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freebsd-skq/sys/kern/uipc_sem.c
mjg a9faac8f4b Avoid dynamic syscall overhead for statically compiled modules. 
The kernel tracks syscall users so that modules can safely unregister them.

But if the module is not unloadable or was compiled into the kernel, there is
no need to do this.

Achieve this by adding SY_THR_STATIC_KLD macro which expands to SY_THR_STATIC
during kernel build and 0 otherwise.

Reviewed by:	kib (previous version)
MFC after:	2 weeks
2014-10-26 19:42:44 +00:00

1066 lines
24 KiB
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Raw Blame History

/*-
* Copyright (c) 2002 Alfred Perlstein <alfred@FreeBSD.org>
* Copyright (c) 2003-2005 SPARTA, Inc.
* Copyright (c) 2005 Robert N. M. Watson
* All rights reserved.
*
* This software was developed for the FreeBSD Project in part by Network
* Associates Laboratories, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
* as part of the DARPA CHATS research program.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_posix.h"
#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/condvar.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/fnv_hash.h>
#include <sys/kernel.h>
#include <sys/ksem.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/posix4.h>
#include <sys/_semaphore.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/sx.h>
#include <sys/user.h>
#include <sys/vnode.h>
#include <security/mac/mac_framework.h>
FEATURE(p1003_1b_semaphores, "POSIX P1003.1B semaphores support");
/*
* TODO
*
* - Resource limits?
* - Replace global sem_lock with mtx_pool locks?
* - Add a MAC check_create() hook for creating new named semaphores.
*/
#ifndef SEM_MAX
#define SEM_MAX 30
#endif
#ifdef SEM_DEBUG
#define DP(x) printf x
#else
#define DP(x)
#endif
struct ksem_mapping {
char *km_path;
Fnv32_t km_fnv;
struct ksem *km_ksem;
LIST_ENTRY(ksem_mapping) km_link;
};
static MALLOC_DEFINE(M_KSEM, "ksem", "semaphore file descriptor");
static LIST_HEAD(, ksem_mapping) *ksem_dictionary;
static struct sx ksem_dict_lock;
static struct mtx ksem_count_lock;
static struct mtx sem_lock;
static u_long ksem_hash;
static int ksem_dead;
#define KSEM_HASH(fnv) (&ksem_dictionary[(fnv) & ksem_hash])
static int nsems = 0;
SYSCTL_DECL(_p1003_1b);
SYSCTL_INT(_p1003_1b, OID_AUTO, nsems, CTLFLAG_RD, &nsems, 0,
"Number of active kernel POSIX semaphores");
static int kern_sem_wait(struct thread *td, semid_t id, int tryflag,
struct timespec *abstime);
static int ksem_access(struct ksem *ks, struct ucred *ucred);
static struct ksem *ksem_alloc(struct ucred *ucred, mode_t mode,
unsigned int value);
static int ksem_create(struct thread *td, const char *path,
semid_t *semidp, mode_t mode, unsigned int value,
int flags, int compat32);
static void ksem_drop(struct ksem *ks);
static int ksem_get(struct thread *td, semid_t id, cap_rights_t *rightsp,
struct file **fpp);
static struct ksem *ksem_hold(struct ksem *ks);
static void ksem_insert(char *path, Fnv32_t fnv, struct ksem *ks);
static struct ksem *ksem_lookup(char *path, Fnv32_t fnv);
static void ksem_module_destroy(void);
static int ksem_module_init(void);
static int ksem_remove(char *path, Fnv32_t fnv, struct ucred *ucred);
static int sem_modload(struct module *module, int cmd, void *arg);
static fo_stat_t ksem_stat;
static fo_close_t ksem_closef;
static fo_chmod_t ksem_chmod;
static fo_chown_t ksem_chown;
static fo_fill_kinfo_t ksem_fill_kinfo;
/* File descriptor operations. */
static struct fileops ksem_ops = {
.fo_read = invfo_rdwr,
.fo_write = invfo_rdwr,
.fo_truncate = invfo_truncate,
.fo_ioctl = invfo_ioctl,
.fo_poll = invfo_poll,
.fo_kqfilter = invfo_kqfilter,
.fo_stat = ksem_stat,
.fo_close = ksem_closef,
.fo_chmod = ksem_chmod,
.fo_chown = ksem_chown,
.fo_sendfile = invfo_sendfile,
.fo_fill_kinfo = ksem_fill_kinfo,
.fo_flags = DFLAG_PASSABLE
};
FEATURE(posix_sem, "POSIX semaphores");
static int
ksem_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
struct thread *td)
{
struct ksem *ks;
#ifdef MAC
int error;
#endif
ks = fp->f_data;
#ifdef MAC
error = mac_posixsem_check_stat(active_cred, fp->f_cred, ks);
if (error)
return (error);
#endif
/*
* Attempt to return sanish values for fstat() on a semaphore
* file descriptor.
