freebsd-dev/sys/kern/sys_generic.c
Robert Watson 51d1f69069 Audit file-descriptor arguments to I/O system calls such as
read(2), write(2), dup(2), and mmap(2).  This auditing is not
required by the Common Criteria (and hence was not being
performed), but is valuable in both contemporary live analysis
and forensic use cases.

MFC after:	3 days
Sponsored by:	DARPA, AFRL
2016-07-10 08:04:02 +00:00

1952 lines
42 KiB
C

/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)sys_generic.c 8.5 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_capsicum.h"
#include "opt_compat.h"
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/capsicum.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/lock.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/socketvar.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/poll.h>
#include <sys/resourcevar.h>
#include <sys/selinfo.h>
#include <sys/sleepqueue.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/vnode.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/condvar.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <security/audit/audit.h>
/*
* The following macro defines how many bytes will be allocated from
* the stack instead of memory allocated when passing the IOCTL data
* structures from userspace and to the kernel. Some IOCTLs having
* small data structures are used very frequently and this small
* buffer on the stack gives a significant speedup improvement for
* those requests. The value of this define should be greater or equal
* to 64 bytes and should also be power of two. The data structure is
* currently hard-aligned to a 8-byte boundary on the stack. This
* should currently be sufficient for all supported platforms.
*/
#define SYS_IOCTL_SMALL_SIZE 128 /* bytes */
#define SYS_IOCTL_SMALL_ALIGN 8 /* bytes */
#ifdef __LP64__
static int iosize_max_clamp = 0;
SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
&iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
static int devfs_iosize_max_clamp = 1;
SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
&devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
#endif
/*
* Assert that the return value of read(2) and write(2) syscalls fits
* into a register. If not, an architecture will need to provide the
* usermode wrappers to reconstruct the result.
*/
CTASSERT(sizeof(register_t) >= sizeof(size_t));
static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
MALLOC_DEFINE(M_IOV, "iov", "large iov's");
static int pollout(struct thread *, struct pollfd *, struct pollfd *,
u_int);
static int pollscan(struct thread *, struct pollfd *, u_int);
static int pollrescan(struct thread *);
static int selscan(struct thread *, fd_mask **, fd_mask **, int);
static int selrescan(struct thread *, fd_mask **, fd_mask **);
static void selfdalloc(struct thread *, void *);
static void selfdfree(struct seltd *, struct selfd *);
static int dofileread(struct thread *, int, struct file *, struct uio *,
off_t, int);
static int dofilewrite(struct thread *, int, struct file *, struct uio *,
off_t, int);
static void doselwakeup(struct selinfo *, int);
static void seltdinit(struct thread *);
static int seltdwait(struct thread *, sbintime_t, sbintime_t);
static void seltdclear(struct thread *);
/*
* One seltd per-thread allocated on demand as needed.
*
* t - protected by st_mtx
* k - Only accessed by curthread or read-only
*/
struct seltd {
STAILQ_HEAD(, selfd) st_selq; /* (k) List of selfds. */
struct selfd *st_free1; /* (k) free fd for read set. */
struct selfd *st_free2; /* (k) free fd for write set. */
struct mtx st_mtx; /* Protects struct seltd */
struct cv st_wait; /* (t) Wait channel. */
int st_flags; /* (t) SELTD_ flags. */
};
#define SELTD_PENDING 0x0001 /* We have pending events. */
#define SELTD_RESCAN 0x0002 /* Doing a rescan. */
/*
* One selfd allocated per-thread per-file-descriptor.
* f - protected by sf_mtx
*/
struct selfd {
STAILQ_ENTRY(selfd) sf_link; /* (k) fds owned by this td. */
TAILQ_ENTRY(selfd) sf_threads; /* (f) fds on this selinfo. */
struct selinfo *sf_si; /* (f) selinfo when linked. */
struct mtx *sf_mtx; /* Pointer to selinfo mtx. */
struct seltd *sf_td; /* (k) owning seltd. */
void *sf_cookie; /* (k) fd or pollfd. */
u_int sf_refs;
};
static uma_zone_t selfd_zone;
static struct mtx_pool *mtxpool_select;
#ifdef __LP64__
size_t
devfs_iosize_max(void)
{
return (devfs_iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
INT_MAX : SSIZE_MAX);
}
size_t
iosize_max(void)
{
return (iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
INT_MAX : SSIZE_MAX);
}
#endif
#ifndef _SYS_SYSPROTO_H_
struct read_args {
int fd;
void *buf;
size_t nbyte;
};
#endif
int
sys_read(td, uap)
struct thread *td;
struct read_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > IOSIZE_MAX)
return (EINVAL);
aiov.iov_base = uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_readv(td, uap->fd, &auio);
return(error);
}
/*
* Positioned read system call
*/
#ifndef _SYS_SYSPROTO_H_
struct pread_args {
int fd;
void *buf;
size_t nbyte;
int pad;
off_t offset;
};
#endif
int
sys_pread(td, uap)
struct thread *td;
struct pread_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > IOSIZE_MAX)
return (EINVAL);
aiov.iov_base = uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_preadv(td, uap->fd, &auio, uap->offset);
return(error);
}
#if defined(COMPAT_FREEBSD6)
int
freebsd6_pread(td, uap)
struct thread *td;
struct freebsd6_pread_args *uap;
{
struct pread_args oargs;
oargs.fd = uap->fd;
oargs.buf = uap->buf;
oargs.nbyte = uap->nbyte;
oargs.offset = uap->offset;
return (sys_pread(td, &oargs));
}
#endif
/*
* Scatter read system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct readv_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
};
#endif
int
sys_readv(struct thread *td, struct readv_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_readv(td, uap->fd, auio);
free(auio, M_IOV);
return (error);
}
int
kern_readv(struct thread *td, int fd, struct uio *auio)
{
struct file *fp;
cap_rights_t rights;
int error;
error = fget_read(td, fd, cap_rights_init(&rights, CAP_READ), &fp);
if (error)
return (error);
error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
fdrop(fp, td);
return (error);
}
/*
* Scatter positioned read system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct preadv_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
off_t offset;
};
#endif
int
sys_preadv(struct thread *td, struct preadv_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_preadv(td, uap->fd, auio, uap->offset);
free(auio, M_IOV);
return (error);
}
int
kern_preadv(td, fd, auio, offset)
struct thread *td;
int fd;
struct uio *auio;
off_t offset;
{
struct file *fp;
cap_rights_t rights;
int error;
error = fget_read(td, fd, cap_rights_init(&rights, CAP_PREAD), &fp);
if (error)
return (error);
if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
error = ESPIPE;
else if (offset < 0 && fp->f_vnode->v_type != VCHR)
error = EINVAL;
else
error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
fdrop(fp, td);
return (error);
}
/*
* Common code for readv and preadv that reads data in
* from a file using the passed in uio, offset, and flags.
