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,
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27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/kern/kern_varsym.c,v 1.9 2007/04/30 07:18:54 dillon Exp $
38 * This module implements variable storage and management for variant
39 * symlinks. These variables may also be used for general purposes.
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/ucred.h>
46 #include <sys/resourcevar.h>
50 #include <sys/queue.h>
51 #include <sys/sysctl.h>
52 #include <sys/malloc.h>
53 #include <sys/varsym.h>
54 #include <sys/sysproto.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 p = lp ? lp->lwp_proc : NULL;
148 if ((error = copyinstr(uap->name, name, sizeof(name), NULL)) != 0)
150 buf = kmalloc(MAXVARSYM_DATA, M_TEMP, M_WAITOK);
152 (error = copyinstr(uap->data, buf, MAXVARSYM_DATA, NULL)) != 0)
161 if (lp != NULL && td->td_ucred->cr_prison != NULL)
162 uap->level = VARSYM_PRISON;
165 (error = priv_check_cred(td->td_ucred, PRIV_VARSYM_SYS, 0)) != 0)
169 /* XXX check jail / implement per-jail user */
173 (void)varsymmake(uap->level, name, NULL);
174 error = varsymmake(uap->level, name, buf);
176 error = varsymmake(uap->level, name, NULL);
188 * varsym_get() system call
190 * (int mask, const char *wild, char *buf, int bufsize)
195 sys_varsym_get(struct varsym_get_args *uap)
197 char wild[MAXVARSYM_NAME];
203 if ((error = copyinstr(uap->wild, wild, sizeof(wild), NULL)) != 0)
205 sym = varsymfind(uap->mask, wild, strlen(wild));
210 dlen = strlen(sym->vs_data);
211 if (dlen < uap->bufsize) {
212 copyout(sym->vs_data, uap->buf, dlen + 1);
213 } else if (uap->bufsize) {
214 copyout("", uap->buf, 1);
216 uap->sysmsg_result = dlen + 1;
224 * varsym_list() system call
226 * (int level, char *buf, int maxsize, int *marker)
231 sys_varsym_list(struct varsym_list_args *uap)
233 struct varsymset *vss;
234 struct varsyment *ve;
245 * Get the marker from userspace.
248 if ((error = copyin(uap->marker, &marker, sizeof(marker))) != 0)
252 * Figure out the varsym set.
256 p = lp ? lp->lwp_proc : NULL;
260 switch (uap->level) {
263 vss = &p->p_varsymset;
267 vss = &td->td_ucred->cr_uidinfo->ui_varsymset;
270 vss = &varsymset_sys;
273 if (lp && td->td_ucred->cr_prison)
274 vss = &td->td_ucred->cr_prison->pr_varsymset;
283 * Loop through the variables and dump them to uap->buf
289 lockmgr(&vss->vx_lock, LK_SHARED);
290 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
291 varsym_t sym = ve->ve_sym;
292 int namelen = strlen(sym->vs_name);
293 int datalen = strlen(sym->vs_data);
294 int totlen = namelen + datalen + 2;
297 * Skip to our index point
305 * Stop if there is insufficient space in the user buffer.
306 * If we haven't stored anything yet return EOVERFLOW.
307 * Note that the marker index (i) does not change.
309 if (bytes + totlen > uap->maxsize) {
316 error = copyout(sym->vs_name, uap->buf + bytes, namelen + 1);
318 bytes += namelen + 1;
319 error = copyout(sym->vs_data, uap->buf + bytes, datalen + 1);
321 bytes += datalen + 1;
323 bytes -= namelen + 1; /* revert if error */
331 lockmgr(&vss->vx_lock, LK_RELEASE);
334 * Save the marker back. If no error occured and earlyterm is clear
335 * the marker is set to -1 indicating that the variable list has been
336 * exhausted. If no error occured the number of bytes loaded into
337 * the buffer will be returned, otherwise the syscall code returns -1.
339 if (error == 0 && earlyterm == 0)
344 error = copyout(&marker, uap->marker, sizeof(marker));
345 uap->sysmsg_result = bytes;
352 * Lookup a variant symlink. XXX use a hash table.
