xref: /titanic_44/usr/src/uts/common/fs/objfs/objfs_data.c (revision 672986541be54a7a471bb088e60780c37e371d7e)
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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <fs/fs_subr.h>
29 
30 #include <sys/elf.h>
31 #include <sys/errno.h>
32 #include <sys/file.h>
33 #include <sys/kmem.h>
34 #include <sys/kobj.h>
35 #include <sys/objfs.h>
36 #include <sys/objfs_impl.h>
37 #include <sys/stat.h>
38 #include <sys/systm.h>
39 #include <sys/sysmacros.h>
40 #include <sys/vfs_opreg.h>
41 
42 /*
43  * /system/object/<obj>/object
44  *
45  * This is an ELF file that contains information about data stored in the
46  * kernel.  We use a special ELF file type, ET_SUNWPSEUDO, so that we can
47  * control which fields and sections have meaning.  The file contains the
48  * following sections:
49  *
50  * 	.shstrtab	Section header string table
51  * 	.SUNW_ctf	CTF data
52  * 	.symtab		Symbol table
53  * 	.strtab		String table
54  * 	.text		Text
55  * 	.data		Data
56  * 	.bss		BSS
57  * 	.filename	Filename of module
58  * 	.info		Private module info structure
59  *
60  * The .text, .data, and .bss sections are all marked SHT_NOBITS, and the data
61  * is not actually exported in the file for security reasons.  The section
62  * headers do contain the address and size of the sections, which is needed by
63  * DTrace.  The CTF data, symbol table, and string table are present only if
64  * they exist in the kernel.
65  */
66 
67 typedef enum {
68 	SECT_TYPE_DATA,
69 	SECT_TYPE_SHSTRTAB,
70 	SECT_TYPE_DUMMY,
71 	SECT_TYPE_SYMTAB,
72 	SECT_TYPE_STRTAB,
73 	SECT_TYPE_FILENAME,
74 	SECT_TYPE_INFO
75 } sect_type_t;
76 
77 typedef struct section_desc {
78 	sect_type_t	sect_id;
79 	const char	*sect_name;
80 	uintptr_t	sect_addr;
81 	size_t		sect_size;
82 	int		sect_type;
83 	int		sect_flags;
84 	size_t		sect_str;
85 	int		sect_link;
86 	int		sect_entsize;
87 	int		sect_align;
88 } section_desc_t;
89 
90 /*
91  * For data sections, 'addr' and 'size' refer to offsets within the module
92  * structure where we can find the address and size of the section.
93  */
94 #define	SECT_DATA(name, addr, size, type, flags, align) \
95 	{ SECT_TYPE_DATA, name, offsetof(struct module, addr), \
96 	offsetof(struct module, size), type, flags, 0, 0, 0, align }
97 
98 /*
99  * The dummy section is the initial section of the file.  It is put into this
100  * array only for convenience when reading the file.
101  */
102 #define	SECT_DUMMY	{ SECT_TYPE_DUMMY, "", 0, 0, 0, 0, 0, 0, 0, 0 }
103 
104 /*
105  * The size of the symbol table and string table are not immediately available
106  * as an offset into the module struct, so we have to create individual types
107  * for each.
108  */
109 #ifdef _LP64
110 #define	SECT_SYMTAB(name, type, flags) \
111 	{ SECT_TYPE_SYMTAB, name, offsetof(struct module, symtbl), 0, type, \
112 	flags, 0, 0, sizeof (Elf64_Sym), sizeof (uint64_t) }
113 #else
114 #define	SECT_SYMTAB(name, type, flags) \
115 	{ SECT_TYPE_SYMTAB, name, offsetof(struct module, symtbl), 0, type, \
116 	flags, 0, 0, sizeof (Elf32_Sym), sizeof (uint32_t) }
117 #endif
118 #define	SECT_STRTAB(name, type, flags) \
119 	{ SECT_TYPE_STRTAB, name, offsetof(struct module, strings), 0, type, \
120 	flags, 0, 0, 0, 1 }
121 
122 /*
123  * The .shstrtab section is constructed when the module is first loaded.
124  */
125 #define	SECT_SHSTRTAB(name, type, flags) \
126 	{ SECT_TYPE_SHSTRTAB, name, 0, 0, type, flags, 0, 0, 0, 1 }
127 
128 /*
129  * Generic module information (objfs_info_t)
130  */
131 #define	SECT_INFO	\
132 	{ SECT_TYPE_INFO, ".info", 0, 0, SHT_PROGBITS, 0, 0, 0, 0, \
133 	sizeof (uint32_t) }
134 
135 /*
136  * Filename section.
