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freebsd-dev/sys/kern/kern_descrip.c
Mark Johnston f52979098d Fix a pair of races in SIGIO registration 
First, funsetownlst() list looks at the first element of the list to see
whether it's processing a process or a process group list.  Then it
acquires the global sigio lock and processes the list.  However, nothing
prevents the first sigio tracker from being freed by a concurrent
funsetown() before the sigio lock is acquired.

Fix this by acquiring the global sigio lock immediately after checking
whether the list is empty.  Callers of funsetownlst() ensure that new
sigio trackers cannot be added concurrently.

Second, fsetown() uses funsetown() to remove an existing sigio structure
from a file object.  However, funsetown() uses a racy check to avoid the
sigio lock, so two threads may call fsetown() on the same file object,
both observe that no sigio tracker is present, and enqueue two sigio
trackers for the same file object.  However, if the file object is
destroyed, funsetown() will only remove one sigio tracker, and
funsetownlst() may later trigger a use-after-free when it clears the
file object reference for each entry in the list.

Fix this by introducing funsetown_locked(), which avoids the racy check.

Reviewed by:	kib
Reported by:	pho
Tested by:	pho
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D27157
2020-11-11 13:44:27 +00:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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. 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_capsicum.h"
#include "opt_ddb.h"
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/selinfo.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/sbuf.h>
#include <sys/signalvar.h>
#include <sys/kdb.h>
#include <sys/smr.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/unistd.h>
#include <sys/user.h>
#include <sys/vnode.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <net/vnet.h>
#include <security/audit/audit.h>
#include <vm/uma.h>
#include <vm/vm.h>
#include <ddb/ddb.h>
static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table");
static MALLOC_DEFINE(M_PWD, "pwd", "Descriptor table vnodes");
static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader",
"file desc to leader structures");
static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
MALLOC_DEFINE(M_FILECAPS, "filecaps", "descriptor capabilities");
MALLOC_DECLARE(M_FADVISE);
static __read_mostly uma_zone_t file_zone;
static __read_mostly uma_zone_t filedesc0_zone;
__read_mostly uma_zone_t pwd_zone;
VFS_SMR_DECLARE;
static int closefp(struct filedesc *fdp, int fd, struct file *fp,
struct thread *td, int holdleaders);
static int fd_first_free(struct filedesc *fdp, int low, int size);
static void fdgrowtable(struct filedesc *fdp, int nfd);
static void fdgrowtable_exp(struct filedesc *fdp, int nfd);
static void fdunused(struct filedesc *fdp, int fd);
static void fdused(struct filedesc *fdp, int fd);
static int getmaxfd(struct thread *td);
static u_long *filecaps_copy_prep(const struct filecaps *src);
static void filecaps_copy_finish(const struct filecaps *src,
struct filecaps *dst, u_long *ioctls);
static u_long *filecaps_free_prep(struct filecaps *fcaps);
static void filecaps_free_finish(u_long *ioctls);
static struct pwd *pwd_alloc(void);
/*
* Each process has:
*
* - An array of open file descriptors (fd_ofiles)
* - An array of file flags (fd_ofileflags)
* - A bitmap recording which descriptors are in use (fd_map)
*
* A process starts out with NDFILE descriptors. The value of NDFILE has
* been selected based the historical limit of 20 open files, and an
* assumption that the majority of processes, especially short-lived
* processes like shells, will never need more.
*
* If this initial allocation is exhausted, a larger descriptor table and
* map are allocated dynamically, and the pointers in the process's struct
* filedesc are updated to point to those. This is repeated every time
* the process runs out of file descriptors (provided it hasn't hit its
* resource limit).
*
* Since threads may hold references to individual descriptor table
* entries, the tables are never freed. Instead, they are placed on a
* linked list and freed only when the struct filedesc is released.
*/
#define NDFILE 20
#define NDSLOTSIZE sizeof(NDSLOTTYPE)
#define NDENTRIES (NDSLOTSIZE * __CHAR_BIT)
#define NDSLOT(x) ((x) / NDENTRIES)
#define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES))
#define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES)
/*
* SLIST entry used to keep track of ofiles which must be reclaimed when
* the process exits.
*/
struct freetable {
struct fdescenttbl *ft_table;
SLIST_ENTRY(freetable) ft_next;
};
/*
* Initial allocation: a filedesc structure + the head of SLIST used to
* keep track of old ofiles + enough space for NDFILE descriptors.
*/
struct fdescenttbl0 {
int fdt_nfiles;
struct filedescent fdt_ofiles[NDFILE];
};
struct filedesc0 {
struct filedesc fd_fd;
SLIST_HEAD(, freetable) fd_free;
struct fdescenttbl0 fd_dfiles;
NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)];
};
/*
* Descriptor management.
*/
static int __exclusive_cache_line openfiles; /* actual number of open files */
struct mtx sigio_lock; /* mtx to protect pointers to sigio */
void __read_mostly (*mq_fdclose)(struct thread *td, int fd, struct file *fp);
/*
* If low >= size, just return low. Otherwise find the first zero bit in the
* given bitmap, starting at low and not exceeding size - 1. Return size if
* not found.
*/
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]) != 0UL)
return (off * NDENTRIES + ffsl(mask) - 1);
++off;
}
for (maxoff = NDSLOTS(size); off < maxoff; ++off)
if (map[off] != ~0UL)
return (off * NDENTRIES + ffsl(~map[off]) - 1);
return (size);
}
/*
* Find the last used fd.
*
* Call this variant if fdp can't be modified by anyone else (e.g, during exec).
* Otherwise use fdlastfile.
*/
int
fdlastfile_single(struct filedesc *fdp)
{
NDSLOTTYPE *map = fdp->fd_map;
int off, minoff;
off = NDSLOT(fdp->fd_nfiles - 1);
for (minoff = NDSLOT(0); off >= minoff; --off)
if (map[off] != 0)
return (off * NDENTRIES + flsl(map[off]) - 1);
return (-1);
}
int
fdlastfile(struct filedesc *fdp)
{
FILEDESC_LOCK_ASSERT(fdp);
return (fdlastfile_single(fdp));
}
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.
*/
static void
fdused_init(struct filedesc *fdp, int fd)
{
KASSERT(!fdisused(fdp, fd), ("fd=%d is already used", fd));
fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
}
static void
fdused(struct filedesc *fdp, int fd)
{
FILEDESC_XLOCK_ASSERT(fdp);
fdused_init(fdp, fd);
if (fd == fdp->fd_freefile)
fdp->fd_freefile++;
}
/*
* Mark a file descriptor as unused.
*/
static void
fdunused(struct filedesc *fdp, int fd)
{
FILEDESC_XLOCK_ASSERT(fdp);
KASSERT(fdisused(fdp, fd), ("fd=%d is already unused", fd));
KASSERT(fdp->fd_ofiles[fd].fde_file == NULL,
("fd=%d is still in use", fd));
fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd);
if (fd < fdp->fd_freefile)
fdp->fd_freefile = fd;
}
/*
* Free a file descriptor.
*
* Avoid some work if fdp is about to be destroyed.
*/
static inline void
fdefree_last(struct filedescent *fde)
{
filecaps_free(&fde->fde_caps);
}
static inline void
fdfree(struct filedesc *fdp, int fd)
{
struct filedescent *fde;
fde = &fdp->fd_ofiles[fd];
#ifdef CAPABILITIES
seqc_write_begin(&fde->fde_seqc);
#endif
fde->fde_file = NULL;
#ifdef CAPABILITIES
seqc_write_end(&fde->fde_seqc);
#endif
fdefree_last(fde);
fdunused(fdp, fd);
}
/*
* System calls on descriptors.
*/
#ifndef _SYS_SYSPROTO_H_
struct getdtablesize_args {
int dummy;
};
#endif
/* ARGSUSED */
int
sys_getdtablesize(struct thread *td, struct getdtablesize_args *uap)
{
#ifdef RACCT
uint64_t lim;
#endif
td->td_retval[0] = getmaxfd(td);
#ifdef RACCT
PROC_LOCK(td->td_proc);
lim = racct_get_limit(td->td_proc, RACCT_NOFILE);
PROC_UNLOCK(td->td_proc);
if (lim < td->td_retval[0])
td->td_retval[0] = lim;
#endif
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
sys_dup2(struct thread *td, struct dup2_args *uap)
{
return (kern_dup(td, FDDUP_FIXED, 0, (int)uap->from, (int)uap->to));
}
/*
* Duplicate a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct dup_args {
u_int fd;
};
#endif
/* ARGSUSED */
int
sys_dup(struct thread *td, struct dup_args *uap)
{
return (kern_dup(td, FDDUP_NORMAL, 0, (int)uap->fd, 0));
}
/*
* The file control system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct fcntl_args {
int fd;
int cmd;
long arg;
};
#endif
/* ARGSUSED */
int
sys_fcntl(struct thread *td, struct fcntl_args *uap)
{
return (kern_fcntl_freebsd(td, uap->fd, uap->cmd, uap->arg));
}
int
kern_fcntl_freebsd(struct thread *td, int fd, int cmd, long arg)
{
struct flock fl;
struct __oflock ofl;
intptr_t arg1;
int error, newcmd;
error = 0;
newcmd = cmd;
switch (cmd) {
case F_OGETLK:
case F_OSETLK:
case F_OSETLKW:
/*
* Convert old flock structure to new.
*/
error = copyin((void *)(intptr_t)arg, &ofl, sizeof(ofl));
fl.l_start = ofl.l_start;
fl.l_len = ofl.l_len;
fl.l_pid = ofl.l_pid;
fl.l_type = ofl.l_type;
fl.l_whence = ofl.l_whence;
fl.l_sysid = 0;
switch (cmd) {
case F_OGETLK:
newcmd = F_GETLK;
break;
case F_OSETLK:
newcmd = F_SETLK;
break;
case F_OSETLKW:
newcmd = F_SETLKW;
break;
}
arg1 = (intptr_t)&fl;
break;
case F_GETLK:
case F_SETLK:
case F_SETLKW:
case F_SETLK_REMOTE:
error = copyin((void *)(intptr_t)arg, &fl, sizeof(fl));
arg1 = (intptr_t)&fl;
break;
default:
arg1 = arg;
break;
}
if (error)
return (error);
error = kern_fcntl(td, fd, newcmd, arg1);
if (error)
return (error);
if (cmd == F_OGETLK) {
ofl.l_start = fl.l_start;
ofl.l_len = fl.l_len;
ofl.l_pid = fl.l_pid;
ofl.l_type = fl.l_type;
ofl.l_whence = fl.l_whence;
error = copyout(&ofl, (void *)(intptr_t)arg, sizeof(ofl));
} else if (cmd == F_GETLK) {
error = copyout(&fl, (void *)(intptr_t)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, *fp2;
struct filedescent *fde;
struct proc *p;
struct vnode *vp;
struct mount *mp;
int error, flg, seals, tmp;
uint64_t bsize;
off_t foffset;
error = 0;
flg = F_POSIX;
p = td->td_proc;
fdp = p->p_fd;
AUDIT_ARG_FD(cmd);
AUDIT_ARG_CMD(cmd);
switch (cmd) {
case F_DUPFD:
tmp = arg;
error = kern_dup(td, FDDUP_FCNTL, 0, fd, tmp);
break;
case F_DUPFD_CLOEXEC:
tmp = arg;
error = kern_dup(td, FDDUP_FCNTL, FDDUP_FLAG_CLOEXEC, fd, tmp);
break;
case F_DUP2FD:
tmp = arg;
error = kern_dup(td, FDDUP_FIXED, 0, fd, tmp);
break;
case F_DUP2FD_CLOEXEC:
tmp = arg;
error = kern_dup(td, FDDUP_FIXED, FDDUP_FLAG_CLOEXEC, fd, tmp);
break;
case F_GETFD:
error = EBADF;
FILEDESC_SLOCK(fdp);
fde = fdeget_locked(fdp, fd);
if (fde != NULL) {
td->td_retval[0] =
(fde->fde_flags & UF_EXCLOSE) ? FD_CLOEXEC : 0;
error = 0;
}
FILEDESC_SUNLOCK(fdp);
break;
case F_SETFD:
error = EBADF;
FILEDESC_XLOCK(fdp);
fde = fdeget_locked(fdp, fd);
if (fde != NULL) {
fde->fde_flags = (fde->fde_flags & ~UF_EXCLOSE) |
(arg & FD_CLOEXEC ? UF_EXCLOSE : 0);
error = 0;
}
FILEDESC_XUNLOCK(fdp);
break;
case F_GETFL:
error = fget_fcntl(td, fd, &cap_fcntl_rights, F_GETFL, &fp);
if (error != 0)
break;
td->td_retval[0] = OFLAGS(fp->f_flag);
fdrop(fp, td);
break;
case F_SETFL:
error = fget_fcntl(td, fd, &cap_fcntl_rights, F_SETFL, &fp);
if (error != 0)
break;
do {
tmp = flg = fp->f_flag;
tmp &= ~FCNTLFLAGS;
tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS;
} while(atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0);
tmp = fp->f_flag & FNONBLOCK;
error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
if (error != 0) {
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;
}
atomic_clear_int(&fp->f_flag, FNONBLOCK);
tmp = 0;
(void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
fdrop(fp, td);
break;
case F_GETOWN:
error = fget_fcntl(td, fd, &cap_fcntl_rights, F_GETOWN, &fp);
if (error != 0)
break;
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:
error = fget_fcntl(td, fd, &cap_fcntl_rights, F_SETOWN, &fp);
if (error != 0)
break;
tmp = arg;
error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td);
fdrop(fp, td);
break;
case F_SETLK_REMOTE:
error = priv_check(td, PRIV_NFS_LOCKD);
if (error != 0)
return (error);
flg = F_REMOTE;
goto do_setlk;
case F_SETLKW:
flg |= F_WAIT;
/* FALLTHROUGH F_SETLK */
case F_SETLK:
do_setlk:
flp = (struct flock *)arg;
if ((flg & F_REMOTE) != 0 && flp->l_sysid == 0) {
error = EINVAL;
break;
}
error = fget_unlocked(fdp, fd, &cap_flock_rights, &fp);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
error = EBADF;
fdrop(fp, td);
break;
}
if (flp->l_whence == SEEK_CUR) {
foffset = foffset_get(fp);
if (foffset < 0 ||
(flp->l_start > 0 &&
foffset > OFF_MAX - flp->l_start)) {
error = EOVERFLOW;
fdrop(fp, td);
break;
}
flp->l_start += foffset;
}
vp = fp->f_vnode;
switch (flp->l_type) {
case F_RDLCK:
if ((fp->f_flag & FREAD) == 0) {
error = EBADF;
break;
}
if ((p->p_leader->p_flag & P_ADVLOCK) == 0) {
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;
}
if ((p->p_leader->p_flag & P_ADVLOCK) == 0) {
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, flg);
break;
case F_UNLCKSYS:
if (flg != F_REMOTE) {
error = EINVAL;
break;
}
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
F_UNLCKSYS, flp, flg);
break;
default:
error = EINVAL;
break;
}
if (error != 0 || flp->l_type == F_UNLCK ||
flp->l_type == F_UNLCKSYS) {
fdrop(fp, td);
break;
}
/*
* Check for a race with close.
