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freebsd-skq/sys/kern/kern_descrip.c
Alfred Perlstein 74aac58b52 Push down Giant in dup(2) and dup2(2), Giant is only needed when 
calling closef() in the case of dup2(2) duping over a descriptor
and when fdalloc must grow or free a filedesc.
2002-01-15 00:58:40 +00:00

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/*
* Copyright (c) 1982, 1986, 1989, 1991, 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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.
*
* @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94
* $FreeBSD$
*/
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/conf.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/unistd.h>
#include <sys/resourcevar.h>
#include <sys/event.h>
#include <sys/sx.h>
#include <sys/socketvar.h>
#include <machine/limits.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table");
MALLOC_DEFINE(M_FILE, "file", "Open file structure");
static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
static d_open_t fdopen;
#define NUMFDESC 64
#define CDEV_MAJOR 22
static struct cdevsw fildesc_cdevsw = {
/* open */ fdopen,
/* close */ noclose,
/* read */ noread,
/* write */ nowrite,
/* ioctl */ noioctl,
/* poll */ nopoll,
/* mmap */ nommap,
/* strategy */ nostrategy,
/* name */ "FD",
/* maj */ CDEV_MAJOR,
/* dump */ nodump,
/* psize */ nopsize,
/* flags */ 0,
};
static int do_dup __P((struct filedesc *fdp, int old, int new, register_t *retval, struct thread *td));
static int badfo_readwrite __P((struct file *fp, struct uio *uio,
struct ucred *cred, int flags, struct thread *td));
static int badfo_ioctl __P((struct file *fp, u_long com, caddr_t data,
struct thread *td));
static int badfo_poll __P((struct file *fp, int events,
struct ucred *cred, struct thread *td));
static int badfo_kqfilter __P((struct file *fp, struct knote *kn));
static int badfo_stat __P((struct file *fp, struct stat *sb, struct thread *td));
static int badfo_close __P((struct file *fp, struct thread *td));
/*
* Descriptor management.
*/
struct filelist filehead; /* head of list of open files */
int nfiles; /* actual number of open files */
extern int cmask;
struct sx filelist_lock; /* sx to protect filelist */
/*
* System calls on descriptors.
*/
#ifndef _SYS_SYSPROTO_H_
struct getdtablesize_args {
int dummy;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
getdtablesize(td, uap)
struct thread *td;
struct getdtablesize_args *uap;
{
struct proc *p = td->td_proc;
mtx_lock(&Giant);
td->td_retval[0] =
min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
mtx_unlock(&Giant);
return (0);
}
/*
* Duplicate a file descriptor to a particular value.
*
* note: keep in mind that a potential race condition exists when closing
* descriptors from a shared descriptor table (via rfork).
*/
#ifndef _SYS_SYSPROTO_H_
struct dup2_args {
u_int from;
u_int to;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
dup2(td, uap)
struct thread *td;
struct dup2_args *uap;
{
struct proc *p = td->td_proc;
register struct filedesc *fdp = td->td_proc->p_fd;
register u_int old = uap->from, new = uap->to;
int i, error;
FILEDESC_LOCK(fdp);
retry:
if (old >= fdp->fd_nfiles ||
fdp->fd_ofiles[old] == NULL ||
new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
new >= maxfilesperproc) {
FILEDESC_UNLOCK(fdp);
return (EBADF);
}
if (old == new) {
td->td_retval[0] = new;
FILEDESC_UNLOCK(fdp);
return (0);
}
if (new >= fdp->fd_nfiles) {
if ((error = fdalloc(td, new, &i))) {
FILEDESC_UNLOCK(fdp);
return (error);
}
if (new != i)
panic("dup2: fdalloc");
/*
* fdalloc() may block, retest everything.
*/
goto retry;
}
error = do_dup(fdp, (int)old, (int)new, td->td_retval, td);
return(error);
}
/*
* Duplicate a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct dup_args {
u_int fd;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
dup(td, uap)
struct thread *td;
struct dup_args *uap;
{
register struct filedesc *fdp;
u_int old;
int new, error;
old = uap->fd;
fdp = td->td_proc->p_fd;
FILEDESC_LOCK(fdp);
if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) {
FILEDESC_UNLOCK(fdp);
return (EBADF);
}
if ((error = fdalloc(td, 0, &new))) {
FILEDESC_UNLOCK(fdp);
return (error);
}
error = do_dup(fdp, (int)old, new, td->td_retval, td);
return (error);
}
/*
* The file control system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct fcntl_args {
int fd;
int cmd;
long arg;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
fcntl(td, uap)
struct thread *td;
register struct fcntl_args *uap;
{
register struct proc *p = td->td_proc;
register struct filedesc *fdp;
register struct file *fp;
register char *pop;
struct vnode *vp;
int i, tmp, error = 0, flg = F_POSIX;
struct flock fl;
u_int newmin;
struct proc *leaderp;
mtx_lock(&Giant);
fdp = p->p_fd;
FILEDESC_LOCK(fdp);
if ((unsigned)uap->fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL) {
FILEDESC_UNLOCK(fdp);
error = EBADF;
goto done2;
}
pop = &fdp->fd_ofileflags[uap->fd];
