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freebsd-skq/sys/kern/kern_descrip.c
Ed Maste dd38731e09 allow kern.proc.nfds sysctl in capability mode 
Reviewed by:	allanjude
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D7733
2016-09-01 02:51:50 +00:00

4107 lines
92 KiB
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/*-
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_capsicum.h"
#include "opt_compat.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/socketvar.h>
#include <sys/kdb.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_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 uma_zone_t file_zone;
static uma_zone_t filedesc0_zone;
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 int fd_last_used(struct filedesc *fdp, 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);
/*
* 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.
*/
volatile int openfiles; /* actual number of open files */
struct mtx sigio_lock; /* mtx to protect pointers to sigio */
void (*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 highest non-zero bit in the given bitmap, starting at 0 and
* not exceeding size - 1. Return -1 if not found.
*/
static int
fd_last_used(struct filedesc *fdp, int size)
{
NDSLOTTYPE *map = fdp->fd_map;
NDSLOTTYPE mask;
int off, minoff;
off = NDSLOT(size);
if (size % NDENTRIES) {
mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES));
if ((mask &= map[off]) != 0)
return (off * NDENTRIES + flsl(mask) - 1);
--off;
}
for (minoff = NDSLOT(0); off >= minoff; --off)
if (map[off] != 0)
return (off * NDENTRIES + flsl(map[off]) - 1);
return (-1);
}
static int
fdisused(struct filedesc *fdp, int fd)
{
KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0);
}
/*
* Mark a file descriptor as used.
*/
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_lastfile)
fdp->fd_lastfile = fd;
if (fd == fdp->fd_freefile)
fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles);
}
/*
* Mark a file descriptor as unused.
*/
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;
if (fd == fdp->fd_lastfile)
fdp->fd_lastfile = fd_last_used(fdp, 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
seq_write_begin(&fde->fde_seq);
#endif
fdefree_last(fde);
fde->fde_file = NULL;
fdunused(fdp, fd);
#ifdef CAPABILITIES
seq_write_end(&fde->fde_seq);
#endif
}
void
pwd_ensure_dirs(void)
{
struct filedesc *fdp;
fdp = curproc->p_fd;
FILEDESC_XLOCK(fdp);
if (fdp->fd_cdir == NULL) {
fdp->fd_cdir = rootvnode;
VREF(rootvnode);
}
if (fdp->fd_rdir == NULL) {
fdp->fd_rdir = rootvnode;
VREF(rootvnode);
}
FILEDESC_XUNLOCK(fdp);
}
/*
* 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] =
min((int)lim_cur(td, RLIMIT_NOFILE), maxfilesperproc);
#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;
cap_rights_t rights;
int error, flg, tmp;
uint64_t bsize;
off_t foffset;
error = 0;
flg = F_POSIX;
p = td->td_proc;
fdp = p->p_fd;
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_rights_init(&rights, CAP_FCNTL), 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_rights_init(&rights, CAP_FCNTL), 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_rights_init(&rights, CAP_FCNTL), 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_rights_init(&rights, CAP_FCNTL), 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)
return (error);
flg = F_REMOTE;
goto do_setlk;
case F_SETLKW:
flg |= F_WAIT;
/* FALLTHROUGH F_SETLK */
case F_SETLK:
do_setlk:
cap_rights_init(&rights, CAP_FLOCK);
error = fget_unlocked(fdp, fd, &rights, &fp, NULL);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
error = EBADF;
fdrop(fp, td);
break;
}
flp = (struct flock *)arg;
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;
}
PROC_LOCK(p->p_leader);
p->p_leader->p_flag |= P_ADVLOCK;
PROC_UNLOCK(p->p_leader);
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
flp, flg);
break;
case F_WRLCK:
if ((fp->f_flag & FWRITE) == 0) {
error = EBADF;
break;
}
PROC_LOCK(p->p_leader);
p->p_leader->p_flag |= P_ADVLOCK;
PROC_UNLOCK(p->p_leader);
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
flp, flg);
break;
case F_UNLCK:
error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
flp, flg);
break;
case F_UNLCKSYS:
/*
* Temporary api for testing remote lock
* infrastructure.
