[CI_TLS_STATMOD].lc_un.lc_func != NULL)) == 0) {
375 			lcp[CI_TLS_MODADD].lc_un.lc_func = NULL;
376 			lcp[CI_TLS_MODREM].lc_un.lc_func = NULL;
377 			lcp[CI_TLS_STATMOD].lc_un.lc_func = NULL;
378 		}
379 
380 		/*
381 		 * Indicate that we're now thread capable.
382 		 */
383 		if ((lml->lm_flags & LML_FLG_RTLDLM) == 0)
384 			rtld_flags |= RT_FL_THREADS;
385 	}
386 
387 	if (entry)
388 		leave(lml, 0);
389 }
390 
391 /*
392  * At this point we know we have a set of objects that have been fully analyzed
393  * and relocated.  Prior to the next major step of running .init sections (ie.
394  * running user code), retrieve any RTLDINFO interfaces.
395  */
396 int
rt_get_extern(Lm_list * lml,Rt_map * lmp)397 rt_get_extern(Lm_list *lml, Rt_map *lmp)
398 {
399 	if (lml->lm_rti) {
400 		Aliste		idx;
401 		Rti_desc	*rti;
402 
403 		for (ALIST_TRAVERSE(lml->lm_rti, idx, rti))
404 			get_lcinterface(rti->rti_lmp, rti->rti_info);
405 
406 		free(lml->lm_rti);
407 		lml->lm_rti = 0;
408 	}
409 
410 	/*
411 	 * Perform some sanity checks.  If we have TLS requirements we better
412 	 * have the associated external interfaces.
413 	 */
414 	if (lml->lm_tls &&
415 	    (lml->lm_lcs[CI_TLS_STATMOD].lc_un.lc_func == NULL)) {
416 		eprintf(lml, ERR_FATAL, MSG_INTL(MSG_TLS_NOSUPPORT),
417 		    NAME(lmp));
418 		return (0);
419 	}
420 	return (1);
421 }
422 
423 /*
424  * Provide an interface for libc to communicate additional interface
425  * information.
426  */
427 void
_ld_libc(void * ptr)428 _ld_libc(void *ptr)
429 {
430 	get_lcinterface(_caller(caller(), CL_EXECDEF), (Lc_interface *)ptr);
431 }
432 
433 static int	bindmask = 0;
434 
435 int
rt_bind_guard(int flags)436 rt_bind_guard(int flags)
437 {
438 	int	(*fptr)(int);
439 	int	bindflag;
440 
441 	if ((fptr = glcs[CI_BIND_GUARD].lc_un.lc_func) != NULL) {
442 		return ((*fptr)(flags));
443 	} else {
444 		bindflag = (flags & THR_FLG_RTLD);
445 		if ((bindflag & bindmask) == 0) {
446 			bindmask |= bindflag;
447 			return (1);
448 		}
449 		return (0);
450 	}
451 }
452 
453 int
rt_bind_clear(int flags)454 rt_bind_clear(int flags)
455 {
456 	int	(*fptr)(int);
457 	int	bindflag;
458 
459 	if ((fptr = glcs[CI_BIND_CLEAR].lc_un.lc_func) != NULL) {
460 		return ((*fptr)(flags));
461 	} else {
462 		bindflag = (flags & THR_FLG_RTLD);
463 		if (bindflag == 0)
464 			return (bindmask);
465 		else {
466 			bindmask &= ~bindflag;
467 			return (0);
468 		}
469 	}
470 }
471 
472 /*
473  * Make sure threads have been initialized.  This interface is called once for
474  * each link-map list.
475  */
476 void
rt_thr_init(Lm_list * lml)477 rt_thr_init(Lm_list *lml)
478 {
479 	int	(*fptr)(void);
480 
481 	if ((fptr = 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 		(void) (*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
rt_thr_self()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
rt_mutex_lock(Rt_lock * mp)516 rt_mutex_lock(Rt_lock *mp)
517 {
518 	return (_lwp_mutex_lock((lwp_mutex_t *)mp));
519 }
520 
521 int
rt_mutex_unlock(Rt_lock * mp)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
rt_critical()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
mutex_lock(mutex_t * mp)551 mutex_lock(mutex_t *mp)
552 {
553 	return (0);
554 }
555 
556 #pragma weak lmutex_unlock = mutex_unlock
557 /* ARGSUSED */
558 int
mutex_unlock(mutex_t * mp)559 mutex_unlock(mutex_t *mp)
560 {
561 	return (0);
562 }
563 
564 /* ARGSUSED */
565 int
mutex_init(mutex_t * mp,int type,void * arg)566 mutex_init(mutex_t *mp, int type, void *arg)
567 {
568 	return (0);
569 }
570 
571 /* ARGSUSED */
572 int
mutex_destroy(mutex_t * mp)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
thr_min_stack()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
strcasecmp(const char * s1,const char * s2)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
strncasecmp(const char * s1,const char * s2,size_t n)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
close(int fildes)615 close(int fildes)
616 {
617 	extern int __close(int);
618 
619 	return (__close(fildes));
620 }
621 
622 int
fcntl(int fildes,int cmd,...)623 fcntl(int fildes, int cmd, ...)
