2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * This module implements variable storage and management for variant
37 * symlinks. These variables may also be used for general purposes.
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/ucred.h>
44 #include <sys/resourcevar.h>
48 #include <sys/queue.h>
49 #include <sys/sysctl.h>
50 #include <sys/malloc.h>
51 #include <sys/varsym.h>
52 #include <sys/sysmsg.h>
54 MALLOC_DEFINE(M_VARSYM, "varsym", "variable sets for variant symlinks");
56 static struct varsymset varsymset_sys;
59 * Initialize the variant symlink subsystem
62 varsym_sysinit(void *dummy)
64 varsymset_init(&varsymset_sys, NULL);
66 SYSINIT(announce, SI_BOOT2_MACHDEP, SI_ORDER_FIRST, varsym_sysinit, NULL);
69 * varsymreplace() - called from namei
71 * Do variant symlink variable substitution
74 varsymreplace(char *cp, int linklen, int maxlen)
84 if (cp[0] == '$' && cp[1] == '{') {
85 for (i = 2; i < linklen; ++i) {
90 (var = varsymfind(VARSYM_ALL_MASK, cp + 2, i - 2)) != NULL
92 xlen = i + 1; /* bytes to strike */
93 nlen = strlen(var->vs_data); /* bytes to add */
94 if (linklen + nlen - xlen >= maxlen) {
98 KKASSERT(linklen >= xlen);
100 bcopy(cp + xlen, cp + nlen, linklen - xlen);
101 bcopy(var->vs_data, cp, nlen);
102 linklen += nlen - xlen; /* new relative length */
103 rlen += nlen - xlen; /* returned total length */
104 cp += nlen; /* adjust past replacement */
105 linklen -= nlen; /* adjust past replacement */
106 maxlen -= nlen; /* adjust past replacement */
109 * It's ok if i points to the '}', it will simply be
110 * skipped. i could also have hit linklen.
126 * varsym_set() system call
128 * (int level, const char *name, const char *data)
131 sys_varsym_set(struct sysmsg *sysmsg, const struct varsym_set_args *uap)
133 char name[MAXVARSYM_NAME];
138 int level = uap->level;
143 if ((error = copyinstr(uap->name, name, sizeof(name), NULL)) != 0)
145 buf = kmalloc(MAXVARSYM_DATA, M_TEMP, M_WAITOK);
147 (error = copyinstr(uap->data, buf, MAXVARSYM_DATA, NULL)) != 0)
154 if (lp != NULL && td->td_ucred->cr_prison != NULL)
155 level = VARSYM_PRISON;
159 (error = caps_priv_check_td(td, SYSCAP_NOVARSYM_SYS)) != 0)
165 /* XXX check jail / implement per-jail user */
169 (void)varsymmake(level, name, NULL);
170 error = varsymmake(level, name, buf);
172 error = varsymmake(level, name, NULL);
183 * varsym_get() system call
185 * (int mask, const char *wild, char *buf, int bufsize)
190 sys_varsym_get(struct sysmsg *sysmsg, const struct varsym_get_args *uap)
192 char wild[MAXVARSYM_NAME];
197 if ((error = copyinstr(uap->wild, wild, sizeof(wild), NULL)) != 0)
199 sym = varsymfind(uap->mask, wild, strlen(wild));
204 dlen = strlen(sym->vs_data);
205 if (dlen < uap->bufsize) {
206 error = copyout(sym->vs_data, uap->buf, dlen + 1);
207 } else if (uap->bufsize) {
208 copyout("", uap->buf, 1);
211 sysmsg->sysmsg_result = 0;
219 * varsym_list() system call
221 * (int level, char *buf, int maxsize, int *marker)
226 sys_varsym_list(struct sysmsg *sysmsg, const struct varsym_list_args *uap)
228 struct varsymset *vss;
229 struct varsyment *ve;
240 * Get the marker from userspace.
242 if ((error = copyin(uap->marker, &marker, sizeof(marker))) != 0)
246 * Figure out the varsym set.
250 p = lp ? lp->lwp_proc : NULL;
254 switch (uap->level) {
257 vss = &p->p_varsymset;
261 vss = &td->td_ucred->cr_uidinfo->ui_varsymset;
264 vss = &varsymset_sys;
267 if (lp && td->td_ucred->cr_prison)
268 vss = &td->td_ucred->cr_prison->pr_varsymset;
277 * Loop through the variables and dump them to uap->buf
283 lockmgr(&vss->vx_lock, LK_SHARED);
284 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
285 varsym_t sym = ve->ve_sym;
286 int namelen = strlen(sym->vs_name);
287 int datalen = strlen(sym->vs_data);
288 int totlen = namelen + datalen + 2;
291 * Skip to our index point
299 * Stop if there is insufficient space in the user buffer.
300 * If we haven't stored anything yet return EOVERFLOW.
301 * Note that the marker index (i) does not change.
303 if (bytes + totlen > uap->maxsize) {
310 error = copyout(sym->vs_name, uap->buf + bytes, namelen + 1);
312 bytes += namelen + 1;
313 error = copyout(sym->vs_data, uap->buf + bytes, datalen + 1);
315 bytes += datalen + 1;
317 bytes -= namelen + 1; /* revert if error */
325 lockmgr(&vss->vx_lock, LK_RELEASE);
328 * Save the marker back. If no error occured and earlyterm is clear
329 * the marker is set to -1 indicating that the variable list has been
330 * exhausted. If no error occured the number of bytes loaded into
331 * the buffer will be returned, otherwise the syscall code returns -1.
