xref: /illumos-gate/usr/src/cmd/sgs/libld/common/outfile.c (revision 0f5dca202932d0332edc1fe814b977277a94fe5c)
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) 1988 AT&T
24  *	  All Rights Reserved
25  *
26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
27  * Use is subject to license terms.
28  */
29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
30 
31 /*
32  * This file contains the functions responsible for opening the output file
33  * image, associating the appropriate input elf structures with the new image,
34  * and obtaining new elf structures to define the new image.
35  */
36 #include	<stdio.h>
37 #include	<sys/stat.h>
38 #include	<fcntl.h>
39 #include	<link.h>
40 #include	<errno.h>
41 #include	<string.h>
42 #include	<limits.h>
43 #include	<debug.h>
44 #include	<unistd.h>
45 #include	"msg.h"
46 #include	"_libld.h"
47 
48 /*
49  * Determine a least common multiplier.  Input sections contain an alignment
50  * requirement, which elf_update() uses to insure that the section is aligned
51  * correctly off of the base of the elf image.  We must also insure that the
52  * sections mapping is congruent with this alignment requirement.  For each
53  * input section associated with a loadable segment determine whether the
54  * segments alignment must be adjusted to compensate for a sections alignment
55  * requirements.
56  */
57 Xword
58 ld_lcm(Xword a, Xword b)
59 {
60 	Xword	_r, _a, _b;
61 
62 	if ((_a = a) == 0)
63 		return (b);
64 	if ((_b = b) == 0)
65 		return (a);
66 
67 	if (_a > _b)
68 		_a = b, _b = a;
69 	while ((_r = _b % _a) != 0)
70 		_b = _a, _a = _r;
71 	return ((a / _a) * b);
72 }
73 
74 /*
75  * Open the output file and insure the correct access modes.
76  */
77 uintptr_t
78 ld_open_outfile(Ofl_desc * ofl)
79 {
80 	mode_t		mode;
81 	struct stat	status;
82 
83 	/*
84 	 * Determine the required file mode from the type of output file we
85 	 * are creating.
86 	 */
87 	mode = (ofl->ofl_flags & (FLG_OF_EXEC | FLG_OF_SHAROBJ))
88 		? 0777 : 0666;
89 
90 	/* Determine if the output file already exists */
91 	if (stat(ofl->ofl_name, &status) == 0) {
92 		if ((status.st_mode & S_IFMT) != S_IFREG) {
93 			/*
94 			 * It is not a regular file, so don't delete it
95 			 * or allow it to be deleted.  This allows root
96 			 * users to specify /dev/null output file for
97 			 * verification links.
98 			 */
99 			ofl->ofl_flags1 |= FLG_OF1_NONREG;
100 		} else {
101 			/*
102 			 * It's a regular file, so unlink it. In standard
103 			 * Unix fashion, the old file will continue to
104 			 * exist until its link count drops to 0 and no
105 			 * process has the file open. In the meantime, we
106 			 * create a new file (inode) under the same name,
107 			 * available for new use.
108 			 *
109 			 * The advantage of this policy is that creating
110 			 * a new executable or sharable library does not
111 			 * corrupt existing processes using the old file.
112 			 * A possible disadvantage is that if the existing
113 			 * file has a (link_count > 1), the other names will
114 			 * continue to reference the old inode, thus
115 			 * breaking the link.
116 			 *
117 			 * A subtlety here is that POSIX says we are not
118 			 * supposed to replace a non-writable file, which
119 			 * is something that unlink() is happy to do. The
120 			 * only 100% reliable test against this is to open
121 			 * the file for non-destructive write access. If the
122 			 * open succeeds, we are clear to unlink it, and if
123 			 * not, then the error generated is the error we
124 			 * need to report.