*/
bzero(sb, sizeof(*sb));
mtx_lock(&sem_lock);
sb->st_atim = ks->ks_atime;
sb->st_ctim = ks->ks_ctime;
sb->st_mtim = ks->ks_mtime;
sb->st_birthtim = ks->ks_birthtime;
sb->st_uid = ks->ks_uid;
sb->st_gid = ks->ks_gid;
sb->st_mode = S_IFREG | ks->ks_mode; /* XXX */
mtx_unlock(&sem_lock);
return (0);
}
static int
ksem_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
struct thread *td)
{
struct ksem *ks;
int error;
error = 0;
ks = fp->f_data;
mtx_lock(&sem_lock);
#ifdef MAC
error = mac_posixsem_check_setmode(active_cred, ks, mode);
if (error != 0)
goto out;
#endif
error = vaccess(VREG, ks->ks_mode, ks->ks_uid, ks->ks_gid, VADMIN,
active_cred, NULL);
if (error != 0)
goto out;
ks->ks_mode = mode & ACCESSPERMS;
out:
mtx_unlock(&sem_lock);
return (error);
}
static int
ksem_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
struct thread *td)
{
struct ksem *ks;
int error;
error = 0;
ks = fp->f_data;
mtx_lock(&sem_lock);
#ifdef MAC
error = mac_posixsem_check_setowner(active_cred, ks, uid, gid);
if (error != 0)
goto out;
#endif
if (uid == (uid_t)-1)
uid = ks->ks_uid;
if (gid == (gid_t)-1)
gid = ks->ks_gid;
if (((uid != ks->ks_uid && uid != active_cred->cr_uid) ||
(gid != ks->ks_gid && !groupmember(gid, active_cred))) &&
(error = priv_check_cred(active_cred, PRIV_VFS_CHOWN, 0)))
goto out;
ks->ks_uid = uid;
ks->ks_gid = gid;
out:
mtx_unlock(&sem_lock);
return (error);
}
static int
ksem_closef(struct file *fp, struct thread *td)
{
struct ksem *ks;
ks = fp->f_data;
fp->f_data = NULL;
ksem_drop(ks);
return (0);
}
static int
ksem_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
{
struct ksem *ks;
kif->kf_type = KF_TYPE_SEM;
ks = fp->f_data;
mtx_lock(&sem_lock);
kif->kf_un.kf_sem.kf_sem_value = ks->ks_value;
kif->kf_un.kf_sem.kf_sem_mode = S_IFREG | ks->ks_mode; /* XXX */
mtx_unlock(&sem_lock);
if (ks->ks_path != NULL) {
sx_slock(&ksem_dict_lock);
if (ks->ks_path != NULL)
strlcpy(kif->kf_path, ks->ks_path, sizeof(kif->kf_path));
sx_sunlock(&ksem_dict_lock);
}
return (0);
}
/*
* ksem object management including creation and reference counting
* routines.
