vitalif
/
f-stack
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
f-stack/freebsd/kern/uipc_sem.c

1095 lines
25 KiB
C
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/jail.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)
{
const char *path, *pr_path;
struct ksem *ks;
size_t pr_pathlen;
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) {
path = ks->ks_path;
pr_path = curthread->td_ucred->cr_prison->pr_path;
if (strcmp(pr_path, "/") != 0) {
/* Return the jail-rooted pathname. */
pr_pathlen = strlen(pr_path);
if (strncmp(path, pr_path, pr_pathlen) == 0 &&
path[pr_pathlen] == '/')
path += pr_pathlen;
}
strlcpy(kif->kf_path, 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;
const char *pr_path;
size_t pr_pathlen;
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(td, fp, fd);
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);
pr_path = td->td_ucred->cr_prison->pr_path;
/* Construct a full pathname for jailed callers. */
pr_pathlen = strcmp(pr_path, "/") == 0 ? 0
: strlcpy(path, pr_path, MAXPATHLEN);
error = copyinstr(name, path + pr_pathlen,
MAXPATHLEN - pr_pathlen, NULL);
/* Require paths to start with a '/' character. */
if (error == 0 && path[pr_pathlen] != '/')
error = EINVAL;
if (error) {
fdclose(td, fp, fd);
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(td, fp, fd);
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;
const char *pr_path;
size_t pr_pathlen;
Fnv32_t fnv;
int error;
path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
pr_path = td->td_ucred->cr_prison->pr_path;
pr_pathlen = strcmp(pr_path, "/") == 0 ? 0
: strlcpy(path, pr_path, MAXPATHLEN);
error = copyinstr(uap->name, path + pr_pathlen, MAXPATHLEN - pr_pathlen,
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)
{
cap_rights_t rights;
struct ksem *ks;
struct file *fp;
int error;
/* No capability rights required to close a semaphore. */
error = ksem_get(td, uap->id, cap_rights_init(&rights), &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)
{
cap_rights_t rights;
struct file *fp;
struct ksem *ks;
int error;
/* No capability rights required to close a semaphore. */
error = ksem_get(td, uap->id, cap_rights_init(&rights), &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);
Reference in New Issue View Git Blame Copy Permalink