125 			 */
126 			if ((ofl->ofl_fd = open(ofl->ofl_name, O_RDWR,
127 			    mode)) < 0) {
128 				int	err = errno;
129 
130 				if (err != ENOENT) {
131 					eprintf(ofl->ofl_lml, ERR_FATAL,
132 					    MSG_INTL(MSG_SYS_OPEN),
133 					    ofl->ofl_name, strerror(err));
134 					return (S_ERROR);
135 				}
136 			} else {
137 				(void) close(ofl->ofl_fd);
138 			}
139 
140 			if ((unlink(ofl->ofl_name) == -1) &&
141 			    (errno != ENOENT)) {
142 				int err = errno;
143 
144 				eprintf(ofl->ofl_lml, ERR_FATAL,
145 					MSG_INTL(MSG_SYS_UNLINK),
146 					ofl->ofl_name, strerror(err));
147 				return (S_ERROR);
148 			}
149 		}
150 	}
151 
152 	/*
153 	 * Open (or create) the output file name (ofl_fd acts as a global
154 	 * flag to ldexit() signifying whether the output file should be
155 	 * removed or not on error).
156 	 */
157 	if ((ofl->ofl_fd = open(ofl->ofl_name, O_RDWR | O_CREAT | O_TRUNC,
158 	    mode)) < 0) {
159 		int	err = errno;
160 
161 		eprintf(ofl->ofl_lml, ERR_FATAL, MSG_INTL(MSG_SYS_OPEN),
162 		    ofl->ofl_name, strerror(err));
163 		return (S_ERROR);
164 	}
165 
166 	return (1);
167 }
168 
169 
170 /*
171  * If we are creating a memory model we need to update the present memory image.
172  * First we need to call elf_update(ELF_C_NULL) which will calculate the offsets
173  * of each section and its associated data buffers.  From this information we
174  * can then determine what padding is required.
175  * Two actions are necessary to convert the present disc image into a memory
176  * image:
177  *
178  *  o	Loadable segments must be padded so that the next segments virtual
179  *	address and file offset are the same.
180  *
181  *  o	NOBITS sections must be converted into allocated, null filled sections.
182  */
183 static uintptr_t
184 pad_outfile(Ofl_desc *ofl)
185 {
186 	Listnode	*lnp;
187 	off_t		offset;
188 	Elf_Scn		*oscn = 0;
189 	Sg_desc		*sgp;
190 	Ehdr		*ehdr;
191 
192 	/*
193 	 * Update all the elf structures.  This will assign offsets to the
194 	 * section headers and data buffers as they relate to the new image.
195 	 */
196 	if (elf_update(ofl->ofl_welf, ELF_C_NULL) == -1) {
197 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_UPDATE),
198 		    ofl->ofl_name);
199 		return (S_ERROR);
200 	}
201 	if ((ehdr = elf_getehdr(ofl->ofl_welf)) == NULL) {
202 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_GETEHDR),
203 		    ofl->ofl_name);
204 		return (S_ERROR);
205 	}
206 
207 	/*
208 	 * Initialize the offset by skipping the Elf header and program
209 	 * headers.
210 	 */
211 	offset = ehdr->e_phoff + (ehdr->e_phnum * ehdr->e_phentsize);
212 
213 	/*
214 	 * Traverse the segment list looking for loadable segments.
215 	 */
216 	for (LIST_TRAVERSE(&ofl->ofl_segs, lnp, sgp)) {
217 		Phdr	*phdr = &(sgp->sg_phdr);
218 		Os_desc	**ospp, *osp;
219 		Aliste	off;
220 
221 		/*
222 		 * If we've already processed a loadable segment, the `scn'
223 		 * variable will be initialized to the last section that was
224 		 * part of that segment.  Add sufficient padding to this section
225 		 * to cause the next segments virtual address and file offset to
226 		 * be the same.
