xref: /illumos-gate/usr/src/uts/common/fs/objfs/objfs_data.c (revision dd72704bd9e794056c558153663c739e2012d721)
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 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <fs/fs_subr.h>
27 
28 #include <sys/elf.h>
29 #include <sys/errno.h>
30 #include <sys/file.h>
31 #include <sys/kmem.h>
32 #include <sys/kobj.h>
33 #include <sys/objfs.h>
34 #include <sys/objfs_impl.h>
35 #include <sys/stat.h>
36 #include <sys/systm.h>
37 #include <sys/sysmacros.h>
38 #include <sys/vfs_opreg.h>
39 
40 /*
41  * /system/object/<obj>/object
42  *
43  * This is an ELF file that contains information about data stored in the
44  * kernel.  We use a special ELF file type, ET_SUNWPSEUDO, so that we can
45  * control which fields and sections have meaning.  The file contains the
46  * following sections:
47  *
48  * 	.shstrtab	Section header string table
49  * 	.SUNW_ctf	CTF data
50  * 	.symtab		Symbol table
51  * 	.strtab		String table
52  * 	.text		Text
53  * 	.data		Data
54  * 	.bss		BSS
55  * 	.filename	Filename of module
56  * 	.info		Private module info structure
57  *
58  * The .text, .data, and .bss sections are all marked SHT_NOBITS, and the data
59  * is not actually exported in the file for security reasons.  The section
60  * headers do contain the address and size of the sections, which is needed by
61  * DTrace.  The CTF data, symbol table, and string table are present only if
62  * they exist in the kernel.
63  */
64 
65 typedef enum {
66 	SECT_TYPE_DATA,
67 	SECT_TYPE_SHSTRTAB,
68 	SECT_TYPE_DUMMY,
69 	SECT_TYPE_SYMTAB,
70 	SECT_TYPE_STRTAB,
71 	SECT_TYPE_FILENAME,
72 	SECT_TYPE_INFO
73 } sect_type_t;
74 
75 typedef struct section_desc {
76 	sect_type_t	sect_id;
77 	const char	*sect_name;
78 	uintptr_t	sect_addr;
79 	size_t		sect_size;
80 	int		sect_type;
81 	int		sect_flags;
82 	size_t		sect_str;
83 	int		sect_link;
84 	int		sect_entsize;
85 	int		sect_align;
86 } section_desc_t;
87 
88 /*
89  * For data sections, 'addr' and 'size' refer to offsets within the module
90  * structure where we can find the address and size of the section.
91  */
92 #define	SECT_DATA(name, addr, size, type, flags, align) \
93 	{ SECT_TYPE_DATA, name, offsetof(struct module, addr), \
94 	offsetof(struct module, size), type, flags, 0, 0, 0, align }
95 
96 /*
97  * The dummy section is the initial section of the file.  It is put into this
98  * array only for convenience when reading the file.
99  */
100 #define	SECT_DUMMY	{ SECT_TYPE_DUMMY, "", 0, 0, 0, 0, 0, 0, 0, 0 }
101 
102 /*
103  * The size of the symbol table and string table are not immediately available
104  * as an offset into the module struct, so we have to create individual types
105  * for each.
106  */
107 #ifdef _LP64
108 #define	SECT_SYMTAB(name, type, flags) \
109 	{ SECT_TYPE_SYMTAB, name, offsetof(struct module, symtbl), 0, type, \
110 	flags, 0, 0, sizeof (Elf64_Sym), sizeof (uint64_t) }
111 #else
112 #define	SECT_SYMTAB(name, type, flags) \
113 	{ SECT_TYPE_SYMTAB, name, offsetof(struct module, symtbl), 0, type, \
114 	flags, 0, 0, sizeof (Elf32_Sym), sizeof (uint32_t) }
115 #endif
116 #define	SECT_STRTAB(name, type, flags) \
117 	{ SECT_TYPE_STRTAB, name, offsetof(struct module, strings), 0, type, \
118 	flags, 0, 0, 0, 1 }
119 
120 /*
121  * The .shstrtab section is constructed when the module is first loaded.
122  */
123 #define	SECT_SHSTRTAB(name, type, flags) \
124 	{ SECT_TYPE_SHSTRTAB, name, 0, 0, type, flags, 0, 0, 0, 1 }
125 
126 /*
127  * Generic module information (objfs_info_t)
128  */
129 #define	SECT_INFO	\
130 	{ SECT_TYPE_INFO, ".info", 0, 0, SHT_PROGBITS, 0, 0, 0, 0, \
131 	sizeof (uint32_t) }
132 
133 /*
134  * Filename section.