*/
static struct ksem *
ksem_alloc(struct ucred *ucred, mode_t mode, unsigned int value)
{
struct ksem *ks;
mtx_lock(&ksem_count_lock);
if (nsems == p31b_getcfg(CTL_P1003_1B_SEM_NSEMS_MAX) || ksem_dead) {
mtx_unlock(&ksem_count_lock);
return (NULL);
}
nsems++;
mtx_unlock(&ksem_count_lock);
ks = malloc(sizeof(*ks), M_KSEM, M_WAITOK | M_ZERO);
ks->ks_uid = ucred->cr_uid;
ks->ks_gid = ucred->cr_gid;
ks->ks_mode = mode;
ks->ks_value = value;
cv_init(&ks->ks_cv, "ksem");
vfs_timestamp(&ks->ks_birthtime);
ks->ks_atime = ks->ks_mtime = ks->ks_ctime = ks->ks_birthtime;
refcount_init(&ks->ks_ref, 1);
#ifdef MAC
mac_posixsem_init(ks);
mac_posixsem_create(ucred, ks);
#endif
return (ks);
}
static struct ksem *
ksem_hold(struct ksem *ks)
{
refcount_acquire(&ks->ks_ref);
return (ks);
}
static void
ksem_drop(struct ksem *ks)
{
if (refcount_release(&ks->ks_ref)) {
#ifdef MAC
mac_posixsem_destroy(ks);
#endif
cv_destroy(&ks->ks_cv);
free(ks, M_KSEM);
mtx_lock(&ksem_count_lock);
nsems--;
mtx_unlock(&ksem_count_lock);
}
}
/*
* Determine if the credentials have sufficient permissions for read
* and write access.
*/
static int
ksem_access(struct ksem *ks, struct ucred *ucred)
{
int error;
error = vaccess(VREG, ks->ks_mode, ks->ks_uid, ks->ks_gid,
VREAD | VWRITE, ucred, NULL);
if (error)
error = priv_check_cred(ucred, PRIV_SEM_WRITE, 0);
return (error);
}
/*
* Dictionary management. We maintain an in-kernel dictionary to map
* paths to semaphore objects. We use the FNV hash on the path to
* store the mappings in a hash table.
*/
static struct ksem *
ksem_lookup(char *path, Fnv32_t fnv)
{
struct ksem_mapping *map;
LIST_FOREACH(map, KSEM_HASH(fnv), km_link) {
if (map->km_fnv != fnv)
continue;
if (strcmp(map->km_path, path) == 0)
return (map->km_ksem);
}
return (NULL);
}
static void
ksem_insert(char *path, Fnv32_t fnv, struct ksem *ks)
{
struct ksem_mapping *map;
map = malloc(sizeof(struct ksem_mapping), M_KSEM, M_WAITOK);
map->km_path = path;
map->km_fnv = fnv;
map->km_ksem = ksem_hold(ks);
ks->ks_path = path;
LIST_INSERT_HEAD(KSEM_HASH(fnv), map, km_link);
}
static int
ksem_remove(char *path, Fnv32_t fnv, struct ucred *ucred)
{
struct ksem_mapping *map;
int error;
LIST_FOREACH(map, KSEM_HASH(fnv), km_link) {
if (map->km_fnv != fnv)
continue;
if (strcmp(map->km_path, path) == 0) {
#ifdef MAC
error = mac_posixsem_check_unlink(ucred, map->km_ksem);
if (error)
return (error);
#endif
error = ksem_access(map->km_ksem, ucred);
if (error)
return (error);
map->km_ksem->ks_path = NULL;
LIST_REMOVE(map, km_link);
ksem_drop(map->km_ksem);
free(map->km_path, M_KSEM);
free(map, M_KSEM);
return (0);
}
}
return (ENOENT);
}
static int
ksem_create_copyout_semid(struct thread *td, semid_t *semidp, int fd,
int compat32)
{
semid_t semid;
#ifdef COMPAT_FREEBSD32
int32_t semid32;
#endif
void *ptr;
size_t ptrs;
#ifdef COMPAT_FREEBSD32
if (compat32) {
semid32 = fd;
ptr = &semid32;
ptrs = sizeof(semid32);
} else {
#endif
semid = fd;
ptr = &semid;
ptrs = sizeof(semid);
compat32 = 0; /* silence gcc */
#ifdef COMPAT_FREEBSD32
}
#endif
return (copyout(ptr, semidp, ptrs));
}
/* Other helper routines. */
static int
ksem_create(struct thread *td, const char *name, semid_t *semidp, mode_t mode,
unsigned int value, int flags, int compat32)
{
struct filedesc *fdp;
struct ksem *ks;
struct file *fp;
char *path;
Fnv32_t fnv;
int error, fd;
if (value > SEM_VALUE_MAX)
return (EINVAL);
fdp = td->td_proc->p_fd;
mode = (mode & ~fdp->fd_cmask) & ACCESSPERMS;
error = falloc(td, &fp, &fd, O_CLOEXEC);
if (error) {
if (name == NULL)
error = ENOSPC;
return (error);
}
/*
* Go ahead and copyout the file descriptor now. This is a bit
* premature, but it is a lot easier to handle errors as opposed
* to later when we've possibly created a new semaphore, etc.
