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44404e4547
freebsd-skq/sys/kern/kern_descrip.c
rwatson 44404e4547 In order to better support flexible and extensible access control, 
make a series of modifications to the credential arguments relating
to file read and write operations to cliarfy which credential is
used for what:

- Change fo_read() and fo_write() to accept "active_cred" instead of
  "cred", and change the semantics of consumers of fo_read() and
  fo_write() to pass the active credential of the thread requesting
  an operation rather than the cached file cred.  The cached file
  cred is still available in fo_read() and fo_write() consumers
  via fp->f_cred.  These changes largely in sys_generic.c.

For each implementation of fo_read() and fo_write(), update cred
usage to reflect this change and maintain current semantics:

- badfo_readwrite() unchanged
- kqueue_read/write() unchanged
  pipe_read/write() now authorize MAC using active_cred rather
  than td->td_ucred
- soo_read/write() unchanged
- vn_read/write() now authorize MAC using active_cred but
  VOP_READ/WRITE() with fp->f_cred

Modify vn_rdwr() to accept two credential arguments instead of a
single credential: active_cred and file_cred.  Use active_cred
for MAC authorization, and select a credential for use in
VOP_READ/WRITE() based on whether file_cred is NULL or not.  If
file_cred is provided, authorize the VOP using that cred,
otherwise the active credential, matching current semantics.

Modify current vn_rdwr() consumers to pass a file_cred if used
in the context of a struct file, and to always pass active_cred.
When vn_rdwr() is used without a file_cred, pass NOCRED.

These changes should maintain current semantics for read/write,
but avoid a redundant passing of fp->f_cred, as well as making
it more clear what the origin of each credential is in file
descriptor read/write operations.

Follow-up commits will make similar changes to other file descriptor
operations, and modify the MAC framework to pass both credentials
to MAC policy modules so they can implement either semantic for
revocation.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-15 20:55:08 +00:00

