xref: /illumos-gate/usr/src/cmd/sgs/libld/common/order.c (revision a62bb709433c06fe335121c07822de4984bdcb84)
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 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * Processing of SHF_ORDERED sections.
31  */
32 #include	<stdio.h>
33 #include	<fcntl.h>
34 #include	<link.h>
35 #include	<debug.h>
36 #include	"msg.h"
37 #include	"_libld.h"
38 
39 /*
40  * Part 1, Input processing.
41  */
42 /*
43  * Get the head section number
44  */
45 static Word
46 is_keylink_ok(Ifl_desc *ifl, Word keylink, Word limit)
47 {
48 	if ((keylink != SHN_BEFORE) && (keylink != SHN_AFTER)) {
49 		/*
50 		 * Range Check
51 		 */
52 		if ((keylink == 0) || (keylink >= limit)) {
53 			return (DBG_ORDER_LINK_OUTRANGE);
54 		}
55 
56 		/*
57 		 * The section pointed by keylink should not be an
58 		 * ordered section.
59 		 */
60 		if (ifl->ifl_isdesc[keylink]->is_shdr->sh_flags &
61 		    ALL_SHF_ORDER) {
62 			return (DBG_ORDER_INFO_ORDER);
63 		}
64 	}
65 	return (0);
66 }
67 
68 static Word
69 get_shfordered_dest(Ofl_desc *ofl, Ifl_desc *ifl, Word ndx, Word limit)
70 {
71 	Word t1_link = ndx, t2_link, ret_link;
72 	Is_desc *isp, *isp1, *isp2;
73 	int error = 0;
74 
75 	/*
76 	 * Check the sh_info of myself.
77 	 */
78 	isp = ifl->ifl_isdesc[ndx];
79 
80 	isp1 = isp;
81 	ret_link = t2_link = isp1->is_shdr->sh_link;
82 	t1_link = ndx;
83 	do {
84 		/*
85 		 * Check the validitiy of the link
86 		 */
87 		if (t2_link == 0 || t2_link >= limit) {
88 			error = DBG_ORDER_LINK_OUTRANGE;
89 			break;
90 		}
91 		isp2 = ifl->ifl_isdesc[t2_link];
92 
93 		/*
94 		 * Pointing to a bad ordered section ?
95 		 */
96 		if ((isp2->is_flags & FLG_IS_ORDERED) == 0) {
97 			error = DBG_ORDER_LINK_ERROR;
98 			break;
99 		}
100 
101 		/*
102 		 * Check sh_flag
103 		 */
104 		if (isp1->is_shdr->sh_flags != isp2->is_shdr->sh_flags) {
105 			error = DBG_ORDER_FLAGS;
106 			break;
107 		}
108 
109 		/*
110 		 * Check the validity of sh_info field.
111 		 */
112 		if ((error = is_keylink_ok(ifl,
113 		    isp->is_shdr->sh_info, limit)) != 0) {
114 			break;
115 		}
116 
117 		/*
118 		 * Can I break ?
119 		 */
120 		if (t1_link == t2_link)
121 			break;
122 
123 		/*
124 		 * Get the next link
125 		 */
126 		t1_link = t2_link;
127 		isp1 = ifl->ifl_isdesc[t1_link];
128 		ret_link = t2_link = isp1->is_shdr->sh_link;
129 
130 		/*
131 		 * Cyclic ?
132 		 */
133 		if (t2_link == ndx) {
134 			error = DBG_ORDER_CYCLIC;
135 			break;
136 		}
137 	/* CONSTANTCONDITION */
138 	} while (1);
139 
140 	if (error != 0) {
141 		ret_link = 0;
142 		DBG_CALL(Dbg_sec_order_error(ofl->ofl_lml, ifl, ndx, error));
143 	}
144 	return (ret_link);
145 }
146 
147 /*
148  * Called from process_elf().
149  * This routine does the input processing of the ordered sections.
