xref: /freebsd/cddl/contrib/opensolaris/tools/ctf/cvt/output.c (revision cb6f7225629301d3179f6e9f6d3be4d80f57a31f)
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  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * Routines for preparing tdata trees for conversion into CTF data, and
28  * for placing the resulting data into an output file.
29  */
30 
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <strings.h>
34 #include <sys/types.h>
35 #include <sys/stat.h>
36 #include <fcntl.h>
37 #include <libelf.h>
38 #include <gelf.h>
39 #include <unistd.h>
40 
41 #include "ctftools.h"
42 #include "list.h"
43 #include "memory.h"
44 #include "traverse.h"
45 #include "symbol.h"
46 
47 typedef struct iidesc_match {
48 	int iim_fuzzy;
49 	iidesc_t *iim_ret;
50 	char *iim_name;
51 	char *iim_file;
52 	uchar_t iim_bind;
53 } iidesc_match_t;
54 
55 static int
burst_iitypes(void * data,void * arg)56 burst_iitypes(void *data, void *arg)
57 {
58 	iidesc_t *ii = data;
59 	iiburst_t *iiburst = arg;
60 
61 	switch (ii->ii_type) {
62 	case II_GFUN:
63 	case II_SFUN:
64 	case II_GVAR:
65 	case II_SVAR:
66 		if (!(ii->ii_flags & IIDESC_F_USED))
67 			return (0);
68 		break;
69 	default:
70 		break;
71 	}
72 
73 	ii->ii_dtype->t_flags |= TDESC_F_ISROOT;
74 	(void) iitraverse_td(ii, iiburst->iib_tdtd);
75 	return (1);
76 }
77 
78 /*ARGSUSED1*/
79 static int
save_type_by_id(tdesc_t * tdp,tdesc_t ** tdpp __unused,void * private)80 save_type_by_id(tdesc_t *tdp, tdesc_t **tdpp __unused, void *private)
81 {
82 	iiburst_t *iiburst = private;
83 
84 	/*
85 	 * Doing this on every node is horribly inefficient, but given that
86 	 * we may be suppressing some types, we can't trust nextid in the
87 	 * tdata_t.
88 	 */
89 	if (tdp->t_id > iiburst->iib_maxtypeid)
90 		iiburst->iib_maxtypeid = tdp->t_id;
91 
92 	slist_add(&iiburst->iib_types, tdp, tdesc_idcmp);
93 
94 	return (1);
95 }
96 
97 static tdtrav_cb_f burst_types_cbs[] = {
98 	NULL,
99 	save_type_by_id,	/* intrinsic */
100 	save_type_by_id,	/* pointer */
101 	save_type_by_id,	/* array */
102 	save_type_by_id,	/* function */
103 	save_type_by_id,	/* struct */
104 	save_type_by_id,	/* union */
105 	save_type_by_id,	/* enum */
106 	save_type_by_id,	/* forward */
107 	save_type_by_id,	/* typedef */
108 	tdtrav_assert,		/* typedef_unres */
109 	save_type_by_id,	/* volatile */
110 	save_type_by_id,	/* const */
111 	save_type_by_id		/* restrict */
112 };
113 
114 
115 static iiburst_t *
iiburst_new(tdata_t * td,int max)116 iiburst_new(tdata_t *td, int max)
117 {
118 	iiburst_t *iiburst = xcalloc(sizeof (iiburst_t));
119 	iiburst->iib_td = td;
120 	iiburst->iib_funcs = xcalloc(sizeof (iidesc_t *) * max);
121 	iiburst->iib_nfuncs = 0;
122 	iiburst->iib_objts = xcalloc(sizeof (iidesc_t *) * max);
123 	iiburst->iib_nobjts = 0;
124 	return (iiburst);
125 }
126 
127 static void
iiburst_types(iiburst_t * iiburst)128 iiburst_types(iiburst_t *iiburst)
129 {
130 	tdtrav_data_t tdtd;
131 
132 	tdtrav_init(&tdtd, &iiburst->iib_td->td_curvgen, NULL, burst_types_cbs,
133 	    NULL, (void *)iiburst);
134 
135 	iiburst->iib_tdtd = &tdtd;
136 
137 	(void) hash_iter(iiburst->iib_td->td_iihash, burst_iitypes, iiburst);
138 }
139 
140 static void
iiburst_free(iiburst_t * iiburst)141 iiburst_free(iiburst_t *iiburst)
142 {
143 	free(iiburst->iib_funcs);
144 	free(iiburst->iib_objts);
145 	list_free(iiburst->iib_types, NULL, NULL);
146 	free(iiburst);
147 }
148 
149 /*
150  * See if this iidesc matches the ELF symbol data we pass in.