*
* The vnode is now advisory locked (or unlocked, but this case
* is not really important) as the caller requested.
* We had to drop the filedesc lock, so we need to recheck if
* the descriptor is still valid, because if it was closed
* in the meantime we need to remove advisory lock from the
* vnode - close on any descriptor leading to an advisory
* locked vnode, removes that lock.
* We will return 0 on purpose in that case, as the result of
* successful advisory lock might have been externally visible
* already. This is fine - effectively we pretend to the caller
* that the closing thread was a bit slower and that the
* advisory lock succeeded before the close.
*/
error = fget_unlocked(fdp, fd, &cap_no_rights, &fp2);
if (error != 0) {
fdrop(fp, td);
break;
}
if (fp != fp2) {
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);
}
fdrop(fp, td);
fdrop(fp2, td);
break;
case F_GETLK:
error = fget_unlocked(fdp, fd, &cap_flock_rights, &fp);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
error = EBADF;
fdrop(fp, td);
break;
}
flp = (struct flock *)arg;
if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK &&
flp->l_type != F_UNLCK) {
error = EINVAL;
fdrop(fp, td);
break;
}
if (flp->l_whence == SEEK_CUR) {
foffset = foffset_get(fp);
if ((flp->l_start > 0 &&
foffset > OFF_MAX - flp->l_start) ||
(flp->l_start < 0 &&
foffset < OFF_MIN - flp->l_start)) {
error = EOVERFLOW;
fdrop(fp, td);
break;
}
flp->l_start += foffset;
}
vp = fp->f_vnode;
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp,
F_POSIX);
fdrop(fp, td);
break;
case F_ADD_SEALS:
error = fget_unlocked(fdp, fd, &cap_no_rights, &fp);
if (error != 0)
break;
error = fo_add_seals(fp, arg);
fdrop(fp, td);
break;
case F_GET_SEALS:
error = fget_unlocked(fdp, fd, &cap_no_rights, &fp);
if (error != 0)
break;
if (fo_get_seals(fp, &seals) == 0)
td->td_retval[0] = seals;
else
error = EINVAL;
fdrop(fp, td);
break;
case F_RDAHEAD:
arg = arg ? 128 * 1024: 0;
/* FALLTHROUGH */
case F_READAHEAD:
error = fget_unlocked(fdp, fd, &cap_no_rights, &fp);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
fdrop(fp, td);
error = EBADF;
break;
}
vp = fp->f_vnode;
if (vp->v_type != VREG) {
fdrop(fp, td);
error = ENOTTY;
break;
}
/*
* Exclusive lock synchronizes against f_seqcount reads and
* writes in sequential_heuristic().
*/
error = vn_lock(vp, LK_EXCLUSIVE);
if (error != 0) {
fdrop(fp, td);
break;
}
if (arg >= 0) {
bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize;
arg = MIN(arg, INT_MAX - bsize + 1);
fp->f_seqcount[UIO_READ] = MIN(IO_SEQMAX,
(arg + bsize - 1) / bsize);
atomic_set_int(&fp->f_flag, FRDAHEAD);
} else {
atomic_clear_int(&fp->f_flag, FRDAHEAD);
}
VOP_UNLOCK(vp);
fdrop(fp, td);
break;
case F_ISUNIONSTACK:
/*
* Check if the vnode is part of a union stack (either the
* "union" flag from mount(2) or unionfs).
*
* Prior to introduction of this op libc's readdir would call
* fstatfs(2), in effect unnecessarily copying kilobytes of
* data just to check fs name and a mount flag.
*
* Fixing the code to handle everything in the kernel instead
* is a non-trivial endeavor and has low priority, thus this
* horrible kludge facilitates the current behavior in a much
* cheaper manner until someone(tm) sorts this out.
*/
error = fget_unlocked(fdp, fd, &cap_no_rights, &fp);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
fdrop(fp, td);
error = EBADF;
break;
}
vp = fp->f_vnode;
/*
* Since we don't prevent dooming the vnode even non-null mp
* found can become immediately stale. This is tolerable since
* mount points are type-stable (providing safe memory access)
* and any vfs op on this vnode going forward will return an
* error (meaning return value in this case is meaningless).
*/
mp = atomic_load_ptr(&vp->v_mount);
if (__predict_false(mp == NULL)) {
fdrop(fp, td);
error = EBADF;
break;
}
td->td_retval[0] = 0;
if (mp->mnt_kern_flag & MNTK_UNIONFS ||
mp->mnt_flag & MNT_UNION)
td->td_retval[0] = 1;
fdrop(fp, td);
break;
default:
error = EINVAL;
break;
}
return (error);
}
static int
getmaxfd(struct thread *td)
{
return (min((int)lim_cur(td, RLIMIT_NOFILE), maxfilesperproc));
}
/*
* Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD).
*/
int
kern_dup(struct thread *td, u_int mode, int flags, int old, int new)
{
struct filedesc *fdp;
struct filedescent *oldfde, *newfde;
struct proc *p;
struct file *delfp;
u_long *oioctls, *nioctls;
int error, maxfd;
p = td->td_proc;
fdp = p->p_fd;
oioctls = NULL;
MPASS((flags & ~(FDDUP_FLAG_CLOEXEC)) == 0);
MPASS(mode < FDDUP_LASTMODE);
AUDIT_ARG_FD(old);
/* XXXRW: if (flags & FDDUP_FIXED) AUDIT_ARG_FD2(new); */
/*
* Verify we have a valid descriptor to dup from and possibly to
* dup to. Unlike dup() and dup2(), fcntl()'s F_DUPFD should
* return EINVAL when the new descriptor is out of bounds.
*/
if (old < 0)
return (EBADF);
if (new < 0)
return (mode == FDDUP_FCNTL ? EINVAL : EBADF);
maxfd = getmaxfd(td);
if (new >= maxfd)
return (mode == FDDUP_FCNTL ? EINVAL : EBADF);
error = EBADF;
FILEDESC_XLOCK(fdp);
if (fget_locked(fdp, old) == NULL)
goto unlock;
if ((mode == FDDUP_FIXED || mode == FDDUP_MUSTREPLACE) && old == new) {
td->td_retval[0] = new;
if (flags & FDDUP_FLAG_CLOEXEC)
fdp->fd_ofiles[new].fde_flags |= UF_EXCLOSE;
error = 0;
goto unlock;
}
oldfde = &fdp->fd_ofiles[old];
if (!fhold(oldfde->fde_file))
goto unlock;
/*
* 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.
*/
switch (mode) {
case FDDUP_NORMAL:
case FDDUP_FCNTL:
if ((error = fdalloc(td, new, &new)) != 0) {
fdrop(oldfde->fde_file, td);
goto unlock;
}
break;
case FDDUP_MUSTREPLACE:
/* Target file descriptor must exist. */
if (fget_locked(fdp, new) == NULL) {
fdrop(oldfde->fde_file, td);
goto unlock;
}
break;
case FDDUP_FIXED:
if (new >= fdp->fd_nfiles) {
/*
* The resource limits are here instead of e.g.
* fdalloc(), because the file descriptor table may be
* shared between processes, so we can't really use
* racct_add()/racct_sub(). Instead of counting the
* number of actually allocated descriptors, just put
* the limit on the size of the file descriptor table.
*/
#ifdef RACCT
if (RACCT_ENABLED()) {
error = racct_set_unlocked(p, RACCT_NOFILE, new + 1);
if (error != 0) {
error = EMFILE;
fdrop(oldfde->fde_file, td);
goto unlock;
}
}
#endif
fdgrowtable_exp(fdp, new + 1);
}
if (!fdisused(fdp, new))
fdused(fdp, new);
break;
default:
KASSERT(0, ("%s unsupported mode %d", __func__, mode));
}
KASSERT(old != new, ("new fd is same as old"));
newfde = &fdp->fd_ofiles[new];
delfp = newfde->fde_file;
nioctls = filecaps_copy_prep(&oldfde->fde_caps);
/*
* Duplicate the source descriptor.
*/
#ifdef CAPABILITIES
seqc_write_begin(&newfde->fde_seqc);
#endif
oioctls = filecaps_free_prep(&newfde->fde_caps);
memcpy(newfde, oldfde, fde_change_size);
filecaps_copy_finish(&oldfde->fde_caps, &newfde->fde_caps,
nioctls);
if ((flags & FDDUP_FLAG_CLOEXEC) != 0)
newfde->fde_flags = oldfde->fde_flags | UF_EXCLOSE;
else
newfde->fde_flags = oldfde->fde_flags & ~UF_EXCLOSE;
#ifdef CAPABILITIES
seqc_write_end(&newfde->fde_seqc);
#endif
td->td_retval[0] = new;
error = 0;
if (delfp != NULL) {
(void) closefp(fdp, new, delfp, td, 1);
FILEDESC_UNLOCK_ASSERT(fdp);
} else {
unlock:
FILEDESC_XUNLOCK(fdp);
}
filecaps_free_finish(oioctls);
return (error);
}
static void
sigiofree(struct sigio *sigio)
{
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO);
}
static struct sigio *
funsetown_locked(struct sigio *sigio)
{
struct proc *p;
struct pgrp *pg;
SIGIO_ASSERT_LOCKED();
if (sigio == NULL)
return (NULL);
*(sigio->sio_myref) = NULL;
if (sigio->sio_pgid < 0) {
pg = sigio->sio_pgrp;
PGRP_LOCK(pg);
SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
sigio, sio_pgsigio);
PGRP_UNLOCK(pg);
} else {
p = sigio->sio_proc;
PROC_LOCK(p);
SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
sigio, sio_pgsigio);
PROC_UNLOCK(p);
}
return (sigio);
}
/*
* 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(struct sigio **sigiop)
{
struct sigio *sigio;
/* Racy check, consumers must provide synchronization. */
if (*sigiop == NULL)
return;
SIGIO_LOCK();
sigio = funsetown_locked(*sigiop);
SIGIO_UNLOCK();
if (sigio != NULL)
sigiofree(sigio);
}
/*
* Free a list of sigio structures. The caller must ensure that new sigio
* structures cannot be added after this point. For process groups this is
* guaranteed using the proctree lock; for processes, the P_WEXIT flag serves
* as an interlock.
*/
void
funsetownlst(struct sigiolst *sigiolst)
{
struct proc *p;
struct pgrp *pg;
struct sigio *sigio, *tmp;
/* Racy check. */
sigio = SLIST_FIRST(sigiolst);
if (sigio == NULL)
return;
p = NULL;
pg = NULL;
SIGIO_LOCK();
sigio = SLIST_FIRST(sigiolst);
if (sigio == NULL) {
SIGIO_UNLOCK();
return;
}
/*
* Every entry of the list should belong to a single proc or pgrp.
*/
if (sigio->sio_pgid < 0) {
pg = sigio->sio_pgrp;
sx_assert(&proctree_lock, SX_XLOCKED);
PGRP_LOCK(pg);
} else /* if (sigio->sio_pgid > 0) */ {
p = sigio->sio_proc;
PROC_LOCK(p);
KASSERT((p->p_flag & P_WEXIT) != 0,
("%s: process %p is not exiting", __func__, p));
}
SLIST_FOREACH(sigio, sigiolst, sio_pgsigio) {
*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"));
} 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"));
}
}
if (pg != NULL)
PGRP_UNLOCK(pg);
else
PROC_UNLOCK(p);
SIGIO_UNLOCK();
SLIST_FOREACH_SAFE(sigio, sigiolst, sio_pgsigio, tmp)
sigiofree(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(pid_t pgid, struct sigio **sigiop)
{
struct proc *proc;
struct pgrp *pgrp;
struct sigio *osigio, *sigio;
int ret;
if (pgid == 0) {
funsetown(sigiop);
return (0);
}
ret = 0;
sigio = malloc(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);
SIGIO_LOCK();
osigio = funsetown_locked(*sigiop);
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.
*/
if (proc->p_session != curthread->td_proc->p_session) {
PROC_UNLOCK(proc);
ret = EPERM;
goto fail;
}
sigio->sio_proc = proc;
SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
PROC_UNLOCK(proc);
} else /* if (pgid < 0) */ {
pgrp = pgfind(-pgid);
if (pgrp == 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.
*/
if (pgrp->pg_session != curthread->td_proc->p_session) {
PGRP_UNLOCK(pgrp);
ret = EPERM;
goto fail;
}
SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
sigio->sio_pgrp = pgrp;
PGRP_UNLOCK(pgrp);
}
sx_sunlock(&proctree_lock);
*sigiop = sigio;
SIGIO_UNLOCK();
if (osigio != NULL)
sigiofree(osigio);
return (0);
fail:
SIGIO_UNLOCK();
sx_sunlock(&proctree_lock);
sigiofree(sigio);
if (osigio != NULL)
sigiofree(osigio);
return (ret);
}
/*
* This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
*/
pid_t
fgetown(struct sigio **sigiop)
{
pid_t pgid;
SIGIO_LOCK();
pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0;
SIGIO_UNLOCK();
return (pgid);
}
/*
* Function drops the filedesc lock on return.
*/
static int
closefp(struct filedesc *fdp, int fd, struct file *fp, struct thread *td,
int holdleaders)
{
int error;
FILEDESC_XLOCK_ASSERT(fdp);
if (holdleaders) {
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++;
} else {
holdleaders = 0;
}
}
/*
* We now hold the fp reference that used to be owned by the
* descriptor array. We have to unlock the FILEDESC *AFTER*
* knote_fdclose to prevent a race of the fd getting opened, a knote
* added, and deleteing a knote for the new fd.
*/
if (__predict_false(!TAILQ_EMPTY(&fdp->fd_kqlist)))
knote_fdclose(td, fd);
/*
* We need to notify mqueue if the object is of type mqueue.
