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freebsd-skq/sys/kern/kern_descrip.c

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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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/limits.h>
#include <sys/systm.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/conf.h>
#include <sys/filedesc.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/mount.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 <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_FILEDESC_TO_LEADER, "file desc to leader",
"file desc to leader structures");
static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
static uma_zone_t file_zone;
static d_open_t fdopen;
#define NUMFDESC 64
#define CDEV_MAJOR 22
static struct cdevsw fildesc_cdevsw = {
.d_open = fdopen,
.d_name = "FD",
.d_maj = CDEV_MAJOR,
};
/* 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 fd_first_free(struct filedesc *, int, int);
static int fd_last_used(struct filedesc *, int, int);
static void fdgrowtable(struct filedesc *, int);
/*
* Descriptor management.
*/
struct filelist filehead; /* head of list of open files */
int nfiles; /* actual number of open files */
struct sx filelist_lock; /* sx to protect filelist */
struct mtx sigio_lock; /* mtx to protect pointers to sigio */
/*
* Find the first zero bit in the given bitmap, starting at low and not
* exceeding size - 1.
*/
static int
fd_first_free(struct filedesc *fdp, int low, int size)
{
NDSLOTTYPE *map = fdp->fd_map;
NDSLOTTYPE mask;
int off, maxoff;
if (low >= size)
return (low);
off = NDSLOT(low);
if (low % NDENTRIES) {
mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES)));
if ((mask &= ~map[off]) != 0)
return (off * NDENTRIES + ffsl(mask) - 1);
++off;
}
for (maxoff = NDSLOTS(size); off < maxoff; ++off)
if ((mask = ~map[off]) != 0)
return (off * NDENTRIES + ffsl(mask) - 1);
return (size);
}
/*
* Find the highest non-zero bit in the given bitmap, starting at low and
* not exceeding size - 1.
*/
static int
fd_last_used(struct filedesc *fdp, int low, int size)
{
NDSLOTTYPE *map = fdp->fd_map;
NDSLOTTYPE mask;
int off, minoff;
if (low >= size)
return (-1);
off = NDSLOT(size);
if (size % NDENTRIES) {
mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES));
if ((mask &= map[off]) != 0)
return (off * NDENTRIES + flsl(mask) - 1);
--off;
}
for (minoff = NDSLOT(low); off >= minoff; --off)
if ((mask = map[off]) != 0)
return (off * NDENTRIES + flsl(mask) - 1);
return (size - 1);
}
static int
fdisused(struct filedesc *fdp, int fd)
{
KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0);
}
/*
* Mark a file descriptor as used.
*/
void
fdused(struct filedesc *fdp, int fd)
{
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
KASSERT(!fdisused(fdp, fd),
("fd already used"));
fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
if (fd > fdp->fd_lastfile)
fdp->fd_lastfile = fd;
if (fd == fdp->fd_freefile)
fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles);
}
/*
* Mark a file descriptor as unused.
*/
void
fdunused(struct filedesc *fdp, int fd)
{
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
KASSERT(fdisused(fdp, fd),
("fd is already unused"));
KASSERT(fdp->fd_ofiles[fd] == NULL,
("fd is still in use"));
fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd);
if (fd < fdp->fd_freefile)
fdp->fd_freefile = fd;
if (fd == fdp->fd_lastfile)
fdp->fd_lastfile = fd_last_used(fdp, 0, fd);
}
/*
* 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;
struct fcntl_args *uap;
{
struct flock fl;
intptr_t arg;
int error;
error = 0;
switch (uap->cmd) {
case F_GETLK:
case F_SETLK:
case F_SETLKW:
error = copyin((void *)(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);
if (uap->cmd == F_GETLK)
error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl));
return (error);
}
int
kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
{
struct filedesc *fdp;
struct flock *flp;
struct file *fp;
struct proc *p;
char *pop;
struct vnode *vp;
u_int newmin;
int error, flg, tmp;
error = 0;
flg = F_POSIX;
p = td->td_proc;
fdp = p->p_fd;
mtx_lock(&Giant);
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:
FILE_LOCK(fp);
FILEDESC_UNLOCK(fdp);
fhold_locked(fp);
fp->f_flag &= ~FCNTLFLAGS;
fp->f_flag |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS;
FILE_UNLOCK(fp);
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 == 0) {
fdrop(fp, td);
break;
}
FILE_LOCK(fp);
fp->f_flag &= ~FNONBLOCK;
FILE_UNLOCK(fp);
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, &tmp, td->td_ucred, td);
if (error == 0)
td->td_retval[0] = tmp;
fdrop(fp, td);
break;
case F_SETOWN:
fhold(fp);
FILEDESC_UNLOCK(fdp);
tmp = arg;
error = fo_ioctl(fp, FIOSETOWN, &tmp, 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;
}
/*
* VOP_ADVLOCK() may block.