137  */
138 #define	SECT_FILENAME	\
139 	{ SECT_TYPE_FILENAME, ".filename", 0, 0, SHT_PROGBITS, 0, 0, 0, 0, 1 }
140 
141 static section_desc_t data_sections[] = {
142 	SECT_DUMMY,
143 	SECT_SHSTRTAB(".shstrtab",
144 	    SHT_STRTAB, SHF_STRINGS),
145 	SECT_DATA(".SUNW_ctf", ctfdata, ctfsize,
146 	    SHT_PROGBITS, 0, sizeof (uint64_t)),
147 	SECT_SYMTAB(".symtab", SHT_SYMTAB, 0),
148 	SECT_STRTAB(".strtab", SHT_STRTAB, SHF_STRINGS),
149 	SECT_DATA(".text", text, text_size,
150 	    SHT_NOBITS, SHF_ALLOC | SHF_EXECINSTR, 0),
151 	SECT_DATA(".data", data, data_size,
152 	    SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0),
153 	SECT_DATA(".bss", bss, bss_size,
154 	    SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0),
155 	SECT_INFO,
156 	SECT_FILENAME
157 };
158 
159 #define	NSECTIONS	\
160 	(sizeof (data_sections) / sizeof (section_desc_t))
161 
162 #ifdef _LP64
163 #define	SECTION_OFFSET(section)	\
164 	(sizeof (Elf64_Ehdr) + (section) * sizeof (Elf64_Shdr))
165 #else
166 #define	SECTION_OFFSET(section)	\
167 	(sizeof (Elf32_Ehdr) + (section) * sizeof (Elf32_Shdr))
168 #endif
169 
170 /*
171  * Given a data node, returns the struct module appropriately locked.  If the
172  * object has been unloaded, or re-loaded since the file was first opened, this
173  * function will return NULL.  If successful, the caller must call
174  * objfs_data_unlock().
175  */
176 struct module *
177 objfs_data_lock(vnode_t *vp)
178 {
179 	objfs_datanode_t *dnode = vp->v_data;
180 	objfs_odirnode_t *odir = gfs_file_parent(vp)->v_data;
181 	struct modctl *mp = odir->objfs_odir_modctl;
182 
183 	(void) mod_hold_by_modctl(mp, MOD_WAIT_FOREVER | MOD_LOCK_NOT_HELD);
184 
185 	if (mp->mod_mp == NULL ||
186 	    dnode->objfs_data_gencount < mp->mod_gencount) {
187 		mod_release_mod(mp);
188 		return (NULL);
189 	}
190 
191 	return (mp->mod_mp);
192 }
193 
194 void
195 objfs_data_unlock(vnode_t *vp)
196 {
197 	objfs_odirnode_t *odir = gfs_file_parent(vp)->v_data;
198 
199 	mod_release_mod(odir->objfs_odir_modctl);
200 }
201 
202 
203 /*
204  * Called when the filesystem is first loaded.  Creates and initializes the
205  * section header string table, and fills in the sect_str members of the section
206  * descriptors.  This information could be encoded at compile-time, but this
207  * way keeps the code more maintainable, as we don't have to worry about
208  * duplicating information.
209  */
210 void
211 objfs_data_init(void)
212 {
213 	int i, shstrtab, strtab, symtab;
214 	size_t len = 0;
215 	section_desc_t *sect;
216 	char *strdata;
217 
218 	for (i = 0; i < NSECTIONS; i++) {
219 		sect = &data_sections[i];
220 
221 		ASSERT(sect->sect_align == 0 || ISP2(sect->sect_align));
222 		ASSERT(sect->sect_align <= sizeof (uint64_t));
223 
224 		len += strlen(sect->sect_name) + 1;
225 		if (strcmp(sect->sect_name, ".shstrtab") == 0)
226 			shstrtab = i;
227 		else if (strcmp(sect->sect_name, ".symtab") == 0)
228 			symtab = i;
229 		else if (strcmp(sect->sect_name, ".strtab") == 0)
230 			strtab = i;
231 	}
232 
233 	strdata = kmem_zalloc(len, KM_SLEEP);
234 	sect = &data_sections[shstrtab];
235 	sect->sect_addr = (uintptr_t)strdata;
236 	sect->sect_size = len;
237 
238 	len = 0;
239 	for (i = 0; i < NSECTIONS; i++) {
240 		sect = &data_sections[i];
241 		sect->sect_str = len;
242 		bcopy(sect->sect_name, strdata + len,
243 		    strlen(sect->sect_name) + 1);
244 		len += strlen(sect->sect_name) + 1;
245 
246 		if (strcmp(sect->sect_name, ".SUNW_ctf") == 0)
247 			sect->sect_link = symtab;
248 		else if (strcmp(sect->sect_name, ".symtab") == 0)
249 			sect->sect_link = strtab;
250 	}
251 }
252 
253 /*
254  * Given a section descriptor and module pointer, return the address of the
255  * data.
