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)
133 sys_varsym_set(struct varsym_set_args *uap)
135 char name[MAXVARSYM_NAME];
142 if ((error = copyinstr(uap->name, name, sizeof(name), NULL)) != 0)
144 buf = kmalloc(MAXVARSYM_DATA, M_TEMP, M_WAITOK);
146 (error = copyinstr(uap->data, buf, MAXVARSYM_DATA, NULL)) != 0)
152 if (p != NULL && p->p_ucred->cr_prison != NULL)
153 uap->level = VARSYM_PRISON;
156 (error = priv_check_cred(p->p_ucred, PRIV_VARSYM_SYS, 0)) != 0)
160 /* XXX check jail / implement per-jail user */
164 (void)varsymmake(uap->level, name, NULL);
165 error = varsymmake(uap->level, name, buf);
167 error = varsymmake(uap->level, name, NULL);
178 * varsym_get() system call
180 * (int mask, const char *wild, char *buf, int bufsize)
183 sys_varsym_get(struct varsym_get_args *uap)
185 char wild[MAXVARSYM_NAME];
190 if ((error = copyinstr(uap->wild, wild, sizeof(wild), NULL)) != 0)
192 sym = varsymfind(uap->mask, wild, strlen(wild));
197 dlen = strlen(sym->vs_data);
198 if (dlen < uap->bufsize) {
199 copyout(sym->vs_data, uap->buf, dlen + 1);
200 } else if (uap->bufsize) {
201 copyout("", uap->buf, 1);
203 uap->sysmsg_result = dlen + 1;
210 * varsym_list() system call
212 * (int level, char *buf, int maxsize, int *marker)
215 sys_varsym_list(struct varsym_list_args *uap)
217 struct varsymset *vss;
218 struct varsyment *ve;
227 * Get the marker from userspace.
229 if ((error = copyin(uap->marker, &marker, sizeof(marker))) != 0)
233 * Figure out the varsym set.
238 switch (uap->level) {
241 vss = &p->p_varsymset;
245 vss = &p->p_ucred->cr_uidinfo->ui_varsymset;
248 vss = &varsymset_sys;
251 if (p != NULL && p->p_ucred->cr_prison != NULL)
252 vss = &p->p_ucred->cr_prison->pr_varsymset;
261 * Loop through the variables and dump them to uap->buf
267 lockmgr(&vss->vx_lock, LK_SHARED);
268 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
269 varsym_t sym = ve->ve_sym;
270 int namelen = strlen(sym->vs_name);
271 int datalen = strlen(sym->vs_data);
272 int totlen = namelen + datalen + 2;
275 * Skip to our index point
283 * Stop if there is insufficient space in the user buffer.
284 * If we haven't stored anything yet return EOVERFLOW.
285 * Note that the marker index (i) does not change.
287 if (bytes + totlen > uap->maxsize) {
294 error = copyout(sym->vs_name, uap->buf + bytes, namelen + 1);
296 bytes += namelen + 1;
297 error = copyout(sym->vs_data, uap->buf + bytes, datalen + 1);
299 bytes += datalen + 1;
301 bytes -= namelen + 1; /* revert if error */
309 lockmgr(&vss->vx_lock, LK_RELEASE);
312 * Save the marker back. If no error occured and earlyterm is clear
313 * the marker is set to -1 indicating that the variable list has been
314 * exhausted. If no error occured the number of bytes loaded into
315 * the buffer will be returned, otherwise the syscall code returns -1.
317 if (error == 0 && earlyterm == 0)
322 error = copyout(&marker, uap->marker, sizeof(marker));
323 uap->sysmsg_result = bytes;
329 * Lookup a variant symlink. XXX use a hash table.