227 		 */
228 		if (oscn && (phdr->p_type == PT_LOAD)) {
229 			Elf_Data *	data;
230 			size_t 		size;
231 
232 			size = (size_t)(S_ROUND(offset, phdr->p_align) -
233 			    offset);
234 
235 			if ((data = elf_newdata(oscn)) == NULL) {
236 				eprintf(ofl->ofl_lml, ERR_ELF,
237 				    MSG_INTL(MSG_ELF_NEWDATA), ofl->ofl_name);
238 				return (S_ERROR);
239 			}
240 			if ((data->d_buf = libld_calloc(size, 1)) == 0)
241 				return (S_ERROR);
242 
243 			data->d_type = ELF_T_BYTE;
244 			data->d_size = size;
245 			data->d_align = 1;
246 			data->d_version = ofl->ofl_dehdr->e_version;
247 		}
248 
249 		/*
250 		 * Traverse the output sections for this segment calculating the
251 		 * offset of each section. Retain the final section descriptor
252 		 * as this will be where any padding buffer will be added.
253 		 */
254 		for (ALIST_TRAVERSE(sgp->sg_osdescs, off, ospp)) {
255 			Shdr	*shdr;
256 
257 			osp = *ospp;
258 			shdr = osp->os_shdr;
259 
260 			offset = (off_t)S_ROUND(offset, shdr->sh_addralign);
261 			offset += shdr->sh_size;
262 
263 			/*
264 			 * If this is a NOBITS output section convert all of
265 			 * its associated input sections into real, null filled,
266 			 * data buffers, and change the section to PROGBITS.
267 			 */
268 			if (shdr->sh_type == SHT_NOBITS)
269 				shdr->sh_type = SHT_PROGBITS;
270 		}
271 
272 		/*
273 		 * If this is a loadable segment retain the last output section
274 		 * descriptor.  This acts both as a flag that a loadable
275 		 * segment has been seen, and as the segment to which a padding
276 		 * buffer will be added.
277 		 */
278 		if (phdr->p_type == PT_LOAD)
279 			oscn = osp->os_scn;
280 	}
281 	return (1);
282 }
283 
284 /*
285  * Create an output section.  The first instance of an input section triggers
286  * the creation of a new output section.
287  */
288 static uintptr_t
289 create_outsec(Ofl_desc *ofl, Sg_desc *sgp, Os_desc *osp, Word ptype, int shidx,
290     Boolean fixalign)
291 {
292 	Elf_Scn	*scn;
293 	Shdr	*shdr;
294 
295 	/*
296 	 * Get a section descriptor for the section.
297 	 */
298 	if ((scn = elf_newscn(ofl->ofl_welf)) == NULL) {
299 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_NEWSCN),
300 		    ofl->ofl_name);
301 		return (S_ERROR);
302 	}
303 	osp->os_scn = scn;
304 
305 	/*
306 	 * Get a new section header table entry and copy the pertinent
307 	 * information from the in-core descriptor.
308 	 */
309 	if ((shdr = elf_getshdr(scn)) == NULL) {
310 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_GETSHDR),
311 		    ofl->ofl_name);
312 		return (S_ERROR);
313 	}
314 	*shdr = *(osp->os_shdr);
315 	osp->os_shdr = shdr;
316 
317 	/*
318 	 * If this is the first section within a loadable segment, and the
319 	 * alignment needs to be updated, record this section.
320 	 */
321 	if ((fixalign == TRUE) && (ptype == PT_LOAD) && (shidx == 1))
322 		sgp->sg_fscn = scn;
323 
324 	/*
325 	 * Remove any SHF_ORDERED or SHF_LINK_ORDER flags.  If we are not
326 	 * building a relocatable object, remove any SHF_GROUP flag.
327 	 */
328 	osp->os_shdr->sh_flags &= ~ALL_SHF_ORDER;
329 	if ((ofl->ofl_flags & FLG_OF_RELOBJ) == 0)
330 		osp->os_shdr->sh_flags &= ~SHF_GROUP;
331 
332 	/*
333 	 * If this is a TLS section, save it so that the PT_TLS program header
334 	 * information can be established after the output image has been
335 	 * initially created.  At this point, all TLS input sections are ordered
336 	 * as they will appear in the output image.
