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null.c revision 1.2 
      1 /*	$NetBSD: null.c,v 1.2 2007/01/11 14:59:35 pooka Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2007  Antti Kantee.  All Rights Reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. The name of the company nor the name of the author may be used to
     15  *    endorse or promote products derived from this software without specific
     16  *    prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     19  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     21  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     24  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 #include <sys/cdefs.h>
     32 #if !defined(lint)
     33 __RCSID("$NetBSD: null.c,v 1.2 2007/01/11 14:59:35 pooka Exp $");
     34 #endif /* !lint */
     35 
     36 /*
     37  * A "nullfs" using puffs, i.e. maps one location in the hierarchy
     38  * to another using standard system calls.
     39  */
     40 
     41 #include <sys/types.h>
     42 #include <sys/time.h>
     43 
     44 #include <assert.h>
     45 #include <dirent.h>
     46 #include <errno.h>
     47 #include <fcntl.h>
     48 #include <puffs.h>
     49 #include <stdio.h>
     50 #include <unistd.h>
     51 
     52 PUFFSOP_PROTOS(puffs_null)
     53 
     54 static void *
     55 pathcmp(struct puffs_node *pn, void *arg)
     56 {
     57 
     58 	if (strcmp(arg, pn->pn_path) == 0)
     59 		return pn;
     60 	return NULL;
     61 }
     62 
     63 /*
     64  * set attributes to what is specified.  XXX: no rollback in case of failure
     65  */
     66 static int
     67 processvattr(const char *path, const struct vattr *va, int regular)
     68 {
     69 	struct timeval tv[2];
     70 
     71 	/* XXX: -1 == PUFFS_VNOVAL, but shouldn't trust that */
     72 	if (va->va_uid != (unsigned)-1 || va->va_gid != (unsigned)-1)
     73 		if (lchown(path, va->va_uid, va->va_gid) == -1)
     74 			return errno;
     75 
     76 	if (va->va_mode != (unsigned)PUFFS_VNOVAL)
     77 		if (lchmod(path, va->va_mode) == -1)
     78 			return errno;
     79 
     80 	/* sloppy */
     81 	if (va->va_atime.tv_sec != (unsigned)PUFFS_VNOVAL
     82 	    || va->va_mtime.tv_sec != (unsigned)PUFFS_VNOVAL) {
     83 		TIMESPEC_TO_TIMEVAL(&tv[0], &va->va_atime);
     84 		TIMESPEC_TO_TIMEVAL(&tv[1], &va->va_mtime);
     85 
     86 		if (lutimes(path, tv) == -1)
     87 			return errno;
     88 	}
     89 
     90 	if (regular && va->va_size != (u_quad_t)PUFFS_VNOVAL)
     91 		if (truncate(path, (off_t)va->va_size) == -1)
     92 			return errno;
     93 
     94 	return 0;
     95 }
     96 
     97 /*ARGSUSED*/
     98 int
     99 puffs_null_fs_statvfs(struct puffs_cc *pcc, struct statvfs *svfsb, pid_t pid)
    100 {
    101 	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
    102 
    103 	if (statvfs(pu->pu_pn_root->pn_path, svfsb) == -1)
    104 		return errno;
    105 
    106 	return 0;
    107 }
    108 
    109 /*
    110  * Wow, this kinda looks like a real lookup since it bounces all
    111  * over the place
    112  */
    113 int
    114 puffs_null_node_lookup(struct puffs_cc *pcc, void *opc, void **newnode,
    115 	enum vtype *newtype, voff_t *newsize, dev_t *newrdev,
    116 	const struct puffs_cn *pcn)
    117 {
    118 	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
    119 	struct puffs_node *pn = opc, *pn_res;
    120 	struct dirent entry, *result;
    121 	char dpath[MAXPATHLEN+1];
    122 	char *npath;
    123 	struct stat sb;
    124 	DIR *dp;
    125 	int rv;
    126 
    127 	assert(pn->pn_va.va_type == VDIR);
