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27c775d7bf
freebsd-dev/sys/kern/kern_descrip.c
Robert Watson b1fc0ec1a7 o Merge contents of struct pcred into struct ucred. Specifically, add the 
real uid, saved uid, real gid, and saved gid to ucred, as well as the
  pcred->pc_uidinfo, which was associated with the real uid, only rename
  it to cr_ruidinfo so as not to conflict with cr_uidinfo, which
  corresponds to the effective uid.
o Remove p_cred from struct proc; add p_ucred to struct proc, replacing
  original macro that pointed.
  p->p_ucred to p->p_cred->pc_ucred.
o Universally update code so that it makes use of ucred instead of pcred,
  p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo,
  cr_{r,sv}{u,g}id instead of p_*, etc.
o Remove pcred0 and its initialization from init_main.c; initialize
  cr_ruidinfo there.
o Restruction many credential modification chunks to always crdup while
  we figure out locking and optimizations; generally speaking, this
  means moving to a structure like this:
        newcred = crdup(oldcred);
        ...
        p->p_ucred = newcred;
        crfree(oldcred);
  It's not race-free, but better than nothing.  There are also races
  in sys_process.c, all inter-process authorization, fork, exec, and
  exit.
o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid;
  remove comments indicating that the old arrangement was a problem.
o Restructure exec1() a little to use newcred/oldcred arrangement, and
  use improved uid management primitives.
o Clean up exit1() so as to do less work in credential cleanup due to
  pcred removal.
o Clean up fork1() so as to do less work in credential cleanup and
  allocation.
o Clean up ktrcanset() to take into account changes, and move to using
  suser_xxx() instead of performing a direct uid==0 comparision.
o Improve commenting in various kern_prot.c credential modification
  calls to better document current behavior.  In a couple of places,
  current behavior is a little questionable and we need to check
  POSIX.1 to make sure it's "right".  More commenting work still
  remains to be done.
o Update credential management calls, such as crfree(), to take into
  account new ruidinfo reference.
o Modify or add the following uid and gid helper routines:
      change_euid()
      change_egid()
      change_ruid()
      change_rgid()
      change_svuid()
      change_svgid()
  In each case, the call now acts on a credential not a process, and as
  such no longer requires more complicated process locking/etc.  They
  now assume the caller will do any necessary allocation of an
  exclusive credential reference.  Each is commented to document its
  reference requirements.
o CANSIGIO() is simplified to require only credentials, not processes
  and pcreds.
o Remove lots of (p_pcred==NULL) checks.
o Add an XXX to authorization code in nfs_lock.c, since it's
  questionable, and needs to be considered carefully.
o Simplify posix4 authorization code to require only credentials, not
  processes and pcreds.  Note that this authorization, as well as
  CANSIGIO(), needs to be updated to use the p_cansignal() and
  p_cansched() centralized authorization routines, as they currently
  do not take into account some desirable restrictions that are handled
  by the centralized routines, as well as being inconsistent with other
  similar authorization instances.
o Update libkvm to take these changes into account.

Obtained from:	TrustedBSD Project
Reviewed by:	green, bde, jhb, freebsd-arch, freebsd-audit
2001-05-25 16:59:11 +00:00

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/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94
* $FreeBSD$
*/
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/conf.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <sys/resourcevar.h>
#include <sys/event.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table");
MALLOC_DEFINE(M_FILE, "file", "Open file structure");
static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
static d_open_t fdopen;
#define NUMFDESC 64
#define CDEV_MAJOR 22
static struct cdevsw fildesc_cdevsw = {
/* open */ fdopen,
/* close */ noclose,
/* read */ noread,
/* write */ nowrite,
/* ioctl */ noioctl,
/* poll */ nopoll,
/* mmap */ nommap,
/* strategy */ nostrategy,
/* name */ "FD",
/* maj */ CDEV_MAJOR,
/* dump */ nodump,
/* psize */ nopsize,
/* flags */ 0,
};
static int do_dup __P((struct filedesc *fdp, int old, int new, register_t *retval, struct proc *p));
static int badfo_readwrite __P((struct file *fp, struct uio *uio,
struct ucred *cred, int flags, struct proc *p));
static int badfo_ioctl __P((struct file *fp, u_long com, caddr_t data,
struct proc *p));
static int badfo_poll __P((struct file *fp, int events,
struct ucred *cred, struct proc *p));
static int badfo_kqfilter __P((struct file *fp, struct knote *kn));
static int badfo_stat __P((struct file *fp, struct stat *sb, struct proc *p));
static int badfo_close __P((struct file *fp, struct proc *p));
/*
* Descriptor management.