*/
static int
dofileread(td, fd, fp, auio, offset, flags)
struct thread *td;
int fd;
struct file *fp;
struct uio *auio;
off_t offset;
int flags;
{
ssize_t cnt;
int error;
#ifdef KTRACE
struct uio *ktruio = NULL;
#endif
AUDIT_ARG_FD(fd);
/* Finish zero length reads right here */
if (auio->uio_resid == 0) {
td->td_retval[0] = 0;
return(0);
}
auio->uio_rw = UIO_READ;
auio->uio_offset = offset;
auio->uio_td = td;
#ifdef KTRACE
if (KTRPOINT(td, KTR_GENIO))
ktruio = cloneuio(auio);
#endif
cnt = auio->uio_resid;
if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
if (auio->uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
}
cnt -= auio->uio_resid;
#ifdef KTRACE
if (ktruio != NULL) {
ktruio->uio_resid = cnt;
ktrgenio(fd, UIO_READ, ktruio, error);
}
#endif
td->td_retval[0] = cnt;
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct write_args {
int fd;
const void *buf;
size_t nbyte;
};
#endif
int
sys_write(td, uap)
struct thread *td;
struct write_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > IOSIZE_MAX)
return (EINVAL);
aiov.iov_base = (void *)(uintptr_t)uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_writev(td, uap->fd, &auio);
return(error);
}
/*
* Positioned write system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct pwrite_args {
int fd;
const void *buf;
size_t nbyte;
int pad;
off_t offset;
};
#endif
int
sys_pwrite(td, uap)
struct thread *td;
struct pwrite_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > IOSIZE_MAX)
return (EINVAL);
aiov.iov_base = (void *)(uintptr_t)uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_pwritev(td, uap->fd, &auio, uap->offset);
return(error);
}
#if defined(COMPAT_FREEBSD6)
int
freebsd6_pwrite(td, uap)
struct thread *td;
struct freebsd6_pwrite_args *uap;
{
struct pwrite_args oargs;
oargs.fd = uap->fd;
oargs.buf = uap->buf;
oargs.nbyte = uap->nbyte;
oargs.offset = uap->offset;
return (sys_pwrite(td, &oargs));
}
#endif
/*
* Gather write system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct writev_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
};
#endif
int
sys_writev(struct thread *td, struct writev_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_writev(td, uap->fd, auio);
free(auio, M_IOV);
return (error);
}
int
kern_writev(struct thread *td, int fd, struct uio *auio)
{
struct file *fp;
cap_rights_t rights;
int error;
error = fget_write(td, fd, cap_rights_init(&rights, CAP_WRITE), &fp);
if (error)
return (error);
error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
fdrop(fp, td);
return (error);
}
/*
* Gather positioned write system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct pwritev_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
off_t offset;
};
#endif
int
sys_pwritev(struct thread *td, struct pwritev_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_pwritev(td, uap->fd, auio, uap->offset);
free(auio, M_IOV);
return (error);
}
int
kern_pwritev(td, fd, auio, offset)
struct thread *td;
struct uio *auio;
int fd;
off_t offset;
{
struct file *fp;
cap_rights_t rights;
int error;
error = fget_write(td, fd, cap_rights_init(&rights, CAP_PWRITE), &fp);
if (error)
return (error);
if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
error = ESPIPE;
else if (offset < 0 && fp->f_vnode->v_type != VCHR)
error = EINVAL;
else
error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
fdrop(fp, td);
return (error);
}
/*
* Common code for writev and pwritev that writes data to
* a file using the passed in uio, offset, and flags.