    128 
    129 	if (pcn->pcn_flags & PUFFS_ISDOTDOT) {
    130 		char *p;
    131 		strcpy(dpath, pn->pn_path);
    132 		p = strrchr(dpath, '/');
    133 		assert(p != NULL);
    134 		*p = '\0';
    135 
    136 		pn_res = puffs_pn_nodewalk(pu, pathcmp, dpath);
    137 		if (pn_res)
    138 			goto success;
    139 		npath = dpath;
    140 		goto getnew;
    141 	}
    142 
    143 	dp = opendir(pn->pn_path);
    144 	if (dp == NULL)
    145 		return errno;
    146 
    147 	/* more readable than for(), IMHO */
    148 	rv = readdir_r(dp, &entry, &result);
    149 	while (rv == 0 && result) {
    150 		if (strcmp(result->d_name, pcn->pcn_name) == 0)
    151 			break;
    152 		rv = readdir_r(dp, &entry, &result);
    153 	}
    154 	closedir(dp);
    155 
    156 	if (rv)
    157 		return rv;
    158 	if (!result)
    159 		return ENOENT;
    160 
    161 	pn_res = puffs_pn_nodewalk(pu, pathcmp, pcn->pcn_fullpath);
    162 	if (pn_res)
    163 		goto success;
    164 	npath = pcn->pcn_fullpath;
    165 
    166  getnew:
    167 	rv = lstat(npath, &sb);
    168 	if (rv)
    169 		return rv;
    170 	pn_res = puffs_pn_new(pu, NULL);
    171 	if (pn_res == NULL)
    172 		return ENOMEM;
    173 	puffs_stat2vattr(&pn_res->pn_va, &sb);
    174 
    175  success:
    176 	*newnode = pn_res;
    177 	*newtype = pn_res->pn_va.va_type;
    178 	*newsize = pn_res->pn_va.va_size;
    179 	*newrdev = pn_res->pn_va.va_rdev;
    180 
    181 	return 0;
    182 }
    183 
    184 /*ARGSUSED*/
    185 int
    186 puffs_null_node_create(struct puffs_cc *pcc, void *opc, void **newnode,
    187 	const struct puffs_cn *pcn, const struct vattr *va)
    188 {
    189 	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
    190 	struct puffs_node *pn;
    191 	int fd, rv;
    192 
    193 	fd = open(pcn->pcn_fullpath, O_RDWR | O_CREAT | O_TRUNC);
    194 	if (fd == -1)
    195 		return errno;
    196 	close(fd);
    197 	if ((rv = processvattr(pcn->pcn_fullpath, va, 1)) != 0) {
    198 		unlink(pcn->pcn_fullpath);
    199 		return rv;
    200 	}
    201 
    202 	pn = puffs_pn_new(pu, NULL);
    203 	if (!pn) {
    204 		unlink(pcn->pcn_fullpath);
    205 		return ENOMEM;
    206 	}
    207 	puffs_setvattr(&pn->pn_va, va);
    208 
    209 	*newnode = pn;
    210 	return 0;
    211 }
    212 
    213 /*ARGSUSED*/
    214 int
    215 puffs_null_node_mknod(struct puffs_cc *pcc, void *opc, void **newnode,
    216 	const struct puffs_cn *pcn, const struct vattr *va)
    217 {
    218 	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
    219 	struct puffs_node *pn;
    220 	int rv;
    221 
    222 	if (mknod(pcn->pcn_fullpath, va->va_mode, va->va_rdev) == -1)
    223 		return errno;
    224 
    225 	if ((rv = processvattr(pcn->pcn_fullpath, va, 0)) != 0) {
    226 		unlink(pcn->pcn_fullpath);
    227 		return rv;
    228 	}
    229 
    230 	pn = puffs_pn_new(pu, NULL);
    231 	if (!pn) {
    232 		unlink(pcn->pcn_fullpath);
    233 		return ENOMEM;
    234 	}
    235 	puffs_setvattr(&pn->pn_va, va);
    236 
    237 	*newnode = pn;
    238 	return 0;
    239 }
    240 
    241 /*ARGSUSED*/
    242 int
    243 puffs_null_node_getattr(struct puffs_cc *pcc, void *opc, struct vattr *va,
    244 	const struct puffs_cred *pcred, pid_t pid)
    245 {
    246 	struct puffs_node *pn = opc;
    247 	struct stat sb;
    248 
    249 	if (lstat(pn->pn_path, &sb) == -1)
    250 		return errno;
    251 	puffs_stat2vattr(va, &sb);
    252 
    253 	return 0;
    254 }
    255 
    256 /*ARGSUSED*/
    257 int
    258 puffs_null_node_setattr(struct puffs_cc *pcc, void *opc,