*/
error = ksem_create_copyout_semid(td, semidp, fd, compat32);
if (error) {
fdclose(fdp, fp, fd, td);
fdrop(fp, td);
return (error);
}
if (name == NULL) {
/* Create an anonymous semaphore. */
ks = ksem_alloc(td->td_ucred, mode, value);
if (ks == NULL)
error = ENOSPC;
else
ks->ks_flags |= KS_ANONYMOUS;
} else {
path = malloc(MAXPATHLEN, M_KSEM, M_WAITOK);
error = copyinstr(name, path, MAXPATHLEN, NULL);
/* Require paths to start with a '/' character. */
if (error == 0 && path[0] != '/')
error = EINVAL;
if (error) {
fdclose(fdp, fp, fd, td);
fdrop(fp, td);
free(path, M_KSEM);
return (error);
}
fnv = fnv_32_str(path, FNV1_32_INIT);
sx_xlock(&ksem_dict_lock);
ks = ksem_lookup(path, fnv);
if (ks == NULL) {
/* Object does not exist, create it if requested. */
if (flags & O_CREAT) {
ks = ksem_alloc(td->td_ucred, mode, value);
if (ks == NULL)
error = ENFILE;
else {
ksem_insert(path, fnv, ks);
path = NULL;
}
} else
error = ENOENT;
} else {
/*
* Object already exists, obtain a new
* reference if requested and permitted.
*/
if ((flags & (O_CREAT | O_EXCL)) ==
(O_CREAT | O_EXCL))
error = EEXIST;
else {
#ifdef MAC
error = mac_posixsem_check_open(td->td_ucred,
ks);
if (error == 0)
#endif
error = ksem_access(ks, td->td_ucred);
}
if (error == 0)
ksem_hold(ks);
#ifdef INVARIANTS
else
ks = NULL;
#endif
}
sx_xunlock(&ksem_dict_lock);
if (path)
free(path, M_KSEM);
}
if (error) {
KASSERT(ks == NULL, ("ksem_create error with a ksem"));
fdclose(fdp, fp, fd, td);
fdrop(fp, td);
return (error);
}
KASSERT(ks != NULL, ("ksem_create w/o a ksem"));
finit(fp, FREAD | FWRITE, DTYPE_SEM, ks, &ksem_ops);
fdrop(fp, td);
return (0);
}
static int
ksem_get(struct thread *td, semid_t id, cap_rights_t *rightsp,
struct file **fpp)
{
struct ksem *ks;
struct file *fp;
int error;
error = fget(td, id, rightsp, &fp);
if (error)
return (EINVAL);
if (fp->f_type != DTYPE_SEM) {
fdrop(fp, td);
return (EINVAL);
}
ks = fp->f_data;
if (ks->ks_flags & KS_DEAD) {
fdrop(fp, td);
return (EINVAL);
}
*fpp = fp;
return (0);
}
/* System calls. */
#ifndef _SYS_SYSPROTO_H_
struct ksem_init_args {
unsigned int value;
semid_t *idp;
};
#endif
int
sys_ksem_init(struct thread *td, struct ksem_init_args *uap)
{
return (ksem_create(td, NULL, uap->idp, S_IRWXU | S_IRWXG, uap->value,
0, 0));
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_open_args {
char *name;
int oflag;
mode_t mode;
unsigned int value;
semid_t *idp;
};
#endif
int
sys_ksem_open(struct thread *td, struct ksem_open_args *uap)
{
DP((">>> ksem_open start, pid=%d\n", (int)td->td_proc->p_pid));
if ((uap->oflag & ~(O_CREAT | O_EXCL)) != 0)
return (EINVAL);
return (ksem_create(td, uap->name, uap->idp, uap->mode, uap->value,
uap->oflag, 0));
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_unlink_args {
char *name;
};
#endif
int
sys_ksem_unlink(struct thread *td, struct ksem_unlink_args *uap)
{
char *path;
Fnv32_t fnv;
int error;
path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
error = copyinstr(uap->name, path, MAXPATHLEN, NULL);
if (error) {
free(path, M_TEMP);
return (error);
}
fnv = fnv_32_str(path, FNV1_32_INIT);
sx_xlock(&ksem_dict_lock);