*/
static int
dofilewrite(td, fd, fp, auio, offset, flags)
struct thread *td;
int fd;
struct file *fp;
struct uio *auio;
off_t offset;
int flags;
{
ssize_t cnt;
int error;
#ifdef KTRACE
struct uio *ktruio = NULL;
#endif
AUDIT_ARG_FD(fd);
auio->uio_rw = UIO_WRITE;
auio->uio_td = td;
auio->uio_offset = offset;
#ifdef KTRACE
if (KTRPOINT(td, KTR_GENIO))
ktruio = cloneuio(auio);
#endif
cnt = auio->uio_resid;
if (fp->f_type == DTYPE_VNODE &&
(fp->f_vnread_flags & FDEVFS_VNODE) == 0)
bwillwrite();
if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
if (auio->uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
/* Socket layer is responsible for issuing SIGPIPE. */
if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
PROC_LOCK(td->td_proc);
tdsignal(td, SIGPIPE);
PROC_UNLOCK(td->td_proc);
}
}
cnt -= auio->uio_resid;
#ifdef KTRACE
if (ktruio != NULL) {
ktruio->uio_resid = cnt;
ktrgenio(fd, UIO_WRITE, ktruio, error);
}
#endif
td->td_retval[0] = cnt;
return (error);
}
/*
* Truncate a file given a file descriptor.
*
* Can't use fget_write() here, since must return EINVAL and not EBADF if the
* descriptor isn't writable.
*/
int
kern_ftruncate(td, fd, length)
struct thread *td;
int fd;
off_t length;
{
struct file *fp;
cap_rights_t rights;
int error;
AUDIT_ARG_FD(fd);
if (length < 0)
return (EINVAL);
error = fget(td, fd, cap_rights_init(&rights, CAP_FTRUNCATE), &fp);
if (error)
return (error);
AUDIT_ARG_FILE(td->td_proc, fp);
if (!(fp->f_flag & FWRITE)) {
fdrop(fp, td);
return (EINVAL);
}
error = fo_truncate(fp, length, td->td_ucred, td);
fdrop(fp, td);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct ftruncate_args {
int fd;
int pad;
off_t length;
};
#endif
int
sys_ftruncate(td, uap)
struct thread *td;
struct ftruncate_args *uap;
{
return (kern_ftruncate(td, uap->fd, uap->length));
}
#if defined(COMPAT_43)
#ifndef _SYS_SYSPROTO_H_
struct oftruncate_args {
int fd;
long length;
};
#endif
int
oftruncate(td, uap)
struct thread *td;
struct oftruncate_args *uap;
{
return (kern_ftruncate(td, uap->fd, uap->length));
}
#endif /* COMPAT_43 */
#ifndef _SYS_SYSPROTO_H_
struct ioctl_args {
int fd;
u_long com;
caddr_t data;
};
#endif
/* ARGSUSED */
int
sys_ioctl(struct thread *td, struct ioctl_args *uap)
{
u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN);
u_long com;
int arg, error;
u_int size;
caddr_t data;
if (uap->com > 0xffffffff) {
printf(
"WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
td->td_proc->p_pid, td->td_name, uap->com);
uap->com &= 0xffffffff;
}
com = uap->com;
/*
* Interpret high order word to find amount of data to be
* copied to/from the user's address space.
*/
size = IOCPARM_LEN(com);
if ((size > IOCPARM_MAX) ||
((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) ||
#if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
((com & IOC_OUT) && size == 0) ||
#else
((com & (IOC_IN | IOC_OUT)) && size == 0) ||
#endif
((com & IOC_VOID) && size > 0 && size != sizeof(int)))
return (ENOTTY);
if (size > 0) {
if (com & IOC_VOID) {
/* Integer argument. */
arg = (intptr_t)uap->data;
data = (void *)&arg;
size = 0;
} else {
if (size > SYS_IOCTL_SMALL_SIZE)
data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
else
data = smalldata;
}
} else
data = (void *)&uap->data;
if (com & IOC_IN) {
error = copyin(uap->data, data, (u_int)size);
if (error != 0)
goto out;
} else if (com & IOC_OUT) {
/*
* Zero the buffer so the user always
* gets back something deterministic.
*/
bzero(data, size);
}
error = kern_ioctl(td, uap->fd, com, data);
if (error == 0 && (com & IOC_OUT))
error = copyout(data, uap->data, (u_int)size);
out:
if (size > SYS_IOCTL_SMALL_SIZE)
free(data, M_IOCTLOPS);
return (error);
}
int
kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
{
struct file *fp;
struct filedesc *fdp;
#ifndef CAPABILITIES
cap_rights_t rights;
#endif
int error, tmp, locked;
AUDIT_ARG_FD(fd);
AUDIT_ARG_CMD(com);
fdp = td->td_proc->p_fd;
switch (com) {
case FIONCLEX:
case FIOCLEX:
FILEDESC_XLOCK(fdp);
locked = LA_XLOCKED;
break;
default:
#ifdef CAPABILITIES
FILEDESC_SLOCK(fdp);
locked = LA_SLOCKED;
#else
locked = LA_UNLOCKED;
#endif
break;
}
#ifdef CAPABILITIES
if ((fp = fget_locked(fdp, fd)) == NULL) {
error = EBADF;
goto out;
}
if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
fp = NULL; /* fhold() was not called yet */
goto out;
}
fhold(fp);
if (locked == LA_SLOCKED) {
FILEDESC_SUNLOCK(fdp);
locked = LA_UNLOCKED;
}
#else
error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
if (error != 0) {
fp = NULL;
goto out;
}
#endif
if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
error = EBADF;
goto out;
}
switch (com) {
case FIONCLEX:
fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
goto out;
case FIOCLEX:
fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
goto out;
case FIONBIO:
if ((tmp = *(int *)data))
atomic_set_int(&fp->f_flag, FNONBLOCK);
else
atomic_clear_int(&fp->f_flag, FNONBLOCK);
data = (void *)&tmp;
break;
case FIOASYNC:
if ((tmp = *(int *)data))
atomic_set_int(&fp->f_flag, FASYNC);
else
atomic_clear_int(&fp->f_flag, FASYNC);
data = (void *)&tmp;
break;
}
error = fo_ioctl(fp, com, data, td->td_ucred, td);
out:
switch (locked) {
case LA_XLOCKED:
FILEDESC_XUNLOCK(fdp);
break;
#ifdef CAPABILITIES
case LA_SLOCKED:
FILEDESC_SUNLOCK(fdp);
break;
#endif
default:
FILEDESC_UNLOCK_ASSERT(fdp);
break;
}
if (fp != NULL)
fdrop(fp, td);
return (error);
}
int
poll_no_poll(int events)
{
/*
* Return true for read/write. If the user asked for something
* special, return POLLNVAL, so that clients have a way of
* determining reliably whether or not the extended
* functionality is present without hard-coding knowledge
* of specific filesystem implementations.