337 	 */
338 	if ((ofl->ofl_flags & FLG_OF_TLSPHDR) &&
339 	    (osp->os_shdr->sh_flags & SHF_TLS) &&
340 	    (list_appendc(&ofl->ofl_ostlsseg, osp) == 0))
341 		return (S_ERROR);
342 
343 	return (0);
344 }
345 
346 /*
347  * Create the elf structures that allow the input data to be associated with the
348  * new image:
349  *
350  *	o	define the new elf image using elf_begin(),
351  *
352  *	o	obtain an elf header for the image,
353  *
354  *	o	traverse the input segments and create a program header array
355  *		to define the required segments,
356  *
357  *	o 	traverse the output sections for each segment assigning a new
358  *		section descriptor and section header for each,
359  *
360  *	o	traverse the input sections associated with each output section
361  *		and assign a new data descriptor to each (each output section
362  *		becomes a linked list of input data buffers).
363  */
364 uintptr_t
365 ld_create_outfile(Ofl_desc *ofl)
366 {
367 	Listnode	*lnp1;
368 	Sg_desc		*sgp;
369 	Os_desc		**ospp;
370 	Is_desc		*isp;
371 	Elf_Data	*tlsdata = 0;
372 	Aliste		off;
373 	Word		flags = ofl->ofl_flags;
374 	size_t		ndx = 0, fndx = 0;
375 	Elf_Cmd		cmd;
376 	Boolean		fixalign = FALSE;
377 	int		fd, nseg = 0, shidx = 0, dataidx = 0, ptloadidx = 0;
378 
379 	/*
380 	 * If DF_1_NOHDR was set in map_parse() or FLG_OF1_VADDR was set,
381 	 * we need to do alignment adjustment.
382 	 */
383 	if ((ofl->ofl_flags1 & FLG_OF1_VADDR) ||
384 	    (ofl->ofl_dtflags_1 & DF_1_NOHDR)) {
385 		fixalign = TRUE;
386 	}
387 
388 	if (flags & FLG_OF_MEMORY) {
389 		cmd = ELF_C_IMAGE;
390 		fd = 0;
391 	} else {
392 		fd = ofl->ofl_fd;
393 		cmd = ELF_C_WRITE;
394 	}
395 
396 	/*
397 	 * If there are any ordered sections, handle them here.
398 	 */
399 	if ((ofl->ofl_ordered.head != NULL) &&
400 	    (ld_sort_ordered(ofl) == S_ERROR))
401 		return (S_ERROR);
402 
403 	/*
404 	 * Tell the access library about our new temporary file.
405 	 */
406 	if ((ofl->ofl_welf = elf_begin(fd, cmd, 0)) == NULL) {
407 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_BEGIN),
408 		    ofl->ofl_name);
409 		return (S_ERROR);
410 	}
411 
412 	/*
413 	 * Obtain a new Elf header.
414 	 */
415 	if ((ofl->ofl_nehdr = elf_newehdr(ofl->ofl_welf)) == NULL) {
416 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_NEWEHDR),
417 		    ofl->ofl_name);
418 		return (S_ERROR);
419 	}
420 	ofl->ofl_nehdr->e_machine = ofl->ofl_dehdr->e_machine;
421 
422 	DBG_CALL(Dbg_util_nl(ofl->ofl_lml, DBG_NL_STD));
423 	for (LIST_TRAVERSE(&ofl->ofl_segs, lnp1, sgp)) {
424 		int	frst = 0;
425 		Phdr	*phdr = &(sgp->sg_phdr);
426 		Word	ptype = phdr->p_type;
427 
428 		/*
429 		 * Count the number of segments that will go in the program
430 		 * header table. If a segment is empty, ignore it.