error = ksem_remove(path, fnv, td->td_ucred);
sx_xunlock(&ksem_dict_lock);
free(path, M_TEMP);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_close_args {
semid_t id;
};
#endif
int
sys_ksem_close(struct thread *td, struct ksem_close_args *uap)
{
struct ksem *ks;
struct file *fp;
int error;
/* No capability rights required to close a semaphore. */
error = ksem_get(td, uap->id, 0, &fp);
if (error)
return (error);
ks = fp->f_data;
if (ks->ks_flags & KS_ANONYMOUS) {
fdrop(fp, td);
return (EINVAL);
}
error = kern_close(td, uap->id);
fdrop(fp, td);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_post_args {
semid_t id;
};
#endif
int
sys_ksem_post(struct thread *td, struct ksem_post_args *uap)
{
cap_rights_t rights;
struct file *fp;
struct ksem *ks;
int error;
error = ksem_get(td, uap->id,
cap_rights_init(&rights, CAP_SEM_POST), &fp);
if (error)
return (error);
ks = fp->f_data;
mtx_lock(&sem_lock);
#ifdef MAC
error = mac_posixsem_check_post(td->td_ucred, fp->f_cred, ks);
if (error)
goto err;
#endif
if (ks->ks_value == SEM_VALUE_MAX) {
error = EOVERFLOW;
goto err;
}
++ks->ks_value;
if (ks->ks_waiters > 0)
cv_signal(&ks->ks_cv);
error = 0;
vfs_timestamp(&ks->ks_ctime);
err:
mtx_unlock(&sem_lock);
fdrop(fp, td);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_wait_args {
semid_t id;
};
#endif
int
sys_ksem_wait(struct thread *td, struct ksem_wait_args *uap)
{
return (kern_sem_wait(td, uap->id, 0, NULL));
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_timedwait_args {
semid_t id;
const struct timespec *abstime;
};
#endif
int
sys_ksem_timedwait(struct thread *td, struct ksem_timedwait_args *uap)
{
struct timespec abstime;
struct timespec *ts;
int error;
/*
* We allow a null timespec (wait forever).
*/
if (uap->abstime == NULL)
ts = NULL;
else {
error = copyin(uap->abstime, &abstime, sizeof(abstime));
if (error != 0)
return (error);
if (abstime.tv_nsec >= 1000000000 || abstime.tv_nsec < 0)
return (EINVAL);
ts = &abstime;
}
return (kern_sem_wait(td, uap->id, 0, ts));
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_trywait_args {
semid_t id;
};
#endif
int
sys_ksem_trywait(struct thread *td, struct ksem_trywait_args *uap)
{
return (kern_sem_wait(td, uap->id, 1, NULL));
}
static int
kern_sem_wait(struct thread *td, semid_t id, int tryflag,
struct timespec *abstime)
{
struct timespec ts1, ts2;
struct timeval tv;
cap_rights_t rights;
struct file *fp;
struct ksem *ks;
int error;
DP((">>> kern_sem_wait entered! pid=%d\n", (int)td->td_proc->p_pid));
error = ksem_get(td, id, cap_rights_init(&rights, CAP_SEM_WAIT), &fp);
if (error)
return (error);
ks = fp->f_data;
mtx_lock(&sem_lock);
DP((">>> kern_sem_wait critical section entered! pid=%d\n",
(int)td->td_proc->p_pid));
#ifdef MAC
error = mac_posixsem_check_wait(td->td_ucred, fp->f_cred, ks);
if (error) {
DP(("kern_sem_wait mac failed\n"));
goto err;
}
#endif
DP(("kern_sem_wait value = %d, tryflag %d\n", ks->ks_value, tryflag));
vfs_timestamp(&ks->ks_atime);
while (ks->ks_value == 0) {
ks->ks_waiters++;
if (tryflag != 0)
error = EAGAIN;
else if (abstime == NULL)