*/
if (events & ~POLLSTANDARD)
return (POLLNVAL);
return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}
int
sys_pselect(struct thread *td, struct pselect_args *uap)
{
struct timespec ts;
struct timeval tv, *tvp;
sigset_t set, *uset;
int error;
if (uap->ts != NULL) {
error = copyin(uap->ts, &ts, sizeof(ts));
if (error != 0)
return (error);
TIMESPEC_TO_TIMEVAL(&tv, &ts);
tvp = &tv;
} else
tvp = NULL;
if (uap->sm != NULL) {
error = copyin(uap->sm, &set, sizeof(set));
if (error != 0)
return (error);
uset = &set;
} else
uset = NULL;
return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
uset, NFDBITS));
}
int
kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
{
int error;
if (uset != NULL) {
error = kern_sigprocmask(td, SIG_SETMASK, uset,
&td->td_oldsigmask, 0);
if (error != 0)
return (error);
td->td_pflags |= TDP_OLDMASK;
/*
* Make sure that ast() is called on return to
* usermode and TDP_OLDMASK is cleared, restoring old
* sigmask.
*/
thread_lock(td);
td->td_flags |= TDF_ASTPENDING;
thread_unlock(td);
}
error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct select_args {
int nd;
fd_set *in, *ou, *ex;
struct timeval *tv;
};
#endif
int
sys_select(struct thread *td, struct select_args *uap)
{
struct timeval tv, *tvp;
int error;
if (uap->tv != NULL) {
error = copyin(uap->tv, &tv, sizeof(tv));
if (error)
return (error);
tvp = &tv;
} else
tvp = NULL;
return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
NFDBITS));
}
/*
* In the unlikely case when user specified n greater then the last
* open file descriptor, check that no bits are set after the last
* valid fd. We must return EBADF if any is set.
*
* There are applications that rely on the behaviour.
*
* nd is fd_lastfile + 1.
*/
static int
select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
{
char *addr, *oaddr;
int b, i, res;
uint8_t bits;
if (nd >= ndu || fd_in == NULL)
return (0);
oaddr = NULL;
bits = 0; /* silence gcc */
for (i = nd; i < ndu; i++) {
b = i / NBBY;
#if BYTE_ORDER == LITTLE_ENDIAN
addr = (char *)fd_in + b;
#else
addr = (char *)fd_in;
if (abi_nfdbits == NFDBITS) {
addr += rounddown(b, sizeof(fd_mask)) +
sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
} else {
addr += rounddown(b, sizeof(uint32_t)) +
sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
}
#endif
if (addr != oaddr) {
res = fubyte(addr);
if (res == -1)
return (EFAULT);
oaddr = addr;
bits = res;
}
if ((bits & (1 << (i % NBBY))) != 0)
return (EBADF);
}
return (0);
}
int
kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
{
struct filedesc *fdp;
/*
* The magic 2048 here is chosen to be just enough for FD_SETSIZE
* infds with the new FD_SETSIZE of 1024, and more than enough for
* FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
* of 256.
*/
fd_mask s_selbits[howmany(2048, NFDBITS)];
fd_mask *ibits[3], *obits[3], *selbits, *sbp;
struct timeval rtv;
sbintime_t asbt, precision, rsbt;
u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
int error, lf, ndu;
if (nd < 0)
return (EINVAL);
fdp = td->td_proc->p_fd;
ndu = nd;
lf = fdp->fd_lastfile;
if (nd > lf + 1)
nd = lf + 1;
error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
if (error != 0)
return (error);
error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
if (error != 0)
return (error);
error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
if (error != 0)
return (error);
/*
* Allocate just enough bits for the non-null fd_sets. Use the
* preallocated auto buffer if possible.
*/
nfdbits = roundup(nd, NFDBITS);
ncpbytes = nfdbits / NBBY;
ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
nbufbytes = 0;
if (fd_in != NULL)
nbufbytes += 2 * ncpbytes;
if (fd_ou != NULL)
nbufbytes += 2 * ncpbytes;
if (fd_ex != NULL)
nbufbytes += 2 * ncpbytes;
if (nbufbytes <= sizeof s_selbits)
selbits = &s_selbits[0];
else
selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
/*
* Assign pointers into the bit buffers and fetch the input bits.
* Put the output buffers together so that they can be bzeroed
* together.