switch (uap->cmd) {
case F_DUPFD:
newmin = uap->arg;
if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
newmin >= maxfilesperproc) {
FILEDESC_UNLOCK(fdp);
error = EINVAL;
break;
}
if ((error = fdalloc(td, newmin, &i))) {
FILEDESC_UNLOCK(fdp);
break;
}
error = do_dup(fdp, uap->fd, i, td->td_retval, td);
break;
case F_GETFD:
td->td_retval[0] = *pop & 1;
FILEDESC_UNLOCK(fdp);
break;
case F_SETFD:
*pop = (*pop &~ 1) | (uap->arg & 1);
FILEDESC_UNLOCK(fdp);
break;
case F_GETFL:
FILE_LOCK(fp);
FILEDESC_UNLOCK(fdp);
td->td_retval[0] = OFLAGS(fp->f_flag);
FILE_UNLOCK(fp);
break;
case F_SETFL:
fhold(fp);
FILEDESC_UNLOCK(fdp);
fp->f_flag &= ~FCNTLFLAGS;
fp->f_flag |= FFLAGS(uap->arg & ~O_ACCMODE) & FCNTLFLAGS;
tmp = fp->f_flag & FNONBLOCK;
error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td);
if (error) {
fdrop(fp, td);
break;
}
tmp = fp->f_flag & FASYNC;
error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, td);
if (!error) {
fdrop(fp, td);
break;
}
fp->f_flag &= ~FNONBLOCK;
tmp = 0;
(void)fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td);
fdrop(fp, td);
break;
case F_GETOWN:
fhold(fp);
FILEDESC_UNLOCK(fdp);
error = fo_ioctl(fp, FIOGETOWN, (caddr_t)td->td_retval, td);
fdrop(fp, td);
break;
case F_SETOWN:
fhold(fp);
FILEDESC_UNLOCK(fdp);
error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&uap->arg, td);
fdrop(fp, td);
break;
case F_SETLKW:
flg |= F_WAIT;
/* Fall into F_SETLK */
case F_SETLK:
if (fp->f_type != DTYPE_VNODE) {
FILEDESC_UNLOCK(fdp);
error = EBADF;
break;
}
vp = (struct vnode *)fp->f_data;
/*
* copyin/lockop may block
*/
fhold(fp);
FILEDESC_UNLOCK(fdp);
vp = (struct vnode *)fp->f_data;
/* Copy in the lock structure */
error = copyin((caddr_t)(intptr_t)uap->arg, (caddr_t)&fl,
sizeof(fl));
if (error) {
fdrop(fp, td);
break;
}
if (fl.l_whence == SEEK_CUR) {
if (fp->f_offset < 0 ||
(fl.l_start > 0 &&
fp->f_offset > OFF_MAX - fl.l_start)) {
fdrop(fp, td);
error = EOVERFLOW;
break;
}
fl.l_start += fp->f_offset;
}
switch (fl.l_type) {
case F_RDLCK:
if ((fp->f_flag & FREAD) == 0) {
error = EBADF;
break;
}
PROC_LOCK(p);
p->p_flag |= P_ADVLOCK;
leaderp = p->p_leader;
PROC_UNLOCK(p);
error = VOP_ADVLOCK(vp, (caddr_t)leaderp, F_SETLK,
&fl, flg);
break;
case F_WRLCK:
if ((fp->f_flag & FWRITE) == 0) {
error = EBADF;
break;
}
PROC_LOCK(p);
p->p_flag |= P_ADVLOCK;
leaderp = p->p_leader;
PROC_UNLOCK(p);
error = VOP_ADVLOCK(vp, (caddr_t)leaderp, F_SETLK,
&fl, flg);
break;
case F_UNLCK:
PROC_LOCK(p);
leaderp = p->p_leader;
PROC_UNLOCK(p);
error = VOP_ADVLOCK(vp, (caddr_t)leaderp, F_UNLCK,
&fl, F_POSIX);
break;
default:
error = EINVAL;
break;
}
fdrop(fp, td);
break;
case F_GETLK:
if (fp->f_type != DTYPE_VNODE) {
FILEDESC_UNLOCK(fdp);
error = EBADF;
break;
}
vp = (struct vnode *)fp->f_data;
/*
* copyin/lockop may block
*/
fhold(fp);
FILEDESC_UNLOCK(fdp);
vp = (struct vnode *)fp->f_data;
/* Copy in the lock structure */
error = copyin((caddr_t)(intptr_t)uap->arg, (caddr_t)&fl,
sizeof(fl));
if (error) {
fdrop(fp, td);
break;
}
if (fl.l_type != F_RDLCK && fl.l_type != F_WRLCK &&
fl.l_type != F_UNLCK) {
fdrop(fp, td);
error = EINVAL;
break;
}
if (fl.l_whence == SEEK_CUR) {
if ((fl.l_start > 0 &&
fp->f_offset > OFF_MAX - fl.l_start) ||
(fl.l_start < 0 &&
fp->f_offset < OFF_MIN - fl.l_start)) {
fdrop(fp, td);
error = EOVERFLOW;
break;
}
fl.l_start += fp->f_offset;
}
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK,
&fl, F_POSIX);
fdrop(fp, td);
if (error == 0) {
error = copyout((caddr_t)&fl,
(caddr_t)(intptr_t)uap->arg, sizeof(fl));
}
break;
default:
FILEDESC_UNLOCK(fdp);
error = EINVAL;
break;
}
done2:
mtx_unlock(&Giant);
return (error);
}
/*
* Common code for dup, dup2, and fcntl(F_DUPFD).
* filedesc must be locked, but will be unlocked as a side effect.
*/
static int
do_dup(fdp, old, new, retval, td)
register struct filedesc *fdp;
register int old, new;
register_t *retval;
struct thread *td;
{
struct file *fp;
struct file *delfp;
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
/*
* Save info on the descriptor being overwritten. We have
* to do the unmap now, but we cannot close it without
* introducing an ownership race for the slot.
*/
delfp = fdp->fd_ofiles[new];
#if 0
if (delfp && (fdp->fd_ofileflags[new] & UF_MAPPED))
(void) munmapfd(td, new);
#endif
/*
* Duplicate the source descriptor, update lastfile
*/
fp = fdp->fd_ofiles[old];
fdp->fd_ofiles[new] = fp;
fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
fhold(fp);
if (new > fdp->fd_lastfile)
fdp->fd_lastfile = new;
*retval = new;
FILEDESC_UNLOCK(fdp);
/*
* If we dup'd over a valid file, we now own the reference to it
* and must dispose of it using closef() semantics (as if a
* close() were performed on it).
*/
if (delfp) {
mtx_lock(&Giant);
(void) closef(delfp, td);
mtx_unlock(&Giant);
}
return (0);
}
/*
* If sigio is on the list associated with a process or process group,
* disable signalling from the device, remove sigio from the list and
* free sigio.
