freebsd-dev/sys/fs/devfs/devfs_dir.c

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/*-
* Copyright (c) 2010 Jaakko Heinonen <jh@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/types.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/systm.h>
#include <sys/sx.h>
#include <fs/devfs/devfs.h>
#include <fs/devfs/devfs_int.h>
struct dirlistent {
char *dir;
int refcnt;
LIST_ENTRY(dirlistent) link;
};
static LIST_HEAD(, dirlistent) devfs_dirlist =
LIST_HEAD_INITIALIZER(devfs_dirlist);
static MALLOC_DEFINE(M_DEVFS4, "DEVFS4", "DEVFS directory list");
static struct mtx dirlist_mtx;
MTX_SYSINIT(dirlist_mtx, &dirlist_mtx, "devfs dirlist lock", MTX_DEF);
/* Returns 1 if the path is in the directory list. */
int
devfs_dir_find(const char *path)
{
struct dirlistent *dle;
mtx_lock(&dirlist_mtx);
LIST_FOREACH(dle, &devfs_dirlist, link) {
if (devfs_pathpath(dle->dir, path) != 0) {
mtx_unlock(&dirlist_mtx);
return (1);
}
}
mtx_unlock(&dirlist_mtx);
return (0);
}
static struct dirlistent *
devfs_dir_findent_locked(const char *dir)
{
struct dirlistent *dle;
mtx_assert(&dirlist_mtx, MA_OWNED);
LIST_FOREACH(dle, &devfs_dirlist, link) {
if (strcmp(dir, dle->dir) == 0)
return (dle);
}
return (NULL);
}
static void
devfs_dir_ref(const char *dir)
{
struct dirlistent *dle, *dle_new;
if (*dir == '\0')
return;
dle_new = malloc(sizeof(*dle), M_DEVFS4, M_WAITOK);
dle_new->dir = strdup(dir, M_DEVFS4);
dle_new->refcnt = 1;
mtx_lock(&dirlist_mtx);
dle = devfs_dir_findent_locked(dir);
if (dle != NULL) {
dle->refcnt++;
mtx_unlock(&dirlist_mtx);
free(dle_new->dir, M_DEVFS4);
free(dle_new, M_DEVFS4);
return;
}
LIST_INSERT_HEAD(&devfs_dirlist, dle_new, link);
mtx_unlock(&dirlist_mtx);
}
void
devfs_dir_ref_de(struct devfs_mount *dm, struct devfs_dirent *de)
{
char dirname[SPECNAMELEN + 1], *namep;
namep = devfs_fqpn(dirname, dm, de, NULL);
KASSERT(namep != NULL, ("devfs_ref_dir_de: NULL namep"));
devfs_dir_ref(namep);
}
static void
devfs_dir_unref(const char *dir)
{
struct dirlistent *dle;
if (*dir == '\0')
return;
mtx_lock(&dirlist_mtx);
dle = devfs_dir_findent_locked(dir);
KASSERT(dle != NULL, ("devfs_dir_unref: dir %s not referenced", dir));
dle->refcnt--;
KASSERT(dle->refcnt >= 0, ("devfs_dir_unref: negative refcnt"));
if (dle->refcnt == 0) {
LIST_REMOVE(dle, link);
mtx_unlock(&dirlist_mtx);
free(dle->dir, M_DEVFS4);
free(dle, M_DEVFS4);
} else
mtx_unlock(&dirlist_mtx);
}
void
devfs_dir_unref_de(struct devfs_mount *dm, struct devfs_dirent *de)
{
char dirname[SPECNAMELEN + 1], *namep;
namep = devfs_fqpn(dirname, dm, de, NULL);
KASSERT(namep != NULL, ("devfs_unref_dir_de: NULL namep"));
devfs_dir_unref(namep);
}
/* Returns 1 if the path p1 contains the path p2. */
int
devfs_pathpath(const char *p1, const char *p2)
{
for (;;p1++, p2++) {
if (*p1 != *p2) {
if (*p1 == '/' && *p2 == '\0')
return (1);
else
return (0);
} else if (*p1 == '\0')
return (1);
}
/* NOTREACHED */
}