    259 	const struct vattr *va, const struct puffs_cred *pcred, pid_t pid)
    260 {
    261 	struct puffs_node *pn = opc;
    262 	int rv;
    263 
    264 	rv = processvattr(pn->pn_path, va, pn->pn_va.va_type == VREG);
    265 	if (rv)
    266 		return rv;
    267 
    268 	puffs_setvattr(&pn->pn_va, va);
    269 
    270 	return 0;
    271 }
    272 
    273 /*ARGSUSED*/
    274 int
    275 puffs_null_node_remove(struct puffs_cc *pcc, void *opc, void *targ,
    276 	const struct puffs_cn *pcn)
    277 {
    278 	struct puffs_node *pn_targ = targ;
    279 
    280 	if (unlink(pn_targ->pn_path) == -1)
    281 		return errno;
    282 
    283 	return 0;
    284 }
    285 
    286 /*ARGSUSED*/
    287 int
    288 puffs_null_node_link(struct puffs_cc *pcc, void *opc, void *targ,
    289 	const struct puffs_cn *pcn)
    290 {
    291 	struct puffs_node *pn_targ = targ;
    292 
    293 	if (link(pn_targ->pn_path, pcn->pcn_fullpath) == -1)
    294 		return errno;
    295 
    296 	return 0;
    297 }
    298 
    299 /*ARGSUSED*/
    300 int
    301 puffs_null_node_rename(struct puffs_cc *pcc, void *opc, void *src,
    302 	const struct puffs_cn *pcn_src, void *targ_dir, void *targ,
    303 	const struct puffs_cn *pcn_targ)
    304 {
    305 
    306 	if (rename(pcn_src->pcn_fullpath, pcn_targ->pcn_fullpath) == -1)
    307 		return errno;
    308 
    309 	return 0;
    310 }
    311 
    312 /*ARGSUSED*/
    313 int
    314 puffs_null_node_mkdir(struct puffs_cc *pcc, void *opc, void **newnode,
    315 	const struct puffs_cn *pcn, const struct vattr *va)
    316 {
    317 	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
    318 	struct puffs_node *pn;
    319 	int rv;
    320 
    321 	if (mkdir(pcn->pcn_fullpath, va->va_mode) == -1)
    322 		return errno;
    323 
    324 	if ((rv = processvattr(pcn->pcn_fullpath, va, 0)) != 0) {
    325 		unlink(pcn->pcn_fullpath);
    326 		return rv;
    327 	}
    328 
    329 	pn = puffs_pn_new(pu, NULL);
    330 	if (pn == NULL) {
    331 		rmdir(pcn->pcn_fullpath);
    332 		return ENOMEM;
    333 	}
    334 	puffs_setvattr(&pn->pn_va, va);
    335 
    336 	*newnode = pn;
    337 	return 0;
    338 }
    339 
    340 /*ARGSUSED*/
    341 int
    342 puffs_null_node_rmdir(struct puffs_cc *pcc, void *opc, void *targ,
    343 	const struct puffs_cn *pcn)
    344 {
    345 	struct puffs_node *pn_targ = targ;
    346 
    347 	if (rmdir(pn_targ->pn_path) == -1)
    348 		return errno;
    349 
    350 	return 0;
    351 }
    352 
    353 /*ARGSUSED*/
    354 int
    355 puffs_null_node_symlink(struct puffs_cc *pcc, void *opc, void **newnode,
    356 	const struct puffs_cn *pcn, const struct vattr *va,
    357 	const char *linkname)
    358 {
    359 	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
    360 	struct puffs_node *pn;
    361 	int rv;
    362 
    363 	if (symlink(linkname, pcn->pcn_fullpath) == -1)
    364 		return errno;
    365 
    366 	if ((rv = processvattr(pcn->pcn_fullpath, va, 0)) != 0) {
    367 		unlink(pcn->pcn_fullpath);
    368 		return rv;
    369 	}
    370 
    371 	pn = puffs_pn_new(pu, NULL);
    372 	if (pn == NULL) {
    373 		rmdir(pcn->pcn_fullpath);
    374 		return ENOMEM;
    375 	}
    376 	puffs_setvattr(&pn->pn_va, va);
    377 
    378 	*newnode = pn;
    379 	return 0;
    380 }
    381 
    382 /*ARGSUSED*/
    383 int
    384 puffs_null_node_readlink(struct puffs_cc *pcc, void *opc,
    385 	const struct puffs_cred *pcred, char *linkname, size_t *linklen)
    386 {
    387 	struct puffs_node *pn = opc;
    388 	ssize_t rv;
    389 