356 varsymlookup(struct varsymset *vss, const char *name, int namelen)
358 struct varsyment *ve;
360 KKASSERT(lockstatus(&vss->vx_lock, curthread) != 0);
361 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
362 varsym_t var = ve->ve_sym;
363 if (var->vs_namelen == namelen &&
364 bcmp(name, var->vs_name, namelen) == 0
374 vsslock(struct varsymset **vss, struct varsymset *n)
377 lockmgr(&(*vss)->vx_lock, LK_RELEASE);
379 lockmgr(&n->vx_lock, LK_SHARED);
384 varsymfind(int mask, const char *name, int namelen)
386 struct varsyment *ve = NULL;
387 struct varsymset *vss = NULL;
395 p = lp ? lp->lwp_proc : NULL;
397 if ((mask & (VARSYM_PROC_MASK|VARSYM_USER_MASK)) && lp != NULL) {
398 if (mask & VARSYM_PROC_MASK) {
399 vsslock(&vss, &p->p_varsymset);
400 ve = varsymlookup(vss, name, namelen);
402 if (ve == NULL && (mask & VARSYM_USER_MASK)) {
403 vsslock(&vss, &td->td_ucred->cr_uidinfo->ui_varsymset);
404 ve = varsymlookup(vss, name, namelen);
407 if (ve == NULL && (mask & VARSYM_SYS_MASK)) {
408 if (lp != NULL && td->td_ucred->cr_prison) {
409 vsslock(&vss, &td->td_ucred->cr_prison->pr_varsymset);
410 ve = varsymlookup(vss, name, namelen);
412 vsslock(&vss, &varsymset_sys);
413 ve = varsymlookup(vss, name, namelen);
418 atomic_add_int(&sym->vs_refs, 1);
422 lockmgr(&vss->vx_lock, LK_RELEASE);
427 varsymmake(int level, const char *name, const char *data)
429 struct varsymset *vss = NULL;
430 struct varsyment *ve;
435 int namelen = strlen(name);
441 p = lp ? lp->lwp_proc : NULL;
446 vss = &p->p_varsymset;
450 vss = &td->td_ucred->cr_uidinfo->ui_varsymset;
453 vss = &varsymset_sys;
456 if (lp && td->td_ucred->cr_prison)
457 vss = &td->td_ucred->cr_prison->pr_varsymset;
463 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
464 if (data && vss->vx_setsize >= MAXVARSYM_SET) {
467 datalen = strlen(data);
468 ve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
469 sym = kmalloc(sizeof(struct varsym) + namelen + datalen + 2, M_VARSYM, M_WAITOK);
472 sym->vs_namelen = namelen;
473 sym->vs_name = (char *)(sym + 1);
474 sym->vs_data = sym->vs_name + namelen + 1;
475 strcpy(sym->vs_name, name);
476 strcpy(sym->vs_data, data);
477 TAILQ_INSERT_TAIL(&vss->vx_queue, ve, ve_entry);
478 vss->vx_setsize += sizeof(struct varsyment) + sizeof(struct varsym) + namelen + datalen + 8;
481 if ((ve = varsymlookup(vss, name, namelen)) != NULL) {
482 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
483 vss->vx_setsize -= sizeof(struct varsyment) + sizeof(struct varsym) + namelen + strlen(ve->ve_sym->vs_data) + 8;
484 varsymdrop(ve->ve_sym);
491 lockmgr(&vss->vx_lock, LK_RELEASE);
496 varsymdrop(varsym_t sym)
498 KKASSERT(sym->vs_refs > 0);
499 if (atomic_fetchadd_int(&sym->vs_refs, -1) == 1) {
500 kfree(sym, M_VARSYM);
505 * Insert a duplicate of ve in vss. Does not do any locking,
506 * so it is the callers responsibility to make sure nobody
507 * else can mess with the TAILQ in vss at the same time.
510 varsymdup(struct varsymset *vss, struct varsyment *ve)
512 struct varsyment *nve;
514 nve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
515 nve->ve_sym = ve->ve_sym;
516 ++nve->ve_sym->vs_refs; /* can't be reached, no need for atomic add */
518 * We're only called through varsymset_init() so vss is not yet reachable,
521 TAILQ_INSERT_TAIL(&vss->vx_queue, nve, ve_entry);
525 varsymset_init(struct varsymset *vss, struct varsymset *copy)
527 struct varsyment *ve;
529 TAILQ_INIT(&vss->vx_queue);
530 lockinit(&vss->vx_lock, "vx", 0, 0);
532 TAILQ_FOREACH(ve, ©->vx_queue, ve_entry) {
535 vss->vx_setsize = copy->vx_setsize;
540 varsymset_clean(struct varsymset *vss)
542 struct varsyment *ve;
544 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
545 while ((ve = TAILQ_FIRST(&vss->vx_queue)) != NULL) {
546 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
547 varsymdrop(ve->ve_sym);
551 lockmgr(&vss->vx_lock, LK_RELEASE);