*/
if (__predict_false(fp->f_type == DTYPE_MQUEUE))
mq_fdclose(td, fd, fp);
FILEDESC_XUNLOCK(fdp);
error = closef(fp, td);
if (holdleaders) {
FILEDESC_XLOCK(fdp);
fdp->fd_holdleaderscount--;
if (fdp->fd_holdleaderscount == 0 &&
fdp->fd_holdleaderswakeup != 0) {
fdp->fd_holdleaderswakeup = 0;
wakeup(&fdp->fd_holdleaderscount);
}
FILEDESC_XUNLOCK(fdp);
}
return (error);
}
/*
* Close a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct close_args {
int fd;
};
#endif
/* ARGSUSED */
int
sys_close(struct thread *td, struct close_args *uap)
{
return (kern_close(td, uap->fd));
}
int
kern_close(struct thread *td, int fd)
{
struct filedesc *fdp;
struct file *fp;
fdp = td->td_proc->p_fd;
AUDIT_SYSCLOSE(td, fd);
FILEDESC_XLOCK(fdp);
if ((fp = fget_locked(fdp, fd)) == NULL) {
FILEDESC_XUNLOCK(fdp);
return (EBADF);
}
fdfree(fdp, fd);
/* closefp() drops the FILEDESC lock for us. */
return (closefp(fdp, fd, fp, td, 1));
}
int
kern_close_range(struct thread *td, u_int lowfd, u_int highfd)
{
struct filedesc *fdp;
int fd, ret, lastfile;
ret = 0;
fdp = td->td_proc->p_fd;
FILEDESC_SLOCK(fdp);
/*
* Check this prior to clamping; closefrom(3) with only fd 0, 1, and 2
* open should not be a usage error. From a close_range() perspective,
* close_range(3, ~0U, 0) in the same scenario should also likely not
* be a usage error as all fd above 3 are in-fact already closed.
*/
if (highfd < lowfd) {
ret = EINVAL;
goto out;
}
/*
* If lastfile == -1, we're dealing with either a fresh file
* table or one in which every fd has been closed. Just return
* successful; there's nothing left to do.
*/
lastfile = fdlastfile(fdp);
if (lastfile == -1)
goto out;
/* Clamped to [lowfd, lastfile] */
highfd = MIN(highfd, lastfile);
for (fd = lowfd; fd <= highfd; fd++) {
if (fdp->fd_ofiles[fd].fde_file != NULL) {
FILEDESC_SUNLOCK(fdp);
(void)kern_close(td, fd);
FILEDESC_SLOCK(fdp);
}
}
out:
FILEDESC_SUNLOCK(fdp);
return (ret);
}
#ifndef _SYS_SYSPROTO_H_
struct close_range_args {
u_int lowfd;
u_int highfd;
int flags;
};
#endif
int
sys_close_range(struct thread *td, struct close_range_args *uap)
{
/* No flags currently defined */
if (uap->flags != 0)
return (EINVAL);
return (kern_close_range(td, uap->lowfd, uap->highfd));
}
#ifdef COMPAT_FREEBSD12
/*
* Close open file descriptors.
*/
#ifndef _SYS_SYSPROTO_H_
struct freebsd12_closefrom_args {
int lowfd;
};
#endif
/* ARGSUSED */
int
freebsd12_closefrom(struct thread *td, struct freebsd12_closefrom_args *uap)
{
u_int lowfd;
AUDIT_ARG_FD(uap->lowfd);
/*
* Treat negative starting file descriptor values identical to
* closefrom(0) which closes all files.
*/
lowfd = MAX(0, uap->lowfd);
return (kern_close_range(td, lowfd, ~0U));
}
#endif /* COMPAT_FREEBSD12 */
#if defined(COMPAT_43)
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct ofstat_args {
int fd;
struct ostat *sb;
};
#endif
/* ARGSUSED */
int
ofstat(struct thread *td, struct ofstat_args *uap)
{
struct ostat oub;
struct stat ub;
int error;
error = kern_fstat(td, uap->fd, &ub);
if (error == 0) {
cvtstat(&ub, &oub);
error = copyout(&oub, uap->sb, sizeof(oub));
}
return (error);
}
#endif /* COMPAT_43 */
#if defined(COMPAT_FREEBSD11)
int
freebsd11_fstat(struct thread *td, struct freebsd11_fstat_args *uap)
{
struct stat sb;
struct freebsd11_stat osb;
int error;
error = kern_fstat(td, uap->fd, &sb);
if (error != 0)
return (error);
error = freebsd11_cvtstat(&sb, &osb);
if (error == 0)
error = copyout(&osb, uap->sb, sizeof(osb));
return (error);
}
#endif /* COMPAT_FREEBSD11 */
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct fstat_args {
int fd;
struct stat *sb;
};
#endif
/* ARGSUSED */
int
sys_fstat(struct thread *td, struct fstat_args *uap)
{
struct stat ub;
int error;
error = kern_fstat(td, uap->fd, &ub);
if (error == 0)
error = copyout(&ub, uap->sb, sizeof(ub));
return (error);
}
int
kern_fstat(struct thread *td, int fd, struct stat *sbp)
{
struct file *fp;
int error;
AUDIT_ARG_FD(fd);
error = fget(td, fd, &cap_fstat_rights, &fp);
if (__predict_false(error != 0))
return (error);
AUDIT_ARG_FILE(td->td_proc, fp);
error = fo_stat(fp, sbp, td->td_ucred, td);
fdrop(fp, td);
#ifdef __STAT_TIME_T_EXT
sbp->st_atim_ext = 0;
sbp->st_mtim_ext = 0;
sbp->st_ctim_ext = 0;
sbp->st_btim_ext = 0;
#endif
#ifdef KTRACE
if (KTRPOINT(td, KTR_STRUCT))
ktrstat_error(sbp, error);
#endif
return (error);
}
#if defined(COMPAT_FREEBSD11)
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct freebsd11_nfstat_args {
int fd;
struct nstat *sb;
};
#endif
/* ARGSUSED */
int
freebsd11_nfstat(struct thread *td, struct freebsd11_nfstat_args *uap)
{
struct nstat nub;
struct stat ub;
int error;
error = kern_fstat(td, uap->fd, &ub);
if (error == 0) {
freebsd11_cvtnstat(&ub, &nub);
error = copyout(&nub, uap->sb, sizeof(nub));
}
return (error);
}
#endif /* COMPAT_FREEBSD11 */
/*
* Return pathconf information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct fpathconf_args {
int fd;
int name;
};
#endif
/* ARGSUSED */
int
sys_fpathconf(struct thread *td, struct fpathconf_args *uap)
{
long value;
int error;
error = kern_fpathconf(td, uap->fd, uap->name, &value);
if (error == 0)
td->td_retval[0] = value;
return (error);
}
int
kern_fpathconf(struct thread *td, int fd, int name, long *valuep)
{
struct file *fp;
struct vnode *vp;
int error;
error = fget(td, fd, &cap_fpathconf_rights, &fp);
if (error != 0)
return (error);
if (name == _PC_ASYNC_IO) {
*valuep = _POSIX_ASYNCHRONOUS_IO;
goto out;
}
vp = fp->f_vnode;
if (vp != NULL) {
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_PATHCONF(vp, name, valuep);
VOP_UNLOCK(vp);
} else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) {
if (name != _PC_PIPE_BUF) {
error = EINVAL;
} else {
*valuep = PIPE_BUF;
error = 0;
}
} else {
error = EOPNOTSUPP;
}
out:
fdrop(fp, td);
return (error);
}
/*
* Copy filecaps structure allocating memory for ioctls array if needed.
*
* The last parameter indicates whether the fdtable is locked. If it is not and
* ioctls are encountered, copying fails and the caller must lock the table.
*
* Note that if the table was not locked, the caller has to check the relevant
* sequence counter to determine whether the operation was successful.
*/
bool
filecaps_copy(const struct filecaps *src, struct filecaps *dst, bool locked)
{
size_t size;
if (src->fc_ioctls != NULL && !locked)
return (false);
memcpy(dst, src, sizeof(*src));
if (src->fc_ioctls == NULL)
return (true);
KASSERT(src->fc_nioctls > 0,
("fc_ioctls != NULL, but fc_nioctls=%hd", src->fc_nioctls));
size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls;
dst->fc_ioctls = malloc(size, M_FILECAPS, M_WAITOK);
memcpy(dst->fc_ioctls, src->fc_ioctls, size);
return (true);
}
static u_long *
filecaps_copy_prep(const struct filecaps *src)
{
u_long *ioctls;
size_t size;
if (__predict_true(src->fc_ioctls == NULL))
return (NULL);
KASSERT(src->fc_nioctls > 0,
("fc_ioctls != NULL, but fc_nioctls=%hd", src->fc_nioctls));
size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls;
ioctls = malloc(size, M_FILECAPS, M_WAITOK);
return (ioctls);
}
static void
filecaps_copy_finish(const struct filecaps *src, struct filecaps *dst,
u_long *ioctls)
{
size_t size;
*dst = *src;
if (__predict_true(src->fc_ioctls == NULL)) {
MPASS(ioctls == NULL);
return;
}
size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls;
dst->fc_ioctls = ioctls;
bcopy(src->fc_ioctls, dst->fc_ioctls, size);
}
/*
* Move filecaps structure to the new place and clear the old place.
*/
void
filecaps_move(struct filecaps *src, struct filecaps *dst)
{
*dst = *src;
bzero(src, sizeof(*src));
}
/*
* Fill the given filecaps structure with full rights.
*/
static void
filecaps_fill(struct filecaps *fcaps)
{
CAP_ALL(&fcaps->fc_rights);
fcaps->fc_ioctls = NULL;
fcaps->fc_nioctls = -1;
fcaps->fc_fcntls = CAP_FCNTL_ALL;
}
/*
* Free memory allocated within filecaps structure.
*/
void
filecaps_free(struct filecaps *fcaps)
{
free(fcaps->fc_ioctls, M_FILECAPS);
bzero(fcaps, sizeof(*fcaps));
}
static u_long *
filecaps_free_prep(struct filecaps *fcaps)
{
u_long *ioctls;
ioctls = fcaps->fc_ioctls;
bzero(fcaps, sizeof(*fcaps));
return (ioctls);
}
static void
filecaps_free_finish(u_long *ioctls)
{
free(ioctls, M_FILECAPS);
}
/*
* Validate the given filecaps structure.
*/
static void
filecaps_validate(const struct filecaps *fcaps, const char *func)
{
KASSERT(cap_rights_is_valid(&fcaps->fc_rights),
("%s: invalid rights", func));
KASSERT((fcaps->fc_fcntls & ~CAP_FCNTL_ALL) == 0,
("%s: invalid fcntls", func));
KASSERT(fcaps->fc_fcntls == 0 ||
cap_rights_is_set(&fcaps->fc_rights, CAP_FCNTL),
("%s: fcntls without CAP_FCNTL", func));
KASSERT(fcaps->fc_ioctls != NULL ? fcaps->fc_nioctls > 0 :
(fcaps->fc_nioctls == -1 || fcaps->fc_nioctls == 0),
("%s: invalid ioctls", func));
KASSERT(fcaps->fc_nioctls == 0 ||
cap_rights_is_set(&fcaps->fc_rights, CAP_IOCTL),
("%s: ioctls without CAP_IOCTL", func));
}
static void
fdgrowtable_exp(struct filedesc *fdp, int nfd)
{
int nfd1;
FILEDESC_XLOCK_ASSERT(fdp);
nfd1 = fdp->fd_nfiles * 2;
if (nfd1 < nfd)
nfd1 = nfd;
fdgrowtable(fdp, nfd1);
}
/*
* Grow the file table to accommodate (at least) nfd descriptors.
*/
static void
fdgrowtable(struct filedesc *fdp, int nfd)
{
struct filedesc0 *fdp0;
struct freetable *ft;
struct fdescenttbl *ntable;
struct fdescenttbl *otable;
int nnfiles, onfiles;
NDSLOTTYPE *nmap, *omap;
KASSERT(fdp->fd_nfiles > 0, ("zero-length file table"));
/* save old values */
onfiles = fdp->fd_nfiles;
otable = fdp->fd_files;
omap = fdp->fd_map;
/* compute the size of the new table */
nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */
if (nnfiles <= onfiles)
/* the table is already large enough */
return;
/*
* Allocate a new table. We need enough space for the number of
* entries, file entries themselves and the struct freetable we will use
* when we decommission the table and place it on the freelist.
* We place the struct freetable in the middle so we don't have
* to worry about padding.
*/
ntable = malloc(offsetof(struct fdescenttbl, fdt_ofiles) +
nnfiles * sizeof(ntable->fdt_ofiles[0]) +
sizeof(struct freetable),
M_FILEDESC, M_ZERO | M_WAITOK);
/* copy the old data */
ntable->fdt_nfiles = nnfiles;
memcpy(ntable->fdt_ofiles, otable->fdt_ofiles,
onfiles * sizeof(ntable->fdt_ofiles[0]));
/*
* Allocate a new map only if the old is not large enough. It will
* grow at a slower rate than the table as it can map more
* entries than the table can hold.
*/
if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) {
nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC,
M_ZERO | M_WAITOK);
/* copy over the old data and update the pointer */
memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap));
fdp->fd_map = nmap;
}
/*
* Make sure that ntable is correctly initialized before we replace
* fd_files poiner. Otherwise fget_unlocked() may see inconsistent
* data.
*/
atomic_store_rel_ptr((volatile void *)&fdp->fd_files, (uintptr_t)ntable);
/*
* Do not free the old file table, as some threads may still
* reference entries within it. Instead, place it on a freelist
* which will be processed when the struct filedesc is released.
*
* Note that if onfiles == NDFILE, we're dealing with the original
* static allocation contained within (struct filedesc0 *)fdp,
* which must not be freed.
*/
if (onfiles > NDFILE) {
ft = (struct freetable *)&otable->fdt_ofiles[onfiles];
fdp0 = (struct filedesc0 *)fdp;
ft->ft_table = otable;
SLIST_INSERT_HEAD(&fdp0->fd_free, ft, ft_next);
}
/*
* The map does not have the same possibility of threads still
* holding references to it. So always free it as long as it
* does not reference the original static allocation.
*/
if (NDSLOTS(onfiles) > NDSLOTS(NDFILE))
free(omap, M_FILEDESC);
}
/*
* Allocate a file descriptor for the process.
*/
int
fdalloc(struct thread *td, int minfd, int *result)
{
struct proc *p = td->td_proc;
struct filedesc *fdp = p->p_fd;
int fd, maxfd, allocfd;
#ifdef RACCT
int error;
#endif
FILEDESC_XLOCK_ASSERT(fdp);
if (fdp->fd_freefile > minfd)
minfd = fdp->fd_freefile;
maxfd = getmaxfd(td);
/*
* Search the bitmap for a free descriptor starting at minfd.
* If none is found, grow the file table.
*/
fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
if (__predict_false(fd >= maxfd))
return (EMFILE);
if (__predict_false(fd >= fdp->fd_nfiles)) {
allocfd = min(fd * 2, maxfd);
#ifdef RACCT
if (RACCT_ENABLED()) {
error = racct_set_unlocked(p, RACCT_NOFILE, allocfd);
if (error != 0)
return (EMFILE);
}
#endif
/*
* fd is already equal to first free descriptor >= minfd, so
* we only need to grow the table and we are done.
*/
fdgrowtable_exp(fdp, allocfd);
}
/*
* Perform some sanity checks, then mark the file descriptor as
* used and return it to the caller.
*/
KASSERT(fd >= 0 && fd < min(maxfd, fdp->fd_nfiles),
("invalid descriptor %d", fd));
KASSERT(!fdisused(fdp, fd),
("fd_first_free() returned non-free descriptor"));
KASSERT(fdp->fd_ofiles[fd].fde_file == NULL,
("file descriptor isn't free"));
fdused(fdp, fd);
*result = fd;
return (0);
}
/*
* Allocate n file descriptors for the process.