*/
sbp = selbits;
#define getbits(name, x) \
do { \
if (name == NULL) { \
ibits[x] = NULL; \
obits[x] = NULL; \
} else { \
ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \
obits[x] = sbp; \
sbp += ncpbytes / sizeof *sbp; \
error = copyin(name, ibits[x], ncpubytes); \
if (error != 0) \
goto done; \
bzero((char *)ibits[x] + ncpubytes, \
ncpbytes - ncpubytes); \
} \
} while (0)
getbits(fd_in, 0);
getbits(fd_ou, 1);
getbits(fd_ex, 2);
#undef getbits
#if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
/*
* XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
* we are running under 32-bit emulation. This should be more
* generic.
*/
#define swizzle_fdset(bits) \
if (abi_nfdbits != NFDBITS && bits != NULL) { \
int i; \
for (i = 0; i < ncpbytes / sizeof *sbp; i++) \
bits[i] = (bits[i] >> 32) | (bits[i] << 32); \
}
#else
#define swizzle_fdset(bits)
#endif
/* Make sure the bit order makes it through an ABI transition */
swizzle_fdset(ibits[0]);
swizzle_fdset(ibits[1]);
swizzle_fdset(ibits[2]);
if (nbufbytes != 0)
bzero(selbits, nbufbytes / 2);
precision = 0;
if (tvp != NULL) {
rtv = *tvp;
if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
rtv.tv_usec >= 1000000) {
error = EINVAL;
goto done;
}
if (!timevalisset(&rtv))
asbt = 0;
else if (rtv.tv_sec <= INT32_MAX) {
rsbt = tvtosbt(rtv);
precision = rsbt;
precision >>= tc_precexp;
if (TIMESEL(&asbt, rsbt))
asbt += tc_tick_sbt;
if (asbt <= SBT_MAX - rsbt)
asbt += rsbt;
else
asbt = -1;
} else
asbt = -1;
} else
asbt = -1;
seltdinit(td);
/* Iterate until the timeout expires or descriptors become ready. */
for (;;) {
error = selscan(td, ibits, obits, nd);
if (error || td->td_retval[0] != 0)
break;
error = seltdwait(td, asbt, precision);
if (error)
break;
error = selrescan(td, ibits, obits);
if (error || td->td_retval[0] != 0)
break;
}
seltdclear(td);
done:
/* select is not restarted after signals... */
if (error == ERESTART)
error = EINTR;
if (error == EWOULDBLOCK)
error = 0;
/* swizzle bit order back, if necessary */
swizzle_fdset(obits[0]);
swizzle_fdset(obits[1]);
swizzle_fdset(obits[2]);
#undef swizzle_fdset
#define putbits(name, x) \
if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
error = error2;
if (error == 0) {
int error2;
putbits(fd_in, 0);
putbits(fd_ou, 1);
putbits(fd_ex, 2);
#undef putbits
}
if (selbits != &s_selbits[0])
free(selbits, M_SELECT);
return (error);
}
/*
* Convert a select bit set to poll flags.
*
* The backend always returns POLLHUP/POLLERR if appropriate and we
* return this as a set bit in any set.
*/
static int select_flags[3] = {
POLLRDNORM | POLLHUP | POLLERR,
POLLWRNORM | POLLHUP | POLLERR,
POLLRDBAND | POLLERR
};
/*
* Compute the fo_poll flags required for a fd given by the index and
* bit position in the fd_mask array.
*/
static __inline int
selflags(fd_mask **ibits, int idx, fd_mask bit)
{
int flags;
int msk;
flags = 0;
for (msk = 0; msk < 3; msk++) {
if (ibits[msk] == NULL)
continue;
if ((ibits[msk][idx] & bit) == 0)
continue;
flags |= select_flags[msk];
}
return (flags);
}
/*
* Set the appropriate output bits given a mask of fired events and the
* input bits originally requested.
*/
static __inline int
selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
{
int msk;
int n;
n = 0;
for (msk = 0; msk < 3; msk++) {
if ((events & select_flags[msk]) == 0)
continue;
if (ibits[msk] == NULL)
continue;
if ((ibits[msk][idx] & bit) == 0)
continue;
/*
* XXX Check for a duplicate set. This can occur because a
* socket calls selrecord() twice for each poll() call
* resulting in two selfds per real fd. selrescan() will
* call selsetbits twice as a result.
*/
if ((obits[msk][idx] & bit) != 0)
continue;
obits[msk][idx] |= bit;
n++;
}
return (n);
}
static __inline int
getselfd_cap(struct filedesc *fdp, int fd, struct file **fpp)
{
cap_rights_t rights;
cap_rights_init(&rights, CAP_EVENT);
return (fget_unlocked(fdp, fd, &rights, fpp, NULL));
}
/*
* Traverse the list of fds attached to this thread's seltd and check for
* completion.
*/
static int
selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
{
struct filedesc *fdp;
struct selinfo *si;
struct seltd *stp;
struct selfd *sfp;
struct selfd *sfn;
struct file *fp;
fd_mask bit;
int fd, ev, n, idx;
int error;
fdp = td->td_proc->p_fd;
stp = td->td_sel;
n = 0;
STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
fd = (int)(uintptr_t)sfp->sf_cookie;
si = sfp->sf_si;
selfdfree(stp, sfp);
/* If the selinfo wasn't cleared the event didn't fire. */
if (si != NULL)
continue;
error = getselfd_cap(fdp, fd, &fp);
if (error)
return (error);
idx = fd / NFDBITS;
bit = (fd_mask)1 << (fd % NFDBITS);
ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
fdrop(fp, td);
if (ev != 0)
n += selsetbits(ibits, obits, idx, bit, ev);
}
stp->st_flags = 0;
td->td_retval[0] = n;
return (0);
}
/*
* Perform the initial filedescriptor scan and register ourselves with
* each selinfo.