*/
void
funsetown(sigio)
struct sigio *sigio;
{
int s;
if (sigio == NULL)
return;
s = splhigh();
*(sigio->sio_myref) = NULL;
splx(s);
if (sigio->sio_pgid < 0) {
SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
sigio, sio_pgsigio);
} else /* if ((*sigiop)->sio_pgid > 0) */ {
SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
sigio, sio_pgsigio);
}
crfree(sigio->sio_ucred);
FREE(sigio, M_SIGIO);
}
/* Free a list of sigio structures. */
void
funsetownlst(sigiolst)
struct sigiolst *sigiolst;
{
struct sigio *sigio;
while ((sigio = SLIST_FIRST(sigiolst)) != NULL)
funsetown(sigio);
}
/*
* This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
*
* After permission checking, add a sigio structure to the sigio list for
* the process or process group.
*/
int
fsetown(pgid, sigiop)
pid_t pgid;
struct sigio **sigiop;
{
struct proc *proc;
struct pgrp *pgrp;
struct sigio *sigio;
int s;
if (pgid == 0) {
funsetown(*sigiop);
return (0);
}
if (pgid > 0) {
proc = pfind(pgid);
if (proc == NULL)
return (ESRCH);
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (proc->p_session != curthread->td_proc->p_session) {
PROC_UNLOCK(proc);
return (EPERM);
}
PROC_UNLOCK(proc);
pgrp = NULL;
} else /* if (pgid < 0) */ {
pgrp = pgfind(-pgid);
if (pgrp == NULL)
return (ESRCH);
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (pgrp->pg_session != curthread->td_proc->p_session)
return (EPERM);
proc = NULL;
}
funsetown(*sigiop);
MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK);
if (pgid > 0) {
SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
sigio->sio_proc = proc;
} else {
SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
sigio->sio_pgrp = pgrp;
}
sigio->sio_pgid = pgid;
sigio->sio_ucred = crhold(curthread->td_proc->p_ucred);
sigio->sio_myref = sigiop;
s = splhigh();
*sigiop = sigio;
splx(s);
return (0);
}
/*
* This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
*/
pid_t
fgetown(sigio)
struct sigio *sigio;
{
return (sigio != NULL ? sigio->sio_pgid : 0);
}
/*
* Close a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct close_args {
int fd;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
close(td, uap)
struct thread *td;
struct close_args *uap;
{
register struct filedesc *fdp;
register struct file *fp;
register int fd = uap->fd;
int error = 0;
mtx_lock(&Giant);
fdp = td->td_proc->p_fd;
FILEDESC_LOCK(fdp);
if ((unsigned)fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[fd]) == NULL) {
FILEDESC_UNLOCK(fdp);
error = EBADF;
goto done2;
}
#if 0
if (fdp->fd_ofileflags[fd] & UF_MAPPED)
(void) munmapfd(td, fd);
#endif
fdp->fd_ofiles[fd] = NULL;
fdp->fd_ofileflags[fd] = 0;
/*
* we now hold the fp reference that used to be owned by the descriptor
* array.
*/
while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
fdp->fd_lastfile--;
if (fd < fdp->fd_freefile)
fdp->fd_freefile = fd;
if (fd < fdp->fd_knlistsize) {
FILEDESC_UNLOCK(fdp);
knote_fdclose(td, fd);
} else
FILEDESC_UNLOCK(fdp);
error = closef(fp, td);
done2:
mtx_unlock(&Giant);
return(error);
}
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct ofstat_args {
int fd;
struct ostat *sb;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
ofstat(td, uap)
struct thread *td;
register struct ofstat_args *uap;
{
struct file *fp;
struct stat ub;
struct ostat oub;
int error;
mtx_lock(&Giant);
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
error = fo_stat(fp, &ub, td);
if (error == 0) {
cvtstat(&ub, &oub);
error = copyout((caddr_t)&oub, (caddr_t)uap->sb, sizeof (oub));
}
fdrop(fp, td);
done2:
mtx_unlock(&Giant);
return (error);
}
#endif /* COMPAT_43 || COMPAT_SUNOS */
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct fstat_args {
int fd;
struct stat *sb;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
fstat(td, uap)
struct thread *td;
struct fstat_args *uap;
{
struct file *fp;
struct stat ub;
int error;
mtx_lock(&Giant);
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
error = fo_stat(fp, &ub, td);
if (error == 0)
error = copyout((caddr_t)&ub, (caddr_t)uap->sb, sizeof (ub));
fdrop(fp, td);
done2:
mtx_unlock(&Giant);
return (error);
}
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct nfstat_args {
int fd;
struct nstat *sb;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
nfstat(td, uap)
struct thread *td;
register struct nfstat_args *uap;
{
struct file *fp;
struct stat ub;
struct nstat nub;
int error;
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
error = fo_stat(fp, &ub, td);
if (error == 0) {
cvtnstat(&ub, &nub);
error = copyout((caddr_t)&nub, (caddr_t)uap->sb, sizeof (nub));
}
fdrop(fp, td);
done2:
mtx_unlock(&Giant);
return (error);
}
/*
* Return pathconf information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct fpathconf_args {
int fd;
int name;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
fpathconf(td, uap)
struct thread *td;
register struct fpathconf_args *uap;
{
struct file *fp;
struct vnode *vp;
int error;
if ((error = fget(td, uap->fd, &fp)) != 0)
return (error);
switch (fp->f_type) {
case DTYPE_PIPE:
case DTYPE_SOCKET:
if (uap->name != _PC_PIPE_BUF) {
error = EINVAL;
} else {
td->td_retval[0] = PIPE_BUF;
error = 0;
}
break;
case DTYPE_FIFO:
case DTYPE_VNODE:
vp = (struct vnode *)fp->f_data;
mtx_lock(&Giant);
error = VOP_PATHCONF(vp, uap->name, td->td_retval);
mtx_unlock(&Giant);
break;
default:
error = EOPNOTSUPP;
break;
}
fdrop(fp, td);
return(error);
}
/*
* Allocate a file descriptor for the process.