    390 	rv = readlink(pn->pn_path, linkname, *linklen);
    391 	if (rv == -1)
    392 		return errno;
    393 
    394 	*linklen -= rv;
    395 	return 0;
    396 }
    397 
    398 /*ARGSUSED*/
    399 int
    400 puffs_null_node_readdir(struct puffs_cc *pcc, void *opc, struct dirent *de,
    401 	const struct puffs_cred *pcred, off_t *off, size_t *reslen)
    402 {
    403 	struct puffs_node *pn = opc;
    404 	struct dirent entry, *result;
    405 	DIR *dp;
    406 	off_t i;
    407 	int rv;
    408 
    409 	dp = opendir(pn->pn_path);
    410 	if (dp == NULL)
    411 		return errno;
    412 
    413 	rv = 0;
    414 	i = *off;
    415 
    416 	/*
    417 	 * XXX: need to do trickery here, telldir/seekdir would be nice, but
    418 	 * then we'd need to keep state, which I'm too lazy to keep
    419 	 */
    420 	while (i--) {
    421 		rv = readdir_r(dp, &entry, &result);
    422 		if (rv || !result)
    423 			goto out;
    424 	}
    425 
    426 	for (;;) {
    427 		rv = readdir_r(dp, &entry, &result);
    428 		if (rv != 0)
    429 			goto out;
    430 
    431 		if (!result)
    432 			goto out;
    433 
    434 		if (_DIRENT_SIZE(result) > *reslen)
    435 			goto out;
    436 
    437 		*de = *result;
    438 		*reslen -= _DIRENT_SIZE(result);
    439 		de = _DIRENT_NEXT(de);
    440 
    441 		(*off)++;
    442 	}
    443 
    444  out:
    445 	closedir(dp);
    446 	return 0;
    447 }
    448 
    449 /*ARGSUSED*/
    450 int
    451 puffs_null_node_read(struct puffs_cc *pcc, void *opc, uint8_t *buf,
    452 	off_t offset, size_t *buflen, const struct puffs_cred *pcred,
    453 	int ioflag)
    454 {
    455 	struct puffs_node *pn = opc;
    456 	ssize_t n;
    457 	off_t off;
    458 	int fd, rv;
    459 
    460 	rv = 0;
    461 	fd = open(pn->pn_path, O_RDONLY);
    462 	if (fd == -1)
    463 		return errno;
    464 	off = lseek(fd, offset, SEEK_SET);
    465 	if (off == -1) {
    466 		rv = errno;
    467 		goto out;
    468 	}
    469 
    470 	n = read(fd, buf, *buflen);
    471 	if (n == -1)
    472 		rv = errno;
    473 	else
    474 		*buflen -= n;
    475 
    476  out:
    477 	close(fd);
    478 	return rv;
    479 }
    480 
    481 /*ARGSUSED*/
    482 int
    483 puffs_null_node_write(struct puffs_cc *pcc, void *opc, uint8_t *buf,
    484 	off_t offset, size_t *buflen, const struct puffs_cred *pcred,
    485 	int ioflag)
    486 {
    487 	struct puffs_node *pn = opc;
    488 	ssize_t n;
    489 	off_t off;
    490 	int fd, rv;
    491 
    492 	rv = 0;
    493 	fd = open(pn->pn_path, O_WRONLY);
    494 	if (fd == -1) {
    495 		/*
    496 		 * XXXkludge: try again with better perms.  need to fix
    497 		 * this better somehow
    498 		 */
    499 		if (errno == EACCES) {
    500 			struct stat sb;
    501 			mode_t origmode;
    502 			int sverr = 0;
    503 
    504 			if (stat(pn->pn_path, &sb) == -1)
    505 				return errno;
    506 			origmode = sb.st_mode & ALLPERMS;
    507 
    508 			if (chmod(pn->pn_path, 0200) == -1)
    509 				return errno;
    510 
    511 			fd = open(pn->pn_path, O_WRONLY);
    512 			if (fd == -1)
    513 				sverr = errno;
    514 
    515 			chmod(pn->pn_path, origmode);
    516 			if (sverr)
    517 				return sverr;
    518 		} else
    519 			return errno;
    520 	}
    521 	off = lseek(fd, offset, SEEK_SET);
    522 	if (off == -1) {
    523 		rv = errno;
    524 		goto out;
    525 	}
    526 
    527 	n = write(fd, buf, *buflen);
    528 	if (n == -1)
    529 		rv = errno;
    530 	else
    531 		*buflen -= n;
    532 
    533  out:
    534 	close(fd);
    535 	return rv;
    536 }
    537