151  *
152  * A fuzzy match is where we have a local symbol matching the name of a
153  * global type description. This is common when a mapfile is used for a
154  * DSO, but we don't accept it by default.
155  *
156  * A weak fuzzy match is when a weak symbol was resolved and matched to
157  * a global type description.
158  */
159 static int
matching_iidesc(void * arg1,void * arg2)160 matching_iidesc(void *arg1, void *arg2)
161 {
162 	iidesc_t *iidesc = arg1;
163 	iidesc_match_t *match = arg2;
164 	if (streq(iidesc->ii_name, match->iim_name) == 0)
165 		return (0);
166 
167 	switch (iidesc->ii_type) {
168 	case II_GFUN:
169 	case II_GVAR:
170 		if (match->iim_bind == STB_GLOBAL) {
171 			match->iim_ret = iidesc;
172 			return (-1);
173 		} else if (match->iim_fuzzy && match->iim_ret == NULL) {
174 			match->iim_ret = iidesc;
175 			/* continue to look for strong match */
176 			return (0);
177 		}
178 		break;
179 	case II_SFUN:
180 	case II_SVAR:
181 		if (match->iim_bind == STB_LOCAL &&
182 		    match->iim_file != NULL &&
183 		    streq(iidesc->ii_owner, match->iim_file)) {
184 			match->iim_ret = iidesc;
185 			return (-1);
186 		}
187 		break;
188 	default:
189 		break;
190 	}
191 	return (0);
192 }
193 
194 static iidesc_t *
find_iidesc(tdata_t * td,iidesc_match_t * match)195 find_iidesc(tdata_t *td, iidesc_match_t *match)
196 {
197 	match->iim_ret = NULL;
198 	iter_iidescs_by_name(td, match->iim_name,
199 	    matching_iidesc, match);
200 	return (match->iim_ret);
201 }
202 
203 /*
204  * If we have a weak symbol, attempt to find the strong symbol it will
205  * resolve to.  Note: the code where this actually happens is in
206  * sym_process() in cmd/sgs/libld/common/syms.c
207  *
208  * Finding the matching symbol is unfortunately not trivial.  For a
209  * symbol to be a candidate, it must:
210  *
211  * - have the same type (function, object)
212  * - have the same value (address)
213  * - have the same size
214  * - not be another weak symbol
215  * - belong to the same section (checked via section index)
216  *
217  * If such a candidate is global, then we assume we've found it.  The
218  * linker generates the symbol table such that the curfile might be
219  * incorrect; this is OK for global symbols, since find_iidesc() doesn't
220  * need to check for the source file for the symbol.
221  *
222  * We might have found a strong local symbol, where the curfile is
223  * accurate and matches that of the weak symbol.  We assume this is a
224  * reasonable match.
225  *
226  * If we've got a local symbol with a non-matching curfile, there are
227  * two possibilities.  Either this is a completely different symbol, or
228  * it's a once-global symbol that was scoped to local via a mapfile.  In
229  * the latter case, curfile is likely inaccurate since the linker does
230  * not preserve the needed curfile in the order of the symbol table (see
231  * the comments about locally scoped symbols in libld's update_osym()).
232  * As we can't tell this case from the former one, we use this symbol
233  * iff no other matching symbol is found.
234  *
235  * What we really need here is a SUNW section containing weak<->strong
236  * mappings that we can consume.
