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Add a global mutex, accept_filter_mtx, to protect the global list of

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accept filters and prevent read-modify-write races.
This commit is contained in:
Robert Watson 2004-06-01 04:08:48 +00:00
parent 897ade31a2
commit d087080c1f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=129920
1 changed files with 17 additions and 7 deletions
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24
sys/kern/uipc_accf.c
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@ -35,15 +35,23 @@ __FBSDID("$FreeBSD$");
#include <sys/systm.h>
#include <sys/domain.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/queue.h>
static struct mtx accept_filter_mtx;
MTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx",
MTX_DEF);
#define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx)
#define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx)
static SLIST_HEAD(, accept_filter) accept_filtlsthd =
SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
@ -67,12 +75,15 @@ accept_filt_add(struct accept_filter *filt)
{
struct accept_filter *p;
ACCEPT_FILTER_LOCK();
SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
if (strcmp(p->accf_name, filt->accf_name) == 0) {
if (p->accf_callback != NULL) {
ACCEPT_FILTER_UNLOCK();
return (EEXIST);
} else {
p->accf_callback = filt->accf_callback;
ACCEPT_FILTER_UNLOCK();
FREE(filt, M_ACCF);
return (0);
}
@ -80,6 +91,7 @@ accept_filt_add(struct accept_filter *filt)
if (p == NULL)
SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
ACCEPT_FILTER_UNLOCK();
return (0);
}
@ -101,11 +113,13 @@ accept_filt_get(char *name)
{
struct accept_filter *p;
ACCEPT_FILTER_LOCK();
SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
if (strcmp(p->accf_name, name) == 0)
return (p);
break;
ACCEPT_FILTER_UNLOCK();
return (NULL);
return (p);
}
int
@ -113,15 +127,13 @@ accept_filt_generic_mod_event(module_t mod, int event, void *data)
{
struct accept_filter *p;
struct accept_filter *accfp = (struct accept_filter *) data;
int s, error;
int error;
switch (event) {
case MOD_LOAD:
MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, M_WAITOK);
bcopy(accfp, p, sizeof(*p));
s = splnet();
error = accept_filt_add(p);
splx(s);
break;
case MOD_UNLOAD:
@ -132,9 +144,7 @@ accept_filt_generic_mod_event(module_t mod, int event, void *data)
* in the struct accept_filter.
*/
if (unloadable != 0) {
s = splnet();
error = accept_filt_del(accfp->accf_name);
splx(s);
} else
error = EOPNOTSUPP;
break;