256  */
257 static uintptr_t
258 sect_addr(section_desc_t *sp, struct module *mp)
259 {
260 	uintptr_t addr;
261 
262 	switch (sp->sect_id) {
263 	case SECT_TYPE_DUMMY:
264 		addr = 0;
265 		break;
266 
267 	case SECT_TYPE_SHSTRTAB:
268 		addr = sp->sect_addr;
269 		break;
270 
271 	case SECT_TYPE_STRTAB:
272 	case SECT_TYPE_SYMTAB:
273 	case SECT_TYPE_DATA:
274 		addr = *((uintptr_t *)((char *)mp + sp->sect_addr));
275 		break;
276 
277 	case SECT_TYPE_FILENAME:
278 		addr = (uintptr_t)mp->filename;
279 		break;
280 
281 	case SECT_TYPE_INFO:
282 		addr = 1;	/* This can be anything nonzero */
283 		break;
284 	}
285 
286 	return (addr);
287 }
288 
289 /*
290  * Given a section descriptor and module pointer, return the size of the data.
291  */
292 static size_t
293 sect_size(section_desc_t *sp, struct module *mp)
294 {
295 	size_t size;
296 
297 	switch (sp->sect_id) {
298 	case SECT_TYPE_DUMMY:
299 		size = 0;
300 		break;
301 
302 	case SECT_TYPE_SHSTRTAB:
303 		size = sp->sect_size;
304 		break;
305 
306 	case SECT_TYPE_DATA:
307 		size = *((size_t *)((char *)mp + sp->sect_size));
308 		break;
309 
310 	case SECT_TYPE_SYMTAB:
311 		size = mp->symhdr->sh_size;
312 		break;
313 
314 	case SECT_TYPE_STRTAB:
315 		size = mp->strhdr->sh_size;
316 		break;
317 
318 	case SECT_TYPE_INFO:
319 		size = sizeof (objfs_info_t);
320 		break;
321 
322 	case SECT_TYPE_FILENAME:
323 		if (mp->filename == NULL)
324 			size = 0;
325 		else
326 			size = strlen(mp->filename) + 1;
327 	}
328 
329 	return (size);
330 }
331 
332 /*
333  * Given a section descriptor and module pointer, return 1 if the section has
334  * valid data and should be included, 0 otherwise.
335  */
336 static int
337 sect_valid(section_desc_t *sp, struct module *mp)
338 {
339 	if (sp->sect_id == SECT_TYPE_DUMMY ||
340 	    sect_addr(sp, mp) != 0)
341 		return (1);
342 
343 	return (0);
344 }
345 
346 /*
347  * Given a section descriptor and module pointer, return the offset into the
348  * file where the data should be placed.
349  */
350 static size_t
351 data_offset(section_desc_t *sp, struct module *mp)
352 {
353 	int i;
354 	size_t len;
355 	section_desc_t *cp;
356 
357 	if (sp != NULL && mp != NULL && !sect_valid(sp, mp))
358 		return (0);
359 
360 #ifdef _LP64
361 	len = sizeof (Elf64_Ehdr);
362 #else
363 	len = sizeof (Elf32_Ehdr);
364 #endif
365 
366 	/*
367 	 * Do a first pass to account for all the section headers.
368 	 */
369 	for (i = 0; i < NSECTIONS; i++) {
370 		if (sect_valid(&data_sections[i], mp)) {
371 #ifdef _LP64
372 			len += sizeof (Elf64_Shdr);
373 #else
374 			len += sizeof (Elf32_Shdr);
375 #endif
376 		}
377 	}
378 
379 	/*
380 	 * Add length of each section until we find the one we're looking for.