237  */
238 static int
check_for_weak(GElf_Sym * weak,char const * weakfile,Elf_Data * data,int nent,Elf_Data * strdata,GElf_Sym * retsym,char ** curfilep)239 check_for_weak(GElf_Sym *weak, char const *weakfile,
240     Elf_Data *data, int nent, Elf_Data *strdata,
241     GElf_Sym *retsym, char **curfilep)
242 {
243 	char *curfile = NULL;
244 	char *tmpfile1 = NULL;
245 	GElf_Sym tmpsym;
246 	int candidate = 0;
247 	int i;
248 	tmpsym.st_info = 0;
249 	tmpsym.st_name = 0;
250 
251 	if (GELF_ST_BIND(weak->st_info) != STB_WEAK)
252 		return (0);
253 
254 	for (i = 0; i < nent; i++) {
255 		GElf_Sym sym;
256 		uchar_t type;
257 
258 		if (gelf_getsym(data, i, &sym) == NULL)
259 			continue;
260 
261 		type = GELF_ST_TYPE(sym.st_info);
262 
263 		if (type == STT_FILE)
264 			curfile = (char *)strdata->d_buf + sym.st_name;
265 
266 		if (GELF_ST_TYPE(weak->st_info) != type ||
267 		    weak->st_value != sym.st_value)
268 			continue;
269 
270 		if (weak->st_size != sym.st_size)
271 			continue;
272 
273 		if (GELF_ST_BIND(sym.st_info) == STB_WEAK)
274 			continue;
275 
276 		if (sym.st_shndx != weak->st_shndx)
277 			continue;
278 
279 		if (GELF_ST_BIND(sym.st_info) == STB_LOCAL &&
280 		    (curfile == NULL || weakfile == NULL ||
281 		    strcmp(curfile, weakfile) != 0)) {
282 			candidate = 1;
283 			tmpfile1 = curfile;
284 			tmpsym = sym;
285 			continue;
286 		}
287 
288 		*curfilep = curfile;
289 		*retsym = sym;
290 		return (1);
291 	}
292 
293 	if (candidate) {
294 		*curfilep = tmpfile1;
295 		*retsym = tmpsym;
296 		return (1);
297 	}
298 
299 	return (0);
300 }
301 
302 /*
303  * When we've found the underlying symbol's type description
304  * for a weak symbol, we need to copy it and rename it to match
305  * the weak symbol. We also need to add it to the td so it's
306  * handled along with the others later.
307  */
308 static iidesc_t *
copy_from_strong(tdata_t * td,GElf_Sym * sym,iidesc_t * strongdesc,const char * weakname,const char * weakfile)309 copy_from_strong(tdata_t *td, GElf_Sym *sym, iidesc_t *strongdesc,
310     const char *weakname, const char *weakfile)
311 {
312 	iidesc_t *new = iidesc_dup_rename(strongdesc, weakname, weakfile);
313 	uchar_t type = GELF_ST_TYPE(sym->st_info);
314 
315 	switch (type) {
316 	case STT_OBJECT:
317 		new->ii_type = II_GVAR;
318 		break;
319 	case STT_FUNC:
320 		new->ii_type = II_GFUN;
321 		break;
322 	}
323 
324 	hash_add(td->td_iihash, new);
325 
326 	return (new);
327 }
328 
329 /*
330  * Process the symbol table of the output file, associating each symbol
331  * with a type description if possible, and sorting them into functions
332  * and data, maintaining symbol table order.
333  */
334 static iiburst_t *
sort_iidescs(Elf * elf,const char * file,tdata_t * td,int fuzzymatch,int dynsym)335 sort_iidescs(Elf *elf, const char *file, tdata_t *td, int fuzzymatch,
336     int dynsym)
337 {
338 	iiburst_t *iiburst;
339 	Elf_Scn *scn;
340 	GElf_Shdr shdr;
341 	Elf_Data *data, *strdata;
342 	int i, stidx;
343 	int nent;
344 	iidesc_match_t match;
345 
346 	match.iim_fuzzy = fuzzymatch;
347 	match.iim_file = NULL;
348 
349 	if ((stidx = findelfsecidx(elf, file,