*/
int
fdallocn(struct thread *td, int minfd, int *fds, int n)
{
struct proc *p = td->td_proc;
struct filedesc *fdp = p->p_fd;
int i;
FILEDESC_XLOCK_ASSERT(fdp);
for (i = 0; i < n; i++)
if (fdalloc(td, 0, &fds[i]) != 0)
break;
if (i < n) {
for (i--; i >= 0; i--)
fdunused(fdp, fds[i]);
return (EMFILE);
}
return (0);
}
/*
* Create a new open file structure and allocate a file descriptor 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 preempted and the entry in the descriptor table closed after we
* release the FILEDESC lock.
*/
int
falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, int flags,
struct filecaps *fcaps)
{
struct file *fp;
int error, fd;
error = falloc_noinstall(td, &fp);
if (error)
return (error); /* no reference held on error */
error = finstall(td, fp, &fd, flags, fcaps);
if (error) {
fdrop(fp, td); /* one reference (fp only) */
return (error);
}
if (resultfp != NULL)
*resultfp = fp; /* copy out result */
else
fdrop(fp, td); /* release local reference */
if (resultfd != NULL)
*resultfd = fd;
return (0);
}
/*
* Create a new open file structure without allocating a file descriptor.
*/
int
falloc_noinstall(struct thread *td, struct file **resultfp)
{
struct file *fp;
int maxuserfiles = maxfiles - (maxfiles / 20);
int openfiles_new;
static struct timeval lastfail;
static int curfail;
KASSERT(resultfp != NULL, ("%s: resultfp == NULL", __func__));
openfiles_new = atomic_fetchadd_int(&openfiles, 1) + 1;
if ((openfiles_new >= maxuserfiles &&
priv_check(td, PRIV_MAXFILES) != 0) ||
openfiles_new >= maxfiles) {
atomic_subtract_int(&openfiles, 1);
if (ppsratecheck(&lastfail, &curfail, 1)) {
printf("kern.maxfiles limit exceeded by uid %i, (%s) "
"please see tuning(7).\n", td->td_ucred->cr_ruid, td->td_proc->p_comm);
}
return (ENFILE);
}
fp = uma_zalloc(file_zone, M_WAITOK);
bzero(fp, sizeof(*fp));
refcount_init(&fp->f_count, 1);
fp->f_cred = crhold(td->td_ucred);
fp->f_ops = &badfileops;
*resultfp = fp;
return (0);
}
/*
* Install a file in a file descriptor table.
*/
void
_finstall(struct filedesc *fdp, struct file *fp, int fd, int flags,
struct filecaps *fcaps)
{
struct filedescent *fde;
MPASS(fp != NULL);
if (fcaps != NULL)
filecaps_validate(fcaps, __func__);
FILEDESC_XLOCK_ASSERT(fdp);
fde = &fdp->fd_ofiles[fd];
#ifdef CAPABILITIES
seqc_write_begin(&fde->fde_seqc);
#endif
fde->fde_file = fp;
fde->fde_flags = (flags & O_CLOEXEC) != 0 ? UF_EXCLOSE : 0;
if (fcaps != NULL)
filecaps_move(fcaps, &fde->fde_caps);
else
filecaps_fill(&fde->fde_caps);
#ifdef CAPABILITIES
seqc_write_end(&fde->fde_seqc);
#endif
}
int
finstall(struct thread *td, struct file *fp, int *fd, int flags,
struct filecaps *fcaps)
{
struct filedesc *fdp = td->td_proc->p_fd;
int error;
MPASS(fd != NULL);
if (!fhold(fp))
return (EBADF);
FILEDESC_XLOCK(fdp);
error = fdalloc(td, 0, fd);
if (__predict_false(error != 0)) {
FILEDESC_XUNLOCK(fdp);
fdrop(fp, td);
return (error);
}
_finstall(fdp, fp, *fd, flags, fcaps);
FILEDESC_XUNLOCK(fdp);
return (0);
}
/*
* Build a new filedesc structure from another.
* Copy the current, root, and jail root vnode references.
*
* If fdp is not NULL, return with it shared locked.
*/
struct filedesc *
fdinit(struct filedesc *fdp, bool prepfiles, int *lastfile)
{
struct filedesc0 *newfdp0;
struct filedesc *newfdp;
struct pwd *newpwd;
if (prepfiles)
MPASS(lastfile != NULL);
else
MPASS(lastfile == NULL);
newfdp0 = uma_zalloc(filedesc0_zone, M_WAITOK | M_ZERO);
newfdp = &newfdp0->fd_fd;
/* Create the file descriptor table. */
FILEDESC_LOCK_INIT(newfdp);
refcount_init(&newfdp->fd_refcnt, 1);
refcount_init(&newfdp->fd_holdcnt, 1);
newfdp->fd_cmask = CMASK;
newfdp->fd_map = newfdp0->fd_dmap;
newfdp->fd_files = (struct fdescenttbl *)&newfdp0->fd_dfiles;
newfdp->fd_files->fdt_nfiles = NDFILE;
if (fdp == NULL) {
newpwd = pwd_alloc();
smr_serialized_store(&newfdp->fd_pwd, newpwd, true);
return (newfdp);
}
FILEDESC_SLOCK(fdp);
newpwd = pwd_hold_filedesc(fdp);
smr_serialized_store(&newfdp->fd_pwd, newpwd, true);
if (!prepfiles) {
FILEDESC_SUNLOCK(fdp);
return (newfdp);
}
for (;;) {
*lastfile = fdlastfile(fdp);
if (*lastfile < newfdp->fd_nfiles)
break;
FILEDESC_SUNLOCK(fdp);
fdgrowtable(newfdp, *lastfile + 1);
FILEDESC_SLOCK(fdp);
}
return (newfdp);
}
static struct filedesc *
fdhold(struct proc *p)
{
struct filedesc *fdp;
PROC_LOCK_ASSERT(p, MA_OWNED);
fdp = p->p_fd;
if (fdp != NULL)
refcount_acquire(&fdp->fd_holdcnt);
return (fdp);
}
static void
fddrop(struct filedesc *fdp)
{
if (fdp->fd_holdcnt > 1) {
if (refcount_release(&fdp->fd_holdcnt) == 0)
return;
}
FILEDESC_LOCK_DESTROY(fdp);
uma_zfree(filedesc0_zone, fdp);
}
/*
* Share a filedesc structure.
*/
struct filedesc *
fdshare(struct filedesc *fdp)
{
refcount_acquire(&fdp->fd_refcnt);
return (fdp);
}
/*
* Unshare a filedesc structure, if necessary by making a copy
*/
void
fdunshare(struct thread *td)
{
struct filedesc *tmp;
struct proc *p = td->td_proc;
if (p->p_fd->fd_refcnt == 1)
return;
tmp = fdcopy(p->p_fd);
fdescfree(td);
p->p_fd = tmp;
}
void
fdinstall_remapped(struct thread *td, struct filedesc *fdp)
{
fdescfree(td);
td->td_proc->p_fd = fdp;
}
/*
* Copy a filedesc structure. A NULL pointer in returns a NULL reference,
* this is to ease callers, not catch errors.
*/
struct filedesc *
fdcopy(struct filedesc *fdp)
{
struct filedesc *newfdp;
struct filedescent *nfde, *ofde;
int i, lastfile;
MPASS(fdp != NULL);
newfdp = fdinit(fdp, true, &lastfile);
/* copy all passable descriptors (i.e. not kqueue) */
newfdp->fd_freefile = -1;
for (i = 0; i <= lastfile; ++i) {
ofde = &fdp->fd_ofiles[i];
if (ofde->fde_file == NULL ||
(ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0 ||
!fhold(ofde->fde_file)) {
if (newfdp->fd_freefile == -1)
newfdp->fd_freefile = i;
continue;
}
nfde = &newfdp->fd_ofiles[i];
*nfde = *ofde;
filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true);
fdused_init(newfdp, i);
}
if (newfdp->fd_freefile == -1)
newfdp->fd_freefile = i;
newfdp->fd_cmask = fdp->fd_cmask;
FILEDESC_SUNLOCK(fdp);
return (newfdp);
}
/*
* Copies a filedesc structure, while remapping all file descriptors
* stored inside using a translation table.
*
* File descriptors are copied over to the new file descriptor table,
* regardless of whether the close-on-exec flag is set.
*/
int
fdcopy_remapped(struct filedesc *fdp, const int *fds, size_t nfds,
struct filedesc **ret)
{
struct filedesc *newfdp;
struct filedescent *nfde, *ofde;
int error, i, lastfile;
MPASS(fdp != NULL);
newfdp = fdinit(fdp, true, &lastfile);
if (nfds > lastfile + 1) {
/* New table cannot be larger than the old one. */
error = E2BIG;
goto bad;
}
/* Copy all passable descriptors (i.e. not kqueue). */
newfdp->fd_freefile = nfds;
for (i = 0; i < nfds; ++i) {
if (fds[i] < 0 || fds[i] > lastfile) {
/* File descriptor out of bounds. */
error = EBADF;
goto bad;
}
ofde = &fdp->fd_ofiles[fds[i]];
if (ofde->fde_file == NULL) {
/* Unused file descriptor. */
error = EBADF;
goto bad;
}
if ((ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0) {
/* File descriptor cannot be passed. */
error = EINVAL;
goto bad;
}
if (!fhold(ofde->fde_file)) {
error = EBADF;
goto bad;
}
nfde = &newfdp->fd_ofiles[i];
*nfde = *ofde;
filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true);
fdused_init(newfdp, i);
}
newfdp->fd_cmask = fdp->fd_cmask;
FILEDESC_SUNLOCK(fdp);
*ret = newfdp;
return (0);
bad:
FILEDESC_SUNLOCK(fdp);
fdescfree_remapped(newfdp);
return (error);
}
/*
* Clear POSIX style locks. This is only used when fdp looses a reference (i.e.
* one of processes using it exits) and the table used to be shared.
*/
static void
fdclearlocks(struct thread *td)
{
struct filedesc *fdp;
struct filedesc_to_leader *fdtol;
struct flock lf;
struct file *fp;
struct proc *p;
struct vnode *vp;
int i, lastfile;
p = td->td_proc;
fdp = p->p_fd;
fdtol = p->p_fdtol;
MPASS(fdtol != NULL);
FILEDESC_XLOCK(fdp);
KASSERT(fdtol->fdl_refcount > 0,
("filedesc_to_refcount botch: fdl_refcount=%d",
fdtol->fdl_refcount));
if (fdtol->fdl_refcount == 1 &&
(p->p_leader->p_flag & P_ADVLOCK) != 0) {
lastfile = fdlastfile(fdp);
for (i = 0; i <= lastfile; i++) {
fp = fdp->fd_ofiles[i].fde_file;
if (fp == NULL || fp->f_type != DTYPE_VNODE ||
!fhold(fp))
continue;
FILEDESC_XUNLOCK(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)p->p_leader, F_UNLCK,
&lf, F_POSIX);
FILEDESC_XLOCK(fdp);
fdrop(fp, td);
}
}
retry:
if (fdtol->fdl_refcount == 1) {
if (fdp->fd_holdleaderscount > 0 &&
(p->p_leader->p_flag & P_ADVLOCK) != 0) {
/*
* close() or kern_dup() has cleared a reference
* in a shared file descriptor table.
*/
fdp->fd_holdleaderswakeup = 1;
sx_sleep(&fdp->fd_holdleaderscount,
FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0);
goto retry;
}
if (fdtol->fdl_holdcount > 0) {
/*
* Ensure that fdtol->fdl_leader remains
* valid in closef().
*/
fdtol->fdl_wakeup = 1;
sx_sleep(fdtol, FILEDESC_LOCK(fdp), 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;
p->p_fdtol = NULL;
FILEDESC_XUNLOCK(fdp);
if (fdtol != NULL)
free(fdtol, M_FILEDESC_TO_LEADER);
}
/*
* Release a filedesc structure.
*/
static void
fdescfree_fds(struct thread *td, struct filedesc *fdp, bool needclose)
{
struct filedesc0 *fdp0;
struct freetable *ft, *tft;
struct filedescent *fde;
struct file *fp;
int i, lastfile;
lastfile = fdlastfile_single(fdp);
for (i = 0; i <= lastfile; i++) {
fde = &fdp->fd_ofiles[i];
fp = fde->fde_file;
if (fp != NULL) {
fdefree_last(fde);
if (needclose)
(void) closef(fp, td);
else
fdrop(fp, td);
}
}
if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE))
free(fdp->fd_map, M_FILEDESC);
if (fdp->fd_nfiles > NDFILE)
free(fdp->fd_files, M_FILEDESC);
fdp0 = (struct filedesc0 *)fdp;
SLIST_FOREACH_SAFE(ft, &fdp0->fd_free, ft_next, tft)
free(ft->ft_table, M_FILEDESC);
fddrop(fdp);
}
void
fdescfree(struct thread *td)
{
struct proc *p;
struct filedesc *fdp;
struct pwd *pwd;
p = td->td_proc;
fdp = p->p_fd;
MPASS(fdp != NULL);
#ifdef RACCT
if (RACCT_ENABLED())
racct_set_unlocked(p, RACCT_NOFILE, 0);
#endif
if (p->p_fdtol != NULL)
fdclearlocks(td);
PROC_LOCK(p);
p->p_fd = NULL;
PROC_UNLOCK(p);
if (refcount_release(&fdp->fd_refcnt) == 0)
return;
FILEDESC_XLOCK(fdp);
pwd = FILEDESC_XLOCKED_LOAD_PWD(fdp);
pwd_set(fdp, NULL);
FILEDESC_XUNLOCK(fdp);
pwd_drop(pwd);
fdescfree_fds(td, fdp, 1);
}
void
fdescfree_remapped(struct filedesc *fdp)
{
pwd_drop(smr_serialized_load(&fdp->fd_pwd, true));
fdescfree_fds(curthread, fdp, 0);
}
/*
* 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 fdsetugidsafety calls this only for fd 0, 1 and 2, this check is
* sufficient. We also don't check for setugidness since we know we are.
*/
static bool
is_unsafe(struct file *fp)
{
struct vnode *vp;
if (fp->f_type != DTYPE_VNODE)
return (false);
vp = fp->f_vnode;
return ((vp->v_vflag & VV_PROCDEP) != 0);
}
/*
* Make this setguid thing safe, if at all possible.
*/
void
fdsetugidsafety(struct thread *td)
{
struct filedesc *fdp;
struct file *fp;
int i;
fdp = td->td_proc->p_fd;
KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
MPASS(fdp->fd_nfiles >= 3);
for (i = 0; i <= 2; i++) {
fp = fdp->fd_ofiles[i].fde_file;
if (fp != NULL && is_unsafe(fp)) {
FILEDESC_XLOCK(fdp);
knote_fdclose(td, i);
/*
* NULL-out descriptor prior to close to avoid
* a race while close blocks.