624 {
625 	extern int __fcntl(int, int, ...);
626 	intptr_t arg, arg1 = 0;
627 	va_list ap;
628 
629 	va_start(ap, cmd);
630 	switch (cmd) {
631 	case F_DUP3FD:
632 		arg = va_arg(ap, int);
633 		arg1 = va_arg(ap, int);
634 		break;
635 	default:
636 		arg = va_arg(ap, intptr_t);
637 		break;
638 	}
639 	va_end(ap);
640 	return (__fcntl(fildes, cmd, arg, arg1));
641 }
642 
643 int
open(const char * path,int oflag,...)644 open(const char *path, int oflag, ...)
645 {
646 	extern int __open(const char *, int, mode_t);
647 	mode_t mode;
648 	va_list ap;
649 
650 	va_start(ap, oflag);
651 	mode = va_arg(ap, mode_t);
652 	va_end(ap);
653 	return (__open(path, oflag, mode));
654 }
655 
656 int
openat(int fd,const char * path,int oflag,...)657 openat(int fd, const char *path, int oflag, ...)
658 {
659 	extern int __openat(int, const char *, int, mode_t);
660 	mode_t mode;
661 	va_list ap;
662 
663 	va_start(ap, oflag);
664 	mode = va_arg(ap, mode_t);
665 	va_end(ap);
666 	return (__openat(fd, path, oflag, mode));
667 }
668 
669 ssize_t
read(int fd,void * buf,size_t size)670 read(int fd, void *buf, size_t size)
671 {
672 	extern ssize_t __read(int, void *, size_t);
673 	return (__read(fd, buf, size));
674 }
675 
676 ssize_t
write(int fd,const void * buf,size_t size)677 write(int fd, const void *buf, size_t size)
678 {
679 	extern ssize_t __write(int, const void *, size_t);
680 	return (__write(fd, buf, size));
681 }
682 
683 /*
684  * ASCII versions of ctype character classification functions.  This avoids
685  * pulling in the entire locale framework that is in libc.
686  */
687 
688 int
isdigit(int c)689 isdigit(int c)
690 {
691 	return ((c >= '0' && c <= '9') ? 1 : 0);
692 }
693 
694 int
isupper(int c)695 isupper(int c)
696 {
697 	return ((c >= 'A' && c <= 'Z') ? 1 : 0);
698 }
699 
700 int
islower(int c)701 islower(int c)
702 {
703 	return ((c >= 'a' && c <= 'z') ? 1 : 0);
704 }
705 
706 int
isspace(int c)707 isspace(int c)
708 {
709 	return (((c == ' ') || (c == '\t') || (c == '\r') || (c == '\n') ||
710 	    (c == '\v') || (c == '\f')) ? 1 : 0);
711 }
712 
713 int
isxdigit(int c)714 isxdigit(int c)
715 {
716 	return ((isdigit(c) || (c >= 'A' && c <= 'F') ||
717 	    (c >= 'a' && c <= 'f')) ? 1 : 0);
718 }
719 
720 int
isalpha(int c)721 isalpha(int c)
722 {
723 	return ((isupper(c) || islower(c)) ? 1 : 0);
724 }
725 
726 int
isalnum(int c)727 isalnum(int c)
728 {
729 	return ((isalpha(c) || isdigit(c)) ? 1 : 0);
730 }
731 
732 #if defined(__i386) || defined(__amd64)
733 /*
734  * Instead of utilizing the comm page for clock_gettime and gettimeofday, rtld
735  * uses the raw syscall instead.  Doing so decreases the surface of symbols
736  * needed from libc for a modest performance cost.
737  */
738 extern int __clock_gettime_sys(clockid_t, struct timespec *);
739 
740 int
__clock_gettime(clockid_t clock_id,struct timespec * tp)741 __clock_gettime(clockid_t clock_id, struct timespec *tp)
742 {
743 	return (__clock_gettime_sys(clock_id, tp));
744 }
745 
746 int
gettimeofday(struct timeval * tv,void * tz)747 gettimeofday(struct timeval *tv, void *tz)
748 {
749 	if (tv != NULL) {
750 		/*
751 		 * Perform the same logic as the libc gettimeofday() when it
752 		 * lacks comm page support: Make the clock_gettime syscall and
753 		 * divide out the tv_usec field as required.
754 		 */
755 		(void) __clock_gettime_sys(CLOCK_REALTIME, (timespec_t *)tv);
756 		tv->tv_usec /= 1000;
757 	}
758 
759 	return (0);
760 }
761 #endif /* defined(__i386) || defined(__amd64) */
762 
763 /*
764  * In a similar vein to the is* functions above, we also have to define our own
765  * version of strerror, as it is implemented in terms of the locale aware
766  * strerror_l, and we'd rather not have the full set of libc symbols used here.
767  */
768 extern const char _sys_errs[];
769 extern const int _sys_index[];
770 extern int _sys_num_err;
771 
772 char *
strerror(int errnum)773 strerror(int errnum)
774 {
775 	if (errnum < _sys_num_err && errnum >= 0) {
776 		return (dgettext("SUNW_OST_OSLIB",
777 		    (char *)&_sys_errs[_sys_index[errnum]]));
778 	}
779 
780 	errno = EINVAL;
781 	return (dgettext("SUNW_OST_OSLIB", "Unknown error"));
782 }
783