381 	 */
382 	for (i = 0; i < NSECTIONS; i++) {
383 		cp = &data_sections[i];
384 
385 		/*
386 		 * Align the section only if it's valid and contains data.  When
387 		 * searching for a specific section, align the section before
388 		 * breaking out of the loop.
389 		 */
390 		if (sect_valid(cp, mp) && cp->sect_type != SHT_NOBITS) {
391 			if (cp->sect_align > 1)
392 				len = P2ROUNDUP(len, cp->sect_align);
393 
394 			if (sp != cp)
395 				len += sect_size(cp, mp);
396 		}
397 
398 		if (sp == cp)
399 			break;
400 	}
401 
402 	return (len);
403 }
404 
405 /*
406  * Given an index into the section table and a module pointer, returns the
407  * data offset of the next section.
408  */
409 static size_t
410 next_offset(int idx, struct module *mp)
411 {
412 	int i;
413 
414 	for (i = idx + 1; i < NSECTIONS; i++) {
415 		if (sect_valid(&data_sections[i], mp))
416 			return (data_offset(&data_sections[i], mp));
417 	}
418 
419 	return (data_offset(NULL, mp));
420 }
421 
422 /*
423  * Given a module pointer, return the total size needed for the file.
424  */
425 static size_t
426 data_size(struct module *mp)
427 {
428 	return (data_offset(NULL, mp));
429 }
430 
431 /*
432  * Returns the size needed for all the headers in the file.
433  */
434 static size_t
435 header_size(void)
436 {
437 	return (data_offset(&data_sections[0], NULL));
438 }
439 
440 /* ARGSUSED */
441 vnode_t *
442 objfs_create_data(vnode_t *pvp)
443 {
444 	objfs_odirnode_t *onode = pvp->v_data;
445 	vnode_t *vp = gfs_file_create(sizeof (objfs_datanode_t), pvp,
446 	    objfs_ops_data);
447 	objfs_datanode_t *dnode = vp->v_data;
448 
449 	dnode->objfs_data_gencount = onode->objfs_odir_modctl->mod_gencount;
450 	dnode->objfs_data_info.objfs_info_primary =
451 	    onode->objfs_odir_modctl->mod_prim;
452 
453 	return (vp);
454 }
455 
456 /* ARGSUSED */
457 static int
458 objfs_data_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr)
459 {
460 	struct module *mp;
461 	timestruc_t now;
462 
463 	if ((mp = objfs_data_lock(vp)) == NULL)
464 		return (EIO);
465 
466 	vap->va_type = VREG;
467 	vap->va_mode = S_IRUSR | S_IRGRP | S_IROTH;
468 	vap->va_nodeid = gfs_file_inode(vp);
469 	vap->va_nlink = 1;
470 	vap->va_size = data_size(mp);
471 	gethrestime(&now);
472 	vap->va_atime = vap->va_ctime = vap->va_mtime = now;
473 
474 	(void) objfs_common_getattr(vp, vap);
475 
476 	objfs_data_unlock(vp);
477 
478 	return (0);
479 }
480 
481 /* ARGSUSED */
482 static int
483 objfs_data_access(vnode_t *vp, int mode, int flags, cred_t *cr)
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 {
495 	if (flag & FWRITE)
496 		return (EINVAL);
497 
498 	return (0);
499 }
500 
501 /*
502  * Iterate over all symbols in the table and output each one individually,
503  * converting st_shndx to SHN_ABS for each symbol.
504  */
505 static int
506 read_symtab(void *addr, size_t size, off_t offset, uio_t *uio)
507 {
508 #ifdef _LP64
509 	Elf64_Sym sym, *symtab;
510 #else
511 	Elf32_Sym sym, *symtab;
512 #endif
513 	off_t index;
514 	int error;
515 
516 	symtab = addr;
517 
518 	if (offset % sizeof (sym) != 0) {
519 		/*
520 		 * Be careful with the first symbol, as it is not
521 		 * symbol-aligned.