*/
static int
selscan(td, ibits, obits, nfd)
struct thread *td;
fd_mask **ibits, **obits;
int nfd;
{
struct filedesc *fdp;
struct file *fp;
fd_mask bit;
int ev, flags, end, fd;
int n, idx;
int error;
fdp = td->td_proc->p_fd;
n = 0;
for (idx = 0, fd = 0; fd < nfd; idx++) {
end = imin(fd + NFDBITS, nfd);
for (bit = 1; fd < end; bit <<= 1, fd++) {
/* Compute the list of events we're interested in. */
flags = selflags(ibits, idx, bit);
if (flags == 0)
continue;
error = getselfd_cap(fdp, fd, &fp);
if (error)
return (error);
selfdalloc(td, (void *)(uintptr_t)fd);
ev = fo_poll(fp, flags, td->td_ucred, td);
fdrop(fp, td);
if (ev != 0)
n += selsetbits(ibits, obits, idx, bit, ev);
}
}
td->td_retval[0] = n;
return (0);
}
int
sys_poll(struct thread *td, struct poll_args *uap)
{
struct timespec ts, *tsp;
if (uap->timeout != INFTIM) {
if (uap->timeout < 0)
return (EINVAL);
ts.tv_sec = uap->timeout / 1000;
ts.tv_nsec = (uap->timeout % 1000) * 1000000;
tsp = &ts;
} else
tsp = NULL;
return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
}
int
kern_poll(struct thread *td, struct pollfd *fds, u_int nfds,
struct timespec *tsp, sigset_t *uset)
{
struct pollfd *bits;
struct pollfd smallbits[32];
sbintime_t sbt, precision, tmp;
time_t over;
struct timespec ts;
int error;
size_t ni;
precision = 0;
if (tsp != NULL) {
if (tsp->tv_sec < 0)
return (EINVAL);
if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
return (EINVAL);
if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
sbt = 0;
else {
ts = *tsp;
if (ts.tv_sec > INT32_MAX / 2) {
over = ts.tv_sec - INT32_MAX / 2;
ts.tv_sec -= over;
} else
over = 0;
tmp = tstosbt(ts);
precision = tmp;
precision >>= tc_precexp;
if (TIMESEL(&sbt, tmp))
sbt += tc_tick_sbt;
sbt += tmp;
}
} else
sbt = -1;
if (nfds > maxfilesperproc && nfds > FD_SETSIZE)
return (EINVAL);
ni = nfds * sizeof(struct pollfd);
if (ni > sizeof(smallbits))
bits = malloc(ni, M_TEMP, M_WAITOK);
else
bits = smallbits;
error = copyin(fds, bits, ni);
if (error)
goto done;
if (uset != NULL) {
error = kern_sigprocmask(td, SIG_SETMASK, uset,
&td->td_oldsigmask, 0);
if (error)
goto done;
td->td_pflags |= TDP_OLDMASK;
/*
* Make sure that ast() is called on return to
* usermode and TDP_OLDMASK is cleared, restoring old
* sigmask.
*/
thread_lock(td);
td->td_flags |= TDF_ASTPENDING;
thread_unlock(td);
}
seltdinit(td);
/* Iterate until the timeout expires or descriptors become ready. */
for (;;) {
error = pollscan(td, bits, nfds);
if (error || td->td_retval[0] != 0)
break;
error = seltdwait(td, sbt, precision);
if (error)
break;
error = pollrescan(td);
if (error || td->td_retval[0] != 0)
break;
}
seltdclear(td);
done:
/* poll is not restarted after signals... */
if (error == ERESTART)
error = EINTR;
if (error == EWOULDBLOCK)
error = 0;
if (error == 0) {
error = pollout(td, bits, fds, nfds);
if (error)
goto out;
}
out:
if (ni > sizeof(smallbits))
free(bits, M_TEMP);
return (error);
}
int
sys_ppoll(struct thread *td, struct ppoll_args *uap)
{
struct timespec ts, *tsp;
sigset_t set, *ssp;
int error;
if (uap->ts != NULL) {
error = copyin(uap->ts, &ts, sizeof(ts));
if (error)
return (error);
tsp = &ts;
} else
tsp = NULL;
if (uap->set != NULL) {
error = copyin(uap->set, &set, sizeof(set));
if (error)
return (error);
ssp = &set;
} else
ssp = NULL;
/*
* fds is still a pointer to user space. kern_poll() will
* take care of copyin that array to the kernel space.
*/
return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
}
static int
pollrescan(struct thread *td)
{
struct seltd *stp;
struct selfd *sfp;
struct selfd *sfn;
struct selinfo *si;
struct filedesc *fdp;
struct file *fp;
struct pollfd *fd;
#ifdef CAPABILITIES
cap_rights_t rights;
#endif
int n;
n = 0;
fdp = td->td_proc->p_fd;
stp = td->td_sel;
FILEDESC_SLOCK(fdp);
STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
fd = (struct pollfd *)sfp->sf_cookie;
si = sfp->sf_si;
selfdfree(stp, sfp);
/* If the selinfo wasn't cleared the event didn't fire. */
if (si != NULL)
continue;
fp = fdp->fd_ofiles[fd->fd].fde_file;
#ifdef CAPABILITIES
if (fp == NULL ||
cap_check(cap_rights(fdp, fd->fd),
cap_rights_init(&rights, CAP_EVENT)) != 0)
#else
if (fp == NULL)
#endif
{
fd->revents = POLLNVAL;
n++;
continue;
}
/*
* Note: backend also returns POLLHUP and
* POLLERR if appropriate.