*/
fhold(fp);
FILEDESC_UNLOCK(fdp);
vp = fp->f_vnode;
switch (flp->l_type) {
case F_RDLCK:
if ((fp->f_flag & FREAD) == 0) {
error = EBADF;
break;
}
PROC_LOCK(p->p_leader);
p->p_leader->p_flag |= P_ADVLOCK;
PROC_UNLOCK(p->p_leader);
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
flp, flg);
break;
case F_WRLCK:
if ((fp->f_flag & FWRITE) == 0) {
error = EBADF;
break;
}
PROC_LOCK(p->p_leader);
p->p_leader->p_flag |= P_ADVLOCK;
PROC_UNLOCK(p->p_leader);
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
flp, flg);
break;
case F_UNLCK:
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
flp, F_POSIX);
break;
default:
error = EINVAL;
break;
}
/* Check for race with close */
FILEDESC_LOCK(fdp);
if ((unsigned) fd >= fdp->fd_nfiles ||
fp != fdp->fd_ofiles[fd]) {
FILEDESC_UNLOCK(fdp);
flp->l_whence = SEEK_SET;
flp->l_start = 0;
flp->l_len = 0;
flp->l_type = F_UNLCK;
(void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
F_UNLCK, flp, F_POSIX);
} else
FILEDESC_UNLOCK(fdp);
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;
}
/*
* VOP_ADVLOCK() may block.
*/
fhold(fp);
FILEDESC_UNLOCK(fdp);
vp = fp->f_vnode;
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).
*/
static int
do_dup(td, type, old, new, retval)
enum dup_type type;
int old, new;
register_t *retval;
struct thread *td;
{
struct filedesc *fdp;
struct proc *p;
struct file *fp;
struct file *delfp;
int error, holdleaders, maxfd;
KASSERT((type == DUP_VARIABLE || type == DUP_FIXED),
("invalid dup type %d", type));
p = td->td_proc;
fdp = p->p_fd;
/*
* Verify we have a valid descriptor to dup from and possibly to
* dup to.
*/
if (old < 0 || new < 0)
return (EBADF);
maxfd = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
if (new >= maxfd)
return (EMFILE);
FILEDESC_LOCK(fdp);
if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) {
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);
/*
* If the caller specified a file descriptor, make sure the file
* table is large enough to hold it, and grab it. Otherwise, just
* allocate a new descriptor the usual way. Since the filedesc
* lock may be temporarily dropped in the process, we have to look
* out for a race.
*/
if (type == DUP_FIXED) {
if (new >= fdp->fd_nfiles)
fdgrowtable(fdp, new + 1);
if (fdp->fd_ofiles[new] == NULL)
fdused(fdp, new);
} else {
if ((error = fdalloc(td, &new)) != 0) {
FILEDESC_UNLOCK(fdp);
fdrop(fp, td);
return (error);
}
}
/*
* 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) {
/* we've allocated a descriptor which we won't use */
if (fdp->fd_ofiles[new] == NULL)
fdunused(fdp, new);
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 cannot close
* it without introducing an ownership race for the slot, since we
* need to drop the filedesc lock to call closef().
*
* XXX this duplicates parts of close().
*/
delfp = fdp->fd_ofiles[new];
holdleaders = 0;
if (delfp != NULL) {
if (td->td_proc->p_fdtol != NULL) {
/*
* Ask fdfree() to sleep to ensure that all relevant
* process leaders can be traversed in closef().
*/
fdp->fd_holdleaderscount++;
holdleaders = 1;
}
}
/*
* Duplicate the source descriptor
*/
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).
*
* XXX this duplicates parts of close().