*/
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, &rights, &fp2, NULL);
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_rights_init(&rights, CAP_FLOCK), &fp, NULL);
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_RDAHEAD:
arg = arg ? 128 * 1024: 0;
/* FALLTHROUGH */
case F_READAHEAD:
error = fget_unlocked(fdp, fd,
cap_rights_init(&rights), &fp, NULL);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
fdrop(fp, td);
error = EBADF;
break;
}
vp = fp->f_vnode;
/*
* 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;
fp->f_seqcount = (arg + bsize - 1) / bsize;
atomic_set_int(&fp->f_flag, FRDAHEAD);
} else {
atomic_clear_int(&fp->f_flag, FRDAHEAD);
}
VOP_UNLOCK(vp, 0);
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;
int error, maxfd;
p = td->td_proc;
fdp = p->p_fd;
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;
}
/*
* 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)
goto unlock;
break;
case FDDUP_MUSTREPLACE:
/* Target file descriptor must exist. */
if (fget_locked(fdp, new) == NULL)
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_enable) {
PROC_LOCK(p);
error = racct_set(p, RACCT_NOFILE, new + 1);
PROC_UNLOCK(p);
if (error != 0) {
error = EMFILE;
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"));
oldfde = &fdp->fd_ofiles[old];
fhold(oldfde->fde_file);
newfde = &fdp->fd_ofiles[new];
delfp = newfde->fde_file;
/*
* Duplicate the source descriptor.
*/
#ifdef CAPABILITIES
seq_write_begin(&newfde->fde_seq);
#endif
filecaps_free(&newfde->fde_caps);
memcpy(newfde, oldfde, fde_change_size);
filecaps_copy(&oldfde->fde_caps, &newfde->fde_caps, true);
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
seq_write_end(&newfde->fde_seq);
#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);
}
return (error);
}
/*
* 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;
if (*sigiop == NULL)
return;
SIGIO_LOCK();
sigio = *sigiop;
if (sigio == NULL) {
SIGIO_UNLOCK();
return;
}
*(sigio->sio_myref) = NULL;
if ((sigio)->sio_pgid < 0) {
struct pgrp *pg = (sigio)->sio_pgrp;
PGRP_LOCK(pg);
SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
sigio, sio_pgsigio);
PGRP_UNLOCK(pg);
} else {
struct proc *p = (sigio)->sio_proc;
PROC_LOCK(p);
SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
sigio, sio_pgsigio);
PROC_UNLOCK(p);
}
SIGIO_UNLOCK();
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO);
}
/*
* Free a list of sigio structures.
* We only need to lock the SIGIO_LOCK because we have made ourselves
* inaccessible to callers of fsetown and therefore do not need to lock
* the proc or pgrp struct for the list manipulation.
*/
void
funsetownlst(struct sigiolst *sigiolst)
{
struct proc *p;
struct pgrp *pg;
struct sigio *sigio;
sigio = SLIST_FIRST(sigiolst);
if (sigio == NULL)
return;
p = NULL;
pg = NULL;
/*
* Every entry of the list should belong
* to a single proc or pgrp.
*/
if (sigio->sio_pgid < 0) {
pg = sigio->sio_pgrp;
PGRP_LOCK_ASSERT(pg, MA_NOTOWNED);
} else /* if (sigio->sio_pgid > 0) */ {
p = sigio->sio_proc;
PROC_LOCK_ASSERT(p, MA_NOTOWNED);
}
SIGIO_LOCK();
while ((sigio = SLIST_FIRST(sigiolst)) != NULL) {
*(sigio->sio_myref) = NULL;
if (pg != NULL) {
KASSERT(sigio->sio_pgid < 0,
("Proc sigio in pgrp sigio list"));
KASSERT(sigio->sio_pgrp == pg,
("Bogus pgrp in sigio list"));
PGRP_LOCK(pg);
SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio,
sio_pgsigio);
PGRP_UNLOCK(pg);
} else /* if (p != NULL) */ {
KASSERT(sigio->sio_pgid > 0,
("Pgrp sigio in proc sigio list"));
KASSERT(sigio->sio_proc == p,
("Bogus proc in sigio list"));
PROC_LOCK(p);
SLIST_REMOVE(&p->p_sigiolst, sigio, sigio,
sio_pgsigio);
PROC_UNLOCK(p);
}
SIGIO_UNLOCK();
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO);
SIGIO_LOCK();
}
SIGIO_UNLOCK();
}
/*
* This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
*
* After permission checking, add a sigio structure to the sigio list for
* the process or process group.
*/
int
fsetown(pid_t pgid, struct sigio **sigiop)
{
struct proc *proc;
struct pgrp *pgrp;
struct sigio *sigio;
int ret;
if (pgid == 0) {
funsetown(sigiop);
return (0);
}
ret = 0;
/* Allocate and fill in the new sigio out of locks. */
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);
if (pgid > 0) {
proc = pfind(pgid);
if (proc == NULL) {
ret = ESRCH;
goto fail;
}
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
PROC_UNLOCK(proc);
if (proc->p_session != curthread->td_proc->p_session) {
ret = EPERM;
goto fail;
}
pgrp = NULL;
} else /* if (pgid < 0) */ {
pgrp = pgfind(-pgid);
if (pgrp == NULL) {
ret = ESRCH;
goto fail;
}
PGRP_UNLOCK(pgrp);
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (pgrp->pg_session != curthread->td_proc->p_session) {
ret = EPERM;
goto fail;
}
proc = NULL;
}
funsetown(sigiop);
if (pgid > 0) {
PROC_LOCK(proc);
/*
* Since funsetownlst() is called without the proctree
* locked, we need to check for P_WEXIT.