333 if (error == 0 && earlyterm == 0)
338 error = copyout(&marker, uap->marker, sizeof(marker));
339 sysmsg->sysmsg_result = bytes;
345 * Lookup a variant symlink. XXX use a hash table.
349 varsymlookup(struct varsymset *vss, const char *name, int namelen)
351 struct varsyment *ve;
353 KKASSERT(lockstatus(&vss->vx_lock, curthread) != 0);
354 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
355 varsym_t var = ve->ve_sym;
356 if (var->vs_namelen == namelen &&
357 bcmp(name, var->vs_name, namelen) == 0
367 vsslock(struct varsymset **vss, struct varsymset *n)
370 lockmgr(&(*vss)->vx_lock, LK_RELEASE);
372 lockmgr(&n->vx_lock, LK_SHARED);
377 varsymfind(int mask, const char *name, int namelen)
379 struct varsyment *ve = NULL;
380 struct varsymset *vss = NULL;
388 p = lp ? lp->lwp_proc : NULL;
390 if ((mask & (VARSYM_PROC_MASK|VARSYM_USER_MASK)) && lp != NULL) {
391 if (mask & VARSYM_PROC_MASK) {
392 vsslock(&vss, &p->p_varsymset);
393 ve = varsymlookup(vss, name, namelen);
395 if (ve == NULL && (mask & VARSYM_USER_MASK)) {
396 vsslock(&vss, &td->td_ucred->cr_uidinfo->ui_varsymset);
397 ve = varsymlookup(vss, name, namelen);
400 if (ve == NULL && (mask & VARSYM_SYS_MASK)) {
401 if (lp != NULL && td->td_ucred->cr_prison) {
402 vsslock(&vss, &td->td_ucred->cr_prison->pr_varsymset);
403 ve = varsymlookup(vss, name, namelen);
405 vsslock(&vss, &varsymset_sys);
406 ve = varsymlookup(vss, name, namelen);
411 atomic_add_int(&sym->vs_refs, 1);
416 lockmgr(&vss->vx_lock, LK_RELEASE);
421 varsymmake(int level, const char *name, const char *data)
423 struct varsymset *vss = NULL;
424 struct varsyment *ve;
429 int namelen = strlen(name);
435 p = lp ? lp->lwp_proc : NULL;
440 vss = &p->p_varsymset;
444 vss = &td->td_ucred->cr_uidinfo->ui_varsymset;
447 vss = &varsymset_sys;
450 if (lp && td->td_ucred->cr_prison)
451 vss = &td->td_ucred->cr_prison->pr_varsymset;
457 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
458 if (data && vss->vx_setsize >= MAXVARSYM_SET) {
461 datalen = strlen(data);
462 ve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
463 sym = kmalloc(sizeof(struct varsym) + namelen + datalen + 2, M_VARSYM, M_WAITOK);
466 sym->vs_namelen = namelen;
467 sym->vs_name = (char *)(sym + 1);
468 sym->vs_data = sym->vs_name + namelen + 1;
469 strcpy(sym->vs_name, name);
470 strcpy(sym->vs_data, data);
471 TAILQ_INSERT_TAIL(&vss->vx_queue, ve, ve_entry);
472 vss->vx_setsize += sizeof(struct varsyment) + sizeof(struct varsym) + namelen + datalen + 8;
475 if ((ve = varsymlookup(vss, name, namelen)) != NULL) {
476 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
477 vss->vx_setsize -= sizeof(struct varsyment) + sizeof(struct varsym) + namelen + strlen(ve->ve_sym->vs_data) + 8;
478 varsymdrop(ve->ve_sym);
485 lockmgr(&vss->vx_lock, LK_RELEASE);
490 varsymdrop(varsym_t sym)
492 KKASSERT(sym->vs_refs > 0);
493 if (atomic_fetchadd_int(&sym->vs_refs, -1) == 1) {
494 kfree(sym, M_VARSYM);
499 * Insert a duplicate of ve in vss. Does not do any locking,
500 * so it is the callers responsibility to make sure nobody
501 * else can mess with the TAILQ in vss at the same time.
504 varsymdup(struct varsymset *vss, struct varsyment *ve)
506 struct varsyment *nve;
508 nve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
509 nve->ve_sym = ve->ve_sym;
510 ++nve->ve_sym->vs_refs; /* can't be reached, no need for atomic add */
512 * We're only called through varsymset_init() so vss is not yet reachable,
515 TAILQ_INSERT_TAIL(&vss->vx_queue, nve, ve_entry);
519 varsymset_init(struct varsymset *vss, struct varsymset *copy)
521 struct varsyment *ve;
523 TAILQ_INIT(&vss->vx_queue);
524 lockinit(&vss->vx_lock, "vx", 0, 0);
526 TAILQ_FOREACH(ve, ©->vx_queue, ve_entry) {
529 vss->vx_setsize = copy->vx_setsize;
534 varsymset_clean(struct varsymset *vss)
536 struct varsyment *ve;
538 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
539 while ((ve = TAILQ_FIRST(&vss->vx_queue)) != NULL) {
540 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
541 varsymdrop(ve->ve_sym);
545 lockmgr(&vss->vx_lock, LK_RELEASE);