*/
struct filelist filehead; /* head of list of open files */
int nfiles; /* actual number of open files */
extern int cmask;
/*
* System calls on descriptors.
*/
#ifndef _SYS_SYSPROTO_H_
struct getdtablesize_args {
int dummy;
};
#endif
/* ARGSUSED */
int
getdtablesize(p, uap)
struct proc *p;
struct getdtablesize_args *uap;
{
p->p_retval[0] =
min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
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
/* ARGSUSED */
int
dup2(p, uap)
struct proc *p;
struct dup2_args *uap;
{
register struct filedesc *fdp = p->p_fd;
register u_int old = uap->from, new = uap->to;
int i, error;
retry:
if (old >= fdp->fd_nfiles ||
fdp->fd_ofiles[old] == NULL ||
new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
new >= maxfilesperproc) {
return (EBADF);
}
if (old == new) {
p->p_retval[0] = new;
return (0);
}
if (new >= fdp->fd_nfiles) {
if ((error = fdalloc(p, new, &i)))
return (error);
if (new != i)
panic("dup2: fdalloc");
/*
* fdalloc() may block, retest everything.
*/
goto retry;
}
return (do_dup(fdp, (int)old, (int)new, p->p_retval, p));
}
/*
* Duplicate a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct dup_args {
u_int fd;
};
#endif
/* ARGSUSED */
int
dup(p, uap)
struct proc *p;
struct dup_args *uap;
{
register struct filedesc *fdp;
u_int old;
int new, error;
old = uap->fd;
fdp = p->p_fd;
if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL)
return (EBADF);
if ((error = fdalloc(p, 0, &new)))
return (error);
return (do_dup(fdp, (int)old, new, p->p_retval, p));
}
/*
* The file control system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct fcntl_args {
int fd;
int cmd;
long arg;
};
#endif
/* ARGSUSED */
int
fcntl(p, uap)
struct proc *p;
register struct fcntl_args *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
register char *pop;
struct vnode *vp;
int i, tmp, error, flg = F_POSIX;
struct flock fl;
u_int newmin;
if ((unsigned)uap->fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL)
return (EBADF);
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)
return (EINVAL);
if ((error = fdalloc(p, newmin, &i)))
return (error);
return (do_dup(fdp, uap->fd, i, p->p_retval, p));
case F_GETFD:
p->p_retval[0] = *pop & 1;
return (0);
case F_SETFD:
*pop = (*pop &~ 1) | (uap->arg & 1);
return (0);
case F_GETFL:
p->p_retval[0] = OFLAGS(fp->f_flag);
return (0);
case F_SETFL:
fhold(fp);
fp->f_flag &= ~FCNTLFLAGS;
fp->f_flag |= FFLAGS(uap->arg & ~O_ACCMODE) & FCNTLFLAGS;
tmp = fp->f_flag & FNONBLOCK;
error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, p);
if (error) {
fdrop(fp, p);
return (error);
}
tmp = fp->f_flag & FASYNC;
error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, p);
if (!error) {
fdrop(fp, p);
return (0);
}
fp->f_flag &= ~FNONBLOCK;
tmp = 0;
(void)fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, p);
fdrop(fp, p);
return (error);
case F_GETOWN:
fhold(fp);
error = fo_ioctl(fp, FIOGETOWN, (caddr_t)p->p_retval, p);
fdrop(fp, p);
return(error);
case F_SETOWN:
fhold(fp);