*/
if (delfp != NULL) {
/* XXX need to call knote_fdclose() */
mtx_lock(&Giant);
(void) closef(delfp, td);
mtx_unlock(&Giant);
if (holdleaders) {
FILEDESC_LOCK(fdp);
fdp->fd_holdleaderscount--;
if (fdp->fd_holdleaderscount == 0 &&
fdp->fd_holdleaderswakeup != 0) {
fdp->fd_holdleaderswakeup = 0;
wakeup(&fdp->fd_holdleaderscount);
}
FILEDESC_UNLOCK(fdp);
}
}
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 proc *p;
struct pgrp *pg;
struct sigio *sigio;
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(sigiop)
struct sigio **sigiop;
{
pid_t pgid;
SIGIO_LOCK();
pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0;
SIGIO_UNLOCK();
return (pgid);
}
/*
* 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;
{
struct filedesc *fdp;
struct file *fp;
int fd, error;
int holdleaders;
fd = uap->fd;
error = 0;
holdleaders = 0;
fdp = td->td_proc->p_fd;
mtx_lock(&Giant);
FILEDESC_LOCK(fdp);
if ((unsigned)fd >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[fd]) == NULL) {
FILEDESC_UNLOCK(fdp);
mtx_unlock(&Giant);
return (EBADF);
}
fdp->fd_ofiles[fd] = NULL;
fdp->fd_ofileflags[fd] = 0;
fdunused(fdp, fd);
if (td->td_proc->p_fdtol != NULL) {
/*
* Ask fdfree() to sleep to ensure that all relevant
* process leaders can be traversed in closef().
*/
fdp->fd_holdleaderscount++;
holdleaders = 1;
}
/*
* we now hold the fp reference that used to be owned by the descriptor
* array.
*/
if (fd < fdp->fd_knlistsize) {
FILEDESC_UNLOCK(fdp);
knote_fdclose(td, fd);
} else
FILEDESC_UNLOCK(fdp);
error = closef(fp, td);
mtx_unlock(&Giant);
if (holdleaders) {
FILEDESC_LOCK(fdp);
fdp->fd_holdleaderscount--;
if (fdp->fd_holdleaderscount == 0 &&
fdp->fd_holdleaderswakeup != 0) {
fdp->fd_holdleaderswakeup = 0;
wakeup(&fdp->fd_holdleaderscount);
}
FILEDESC_UNLOCK(fdp);
}
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;
struct ofstat_args *uap;
{
struct file *fp;
struct stat ub;
struct ostat oub;
int error;
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
mtx_lock(&Giant);
error = fo_stat(fp, &ub, td->td_ucred, td);
mtx_unlock(&Giant);
if (error == 0) {
cvtstat(&ub, &oub);
error = copyout(&oub, uap->sb, sizeof(oub));
}
fdrop(fp, td);
done2:
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;
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
mtx_lock(&Giant);
error = fo_stat(fp, &ub, td->td_ucred, td);
mtx_unlock(&Giant);
if (error == 0)
error = copyout(&ub, uap->sb, sizeof(ub));
fdrop(fp, td);
done2:
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;
struct nfstat_args *uap;
{
struct file *fp;
struct stat ub;
struct nstat nub;
int error;
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
mtx_lock(&Giant);
error = fo_stat(fp, &ub, td->td_ucred, td);
mtx_unlock(&Giant);
if (error == 0) {
cvtnstat(&ub, &nub);
error = copyout(&nub, uap->sb, sizeof(nub));
}
fdrop(fp, td);
done2:
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;
struct fpathconf_args *uap;
{
struct file *fp;
struct vnode *vp;
int error;
if ((error = fget(td, uap->fd, &fp)) != 0)
return (error);
/* If asynchronous I/O is available, it works for all descriptors. */
if (uap->name == _PC_ASYNC_IO) {
td->td_retval[0] = async_io_version;
goto out;
}
vp = fp->f_vnode;
if (vp != NULL) {
mtx_lock(&Giant);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
error = VOP_PATHCONF(vp, uap->name, td->td_retval);
VOP_UNLOCK(vp, 0, td);
mtx_unlock(&Giant);
} else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) {
if (uap->name != _PC_PIPE_BUF) {
error = EINVAL;
} else {
td->td_retval[0] = PIPE_BUF;
error = 0;
}
} else {
error = EOPNOTSUPP;
}
out:
fdrop(fp, td);
return (error);
}
/*
* Grow the file table to accomodate (at least) nfd descriptors. This may
* block and drop the filedesc lock, but it will reacquire it before
* returing.