*/
fdfree(fdp, i);
FILEDESC_XUNLOCK(fdp);
(void) closef(fp, td);
}
}
}
/*
* If a specific file object occupies a specific file descriptor, close the
* file descriptor entry and drop a reference on the file object. This is a
* convenience function to handle a subsequent error in a function that calls
* falloc() that handles the race that another thread might have closed the
* file descriptor out from under the thread creating the file object.
*/
void
fdclose(struct thread *td, struct file *fp, int idx)
{
struct filedesc *fdp = td->td_proc->p_fd;
FILEDESC_XLOCK(fdp);
if (fdp->fd_ofiles[idx].fde_file == fp) {
fdfree(fdp, idx);
FILEDESC_XUNLOCK(fdp);
fdrop(fp, td);
} else
FILEDESC_XUNLOCK(fdp);
}
/*
* Close any files on exec?
*/
void
fdcloseexec(struct thread *td)
{
struct filedesc *fdp;
struct filedescent *fde;
struct file *fp;
int i, lastfile;
fdp = td->td_proc->p_fd;
KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
lastfile = fdlastfile_single(fdp);
for (i = 0; i <= lastfile; i++) {
fde = &fdp->fd_ofiles[i];
fp = fde->fde_file;
if (fp != NULL && (fp->f_type == DTYPE_MQUEUE ||
(fde->fde_flags & UF_EXCLOSE))) {
FILEDESC_XLOCK(fdp);
fdfree(fdp, i);
(void) closefp(fdp, i, fp, td, 0);
FILEDESC_UNLOCK_ASSERT(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(struct thread *td)
{
struct filedesc *fdp;
register_t save;
int i, error, devnull;
fdp = td->td_proc->p_fd;
KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
MPASS(fdp->fd_nfiles >= 3);
devnull = -1;
for (i = 0; i <= 2; i++) {
if (fdp->fd_ofiles[i].fde_file != NULL)
continue;
save = td->td_retval[0];
if (devnull != -1) {
error = kern_dup(td, FDDUP_FIXED, 0, devnull, i);
} else {
error = kern_openat(td, AT_FDCWD, "/dev/null",
UIO_SYSSPACE, O_RDWR, 0);
if (error == 0) {
devnull = td->td_retval[0];
KASSERT(devnull == i, ("we didn't get our fd"));
}
}
td->td_retval[0] = save;
if (error != 0)
return (error);
}
return (0);
}
/*
* 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(struct file *fp, struct thread *td)
{
struct vnode *vp;
struct flock lf;
struct filedesc_to_leader *fdtol;
struct filedesc *fdp;
/*
* 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, and the thread pointer
* will be NULL. Callers should be careful only to pass a
* NULL thread pointer when there really is no owning
* context that might have locks, or the locks will be
* leaked.
*/
if (fp->f_type == DTYPE_VNODE && td != NULL) {
vp = fp->f_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;
(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_XLOCK(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_XUNLOCK(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_XLOCK(fdp);
fdtol->fdl_holdcount--;
if (fdtol->fdl_holdcount == 0 &&
fdtol->fdl_wakeup != 0) {
fdtol->fdl_wakeup = 0;
wakeup(fdtol);
}
}
FILEDESC_XUNLOCK(fdp);
}
}
return (fdrop(fp, td));
}
/*
* Initialize the file pointer with the specified properties.
*
* The ops are set with release semantics to be certain that the flags, type,
* and data are visible when ops is. This is to prevent ops methods from being
* called with bad data.
*/
void
finit(struct file *fp, u_int flag, short type, void *data, struct fileops *ops)
{
fp->f_data = data;
fp->f_flag = flag;
fp->f_type = type;
atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops);
}
void
finit_vnode(struct file *fp, u_int flag, void *data, struct fileops *ops)
{
fp->f_seqcount[UIO_READ] = 1;
fp->f_seqcount[UIO_WRITE] = 1;
finit(fp, (flag & FMASK) | (fp->f_flag & FHASLOCK), DTYPE_VNODE,
data, ops);
}
int
fget_cap_locked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp, struct filecaps *havecapsp)
{
struct filedescent *fde;
int error;
FILEDESC_LOCK_ASSERT(fdp);
fde = fdeget_locked(fdp, fd);
if (fde == NULL) {
error = EBADF;
goto out;
}
#ifdef CAPABILITIES
error = cap_check(cap_rights_fde_inline(fde), needrightsp);
if (error != 0)
goto out;
#endif
if (havecapsp != NULL)
filecaps_copy(&fde->fde_caps, havecapsp, true);
*fpp = fde->fde_file;
error = 0;
out:
return (error);
}
int
fget_cap(struct thread *td, int fd, cap_rights_t *needrightsp,
struct file **fpp, struct filecaps *havecapsp)
{
struct filedesc *fdp = td->td_proc->p_fd;
int error;
#ifndef CAPABILITIES
error = fget_unlocked(fdp, fd, needrightsp, fpp);
if (havecapsp != NULL && error == 0)
filecaps_fill(havecapsp);
#else
struct file *fp;
seqc_t seq;
*fpp = NULL;
for (;;) {
error = fget_unlocked_seq(fdp, fd, needrightsp, &fp, &seq);
if (error != 0)
return (error);
if (havecapsp != NULL) {
if (!filecaps_copy(&fdp->fd_ofiles[fd].fde_caps,
havecapsp, false)) {
fdrop(fp, td);
goto get_locked;
}
}
if (!fd_modified(fdp, fd, seq))
break;
fdrop(fp, td);
}
*fpp = fp;
return (0);
get_locked:
FILEDESC_SLOCK(fdp);
error = fget_cap_locked(fdp, fd, needrightsp, fpp, havecapsp);
if (error == 0 && !fhold(*fpp))
error = EBADF;
FILEDESC_SUNLOCK(fdp);
#endif
return (error);
}
#ifdef CAPABILITIES
int
fgetvp_lookup_smr(int fd, struct nameidata *ndp, struct vnode **vpp, bool *fsearch)
{
const struct filedescent *fde;
const struct fdescenttbl *fdt;
struct filedesc *fdp;
struct file *fp;
struct vnode *vp;
const cap_rights_t *haverights;
cap_rights_t rights;
seqc_t seq;
VFS_SMR_ASSERT_ENTERED();
rights = *ndp->ni_rightsneeded;
cap_rights_set_one(&rights, CAP_LOOKUP);
fdp = curproc->p_fd;
fdt = fdp->fd_files;
if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
return (EBADF);
seq = seqc_read_any(fd_seqc(fdt, fd));
if (__predict_false(seqc_in_modify(seq)))
return (EAGAIN);
fde = &fdt->fdt_ofiles[fd];
haverights = cap_rights_fde_inline(fde);
fp = fde->fde_file;
if (__predict_false(fp == NULL))
return (EAGAIN);
if (__predict_false(cap_check_inline_transient(haverights, &rights)))
return (EAGAIN);
*fsearch = ((fp->f_flag & FSEARCH) != 0);
vp = fp->f_vnode;
if (__predict_false(vp == NULL || vp->v_type != VDIR)) {
return (EAGAIN);
}
if (!filecaps_copy(&fde->fde_caps, &ndp->ni_filecaps, false)) {
return (EAGAIN);
}
/*
* Use an acquire barrier to force re-reading of fdt so it is
* refreshed for verification.
*/
atomic_thread_fence_acq();
fdt = fdp->fd_files;
if (__predict_false(!seqc_consistent_nomb(fd_seqc(fdt, fd), seq)))
return (EAGAIN);
/*
* If file descriptor doesn't have all rights,
* all lookups relative to it must also be
* strictly relative.
*
* Not yet supported by fast path.
*/
CAP_ALL(&rights);
if (!cap_rights_contains(&ndp->ni_filecaps.fc_rights, &rights) ||
ndp->ni_filecaps.fc_fcntls != CAP_FCNTL_ALL ||
ndp->ni_filecaps.fc_nioctls != -1) {
#ifdef notyet
ndp->ni_lcf |= NI_LCF_STRICTRELATIVE;
#else
return (EAGAIN);
#endif
}
*vpp = vp;
return (0);
}
#else
int
fgetvp_lookup_smr(int fd, struct nameidata *ndp, struct vnode **vpp, bool *fsearch)
{
const struct fdescenttbl *fdt;
struct filedesc *fdp;
struct file *fp;
struct vnode *vp;
VFS_SMR_ASSERT_ENTERED();
fdp = curproc->p_fd;
fdt = fdp->fd_files;
if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
return (EBADF);
fp = fdt->fdt_ofiles[fd].fde_file;
if (__predict_false(fp == NULL))
return (EAGAIN);
*fsearch = ((fp->f_flag & FSEARCH) != 0);
vp = fp->f_vnode;
if (__predict_false(vp == NULL || vp->v_type != VDIR)) {
return (EAGAIN);
}
/*
* Use an acquire barrier to force re-reading of fdt so it is
* refreshed for verification.
*/
atomic_thread_fence_acq();
fdt = fdp->fd_files;
if (__predict_false(fp != fdt->fdt_ofiles[fd].fde_file))
return (EAGAIN);
filecaps_fill(&ndp->ni_filecaps);
*vpp = vp;
return (0);
}
#endif
int
fget_unlocked_seq(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp, seqc_t *seqp)
{
#ifdef CAPABILITIES
const struct filedescent *fde;
#endif
const struct fdescenttbl *fdt;
struct file *fp;
#ifdef CAPABILITIES
seqc_t seq;
cap_rights_t haverights;
int error;
#endif
fdt = fdp->fd_files;
if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
return (EBADF);
/*
* Fetch the descriptor locklessly. We avoid fdrop() races by
* never raising a refcount above 0. To accomplish this we have
* to use a cmpset loop rather than an atomic_add. The descriptor
* must be re-verified once we acquire a reference to be certain
* that the identity is still correct and we did not lose a race
* due to preemption.
*/
for (;;) {
#ifdef CAPABILITIES
seq = seqc_read(fd_seqc(fdt, fd));
fde = &fdt->fdt_ofiles[fd];
haverights = *cap_rights_fde_inline(fde);
fp = fde->fde_file;
if (!seqc_consistent(fd_seqc(fdt, fd), seq))
continue;
#else
fp = fdt->fdt_ofiles[fd].fde_file;
#endif
if (fp == NULL)
return (EBADF);
#ifdef CAPABILITIES
error = cap_check_inline(&haverights, needrightsp);
if (error != 0)
return (error);
#endif
if (__predict_false(!refcount_acquire_if_not_zero(&fp->f_count))) {
/*
* The count was found either saturated or zero.
* This re-read is not any more racy than using the
* return value from fcmpset.
*/
if (refcount_load(&fp->f_count) != 0)
return (EBADF);
/*
* Force a reload. Other thread could reallocate the
* table before this fd was closed, so it is possible
* that there is a stale fp pointer in cached version.
*/
fdt = atomic_load_ptr(&fdp->fd_files);
continue;
}
/*
* Use an acquire barrier to force re-reading of fdt so it is
* refreshed for verification.
*/
atomic_thread_fence_acq();
fdt = fdp->fd_files;
#ifdef CAPABILITIES
if (seqc_consistent_nomb(fd_seqc(fdt, fd), seq))
#else
if (fp == fdt->fdt_ofiles[fd].fde_file)
#endif
break;
fdrop(fp, curthread);
}
*fpp = fp;
if (seqp != NULL) {
#ifdef CAPABILITIES
*seqp = seq;
#endif
}
return (0);
}
/*
* See the comments in fget_unlocked_seq for an explanation of how this works.
*
* This is a simplified variant which bails out to the aforementioned routine
* if anything goes wrong. In practice this only happens when userspace is
* racing with itself.
*/
int
fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp)
{
#ifdef CAPABILITIES
const struct filedescent *fde;
#endif
const struct fdescenttbl *fdt;
struct file *fp;
#ifdef CAPABILITIES
seqc_t seq;
const cap_rights_t *haverights;
#endif
fdt = fdp->fd_files;
if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
return (EBADF);
#ifdef CAPABILITIES
seq = seqc_read_any(fd_seqc(fdt, fd));
if (__predict_false(seqc_in_modify(seq)))
goto out_fallback;
fde = &fdt->fdt_ofiles[fd];
haverights = cap_rights_fde_inline(fde);
fp = fde->fde_file;
#else
fp = fdt->fdt_ofiles[fd].fde_file;
#endif
if (__predict_false(fp == NULL))
goto out_fallback;
#ifdef CAPABILITIES
if (__predict_false(cap_check_inline_transient(haverights, needrightsp)))
goto out_fallback;
#endif
if (__predict_false(!refcount_acquire_if_not_zero(&fp->f_count)))
goto out_fallback;
/*
* Use an acquire barrier to force re-reading of fdt so it is
* refreshed for verification.
*/
atomic_thread_fence_acq();
fdt = fdp->fd_files;
#ifdef CAPABILITIES
if (__predict_false(!seqc_consistent_nomb(fd_seqc(fdt, fd), seq)))
#else
if (__predict_false(fp != fdt->fdt_ofiles[fd].fde_file))
#endif
goto out_fdrop;
*fpp = fp;
return (0);
out_fdrop:
fdrop(fp, curthread);
out_fallback:
return (fget_unlocked_seq(fdp, fd, needrightsp, fpp, NULL));
}
/*
* Extract the file pointer associated with the specified descriptor for the
* current user process.
*
* If the descriptor doesn't exist or doesn't match 'flags', EBADF is
* returned.
*
* File's rights will be checked against the capability rights mask.
*
* If an error occurred the non-zero error is returned and *fpp is set to
* NULL. Otherwise *fpp is held and set and zero is returned. Caller is
* responsible for fdrop().
*/
static __inline int
_fget(struct thread *td, int fd, struct file **fpp, int flags,
cap_rights_t *needrightsp)
{
struct filedesc *fdp;
struct file *fp;
int error;
*fpp = NULL;
fdp = td->td_proc->p_fd;
error = fget_unlocked(fdp, fd, needrightsp, &fp);
if (__predict_false(error != 0))
return (error);
if (__predict_false(fp->f_ops == &badfileops)) {
fdrop(fp, td);
return (EBADF);
}
/*
* FREAD and FWRITE failure return EBADF as per POSIX.