error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&uap->arg, p);
fdrop(fp, p);
return(error);
case F_SETLKW:
flg |= F_WAIT;
/* Fall into F_SETLK */
case F_SETLK:
if (fp->f_type != DTYPE_VNODE)
return (EBADF);
vp = (struct vnode *)fp->f_data;
/*
* copyin/lockop may block
*/
fhold(fp);
/* Copy in the lock structure */
error = copyin((caddr_t)(intptr_t)uap->arg, (caddr_t)&fl,
sizeof(fl));
if (error) {
fdrop(fp, p);
return (error);
}
if (fl.l_whence == SEEK_CUR)
fl.l_start += fp->f_offset;
switch (fl.l_type) {
case F_RDLCK:
if ((fp->f_flag & FREAD) == 0) {
error = EBADF;
break;
}
p->p_flag |= P_ADVLOCK;
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
&fl, flg);
break;
case F_WRLCK:
if ((fp->f_flag & FWRITE) == 0) {
error = EBADF;
break;
}
p->p_flag |= P_ADVLOCK;
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
&fl, flg);
break;
case F_UNLCK:
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
&fl, F_POSIX);
break;
default:
error = EINVAL;
break;
}
fdrop(fp, p);
return(error);
case F_GETLK:
if (fp->f_type != DTYPE_VNODE)
return (EBADF);
vp = (struct vnode *)fp->f_data;
/*
* copyin/lockop may block
*/
fhold(fp);
/* Copy in the lock structure */
error = copyin((caddr_t)(intptr_t)uap->arg, (caddr_t)&fl,
sizeof(fl));
if (error) {
fdrop(fp, p);
return (error);
}
if (fl.l_type != F_RDLCK && fl.l_type != F_WRLCK &&
fl.l_type != F_UNLCK) {
fdrop(fp, p);
return (EINVAL);
}
if (fl.l_whence == SEEK_CUR)
fl.l_start += fp->f_offset;
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK,
&fl, F_POSIX);
fdrop(fp, p);
if (error == 0) {
error = copyout((caddr_t)&fl,
(caddr_t)(intptr_t)uap->arg, sizeof(fl));
}
return(error);
default:
return (EINVAL);
}
/* NOTREACHED */
}
/*
* Common code for dup, dup2, and fcntl(F_DUPFD).
*/
static int
do_dup(fdp, old, new, retval, p)
register struct filedesc *fdp;
register int old, new;
register_t *retval;
struct proc *p;
{
struct file *fp;
struct file *delfp;
/*
* 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(p, 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;
/*
* 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)
(void) closef(delfp, p);
return (0);
}
/*
* If sigio is on the list associated with a process or process group,
* disable signalling from the device, remove sigio from the list and
* free sigio.
*/
void
funsetown(sigio)
struct sigio *sigio;
{
int s;
if (sigio == NULL)
return;
s = splhigh();
*(sigio->sio_myref) = NULL;
splx(s);
if (sigio->sio_pgid < 0) {
SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
sigio, sio_pgsigio);
} else /* if ((*sigiop)->sio_pgid > 0) */ {
SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
sigio, sio_pgsigio);
}
crfree(sigio->sio_ucred);
FREE(sigio, M_SIGIO);
}
/* Free a list of sigio structures. */
void
funsetownlst(sigiolst)
struct sigiolst *sigiolst;
{
struct sigio *sigio;
while ((sigio = SLIST_FIRST(sigiolst)) != NULL)
funsetown(sigio);
}
/*
* This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
*
* After permission checking, add a sigio structure to the sigio list for
* the process or process group.
