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freebsd-dev/sys/kern/kern_descrip.c
John Baldwin 5fc3031366 - Change falloc() to acquire an fd from the process table last so that 
it can do it w/o needing to hold the filelist_lock sx lock.
- fdalloc() doesn't need Giant to call free() anymore.  It also doesn't
  need to drop and reacquire the filedesc lock around free() now as a
  result.
- Try to make the code that copies fd tables when extending the fd table in
  fdalloc() a bit more readable by performing assignments in separate
  statements.  This is still a bit ugly though.
- Use max() instead of an if statement so to figure out the starting point
  in the search-for-a-free-fd loop in fdalloc() so it reads better next to
  the min() in the previous line.
- Don't grow nfiles in steps up to the size needed if we dup2() to some
  really large number.  Go ahead and double 'nfiles' in a loop prior
  to doing the malloc().
- malloc() doesn't need Giant now.
- Use malloc() and free() instead of MALLOC() and FREE() in fdalloc().
- Check to see if the size we are going to grow to is too big, not if the
  current size of the fd table is too big in the loop in fdalloc().  This
  means if we are out of space or if dup2() requests too high of a fd,
  then we will return an error before we go off and try to allocate some
  huge table and copy the existing table into it.
- Move all of the logic for dup'ing a file descriptor into do_dup() instead
  of putting some of it in do_dup() and duplicating other parts in four
  different places.  This makes dup(), dup2(), and fcntl(F_DUPFD) basically
  wrappers of do_dup now.  fcntl() still has an extra check since it uses
  a different error return value in one case then the other functions.
- Add a KASSERT() for an assertion that may not always be true where the
  fdcheckstd() function assumes that falloc() returns the fd requested and
  not some other fd.  I think that the assertion is always true because we
  are always single-threaded when we get to this point, but if one was
  using rfork() and another process sharing the fd table were playing with
  the fd table, there might could be a problem.
- To handle the problem of a file descriptor we are dup()'ing being closed
  out from under us in dup() in general, do_dup() now obtains a reference
  on the file in question before calling fdalloc().  If after the call to
  fdalloc() the file for the fd we are dup'ing is a different file, then
  we drop our reference on the original file and return EBADF.  This
  race was only handled in the dup2() case before and would just retry
  the operation.  The error return allows the user to know they are being
  stupid since they have a locking bug in their app instead of dup'ing
  some other descriptor and returning it to them.

Tested on:	i386, alpha, sparc64
2002-09-03 20:16:31 +00:00

2243 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/syscallsubr.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,
};
/* How to treat 'new' parameter when allocating a fd for do_dup(). */
enum dup_type { DUP_VARIABLE, DUP_FIXED };
static int do_dup(struct thread *td, enum dup_type type, int old, int new,
register_t *retval);
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 ucred *active_cred, struct thread *td);
static int badfo_poll(struct file *fp, int events,
struct ucred *active_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 ucred *active_cred, 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;
{
return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to,
td->td_retval));
}
/*
* 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;
{
return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval));
}
/*
* 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;
{
struct flock fl;
intptr_t arg;
int error;
error = 0;
switch (uap->cmd) {
case F_SETLK:
case F_GETLK:
error = copyin((caddr_t)(intptr_t)uap->arg, &fl, sizeof(fl));
arg = (intptr_t)&fl;
break;
default:
arg = uap->arg;
break;
}
if (error)
return (error);
error = kern_fcntl(td, uap->fd, uap->cmd, arg);
if (error)
return (error);
switch (uap->cmd) {
case F_GETLK:
error = copyout(&fl, (caddr_t)(intptr_t)uap->arg, sizeof(fl));
break;
}
return (error);
}
int
kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
{
register struct proc *p = td->td_proc;
register struct filedesc *fdp;
register struct file *fp;
register char *pop;
struct vnode *vp;
struct flock *flp;
int tmp, error = 0, flg = F_POSIX;
u_int newmin;
struct proc *leaderp;
mtx_lock(&Giant);
fdp = p->p_fd;
FILEDESC_LOCK(fdp);
if ((unsigned)fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[fd]) == NULL) {
FILEDESC_UNLOCK(fdp);
error = EBADF;
goto done2;
}
pop = &fdp->fd_ofileflags[fd];
switch (cmd) {
case F_DUPFD:
FILEDESC_UNLOCK(fdp);
newmin = arg;
if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
newmin >= maxfilesperproc) {
error = EINVAL;
break;
}
error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval);
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) |
(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(arg & ~O_ACCMODE) & FCNTLFLAGS;
tmp = fp->f_flag & FNONBLOCK;
error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
if (error) {
fdrop(fp, td);
break;
}
tmp = fp->f_flag & FASYNC;
error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td);
if (!error) {
fdrop(fp, td);
break;
}
fp->f_flag &= ~FNONBLOCK;
tmp = 0;
(void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
fdrop(fp, td);
break;
case F_GETOWN:
fhold(fp);
FILEDESC_UNLOCK(fdp);
error = fo_ioctl(fp, FIOGETOWN, (void *)td->td_retval,
td->td_ucred, td);
fdrop(fp, td);
break;