135  */
136 #define	SECT_FILENAME	\
137 	{ SECT_TYPE_FILENAME, ".filename", 0, 0, SHT_PROGBITS, 0, 0, 0, 0, 1 }
138 
139 static section_desc_t data_sections[] = {
140 	SECT_DUMMY,
141 	SECT_SHSTRTAB(".shstrtab",
142 	    SHT_STRTAB, SHF_STRINGS),
143 	SECT_DATA(".SUNW_ctf", ctfdata, ctfsize,
144 	    SHT_PROGBITS, 0, sizeof (uint64_t)),
145 	SECT_SYMTAB(".symtab", SHT_SYMTAB, 0),
146 	SECT_STRTAB(".strtab", SHT_STRTAB, SHF_STRINGS),
147 	SECT_DATA(".text", text, text_size,
148 	    SHT_NOBITS, SHF_ALLOC | SHF_EXECINSTR, 0),
149 	SECT_DATA(".data", data, data_size,
150 	    SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0),
151 	SECT_DATA(".bss", bss, bss_size,
152 	    SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0),
153 	SECT_INFO,
154 	SECT_FILENAME
155 };
156 
157 #define	NSECTIONS	\
158 	(sizeof (data_sections) / sizeof (section_desc_t))
159 
160 #ifdef _LP64
161 #define	SECTION_OFFSET(section)	\
162 	(sizeof (Elf64_Ehdr) + (section) * sizeof (Elf64_Shdr))
163 #else
164 #define	SECTION_OFFSET(section)	\
165 	(sizeof (Elf32_Ehdr) + (section) * sizeof (Elf32_Shdr))
166 #endif
167 
168 /*
169  * Given a data node, returns the struct module appropriately locked.  If the
170  * object has been unloaded, or re-loaded since the file was first opened, this
171  * function will return NULL.  If successful, the caller must call
172  * objfs_data_unlock().
173  */
174 struct module *
175 objfs_data_lock(vnode_t *vp)
176 {
177 	objfs_datanode_t *dnode = vp->v_data;
178 	objfs_odirnode_t *odir = gfs_file_parent(vp)->v_data;
179 	struct modctl *mp = odir->objfs_odir_modctl;
180 
181 	(void) mod_hold_by_modctl(mp, MOD_WAIT_FOREVER | MOD_LOCK_NOT_HELD);
182 
183 	if (mp->mod_mp == NULL ||
184 	    dnode->objfs_data_gencount < mp->mod_gencount) {
185 		mod_release_mod(mp);
186 		return (NULL);
187 	}
188 
189 	return (mp->mod_mp);
190 }
191 
192 void
193 objfs_data_unlock(vnode_t *vp)
194 {
195 	objfs_odirnode_t *odir = gfs_file_parent(vp)->v_data;
196 
197 	mod_release_mod(odir->objfs_odir_modctl);
198 }
199 
200 
201 /*
202  * Called when the filesystem is first loaded.  Creates and initializes the
203  * section header string table, and fills in the sect_str members of the section
204  * descriptors.  This information could be encoded at compile-time, but this
205  * way keeps the code more maintainable, as we don't have to worry about
206  * duplicating information.
207  */
208 void
209 objfs_data_init(void)
210 {
211 	int i, shstrtab, strtab, symtab;
212 	size_t len = 0;
213 	section_desc_t *sect;
214 	char *strdata;
215 
216 	for (i = 0; i < NSECTIONS; i++) {
217 		sect = &data_sections[i];
218 
219 		ASSERT(sect->sect_align == 0 || ISP2(sect->sect_align));
220 		ASSERT(sect->sect_align <= sizeof (uint64_t));
221 
222 		len += strlen(sect->sect_name) + 1;
223 		if (strcmp(sect->sect_name, ".shstrtab") == 0)
224 			shstrtab = i;
225 		else if (strcmp(sect->sect_name, ".symtab") == 0)
226 			symtab = i;
227 		else if (strcmp(sect->sect_name, ".strtab") == 0)
228 			strtab = i;
229 	}
230 
231 	strdata = kmem_zalloc(len, KM_SLEEP);
232 	sect = &data_sections[shstrtab];
233 	sect->sect_addr = (uintptr_t)strdata;
234 	sect->sect_size = len;
235 
236 	len = 0;
237 	for (i = 0; i < NSECTIONS; i++) {
238 		sect = &data_sections[i];
239 		sect->sect_str = len;
240 		bcopy(sect->sect_name, strdata + len,
241 		    strlen(sect->sect_name) + 1);
242 		len += strlen(sect->sect_name) + 1;
243 
244 		if (strcmp(sect->sect_name, ".SUNW_ctf") == 0)
245 			sect->sect_link = symtab;
246 		else if (strcmp(sect->sect_name, ".symtab") == 0)
247 			sect->sect_link = strtab;
248 	}
249 }
250 
251 /*
252  * Given a section descriptor and module pointer, return the address of the
253  * data.