*/
static void
fdgrowtable(struct filedesc *fdp, int nfd)
{
struct file **ntable;
char *nfileflags;
int nnfiles, onfiles;
NDSLOTTYPE *nmap;
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
KASSERT(fdp->fd_nfiles > 0,
("zero-length file table"));
/* compute the size of the new table */
onfiles = fdp->fd_nfiles;
nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */
if (nnfiles <= onfiles)
/* the table is already large enough */
return;
/* allocate a new table and (if required) new bitmaps */
FILEDESC_UNLOCK(fdp);
MALLOC(ntable, struct file **, nnfiles * OFILESIZE,
M_FILEDESC, M_ZERO | M_WAITOK);
nfileflags = (char *)&ntable[nnfiles];
if (NDSLOTS(nnfiles) > NDSLOTS(onfiles))
MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE,
M_FILEDESC, M_ZERO | M_WAITOK);
else
nmap = NULL;
FILEDESC_LOCK(fdp);
/*
* We now have new tables ready to go. Since we dropped the
* filedesc lock to call malloc(), watch out for a race.
*/
onfiles = fdp->fd_nfiles;
if (onfiles >= nnfiles) {
/* we lost the race, but that's OK */
free(ntable, M_FILEDESC);
if (nmap != NULL)
free(nmap, M_FILEDESC);
return;
}
bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable));
bcopy(fdp->fd_ofileflags, nfileflags, onfiles);
if (onfiles > NDFILE)
free(fdp->fd_ofiles, M_FILEDESC);
fdp->fd_ofiles = ntable;
fdp->fd_ofileflags = nfileflags;
if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) {
bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap));
if (NDSLOTS(onfiles) > NDSLOTS(NDFILE))
free(fdp->fd_map, M_FILEDESC);
fdp->fd_map = nmap;
}
fdp->fd_nfiles = nnfiles;
}
/*
* Allocate a file descriptor for the process.
*/
int
fdalloc(struct thread *td, int *result)
{
struct proc *p = td->td_proc;
struct filedesc *fdp = p->p_fd;
int fd = -1, maxfd;
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
maxfd = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
/*
* Search the bitmap for a free descriptor. If none is found, try
* to grow the file table. Keep at it until we either get a file
* descriptor or run into process or system limits; fdgrowtable()
* may drop the filedesc lock, so we're in a race.
*/
for (;;) {
fd = fd_first_free(fdp, fdp->fd_freefile, fdp->fd_nfiles);
if (fd >= maxfd)
return (EMFILE);
if (fd < fdp->fd_nfiles)
break;
fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd));
}
/*
* Perform some sanity checks, then mark the file descriptor as
* used and return it to the caller.
*/
KASSERT(!fdisused(fdp, fd),
("fd_first_free() returned non-free descriptor"));
KASSERT(fdp->fd_ofiles[fd] == NULL,
("free descriptor isn't"));
fdp->fd_ofileflags[fd] = 0; /* XXX needed? */
fdused(fdp, fd);
fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles);
*result = fd;
return (0);
}
/*
* Check to see whether n user file descriptors
* are available to the process p.
*/
int
fdavail(td, n)
struct thread *td;
int n;
{
struct proc *p = td->td_proc;
struct filedesc *fdp = td->td_proc->p_fd;
struct file **fpp;
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.
* We add one reference to the file for the descriptor table
* and one reference for resultfp. This is to prevent us being
* prempted and the entry in the descriptor table closed after
* we release the FILEDESC lock.
*/
int
falloc(td, resultfp, resultfd)
struct thread *td;
struct file **resultfp;
int *resultfd;
{
struct proc *p = td->td_proc;
struct file *fp, *fq;
int error, i;
int maxuserfiles = maxfiles - (maxfiles / 20);
static struct timeval lastfail;
static int curfail;
fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO);
sx_xlock(&filelist_lock);
if ((nfiles >= maxuserfiles && td->td_ucred->cr_ruid != 0)
|| nfiles >= maxfiles) {
if (ppsratecheck(&lastfail, &curfail, 1)) {
printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n",
td->td_ucred->cr_ruid);
}
sx_xunlock(&filelist_lock);
uma_zfree(file_zone, fp);
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(mtxpool_sleep);
fp->f_count = 1;
if (resultfp)
fp->f_count++;
fp->f_cred = crhold(td->td_ucred);
fp->f_ops = &badfileops;
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, &i))) {
FILEDESC_UNLOCK(p->p_fd);
fdrop(fp, td);
if (resultfp)
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)
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 from another.