*/
int
fsetown(pgid, sigiop)
pid_t pgid;
struct sigio **sigiop;
{
struct proc *proc;
struct pgrp *pgrp;
struct sigio *sigio;
int s;
if (pgid == 0) {
funsetown(*sigiop);
return (0);
}
if (pgid > 0) {
proc = pfind(pgid);
if (proc == NULL)
return (ESRCH);
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (proc->p_session != curproc->p_session) {
PROC_UNLOCK(proc);
return (EPERM);
}
PROC_UNLOCK(proc);
pgrp = NULL;
} else /* if (pgid < 0) */ {
pgrp = pgfind(-pgid);
if (pgrp == NULL)
return (ESRCH);
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (pgrp->pg_session != curproc->p_session)
return (EPERM);
proc = NULL;
}
funsetown(*sigiop);
MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK);
if (pgid > 0) {
SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
sigio->sio_proc = proc;
} else {
SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
sigio->sio_pgrp = pgrp;
}
sigio->sio_pgid = pgid;
crhold(curproc->p_ucred);
sigio->sio_ucred = curproc->p_ucred;
sigio->sio_myref = sigiop;
s = splhigh();
*sigiop = sigio;
splx(s);
return (0);
}
/*
* This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
*/
pid_t
fgetown(sigio)
struct sigio *sigio;
{
return (sigio != NULL ? sigio->sio_pgid : 0);
}
/*
* Close a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct close_args {
int fd;
};
#endif
/* ARGSUSED */
int
close(p, uap)
struct proc *p;
struct close_args *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
register int fd = uap->fd;
if ((unsigned)fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[fd]) == NULL)
return (EBADF);
#if 0
if (fdp->fd_ofileflags[fd] & UF_MAPPED)
(void) munmapfd(p, 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)
knote_fdclose(p, fd);
return (closef(fp, p));
}
#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
/* ARGSUSED */
int
ofstat(p, uap)
struct proc *p;
register struct ofstat_args *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
struct stat ub;
struct ostat oub;
int error;
if ((unsigned)uap->fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL)
return (EBADF);
fhold(fp);
error = fo_stat(fp, &ub, p);
if (error == 0) {
cvtstat(&ub, &oub);
error = copyout((caddr_t)&oub, (caddr_t)uap->sb, sizeof (oub));
}
fdrop(fp, p);
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
/* ARGSUSED */
int
fstat(p, uap)
struct proc *p;
register struct fstat_args *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
struct stat ub;
int error;
if ((unsigned)uap->fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL)
return (EBADF);
fhold(fp);
error = fo_stat(fp, &ub, p);
if (error == 0)
error = copyout((caddr_t)&ub, (caddr_t)uap->sb, sizeof (ub));
fdrop(fp, p);
return (error);
}
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct nfstat_args {
int fd;
struct nstat *sb;
};
#endif
/* ARGSUSED */
int
nfstat(p, uap)
struct proc *p;
register struct nfstat_args *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
struct stat ub;
struct nstat nub;
int error;
if ((unsigned)uap->fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL)
return (EBADF);
fhold(fp);
error = fo_stat(fp, &ub, p);
if (error == 0) {
cvtnstat(&ub, &nub);
error = copyout((caddr_t)&nub, (caddr_t)uap->sb, sizeof (nub));
}
fdrop(fp, p);
return (error);
}
/*
* Return pathconf information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct fpathconf_args {
int fd;
int name;
};
#endif
/* ARGSUSED */
int
fpathconf(p, uap)
struct proc *p;
register struct fpathconf_args *uap;
{
struct filedesc *fdp = p->p_fd;
struct file *fp;
struct vnode *vp;
int error = 0;
if ((unsigned)uap->fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL)
return (EBADF);
fhold(fp);
switch (fp->f_type) {
case DTYPE_PIPE:
case DTYPE_SOCKET:
if (uap->name != _PC_PIPE_BUF)
return (EINVAL);
p->p_retval[0] = PIPE_BUF;
error = 0;
break;
case DTYPE_FIFO:
case DTYPE_VNODE:
vp = (struct vnode *)fp->f_data;
error = VOP_PATHCONF(vp, uap->name, p->p_retval);
break;
default:
error = EOPNOTSUPP;
break;
}
fdrop(fp, p);
return(error);
}
/*
* Allocate a file descriptor for the process.