254  */
255 static uintptr_t
256 sect_addr(section_desc_t *sp, struct module *mp)
257 {
258 	uintptr_t addr;
259 
260 	switch (sp->sect_id) {
261 	case SECT_TYPE_DUMMY:
262 		addr = 0;
263 		break;
264 
265 	case SECT_TYPE_SHSTRTAB:
266 		addr = sp->sect_addr;
267 		break;
268 
269 	case SECT_TYPE_STRTAB:
270 	case SECT_TYPE_SYMTAB:
271 	case SECT_TYPE_DATA:
272 		addr = *((uintptr_t *)((char *)mp + sp->sect_addr));
273 		break;
274 
275 	case SECT_TYPE_FILENAME:
276 		addr = (uintptr_t)mp->filename;
277 		break;
278 
279 	case SECT_TYPE_INFO:
280 		addr = 1;	/* This can be anything nonzero */
281 		break;
282 	}
283 
284 	return (addr);
285 }
286 
287 /*
288  * Given a section descriptor and module pointer, return the size of the data.
289  */
290 static size_t
291 sect_size(section_desc_t *sp, struct module *mp)
292 {
293 	size_t size;
294 
295 	switch (sp->sect_id) {
296 	case SECT_TYPE_DUMMY:
297 		size = 0;
298 		break;
299 
300 	case SECT_TYPE_SHSTRTAB:
301 		size = sp->sect_size;
302 		break;
303 
304 	case SECT_TYPE_DATA:
305 		size = *((size_t *)((char *)mp + sp->sect_size));
306 		break;
307 
308 	case SECT_TYPE_SYMTAB:
309 		size = mp->symhdr->sh_size;
310 		break;
311 
312 	case SECT_TYPE_STRTAB:
313 		size = mp->strhdr->sh_size;
314 		break;
315 
316 	case SECT_TYPE_INFO:
317 		size = sizeof (objfs_info_t);
318 		break;
319 
320 	case SECT_TYPE_FILENAME:
321 		if (mp->filename == NULL)
322 			size = 0;
323 		else
324 			size = strlen(mp->filename) + 1;
325 	}
326 
327 	return (size);
328 }
329 
330 /*
331  * Given a section descriptor and module pointer, return 1 if the section has
332  * valid data and should be included, 0 otherwise.
333  */
334 static int
335 sect_valid(section_desc_t *sp, struct module *mp)
336 {
337 	if (sp->sect_id == SECT_TYPE_DUMMY ||
338 	    sect_addr(sp, mp) != 0)
339 		return (1);
340 
341 	return (0);
342 }
343 
344 /*
345  * Given a section descriptor and module pointer, return the offset into the
346  * file where the data should be placed.
347  */
348 static size_t
349 data_offset(section_desc_t *sp, struct module *mp)
350 {
351 	int i;
352 	size_t len;
353 	section_desc_t *cp;
354 
355 	if (sp != NULL && mp != NULL && !sect_valid(sp, mp))
356 		return (0);
357 
358 #ifdef _LP64
359 	len = sizeof (Elf64_Ehdr);
360 #else
361 	len = sizeof (Elf32_Ehdr);
362 #endif
363 
364 	/*
365 	 * Do a first pass to account for all the section headers.
366 	 */
367 	for (i = 0; i < NSECTIONS; i++) {
368 		if (sect_valid(&data_sections[i], mp)) {
369 #ifdef _LP64
370 			len += sizeof (Elf64_Shdr);
371 #else
372 			len += sizeof (Elf32_Shdr);
373 #endif
374 		}
375 	}
376 
377 	/*
378 	 * Add length of each section until we find the one we're looking for.
379 	 */
380 	for (i = 0; i < NSECTIONS; i++) {
381 		cp = &data_sections[i];
382 
383 		/*
384 		 * Align the section only if it's valid and contains data.  When
385 		 * searching for a specific section, align the section before
386 		 * breaking out of the loop.