350 	    dynsym ? ".dynsym" : ".symtab")) < 0)
351 		terminate("%s: Can't open symbol table\n", file);
352 	scn = elf_getscn(elf, stidx);
353 	data = elf_getdata(scn, NULL);
354 	gelf_getshdr(scn, &shdr);
355 	nent = shdr.sh_size / shdr.sh_entsize;
356 
357 	scn = elf_getscn(elf, shdr.sh_link);
358 	strdata = elf_getdata(scn, NULL);
359 
360 	iiburst = iiburst_new(td, nent);
361 
362 	for (i = 0; i < nent; i++) {
363 		GElf_Sym sym;
364 		char *bname;
365 		iidesc_t **tolist;
366 		GElf_Sym ssym;
367 		iidesc_match_t smatch;
368 		int *curr;
369 		iidesc_t *iidesc;
370 
371 		if (gelf_getsym(data, i, &sym) == NULL)
372 			elfterminate(file, "Couldn't read symbol %d", i);
373 
374 		match.iim_name = (char *)strdata->d_buf + sym.st_name;
375 		match.iim_bind = GELF_ST_BIND(sym.st_info);
376 
377 		switch (GELF_ST_TYPE(sym.st_info)) {
378 		case STT_FILE:
379 			bname = strrchr(match.iim_name, '/');
380 			match.iim_file = bname == NULL ? match.iim_name : bname + 1;
381 			continue;
382 		case STT_OBJECT:
383 			tolist = iiburst->iib_objts;
384 			curr = &iiburst->iib_nobjts;
385 			break;
386 		case STT_FUNC:
387 			tolist = iiburst->iib_funcs;
388 			curr = &iiburst->iib_nfuncs;
389 			break;
390 		default:
391 			continue;
392 		}
393 
394 		if (ignore_symbol(&sym, match.iim_name))
395 			continue;
396 
397 		iidesc = find_iidesc(td, &match);
398 
399 		if (iidesc != NULL) {
400 			tolist[*curr] = iidesc;
401 			iidesc->ii_flags |= IIDESC_F_USED;
402 			(*curr)++;
403 			continue;
404 		}
405 
406 		if (!check_for_weak(&sym, match.iim_file, data, nent, strdata,
407 		    &ssym, &smatch.iim_file)) {
408 			(*curr)++;
409 			continue;
410 		}
411 
412 		smatch.iim_fuzzy = fuzzymatch;
413 		smatch.iim_name = (char *)strdata->d_buf + ssym.st_name;
414 		smatch.iim_bind = GELF_ST_BIND(ssym.st_info);
415 
416 		debug(3, "Weak symbol %s resolved to %s\n", match.iim_name,
417 		    smatch.iim_name);
418 
419 		iidesc = find_iidesc(td, &smatch);
420 
421 		if (iidesc != NULL) {
422 			tolist[*curr] = copy_from_strong(td, &sym,
423 			    iidesc, match.iim_name, match.iim_file);
424 			tolist[*curr]->ii_flags |= IIDESC_F_USED;
425 		}
426 
427 		(*curr)++;
428 	}
429 
430 	/*
431 	 * Stabs are generated for every function declared in a given C source
432 	 * file.  When converting an object file, we may encounter a stab that
433 	 * has no symbol table entry because the optimizer has decided to omit
434 	 * that item (for example, an unreferenced static function).  We may
435 	 * see iidescs that do not have an associated symtab entry, and so
436 	 * we do not write records for those functions into the CTF data.
437 	 * All others get marked as a root by this function.
438 	 */
439 	iiburst_types(iiburst);
440 
441 	/*
442 	 * By not adding some of the functions and/or objects, we may have
443 	 * caused some types that were referenced solely by those
444 	 * functions/objects to be suppressed.  This could cause a label,
445 	 * generated prior to the evisceration, to be incorrect.  Find the
446 	 * highest type index, and change the label indicies to be no higher
447 	 * than this value.