* Copy the current, root, and jail root vnode references.
*/
struct filedesc *
fdinit(fdp)
struct filedesc *fdp;
{
struct filedesc0 *newfdp;
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
FILEDESC_UNLOCK(fdp);
MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0),
M_FILEDESC, M_WAITOK | M_ZERO);
FILEDESC_LOCK(fdp);
mtx_init(&newfdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF);
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;
newfdp->fd_fd.fd_map = newfdp->fd_dmap;
return (&newfdp->fd_fd);
}
/*
* Share a filedesc structure.
*/
struct filedesc *
fdshare(fdp)
struct filedesc *fdp;
{
FILEDESC_LOCK(fdp);
fdp->fd_refcnt++;
FILEDESC_UNLOCK(fdp);
return (fdp);
}
/*
* Copy a filedesc structure.
* A NULL pointer in returns a NULL reference, this is to ease callers,
* not catch errors.
*/
struct filedesc *
fdcopy(fdp)
struct filedesc *fdp;
{
struct filedesc *newfdp;
int i;
/* Certain daemons might not have file descriptors. */
if (fdp == NULL)
return (NULL);
FILEDESC_LOCK_ASSERT(fdp, MA_OWNED);
newfdp = fdinit(fdp);
FILEDESC_LOCK(newfdp);
while (fdp->fd_lastfile >= newfdp->fd_nfiles) {
FILEDESC_UNLOCK(fdp);
fdgrowtable(newfdp, fdp->fd_lastfile + 1);
FILEDESC_LOCK(fdp);
}
/* copy everything except kqueue descriptors */
newfdp->fd_freefile = -1;
for (i = 0; i <= fdp->fd_lastfile; ++i) {
if (fdisused(fdp, i) &&
fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) {
newfdp->fd_ofiles[i] = fdp->fd_ofiles[i];
newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i];
fdused(newfdp, i);
fhold(newfdp->fd_ofiles[i]);
newfdp->fd_lastfile = i;
} else {
if (newfdp->fd_freefile == -1)
newfdp->fd_freefile = i;
}
}
if (newfdp->fd_freefile == -1)
newfdp->fd_freefile = i;
newfdp->fd_cmask = fdp->fd_cmask;
FILEDESC_UNLOCK(newfdp);
return (newfdp);
}
/* A mutex to protect the association between a proc and filedesc. */
struct mtx fdesc_mtx;
MTX_SYSINIT(fdesc, &fdesc_mtx, "fdesc", MTX_DEF);
/*
* Release a filedesc structure.
*/
void
fdfree(td)
struct thread *td;
{
struct filedesc *fdp;
struct file **fpp;
int i;
struct filedesc_to_leader *fdtol;
struct file *fp;
struct vnode *vp;
struct flock lf;
/* Certain daemons might not have file descriptors. */
fdp = td->td_proc->p_fd;
if (fdp == NULL)
return;
/* Check for special need to clear POSIX style locks */
fdtol = td->td_proc->p_fdtol;
if (fdtol != NULL) {
FILEDESC_LOCK(fdp);
KASSERT(fdtol->fdl_refcount > 0,
("filedesc_to_refcount botch: fdl_refcount=%d",
fdtol->fdl_refcount));
if (fdtol->fdl_refcount == 1 &&
(td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
i = 0;
fpp = fdp->fd_ofiles;
for (i = 0, fpp = fdp->fd_ofiles;
i <= fdp->fd_lastfile;
i++, fpp++) {
if (*fpp == NULL ||
(*fpp)->f_type != DTYPE_VNODE)
continue;
fp = *fpp;
fhold(fp);
FILEDESC_UNLOCK(fdp);
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = fp->f_vnode;
(void) VOP_ADVLOCK(vp,
(caddr_t)td->td_proc->
p_leader,
F_UNLCK,
&lf,
F_POSIX);
FILEDESC_LOCK(fdp);
fdrop(fp, td);
fpp = fdp->fd_ofiles + i;
}
}
retry:
if (fdtol->fdl_refcount == 1) {
if (fdp->fd_holdleaderscount > 0 &&
(td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
/*
* close() or do_dup() has cleared a reference
* in a shared file descriptor table.
*/
fdp->fd_holdleaderswakeup = 1;
msleep(&fdp->fd_holdleaderscount, &fdp->fd_mtx,
PLOCK, "fdlhold", 0);
goto retry;
}
if (fdtol->fdl_holdcount > 0) {
/*
* Ensure that fdtol->fdl_leader
* remains valid in closef().
