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/sysproto.h>
54 #include <sys/mplock2.h>
56 MALLOC_DEFINE(M_VARSYM, "varsym", "variable sets for variant symlinks");
58 struct varsymset varsymset_sys;
61 * Initialize the variant symlink subsystem
64 varsym_sysinit(void *dummy)
66 varsymset_init(&varsymset_sys, NULL);
68 SYSINIT(announce, SI_BOOT2_MACHDEP, SI_ORDER_FIRST, varsym_sysinit, NULL);
71 * varsymreplace() - called from namei
73 * Do variant symlink variable substitution
76 varsymreplace(char *cp, int linklen, int maxlen)
86 if (cp[0] == '$' && cp[1] == '{') {
87 for (i = 2; i < linklen; ++i) {
92 (var = varsymfind(VARSYM_ALL_MASK, cp + 2, i - 2)) != NULL
94 xlen = i + 1; /* bytes to strike */
95 nlen = strlen(var->vs_data); /* bytes to add */
96 if (linklen + nlen - xlen >= maxlen) {
100 KKASSERT(linklen >= xlen);
102 bcopy(cp + xlen, cp + nlen, linklen - xlen);
103 bcopy(var->vs_data, cp, nlen);
104 linklen += nlen - xlen; /* new relative length */
105 rlen += nlen - xlen; /* returned total length */
106 cp += nlen; /* adjust past replacement */
107 linklen -= nlen; /* adjust past replacement */
108 maxlen -= nlen; /* adjust past replacement */
111 * It's ok if i points to the '}', it will simply be
112 * skipped. i could also have hit linklen.
128 * varsym_set() system call
130 * (int level, const char *name, const char *data)
135 sys_varsym_set(struct varsym_set_args *uap)
137 char name[MAXVARSYM_NAME];
146 if ((error = copyinstr(uap->name, name, sizeof(name), NULL)) != 0)
148 buf = kmalloc(MAXVARSYM_DATA, M_TEMP, M_WAITOK);
150 (error = copyinstr(uap->data, buf, MAXVARSYM_DATA, NULL)) != 0)
159 if (lp != NULL && td->td_ucred->cr_prison != NULL)
160 uap->level = VARSYM_PRISON;
163 (error = priv_check_cred(td->td_ucred, PRIV_VARSYM_SYS, 0)) != 0)
167 /* XXX check jail / implement per-jail user */
171 (void)varsymmake(uap->level, name, NULL);
172 error = varsymmake(uap->level, name, buf);
174 error = varsymmake(uap->level, name, NULL);
186 * varsym_get() system call
188 * (int mask, const char *wild, char *buf, int bufsize)
193 sys_varsym_get(struct varsym_get_args *uap)
195 char wild[MAXVARSYM_NAME];
201 if ((error = copyinstr(uap->wild, wild, sizeof(wild), NULL)) != 0)
203 sym = varsymfind(uap->mask, wild, strlen(wild));
208 dlen = strlen(sym->vs_data);
209 if (dlen < uap->bufsize) {
210 copyout(sym->vs_data, uap->buf, dlen + 1);
211 } else if (uap->bufsize) {
212 copyout("", uap->buf, 1);
214 uap->sysmsg_result = dlen + 1;
222 * varsym_list() system call
224 * (int level, char *buf, int maxsize, int *marker)
229 sys_varsym_list(struct varsym_list_args *uap)
231 struct varsymset *vss;
232 struct varsyment *ve;
243 * Get the marker from userspace.
246 if ((error = copyin(uap->marker, &marker, sizeof(marker))) != 0)
250 * Figure out the varsym set.
254 p = lp ? lp->lwp_proc : NULL;
258 switch (uap->level) {
261 vss = &p->p_varsymset;
265 vss = &td->td_ucred->cr_uidinfo->ui_varsymset;
268 vss = &varsymset_sys;
271 if (lp && td->td_ucred->cr_prison)
272 vss = &td->td_ucred->cr_prison->pr_varsymset;
281 * Loop through the variables and dump them to uap->buf
287 lockmgr(&vss->vx_lock, LK_SHARED);
288 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
289 varsym_t sym = ve->ve_sym;
290 int namelen = strlen(sym->vs_name);
291 int datalen = strlen(sym->vs_data);
292 int totlen = namelen + datalen + 2;
295 * Skip to our index point
303 * Stop if there is insufficient space in the user buffer.
304 * If we haven't stored anything yet return EOVERFLOW.
305 * Note that the marker index (i) does not change.
307 if (bytes + totlen > uap->maxsize) {
314 error = copyout(sym->vs_name, uap->buf + bytes, namelen + 1);
316 bytes += namelen + 1;
317 error = copyout(sym->vs_data, uap->buf + bytes, datalen + 1);
319 bytes += datalen + 1;
321 bytes -= namelen + 1; /* revert if error */
329 lockmgr(&vss->vx_lock, LK_RELEASE);
332 * Save the marker back. If no error occured and earlyterm is clear
333 * the marker is set to -1 indicating that the variable list has been
334 * exhausted. If no error occured the number of bytes loaded into
335 * the buffer will be returned, otherwise the syscall code returns -1.