*/
static int fdexpand;
SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, "");
int
fdalloc(td, want, result)
struct thread *td;
int want;
int *result;
{
struct proc *p = td->td_proc;
register struct filedesc *fdp = td->td_proc->p_fd;
register int i;
int lim, last, nfiles;
struct file **newofile, **oldofile;
char *newofileflags;
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
/*
* Search for a free descriptor starting at the higher
* of want or fd_freefile. If that fails, consider
* expanding the ofile array.
*/
lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
for (;;) {
last = min(fdp->fd_nfiles, lim);
if ((i = want) < fdp->fd_freefile)
i = fdp->fd_freefile;
for (; i < last; i++) {
if (fdp->fd_ofiles[i] == NULL) {
fdp->fd_ofileflags[i] = 0;
if (i > fdp->fd_lastfile)
fdp->fd_lastfile = i;
if (want <= fdp->fd_freefile)
fdp->fd_freefile = i;
*result = i;
return (0);
}
}
/*
* No space in current array. Expand?
*/
if (fdp->fd_nfiles >= lim)
return (EMFILE);
if (fdp->fd_nfiles < NDEXTENT)
nfiles = NDEXTENT;
else
nfiles = 2 * fdp->fd_nfiles;
FILEDESC_UNLOCK(fdp);
mtx_lock(&Giant);
MALLOC(newofile, struct file **, nfiles * OFILESIZE,
M_FILEDESC, M_WAITOK);
mtx_unlock(&Giant);
FILEDESC_LOCK(fdp);
/*
* deal with file-table extend race that might have occured
* when malloc was blocked.
*/
if (fdp->fd_nfiles >= nfiles) {
FILEDESC_UNLOCK(fdp);
mtx_lock(&Giant);
FREE(newofile, M_FILEDESC);
mtx_unlock(&Giant);
FILEDESC_LOCK(fdp);
continue;
}
newofileflags = (char *) &newofile[nfiles];
/*
* Copy the existing ofile and ofileflags arrays
* and zero the new portion of each array.
*/
bcopy(fdp->fd_ofiles, newofile,
(i = sizeof(struct file *) * fdp->fd_nfiles));
bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i);
bcopy(fdp->fd_ofileflags, newofileflags,
(i = sizeof(char) * fdp->fd_nfiles));
bzero(newofileflags + i, nfiles * sizeof(char) - i);
if (fdp->fd_nfiles > NDFILE)
oldofile = fdp->fd_ofiles;
else
oldofile = NULL;
fdp->fd_ofiles = newofile;
fdp->fd_ofileflags = newofileflags;
fdp->fd_nfiles = nfiles;
fdexpand++;
if (oldofile != NULL) {
mtx_lock(&Giant);
FREE(oldofile, M_FILEDESC);
mtx_unlock(&Giant);
}
}
return (0);
}
/*
* Check to see whether n user file descriptors
* are available to the process p.
*/
int
fdavail(td, n)
struct thread *td;
register int n;
{
struct proc *p = td->td_proc;
register struct filedesc *fdp = td->td_proc->p_fd;
register struct file **fpp;
register int i, lim, last;
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
return (1);
last = min(fdp->fd_nfiles, lim);
fpp = &fdp->fd_ofiles[fdp->fd_freefile];
for (i = last - fdp->fd_freefile; --i >= 0; fpp++) {
if (*fpp == NULL && --n <= 0)
return (1);
}
return (0);
}
/*
* Create a new open file structure and allocate
* a file decriptor for the process that refers to it.
*/
int
falloc(td, resultfp, resultfd)
register struct thread *td;
struct file **resultfp;
int *resultfd;
{
struct proc *p = td->td_proc;
register struct file *fp, *fq;
int error, i;
sx_xlock(&filelist_lock);
if (nfiles >= maxfiles) {
sx_xunlock(&filelist_lock);
tablefull("file");
return (ENFILE);
}
nfiles++;
sx_xunlock(&filelist_lock);
/*
* Allocate a new file descriptor.
* If the process has file descriptor zero open, add to the list
* of open files at that point, otherwise put it at the front of
* the list of open files.
*/
MALLOC(fp, struct file *, sizeof(struct file), M_FILE, M_WAITOK | M_ZERO);
/*
* wait until after malloc (which may have blocked) returns before
* allocating the slot, else a race might have shrunk it if we had
* allocated it before the malloc.
*/
FILEDESC_LOCK(p->p_fd);
if ((error = fdalloc(td, 0, &i))) {
FILEDESC_UNLOCK(p->p_fd);
sx_xlock(&filelist_lock);
nfiles--;
sx_xunlock(&filelist_lock);
FREE(fp, M_FILE);
return (error);
}
mtx_init(&fp->f_mtx, "file structure", MTX_DEF);
fp->f_gcflag = 0;
fp->f_count = 1;
fp->f_cred = crhold(p->p_ucred);
fp->f_ops = &badfileops;
fp->f_seqcount = 1;
FILEDESC_UNLOCK(p->p_fd);
sx_xlock(&filelist_lock);
FILEDESC_LOCK(p->p_fd);
if ((fq = p->p_fd->fd_ofiles[0])) {
LIST_INSERT_AFTER(fq, fp, f_list);
} else {
LIST_INSERT_HEAD(&filehead, fp, f_list);
}
p->p_fd->fd_ofiles[i] = fp;
FILEDESC_UNLOCK(p->p_fd);
sx_xunlock(&filelist_lock);
if (resultfp)
*resultfp = fp;
if (resultfd)
*resultfd = i;
return (0);
}
/*
* Free a file descriptor.
*/
void
ffree(fp)
register struct file *fp;
{
KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!"));
sx_xlock(&filelist_lock);
LIST_REMOVE(fp, f_list);
nfiles--;
sx_xunlock(&filelist_lock);
crfree(fp->f_cred);
mtx_destroy(&fp->f_mtx);
FREE(fp, M_FILE);
}
/*
* Build a new filedesc structure.