333 varsymlookup(struct varsymset *vss, const char *name, int namelen)
335 struct varsyment *ve;
337 KKASSERT(lockstatus(&vss->vx_lock, curthread) != 0);
338 TAILQ_FOREACH(ve, &vss->vx_queue, ve_entry) {
339 varsym_t var = ve->ve_sym;
340 if (var->vs_namelen == namelen &&
341 bcmp(name, var->vs_name, namelen) == 0
351 vsslock(struct varsymset **vss, struct varsymset *n)
354 lockmgr(&(*vss)->vx_lock, LK_RELEASE);
356 lockmgr(&n->vx_lock, LK_SHARED);
361 varsymfind(int mask, const char *name, int namelen)
363 struct proc *p = curproc;
364 struct varsyment *ve = NULL;
365 struct varsymset *vss = NULL;
368 if ((mask & (VARSYM_PROC_MASK|VARSYM_USER_MASK)) && p != NULL) {
369 if (mask & VARSYM_PROC_MASK) {
370 vsslock(&vss, &p->p_varsymset);
371 ve = varsymlookup(vss, name, namelen);
373 if (ve == NULL && (mask & VARSYM_USER_MASK)) {
374 vsslock(&vss, &p->p_ucred->cr_uidinfo->ui_varsymset);
375 ve = varsymlookup(vss, name, namelen);
378 if (ve == NULL && (mask & VARSYM_SYS_MASK)) {
379 if (p != NULL && p->p_ucred->cr_prison) {
380 vsslock(&vss, &p->p_ucred->cr_prison->pr_varsymset);
381 ve = varsymlookup(vss, name, namelen);
383 vsslock(&vss, &varsymset_sys);
384 ve = varsymlookup(vss, name, namelen);
389 atomic_add_int(&sym->vs_refs, 1);
393 lockmgr(&vss->vx_lock, LK_RELEASE);
398 varsymmake(int level, const char *name, const char *data)
400 struct varsymset *vss = NULL;
401 struct varsyment *ve;
402 struct proc *p = curproc;
404 int namelen = strlen(name);
411 vss = &p->p_varsymset;
415 vss = &p->p_ucred->cr_uidinfo->ui_varsymset;
418 vss = &varsymset_sys;
421 if (p != NULL && p->p_ucred->cr_prison != NULL)
422 vss = &p->p_ucred->cr_prison->pr_varsymset;
428 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
429 if (data && vss->vx_setsize >= MAXVARSYM_SET) {
432 datalen = strlen(data);
433 ve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
434 sym = kmalloc(sizeof(struct varsym) + namelen + datalen + 2, M_VARSYM, M_WAITOK);
437 sym->vs_namelen = namelen;
438 sym->vs_name = (char *)(sym + 1);
439 sym->vs_data = sym->vs_name + namelen + 1;
440 strcpy(sym->vs_name, name);
441 strcpy(sym->vs_data, data);
442 TAILQ_INSERT_TAIL(&vss->vx_queue, ve, ve_entry);
443 vss->vx_setsize += sizeof(struct varsyment) + sizeof(struct varsym) + namelen + datalen + 8;
446 if ((ve = varsymlookup(vss, name, namelen)) != NULL) {
447 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
448 vss->vx_setsize -= sizeof(struct varsyment) + sizeof(struct varsym) + namelen + strlen(ve->ve_sym->vs_data) + 8;
449 varsymdrop(ve->ve_sym);
456 lockmgr(&vss->vx_lock, LK_RELEASE);
461 varsymdrop(varsym_t sym)
463 KKASSERT(sym->vs_refs > 0);
464 if (atomic_fetchadd_int(&sym->vs_refs, -1) == 1) {
465 kfree(sym, M_VARSYM);
470 * Insert a duplicate of ve in vss. Does not do any locking,
471 * so it is the callers responsibility to make sure nobody
472 * else can mess with the TAILQ in vss at the same time.
475 varsymdup(struct varsymset *vss, struct varsyment *ve)
477 struct varsyment *nve;
479 nve = kmalloc(sizeof(struct varsyment), M_VARSYM, M_WAITOK|M_ZERO);
480 nve->ve_sym = ve->ve_sym;
481 ++nve->ve_sym->vs_refs; /* can't be reached, no need for atomic add */
483 * We're only called through varsymset_init() so vss is not yet reachable,
486 TAILQ_INSERT_TAIL(&vss->vx_queue, nve, ve_entry);
490 varsymset_init(struct varsymset *vss, struct varsymset *copy)
492 struct varsyment *ve;
494 TAILQ_INIT(&vss->vx_queue);
495 lockinit(&vss->vx_lock, "vx", 0, 0);
497 TAILQ_FOREACH(ve, ©->vx_queue, ve_entry) {
500 vss->vx_setsize = copy->vx_setsize;
505 varsymset_clean(struct varsymset *vss)
507 struct varsyment *ve;
509 lockmgr(&vss->vx_lock, LK_EXCLUSIVE);
510 while ((ve = TAILQ_FIRST(&vss->vx_queue)) != NULL) {
511 TAILQ_REMOVE(&vss->vx_queue, ve, ve_entry);
512 varsymdrop(ve->ve_sym);
516 lockmgr(&vss->vx_lock, LK_RELEASE);