448 	 */
449 	tdata_label_newmax(td, iiburst->iib_maxtypeid);
450 
451 	return (iiburst);
452 }
453 
454 static void
write_file(Elf * src,const char * srcname,Elf * dst,const char * dstname,caddr_t ctfdata,size_t ctfsize,int flags)455 write_file(Elf *src, const char *srcname, Elf *dst, const char *dstname,
456     caddr_t ctfdata, size_t ctfsize, int flags)
457 {
458 	GElf_Ehdr sehdr, dehdr;
459 	Elf_Scn *sscn, *dscn;
460 	Elf_Data *sdata, *ddata;
461 	GElf_Shdr shdr;
462 	GElf_Word symtab_type;
463 	int symtab_idx = -1;
464 	off_t new_offset = 0;
465 	off_t ctfnameoff = 0;
466 	int dynsym = (flags & CTF_USE_DYNSYM);
467 	int keep_stabs = (flags & CTF_KEEP_STABS);
468 	int *secxlate;
469 	int srcidx, dstidx;
470 	int changing = 0;
471 	int pad;
472 	int i;
473 
474 	if (gelf_newehdr(dst, gelf_getclass(src)) == NULL)
475 		elfterminate(dstname, "Cannot copy ehdr to temp file");
476 	gelf_getehdr(src, &sehdr);
477 	memcpy(&dehdr, &sehdr, sizeof (GElf_Ehdr));
478 	gelf_update_ehdr(dst, &dehdr);
479 
480 	symtab_type = dynsym ? SHT_DYNSYM : SHT_SYMTAB;
481 
482 	/*
483 	 * Neither the existing stab sections nor the SUNW_ctf sections (new or
484 	 * existing) are SHF_ALLOC'd, so they won't be in areas referenced by
485 	 * program headers.  As such, we can just blindly copy the program
486 	 * headers from the existing file to the new file.
487 	 */
488 	if (sehdr.e_phnum != 0) {
489 		(void) elf_flagelf(dst, ELF_C_SET, ELF_F_LAYOUT);
490 		if (gelf_newphdr(dst, sehdr.e_phnum) == NULL)
491 			elfterminate(dstname, "Cannot make phdrs in temp file");
492 
493 		for (i = 0; i < sehdr.e_phnum; i++) {
494 			GElf_Phdr phdr;
495 
496 			gelf_getphdr(src, i, &phdr);
497 			gelf_update_phdr(dst, i, &phdr);
498 		}
499 	}
500 
501 	secxlate = xmalloc(sizeof (int) * sehdr.e_shnum);
502 	for (srcidx = dstidx = 0; srcidx < sehdr.e_shnum; srcidx++) {
503 		Elf_Scn *scn = elf_getscn(src, srcidx);
504 		GElf_Shdr shdr1;
505 		char *sname;
506 
507 		gelf_getshdr(scn, &shdr1);
508 		sname = elf_strptr(src, sehdr.e_shstrndx, shdr1.sh_name);
509 		if (sname == NULL) {
510 			elfterminate(srcname, "Can't find string at %u",
511 			    shdr1.sh_name);
512 		}
513 
514 		if (strcmp(sname, CTF_ELF_SCN_NAME) == 0) {
515 			secxlate[srcidx] = -1;
516 		} else if (!keep_stabs &&
517 		    (strncmp(sname, ".stab", 5) == 0 ||
518 		    strncmp(sname, ".debug", 6) == 0 ||
519 		    strncmp(sname, ".rel.debug", 10) == 0 ||
520 		    strncmp(sname, ".rela.debug", 11) == 0)) {
521 			secxlate[srcidx] = -1;
522 		} else if (dynsym && shdr1.sh_type == SHT_SYMTAB) {
523 			/*
524 			 * If we're building CTF against the dynsym,
525 			 * we'll rip out the symtab so debuggers aren't
526 			 * confused.
527 			 */
528 			secxlate[srcidx] = -1;
529 		} else {
530 			secxlate[srcidx] = dstidx++;
531 		}
532 
533 		new_offset = (off_t)dehdr.e_phoff;
534 	}
535 
536 	for (srcidx = 1; srcidx < sehdr.e_shnum; srcidx++) {
537 		char *sname;
538 
539 		sscn = elf_getscn(src, srcidx);
540 		gelf_getshdr(sscn, &shdr);
541 
542 		if (secxlate[srcidx] == -1) {
543 			changing = 1;
544 			continue;
545 		}
546 
547 		dscn = elf_newscn(dst);
548 
549 		/*
550 		 * If this file has program headers, we need to explicitly lay
551 		 * out sections.  If none of the sections prior to this one have
552 		 * been removed, then we can just use the existing location.  If
553 		 * one or more sections have been changed, then we need to
554 		 * adjust this one to avoid holes.