error = cv_wait_sig(&ks->ks_cv, &sem_lock);
else {
for (;;) {
ts1 = *abstime;
getnanotime(&ts2);
timespecsub(&ts1, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts1);
if (tv.tv_sec < 0) {
error = ETIMEDOUT;
break;
}
error = cv_timedwait_sig(&ks->ks_cv,
&sem_lock, tvtohz(&tv));
if (error != EWOULDBLOCK)
break;
}
}
ks->ks_waiters--;
if (error)
goto err;
}
ks->ks_value--;
DP(("kern_sem_wait value post-decrement = %d\n", ks->ks_value));
error = 0;
err:
mtx_unlock(&sem_lock);
fdrop(fp, td);
DP(("<<< kern_sem_wait leaving, pid=%d, error = %d\n",
(int)td->td_proc->p_pid, error));
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_getvalue_args {
semid_t id;
int *val;
};
#endif
int
sys_ksem_getvalue(struct thread *td, struct ksem_getvalue_args *uap)
{
cap_rights_t rights;
struct file *fp;
struct ksem *ks;
int error, val;
error = ksem_get(td, uap->id,
cap_rights_init(&rights, CAP_SEM_GETVALUE), &fp);
if (error)
return (error);
ks = fp->f_data;
mtx_lock(&sem_lock);
#ifdef MAC
error = mac_posixsem_check_getvalue(td->td_ucred, fp->f_cred, ks);
if (error) {
mtx_unlock(&sem_lock);
fdrop(fp, td);
return (error);
}
#endif
val = ks->ks_value;
vfs_timestamp(&ks->ks_atime);
mtx_unlock(&sem_lock);
fdrop(fp, td);
error = copyout(&val, uap->val, sizeof(val));
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct ksem_destroy_args {
semid_t id;
};
#endif
int
sys_ksem_destroy(struct thread *td, struct ksem_destroy_args *uap)
{
struct file *fp;
struct ksem *ks;
int error;
/* No capability rights required to close a semaphore. */
error = ksem_get(td, uap->id, 0, &fp);
if (error)
return (error);
ks = fp->f_data;
if (!(ks->ks_flags & KS_ANONYMOUS)) {
fdrop(fp, td);
return (EINVAL);
}
mtx_lock(&sem_lock);
if (ks->ks_waiters != 0) {
mtx_unlock(&sem_lock);
error = EBUSY;
goto err;
}
ks->ks_flags |= KS_DEAD;
mtx_unlock(&sem_lock);
error = kern_close(td, uap->id);
err:
fdrop(fp, td);
return (error);
}
static struct syscall_helper_data ksem_syscalls[] = {
SYSCALL_INIT_HELPER(ksem_init),
SYSCALL_INIT_HELPER(ksem_open),
SYSCALL_INIT_HELPER(ksem_unlink),
SYSCALL_INIT_HELPER(ksem_close),
SYSCALL_INIT_HELPER(ksem_post),
SYSCALL_INIT_HELPER(ksem_wait),
SYSCALL_INIT_HELPER(ksem_timedwait),
SYSCALL_INIT_HELPER(ksem_trywait),
SYSCALL_INIT_HELPER(ksem_getvalue),
SYSCALL_INIT_HELPER(ksem_destroy),
SYSCALL_INIT_LAST
};
#ifdef COMPAT_FREEBSD32
#include <compat/freebsd32/freebsd32.h>
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_signal.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_util.h>
int
freebsd32_ksem_init(struct thread *td, struct freebsd32_ksem_init_args *uap)
{
return (ksem_create(td, NULL, uap->idp, S_IRWXU | S_IRWXG, uap->value,
0, 1));
}
int
freebsd32_ksem_open(struct thread *td, struct freebsd32_ksem_open_args *uap)
{
if ((uap->oflag & ~(O_CREAT | O_EXCL)) != 0)
return (EINVAL);
return (ksem_create(td, uap->name, uap->idp, uap->mode, uap->value,
uap->oflag, 1));
}
int
freebsd32_ksem_timedwait(struct thread *td,
struct freebsd32_ksem_timedwait_args *uap)
{
struct timespec32 abstime32;
struct timespec *ts, abstime;
int error;
/*
* We allow a null timespec (wait forever).
