diff options
Diffstat (limited to 'sys/kern/uipc_sem.c')
| -rw-r--r-- | sys/kern/uipc_sem.c | 1091 |
1 files changed, 1091 insertions, 0 deletions
diff --git a/sys/kern/uipc_sem.c b/sys/kern/uipc_sem.c new file mode 100644 index 0000000..c219844 --- /dev/null +++ b/sys/kern/uipc_sem.c @@ -0,0 +1,1091 @@ +/*- + * 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/capability.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/vnode.h> + +#include <security/mac/mac_framework.h> + +FEATURE(p1003_1b_semaphores, "POSIX P1003.1B semaphores support"); +/* + * TODO + * + * - Resource limits? + * - Update fstat(1) + * - 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 rights, + 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_rdwr_t ksem_read; +static fo_rdwr_t ksem_write; +static fo_truncate_t ksem_truncate; +static fo_ioctl_t ksem_ioctl; +static fo_poll_t ksem_poll; +static fo_kqfilter_t ksem_kqfilter; +static fo_stat_t ksem_stat; +static fo_close_t ksem_closef; +static fo_chmod_t ksem_chmod; +static fo_chown_t ksem_chown; + +/* File descriptor operations. */ +static struct fileops ksem_ops = { + .fo_read = ksem_read, + .fo_write = ksem_write, + .fo_truncate = ksem_truncate, + .fo_ioctl = ksem_ioctl, + .fo_poll = ksem_poll, + .fo_kqfilter = ksem_kqfilter, + .fo_stat = ksem_stat, + .fo_close = ksem_closef, + .fo_chmod = ksem_chmod, + .fo_chown = ksem_chown, + .fo_flags = DFLAG_PASSABLE +}; + +FEATURE(posix_sem, "POSIX semaphores"); + +static int +ksem_read(struct file *fp, struct uio *uio, struct ucred *active_cred, + int flags, struct thread *td) +{ + + return (EOPNOTSUPP); +} + +static int +ksem_write(struct file *fp, struct uio *uio, struct ucred *active_cred, + int flags, struct thread *td) +{ + + return (EOPNOTSUPP); +} + +static int +ksem_truncate(struct file *fp, off_t length, struct ucred *active_cred, + struct thread *td) +{ + + return (EINVAL); +} + +static int +ksem_ioctl(struct file *fp, u_long com, void *data, + struct ucred *active_cred, struct thread *td) +{ + + return (EOPNOTSUPP); +} + +static int +ksem_poll(struct file *fp, int events, struct ucred *active_cred, + struct thread *td) +{ + + return (EOPNOTSUPP); +} + +static int +ksem_kqfilter(struct file *fp, struct knote *kn) +{ + + return (EOPNOTSUPP); +} + +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); +} + +/* + * 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); + 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); + 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, 0); + 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); + + FILEDESC_XLOCK(fdp); + if (fdp->fd_ofiles[fd] == fp) + fdp->fd_ofileflags[fd] |= UF_EXCLOSE; + FILEDESC_XUNLOCK(fdp); + fdrop(fp, td); + + return (0); +} + +static int +ksem_get(struct thread *td, semid_t id, cap_rights_t rights, struct file **fpp) +{ + struct ksem *ks; + struct file *fp; + int error; + + error = fget(td, id, rights, &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) +{ + struct file *fp; + struct ksem *ks; + int error; + + error = ksem_get(td, uap->id, 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; + 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_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) +{ + struct file *fp; + struct ksem *ks; + int error, val; + + error = ksem_get(td, uap->id, 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); + if (error) + return (error); +#ifdef COMPAT_FREEBSD32 + error = syscall32_helper_register(ksem32_syscalls); + 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); |