431 		 */
432 		if (!(flags & FLG_OF_RELOBJ)) {
433 			if (ptype == PT_PHDR) {
434 				/*
435 				 * If we are generating an interp section (and
436 				 * thus an associated PT_INTERP program header
437 				 * entry) also generate a PT_PHDR program header
438 				 * entry.  This allows the kernel to generate
439 				 * the appropriate aux vector entries to pass to
440 				 * the interpreter (refer to exec/elf/elf.c).
441 				 * Note that if an image was generated with an
442 				 * interp section, but no associated PT_PHDR
443 				 * program header entry, the kernel will simply
444 				 * pass the interpreter an open file descriptor
445 				 * when the image is executed).
446 				 */
447 				if (ofl->ofl_osinterp)
448 					nseg++;
449 			} else if (ptype == PT_INTERP) {
450 				if (ofl->ofl_osinterp)
451 					nseg++;
452 			} else if (ptype == PT_DYNAMIC) {
453 				if (flags & FLG_OF_DYNAMIC)
454 					nseg++;
455 			} else if (ptype == PT_TLS) {
456 				if (flags & FLG_OF_TLSPHDR)
457 					nseg++;
458 #if	(defined(__i386) || defined(__amd64)) && defined(_ELF64)
459 			} else if (ptype == PT_SUNW_UNWIND) {
460 				if (ofl->ofl_unwindhdr)
461 					nseg++;
462 #endif
463 			} else if (ptype == PT_SUNWBSS) {
464 				if (ofl->ofl_issunwbss)
465 					nseg++;
466 			} else if (ptype == PT_SUNWSTACK) {
467 					nseg++;
468 			} else if (ptype == PT_SUNWDTRACE) {
469 				if (ofl->ofl_dtracesym)
470 					nseg++;
471 			} else if (ptype == PT_SUNWCAP) {
472 				if (ofl->ofl_oscap)
473 					nseg++;
474 			} else if ((sgp->sg_osdescs != NULL) ||
475 			    (sgp->sg_flags & FLG_SG_EMPTY)) {
476 				if (((sgp->sg_flags & FLG_SG_EMPTY) == 0) &&
477 				    ((sgp->sg_flags & FLG_SG_PHREQ) == 0)) {
478 					/*
479 					 * If this is a segment for which
480 					 * we are not making a program header,
481 					 * don't increment nseg
482 					 */
483 					ptype = (sgp->sg_phdr).p_type = PT_NULL;
484 				} else if (ptype != PT_NULL)
485 					nseg++;
486 			}
487 		}
488 
489 		/*
490 		 * If the first loadable segment has the ?N flag,
491 		 * then ?N will be on.
492 		 */
493 		if ((ptype == PT_LOAD) && (ptloadidx == 0)) {
494 			ptloadidx++;
495 			if (sgp->sg_flags & FLG_SG_NOHDR) {
496 				fixalign = TRUE;
497 				ofl->ofl_dtflags_1 |= DF_1_NOHDR;
498 			}
499 		}
500 
501 		shidx = 0;
502 		for (ALIST_TRAVERSE(sgp->sg_osdescs, off, ospp)) {
503 			Listnode	*lnp2;
504 			Os_desc		*osp = *ospp;
505 
506 			dataidx = 0;
507 			for (LIST_TRAVERSE(&(osp->os_isdescs), lnp2, isp)) {
508 				Elf_Data *	data;
509 				Ifl_desc *	ifl = isp->is_file;
510 
511 				/*
512 				 * At this point we know whether a section has
513 				 * been referenced.  If it hasn't, and the whole
514 				 * file hasn't been referenced (which would have
515 				 * been caught in ignore_section_processing()),
516 				 * give a diagnostic (-D unused,detail) or
517 				 * discard the section if -zignore is in effect.