*/
static int fdexpand;
SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, "");
int
fdalloc(p, want, result)
struct proc *p;
int want;
int *result;
{
register struct filedesc *fdp = p->p_fd;
register int i;
int lim, last, nfiles;
struct file **newofile;
char *newofileflags;
/*
* 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;
MALLOC(newofile, struct file **, nfiles * OFILESIZE,
M_FILEDESC, M_WAITOK);
/*
* deal with file-table extend race that might have occured
* when malloc was blocked.
*/
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.
*/
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)
FREE(fdp->fd_ofiles, M_FILEDESC);
fdp->fd_ofiles = newofile;
fdp->fd_ofileflags = newofileflags;
fdp->fd_nfiles = nfiles;
fdexpand++;
}
return (0);
}
/*
* Check to see whether n user file descriptors
* are available to the process p.
*/
int
fdavail(p, n)
struct proc *p;
register int n;
{
register struct filedesc *fdp = p->p_fd;
register struct file **fpp;
register int i, lim, last;
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(p, resultfp, resultfd)
register struct proc *p;
struct file **resultfp;
int *resultfd;
{
register struct file *fp, *fq;
int error, i;
if (nfiles >= maxfiles) {
tablefull("file");
return (ENFILE);
}
/*
* Allocate a new file descriptor.
* If the process has file descriptor zero open, add to the list
* of open files at that point, otherwise put it at the front of
* the list of open files.
*/
nfiles++;
MALLOC(fp, struct file *, sizeof(struct file), M_FILE, M_WAITOK | M_ZERO);
/*
* wait until after malloc (which may have blocked) returns before
* allocating the slot, else a race might have shrunk it if we had
* allocated it before the malloc.
*/
if ((error = fdalloc(p, 0, &i))) {
nfiles--;
FREE(fp, M_FILE);
return (error);
}
fp->f_count = 1;
fp->f_cred = p->p_ucred;
fp->f_ops = &badfileops;
fp->f_seqcount = 1;
crhold(fp->f_cred);
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;
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!"));
LIST_REMOVE(fp, f_list);
crfree(fp->f_cred);
nfiles--;
FREE(fp, M_FILE);
}
/*
* Build a new filedesc structure.
*/
struct filedesc *
fdinit(p)
struct proc *p;
{
register struct filedesc0 *newfdp;
register struct filedesc *fdp = p->p_fd;
MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0),
M_FILEDESC, M_WAITOK | M_ZERO);
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;
return (&newfdp->fd_fd);
}
/*
* Share a filedesc structure.
*/
struct filedesc *
fdshare(p)
struct proc *p;
{
p->p_fd->fd_refcnt++;
return (p->p_fd);
}
/*
* Copy a filedesc structure.
*/
struct filedesc *
fdcopy(p)
struct proc *p;
{
register struct filedesc *newfdp, *fdp = p->p_fd;
register struct file **fpp;
register int i;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return (NULL);
MALLOC(newfdp, struct filedesc *, sizeof(struct filedesc0),
M_FILEDESC, M_WAITOK);
bcopy(fdp, newfdp, sizeof(struct filedesc));
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.
*/
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.
*/
i = newfdp->fd_nfiles;
while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
i /= 2;
MALLOC(newfdp->fd_ofiles, struct file **, i * OFILESIZE,
M_FILEDESC, M_WAITOK);
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;
for (i = newfdp->fd_lastfile; i-- >= 0; fpp++) {
if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE)
*fpp = NULL;
}
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(p)
struct proc *p;
{
register struct filedesc *fdp = p->p_fd;
struct file **fpp;
register int i;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return;
if (--fdp->fd_refcnt > 0)
return;
/*
* we are the last reference to the structure, we can
* safely assume it will not change out from under us.