522 		 */
523 		off_t partial = offset % sizeof (sym);
524 
525 		index = offset / sizeof (sym);
526 
527 		sym = symtab[index];
528 		if (sym.st_shndx != SHN_UNDEF)
529 			sym.st_shndx = SHN_ABS;
530 
531 		if ((error = uiomove((char *)&sym + partial,
532 		    sizeof (sym) - partial, UIO_READ, uio)) != 0 ||
533 		    uio->uio_resid <= 0)
534 			return (error);
535 
536 		offset = (index + 1) * sizeof (sym);
537 	}
538 
539 	ASSERT(size % sizeof (sym) == 0);
540 
541 	for (index = offset / sizeof (sym); index < size / sizeof (sym);
542 	    index++) {
543 
544 		sym = symtab[index];
545 		if (sym.st_shndx != SHN_UNDEF)
546 			sym.st_shndx = SHN_ABS;
547 
548 		if ((error = uiomove((char *)&sym, sizeof (sym), UIO_READ,
549 		    uio)) != 0 || uio->uio_resid <= 0)
550 			return (error);
551 	}
552 
553 	return (0);
554 }
555 
556 /* ARGSUSED */
557 static int
558 objfs_data_read(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr,
559     caller_context_t *ct)
560 {
561 	int error = 0;
562 	objfs_datanode_t *dnode = vp->v_data;
563 	struct module *mp;
564 	off_t off;
565 #ifdef _LP64
566 	Elf64_Shdr shdr;
567 #else
568 	Elf32_Shdr shdr;
569 #endif
570 	int i, j;
571 	section_desc_t *sp;
572 	void *addr;
573 	int transidx[NSECTIONS];
574 
575 	if ((mp = objfs_data_lock(vp)) == NULL)
576 		return (ENOENT);
577 
578 	if (uio->uio_resid <= 0 || uio->uio_offset >= data_size(mp))
579 		goto error;
580 
581 	/*
582 	 * Construct an array to translate from a generic section header index
583 	 * to an index specific for this object.
584 	 */
585 	for (i = 0, j = 0; i < NSECTIONS; i++) {
586 		transidx[i] = j;
587 		if (sect_valid(&data_sections[i], mp))
588 			j++;
589 
590 	}
591 
592 	/*
593 	 * Check to see if we're in the Elf header
594 	 */
595 	if (uio->uio_loffset < SECTION_OFFSET(0)) {
596 #ifdef _LP64
597 		Elf64_Ehdr ehdr;
598 #else
599 		Elf32_Ehdr ehdr;
600 #endif
601 
602 		bzero(&ehdr, sizeof (ehdr));
603 
604 		bcopy(ELFMAG, ehdr.e_ident, SELFMAG);
605 #ifdef _BIG_ENDIAN
606 		ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
607 #else
608 		ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
609 #endif
610 		ehdr.e_ident[EI_VERSION] = EV_CURRENT;
611 
612 #ifdef _LP64
613 		ehdr.e_ident[EI_CLASS] = ELFCLASS64;
614 		ehdr.e_type = ELFCLASS64;
615 		ehdr.e_ehsize = sizeof (Elf64_Ehdr);
616 		ehdr.e_phentsize = sizeof (Elf64_Phdr);
617 		ehdr.e_shentsize = sizeof (Elf64_Shdr);
618 #else
619 		ehdr.e_ident[EI_CLASS] = ELFCLASS32;
620 		ehdr.e_type = ELFCLASS32;
621 		ehdr.e_ehsize = sizeof (Elf32_Ehdr);
622 		ehdr.e_phentsize = sizeof (Elf32_Phdr);
623 		ehdr.e_shentsize = sizeof (Elf32_Shdr);
624 #endif
625 
626 #ifdef __sparc
627 #ifdef __sparcv9
628 		ehdr.e_machine = EM_SPARCV9;
629 #else
630 		ehdr.e_machine = EM_SPARC;
631 #endif
632 #elif defined(__amd64)
633 		ehdr.e_machine = EM_AMD64;
634 #else
635 		ehdr.e_machine = EM_386;
636 #endif
637 
638 		ehdr.e_version = EV_CURRENT;
639 		ehdr.e_type = ET_SUNWPSEUDO;
640 		ehdr.e_shnum = 0;
641 		ehdr.e_shoff = SECTION_OFFSET(0);
642 
643 		for (i = 0; i < NSECTIONS; i++) {
644 			if (strcmp(data_sections[i].sect_name,
645 			    ".shstrtab") == 0)
646 				ehdr.e_shstrndx = transidx[i];
647 
648 			if (sect_valid(&data_sections[i], mp))
649 				ehdr.e_shnum++;
650 		}
651 
652 		if ((error = uiomove((char *)&ehdr + uio->uio_loffset,
653 		    sizeof (ehdr) - uio->uio_loffset, UIO_READ, uio)) != 0 ||
654 		    uio->uio_resid <= 0)
655 			goto error;
656 	}
657 
658 	/*
659 	 * Go through and construct section headers for each section.