2227 lines
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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/namei.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 <sys/signalvar.h>
#include <machine/limits.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table");
static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
uma_zone_t file_zone;
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(struct filedesc *fdp, int old, int new, register_t *retval,
struct thread *td);
static int badfo_readwrite(struct file *fp, struct uio *uio,
struct ucred *active_cred, int flags, struct thread *td);
static int badfo_ioctl(struct file *fp, u_long com, void *data,
struct thread *td);
static int badfo_poll(struct file *fp, int events,
struct ucred *cred, struct thread *td);
static int badfo_kqfilter(struct file *fp, struct knote *kn);
static int badfo_stat(struct file *fp, struct stat *sb, struct thread *td);
static int badfo_close(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 */
struct mtx sigio_lock; /* mtx to protect pointers to sigio */
/*
* 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);
}
/*
* 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 & UF_EXCLOSE) ? FD_CLOEXEC : 0;
FILEDESC_UNLOCK(fdp);
break;
case F_SETFD:
*pop = (*pop &~ UF_EXCLOSE) |
(uap->arg & FD_CLOEXEC ? UF_EXCLOSE : 0);
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, &tmp, td);
if (error) {
fdrop(fp, td);
break;
}
tmp = fp->f_flag & FASYNC;
error = fo_ioctl(fp, FIOASYNC, &tmp, td);
if (!error) {
fdrop(fp, td);
break;
}
fp->f_flag &= ~FNONBLOCK;
tmp = 0;
(void)fo_ioctl(fp, FIONBIO, &tmp, td);
fdrop(fp, td);
break;
case F_GETOWN:
fhold(fp);
FILEDESC_UNLOCK(fdp);
error = fo_ioctl(fp, FIOGETOWN, (void *)td->td_retval, td);
fdrop(fp, td);
break;
case F_SETOWN:
fhold(fp);
FILEDESC_UNLOCK(fdp);
error = fo_ioctl(fp, FIOSETOWN, &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, &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, &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(&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(sigiop)
struct sigio **sigiop;
{
struct sigio *sigio;
SIGIO_LOCK();
sigio = *sigiop;
if (sigio == NULL) {
SIGIO_UNLOCK();
return;
}
*(sigio->sio_myref) = NULL;
if ((sigio)->sio_pgid < 0) {
struct pgrp *pg = (sigio)->sio_pgrp;
PGRP_LOCK(pg);
SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
sigio, sio_pgsigio);
PGRP_UNLOCK(pg);
} else {
struct proc *p = (sigio)->sio_proc;
PROC_LOCK(p);
SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
sigio, sio_pgsigio);
PROC_UNLOCK(p);
}
SIGIO_UNLOCK();
crfree(sigio->sio_ucred);
FREE(sigio, M_SIGIO);
}
/*
* Free a list of sigio structures.
* We only need to lock the SIGIO_LOCK because we have made ourselves
* inaccessable to callers of fsetown and therefore do not need to lock
* the proc or pgrp struct for the list manipulation.
*/
void
funsetownlst(sigiolst)
struct sigiolst *sigiolst;
{
struct sigio *sigio;
struct proc *p;
struct pgrp *pg;
sigio = SLIST_FIRST(sigiolst);
if (sigio == NULL)
return;
p = NULL;
pg = NULL;
/*
* Every entry of the list should belong
* to a single proc or pgrp.
*/
if (sigio->sio_pgid < 0) {
pg = sigio->sio_pgrp;
PGRP_LOCK_ASSERT(pg, MA_NOTOWNED);
} else /* if (sigio->sio_pgid > 0) */ {
p = sigio->sio_proc;
PROC_LOCK_ASSERT(p, MA_NOTOWNED);
}
SIGIO_LOCK();
while ((sigio = SLIST_FIRST(sigiolst)) != NULL) {
*(sigio->sio_myref) = NULL;
if (pg != NULL) {
KASSERT(sigio->sio_pgid < 0,
("Proc sigio in pgrp sigio list"));
KASSERT(sigio->sio_pgrp == pg,
("Bogus pgrp in sigio list"));
PGRP_LOCK(pg);
SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio,
sio_pgsigio);
PGRP_UNLOCK(pg);
} else /* if (p != NULL) */ {
KASSERT(sigio->sio_pgid > 0,
("Pgrp sigio in proc sigio list"));
KASSERT(sigio->sio_proc == p,
("Bogus proc in sigio list"));
PROC_LOCK(p);
SLIST_REMOVE(&p->p_sigiolst, sigio, sigio,
sio_pgsigio);
PROC_UNLOCK(p);
}
SIGIO_UNLOCK();
crfree(sigio->sio_ucred);
FREE(sigio, M_SIGIO);
SIGIO_LOCK();
}
SIGIO_UNLOCK();
}
/*
* 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 ret;
if (pgid == 0) {
funsetown(sigiop);
return (0);
}
ret = 0;
/* Allocate and fill in the new sigio out of locks. */
MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK);
sigio->sio_pgid = pgid;
sigio->sio_ucred = crhold(curthread->td_ucred);
sigio->sio_myref = sigiop;
sx_slock(&proctree_lock);
if (pgid > 0) {
proc = pfind(pgid);
if (proc == NULL) {
ret = ESRCH;
goto fail;
}
/*
* 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.
*/
PROC_UNLOCK(proc);
if (proc->p_session != curthread->td_proc->p_session) {
ret = EPERM;
goto fail;
}
pgrp = NULL;
} else /* if (pgid < 0) */ {
pgrp = pgfind(-pgid);
if (pgrp == NULL) {
ret = ESRCH;
goto fail;
}
PGRP_UNLOCK(pgrp);
/*
* 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) {
ret = EPERM;
goto fail;
}
proc = NULL;
}
funsetown(sigiop);
if (pgid > 0) {
PROC_LOCK(proc);
/*
* since funsetownlst() is called without the proctree
* locked we need to check for P_WEXIT.
* XXX: is ESRCH correct?
*/
if ((proc->p_flag & P_WEXIT) != 0) {
PROC_UNLOCK(proc);
ret = ESRCH;
goto fail;
}
SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
sigio->sio_proc = proc;
PROC_UNLOCK(proc);
} else {
PGRP_LOCK(pgrp);
SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
sigio->sio_pgrp = pgrp;
PGRP_UNLOCK(pgrp);
}
sx_sunlock(&proctree_lock);
SIGIO_LOCK();
*sigiop = sigio;
SIGIO_UNLOCK();
return (0);
fail:
sx_sunlock(&proctree_lock);
crfree(sigio->sio_ucred);
FREE(sigio, M_SIGIO);
return (ret);
}
/*
* 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(&oub, 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(&ub, 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;
mtx_lock(&Giant);
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
error = fo_stat(fp, &ub, td);
if (error == 0) {
cvtnstat(&ub, &nub);
error = copyout(&nub, 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) {
FILEDESC_UNLOCK(fdp);
mtx_lock(&Giant);
FREE(oldofile, M_FILEDESC);
mtx_unlock(&Giant);
FILEDESC_LOCK(fdp);
}
}
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;
fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO);
sx_xlock(&filelist_lock);
if (nfiles >= maxfiles) {
sx_xunlock(&filelist_lock);
uma_zfree(file_zone, fp);
tablefull("file");
return (ENFILE);
}
nfiles++;
/*
* If the process has file descriptor zero open, add the new file
* descriptor to the list of open files at that point, otherwise
* put it at the front of the list of open files.
*/
FILEDESC_LOCK(p->p_fd);
if ((error = fdalloc(td, 0, &i))) {
FILEDESC_UNLOCK(p->p_fd);
nfiles--;
sx_xunlock(&filelist_lock);
uma_zfree(file_zone, fp);
return (error);
}
fp->f_mtxp = mtx_pool_alloc();
fp->f_gcflag = 0;
fp->f_count = 1;
fp->f_cred = crhold(td->td_ucred);
fp->f_ops = &badfileops;
fp->f_seqcount = 1;
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);
uma_zfree(file_zone, fp);
}
/*
* 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_LOCK_DESC, NULL, 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_LOCK_DESC, NULL, 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;
struct file **fpp;
register int i;
fdp = td->td_proc->p_fd;
/* 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);
}
PROC_LOCK(td->td_proc);
td->td_proc->p_fd = NULL;
PROC_UNLOCK(td->td_proc);
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 filesystems 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);
}
/*
* It is unsafe for set[ug]id processes to be started with file
* descriptors 0..2 closed, as these descriptors are given implicit
* significance in the Standard C library. fdcheckstd() will create a
* descriptor referencing /dev/null for each of stdin, stdout, and
* stderr that is not already open.
*/
int
fdcheckstd(td)
struct thread *td;
{
struct nameidata nd;
struct filedesc *fdp;
struct file *fp;
register_t retval;
int fd, i, error, flags, devnull;
fdp = td->td_proc->p_fd;
if (fdp == NULL)
return (0);
devnull = -1;
error = 0;
for (i = 0; i < 3; i++) {
if (fdp->fd_ofiles[i] != NULL)
continue;
if (devnull < 0) {
error = falloc(td, &fp, &fd);
if (error != 0)
break;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/null",
td);
flags = FREAD | FWRITE;
error = vn_open(&nd, &flags, 0);
if (error != 0) {
FILEDESC_LOCK(fdp);
fdp->fd_ofiles[i] = NULL;
FILEDESC_UNLOCK(fdp);
fdrop(fp, td);
break;
}
NDFREE(&nd, NDF_ONLY_PNBUF);
fp->f_data = nd.ni_vp;
fp->f_flag = flags;
fp->f_ops = &vnops;
fp->f_type = DTYPE_VNODE;
VOP_UNLOCK(nd.ni_vp, 0, td);
devnull = fd;
} else {
FILEDESC_LOCK(fdp);
error = fdalloc(td, 0, &fd);
if (error != 0) {
FILEDESC_UNLOCK(fdp);
break;
}
error = do_dup(fdp, devnull, fd, &retval, td);
if (error != 0)
break;
}
}
return (error);
}
/*
* 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 ((fp = fget_locked(fdp, 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);
}
mtx_lock(&Giant);
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);
mtx_unlock(&Giant);
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)
{
struct proc *p;
struct filedesc *fdp;
struct file *fp;
struct xfile xf;
int error, n;
sysctl_wire_old_buffer(req, 0);
if (!req->oldptr) {
n = 16; /* slight overestimate */
sx_slock(&filelist_lock);
LIST_FOREACH(fp, &filehead, f_list) {
/*
* We should grab the lock, but this is an
* estimate, so does it really matter?
*/
/* mtx_lock(fp->f_mtxp); */
n += fp->f_count;
/* mtx_unlock(f->f_mtxp); */
}
sx_sunlock(&filelist_lock);
return (SYSCTL_OUT(req, 0, n * sizeof xf));
}
error = 0;
bzero(&xf, sizeof xf);
xf.xf_size = sizeof xf;
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
PROC_LOCK(p);
xf.xf_pid = p->p_pid;
xf.xf_uid = p->p_ucred->cr_uid;
if ((fdp = p->p_fd) == NULL) {
PROC_UNLOCK(p);
continue;
}
FILEDESC_LOCK(fdp);
for (n = 0; n < fdp->fd_nfiles; ++n) {
if ((fp = fdp->fd_ofiles[n]) == NULL)
continue;
xf.xf_fd = n;
xf.xf_file = fp;
#define XF_COPY(field) xf.xf_##field = fp->f_##field
XF_COPY(type);
XF_COPY(count);
XF_COPY(msgcount);
XF_COPY(offset);
XF_COPY(data);
XF_COPY(flag);
#undef XF_COPY
error = SYSCTL_OUT(req, &xf, sizeof xf);
if (error)
break;
}
FILEDESC_UNLOCK(fdp);
PROC_UNLOCK(p);
if (error)
break;
}
sx_sunlock(&allproc_lock);
return (error);
}
SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
0, 0, sysctl_kern_file, "S,xfile", "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, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
return (EBADF);
}
static int
badfo_ioctl(fp, com, data, td)
struct file *fp;
u_long com;
void *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(void *);
SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL)
/* ARGSUSED*/
static void
filelistinit(dummy)
void *dummy;
{
file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, 0);
sx_init(&filelist_lock, "filelist lock");
mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF);
}
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