* XXX: is ESRCH correct?
*/
if ((proc->p_flag & P_WEXIT) != 0) {
PROC_UNLOCK(proc);
ret = ESRCH;
goto fail;
}
SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
sigio->sio_proc = proc;
PROC_UNLOCK(proc);
} else {
PGRP_LOCK(pgrp);
SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
sigio->sio_pgrp = pgrp;
PGRP_UNLOCK(pgrp);
}
sx_sunlock(&proctree_lock);
SIGIO_LOCK();
*sigiop = sigio;
SIGIO_UNLOCK();
return (0);
fail:
sx_sunlock(&proctree_lock);
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO);
return (ret);
}
/*
* This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
*/
pid_t
fgetown(sigiop)
struct sigio **sigiop;
{
pid_t pgid;
SIGIO_LOCK();
pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0;
SIGIO_UNLOCK();
return (pgid);
}
/*
* 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.
*/
knote_fdclose(td, fd);
/*
* We need to notify mqueue if the object is of type mqueue.
*/
if (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));
}
/*
* Close open file descriptors.
*/
#ifndef _SYS_SYSPROTO_H_
struct closefrom_args {
int lowfd;
};
#endif
/* ARGSUSED */
int
sys_closefrom(struct thread *td, struct closefrom_args *uap)
{
struct filedesc *fdp;
int fd;
fdp = td->td_proc->p_fd;
AUDIT_ARG_FD(uap->lowfd);
/*
* Treat negative starting file descriptor values identical to
* closefrom(0) which closes all files.
*/
if (uap->lowfd < 0)
uap->lowfd = 0;
FILEDESC_SLOCK(fdp);
for (fd = uap->lowfd; fd <= fdp->fd_lastfile; fd++) {
if (fdp->fd_ofiles[fd].fde_file != NULL) {
FILEDESC_SUNLOCK(fdp);
(void)kern_close(td, fd);
FILEDESC_SLOCK(fdp);
}
}
FILEDESC_SUNLOCK(fdp);
return (0);
}
#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 */
/*
* 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;
cap_rights_t rights;
int error;
AUDIT_ARG_FD(fd);
error = fget(td, fd, cap_rights_init(&rights, CAP_FSTAT), &fp);
if (error != 0)
return (error);
AUDIT_ARG_FILE(td->td_proc, fp);
error = fo_stat(fp, sbp, td->td_ucred, td);
fdrop(fp, td);
#ifdef KTRACE
if (error == 0 && KTRPOINT(td, KTR_STRUCT))
ktrstat(sbp);
#endif
return (error);
}
/*
* Return status information about a file descriptor.
*/
#ifndef _SYS_SYSPROTO_H_
struct nfstat_args {
int fd;
struct nstat *sb;
};
#endif
/* ARGSUSED */
int
sys_nfstat(struct thread *td, struct nfstat_args *uap)
{
struct nstat nub;
struct stat ub;
int error;
error = kern_fstat(td, uap->fd, &ub);
if (error == 0) {
cvtnstat(&ub, &nub);
error = copyout(&nub, uap->sb, sizeof(nub));
}
return (error);
}
/*
* 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)
{
struct file *fp;
struct vnode *vp;
cap_rights_t rights;
int error;
error = fget(td, uap->fd, cap_rights_init(&rights, CAP_FPATHCONF), &fp);
if (error != 0)
return (error);
if (uap->name == _PC_ASYNC_IO) {
td->td_retval[0] = _POSIX_ASYNCHRONOUS_IO;
goto out;
}
vp = fp->f_vnode;
if (vp != NULL) {
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_PATHCONF(vp, uap->name, td->td_retval);
VOP_UNLOCK(vp, 0);
} else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) {
if (uap->name != _PC_PIPE_BUF) {
error = EINVAL;
} else {
td->td_retval[0] = PIPE_BUF;
error = 0;
}
} else {
error = EOPNOTSUPP;
}
out:
fdrop(fp, td);
return (error);
}
/*
* Initialize filecaps structure.
*/
void
filecaps_init(struct filecaps *fcaps)
{
bzero(fcaps, sizeof(*fcaps));
fcaps->fc_nioctls = -1;
}
/*
* 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.