660 	 */
661 	j = 0;
662 	for (i = 0; i < NSECTIONS; i++) {
663 		sp = &data_sections[i];
664 
665 		if (!sect_valid(sp, mp))
666 			continue;
667 
668 		if (uio->uio_loffset < SECTION_OFFSET(j+1)) {
669 			shdr.sh_link = transidx[sp->sect_link];
670 			shdr.sh_entsize = sp->sect_entsize;
671 			shdr.sh_info = 0;
672 			shdr.sh_name = sp->sect_str;
673 			shdr.sh_type = sp->sect_type;
674 			shdr.sh_flags = sp->sect_flags;
675 			shdr.sh_addr = sect_addr(sp, mp);
676 			shdr.sh_offset = data_offset(sp, mp);
677 			shdr.sh_size = sect_size(sp, mp);
678 			shdr.sh_addralign = sp->sect_align;
679 
680 			off = uio->uio_loffset - SECTION_OFFSET(j);
681 			if ((error = uiomove((char *)&shdr + off,
682 			    sizeof (shdr) - off, UIO_READ, uio)) != 0 ||
683 			    uio->uio_resid <= 0)
684 				goto error;
685 		}
686 
687 		j++;
688 	}
689 
690 	/*
691 	 * Output the data for each section
692 	 */
693 	for (i = 0; i < NSECTIONS; i++) {
694 		size_t nextoff;
695 		sp = &data_sections[i];
696 		nextoff = next_offset(i, mp);
697 		if (sect_valid(sp, mp) && sp->sect_type != SHT_NOBITS &&
698 		    uio->uio_loffset < nextoff) {
699 
700 			if (sp->sect_id == SECT_TYPE_INFO)
701 				addr = &dnode->objfs_data_info;
702 			else
703 				addr = (void *)sect_addr(sp, mp);
704 			off = uio->uio_loffset - data_offset(sp, mp);
705 
706 			/*
707 			 * The symtab requires special processing to convert
708 			 * the st_shndx field to SHN_ABS.  Otherwise, simply
709 			 * copy the data in bulk.
710 			 */
711 			if (sp->sect_id == SECT_TYPE_SYMTAB)
712 				error = read_symtab(addr, sect_size(sp, mp),
713 				    off, uio);
714 			else
715 				error = uiomove((char *)addr + off,
716 				    sect_size(sp, mp) - off, UIO_READ, uio);
717 
718 			if (error != 0 || uio->uio_resid <= 0)
719 				goto error;
720 
721 			/*
722 			 * If the next section needs to be aligned, pad out with
723 			 * zeroes.
724 			 */
725 			if (uio->uio_loffset < nextoff) {
726 				uint64_t padding = 0;
727 
728 				ASSERT(nextoff - uio->uio_loffset <
729 				    sizeof (uint64_t));
730 
731 				if ((error = uiomove(&padding,
732 				    nextoff - uio->uio_loffset, UIO_READ,
733 				    uio)) != 0 || uio->uio_resid <= 0)
734 					goto error;
735 
736 			}
737 		}
738 	}
739 
740 error:
741 	objfs_data_unlock(vp);
742 
743 	return (error);
744 }
745 
746 /* ARGSUSED */
747 static int
748 objfs_data_seek(vnode_t *vp, offset_t off, offset_t *offp)
749 {
750 	return (0);
751 }
752 
753 const fs_operation_def_t objfs_tops_data[] = {
754 	{ VOPNAME_OPEN,		{ .vop_open = objfs_data_open } },
755 	{ VOPNAME_CLOSE,	{ .vop_close = objfs_common_close } },
756 	{ VOPNAME_IOCTL,	{ .error = fs_inval } },
757 	{ VOPNAME_GETATTR,	{ .vop_getattr = objfs_data_getattr } },
758 	{ VOPNAME_ACCESS,	{ .vop_access = objfs_data_access } },
759 	{ VOPNAME_INACTIVE,	{ .vop_inactive = gfs_vop_inactive } },
760 	{ VOPNAME_READ,		{ .vop_read = objfs_data_read } },
761 	{ VOPNAME_SEEK,		{ .vop_seek = objfs_data_seek } },
762 	{ VOPNAME_MAP,		{ .vop_map = gfs_vop_map } },
763 	{ NULL }
764 };
765