*/
if (uap->abstime == NULL)
ts = NULL;
else {
error = copyin(uap->abstime, &abstime32, sizeof(abstime32));
if (error != 0)
return (error);
CP(abstime32, abstime, tv_sec);
CP(abstime32, abstime, tv_nsec);
if (abstime.tv_nsec >= 1000000000 || abstime.tv_nsec < 0)
return (EINVAL);
ts = &abstime;
}
return (kern_sem_wait(td, uap->id, 0, ts));
}
static struct syscall_helper_data ksem32_syscalls[] = {
SYSCALL32_INIT_HELPER(freebsd32_ksem_init),
SYSCALL32_INIT_HELPER(freebsd32_ksem_open),
SYSCALL32_INIT_HELPER_COMPAT(ksem_unlink),
SYSCALL32_INIT_HELPER_COMPAT(ksem_close),
SYSCALL32_INIT_HELPER_COMPAT(ksem_post),
SYSCALL32_INIT_HELPER_COMPAT(ksem_wait),
SYSCALL32_INIT_HELPER(freebsd32_ksem_timedwait),
SYSCALL32_INIT_HELPER_COMPAT(ksem_trywait),
SYSCALL32_INIT_HELPER_COMPAT(ksem_getvalue),
SYSCALL32_INIT_HELPER_COMPAT(ksem_destroy),
SYSCALL_INIT_LAST
};
#endif
static int
ksem_module_init(void)
{
int error;
mtx_init(&sem_lock, "sem", NULL, MTX_DEF);
mtx_init(&ksem_count_lock, "ksem count", NULL, MTX_DEF);
sx_init(&ksem_dict_lock, "ksem dictionary");
ksem_dictionary = hashinit(1024, M_KSEM, &ksem_hash);
p31b_setcfg(CTL_P1003_1B_SEMAPHORES, 200112L);
p31b_setcfg(CTL_P1003_1B_SEM_NSEMS_MAX, SEM_MAX);
p31b_setcfg(CTL_P1003_1B_SEM_VALUE_MAX, SEM_VALUE_MAX);
error = syscall_helper_register(ksem_syscalls, SY_THR_STATIC_KLD);
if (error)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(ksem32_syscalls, SY_THR_STATIC_KLD);
if (error)
return (error);
#endif
return (0);
}
static void
ksem_module_destroy(void)
{
#ifdef COMPAT_FREEBSD32
syscall32_helper_unregister(ksem32_syscalls);
#endif
syscall_helper_unregister(ksem_syscalls);
p31b_setcfg(CTL_P1003_1B_SEMAPHORES, 0);
hashdestroy(ksem_dictionary, M_KSEM, ksem_hash);
sx_destroy(&ksem_dict_lock);
mtx_destroy(&ksem_count_lock);
mtx_destroy(&sem_lock);
p31b_unsetcfg(CTL_P1003_1B_SEM_VALUE_MAX);
p31b_unsetcfg(CTL_P1003_1B_SEM_NSEMS_MAX);
}
static int
sem_modload(struct module *module, int cmd, void *arg)
{
int error = 0;
switch (cmd) {
case MOD_LOAD:
error = ksem_module_init();
if (error)
ksem_module_destroy();
break;
case MOD_UNLOAD:
mtx_lock(&ksem_count_lock);
if (nsems != 0) {
error = EOPNOTSUPP;
mtx_unlock(&ksem_count_lock);
break;
}
ksem_dead = 1;
mtx_unlock(&ksem_count_lock);
ksem_module_destroy();
break;
case MOD_SHUTDOWN:
break;
default:
error = EINVAL;
break;
}
return (error);
}
static moduledata_t sem_mod = {
"sem",
&sem_modload,
NULL
};
DECLARE_MODULE(sem, sem_mod, SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
MODULE_VERSION(sem, 1);
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