337 if (error == 0 && earlyterm == 0)
342 error = copyout(&marker, uap->marker, sizeof(marker));
343 uap->sysmsg_result = bytes;
350 * Lookup a variant symlink. XXX use a hash table.
354 varsymlookup(struct varsymset *vss, const char *name, int namelen)
356 struct varsyment *ve;
358 KKASSERT(lockstatus(&vss->vx_lock, curthread) != 0);
359 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
360 varsym_t var = ve->ve_sym;
361 if (var->vs_namelen == namelen &&
362 bcmp(name, var->vs_name, namelen) == 0
372 vsslock(struct varsymset **vss, struct varsymset *n)
375 lockmgr(&(*vss)->vx_lock, LK_RELEASE);
377 lockmgr(&n->vx_lock, LK_SHARED);
382 varsymfind(int mask, const char *name, int namelen)
384 struct varsyment *ve = NULL;
385 struct varsymset *vss = NULL;
393 p = lp ? lp->lwp_proc : NULL;
395 if ((mask & (VARSYM_PROC_MASK|VARSYM_USER_MASK)) && lp != NULL) {
396 if (mask & VARSYM_PROC_MASK) {
397 vsslock(&vss, &p->p_varsymset);
398 ve = varsymlookup(vss, name, namelen);
400 if (ve == NULL && (mask & VARSYM_USER_MASK)) {
401 vsslock(&vss, &td->td_ucred->cr_uidinfo->ui_varsymset);
402 ve = varsymlookup(vss, name, namelen);
405 if (ve == NULL && (mask & VARSYM_SYS_MASK)) {
406 if (lp != NULL && td->td_ucred->cr_prison) {
407 vsslock(&vss, &td->td_ucred->cr_prison->pr_varsymset);
408 ve = varsymlookup(vss, name, namelen);
410 vsslock(&vss, &varsymset_sys);
411 ve = varsymlookup(vss, name, namelen);
416 atomic_add_int(&sym->vs_refs, 1);
421 lockmgr(&vss->vx_lock, LK_RELEASE);
426 varsymmake(int level, const char *name, const char *data)
428 struct varsymset *vss = NULL;
429 struct varsyment *ve;
434 int namelen = strlen(name);
440 p = lp ? lp->lwp_proc : NULL;
445 vss = &p->p_varsymset;
449 vss = &td->td_ucred->cr_uidinfo->ui_varsymset;
452 vss = &varsymset_sys;
455 if (lp && td->td_ucred->cr_prison)
456 vss = &td->td_ucred->cr_prison->pr_varsymset;
462 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
463 if (data && vss->vx_setsize >= MAXVARSYM_SET) {
466 datalen = strlen(data);
467 ve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
468 sym = kmalloc(sizeof(struct varsym) + namelen + datalen + 2, M_VARSYM, M_WAITOK);
471 sym->vs_namelen = namelen;
472 sym->vs_name = (char *)(sym + 1);
473 sym->vs_data = sym->vs_name + namelen + 1;
474 strcpy(sym->vs_name, name);
475 strcpy(sym->vs_data, data);
476 TAILQ_INSERT_TAIL(&vss->vx_queue, ve, ve_entry);
477 vss->vx_setsize += sizeof(struct varsyment) + sizeof(struct varsym) + namelen + datalen + 8;
480 if ((ve = varsymlookup(vss, name, namelen)) != NULL) {
481 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
482 vss->vx_setsize -= sizeof(struct varsyment) + sizeof(struct varsym) + namelen + strlen(ve->ve_sym->vs_data) + 8;
483 varsymdrop(ve->ve_sym);
490 lockmgr(&vss->vx_lock, LK_RELEASE);
495 varsymdrop(varsym_t sym)
497 KKASSERT(sym->vs_refs > 0);
498 if (atomic_fetchadd_int(&sym->vs_refs, -1) == 1) {
499 kfree(sym, M_VARSYM);
504 * Insert a duplicate of ve in vss. Does not do any locking,
505 * so it is the callers responsibility to make sure nobody
506 * else can mess with the TAILQ in vss at the same time.
509 varsymdup(struct varsymset *vss, struct varsyment *ve)
511 struct varsyment *nve;
513 nve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
514 nve->ve_sym = ve->ve_sym;
515 ++nve->ve_sym->vs_refs; /* can't be reached, no need for atomic add */
517 * We're only called through varsymset_init() so vss is not yet reachable,
520 TAILQ_INSERT_TAIL(&vss->vx_queue, nve, ve_entry);
524 varsymset_init(struct varsymset *vss, struct varsymset *copy)
526 struct varsyment *ve;
528 TAILQ_INIT(&vss->vx_queue);
529 lockinit(&vss->vx_lock, "vx", 0, 0);
531 TAILQ_FOREACH(ve, ©->vx_queue, ve_entry) {
534 vss->vx_setsize = copy->vx_setsize;
539 varsymset_clean(struct varsymset *vss)
541 struct varsyment *ve;
543 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
544 while ((ve = TAILQ_FIRST(&vss->vx_queue)) != NULL) {
545 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
546 varsymdrop(ve->ve_sym);
550 lockmgr(&vss->vx_lock, LK_RELEASE);