*/
struct filedesc *
fdinit(td)
struct thread *td;
{
register struct filedesc0 *newfdp;
register struct filedesc *fdp = td->td_proc->p_fd;
MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0),
M_FILEDESC, M_WAITOK | M_ZERO);
mtx_init(&newfdp->fd_fd.fd_mtx, "filedesc structure", MTX_DEF);
FILEDESC_LOCK(&newfdp->fd_fd);
newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
if (newfdp->fd_fd.fd_cdir)
VREF(newfdp->fd_fd.fd_cdir);
newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
if (newfdp->fd_fd.fd_rdir)
VREF(newfdp->fd_fd.fd_rdir);
newfdp->fd_fd.fd_jdir = fdp->fd_jdir;
if (newfdp->fd_fd.fd_jdir)
VREF(newfdp->fd_fd.fd_jdir);
/* Create the file descriptor table. */
newfdp->fd_fd.fd_refcnt = 1;
newfdp->fd_fd.fd_cmask = cmask;
newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
newfdp->fd_fd.fd_nfiles = NDFILE;
newfdp->fd_fd.fd_knlistsize = -1;
FILEDESC_UNLOCK(&newfdp->fd_fd);
return (&newfdp->fd_fd);
}
/*
* Share a filedesc structure.
*/
struct filedesc *
fdshare(p)
struct proc *p;
{
FILEDESC_LOCK(p->p_fd);
p->p_fd->fd_refcnt++;
FILEDESC_UNLOCK(p->p_fd);
return (p->p_fd);
}
/*
* Copy a filedesc structure.
*/
struct filedesc *
fdcopy(td)
struct thread *td;
{
register struct filedesc *newfdp, *fdp = td->td_proc->p_fd;
register struct file **fpp;
register int i, j;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return (NULL);
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
FILEDESC_UNLOCK(fdp);
MALLOC(newfdp, struct filedesc *, sizeof(struct filedesc0),
M_FILEDESC, M_WAITOK);
FILEDESC_LOCK(fdp);
bcopy(fdp, newfdp, sizeof(struct filedesc));
FILEDESC_UNLOCK(fdp);
bzero(&newfdp->fd_mtx, sizeof(newfdp->fd_mtx));
mtx_init(&newfdp->fd_mtx, "filedesc structure", MTX_DEF);
if (newfdp->fd_cdir)
VREF(newfdp->fd_cdir);
if (newfdp->fd_rdir)
VREF(newfdp->fd_rdir);
if (newfdp->fd_jdir)
VREF(newfdp->fd_jdir);
newfdp->fd_refcnt = 1;
/*
* If the number of open files fits in the internal arrays
* of the open file structure, use them, otherwise allocate
* additional memory for the number of descriptors currently
* in use.
*/
FILEDESC_LOCK(fdp);
newfdp->fd_lastfile = fdp->fd_lastfile;
newfdp->fd_nfiles = fdp->fd_nfiles;
if (newfdp->fd_lastfile < NDFILE) {
newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles;
newfdp->fd_ofileflags =
((struct filedesc0 *) newfdp)->fd_dfileflags;
i = NDFILE;
} else {
/*
* Compute the smallest multiple of NDEXTENT needed
* for the file descriptors currently in use,
* allowing the table to shrink.
*/
retry:
i = newfdp->fd_nfiles;
while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
i /= 2;
FILEDESC_UNLOCK(fdp);
MALLOC(newfdp->fd_ofiles, struct file **, i * OFILESIZE,
M_FILEDESC, M_WAITOK);
FILEDESC_LOCK(fdp);
newfdp->fd_lastfile = fdp->fd_lastfile;
newfdp->fd_nfiles = fdp->fd_nfiles;
j = newfdp->fd_nfiles;
while (j > 2 * NDEXTENT && j > newfdp->fd_lastfile * 2)
j /= 2;
if (i != j) {
/*
* The size of the original table has changed.
* Go over once again.
*/
FILEDESC_UNLOCK(fdp);
FREE(newfdp->fd_ofiles, M_FILEDESC);
FILEDESC_LOCK(fdp);
newfdp->fd_lastfile = fdp->fd_lastfile;
newfdp->fd_nfiles = fdp->fd_nfiles;
goto retry;
}
newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
}
newfdp->fd_nfiles = i;
bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **));
bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char));
/*
* kq descriptors cannot be copied.
*/
if (newfdp->fd_knlistsize != -1) {
fpp = &newfdp->fd_ofiles[newfdp->fd_lastfile];
for (i = newfdp->fd_lastfile; i >= 0; i--, fpp--) {
if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE) {
*fpp = NULL;
if (i < newfdp->fd_freefile)
newfdp->fd_freefile = i;
}
if (*fpp == NULL && i == newfdp->fd_lastfile && i > 0)
newfdp->fd_lastfile--;
}
newfdp->fd_knlist = NULL;
newfdp->fd_knlistsize = -1;
newfdp->fd_knhash = NULL;
newfdp->fd_knhashmask = 0;
}
fpp = newfdp->fd_ofiles;
for (i = newfdp->fd_lastfile; i-- >= 0; fpp++) {
if (*fpp != NULL) {
fhold(*fpp);
}
}
return (newfdp);
}
/*
* Release a filedesc structure.
*/
void
fdfree(td)
struct thread *td;
{
register struct filedesc *fdp = td->td_proc->p_fd;
struct file **fpp;
register int i;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return;
FILEDESC_LOCK(fdp);
if (--fdp->fd_refcnt > 0) {
FILEDESC_UNLOCK(fdp);
return;
}
/*
* we are the last reference to the structure, we can
* safely assume it will not change out from under us.