555 		 */
556 		if (changing && sehdr.e_phnum != 0) {
557 			pad = new_offset % shdr.sh_addralign;
558 
559 			if (pad)
560 				new_offset += shdr.sh_addralign - pad;
561 			shdr.sh_offset = new_offset;
562 		}
563 
564 		shdr.sh_link = secxlate[shdr.sh_link];
565 
566 		if (shdr.sh_type == SHT_REL || shdr.sh_type == SHT_RELA)
567 			shdr.sh_info = secxlate[shdr.sh_info];
568 
569 		sname = elf_strptr(src, sehdr.e_shstrndx, shdr.sh_name);
570 		if (sname == NULL) {
571 			elfterminate(srcname, "Can't find string at %u",
572 			    shdr.sh_name);
573 		}
574 
575 #ifndef illumos
576 		if (gelf_update_shdr(dscn, &shdr) == 0)
577 			elfterminate(dstname, "Cannot update sect %s", sname);
578 #endif
579 
580 		if ((sdata = elf_getdata(sscn, NULL)) == NULL)
581 			elfterminate(srcname, "Cannot get sect %s data", sname);
582 		if ((ddata = elf_newdata(dscn)) == NULL)
583 			elfterminate(dstname, "Can't make sect %s data", sname);
584 #ifdef illumos
585 		bcopy(sdata, ddata, sizeof (Elf_Data));
586 #else
587 		/*
588 		 * FreeBSD's Elf_Data has private fields which the
589 		 * elf_* routines manage. Simply copying the
590 		 * entire structure corrupts the data. So we need
591 		 * to copy the public fields explictly.
592 		 */
593 		ddata->d_align = sdata->d_align;
594 		ddata->d_off = sdata->d_off;
595 		ddata->d_size = sdata->d_size;
596 		ddata->d_type = sdata->d_type;
597 		ddata->d_version = sdata->d_version;
598 #endif
599 
600 		if (srcidx == sehdr.e_shstrndx) {
601 			char seclen = strlen(CTF_ELF_SCN_NAME);
602 
603 			ddata->d_buf = xmalloc(ddata->d_size + shdr.sh_size +
604 			    seclen + 1);
605 			bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size);
606 			strcpy((caddr_t)ddata->d_buf + shdr.sh_size,
607 			    CTF_ELF_SCN_NAME);
608 			ctfnameoff = (off_t)shdr.sh_size;
609 			shdr.sh_size += seclen + 1;
610 			ddata->d_size += seclen + 1;
611 
612 			if (sehdr.e_phnum != 0)
613 				changing = 1;
614 		}
615 
616 		if (shdr.sh_type == symtab_type && shdr.sh_entsize != 0) {
617 			int nsym = shdr.sh_size / shdr.sh_entsize;
618 
619 			symtab_idx = secxlate[srcidx];
620 
621 			ddata->d_buf = xmalloc(shdr.sh_size);
622 			bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size);
623 
624 			for (i = 0; i < nsym; i++) {
625 				GElf_Sym sym;
626 				short newscn;
627 
628 				if (gelf_getsym(ddata, i, &sym) == NULL)
629 					printf("Could not get symbol %d\n",i);
630 
631 				if (sym.st_shndx >= SHN_LORESERVE)
632 					continue;
633 
634 				if ((newscn = secxlate[sym.st_shndx]) !=
635 				    sym.st_shndx) {
636 					sym.st_shndx =
637 					    (newscn == -1 ? 1 : newscn);
638 
639 					gelf_update_sym(ddata, i, &sym);
640 				}
641 			}
642 		}
643 
644 #ifndef illumos
645 		if (ddata->d_buf == NULL && sdata->d_buf != NULL) {
646 			ddata->d_buf = xmalloc(shdr.sh_size);
647 			bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size);
648 		}
649 #endif
650 
651 		if (gelf_update_shdr(dscn, &shdr) == 0)
652 			elfterminate(dstname, "Cannot update sect %s", sname);
653 
654 		new_offset = (off_t)shdr.sh_offset;
655 		if (shdr.sh_type != SHT_NOBITS)
656 			new_offset += shdr.sh_size;
657 	}
658 
659 	if (symtab_idx == -1) {
660 		terminate("%s: Cannot find %s section\n", srcname,