518 				 */
519 				if (ifl &&
520 				    (((ifl->ifl_flags & FLG_IF_FILEREF) == 0) ||
521 				    ((ptype == PT_LOAD) &&
522 				    ((isp->is_flags & FLG_IS_SECTREF) == 0) &&
523 				    (isp->is_shdr->sh_size > 0)))) {
524 					Lm_list	*lml = ofl->ofl_lml;
525 
526 					if (ifl->ifl_flags & FLG_IF_IGNORE) {
527 					    isp->is_flags |= FLG_IS_DISCARD;
528 					    DBG_CALL(Dbg_unused_sec(lml, isp));
529 					    continue;
530 					} else
531 					    DBG_CALL(Dbg_unused_sec(lml, isp));
532 				}
533 
534 				/*
535 				 * If this section provides no data, and isn't
536 				 * referenced, then it can be discarded as well.
537 				 * Note, if this is the first input section
538 				 * associated to an output section, let it
539 				 * through, there may be a legitimate reason why
540 				 * the user wants a null section.  Discarding
541 				 * additional sections is intended to remove the
542 				 * empty clutter the compilers have a habit of
543 				 * creating.  Don't provide an unused diagnostic
544 				 * as these sections aren't typically the users
545 				 * creation.
546 				 */
547 				if (ifl && dataidx &&
548 				    ((isp->is_flags & FLG_IS_SECTREF) == 0) &&
549 				    (isp->is_shdr->sh_size == 0)) {
550 					isp->is_flags |= FLG_IS_DISCARD;
551 					continue;
552 				}
553 
554 				/*
555 				 * The first input section triggers the creation
556 				 * of the associated output section.
557 				 */
558 				if (osp->os_scn == NULL) {
559 					shidx++;
560 
561 					if (create_outsec(ofl, sgp, osp, ptype,
562 					    shidx, fixalign) == S_ERROR)
563 						return (S_ERROR);
564 				}
565 
566 				dataidx++;
567 
568 				/*
569 				 * Create a new output data buffer for each
570 				 * input data buffer, thus linking the new
571 				 * buffers to the new elf output structures.
572 				 * Simply make the new data buffers point to
573 				 * the old data.
574 				 */
575 				if ((data = elf_newdata(osp->os_scn)) == NULL) {
576 					eprintf(ofl->ofl_lml, ERR_ELF,
577 					    MSG_INTL(MSG_ELF_NEWDATA),
578 					    ofl->ofl_name);
579 					return (S_ERROR);
580 				}
581 				*data = *(isp->is_indata);
582 				isp->is_indata = data;
583 
584 				if ((fixalign == TRUE) && (ptype == PT_LOAD) &&
585 				    (shidx == 1) && (dataidx == 1))
586 					data->d_align = sgp->sg_addralign;
587 
588 				/*
589 				 * Save the first TLS data buffer, as this is
590 				 * the start of the TLS segment. Realign this
591 				 * buffer based on the alignment requirements
592 				 * of all the TLS input sections.
593 				 */
594 				if ((ofl->ofl_flags & FLG_OF_TLSPHDR) &&
595 				    (isp->is_shdr->sh_flags & SHF_TLS)) {
596 					if (tlsdata == 0)
597 						tlsdata = data;
598 					tlsdata->d_align =
599 					    ld_lcm(tlsdata->d_align,
600 					    isp->is_shdr->sh_addralign);
601 				}
602 
603 #if	defined(_ELF64) && defined(_ILP32)
604 				/*
605 				 * 4106312, the 32-bit ELF64 version of ld
606 				 * needs to be able to create large .bss
607 				 * sections.  The d_size member of Elf_Data
608 				 * only allows 32-bits in _ILP32, so we build
609 				 * multiple data-items that each fit into 32-
610 				 * bits.  libelf (4106398) can summ these up
611 				 * into a 64-bit quantity.  This only works
612 				 * for NOBITS sections which don't have any
613 				 * real data to maintain and don't require
614 				 * large file support.