150  */
151 uintptr_t
152 ld_process_ordered(Ifl_desc *ifl, Ofl_desc *ofl, Word ndx, Word limit)
153 {
154 	Is_desc *	isp2, * isp = ifl->ifl_isdesc[ndx];
155 	Xword		shflags = isp->is_shdr->sh_flags;
156 	uint_t		keylink;
157 	Os_desc *	osp2, * osp;
158 	Word		dest_ndx;
159 	Sort_desc *	st;
160 	Listnode *	lnp;
161 	int		error = 0;
162 
163 	/*
164 	 * I might have been checked and marked error already.
165 	 */
166 	if ((isp->is_flags & FLG_IS_ORDERED) == 0)
167 		return (0);
168 
169 	keylink = 0;
170 	if (shflags & SHF_ORDERED)
171 		keylink = isp->is_shdr->sh_info;
172 	else if (shflags & SHF_LINK_ORDER)
173 		keylink = isp->is_shdr->sh_link;
174 
175 	if ((error = is_keylink_ok(ifl, keylink, limit)) != 0) {
176 		DBG_CALL(Dbg_sec_order_error(ofl->ofl_lml, ifl, ndx, error));
177 		isp->is_flags &= ~FLG_IS_ORDERED;
178 		if (isp->is_osdesc == NULL)
179 			return ((uintptr_t)ld_place_section(ofl, isp,
180 			    isp->is_key, 0));
181 		return ((uintptr_t)isp->is_osdesc);
182 	}
183 
184 	/*
185 	 * If SHF_ORDERED is in effect - the we search for
186 	 * our desitination section based off of sh_link else
187 	 * we follow the default rules for the desitination section.
188 	 */
189 	if (shflags & SHF_ORDERED) {
190 		if ((dest_ndx = get_shfordered_dest(ofl, ifl,
191 		    ndx, limit)) == 0) {
192 			isp->is_flags &= ~FLG_IS_ORDERED;
193 			if (isp->is_osdesc == NULL)
194 				return ((uintptr_t)ld_place_section(ofl, isp,
195 				    isp->is_key, 0));
196 			return ((uintptr_t)isp->is_osdesc);
197 		}
198 	} else {
199 		/*
200 		 * SHF_LINK_ORDER coelsces into default sections - so
201 		 * we set dest_ndx to NULL to trigger this.
202 		 */
203 		dest_ndx = 0;
204 	}
205 
206 	/*
207 	 * Place the section into it's output section.
208 	 */
209 	if ((osp = isp->is_osdesc) == NULL) {
210 		if ((osp = ld_place_section(ofl, isp, isp->is_ident,
211 		    dest_ndx)) == (Os_desc *)S_ERROR)
212 			return ((uintptr_t)S_ERROR);
213 		if (!osp)
214 			return (0);
215 	}
216 
217 	/*
218 	 * If the output section is not yet on the ordered
219 	 * list - place it on the list.
220 	 */
221 	osp2 = NULL;
222 	for (LIST_TRAVERSE(&ofl->ofl_ordered, lnp, osp2))
223 		if (osp2 == osp)
224 			break;
225 
226 	if (osp != osp2)
227 		if (list_appendc(&(ofl->ofl_ordered), osp) == 0)
228 			return ((uintptr_t)S_ERROR);
229 
230 	/*
231 	 * Output section has been found - set up it's
232 	 * sorting information.