*/
fdtol->fdl_wakeup = 1;
msleep(fdtol, &fdp->fd_mtx,
PLOCK, "fdlhold", 0);
goto retry;
}
}
fdtol->fdl_refcount--;
if (fdtol->fdl_refcount == 0 &&
fdtol->fdl_holdcount == 0) {
fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
} else
fdtol = NULL;
td->td_proc->p_fdtol = NULL;
FILEDESC_UNLOCK(fdp);
if (fdtol != NULL)
FREE(fdtol, M_FILEDESC_TO_LEADER);
}
FILEDESC_LOCK(fdp);
if (--fdp->fd_refcnt > 0) {
FILEDESC_UNLOCK(fdp);
return;
}
/*
* We are the last reference to the structure, so 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);
}
/* XXX This should happen earlier. */
mtx_lock(&fdesc_mtx);
td->td_proc->p_fd = NULL;
mtx_unlock(&fdesc_mtx);
if (fdp->fd_nfiles > NDFILE)
FREE(fdp->fd_ofiles, M_FILEDESC);
if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE))
FREE(fdp->fd_map, 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. We check for filesystems where
* the vnode can change out from under us after execve (like [lin]procfs).
*
* 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 *vp = fp->f_vnode;
if ((vp->v_vflag & VV_PROCDEP) != 0)
return (1);
}
return (0);
}
/*
* Make this setguid thing safe, if at all possible.
*/
void
setugidsafety(td)
struct thread *td;
{
struct filedesc *fdp;
int i;
/* Certain daemons might not have file descriptors. */
fdp = td->td_proc->p_fd;
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 (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;
fdunused(fdp, i);
FILEDESC_UNLOCK(fdp);
(void) closef(fp, td);
FILEDESC_LOCK(fdp);
}
}
FILEDESC_UNLOCK(fdp);
}
/*
* Close any files on exec?
*/
void
fdcloseexec(td)
struct thread *td;
{
struct filedesc *fdp;
int i;
/* Certain daemons might not have file descriptors. */
fdp = td->td_proc->p_fd;
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 (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;
fdunused(fdp, i);
FILEDESC_UNLOCK(fdp);
(void) closef(fp, td);
FILEDESC_LOCK(fdp);
}
}
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, extraref;
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;
/* Note extra ref on `fp' held for us by falloc(). */
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, -1);
if (error != 0) {
/*
* Someone may have closed the entry in the
* file descriptor table, so check it hasn't
* changed before dropping the reference count.
*/
extraref = 0;
FILEDESC_LOCK(fdp);
if (fdp->fd_ofiles[fd] == fp) {
fdp->fd_ofiles[fd] = NULL;
fdunused(fdp, fd);
extraref = 1;
}
FILEDESC_UNLOCK(fdp);
fdrop(fp, td);
if (extraref)
fdrop(fp, td);
break;
}
NDFREE(&nd, NDF_ONLY_PNBUF);
fp->f_vnode = nd.ni_vp;
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;
fdrop(fp, td);
} 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)
struct file *fp;
struct thread *td;
{
struct vnode *vp;
struct flock lf;
struct filedesc_to_leader *fdtol;
struct filedesc *fdp;
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 != NULL &&
fp->f_type == DTYPE_VNODE) {
if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = fp->f_vnode;
(void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader,
F_UNLCK, &lf, F_POSIX);
}
fdtol = td->td_proc->p_fdtol;
if (fdtol != NULL) {
/*
* Handle special case where file descriptor table
* is shared between multiple process leaders.