*/
fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
if (fd->revents != 0)
n++;
}
FILEDESC_SUNLOCK(fdp);
stp->st_flags = 0;
td->td_retval[0] = n;
return (0);
}
static int
pollout(td, fds, ufds, nfd)
struct thread *td;
struct pollfd *fds;
struct pollfd *ufds;
u_int nfd;
{
int error = 0;
u_int i = 0;
u_int n = 0;
for (i = 0; i < nfd; i++) {
error = copyout(&fds->revents, &ufds->revents,
sizeof(ufds->revents));
if (error)
return (error);
if (fds->revents != 0)
n++;
fds++;
ufds++;
}
td->td_retval[0] = n;
return (0);
}
static int
pollscan(td, fds, nfd)
struct thread *td;
struct pollfd *fds;
u_int nfd;
{
struct filedesc *fdp = td->td_proc->p_fd;
struct file *fp;
#ifdef CAPABILITIES
cap_rights_t rights;
#endif
int i, n = 0;
FILEDESC_SLOCK(fdp);
for (i = 0; i < nfd; i++, fds++) {
if (fds->fd > fdp->fd_lastfile) {
fds->revents = POLLNVAL;
n++;
} else if (fds->fd < 0) {
fds->revents = 0;
} else {
fp = fdp->fd_ofiles[fds->fd].fde_file;
#ifdef CAPABILITIES
if (fp == NULL ||
cap_check(cap_rights(fdp, fds->fd),
cap_rights_init(&rights, CAP_EVENT)) != 0)
#else
if (fp == NULL)
#endif
{
fds->revents = POLLNVAL;
n++;
} else {
/*
* Note: backend also returns POLLHUP and
* POLLERR if appropriate.
*/
selfdalloc(td, fds);
fds->revents = fo_poll(fp, fds->events,
td->td_ucred, td);
/*
* POSIX requires POLLOUT to be never
* set simultaneously with POLLHUP.
*/
if ((fds->revents & POLLHUP) != 0)
fds->revents &= ~POLLOUT;
if (fds->revents != 0)
n++;
}
}
}
FILEDESC_SUNLOCK(fdp);
td->td_retval[0] = n;
return (0);
}
/*
* OpenBSD poll system call.
*
* XXX this isn't quite a true representation.. OpenBSD uses select ops.
*/
#ifndef _SYS_SYSPROTO_H_
struct openbsd_poll_args {
struct pollfd *fds;
u_int nfds;
int timeout;
};
#endif
int
sys_openbsd_poll(td, uap)
register struct thread *td;
register struct openbsd_poll_args *uap;
{
return (sys_poll(td, (struct poll_args *)uap));
}
/*
* XXX This was created specifically to support netncp and netsmb. This
* allows the caller to specify a socket to wait for events on. It returns
* 0 if any events matched and an error otherwise. There is no way to
* determine which events fired.
*/
int
selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
{
struct timeval rtv;
sbintime_t asbt, precision, rsbt;
int error;
precision = 0; /* stupid gcc! */
if (tvp != NULL) {
rtv = *tvp;
if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
rtv.tv_usec >= 1000000)
return (EINVAL);
if (!timevalisset(&rtv))
asbt = 0;
else if (rtv.tv_sec <= INT32_MAX) {
rsbt = tvtosbt(rtv);
precision = rsbt;
precision >>= tc_precexp;
if (TIMESEL(&asbt, rsbt))
asbt += tc_tick_sbt;
if (asbt <= SBT_MAX - rsbt)
asbt += rsbt;
else
asbt = -1;
} else
asbt = -1;
} else
asbt = -1;
seltdinit(td);
/*
* Iterate until the timeout expires or the socket becomes ready.
*/
for (;;) {
selfdalloc(td, NULL);
error = sopoll(so, events, NULL, td);
/* error here is actually the ready events. */
if (error)
return (0);
error = seltdwait(td, asbt, precision);
if (error)
break;
}
seltdclear(td);
/* XXX Duplicates ncp/smb behavior. */
if (error == ERESTART)
error = 0;
return (error);
}
/*
* Preallocate two selfds associated with 'cookie'. Some fo_poll routines
* have two select sets, one for read and another for write.
*/
static void
selfdalloc(struct thread *td, void *cookie)
{
struct seltd *stp;
stp = td->td_sel;
if (stp->st_free1 == NULL)
stp->st_free1 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
stp->st_free1->sf_td = stp;
stp->st_free1->sf_cookie = cookie;
if (stp->st_free2 == NULL)
stp->st_free2 = uma_zalloc(selfd_zone, M_WAITOK|M_ZERO);
stp->st_free2->sf_td = stp;
stp->st_free2->sf_cookie = cookie;
}
static void
selfdfree(struct seltd *stp, struct selfd *sfp)
{
STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
if (sfp->sf_si != NULL) {
mtx_lock(sfp->sf_mtx);
if (sfp->sf_si != NULL) {
TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
refcount_release(&sfp->sf_refs);
}
mtx_unlock(sfp->sf_mtx);
}
if (refcount_release(&sfp->sf_refs))
uma_zfree(selfd_zone, sfp);
}
/* Drain the waiters tied to all the selfd belonging the specified selinfo. */
void
seldrain(sip)
struct selinfo *sip;
{
/*
* This feature is already provided by doselwakeup(), thus it is
* enough to go for it.