233 	 */
234 	if (osp->os_sort == 0) {
235 		if ((osp->os_sort = libld_calloc(1, sizeof (Sort_desc))) == 0)
236 			return (S_ERROR);
237 	}
238 	st = osp->os_sort;
239 
240 	if (keylink == SHN_BEFORE) {
241 		st->st_beforecnt++;
242 	} else if (keylink == SHN_AFTER) {
243 		st->st_aftercnt++;
244 	} else {
245 		st->st_ordercnt++;
246 		isp2 = ifl->ifl_isdesc[keylink];
247 		if (isp2->is_flags & FLG_IS_DISCARD) {
248 			eprintf(ofl->ofl_lml, ERR_FATAL,
249 			    MSG_INTL(MSG_FIL_BADORDREF), ifl->ifl_name,
250 			    isp->is_name, isp->is_scnndx, isp2->is_name,
251 			    isp2->is_scnndx);
252 			return (S_ERROR);
253 		}
254 		osp2 = isp2->is_osdesc;
255 		osp2->os_flags |= FLG_OS_ORDER_KEY;
256 		osp2->os_sgdesc->sg_flags |= FLG_SG_KEY;
257 		isp2->is_flags |= FLG_IS_KEY;
258 	}
259 
260 	return ((uintptr_t)osp);
261 }
262 
263 /*
264  * Part 2, Sorting processing
265  */
266 
267 /*
268  * Traverse all segments looking for section ordering information that hasn't
269  * been used.  If found give a warning message to the user.  Also, check if
270  * there are any SHF_ORDERED key sections, and if so set up sort key values.
271  */
272 void
273 ld_sec_validate(Ofl_desc * ofl)
274 {
275 	Listnode *	lnp1;
276 	Sg_desc *	sgp;
277 	int 		key = 1;
278 
279 	for (LIST_TRAVERSE(&ofl->ofl_segs, lnp1, sgp)) {
280 		Listnode *	lnp2;
281 		Sec_order *	scop;
282 		Os_desc *	osp;
283 
284 		for (LIST_TRAVERSE(&sgp->sg_secorder, lnp2, scop))
285 			if (!(scop->sco_flags & FLG_SGO_USED))
286 				eprintf(ofl->ofl_lml, ERR_WARNING,
287 				    MSG_INTL(MSG_MAP_SECORDER),
288 				    sgp->sg_name, scop->sco_secname);
289 
290 		if ((sgp->sg_flags & FLG_SG_KEY) == 0)
291 			continue;
292 
293 		for (LIST_TRAVERSE(&(sgp->sg_osdescs), lnp2, osp)) {
294 			Listnode *	lnp3;
295 			Is_desc *	isp;
296 
297 			if ((osp->os_flags & FLG_OS_ORDER_KEY) == 0)
298 				continue;
299 
300 			for (LIST_TRAVERSE(&(osp->os_isdescs), lnp3, isp)) {
301 				if (isp->is_flags & FLG_IS_KEY) {
302 					isp->is_key = key++;
303 				}
304 			}
305 		}
306 	}
307 }
308 
309 static int
310 setup_sortbuf(Os_desc *osp)
311 {
312 	Sort_desc	*st = osp->os_sort;
313 	Word		num_after = 0, num_before = 0, num_order = 0;
314 	Listnode	*lnp1;
315 	Is_desc		*isp;
316 
317 	if ((st == NULL) ||
318 	    ((st->st_ordercnt + st->st_beforecnt + st->st_aftercnt) == 0))
319 		return (0);
320 
321 	/*
322 	 * Get memory
323 	 */
324 	if (st->st_beforecnt != 0) {
325 		if ((st->st_before =
326 		    libld_calloc(st->st_beforecnt, sizeof (Is_desc *))) == 0)
327 			return (0);
328 	}
329 	if (st->st_ordercnt != 0) {
330 		if ((st->st_order =
331 		    libld_calloc(st->st_ordercnt, sizeof (Is_desc *))) == 0)
332 			return (0);
333 	}
334 	if (st->st_aftercnt != 0) {
335 		if ((st->st_after =
336 		    libld_calloc(st->st_aftercnt, sizeof (Is_desc *))) == 0)
337 			return (0);
338 	}
339 
340 	/*
341 	 * Set info.
