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57d025c338
freebsd/sys/kern/sys_generic.c
Davide Italiano 68cefd64ad The variable 'error' in sys_poll() is initialized in declaration to value 
zero but in any case is overwritten by successive copyin(), making the
previous initialization useless. Remove this.
As an added bonus this fixes a style(9) bug.

Discussed with:		kib
Approved by:		gnn (mentor)
MFC after:		3 days
2012-06-17 13:03:50 +00:00

1771 lines
38 KiB
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/*-
* 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/capability.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/file.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>
int iosize_max_clamp = 1;
SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
&iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
/*
* 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 *, int);
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. */
};
static uma_zone_t selfd_zone;
static struct mtx_pool *mtxpool_select;
#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);
}
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));
}
/*
* 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;
int error;
error = fget_read(td, fd, CAP_READ | CAP_SEEK, &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;
int error;
error = fget_read(td, fd, CAP_READ, &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
/* 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);
}
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));
}
/*
* 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;
int error;
error = fget_write(td, fd, CAP_WRITE | CAP_SEEK, &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;
int error;
error = fget_write(td, fd, CAP_WRITE, &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
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)
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;
int error;
AUDIT_ARG_FD(fd);
if (length < 0)
return (EINVAL);
error = fget(td, fd, 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_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
data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
} else
data = (void *)&uap->data;
if (com & IOC_IN) {
error = copyin(uap->data, data, (u_int)size);
if (error) {
if (size > 0)
free(data, M_IOCTLOPS);
return (error);
}
} 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);
if (size > 0)
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;
int error;
int tmp;
AUDIT_ARG_FD(fd);
AUDIT_ARG_CMD(com);
if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0)
return (error);
if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
fdrop(fp, td);
return (EBADF);
}
fdp = td->td_proc->p_fd;
switch (com) {
case FIONCLEX:
FILEDESC_XLOCK(fdp);
fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
FILEDESC_XUNLOCK(fdp);
goto out;
case FIOCLEX:
FILEDESC_XLOCK(fdp);
fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
FILEDESC_XUNLOCK(fdp);
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:
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 atv, rtv, ttv;
int error, lf, ndu, timo;
u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
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);
if (tvp != NULL) {
atv = *tvp;
if (itimerfix(&atv)) {
error = EINVAL;
goto done;
}
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
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;
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=))
break;
ttv = atv;
timevalsub(&ttv, &rtv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
error = seltdwait(td, timo);
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)
{
struct file *fp;
#ifdef CAPABILITIES
struct file *fp_fromcap;
int error;
#endif
if ((fp = fget_unlocked(fdp, fd)) == NULL)
return (EBADF);
#ifdef CAPABILITIES
/*
* If the file descriptor is for a capability, test rights and use
* the file descriptor references by the capability.
*/
error = cap_funwrap(fp, CAP_POLL_EVENT, &fp_fromcap);
if (error) {
fdrop(fp, curthread);
return (error);
}
if (fp != fp_fromcap) {
fhold(fp_fromcap);
fdrop(fp, curthread);
fp = fp_fromcap;
}
#endif /* CAPABILITIES */
*fpp = fp;
return (0);
}
/*
* 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);
}
#ifndef _SYS_SYSPROTO_H_
struct poll_args {
struct pollfd *fds;
u_int nfds;
int timeout;
};
#endif
int
sys_poll(td, uap)
struct thread *td;
struct poll_args *uap;
{
struct pollfd *bits;
struct pollfd smallbits[32];
struct timeval atv, rtv, ttv;
int error, timo;
u_int nfds;
size_t ni;
nfds = uap->nfds;
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(uap->fds, bits, ni);
if (error)
goto done;
if (uap->timeout != INFTIM) {
atv.tv_sec = uap->timeout / 1000;
atv.tv_usec = (uap->timeout % 1000) * 1000;
if (itimerfix(&atv)) {
error = EINVAL;
goto done;
}
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
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;
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=))
break;
ttv = atv;
timevalsub(&ttv, &rtv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
error = seltdwait(td, timo);
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, uap->fds, nfds);
if (error)
goto out;
}
out:
if (ni > sizeof(smallbits))
free(bits, M_TEMP);
return (error);
}
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;
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];
#ifdef CAPABILITIES
if ((fp == NULL)
|| (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 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;
int i;
struct file *fp;
int n = 0;
FILEDESC_SLOCK(fdp);
for (i = 0; i < nfd; i++, fds++) {
if (fds->fd >= fdp->fd_nfiles) {
fds->revents = POLLNVAL;
n++;
} else if (fds->fd < 0) {
fds->revents = 0;
} else {
fp = fdp->fd_ofiles[fds->fd];
#ifdef CAPABILITIES
if ((fp == NULL)
|| (cap_funwrap(fp, CAP_POLL_EVENT, &fp) != 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 atv, rtv, ttv;
int error, timo;
if (tvp != NULL) {
atv = *tvp;
if (itimerfix(&atv))
return (EINVAL);
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
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);
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=)) {
seltdclear(td);
return (EWOULDBLOCK);
}
ttv = atv;
timevalsub(&ttv, &rtv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
error = seltdwait(td, timo);
seltdclear(td);
if (error)
break;
}
/* 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);
mtx_lock(sfp->sf_mtx);
if (sfp->sf_si)
TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
mtx_unlock(sfp->sf_mtx);
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;
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);
}
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, int timo)
{
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 (timo > 0)
error = cv_timedwait_sig(&stp->st_wait, &stp->st_mtx, timo);
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);
}
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