*/
error = 0;
switch (flags) {
case FREAD:
case FWRITE:
if ((fp->f_flag & flags) == 0)
error = EBADF;
break;
case FEXEC:
if ((fp->f_flag & (FREAD | FEXEC)) == 0 ||
((fp->f_flag & FWRITE) != 0))
error = EBADF;
break;
case 0:
break;
default:
KASSERT(0, ("wrong flags"));
}
if (error != 0) {
fdrop(fp, td);
return (error);
}
*fpp = fp;
return (0);
}
int
fget(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp)
{
return (_fget(td, fd, fpp, 0, rightsp));
}
int
fget_mmap(struct thread *td, int fd, cap_rights_t *rightsp, vm_prot_t *maxprotp,
struct file **fpp)
{
int error;
#ifndef CAPABILITIES
error = _fget(td, fd, fpp, 0, rightsp);
if (maxprotp != NULL)
*maxprotp = VM_PROT_ALL;
return (error);
#else
cap_rights_t fdrights;
struct filedesc *fdp;
struct file *fp;
seqc_t seq;
*fpp = NULL;
fdp = td->td_proc->p_fd;
MPASS(cap_rights_is_set(rightsp, CAP_MMAP));
for (;;) {
error = fget_unlocked_seq(fdp, fd, rightsp, &fp, &seq);
if (__predict_false(error != 0))
return (error);
if (__predict_false(fp->f_ops == &badfileops)) {
fdrop(fp, td);
return (EBADF);
}
if (maxprotp != NULL)
fdrights = *cap_rights(fdp, fd);
if (!fd_modified(fdp, fd, seq))
break;
fdrop(fp, td);
}
/*
* If requested, convert capability rights to access flags.
*/
if (maxprotp != NULL)
*maxprotp = cap_rights_to_vmprot(&fdrights);
*fpp = fp;
return (0);
#endif
}
int
fget_read(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp)
{
return (_fget(td, fd, fpp, FREAD, rightsp));
}
int
fget_write(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp)
{
return (_fget(td, fd, fpp, FWRITE, rightsp));
}
int
fget_fcntl(struct thread *td, int fd, cap_rights_t *rightsp, int needfcntl,
struct file **fpp)
{
struct filedesc *fdp = td->td_proc->p_fd;
#ifndef CAPABILITIES
return (fget_unlocked(fdp, fd, rightsp, fpp));
#else
struct file *fp;
int error;
seqc_t seq;
*fpp = NULL;
MPASS(cap_rights_is_set(rightsp, CAP_FCNTL));
for (;;) {
error = fget_unlocked_seq(fdp, fd, rightsp, &fp, &seq);
if (error != 0)
return (error);
error = cap_fcntl_check(fdp, fd, needfcntl);
if (!fd_modified(fdp, fd, seq))
break;
fdrop(fp, td);
}
if (error != 0) {
fdrop(fp, td);
return (error);
}
*fpp = fp;
return (0);
#endif
}
/*
* 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. The returned vnode will be vref()'d.
*
* XXX: what about the unused flags ?
*/
static __inline int
_fgetvp(struct thread *td, int fd, int flags, cap_rights_t *needrightsp,
struct vnode **vpp)
{
struct file *fp;
int error;
*vpp = NULL;
error = _fget(td, fd, &fp, flags, needrightsp);
if (error != 0)
return (error);
if (fp->f_vnode == NULL) {
error = EINVAL;
} else {
*vpp = fp->f_vnode;
vrefact(*vpp);
}
fdrop(fp, td);
return (error);
}
int
fgetvp(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp)
{
return (_fgetvp(td, fd, 0, rightsp, vpp));
}
int
fgetvp_rights(struct thread *td, int fd, cap_rights_t *needrightsp,
struct filecaps *havecaps, struct vnode **vpp)
{
struct filecaps caps;
struct file *fp;
int error;
error = fget_cap(td, fd, needrightsp, &fp, &caps);
if (error != 0)
return (error);
if (fp->f_ops == &badfileops) {
error = EBADF;
goto out;
}
if (fp->f_vnode == NULL) {
error = EINVAL;
goto out;
}
*havecaps = caps;
*vpp = fp->f_vnode;
vrefact(*vpp);
fdrop(fp, td);
return (0);
out:
filecaps_free(&caps);
fdrop(fp, td);
return (error);
}
int
fgetvp_read(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp)
{
return (_fgetvp(td, fd, FREAD, rightsp, vpp));
}
int
fgetvp_exec(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp)
{
return (_fgetvp(td, fd, FEXEC, rightsp, vpp));
}
#ifdef notyet
int
fgetvp_write(struct thread *td, int fd, cap_rights_t *rightsp,
struct vnode **vpp)
{
return (_fgetvp(td, fd, FWRITE, rightsp, vpp));
}
#endif
/*
* Handle the last reference to a file being closed.
*
* Without the noinline attribute clang keeps inlining the func thorough this
* file when fdrop is used.
*/
int __noinline
_fdrop(struct file *fp, struct thread *td)
{
int error;
#ifdef INVARIANTS
int count;
count = refcount_load(&fp->f_count);
if (count != 0)
panic("fdrop: fp %p count %d", fp, count);
#endif
error = fo_close(fp, td);
atomic_subtract_int(&openfiles, 1);
crfree(fp->f_cred);
free(fp->f_advice, M_FADVISE);
uma_zfree(file_zone, 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
sys_flock(struct thread *td, struct flock_args *uap)
{
struct file *fp;
struct vnode *vp;
struct flock lf;
int error;
error = fget(td, uap->fd, &cap_flock_rights, &fp);
if (error != 0)
return (error);
if (fp->f_type != DTYPE_VNODE) {
fdrop(fp, td);
return (EOPNOTSUPP);
}
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;
atomic_clear_int(&fp->f_flag, FHASLOCK);
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;
}
atomic_set_int(&fp->f_flag, FHASLOCK);
error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf,
(uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT);
done2:
fdrop(fp, td);
return (error);
}
/*
* Duplicate the specified descriptor to a free descriptor.
*/
int
dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode,
int openerror, int *indxp)
{
struct filedescent *newfde, *oldfde;
struct file *fp;
u_long *ioctls;
int error, indx;
KASSERT(openerror == ENODEV || openerror == ENXIO,
("unexpected error %d in %s", openerror, __func__));
/*
* 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_XLOCK(fdp);
if ((fp = fget_locked(fdp, dfd)) == NULL) {
FILEDESC_XUNLOCK(fdp);
return (EBADF);
}
error = fdalloc(td, 0, &indx);
if (error != 0) {
FILEDESC_XUNLOCK(fdp);
return (error);
}
/*
* 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.
*/
switch (openerror) {
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)) | fp->f_flag) != fp->f_flag) {
fdunused(fdp, indx);
FILEDESC_XUNLOCK(fdp);
return (EACCES);
}
if (!fhold(fp)) {
fdunused(fdp, indx);
FILEDESC_XUNLOCK(fdp);
return (EBADF);
}
newfde = &fdp->fd_ofiles[indx];
oldfde = &fdp->fd_ofiles[dfd];
ioctls = filecaps_copy_prep(&oldfde->fde_caps);
#ifdef CAPABILITIES
seqc_write_begin(&newfde->fde_seqc);
#endif
memcpy(newfde, oldfde, fde_change_size);
filecaps_copy_finish(&oldfde->fde_caps, &newfde->fde_caps,
ioctls);
#ifdef CAPABILITIES
seqc_write_end(&newfde->fde_seqc);
#endif
break;
case ENXIO:
/*
* Steal away the file pointer from dfd and stuff it into indx.
*/
newfde = &fdp->fd_ofiles[indx];
oldfde = &fdp->fd_ofiles[dfd];
#ifdef CAPABILITIES
seqc_write_begin(&newfde->fde_seqc);
#endif
memcpy(newfde, oldfde, fde_change_size);
oldfde->fde_file = NULL;
fdunused(fdp, dfd);
#ifdef CAPABILITIES
seqc_write_end(&newfde->fde_seqc);
#endif
break;
}
FILEDESC_XUNLOCK(fdp);
*indxp = indx;
return (0);
}
/*
* This sysctl determines if we will allow a process to chroot(2) if it
* has a directory open:
* 0: disallowed for all processes.
* 1: allowed for processes that were not already chroot(2)'ed.
* 2: allowed for all processes.
*/
static int chroot_allow_open_directories = 1;
SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW,
&chroot_allow_open_directories, 0,
"Allow a process to chroot(2) if it has a directory open");
/*
* Helper function for raised chroot(2) security function: Refuse if
* any filedescriptors are open directories.
*/
static int
chroot_refuse_vdir_fds(struct filedesc *fdp)
{
struct vnode *vp;
struct file *fp;
int fd, lastfile;
FILEDESC_LOCK_ASSERT(fdp);
lastfile = fdlastfile(fdp);
for (fd = 0; fd <= lastfile; fd++) {
fp = fget_locked(fdp, fd);
if (fp == NULL)
continue;
if (fp->f_type == DTYPE_VNODE) {
vp = fp->f_vnode;
if (vp->v_type == VDIR)
return (EPERM);
}
}
return (0);
}
static void
pwd_fill(struct pwd *oldpwd, struct pwd *newpwd)
{
if (newpwd->pwd_cdir == NULL && oldpwd->pwd_cdir != NULL) {
vrefact(oldpwd->pwd_cdir);
newpwd->pwd_cdir = oldpwd->pwd_cdir;
}
if (newpwd->pwd_rdir == NULL && oldpwd->pwd_rdir != NULL) {
vrefact(oldpwd->pwd_rdir);
newpwd->pwd_rdir = oldpwd->pwd_rdir;
}
if (newpwd->pwd_jdir == NULL && oldpwd->pwd_jdir != NULL) {
vrefact(oldpwd->pwd_jdir);
newpwd->pwd_jdir = oldpwd->pwd_jdir;
}
}
struct pwd *
pwd_hold_filedesc(struct filedesc *fdp)
{
struct pwd *pwd;
FILEDESC_LOCK_ASSERT(fdp);
pwd = FILEDESC_LOCKED_LOAD_PWD(fdp);
if (pwd != NULL)
refcount_acquire(&pwd->pwd_refcount);
return (pwd);
}
bool
pwd_hold_smr(struct pwd *pwd)
{
MPASS(pwd != NULL);
if (__predict_true(refcount_acquire_if_not_zero(&pwd->pwd_refcount))) {
return (true);
}
return (false);
}
struct pwd *
pwd_hold(struct thread *td)
{
struct filedesc *fdp;
struct pwd *pwd;
fdp = td->td_proc->p_fd;
vfs_smr_enter();
pwd = vfs_smr_entered_load(&fdp->fd_pwd);
if (pwd_hold_smr(pwd)) {
vfs_smr_exit();
return (pwd);
}
vfs_smr_exit();
FILEDESC_SLOCK(fdp);
pwd = pwd_hold_filedesc(fdp);
MPASS(pwd != NULL);
FILEDESC_SUNLOCK(fdp);
return (pwd);
}
struct pwd *
pwd_get_smr(void)
{
struct pwd *pwd;
pwd = vfs_smr_entered_load(&curproc->p_fd->fd_pwd);
MPASS(pwd != NULL);
return (pwd);
}
static struct pwd *
pwd_alloc(void)
{
struct pwd *pwd;
pwd = uma_zalloc_smr(pwd_zone, M_WAITOK);
bzero(pwd, sizeof(*pwd));
refcount_init(&pwd->pwd_refcount, 1);
return (pwd);
}
void
pwd_drop(struct pwd *pwd)
{
if (!refcount_release(&pwd->pwd_refcount))
return;
if (pwd->pwd_cdir != NULL)
vrele(pwd->pwd_cdir);
if (pwd->pwd_rdir != NULL)
vrele(pwd->pwd_rdir);
if (pwd->pwd_jdir != NULL)
vrele(pwd->pwd_jdir);
uma_zfree_smr(pwd_zone, pwd);
}
/*
* Common routine for kern_chroot() and jail_attach(). The caller is
* responsible for invoking priv_check() and mac_vnode_check_chroot() to
* authorize this operation.
*/
int
pwd_chroot(struct thread *td, struct vnode *vp)
{
struct filedesc *fdp;
struct pwd *newpwd, *oldpwd;
int error;
fdp = td->td_proc->p_fd;
newpwd = pwd_alloc();
FILEDESC_XLOCK(fdp);
oldpwd = FILEDESC_XLOCKED_LOAD_PWD(fdp);
if (chroot_allow_open_directories == 0 ||
(chroot_allow_open_directories == 1 &&
oldpwd->pwd_rdir != rootvnode)) {
error = chroot_refuse_vdir_fds(fdp);
if (error != 0) {
FILEDESC_XUNLOCK(fdp);
pwd_drop(newpwd);
return (error);
}
}
vrefact(vp);
newpwd->pwd_rdir = vp;
if (oldpwd->pwd_jdir == NULL) {
vrefact(vp);
newpwd->pwd_jdir = vp;
}
pwd_fill(oldpwd, newpwd);
pwd_set(fdp, newpwd);
FILEDESC_XUNLOCK(fdp);
pwd_drop(oldpwd);
return (0);
}
void
pwd_chdir(struct thread *td, struct vnode *vp)
{
struct filedesc *fdp;
struct pwd *newpwd, *oldpwd;
VNPASS(vp->v_usecount > 0, vp);
newpwd = pwd_alloc();
fdp = td->td_proc->p_fd;
FILEDESC_XLOCK(fdp);
oldpwd = FILEDESC_XLOCKED_LOAD_PWD(fdp);
newpwd->pwd_cdir = vp;
pwd_fill(oldpwd, newpwd);
pwd_set(fdp, newpwd);
FILEDESC_XUNLOCK(fdp);
pwd_drop(oldpwd);
}
void
pwd_ensure_dirs(void)
{
struct filedesc *fdp;
struct pwd *oldpwd, *newpwd;
fdp = curproc->p_fd;
FILEDESC_XLOCK(fdp);
oldpwd = FILEDESC_XLOCKED_LOAD_PWD(fdp);
if (oldpwd->pwd_cdir != NULL && oldpwd->pwd_rdir != NULL) {
FILEDESC_XUNLOCK(fdp);
return;
}
FILEDESC_XUNLOCK(fdp);
newpwd = pwd_alloc();
FILEDESC_XLOCK(fdp);
oldpwd = FILEDESC_XLOCKED_LOAD_PWD(fdp);
pwd_fill(oldpwd, newpwd);
if (newpwd->pwd_cdir == NULL) {
vrefact(rootvnode);
newpwd->pwd_cdir = rootvnode;
}
if (newpwd->pwd_rdir == NULL) {
vrefact(rootvnode);
newpwd->pwd_rdir = rootvnode;
}
pwd_set(fdp, newpwd);
FILEDESC_XUNLOCK(fdp);
pwd_drop(oldpwd);
}
void
pwd_set_rootvnode(void)
{
struct filedesc *fdp;
struct pwd *oldpwd, *newpwd;
fdp = curproc->p_fd;
newpwd = pwd_alloc();
FILEDESC_XLOCK(fdp);
oldpwd = FILEDESC_XLOCKED_LOAD_PWD(fdp);
vrefact(rootvnode);
newpwd->pwd_cdir = rootvnode;
vrefact(rootvnode);
newpwd->pwd_rdir = rootvnode;
pwd_fill(oldpwd, newpwd);
pwd_set(fdp, newpwd);
FILEDESC_XUNLOCK(fdp);
pwd_drop(oldpwd);
}
/*
* Scan all active processes and prisons to see if any of them have a current
* or root directory of `olddp'. If so, replace them with the new mount point.