661 		    dynsym ? "SHT_DYNSYM" : "SHT_SYMTAB");
662 	}
663 
664 	/* Add the ctf section */
665 	dscn = elf_newscn(dst);
666 	gelf_getshdr(dscn, &shdr);
667 	shdr.sh_name = ctfnameoff;
668 	shdr.sh_type = SHT_PROGBITS;
669 	shdr.sh_size = ctfsize;
670 	shdr.sh_link = symtab_idx;
671 	shdr.sh_addralign = 4;
672 	if (changing && sehdr.e_phnum != 0) {
673 		pad = new_offset % shdr.sh_addralign;
674 
675 		if (pad)
676 			new_offset += shdr.sh_addralign - pad;
677 
678 		shdr.sh_offset = new_offset;
679 		new_offset += shdr.sh_size;
680 	}
681 
682 	ddata = elf_newdata(dscn);
683 	ddata->d_buf = ctfdata;
684 	ddata->d_size = ctfsize;
685 	ddata->d_align = shdr.sh_addralign;
686 	ddata->d_off = 0;
687 
688 	gelf_update_shdr(dscn, &shdr);
689 
690 	/* update the section header location */
691 	if (sehdr.e_phnum != 0) {
692 		size_t align = gelf_fsize(dst, ELF_T_ADDR, 1, EV_CURRENT);
693 		size_t r = new_offset % align;
694 
695 		if (r)
696 			new_offset += align - r;
697 
698 		dehdr.e_shoff = new_offset;
699 	}
700 
701 	/* commit to disk */
702 	dehdr.e_shstrndx = secxlate[sehdr.e_shstrndx];
703 	gelf_update_ehdr(dst, &dehdr);
704 	if (elf_update(dst, ELF_C_WRITE) < 0)
705 		elfterminate(dstname, "Cannot finalize temp file");
706 
707 	free(secxlate);
708 }
709 
710 static caddr_t
make_ctf_data(tdata_t * td,Elf * elf,const char * file,size_t * lenp,int flags)711 make_ctf_data(tdata_t *td, Elf *elf, const char *file, size_t *lenp, int flags)
712 {
713 	iiburst_t *iiburst;
714 	caddr_t data;
715 
716 	iiburst = sort_iidescs(elf, file, td, flags & CTF_FUZZY_MATCH,
717 	    flags & CTF_USE_DYNSYM);
718 	data = ctf_gen(iiburst, lenp, flags & (CTF_COMPRESS |  CTF_SWAP_BYTES));
719 
720 	iiburst_free(iiburst);
721 
722 	return (data);
723 }
724 
725 void
write_ctf(tdata_t * td,const char * curname,const char * newname,int flags)726 write_ctf(tdata_t *td, const char *curname, const char *newname, int flags)
727 {
728 	struct stat st;
729 	Elf *elf = NULL;
730 	Elf *telf = NULL;
731 	GElf_Ehdr ehdr;
732 	caddr_t data;
733 	size_t len;
734 	int fd = -1;
735 	int tfd = -1;
736 	int byteorder;
737 
738 	(void) elf_version(EV_CURRENT);
739 	if ((fd = open(curname, O_RDONLY)) < 0 || fstat(fd, &st) < 0)
740 		terminate("%s: Cannot open for re-reading", curname);
741 	if ((elf = elf_begin(fd, ELF_C_READ, NULL)) == NULL)
742 		elfterminate(curname, "Cannot re-read");
743 
744 	if ((tfd = open(newname, O_RDWR | O_CREAT | O_TRUNC, st.st_mode)) < 0)
745 		terminate("Cannot open temp file %s for writing", newname);
746 	if ((telf = elf_begin(tfd, ELF_C_WRITE, NULL)) == NULL)
747 		elfterminate(curname, "Cannot write");
748 
749 	if (gelf_getehdr(elf, &ehdr)) {
750 #if BYTE_ORDER == _BIG_ENDIAN
751 		byteorder = ELFDATA2MSB;
752 #else
753 		byteorder = ELFDATA2LSB;
754 #endif
755 		/*
756 		 * If target and host has the same byte order
757 		 * clear byte swapping request
758 		 */
759 		if  (ehdr.e_ident[EI_DATA] == byteorder)
760 			flags &= ~CTF_SWAP_BYTES;
761 	}
762 	else
763 		elfterminate(curname, "Failed to get EHDR");
764 
765 	data = make_ctf_data(td, elf, curname, &len, flags);
766 	write_file(elf, curname, telf, newname, data, len, flags);
767 	free(data);
768 
769 	elf_end(telf);
770 	elf_end(elf);
771 	(void) close(fd);
772 	(void) close(tfd);
773 }
774