*/
FILEDESC_UNLOCK(fdp);
fpp = fdp->fd_ofiles;
for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
if (*fpp)
(void) closef(*fpp, td);
}
if (fdp->fd_nfiles > NDFILE)
FREE(fdp->fd_ofiles, M_FILEDESC);
if (fdp->fd_cdir)
vrele(fdp->fd_cdir);
if (fdp->fd_rdir)
vrele(fdp->fd_rdir);
if (fdp->fd_jdir)
vrele(fdp->fd_jdir);
if (fdp->fd_knlist)
FREE(fdp->fd_knlist, M_KQUEUE);
if (fdp->fd_knhash)
FREE(fdp->fd_knhash, M_KQUEUE);
mtx_destroy(&fdp->fd_mtx);
FREE(fdp, M_FILEDESC);
}
/*
* For setugid programs, we don't want to people to use that setugidness
* to generate error messages which write to a file which otherwise would
* otherwise be off-limits to the process.
*
* This is a gross hack to plug the hole. A better solution would involve
* a special vop or other form of generalized access control mechanism. We
* go ahead and just reject all procfs file systems accesses as dangerous.
*
* Since setugidsafety calls this only for fd 0, 1 and 2, this check is
* sufficient. We also don't for check setugidness since we know we are.
*/
static int
is_unsafe(struct file *fp)
{
if (fp->f_type == DTYPE_VNODE &&
((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS)
return (1);
return (0);
}
/*
* Make this setguid thing safe, if at all possible.
*/
void
setugidsafety(td)
struct thread *td;
{
struct filedesc *fdp = td->td_proc->p_fd;
register int i;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return;
/*
* note: fdp->fd_ofiles may be reallocated out from under us while
* we are blocked in a close. Be careful!
*/
FILEDESC_LOCK(fdp);
for (i = 0; i <= fdp->fd_lastfile; i++) {
if (i > 2)
break;
if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) {
struct file *fp;
#if 0
if ((fdp->fd_ofileflags[i] & UF_MAPPED) != 0)
(void) munmapfd(td, i);
#endif
if (i < fdp->fd_knlistsize) {
FILEDESC_UNLOCK(fdp);
knote_fdclose(td, i);
FILEDESC_LOCK(fdp);
}
/*
* NULL-out descriptor prior to close to avoid
* a race while close blocks.
*/
fp = fdp->fd_ofiles[i];
fdp->fd_ofiles[i] = NULL;
fdp->fd_ofileflags[i] = 0;
if (i < fdp->fd_freefile)
fdp->fd_freefile = i;
FILEDESC_UNLOCK(fdp);
(void) closef(fp, td);
FILEDESC_LOCK(fdp);
}
}
while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
fdp->fd_lastfile--;
FILEDESC_UNLOCK(fdp);
}
/*
* Close any files on exec?
*/
void
fdcloseexec(td)
struct thread *td;
{
struct filedesc *fdp = td->td_proc->p_fd;
register int i;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return;
FILEDESC_LOCK(fdp);
/*
* We cannot cache fd_ofiles or fd_ofileflags since operations
* may block and rip them out from under us.
*/
for (i = 0; i <= fdp->fd_lastfile; i++) {
if (fdp->fd_ofiles[i] != NULL &&
(fdp->fd_ofileflags[i] & UF_EXCLOSE)) {
struct file *fp;
#if 0
if (fdp->fd_ofileflags[i] & UF_MAPPED)
(void) munmapfd(td, i);
#endif
if (i < fdp->fd_knlistsize) {
FILEDESC_UNLOCK(fdp);
knote_fdclose(td, i);
FILEDESC_LOCK(fdp);
}
/*
* NULL-out descriptor prior to close to avoid
* a race while close blocks.
*/
fp = fdp->fd_ofiles[i];
fdp->fd_ofiles[i] = NULL;
fdp->fd_ofileflags[i] = 0;
if (i < fdp->fd_freefile)
fdp->fd_freefile = i;
FILEDESC_UNLOCK(fdp);
(void) closef(fp, td);
FILEDESC_LOCK(fdp);
}
}
while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
fdp->fd_lastfile--;
FILEDESC_UNLOCK(fdp);
}
/*
* Internal form of close.
* Decrement reference count on file structure.
* Note: td may be NULL when closing a file
* that was being passed in a message.
*/
int
closef(fp, td)
register struct file *fp;
register struct thread *td;
{
struct vnode *vp;
struct flock lf;
if (fp == NULL)
return (0);
/*
* POSIX record locking dictates that any close releases ALL
* locks owned by this process. This is handled by setting
* a flag in the unlock to free ONLY locks obeying POSIX
* semantics, and not to free BSD-style file locks.
* If the descriptor was in a message, POSIX-style locks
* aren't passed with the descriptor.
*/
if (td && (td->td_proc->p_flag & P_ADVLOCK) &&
fp->f_type == DTYPE_VNODE) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = (struct vnode *)fp->f_data;
(void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader,
F_UNLCK, &lf, F_POSIX);
}
return (fdrop(fp, td));
}
/*
* Drop reference on struct file passed in, may call closef if the
* reference hits zero.
*/
int
fdrop(fp, td)
struct file *fp;
struct thread *td;
{
FILE_LOCK(fp);
return (fdrop_locked(fp, td));
}
/*
* Extract the file pointer associated with the specified descriptor for
* the current user process.
*
* If the descriptor doesn't exist, EBADF is returned.
*
* If the descriptor exists but doesn't match 'flags' then
* return EBADF for read attempts and EINVAL for write attempts.
*
* If 'hold' is set (non-zero) the file's refcount will be bumped on return.
* It should be droped with fdrop().
* If it is not set, then the refcount will not be bumped however the
* thread's filedesc struct will be returned locked (for fgetsock).
*
* If an error occured the non-zero error is returned and *fpp is set to NULL.
* Otherwise *fpp is set and zero is returned.
*/
static __inline
int
_fget(struct thread *td, int fd, struct file **fpp, int flags, int hold)
{
struct filedesc *fdp;
struct file *fp;
*fpp = NULL;
if (td == NULL || (fdp = td->td_proc->p_fd) == NULL)
return(EBADF);
FILEDESC_LOCK(fdp);
if (fd < 0 || (u_int)fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[fd]) == NULL ||
fp->f_ops == &badfileops) {
FILEDESC_UNLOCK(fdp);
return(EBADF);
}
/*
* Note: FREAD failures returns EBADF to maintain backwards
* compatibility with what routines returned before.