case F_SETOWN:
fhold(fp);
FILEDESC_UNLOCK(fdp);
error = fo_ioctl(fp, FIOSETOWN, &arg, td->td_ucred, td);
fdrop(fp, td);
break;
case F_SETLKW:
flg |= F_WAIT;
/* FALLTHROUGH F_SETLK */
case F_SETLK:
if (fp->f_type != DTYPE_VNODE) {
FILEDESC_UNLOCK(fdp);
error = EBADF;
break;
}
flp = (struct flock *)arg;
if (flp->l_whence == SEEK_CUR) {
if (fp->f_offset < 0 ||
(flp->l_start > 0 &&
fp->f_offset > OFF_MAX - flp->l_start)) {
FILEDESC_UNLOCK(fdp);
error = EOVERFLOW;
break;
}
flp->l_start += fp->f_offset;
}
/*
* lockop may block
*/
fhold(fp);
FILEDESC_UNLOCK(fdp);
vp = (struct vnode *)fp->f_data;
switch (flp->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,
flp, 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, flp,
flg);
break;
case F_UNLCK:
PROC_LOCK(p);
leaderp = p->p_leader;
PROC_UNLOCK(p);
error = VOP_ADVLOCK(vp, (caddr_t)leaderp, F_UNLCK, flp,
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;
}
flp = (struct flock *)arg;
if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK &&
flp->l_type != F_UNLCK) {
FILEDESC_UNLOCK(fdp);
error = EINVAL;
break;
}
if (flp->l_whence == SEEK_CUR) {
if ((flp->l_start > 0 &&
fp->f_offset > OFF_MAX - flp->l_start) ||
(flp->l_start < 0 &&
fp->f_offset < OFF_MIN - flp->l_start)) {
FILEDESC_UNLOCK(fdp);
error = EOVERFLOW;
break;
}
flp->l_start += fp->f_offset;
}
/*
* lockop may block
*/
fhold(fp);
FILEDESC_UNLOCK(fdp);
vp = (struct vnode *)fp->f_data;
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp,
F_POSIX);
fdrop(fp, td);
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(td, type, old, new, retval)
enum dup_type type;
int old, new;
register_t *retval;
struct thread *td;
{
register struct filedesc *fdp;
struct proc *p;
struct file *fp;
struct file *delfp;
int error, newfd;
p = td->td_proc;
fdp = p->p_fd;
/*
* Verify we have a valid descriptor to dup from and possibly to
* dup to.
*/
FILEDESC_LOCK(fdp);
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 (type == DUP_FIXED && old == new) {
*retval = new;
FILEDESC_UNLOCK(fdp);
return (0);
}
fp = fdp->fd_ofiles[old];
fhold(fp);
/*
* Expand the table for the new descriptor if needed. This may
* block and drop and reacquire the filedesc lock.
*/
if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) {
error = fdalloc(td, new, &newfd);
if (error) {
FILEDESC_UNLOCK(fdp);
return (error);
}
}
if (type == DUP_VARIABLE)
new = newfd;
/*
* If the old file changed out from under us then treat it as a
* bad file descriptor. Userland should do its own locking to
* avoid this case.
*/
if (fdp->fd_ofiles[old] != fp) {
if (fdp->fd_ofiles[new] == NULL) {
if (new < fdp->fd_freefile)
fdp->fd_freefile = new;
while (fdp->fd_lastfile > 0 &&
fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
fdp->fd_lastfile--;
}
FILEDESC_UNLOCK(fdp);
fdrop(fp, td);
return (EBADF);
}
KASSERT(old != new, ("new fd is same as old"));
/*
* 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];
KASSERT(delfp == NULL || type == DUP_FIXED,
("dup() picked an open file"));
#if 0
if (delfp && (fdp->fd_ofileflags[new] & UF_MAPPED))
(void) munmapfd(td, new);
#endif
/*
* Duplicate the source descriptor, update lastfile
*/
fdp->fd_ofiles[new] = fp;
fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
if (new > fdp->fd_lastfile)
fdp->fd_lastfile = new;
FILEDESC_UNLOCK(fdp);
*retval = new;
/*
* 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->td_ucred, 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->td_ucred, 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->td_ucred, 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);
i = max(want, 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 (i >= lim)
return (EMFILE);
if (fdp->fd_nfiles < NDEXTENT)
nfiles = NDEXTENT;
else
nfiles = 2 * fdp->fd_nfiles;
while (nfiles < want)
nfiles <<= 1;
FILEDESC_UNLOCK(fdp);
newofile = malloc(nfiles * OFILESIZE, M_FILEDESC, M_WAITOK);
/*
* Deal with file-table extend race that might have
* occurred while filedesc was unlocked.
*/
FILEDESC_LOCK(fdp);
if (fdp->fd_nfiles >= nfiles) {
free(newofile, M_FILEDESC);
continue;
}
newofileflags = (char *) &newofile[nfiles];
/*
* Copy the existing ofile and ofileflags arrays
* and zero the new portion of each array.
*/
i = fdp->fd_nfiles * sizeof(struct file *);
bcopy(fdp->fd_ofiles, newofile, i);
bzero((char *)newofile + i,
nfiles * sizeof(struct file *) - i);
i = fdp->fd_nfiles * sizeof(char);
bcopy(fdp->fd_ofileflags, newofileflags, i);
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)
free(oldofile, M_FILEDESC);
}
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.
*/
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;
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);
}
sx_xunlock(&filelist_lock);
if ((error = fdalloc(td, 0, &i))) {
FILEDESC_UNLOCK(p->p_fd);
fdrop(fp, td);
return (error);
}
p->p_fd->fd_ofiles[i] = fp;
FILEDESC_UNLOCK(p->p_fd);
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;
KASSERT(fd == i, ("oof, we didn't get our fd"));
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[fd] = 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 {
error = do_dup(td, DUP_FIXED, devnull, i, &retval);
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, active_cred, td)
struct file *fp;
u_long com;
void *data;
struct ucred *active_cred;
struct thread *td;
{
return (EBADF);
}
static int
badfo_poll(fp, events, active_cred, td)
struct file *fp;
int events;
struct ucred *active_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, active_cred, td)
struct file *fp;
struct stat *sb;
struct ucred *active_cred;
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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