*/
fpp = fdp->fd_ofiles;
for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
if (*fpp)
(void) closef(*fpp, p);
}
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_TEMP);
if (fdp->fd_knhash)
FREE(fdp->fd_knhash, M_TEMP);
FREE(fdp, M_FILEDESC);
}
/*
* For setugid programs, we don't want to people to use that setugidness
* to generate error messages which write to a file which otherwise would
* otherwise be off-limits to the process.
*
* This is a gross hack to plug the hole. A better solution would involve
* a special vop or other form of generalized access control mechanism. We
* go ahead and just reject all procfs file systems accesses as dangerous.
*
* Since setugidsafety calls this only for fd 0, 1 and 2, this check is
* sufficient. We also don't for check setugidness since we know we are.
*/
static int
is_unsafe(struct file *fp)
{
if (fp->f_type == DTYPE_VNODE &&
((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS)
return (1);
return (0);
}
/*
* Make this setguid thing safe, if at all possible.
*/
void
setugidsafety(p)
struct proc *p;
{
struct filedesc *fdp = p->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!
*/
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(p, i);
#endif
if (i < fdp->fd_knlistsize)
knote_fdclose(p, i);
/*
* 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;
(void) closef(fp, p);
}
}
while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
fdp->fd_lastfile--;
}
/*
* Close any files on exec?
*/
void
fdcloseexec(p)
struct proc *p;
{
struct filedesc *fdp = p->p_fd;
register int i;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return;
/*
* 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(p, i);
#endif
if (i < fdp->fd_knlistsize)
knote_fdclose(p, i);
/*
* 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;
(void) closef(fp, p);
}
}
while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
fdp->fd_lastfile--;
}
/*
* Internal form of close.
* Decrement reference count on file structure.
* Note: p may be NULL when closing a file
* that was being passed in a message.
*/
int
closef(fp, p)
register struct file *fp;
register struct proc *p;
{
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 (p && (p->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)p->p_leader, F_UNLCK, &lf, F_POSIX);
}
return (fdrop(fp, p));
}
int
fdrop(fp, p)
struct file *fp;
struct proc *p;
{
struct flock lf;
struct vnode *vp;
int error;
if (--fp->f_count > 0)
return (0);
if (fp->f_count < 0)
panic("fdrop: count < 0");
if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = (struct vnode *)fp->f_data;
(void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
}
if (fp->f_ops != &badfileops)
error = fo_close(fp, p);
else
error = 0;
ffree(fp);
return (error);
}
/*
* Apply an advisory lock on a file descriptor.
*
* Just attempt to get a record lock of the requested type on
* the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
*/
#ifndef _SYS_SYSPROTO_H_
struct flock_args {
int fd;
int how;
};
#endif
/* ARGSUSED */
int
flock(p, uap)
struct proc *p;
register struct flock_args *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
struct vnode *vp;
struct flock lf;
if ((unsigned)uap->fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL)
return (EBADF);
if (fp->f_type != DTYPE_VNODE)
return (EOPNOTSUPP);
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;
fp->f_flag &= ~FHASLOCK;
return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK));
}
if (uap->how & LOCK_EX)
lf.l_type = F_WRLCK;
else if (uap->how & LOCK_SH)
lf.l_type = F_RDLCK;
else
return (EBADF);
fp->f_flag |= FHASLOCK;
if (uap->how & LOCK_NB)
return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK));
return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT));
}
/*
* 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, p)
dev_t dev;
int mode, type;
struct proc *p;
{
/*
* XXX Kludge: set curproc->p_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.
*/
p->p_dupfd = dev2unit(dev);
return (ENODEV);
}
/*
* Duplicate the specified descriptor to a free descriptor.
*/
int
dupfdopen(p, fdp, indx, dfd, mode, error)
struct proc *p;
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.