*
* Only one flag, or 0, may be specified.
*/
if (flags == FREAD && (fp->f_flag & FREAD) == 0) {
FILEDESC_UNLOCK(fdp);
return(EBADF);
}
if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) {
FILEDESC_UNLOCK(fdp);
return(EINVAL);
}
if (hold) {
fhold(fp);
FILEDESC_UNLOCK(fdp);
}
*fpp = fp;
return(0);
}
int
fget(struct thread *td, int fd, struct file **fpp)
{
return(_fget(td, fd, fpp, 0, 1));
}
int
fget_read(struct thread *td, int fd, struct file **fpp)
{
return(_fget(td, fd, fpp, FREAD, 1));
}
int
fget_write(struct thread *td, int fd, struct file **fpp)
{
return(_fget(td, fd, fpp, FWRITE, 1));
}
/*
* Like fget() but loads the underlying vnode, or returns an error if
* the descriptor does not represent a vnode. Note that pipes use vnodes
* but never have VM objects (so VOP_GETVOBJECT() calls will return an
* error). The returned vnode will be vref()d.
*/
static __inline
int
_fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags)
{
struct file *fp;
int error;
*vpp = NULL;
if ((error = _fget(td, fd, &fp, 0, 0)) != 0)
return (error);
if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) {
error = EINVAL;
} else {
*vpp = (struct vnode *)fp->f_data;
vref(*vpp);
}
FILEDESC_UNLOCK(td->td_proc->p_fd);
return (error);
}
int
fgetvp(struct thread *td, int fd, struct vnode **vpp)
{
return(_fgetvp(td, fd, vpp, 0));
}
int
fgetvp_read(struct thread *td, int fd, struct vnode **vpp)
{
return(_fgetvp(td, fd, vpp, FREAD));
}
int
fgetvp_write(struct thread *td, int fd, struct vnode **vpp)
{
return(_fgetvp(td, fd, vpp, FWRITE));
}
/*
* Like fget() but loads the underlying socket, or returns an error if
* the descriptor does not represent a socket.
*
* We bump the ref count on the returned socket. XXX Also obtain the SX lock in
* the future.
*/
int
fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp)
{
struct file *fp;
int error;
*spp = NULL;
if (fflagp)
*fflagp = 0;
if ((error = _fget(td, fd, &fp, 0, 0)) != 0)
return (error);
if (fp->f_type != DTYPE_SOCKET) {
error = ENOTSOCK;
} else {
*spp = (struct socket *)fp->f_data;
if (fflagp)
*fflagp = fp->f_flag;
soref(*spp);
}
FILEDESC_UNLOCK(td->td_proc->p_fd);
return(error);
}
/*
* Drop the reference count on the the socket and XXX release the SX lock in
* the future. The last reference closes the socket.
*/
void
fputsock(struct socket *so)
{
sorele(so);
}
/*
* Drop reference on struct file passed in, may call closef if the
* reference hits zero.
* Expects struct file locked, and will unlock it.
*/
int
fdrop_locked(fp, td)
struct file *fp;
struct thread *td;
{
struct flock lf;
struct vnode *vp;
int error;
FILE_LOCK_ASSERT(fp, MA_OWNED);
if (--fp->f_count > 0) {
FILE_UNLOCK(fp);
return (0);
}
if (fp->f_count < 0)
panic("fdrop: count < 0");
if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = (struct vnode *)fp->f_data;
FILE_UNLOCK(fp);
(void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
} else
FILE_UNLOCK(fp);
if (fp->f_ops != &badfileops)
error = fo_close(fp, td);
else
error = 0;
ffree(fp);
return (error);
}
/*
* Apply an advisory lock on a file descriptor.
*
* Just attempt to get a record lock of the requested type on
* the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
*/
#ifndef _SYS_SYSPROTO_H_
struct flock_args {
int fd;
int how;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
flock(td, uap)
struct thread *td;
register struct flock_args *uap;
{
struct file *fp;
struct vnode *vp;
struct flock lf;
int error;
if ((error = fget(td, uap->fd, &fp)) != 0)
return (error);
if (fp->f_type != DTYPE_VNODE) {
fdrop(fp, td);
return (EOPNOTSUPP);
}
mtx_lock(&Giant);
vp = (struct vnode *)fp->f_data;
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
if (uap->how & LOCK_UN) {
lf.l_type = F_UNLCK;
FILE_LOCK(fp);
fp->f_flag &= ~FHASLOCK;
FILE_UNLOCK(fp);
error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
goto done2;
}
if (uap->how & LOCK_EX)
lf.l_type = F_WRLCK;
else if (uap->how & LOCK_SH)
lf.l_type = F_RDLCK;
else {
error = EBADF;
goto done2;
}
FILE_LOCK(fp);
fp->f_flag |= FHASLOCK;
FILE_UNLOCK(fp);
error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf,
(uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT);
done2:
fdrop(fp, td);
mtx_unlock(&Giant);
return (error);
}
/*
* File Descriptor pseudo-device driver (/dev/fd/).
*
* Opening minor device N dup()s the file (if any) connected to file
* descriptor N belonging to the calling process. Note that this driver
* consists of only the ``open()'' routine, because all subsequent
* references to this file will be direct to the other driver.
*/
/* ARGSUSED */
static int
fdopen(dev, mode, type, td)
dev_t dev;
int mode, type;
struct thread *td;
{
/*
* XXX Kludge: set curthread->td_dupfd to contain the value of the
* the file descriptor being sought for duplication. The error
* return ensures that the vnode for this device will be released
* by vn_open. Open will detect this special error and take the
* actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
* will simply report the error.
*/
td->td_dupfd = dev2unit(dev);
return (ENODEV);
}
/*
* Duplicate the specified descriptor to a free descriptor.
*/
int
dupfdopen(td, fdp, indx, dfd, mode, error)
struct thread *td;
struct filedesc *fdp;
int indx, dfd;
int mode;
int error;
{
register struct file *wfp;
struct file *fp;
/*
* If the to-be-dup'd fd number is greater than the allowed number
* of file descriptors, or the fd to be dup'd has already been
* closed, then reject.