615 				 */
616 				if (isp->is_shdr->sh_type == SHT_NOBITS) {
617 					Xword sz = isp->is_shdr->sh_size;
618 
619 					while (sz >> 32) {
620 						data->d_size = SIZE_MAX;
621 						sz -= (Xword)SIZE_MAX;
622 
623 						data = elf_newdata(osp->os_scn);
624 						if (data == NULL)
625 							return (S_ERROR);
626 					}
627 					data->d_size = (size_t)sz;
628 				}
629 #endif
630 
631 				/*
632 				 * If this segment requires rounding realign the
633 				 * first data buffer associated with the first
634 				 * section.
635 				 */
636 				if ((frst++ == 0) &&
637 				    (sgp->sg_flags & FLG_SG_ROUND)) {
638 					Xword    align;
639 
640 					if (data->d_align)
641 						align = (Xword)
642 						    S_ROUND(data->d_align,
643 						    sgp->sg_round);
644 					else
645 						align = sgp->sg_round;
646 
647 					data->d_align = (size_t)align;
648 				}
649 			}
650 
651 			/*
652 			 * Clear the szoutrels counter so that it can be used
653 			 * again in the building of relocs.  See machrel.c.
654 			 */
655 			osp->os_szoutrels = 0;
656 		}
657 	}
658 
659 	/*
660 	 * Build an empty PHDR.
661 	 */
662 	if (nseg) {
663 		if ((ofl->ofl_phdr = elf_newphdr(ofl->ofl_welf,
664 		    nseg)) == NULL) {
665 			eprintf(ofl->ofl_lml, ERR_ELF,
666 			    MSG_INTL(MSG_ELF_NEWPHDR), ofl->ofl_name);
667 			return (S_ERROR);
668 		}
669 	}
670 
671 	/*
672 	 * If we need to generate a memory model, pad the image.
673 	 */
674 	if (flags & FLG_OF_MEMORY) {
675 		if (pad_outfile(ofl) == S_ERROR)
676 			return (S_ERROR);
677 	}
678 
679 	/*
680 	 * After all the basic input file processing, all data pointers are
681 	 * referencing two types of memory:
682 	 *
683 	 *	o	allocated memory, ie. elf structures, internal link
684 	 *		editor structures, and any new sections that have been
685 	 *		created.
686 	 *
687 	 *	o	original input file mmap'ed memory, ie. the actual data
688 	 *		sections of the input file images.
689 	 *
690 	 * Up until now, the only memory modifications have been carried out on
691 	 * the allocated memory.  Before carrying out any relocations, write the
692 	 * new output file image and reassign any necessary data pointers to the
693 	 * output files memory image.  This insures that any relocation
694 	 * modifications are made to the output file image and not to the input
695 	 * file image, thus preventing the creation of dirty pages and reducing
696 	 * the overall swap space requirement.
697 	 *
698 	 * Write out the elf structure so as to create the new file image.
699 	 */
700 	if ((ofl->ofl_size = (size_t)elf_update(ofl->ofl_welf,
701 	    ELF_C_WRIMAGE)) == (size_t)-1) {
702 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_UPDATE),
703 		    ofl->ofl_name);
704 		return (S_ERROR);
705 	}
706 
707 	/*
708 	 * Initialize the true `ofl' information with the memory images address
709 	 * and size.  This will be used to write() out the image once any
710 	 * relocation processing has been completed.  We also use this image
711 	 * information to setup a new Elf descriptor, which is used to obtain
712 	 * all the necessary elf pointers within the new output image.