*/
void
mountcheckdirs(struct vnode *olddp, struct vnode *newdp)
{
struct filedesc *fdp;
struct pwd *newpwd, *oldpwd;
struct prison *pr;
struct proc *p;
int nrele;
if (vrefcnt(olddp) == 1)
return;
nrele = 0;
newpwd = pwd_alloc();
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
fdp = fdhold(p);
PROC_UNLOCK(p);
if (fdp == NULL)
continue;
FILEDESC_XLOCK(fdp);
oldpwd = FILEDESC_XLOCKED_LOAD_PWD(fdp);
if (oldpwd == NULL ||
(oldpwd->pwd_cdir != olddp &&
oldpwd->pwd_rdir != olddp &&
oldpwd->pwd_jdir != olddp)) {
FILEDESC_XUNLOCK(fdp);
fddrop(fdp);
continue;
}
if (oldpwd->pwd_cdir == olddp) {
vrefact(newdp);
newpwd->pwd_cdir = newdp;
}
if (oldpwd->pwd_rdir == olddp) {
vrefact(newdp);
newpwd->pwd_rdir = newdp;
}
if (oldpwd->pwd_jdir == olddp) {
vrefact(newdp);
newpwd->pwd_jdir = newdp;
}
pwd_fill(oldpwd, newpwd);
pwd_set(fdp, newpwd);
FILEDESC_XUNLOCK(fdp);
pwd_drop(oldpwd);
fddrop(fdp);
newpwd = pwd_alloc();
}
sx_sunlock(&allproc_lock);
pwd_drop(newpwd);
if (rootvnode == olddp) {
vrefact(newdp);
rootvnode = newdp;
nrele++;
}
mtx_lock(&prison0.pr_mtx);
if (prison0.pr_root == olddp) {
vrefact(newdp);
prison0.pr_root = newdp;
nrele++;
}
mtx_unlock(&prison0.pr_mtx);
sx_slock(&allprison_lock);
TAILQ_FOREACH(pr, &allprison, pr_list) {
mtx_lock(&pr->pr_mtx);
if (pr->pr_root == olddp) {
vrefact(newdp);
pr->pr_root = newdp;
nrele++;
}
mtx_unlock(&pr->pr_mtx);
}
sx_sunlock(&allprison_lock);
while (nrele--)
vrele(olddp);
}
struct filedesc_to_leader *
filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader)
{
struct filedesc_to_leader *fdtol;
fdtol = malloc(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_XLOCK(fdp);
fdtol->fdl_next = old->fdl_next;
fdtol->fdl_prev = old;
old->fdl_next = fdtol;
fdtol->fdl_next->fdl_prev = fdtol;
FILEDESC_XUNLOCK(fdp);
} else {
fdtol->fdl_next = fdtol;
fdtol->fdl_prev = fdtol;
}
return (fdtol);
}
static int
sysctl_kern_proc_nfds(SYSCTL_HANDLER_ARGS)
{
NDSLOTTYPE *map;
struct filedesc *fdp;
int count, off, minoff;
if (*(int *)arg1 != 0)
return (EINVAL);
fdp = curproc->p_fd;
count = 0;
FILEDESC_SLOCK(fdp);
map = fdp->fd_map;
off = NDSLOT(fdp->fd_nfiles - 1);
for (minoff = NDSLOT(0); off >= minoff; --off)
count += bitcountl(map[off]);
FILEDESC_SUNLOCK(fdp);
return (SYSCTL_OUT(req, &count, sizeof(count)));
}
static SYSCTL_NODE(_kern_proc, KERN_PROC_NFDS, nfds,
CTLFLAG_RD|CTLFLAG_CAPRD|CTLFLAG_MPSAFE, sysctl_kern_proc_nfds,
"Number of open file descriptors");
/*
* Get file structures globally.
*/
static int
sysctl_kern_file(SYSCTL_HANDLER_ARGS)
{
struct xfile xf;
struct filedesc *fdp;
struct file *fp;
struct proc *p;
int error, n, lastfile;
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
if (req->oldptr == NULL) {
n = 0;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
PROC_UNLOCK(p);
continue;
}
fdp = fdhold(p);
PROC_UNLOCK(p);
if (fdp == NULL)
continue;
/* overestimates sparse tables. */
n += fdp->fd_nfiles;
fddrop(fdp);
}
sx_sunlock(&allproc_lock);
return (SYSCTL_OUT(req, 0, n * sizeof(xf)));
}
error = 0;
bzero(&xf, sizeof(xf));
xf.xf_size = sizeof(xf);
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
PROC_UNLOCK(p);
continue;
}
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;
fdp = fdhold(p);
PROC_UNLOCK(p);
if (fdp == NULL)
continue;
FILEDESC_SLOCK(fdp);
lastfile = fdlastfile(fdp);
for (n = 0; fdp->fd_refcnt > 0 && n <= lastfile; ++n) {
if ((fp = fdp->fd_ofiles[n].fde_file) == NULL)
continue;
xf.xf_fd = n;
xf.xf_file = (uintptr_t)fp;
xf.xf_data = (uintptr_t)fp->f_data;
xf.xf_vnode = (uintptr_t)fp->f_vnode;
xf.xf_type = (uintptr_t)fp->f_type;
xf.xf_count = refcount_load(&fp->f_count);
xf.xf_msgcount = 0;
xf.xf_offset = foffset_get(fp);
xf.xf_flag = fp->f_flag;
error = SYSCTL_OUT(req, &xf, sizeof(xf));
if (error)
break;
}
FILEDESC_SUNLOCK(fdp);
fddrop(fdp);
if (error)
break;
}
sx_sunlock(&allproc_lock);
return (error);
}
SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
0, 0, sysctl_kern_file, "S,xfile", "Entire file table");
#ifdef KINFO_FILE_SIZE
CTASSERT(sizeof(struct kinfo_file) == KINFO_FILE_SIZE);
#endif
static int
xlate_fflags(int fflags)
{
static const struct {
int fflag;
int kf_fflag;
} fflags_table[] = {
{ FAPPEND, KF_FLAG_APPEND },
{ FASYNC, KF_FLAG_ASYNC },
{ FFSYNC, KF_FLAG_FSYNC },
{ FHASLOCK, KF_FLAG_HASLOCK },
{ FNONBLOCK, KF_FLAG_NONBLOCK },
{ FREAD, KF_FLAG_READ },
{ FWRITE, KF_FLAG_WRITE },
{ O_CREAT, KF_FLAG_CREAT },
{ O_DIRECT, KF_FLAG_DIRECT },
{ O_EXCL, KF_FLAG_EXCL },
{ O_EXEC, KF_FLAG_EXEC },
{ O_EXLOCK, KF_FLAG_EXLOCK },
{ O_NOFOLLOW, KF_FLAG_NOFOLLOW },
{ O_SHLOCK, KF_FLAG_SHLOCK },
{ O_TRUNC, KF_FLAG_TRUNC }
};
unsigned int i;
int kflags;
kflags = 0;
for (i = 0; i < nitems(fflags_table); i++)
if (fflags & fflags_table[i].fflag)
kflags |= fflags_table[i].kf_fflag;
return (kflags);
}
/* Trim unused data from kf_path by truncating the structure size. */
void
pack_kinfo(struct kinfo_file *kif)
{
kif->kf_structsize = offsetof(struct kinfo_file, kf_path) +
strlen(kif->kf_path) + 1;
kif->kf_structsize = roundup(kif->kf_structsize, sizeof(uint64_t));
}
static void
export_file_to_kinfo(struct file *fp, int fd, cap_rights_t *rightsp,
struct kinfo_file *kif, struct filedesc *fdp, int flags)
{
int error;
bzero(kif, sizeof(*kif));
/* Set a default type to allow for empty fill_kinfo() methods. */
kif->kf_type = KF_TYPE_UNKNOWN;
kif->kf_flags = xlate_fflags(fp->f_flag);
if (rightsp != NULL)
kif->kf_cap_rights = *rightsp;
else
cap_rights_init_zero(&kif->kf_cap_rights);
kif->kf_fd = fd;
kif->kf_ref_count = refcount_load(&fp->f_count);
kif->kf_offset = foffset_get(fp);
/*
* This may drop the filedesc lock, so the 'fp' cannot be
* accessed after this call.
*/
error = fo_fill_kinfo(fp, kif, fdp);
if (error == 0)
kif->kf_status |= KF_ATTR_VALID;
if ((flags & KERN_FILEDESC_PACK_KINFO) != 0)
pack_kinfo(kif);
else
kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t));
}
static void
export_vnode_to_kinfo(struct vnode *vp, int fd, int fflags,
struct kinfo_file *kif, int flags)
{
int error;
bzero(kif, sizeof(*kif));
kif->kf_type = KF_TYPE_VNODE;
error = vn_fill_kinfo_vnode(vp, kif);
if (error == 0)
kif->kf_status |= KF_ATTR_VALID;
kif->kf_flags = xlate_fflags(fflags);
cap_rights_init_zero(&kif->kf_cap_rights);
kif->kf_fd = fd;
kif->kf_ref_count = -1;
kif->kf_offset = -1;
if ((flags & KERN_FILEDESC_PACK_KINFO) != 0)
pack_kinfo(kif);
else
kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t));
vrele(vp);
}
struct export_fd_buf {
struct filedesc *fdp;
struct sbuf *sb;
ssize_t remainder;
struct kinfo_file kif;
int flags;
};
static int
export_kinfo_to_sb(struct export_fd_buf *efbuf)
{
struct kinfo_file *kif;
kif = &efbuf->kif;
if (efbuf->remainder != -1) {
if (efbuf->remainder < kif->kf_structsize) {
/* Terminate export. */
efbuf->remainder = 0;
return (0);
}
efbuf->remainder -= kif->kf_structsize;
}
return (sbuf_bcat(efbuf->sb, kif, kif->kf_structsize) == 0 ? 0 : ENOMEM);
}
static int
export_file_to_sb(struct file *fp, int fd, cap_rights_t *rightsp,
struct export_fd_buf *efbuf)
{
int error;
if (efbuf->remainder == 0)
return (0);
export_file_to_kinfo(fp, fd, rightsp, &efbuf->kif, efbuf->fdp,
efbuf->flags);
FILEDESC_SUNLOCK(efbuf->fdp);
error = export_kinfo_to_sb(efbuf);
FILEDESC_SLOCK(efbuf->fdp);
return (error);
}
static int
export_vnode_to_sb(struct vnode *vp, int fd, int fflags,
struct export_fd_buf *efbuf)
{
int error;
if (efbuf->remainder == 0)
return (0);
if (efbuf->fdp != NULL)
FILEDESC_SUNLOCK(efbuf->fdp);
export_vnode_to_kinfo(vp, fd, fflags, &efbuf->kif, efbuf->flags);
error = export_kinfo_to_sb(efbuf);
if (efbuf->fdp != NULL)
FILEDESC_SLOCK(efbuf->fdp);
return (error);
}
/*
* Store a process file descriptor information to sbuf.
*
* Takes a locked proc as argument, and returns with the proc unlocked.
*/
int
kern_proc_filedesc_out(struct proc *p, struct sbuf *sb, ssize_t maxlen,
int flags)
{
struct file *fp;
struct filedesc *fdp;
struct export_fd_buf *efbuf;
struct vnode *cttyvp, *textvp, *tracevp;
struct pwd *pwd;
int error, i, lastfile;
cap_rights_t rights;
PROC_LOCK_ASSERT(p, MA_OWNED);
/* ktrace vnode */
tracevp = p->p_tracevp;
if (tracevp != NULL)
vrefact(tracevp);
/* text vnode */
textvp = p->p_textvp;
if (textvp != NULL)
vrefact(textvp);
/* Controlling tty. */
cttyvp = NULL;
if (p->p_pgrp != NULL && p->p_pgrp->pg_session != NULL) {
cttyvp = p->p_pgrp->pg_session->s_ttyvp;
if (cttyvp != NULL)
vrefact(cttyvp);
}
fdp = fdhold(p);
PROC_UNLOCK(p);
efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK);
efbuf->fdp = NULL;
efbuf->sb = sb;
efbuf->remainder = maxlen;
efbuf->flags = flags;
if (tracevp != NULL)
export_vnode_to_sb(tracevp, KF_FD_TYPE_TRACE, FREAD | FWRITE,
efbuf);
if (textvp != NULL)
export_vnode_to_sb(textvp, KF_FD_TYPE_TEXT, FREAD, efbuf);
if (cttyvp != NULL)
export_vnode_to_sb(cttyvp, KF_FD_TYPE_CTTY, FREAD | FWRITE,
efbuf);
error = 0;
if (fdp == NULL)
goto fail;
efbuf->fdp = fdp;
FILEDESC_SLOCK(fdp);
pwd = pwd_hold_filedesc(fdp);
if (pwd != NULL) {
/* working directory */
if (pwd->pwd_cdir != NULL) {
vrefact(pwd->pwd_cdir);
export_vnode_to_sb(pwd->pwd_cdir, KF_FD_TYPE_CWD, FREAD, efbuf);
}
/* root directory */
if (pwd->pwd_rdir != NULL) {
vrefact(pwd->pwd_rdir);
export_vnode_to_sb(pwd->pwd_rdir, KF_FD_TYPE_ROOT, FREAD, efbuf);
}
/* jail directory */
if (pwd->pwd_jdir != NULL) {
vrefact(pwd->pwd_jdir);
export_vnode_to_sb(pwd->pwd_jdir, KF_FD_TYPE_JAIL, FREAD, efbuf);
}
}
lastfile = fdlastfile(fdp);
for (i = 0; fdp->fd_refcnt > 0 && i <= lastfile; i++) {
if ((fp = fdp->fd_ofiles[i].fde_file) == NULL)
continue;
#ifdef CAPABILITIES
rights = *cap_rights(fdp, i);
#else /* !CAPABILITIES */
rights = cap_no_rights;
#endif
/*
* Create sysctl entry. It is OK to drop the filedesc
* lock inside of export_file_to_sb() as we will
* re-validate and re-evaluate its properties when the
* loop continues.
*/
error = export_file_to_sb(fp, i, &rights, efbuf);
if (error != 0 || efbuf->remainder == 0)
break;
}
FILEDESC_SUNLOCK(fdp);
if (pwd != NULL)
pwd_drop(pwd);
fddrop(fdp);
fail:
free(efbuf, M_TEMP);
return (error);
}
#define FILEDESC_SBUF_SIZE (sizeof(struct kinfo_file) * 5)
/*
* Get per-process file descriptors for use by procstat(1), et al.