*/
FILEDESC_LOCK(fdp);
if ((u_int)dfd >= fdp->fd_nfiles ||
(wfp = fdp->fd_ofiles[dfd]) == NULL) {
FILEDESC_UNLOCK(fdp);
return (EBADF);
}
/*
* There are two cases of interest here.
*
* For ENODEV simply dup (dfd) to file descriptor
* (indx) and return.
*
* For ENXIO steal away the file structure from (dfd) and
* store it in (indx). (dfd) is effectively closed by
* this operation.
*
* Any other error code is just returned.
*/
switch (error) {
case ENODEV:
/*
* Check that the mode the file is being opened for is a
* subset of the mode of the existing descriptor.
*/
FILE_LOCK(wfp);
if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) {
FILE_UNLOCK(wfp);
FILEDESC_UNLOCK(fdp);
return (EACCES);
}
fp = fdp->fd_ofiles[indx];
#if 0
if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED)
(void) munmapfd(td, indx);
#endif
fdp->fd_ofiles[indx] = wfp;
fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
fhold_locked(wfp);
FILE_UNLOCK(wfp);
if (indx > fdp->fd_lastfile)
fdp->fd_lastfile = indx;
if (fp != NULL)
FILE_LOCK(fp);
FILEDESC_UNLOCK(fdp);
/*
* we now own the reference to fp that the ofiles[] array
* used to own. Release it.
*/
if (fp != NULL)
fdrop_locked(fp, td);
return (0);
case ENXIO:
/*
* Steal away the file pointer from dfd, and stuff it into indx.
*/
fp = fdp->fd_ofiles[indx];
#if 0
if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED)
(void) munmapfd(td, indx);
#endif
fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
fdp->fd_ofiles[dfd] = NULL;
fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
fdp->fd_ofileflags[dfd] = 0;
/*
* Complete the clean up of the filedesc structure by
* recomputing the various hints.
*/
if (indx > fdp->fd_lastfile) {
fdp->fd_lastfile = indx;
} else {
while (fdp->fd_lastfile > 0 &&
fdp->fd_ofiles[fdp->fd_lastfile] == NULL) {
fdp->fd_lastfile--;
}
if (dfd < fdp->fd_freefile)
fdp->fd_freefile = dfd;
}
if (fp != NULL)
FILE_LOCK(fp);
FILEDESC_UNLOCK(fdp);
/*
* we now own the reference to fp that the ofiles[] array
* used to own. Release it.
*/
if (fp != NULL)
fdrop_locked(fp, td);
return (0);
default:
FILEDESC_UNLOCK(fdp);
return (error);
}
/* NOTREACHED */
}
/*
* Get file structures.
*/
static int
sysctl_kern_file(SYSCTL_HANDLER_ARGS)
{
int error;
struct file *fp;
sx_slock(&filelist_lock);
if (!req->oldptr) {
/*
* overestimate by 10 files
*/
error = SYSCTL_OUT(req, 0, sizeof(filehead) +
(nfiles + 10) * sizeof(struct file));
sx_sunlock(&filelist_lock);
return (error);
}
error = SYSCTL_OUT(req, (caddr_t)&filehead, sizeof(filehead));
if (error) {
sx_sunlock(&filelist_lock);
return (error);
}
/*
* followed by an array of file structures
*/
LIST_FOREACH(fp, &filehead, f_list) {
error = SYSCTL_OUT(req, (caddr_t)fp, sizeof (struct file));
if (error) {
sx_sunlock(&filelist_lock);
return (error);
}
}
sx_sunlock(&filelist_lock);
return (0);
}
SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
0, 0, sysctl_kern_file, "S,file", "Entire file table");
SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
&maxfilesperproc, 0, "Maximum files allowed open per process");
SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
&maxfiles, 0, "Maximum number of files");
SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
&nfiles, 0, "System-wide number of open files");
static void
fildesc_drvinit(void *unused)
{
dev_t dev;
dev = make_dev(&fildesc_cdevsw, 0, UID_BIN, GID_BIN, 0666, "fd/0");
make_dev_alias(dev, "stdin");
dev = make_dev(&fildesc_cdevsw, 1, UID_BIN, GID_BIN, 0666, "fd/1");
make_dev_alias(dev, "stdout");
dev = make_dev(&fildesc_cdevsw, 2, UID_BIN, GID_BIN, 0666, "fd/2");
make_dev_alias(dev, "stderr");
if (!devfs_present) {
int fd;
for (fd = 3; fd < NUMFDESC; fd++)
make_dev(&fildesc_cdevsw, fd, UID_BIN, GID_BIN, 0666,
"fd/%d", fd);
}
}
struct fileops badfileops = {
badfo_readwrite,
badfo_readwrite,
badfo_ioctl,
badfo_poll,
badfo_kqfilter,
badfo_stat,
badfo_close
};
static int
badfo_readwrite(fp, uio, cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *cred;
struct thread *td;
int flags;
{
return (EBADF);
}
static int
badfo_ioctl(fp, com, data, td)
struct file *fp;
u_long com;
caddr_t data;
struct thread *td;
{
return (EBADF);
}
static int
badfo_poll(fp, events, cred, td)
struct file *fp;
int events;
struct ucred *cred;
struct thread *td;
{
return (0);
}
static int
badfo_kqfilter(fp, kn)
struct file *fp;
struct knote *kn;
{
return (0);
}
static int
badfo_stat(fp, sb, td)
struct file *fp;
struct stat *sb;
struct thread *td;
{
return (EBADF);
}
static int
badfo_close(fp, td)
struct file *fp;
struct thread *td;
{
return (EBADF);
}
SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,
fildesc_drvinit,NULL)
static void filelistinit __P((void *));
SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL)
/* ARGSUSED*/
static void
filelistinit(dummy)
void *dummy;
{
sx_init(&filelist_lock, "filelist lock");
}
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