387 		 */
388 		if (sect_valid(cp, mp) && cp->sect_type != SHT_NOBITS) {
389 			if (cp->sect_align > 1)
390 				len = P2ROUNDUP(len, cp->sect_align);
391 
392 			if (sp != cp)
393 				len += sect_size(cp, mp);
394 		}
395 
396 		if (sp == cp)
397 			break;
398 	}
399 
400 	return (len);
401 }
402 
403 /*
404  * Given an index into the section table and a module pointer, returns the
405  * data offset of the next section.
406  */
407 static size_t
408 next_offset(int idx, struct module *mp)
409 {
410 	int i;
411 
412 	for (i = idx + 1; i < NSECTIONS; i++) {
413 		if (sect_valid(&data_sections[i], mp))
414 			return (data_offset(&data_sections[i], mp));
415 	}
416 
417 	return (data_offset(NULL, mp));
418 }
419 
420 /*
421  * Given a module pointer, return the total size needed for the file.
422  */
423 static size_t
424 data_size(struct module *mp)
425 {
426 	return (data_offset(NULL, mp));
427 }
428 
429 /*
430  * Returns the size needed for all the headers in the file.
431  */
432 static size_t
433 header_size(void)
434 {
435 	return (data_offset(&data_sections[0], NULL));
436 }
437 
438 /* ARGSUSED */
439 vnode_t *
440 objfs_create_data(vnode_t *pvp)
441 {
442 	objfs_odirnode_t *onode = pvp->v_data;
443 	vnode_t *vp = gfs_file_create(sizeof (objfs_datanode_t), pvp,
444 	    objfs_ops_data);
445 	objfs_datanode_t *dnode = vp->v_data;
446 
447 	dnode->objfs_data_gencount = onode->objfs_odir_modctl->mod_gencount;
448 	dnode->objfs_data_info.objfs_info_primary =
449 	    onode->objfs_odir_modctl->mod_prim;
450 
451 	return (vp);
452 }
453 
454 /* ARGSUSED */
455 static int
456 objfs_data_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
457 	caller_context_t *ct)
458 {
459 	struct module *mp;
460 	timestruc_t now;
461 
462 	if ((mp = objfs_data_lock(vp)) == NULL)
463 		return (EIO);
464 
465 	vap->va_type = VREG;
466 	vap->va_mode = S_IRUSR | S_IRGRP | S_IROTH;
467 	vap->va_nodeid = gfs_file_inode(vp);
468 	vap->va_nlink = 1;
469 	vap->va_size = data_size(mp);
470 	gethrestime(&now);
471 	vap->va_atime = vap->va_ctime = vap->va_mtime = now;
472 
473 	(void) objfs_common_getattr(vp, vap);
474 
475 	objfs_data_unlock(vp);
476 
477 	return (0);
478 }
479 
480 /* ARGSUSED */
481 static int
482 objfs_data_access(vnode_t *vp, int mode, int flags, cred_t *cr,
483 	caller_context_t *ct)
484 {
485 	if (mode & (VWRITE|VEXEC))
486 		return (EACCES);
487 
488 	return (0);
489 }
490 
491 /* ARGSUSED */
492 int
493 objfs_data_open(vnode_t **cpp, int flag, cred_t *cr,
494 	caller_context_t *ct)
495 {
496 	if (flag & FWRITE)
497 		return (EINVAL);
498 
499 	return (0);
500 }
501 
502 /*
503  * Iterate over all symbols in the table and output each one individually,
504  * converting st_shndx to SHN_ABS for each symbol.
505  */
506 static int
507 read_symtab(void *addr, size_t size, off_t offset, uio_t *uio)
508 {
509 #ifdef _LP64
510 	Elf64_Sym sym, *symtab;
511 #else
512 	Elf32_Sym sym, *symtab;
513 #endif
514 	off_t index;
515 	int error;
516 
517 	symtab = addr;
518 
519 	if (offset % sizeof (sym) != 0) {
520 		/*
521 		 * Be careful with the first symbol, as it is not
522 		 * symbol-aligned.