*/
static int
sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS)
{
struct sbuf sb;
struct proc *p;
ssize_t maxlen;
int error, error2, *name;
name = (int *)arg1;
sbuf_new_for_sysctl(&sb, NULL, FILEDESC_SBUF_SIZE, req);
sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p);
if (error != 0) {
sbuf_delete(&sb);
return (error);
}
maxlen = req->oldptr != NULL ? req->oldlen : -1;
error = kern_proc_filedesc_out(p, &sb, maxlen,
KERN_FILEDESC_PACK_KINFO);
error2 = sbuf_finish(&sb);
sbuf_delete(&sb);
return (error != 0 ? error : error2);
}
#ifdef COMPAT_FREEBSD7
#ifdef KINFO_OFILE_SIZE
CTASSERT(sizeof(struct kinfo_ofile) == KINFO_OFILE_SIZE);
#endif
static void
kinfo_to_okinfo(struct kinfo_file *kif, struct kinfo_ofile *okif)
{
okif->kf_structsize = sizeof(*okif);
okif->kf_type = kif->kf_type;
okif->kf_fd = kif->kf_fd;
okif->kf_ref_count = kif->kf_ref_count;
okif->kf_flags = kif->kf_flags & (KF_FLAG_READ | KF_FLAG_WRITE |
KF_FLAG_APPEND | KF_FLAG_ASYNC | KF_FLAG_FSYNC | KF_FLAG_NONBLOCK |
KF_FLAG_DIRECT | KF_FLAG_HASLOCK);
okif->kf_offset = kif->kf_offset;
if (kif->kf_type == KF_TYPE_VNODE)
okif->kf_vnode_type = kif->kf_un.kf_file.kf_file_type;
else
okif->kf_vnode_type = KF_VTYPE_VNON;
strlcpy(okif->kf_path, kif->kf_path, sizeof(okif->kf_path));
if (kif->kf_type == KF_TYPE_SOCKET) {
okif->kf_sock_domain = kif->kf_un.kf_sock.kf_sock_domain0;
okif->kf_sock_type = kif->kf_un.kf_sock.kf_sock_type0;
okif->kf_sock_protocol = kif->kf_un.kf_sock.kf_sock_protocol0;
okif->kf_sa_local = kif->kf_un.kf_sock.kf_sa_local;
okif->kf_sa_peer = kif->kf_un.kf_sock.kf_sa_peer;
} else {
okif->kf_sa_local.ss_family = AF_UNSPEC;
okif->kf_sa_peer.ss_family = AF_UNSPEC;
}
}
static int
export_vnode_for_osysctl(struct vnode *vp, int type, struct kinfo_file *kif,
struct kinfo_ofile *okif, struct filedesc *fdp, struct sysctl_req *req)
{
int error;
vrefact(vp);
FILEDESC_SUNLOCK(fdp);
export_vnode_to_kinfo(vp, type, 0, kif, KERN_FILEDESC_PACK_KINFO);
kinfo_to_okinfo(kif, okif);
error = SYSCTL_OUT(req, okif, sizeof(*okif));
FILEDESC_SLOCK(fdp);
return (error);
}
/*
* Get per-process file descriptors for use by procstat(1), et al.
*/
static int
sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS)
{
struct kinfo_ofile *okif;
struct kinfo_file *kif;
struct filedesc *fdp;
struct pwd *pwd;
int error, i, lastfile, *name;
struct file *fp;
struct proc *p;
name = (int *)arg1;
error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p);
if (error != 0)
return (error);
fdp = fdhold(p);
PROC_UNLOCK(p);
if (fdp == NULL)
return (ENOENT);
kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK);
okif = malloc(sizeof(*okif), M_TEMP, M_WAITOK);
FILEDESC_SLOCK(fdp);
pwd = pwd_hold_filedesc(fdp);
if (pwd != NULL) {
if (pwd->pwd_cdir != NULL)
export_vnode_for_osysctl(pwd->pwd_cdir, KF_FD_TYPE_CWD, kif,
okif, fdp, req);
if (pwd->pwd_rdir != NULL)
export_vnode_for_osysctl(pwd->pwd_rdir, KF_FD_TYPE_ROOT, kif,
okif, fdp, req);
if (pwd->pwd_jdir != NULL)
export_vnode_for_osysctl(pwd->pwd_jdir, KF_FD_TYPE_JAIL, kif,
okif, fdp, req);
}
lastfile = fdlastfile(fdp);
for (i = 0; fdp->fd_refcnt > 0 && i <= lastfile; i++) {
if ((fp = fdp->fd_ofiles[i].fde_file) == NULL)
continue;
export_file_to_kinfo(fp, i, NULL, kif, fdp,
KERN_FILEDESC_PACK_KINFO);
FILEDESC_SUNLOCK(fdp);
kinfo_to_okinfo(kif, okif);
error = SYSCTL_OUT(req, okif, sizeof(*okif));
FILEDESC_SLOCK(fdp);
if (error)
break;
}
FILEDESC_SUNLOCK(fdp);
if (pwd != NULL)
pwd_drop(pwd);
fddrop(fdp);
free(kif, M_TEMP);
free(okif, M_TEMP);
return (0);
}
static SYSCTL_NODE(_kern_proc, KERN_PROC_OFILEDESC, ofiledesc,
CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_ofiledesc,
"Process ofiledesc entries");
#endif /* COMPAT_FREEBSD7 */
int
vntype_to_kinfo(int vtype)
{
struct {
int vtype;
int kf_vtype;
} vtypes_table[] = {
{ VBAD, KF_VTYPE_VBAD },
{ VBLK, KF_VTYPE_VBLK },
{ VCHR, KF_VTYPE_VCHR },
{ VDIR, KF_VTYPE_VDIR },
{ VFIFO, KF_VTYPE_VFIFO },
{ VLNK, KF_VTYPE_VLNK },
{ VNON, KF_VTYPE_VNON },
{ VREG, KF_VTYPE_VREG },
{ VSOCK, KF_VTYPE_VSOCK }
};
unsigned int i;
/*
* Perform vtype translation.
*/
for (i = 0; i < nitems(vtypes_table); i++)
if (vtypes_table[i].vtype == vtype)
return (vtypes_table[i].kf_vtype);
return (KF_VTYPE_UNKNOWN);
}
static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc,
CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_filedesc,
"Process filedesc entries");
/*
* Store a process current working directory information to sbuf.
*
* Takes a locked proc as argument, and returns with the proc unlocked.
*/
int
kern_proc_cwd_out(struct proc *p, struct sbuf *sb, ssize_t maxlen)
{
struct filedesc *fdp;
struct pwd *pwd;
struct export_fd_buf *efbuf;
struct vnode *cdir;
int error;
PROC_LOCK_ASSERT(p, MA_OWNED);
fdp = fdhold(p);
PROC_UNLOCK(p);
if (fdp == NULL)
return (EINVAL);
efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK);
efbuf->fdp = fdp;
efbuf->sb = sb;
efbuf->remainder = maxlen;
FILEDESC_SLOCK(fdp);
pwd = FILEDESC_LOCKED_LOAD_PWD(fdp);
cdir = pwd->pwd_cdir;
if (cdir == NULL) {
error = EINVAL;
} else {
vrefact(cdir);
error = export_vnode_to_sb(cdir, KF_FD_TYPE_CWD, FREAD, efbuf);
}
FILEDESC_SUNLOCK(fdp);
fddrop(fdp);
free(efbuf, M_TEMP);
return (error);
}
/*
* Get per-process current working directory.
*/
static int
sysctl_kern_proc_cwd(SYSCTL_HANDLER_ARGS)
{
struct sbuf sb;
struct proc *p;
ssize_t maxlen;
int error, error2, *name;
name = (int *)arg1;
sbuf_new_for_sysctl(&sb, NULL, sizeof(struct kinfo_file), req);
sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p);
if (error != 0) {
sbuf_delete(&sb);
return (error);
}
maxlen = req->oldptr != NULL ? req->oldlen : -1;
error = kern_proc_cwd_out(p, &sb, maxlen);
error2 = sbuf_finish(&sb);
sbuf_delete(&sb);
return (error != 0 ? error : error2);
}
static SYSCTL_NODE(_kern_proc, KERN_PROC_CWD, cwd, CTLFLAG_RD|CTLFLAG_MPSAFE,
sysctl_kern_proc_cwd, "Process current working directory");
#ifdef DDB
/*
* For the purposes of debugging, generate a human-readable string for the
* file type.
*/
static const char *
file_type_to_name(short type)
{
switch (type) {
case 0:
return ("zero");
case DTYPE_VNODE:
return ("vnode");
case DTYPE_SOCKET:
return ("socket");
case DTYPE_PIPE:
return ("pipe");
case DTYPE_FIFO:
return ("fifo");
case DTYPE_KQUEUE:
return ("kqueue");
case DTYPE_CRYPTO:
return ("crypto");
case DTYPE_MQUEUE:
return ("mqueue");
case DTYPE_SHM:
return ("shm");
case DTYPE_SEM:
return ("ksem");
case DTYPE_PTS:
return ("pts");
case DTYPE_DEV:
return ("dev");
case DTYPE_PROCDESC:
return ("proc");
case DTYPE_LINUXEFD:
return ("levent");
case DTYPE_LINUXTFD:
return ("ltimer");
default:
return ("unkn");
}
}
/*
* For the purposes of debugging, identify a process (if any, perhaps one of
* many) that references the passed file in its file descriptor array. Return
* NULL if none.
*/
static struct proc *
file_to_first_proc(struct file *fp)
{
struct filedesc *fdp;
struct proc *p;
int n;
FOREACH_PROC_IN_SYSTEM(p) {
if (p->p_state == PRS_NEW)
continue;
fdp = p->p_fd;
if (fdp == NULL)
continue;
for (n = 0; n < fdp->fd_nfiles; n++) {
if (fp == fdp->fd_ofiles[n].fde_file)
return (p);
}
}
return (NULL);
}
static void
db_print_file(struct file *fp, int header)
{
#define XPTRWIDTH ((int)howmany(sizeof(void *) * NBBY, 4))
struct proc *p;
if (header)
db_printf("%*s %6s %*s %8s %4s %5s %6s %*s %5s %s\n",
XPTRWIDTH, "File", "Type", XPTRWIDTH, "Data", "Flag",
"GCFl", "Count", "MCount", XPTRWIDTH, "Vnode", "FPID",
"FCmd");
p = file_to_first_proc(fp);
db_printf("%*p %6s %*p %08x %04x %5d %6d %*p %5d %s\n", XPTRWIDTH,
fp, file_type_to_name(fp->f_type), XPTRWIDTH, fp->f_data,
fp->f_flag, 0, refcount_load(&fp->f_count), 0, XPTRWIDTH, fp->f_vnode,
p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-");
#undef XPTRWIDTH
}
DB_SHOW_COMMAND(file, db_show_file)
{
struct file *fp;
if (!have_addr) {
db_printf("usage: show file <addr>\n");
return;
}
fp = (struct file *)addr;
db_print_file(fp, 1);
}
DB_SHOW_COMMAND(files, db_show_files)
{
struct filedesc *fdp;
struct file *fp;
struct proc *p;
int header;
int n;
header = 1;
FOREACH_PROC_IN_SYSTEM(p) {
if (p->p_state == PRS_NEW)
continue;
if ((fdp = p->p_fd) == NULL)
continue;
for (n = 0; n < fdp->fd_nfiles; ++n) {
if ((fp = fdp->fd_ofiles[n].fde_file) == NULL)
continue;
db_print_file(fp, header);
header = 0;
}
}
}
#endif
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,
&openfiles, 0, "System-wide number of open files");
/* ARGSUSED*/
static void
filelistinit(void *dummy)
{
file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
filedesc0_zone = uma_zcreate("filedesc0", sizeof(struct filedesc0),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
pwd_zone = uma_zcreate("PWD", sizeof(struct pwd), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_SMR);
/*
* XXXMJG this is a temporary hack due to boot ordering issues against
* the vnode zone.
*/
vfs_smr = uma_zone_get_smr(pwd_zone);
mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF);
}
SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL);
/*-------------------------------------------------------------------*/
static int
badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
return (EBADF);
}
static int
badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred,
struct thread *td)
{
return (EINVAL);
}
static int
badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred,
struct thread *td)
{
return (EBADF);
}
static int
badfo_poll(struct file *fp, int events, struct ucred *active_cred,
struct thread *td)
{
return (0);
}
static int
badfo_kqfilter(struct file *fp, struct knote *kn)
{
return (EBADF);
}
static int
badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
struct thread *td)
{
return (EBADF);
}
static int
badfo_close(struct file *fp, struct thread *td)
{
return (0);
}
static int
badfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
struct thread *td)
{
return (EBADF);
}
static int
badfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
struct thread *td)
{
return (EBADF);
}
static int
badfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
struct thread *td)
{
return (EBADF);
}
static int
badfo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
{
return (0);
}
struct fileops badfileops = {
.fo_read = badfo_readwrite,
.fo_write = badfo_readwrite,
.fo_truncate = badfo_truncate,
.fo_ioctl = badfo_ioctl,
.fo_poll = badfo_poll,
.fo_kqfilter = badfo_kqfilter,
.fo_stat = badfo_stat,
.fo_close = badfo_close,
.fo_chmod = badfo_chmod,
.fo_chown = badfo_chown,
.fo_sendfile = badfo_sendfile,
.fo_fill_kinfo = badfo_fill_kinfo,
};
int
invfo_rdwr(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
return (EOPNOTSUPP);
}
int
invfo_truncate(struct file *fp, off_t length, struct ucred *active_cred,
struct thread *td)
{
return (EINVAL);
}
int
invfo_ioctl(struct file *fp, u_long com, void *data,
struct ucred *active_cred, struct thread *td)
{
return (ENOTTY);
}
int
invfo_poll(struct file *fp, int events, struct ucred *active_cred,
struct thread *td)
{
return (poll_no_poll(events));
}
int
invfo_kqfilter(struct file *fp, struct knote *kn)
{
return (EINVAL);
}
int
invfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
struct thread *td)
{
return (EINVAL);
}
int
invfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
struct thread *td)
{
return (EINVAL);
}
int
invfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
struct thread *td)
{
return (EINVAL);
}
/*-------------------------------------------------------------------*/
/*
* 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.
*
* XXX: we could give this one a cloning event handler if necessary.
*/
/* ARGSUSED */
static int
fdopen(struct cdev *dev, int mode, int 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);
}
static struct cdevsw fildesc_cdevsw = {
.d_version = D_VERSION,
.d_open = fdopen,
.d_name = "FD",
};
static void
fildesc_drvinit(void *unused)
{
struct cdev *dev;
dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 0, NULL,
UID_ROOT, GID_WHEEL, 0666, "fd/0");
make_dev_alias(dev, "stdin");
dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 1, NULL,
UID_ROOT, GID_WHEEL, 0666, "fd/1");
make_dev_alias(dev, "stdout");
dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 2, NULL,
UID_ROOT, GID_WHEEL, 0666, "fd/2");
make_dev_alias(dev, "stderr");
}
SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL);
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