* Eventually, the context, should take care to avoid races
* between thread calling select()/poll() and file descriptor
* detaching, but, again, the races are just the same as
* selwakeup().
*/
doselwakeup(sip, -1);
}
/*
* Record a select request.
*/
void
selrecord(selector, sip)
struct thread *selector;
struct selinfo *sip;
{
struct selfd *sfp;
struct seltd *stp;
struct mtx *mtxp;
stp = selector->td_sel;
/*
* Don't record when doing a rescan.
*/
if (stp->st_flags & SELTD_RESCAN)
return;
/*
* Grab one of the preallocated descriptors.
*/
sfp = NULL;
if ((sfp = stp->st_free1) != NULL)
stp->st_free1 = NULL;
else if ((sfp = stp->st_free2) != NULL)
stp->st_free2 = NULL;
else
panic("selrecord: No free selfd on selq");
mtxp = sip->si_mtx;
if (mtxp == NULL)
mtxp = mtx_pool_find(mtxpool_select, sip);
/*
* Initialize the sfp and queue it in the thread.
*/
sfp->sf_si = sip;
sfp->sf_mtx = mtxp;
refcount_init(&sfp->sf_refs, 2);
STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
/*
* Now that we've locked the sip, check for initialization.
*/
mtx_lock(mtxp);
if (sip->si_mtx == NULL) {
sip->si_mtx = mtxp;
TAILQ_INIT(&sip->si_tdlist);
}
/*
* Add this thread to the list of selfds listening on this selinfo.
*/
TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
mtx_unlock(sip->si_mtx);
}
/* Wake up a selecting thread. */
void
selwakeup(sip)
struct selinfo *sip;
{
doselwakeup(sip, -1);
}
/* Wake up a selecting thread, and set its priority. */
void
selwakeuppri(sip, pri)
struct selinfo *sip;
int pri;
{
doselwakeup(sip, pri);
}
/*
* Do a wakeup when a selectable event occurs.
*/
static void
doselwakeup(sip, pri)
struct selinfo *sip;
int pri;
{
struct selfd *sfp;
struct selfd *sfn;
struct seltd *stp;
/* If it's not initialized there can't be any waiters. */
if (sip->si_mtx == NULL)
return;
/*
* Locking the selinfo locks all selfds associated with it.
*/
mtx_lock(sip->si_mtx);
TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
/*
* Once we remove this sfp from the list and clear the
* sf_si seltdclear will know to ignore this si.
*/
TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
sfp->sf_si = NULL;
stp = sfp->sf_td;
mtx_lock(&stp->st_mtx);
stp->st_flags |= SELTD_PENDING;
cv_broadcastpri(&stp->st_wait, pri);
mtx_unlock(&stp->st_mtx);
if (refcount_release(&sfp->sf_refs))
uma_zfree(selfd_zone, sfp);
}
mtx_unlock(sip->si_mtx);
}
static void
seltdinit(struct thread *td)
{
struct seltd *stp;
if ((stp = td->td_sel) != NULL)
goto out;
td->td_sel = stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
cv_init(&stp->st_wait, "select");
out:
stp->st_flags = 0;
STAILQ_INIT(&stp->st_selq);
}
static int
seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
{
struct seltd *stp;
int error;
stp = td->td_sel;
/*
* An event of interest may occur while we do not hold the seltd
* locked so check the pending flag before we sleep.
*/
mtx_lock(&stp->st_mtx);
/*
* Any further calls to selrecord will be a rescan.
*/
stp->st_flags |= SELTD_RESCAN;
if (stp->st_flags & SELTD_PENDING) {
mtx_unlock(&stp->st_mtx);
return (0);
}
if (sbt == 0)
error = EWOULDBLOCK;
else if (sbt != -1)
error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
sbt, precision, C_ABSOLUTE);
else
error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
mtx_unlock(&stp->st_mtx);
return (error);
}
void
seltdfini(struct thread *td)
{
struct seltd *stp;
stp = td->td_sel;
if (stp == NULL)
return;
if (stp->st_free1)
uma_zfree(selfd_zone, stp->st_free1);
if (stp->st_free2)
uma_zfree(selfd_zone, stp->st_free2);
td->td_sel = NULL;
free(stp, M_SELECT);
}
/*
* Remove the references to the thread from all of the objects we were
* polling.
*/
static void
seltdclear(struct thread *td)
{
struct seltd *stp;
struct selfd *sfp;
struct selfd *sfn;
stp = td->td_sel;
STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
selfdfree(stp, sfp);
stp->st_flags = 0;
}
static void selectinit(void *);
SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
static void
selectinit(void *dummy __unused)
{
selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, 0);
mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
}
/*
* Set up a syscall return value that follows the convention specified for
* posix_* functions.
*/
int
kern_posix_error(struct thread *td, int error)
{
if (error <= 0)
return (error);
td->td_errno = error;
td->td_pflags |= TDP_NERRNO;
td->td_retval[0] = error;
return (0);
}