523 		 */
524 		off_t partial = offset % sizeof (sym);
525 
526 		index = offset / sizeof (sym);
527 
528 		sym = symtab[index];
529 		if (sym.st_shndx != SHN_UNDEF)
530 			sym.st_shndx = SHN_ABS;
531 
532 		if ((error = uiomove((char *)&sym + partial,
533 		    sizeof (sym) - partial, UIO_READ, uio)) != 0 ||
534 		    uio->uio_resid <= 0)
535 			return (error);
536 
537 		offset = (index + 1) * sizeof (sym);
538 	}
539 
540 	ASSERT(size % sizeof (sym) == 0);
541 
542 	for (index = offset / sizeof (sym); index < size / sizeof (sym);
543 	    index++) {
544 
545 		sym = symtab[index];
546 		if (sym.st_shndx != SHN_UNDEF)
547 			sym.st_shndx = SHN_ABS;
548 
549 		if ((error = uiomove((char *)&sym, sizeof (sym), UIO_READ,
550 		    uio)) != 0 || uio->uio_resid <= 0)
551 			return (error);
552 	}
553 
554 	return (0);
555 }
556 
557 /* ARGSUSED */
558 static int
559 objfs_data_read(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr,
560 	caller_context_t *ct)
561 {
562 	int error = 0;
563 	objfs_datanode_t *dnode = vp->v_data;
564 	struct module *mp;
565 	off_t off;
566 #ifdef _LP64
567 	Elf64_Shdr shdr;
568 #else
569 	Elf32_Shdr shdr;
570 #endif
571 	int i, j;
572 	section_desc_t *sp;
573 	void *addr;
574 	int transidx[NSECTIONS];
575 
576 	if ((mp = objfs_data_lock(vp)) == NULL)
577 		return (ENOENT);
578 
579 	if (uio->uio_resid <= 0 || uio->uio_offset >= data_size(mp))
580 		goto error;
581 
582 	/*
583 	 * Construct an array to translate from a generic section header index
584 	 * to an index specific for this object.
585 	 */
586 	for (i = 0, j = 0; i < NSECTIONS; i++) {
587 		transidx[i] = j;
588 		if (sect_valid(&data_sections[i], mp))
589 			j++;
590 
591 	}
592 
593 	/*
594 	 * Check to see if we're in the Elf header
595 	 */
596 	if (uio->uio_loffset < SECTION_OFFSET(0)) {
597 #ifdef _LP64
598 		Elf64_Ehdr ehdr;
599 #else
600 		Elf32_Ehdr ehdr;
601 #endif
602 
603 		bzero(&ehdr, sizeof (ehdr));
604 
605 		bcopy(ELFMAG, ehdr.e_ident, SELFMAG);
606 #ifdef _BIG_ENDIAN
607 		ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
608 #else
609 		ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
610 #endif
611 		ehdr.e_ident[EI_VERSION] = EV_CURRENT;
612 
613 #ifdef _LP64
614 		ehdr.e_ident[EI_CLASS] = ELFCLASS64;
615 		ehdr.e_type = ELFCLASS64;
616 		ehdr.e_ehsize = sizeof (Elf64_Ehdr);
617 		ehdr.e_phentsize = sizeof (Elf64_Phdr);
618 		ehdr.e_shentsize = sizeof (Elf64_Shdr);
619 #else
620 		ehdr.e_ident[EI_CLASS] = ELFCLASS32;
621 		ehdr.e_type = ELFCLASS32;
622 		ehdr.e_ehsize = sizeof (Elf32_Ehdr);
623 		ehdr.e_phentsize = sizeof (Elf32_Phdr);
624 		ehdr.e_shentsize = sizeof (Elf32_Shdr);
625 #endif
626 
627 #ifdef __sparc
628 #ifdef __sparcv9
629 		ehdr.e_machine = EM_SPARCV9;
630 #else
631 		ehdr.e_machine = EM_SPARC;
632 #endif
633 #elif defined(__amd64)
634 		ehdr.e_machine = EM_AMD64;
635 #else
636 		ehdr.e_machine = EM_386;
637 #endif
638 
639 		ehdr.e_version = EV_CURRENT;
640 		ehdr.e_type = ET_SUNWPSEUDO;
641 		ehdr.e_shnum = 0;
642 		ehdr.e_shoff = SECTION_OFFSET(0);
643 
644 		for (i = 0; i < NSECTIONS; i++) {
645 			if (strcmp(data_sections[i].sect_name,
646 			    ".shstrtab") == 0)
647 				ehdr.e_shstrndx = transidx[i];
648 
649 			if (sect_valid(&data_sections[i], mp))
650 				ehdr.e_shnum++;
651 		}
652 
653 		if ((error = uiomove((char *)&ehdr + uio->uio_loffset,
654 		    sizeof (ehdr) - uio->uio_loffset, UIO_READ, uio)) != 0 ||
655 		    uio->uio_resid <= 0)
656 			goto error;
657 	}
658 
659 	/*
660 	 * Go through and construct section headers for each section.