*/
fdp = td->td_proc->p_fd;
FILEDESC_LOCK(fdp);
for (fdtol = fdtol->fdl_next;
fdtol != td->td_proc->p_fdtol;
fdtol = fdtol->fdl_next) {
if ((fdtol->fdl_leader->p_flag &
P_ADVLOCK) == 0)
continue;
fdtol->fdl_holdcount++;
FILEDESC_UNLOCK(fdp);
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = fp->f_vnode;
(void) VOP_ADVLOCK(vp,
(caddr_t)fdtol->fdl_leader,
F_UNLCK, &lf, F_POSIX);
FILEDESC_LOCK(fdp);
fdtol->fdl_holdcount--;
if (fdtol->fdl_holdcount == 0 &&
fdtol->fdl_wakeup != 0) {
fdtol->fdl_wakeup = 0;
wakeup(fdtol);
}
}
FILEDESC_UNLOCK(fdp);
}
}
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_vnode == NULL) {
error = EINVAL;
} else {
*vpp = fp->f_vnode;
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 != NULL)
*fflagp = 0;
if ((error = _fget(td, fd, &fp, 0, 0)) != 0)
return (error);
if (fp->f_type != DTYPE_SOCKET) {
error = ENOTSOCK;
} else {
*spp = 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);
}
/* We have the last ref so we can proceed without the file lock. */
FILE_UNLOCK(fp);
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 = fp->f_vnode;
(void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
}
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;
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 = fp->f_vnode;
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;
{
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 (dfd < 0 || 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];
fdp->fd_ofiles[indx] = wfp;
fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
if (fp == NULL)
fdused(fdp, indx);
fhold_locked(wfp);
FILE_UNLOCK(wfp);
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];
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;
fdunused(fdp, dfd);
if (fp == NULL)
fdused(fdp, 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);
default:
FILEDESC_UNLOCK(fdp);
return (error);
}
/* NOTREACHED */
}
struct filedesc_to_leader *
filedesc_to_leader_alloc(struct filedesc_to_leader *old,
struct filedesc *fdp,
struct proc *leader)
{
struct filedesc_to_leader *fdtol;
MALLOC(fdtol, struct filedesc_to_leader *,
sizeof(struct filedesc_to_leader),
M_FILEDESC_TO_LEADER,
M_WAITOK);
fdtol->fdl_refcount = 1;
fdtol->fdl_holdcount = 0;
fdtol->fdl_wakeup = 0;
fdtol->fdl_leader = leader;
if (old != NULL) {
FILEDESC_LOCK(fdp);
fdtol->fdl_next = old->fdl_next;
fdtol->fdl_prev = old;
old->fdl_next = fdtol;
fdtol->fdl_next->fdl_prev = fdtol;
FILEDESC_UNLOCK(fdp);
} else {
fdtol->fdl_next = fdtol;
fdtol->fdl_prev = fdtol;
}
return (fdtol);
}
/*
* Get file structures.
*/
static int
sysctl_kern_file(SYSCTL_HANDLER_ARGS)
{
struct xfile xf;
struct filedesc *fdp;
struct file *fp;
struct proc *p;
int error, n;
/*
* Note: because the number of file descriptors is calculated
* in different ways for sizing vs returning the data,
* there is information leakage from the first loop. However,
* it is of a similar order of magnitude to the leakage from
* global system statistics such as kern.openfiles.
*/
sysctl_wire_old_buffer(req, 0);
if (req->oldptr == NULL) {
n = 16; /* A 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);
if (p_cansee(req->td, p) != 0) {
PROC_UNLOCK(p);
continue;
}
xf.xf_pid = p->p_pid;
xf.xf_uid = p->p_ucred->cr_uid;
PROC_UNLOCK(p);
mtx_lock(&fdesc_mtx);
if ((fdp = p->p_fd) == NULL) {
mtx_unlock(&fdesc_mtx);
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;
xf.xf_data = fp->f_data;
xf.xf_type = fp->f_type;
xf.xf_count = fp->f_count;
xf.xf_msgcount = fp->f_msgcount;
xf.xf_offset = fp->f_offset;
xf.xf_flag = fp->f_flag;
error = SYSCTL_OUT(req, &xf, sizeof(xf));
if (error)
break;
}
FILEDESC_UNLOCK(fdp);
mtx_unlock(&fdesc_mtx);
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_ROOT, GID_WHEEL, 0666, "fd/0");
make_dev_alias(dev, "stdin");
dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1");
make_dev_alias(dev, "stdout");
dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2");
make_dev_alias(dev, "stderr");
}
static fo_rdwr_t badfo_readwrite;
static fo_ioctl_t badfo_ioctl;
static fo_poll_t badfo_poll;
static fo_kqfilter_t badfo_kqfilter;
static fo_stat_t badfo_stat;
static fo_close_t badfo_close;
struct fileops badfileops = {
.fo_read = badfo_readwrite,
.fo_write = badfo_readwrite,
.fo_ioctl = badfo_ioctl,
.fo_poll = badfo_poll,
.fo_kqfilter = badfo_kqfilter,
.fo_stat = badfo_stat,
.fo_close = 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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