342 	 */
343 	for (LIST_TRAVERSE(&(osp->os_isdescs), lnp1, isp)) {
344 		Word	keylink = 0;
345 
346 		if ((isp->is_flags & FLG_IS_ORDERED) == 0)
347 			continue;
348 
349 		if (isp->is_shdr->sh_flags & SHF_ORDERED)
350 			keylink = isp->is_shdr->sh_info;
351 		else if (isp->is_shdr->sh_flags & SHF_LINK_ORDER)
352 			keylink = isp->is_shdr->sh_link;
353 
354 		if (keylink == SHN_BEFORE)
355 			st->st_before[num_before++] = isp;
356 		else if (keylink == SHN_AFTER)
357 			st->st_after[num_after++] = isp;
358 		else
359 			st->st_order[num_order++] = isp;
360 	}
361 	return (1);
362 }
363 
364 static int
365 comp(const void *ss1, const void *ss2)
366 {
367 	Is_desc		*s1 = *((Is_desc **)ss1);
368 	Is_desc		*s2 = *((Is_desc **)ss2);
369 	Is_desc		*i1, *i2;
370 	Word		ndx1, ndx2;
371 
372 	if (s1->is_shdr->sh_flags & SHF_ORDERED)  {
373 		ndx1 = s1->is_shdr->sh_info;
374 	} else {
375 		ndx1 = s1->is_shdr->sh_link;
376 	}
377 
378 	if (s2->is_shdr->sh_flags & SHF_ORDERED)  {
379 		ndx2 = s2->is_shdr->sh_info;
380 	} else {
381 		ndx2 = s2->is_shdr->sh_link;
382 	}
383 
384 	i1 = s1->is_file->ifl_isdesc[ndx1];
385 	i2 = s2->is_file->ifl_isdesc[ndx2];
386 
387 	if (i1->is_key > i2->is_key)
388 		return (1);
389 	if (i1->is_key < i2->is_key)
390 		return (-1);
391 	return (0);
392 }
393 
394 uintptr_t
395 ld_sort_ordered(Ofl_desc *ofl)
396 {
397 	Listnode *lnp1;
398 	Os_desc *osp;
399 
400 	DBG_CALL(Dbg_sec_order_list(ofl, 0));
401 
402 	/*
403 	 * Sort Sections
404 	 */
405 	for (LIST_TRAVERSE(&ofl->ofl_ordered, lnp1, osp)) {
406 		int		i;
407 		List		islist;
408 		Listnode *	lnp2;
409 		Is_desc *	isp;
410 		Sort_desc *	st = osp->os_sort;
411 
412 		if (setup_sortbuf(osp) == 0)
413 			return (S_ERROR);
414 
415 		islist = osp->os_isdescs;
416 		osp->os_isdescs.head = 0;
417 		osp->os_isdescs.tail = 0;
418 
419 		/*
420 		 * Sorting.
421 		 * First Sort the ordered sections.
422 		 */
423 		if (st->st_ordercnt != 0)
424 			qsort((char *)st->st_order, st->st_ordercnt,
425 				sizeof (Is_desc *), comp);
426 
427 		/*
428 		 * Place SHN_BEFORE at head of list
429 		 */
430 		for (i = 0; i < st->st_beforecnt; i++) {
431 			if (list_appendc(&(osp->os_isdescs),
432 			    st->st_before[i]) == 0)
433 				return (S_ERROR);
434 		}
435 
436 		/*
437 		 * Next come 'linked' ordered sections
438 		 */
439 		for (i = 0; i < st->st_ordercnt; i++) {
440 			if (list_appendc(&(osp->os_isdescs),
441 			    st->st_order[i]) == 0)
442 				return (S_ERROR);
443 		}
444 
445 		/*
446 		 * Now we list any sections which have no sorting
447 		 * specifications - in the order they were input.
448 		 */
449 		for (LIST_TRAVERSE(&islist, lnp2, isp)) {
450 			if (isp->is_flags & FLG_IS_ORDERED)
451 				continue;
452 			if (list_appendc(&(osp->os_isdescs),
453 			    isp) == 0)
454 				return (S_ERROR);
455 		}
456 
457 		/*
458 		 * And the end of the list are the SHN_AFTER sections.
459 		 */
460 		for (i = 0; i < st->st_aftercnt; i++) {
461 			if (list_appendc(&(osp->os_isdescs),
462 			    st->st_after[i]) == 0)
463 				return (S_ERROR);
464 		}
465 	}
466 	DBG_CALL(Dbg_sec_order_list(ofl, 1));
467 	return (0);
468 }
469