661 	 */
662 	j = 0;
663 	for (i = 0; i < NSECTIONS; i++) {
664 		sp = &data_sections[i];
665 
666 		if (!sect_valid(sp, mp))
667 			continue;
668 
669 		if (uio->uio_loffset < SECTION_OFFSET(j+1)) {
670 			shdr.sh_link = transidx[sp->sect_link];
671 			shdr.sh_entsize = sp->sect_entsize;
672 			shdr.sh_info = 0;
673 			shdr.sh_name = sp->sect_str;
674 			shdr.sh_type = sp->sect_type;
675 			shdr.sh_flags = sp->sect_flags;
676 			shdr.sh_addr = sect_addr(sp, mp);
677 			shdr.sh_offset = data_offset(sp, mp);
678 			shdr.sh_size = sect_size(sp, mp);
679 			shdr.sh_addralign = sp->sect_align;
680 
681 			off = uio->uio_loffset - SECTION_OFFSET(j);
682 			if ((error = uiomove((char *)&shdr + off,
683 			    sizeof (shdr) - off, UIO_READ, uio)) != 0 ||
684 			    uio->uio_resid <= 0)
685 				goto error;
686 		}
687 
688 		j++;
689 	}
690 
691 	/*
692 	 * Output the data for each section
693 	 */
694 	for (i = 0; i < NSECTIONS; i++) {
695 		size_t nextoff;
696 		sp = &data_sections[i];
697 		nextoff = next_offset(i, mp);
698 		if (sect_valid(sp, mp) && sp->sect_type != SHT_NOBITS &&
699 		    uio->uio_loffset < nextoff) {
700 
701 			if (sp->sect_id == SECT_TYPE_INFO)
702 				addr = &dnode->objfs_data_info;
703 			else
704 				addr = (void *)sect_addr(sp, mp);
705 			off = uio->uio_loffset - data_offset(sp, mp);
706 
707 			/*
708 			 * The symtab requires special processing to convert
709 			 * the st_shndx field to SHN_ABS.  Otherwise, simply
710 			 * copy the data in bulk.
711 			 */
712 			if (sp->sect_id == SECT_TYPE_SYMTAB)
713 				error = read_symtab(addr, sect_size(sp, mp),
714 				    off, uio);
715 			else
716 				error = uiomove((char *)addr + off,
717 				    sect_size(sp, mp) - off, UIO_READ, uio);
718 
719 			if (error != 0 || uio->uio_resid <= 0)
720 				goto error;
721 
722 			/*
723 			 * If the next section needs to be aligned, pad out with
724 			 * zeroes.
725 			 */
726 			if (uio->uio_loffset < nextoff) {
727 				uint64_t padding = 0;
728 
729 				ASSERT(nextoff - uio->uio_loffset <
730 				    sizeof (uint64_t));
731 
732 				if ((error = uiomove(&padding,
733 				    nextoff - uio->uio_loffset, UIO_READ,
734 				    uio)) != 0 || uio->uio_resid <= 0)
735 					goto error;
736 
737 			}
738 		}
739 	}
740 
741 error:
742 	objfs_data_unlock(vp);
743 
744 	return (error);
745 }
746 
747 /* ARGSUSED */
748 static int
749 objfs_data_seek(vnode_t *vp, offset_t off, offset_t *offp,
750 	caller_context_t *ct)
751 {
752 	return (0);
753 }
754 
755 const fs_operation_def_t objfs_tops_data[] = {
756 	{ VOPNAME_OPEN,		{ .vop_open = objfs_data_open } },
757 	{ VOPNAME_CLOSE,	{ .vop_close = objfs_common_close } },
758 	{ VOPNAME_IOCTL,	{ .error = fs_inval } },
759 	{ VOPNAME_GETATTR,	{ .vop_getattr = objfs_data_getattr } },
760 	{ VOPNAME_ACCESS,	{ .vop_access = objfs_data_access } },
761 	{ VOPNAME_INACTIVE,	{ .vop_inactive = gfs_vop_inactive } },
762 	{ VOPNAME_READ,		{ .vop_read = objfs_data_read } },
763 	{ VOPNAME_SEEK,		{ .vop_seek = objfs_data_seek } },
764 	{ VOPNAME_MAP,		{ .vop_map = gfs_vop_map } },
765 	{ NULL }
766 };
767