*/
if ((u_int)dfd >= fdp->fd_nfiles ||
(wfp = fdp->fd_ofiles[dfd]) == NULL) {
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.
*/
if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag)
return (EACCES);
fp = fdp->fd_ofiles[indx];
#if 0
if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED)
(void) munmapfd(p, indx);
#endif
fdp->fd_ofiles[indx] = wfp;
fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
fhold(wfp);
if (indx > fdp->fd_lastfile)
fdp->fd_lastfile = indx;
/*
* we now own the reference to fp that the ofiles[] array
* used to own. Release it.
*/
if (fp)
fdrop(fp, p);
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(p, 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;
/*
* we now own the reference to fp that the ofiles[] array
* used to own. Release it.
*/
if (fp)
fdrop(fp, p);
/*
* 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;
}
return (0);
default:
return (error);
}
/* NOTREACHED */
}
/*
* Get file structures.
*/
static int
sysctl_kern_file(SYSCTL_HANDLER_ARGS)
{
int error;
struct file *fp;
if (!req->oldptr) {
/*
* overestimate by 10 files
*/
return (SYSCTL_OUT(req, 0, sizeof(filehead) +
(nfiles + 10) * sizeof(struct file)));
}
error = SYSCTL_OUT(req, (caddr_t)&filehead, sizeof(filehead));
if (error)
return (error);
/*
* followed by an array of file structures
*/
LIST_FOREACH(fp, &filehead, f_list) {
error = SYSCTL_OUT(req, (caddr_t)fp, sizeof (struct file));
if (error)
return (error);
}
return (0);
}
SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
0, 0, sysctl_kern_file, "S,file", "Entire file table");
SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
&maxfilesperproc, 0, "Maximum files allowed open per process");
SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
&maxfiles, 0, "Maximum number of files");
SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
&nfiles, 0, "System-wide number of open files");
static void
fildesc_clone(void *arg, char *name, int namelen, dev_t *dev)
{
int u;
if (*dev != NODEV)
return;
if (dev_stdclone(name, NULL, "fd/", &u) != 1)
return;
if (u <= 2)
return;
/* Don't clone higher than it makes sense */
if (u >= maxfilesperproc)
return;
/* And don't clone higher than our minors will support */
if (u > 0xffffff)
return;
u = unit2minor(u);
*dev = make_dev(&fildesc_cdevsw, u, UID_BIN, GID_BIN, 0666, name);
return;
}
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");
EVENTHANDLER_REGISTER(dev_clone, fildesc_clone, 0, 1000);
if (!devfs_present) {
int fd;
for (fd = 3; fd < NUMFDESC; fd++)
make_dev(&fildesc_cdevsw, fd, UID_BIN, GID_BIN, 0666,
"fd/%d", fd);
}
}
struct fileops badfileops = {
badfo_readwrite,
badfo_readwrite,
badfo_ioctl,
badfo_poll,
badfo_kqfilter,
badfo_stat,
badfo_close
};
static int
badfo_readwrite(fp, uio, cred, flags, p)
struct file *fp;
struct uio *uio;
struct ucred *cred;
struct proc *p;
int flags;
{
return (EBADF);
}
static int
badfo_ioctl(fp, com, data, p)
struct file *fp;
u_long com;
caddr_t data;
struct proc *p;
{
return (EBADF);
}
static int
badfo_poll(fp, events, cred, p)
struct file *fp;
int events;
struct ucred *cred;
struct proc *p;
{
return (0);
}
static int
badfo_kqfilter(fp, kn)
struct file *fp;
struct knote *kn;
{
return (0);
}
static int
badfo_stat(fp, sb, p)
struct file *fp;
struct stat *sb;
struct proc *p;
{
return (EBADF);
}
static int
badfo_close(fp, p)
struct file *fp;
struct proc *p;
{
return (EBADF);
}
SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,
fildesc_drvinit,NULL)
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