713 	 */
714 	if ((ofl->ofl_elf = elf_begin(0, ELF_C_IMAGE,
715 	    ofl->ofl_welf)) == NULL) {
716 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_BEGIN),
717 		    ofl->ofl_name);
718 		return (S_ERROR);
719 	}
720 	if ((ofl->ofl_nehdr = elf_getehdr(ofl->ofl_elf)) == NULL) {
721 		eprintf(ofl->ofl_lml, ERR_ELF, MSG_INTL(MSG_ELF_GETEHDR),
722 		    ofl->ofl_name);
723 		return (S_ERROR);
724 	}
725 	if (!(flags & FLG_OF_RELOBJ))
726 		if ((ofl->ofl_phdr = elf_getphdr(ofl->ofl_elf)) == NULL) {
727 			eprintf(ofl->ofl_lml, ERR_ELF,
728 			    MSG_INTL(MSG_ELF_GETPHDR), ofl->ofl_name);
729 			return (S_ERROR);
730 		}
731 
732 	/*
733 	 * Reinitialize the section descriptors, section headers and obtain new
734 	 * output data buffer pointers (these will be used to perform any
735 	 * relocations).
736 	 */
737 	for (LIST_TRAVERSE(&ofl->ofl_segs, lnp1, sgp)) {
738 		Phdr	*_phdr = &(sgp->sg_phdr);
739 		Os_desc	**ospp;
740 		Aliste	off;
741 		Boolean	recorded = FALSE;
742 
743 		for (ALIST_TRAVERSE(sgp->sg_osdescs, off, ospp)) {
744 			Os_desc	*osp = *ospp;
745 
746 			/*
747 			 * Make sure that an output section was originally
748 			 * created.  Input sections that had been marked as
749 			 * discarded may have made an output section
750 			 * unnecessary.  Remove this alist entry so that
751 			 * future output section descriptor processing doesn't
752 			 * have to compensate for this empty section.
753 			 */
754 			if (osp->os_scn == NULL) {
755 				(void) alist_delete(sgp->sg_osdescs, 0, &off);
756 				continue;
757 			}
758 
759 			if ((osp->os_scn = elf_getscn(ofl->ofl_elf, ++ndx)) ==
760 			    NULL) {
761 				eprintf(ofl->ofl_lml, ERR_ELF,
762 				    MSG_INTL(MSG_ELF_GETSCN), ofl->ofl_name,
763 				    ndx);
764 				return (S_ERROR);
765 			}
766 			if ((osp->os_shdr = elf_getshdr(osp->os_scn)) ==
767 			    NULL) {
768 				eprintf(ofl->ofl_lml, ERR_ELF,
769 				    MSG_INTL(MSG_ELF_GETSHDR), ofl->ofl_name);
770 				return (S_ERROR);
771 			}
772 			if ((fixalign == TRUE) && (sgp->sg_fscn != 0) &&
773 			    (recorded == FALSE)) {
774 				Elf_Scn *scn;
775 
776 				scn = sgp->sg_fscn;
777 				if ((fndx = elf_ndxscn(scn)) == SHN_UNDEF) {
778 					eprintf(ofl->ofl_lml, ERR_ELF,
779 					    MSG_INTL(MSG_ELF_NDXSCN),
780 					    ofl->ofl_name);
781 					return (S_ERROR);
782 				}
783 				if (ndx == fndx) {
784 					sgp->sg_fscn = osp->os_scn;
785 					recorded = TRUE;
786 				}
787 			}
788 
789 			if ((osp->os_outdata =
790 			    elf_getdata(osp->os_scn, NULL)) == NULL) {
791 				eprintf(ofl->ofl_lml, ERR_ELF,
792 				    MSG_INTL(MSG_ELF_GETDATA), ofl->ofl_name);
793 				return (S_ERROR);
794 			}
795 
796 			/*
797 			 * If this section is part of a loadable segment insure
798 			 * that the segments alignment is appropriate.
799 			 */
800 			if (_phdr->p_type == PT_LOAD) {
801 				_phdr->p_align = ld_lcm(_phdr->p_align,
802 				    osp->os_shdr->sh_addralign);
803 			}
804 		}
805 	}
806 	return (1);
807 }
808