*/
int
filecaps_copy(const struct filecaps *src, struct filecaps *dst, bool locked)
{
size_t size;
*dst = *src;
if (src->fc_ioctls == NULL)
return (0);
if (!locked)
return (1);
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);
bcopy(src->fc_ioctls, dst->fc_ioctls, size);
return (0);
}
/*
* 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));
}
/*
* 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;
/*
* If lastfile is -1 this struct filedesc was just allocated and we are
* growing it to accommodate for the one we are going to copy from. There
* is no need to have a lock on this one as it's not visible to anyone.
*/
if (fdp->fd_lastfile != -1)
FILEDESC_XLOCK_ASSERT(fdp);
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 (fd >= maxfd)
return (EMFILE);
if (fd >= fdp->fd_nfiles) {
allocfd = min(fd * 2, maxfd);
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(p);
error = racct_set(p, RACCT_NOFILE, allocfd);
PROC_UNLOCK(p);
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);
static struct timeval lastfail;
static int curfail;
KASSERT(resultfp != NULL, ("%s: resultfp == NULL", __func__));
if ((openfiles >= maxuserfiles &&
priv_check(td, PRIV_MAXFILES) != 0) ||
openfiles >= maxfiles) {
if (ppsratecheck(&lastfail, &curfail, 1)) {
printf("kern.maxfiles limit exceeded by uid %i, "
"please see tuning(7).\n", td->td_ucred->cr_ruid);
}
return (ENFILE);
}
atomic_add_int(&openfiles, 1);
fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO);
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
seq_write_begin(&fde->fde_seq);
#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
seq_write_end(&fde->fde_seq);
#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);
FILEDESC_XLOCK(fdp);
if ((error = fdalloc(td, 0, fd))) {
FILEDESC_XUNLOCK(fdp);
return (error);
}
fhold(fp);
_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)
{
struct filedesc0 *newfdp0;
struct filedesc *newfdp;
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_lastfile = -1;
newfdp->fd_files = (struct fdescenttbl *)&newfdp0->fd_dfiles;
newfdp->fd_files->fdt_nfiles = NDFILE;
if (fdp == NULL)
return (newfdp);
if (prepfiles && fdp->fd_lastfile >= newfdp->fd_nfiles)
fdgrowtable(newfdp, fdp->fd_lastfile + 1);
FILEDESC_SLOCK(fdp);
newfdp->fd_cdir = fdp->fd_cdir;
if (newfdp->fd_cdir)
VREF(newfdp->fd_cdir);
newfdp->fd_rdir = fdp->fd_rdir;
if (newfdp->fd_rdir)
VREF(newfdp->fd_rdir);
newfdp->fd_jdir = fdp->fd_jdir;
if (newfdp->fd_jdir)
VREF(newfdp->fd_jdir);
if (!prepfiles) {
FILEDESC_SUNLOCK(fdp);
} else {
while (fdp->fd_lastfile >= newfdp->fd_nfiles) {
FILEDESC_SUNLOCK(fdp);
fdgrowtable(newfdp, fdp->fd_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;
MPASS(fdp != NULL);
newfdp = fdinit(fdp, true);
/* copy all passable descriptors (i.e. not kqueue) */
newfdp->fd_freefile = -1;
for (i = 0; i <= fdp->fd_lastfile; ++i) {
ofde = &fdp->fd_ofiles[i];
if (ofde->fde_file == NULL ||
(ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0) {
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);
fhold(nfde->fde_file);
fdused_init(newfdp, i);
newfdp->fd_lastfile = 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;
MPASS(fdp != NULL);
newfdp = fdinit(fdp, true);
if (nfds > fdp->fd_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] > fdp->fd_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;
}
nfde = &newfdp->fd_ofiles[i];
*nfde = *ofde;
filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true);
fhold(nfde->fde_file);
fdused_init(newfdp, i);
newfdp->fd_lastfile = 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;
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) {
for (i = 0; i <= fdp->fd_lastfile; i++) {
fp = fdp->fd_ofiles[i].fde_file;
if (fp == NULL || fp->f_type != DTYPE_VNODE)
continue;
fhold(fp);
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;
for (i = 0; i <= fdp->fd_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 vnode *cdir, *jdir, *rdir;
p = td->td_proc;
fdp = p->p_fd;
MPASS(fdp != NULL);
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(p);
racct_set(p, RACCT_NOFILE, 0);
PROC_UNLOCK(p);
}
#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);
cdir = fdp->fd_cdir;
fdp->fd_cdir = NULL;
rdir = fdp->fd_rdir;
fdp->fd_rdir = NULL;
jdir = fdp->fd_jdir;
fdp->fd_jdir = NULL;
FILEDESC_XUNLOCK(fdp);
if (cdir != NULL)
vrele(cdir);
if (rdir != NULL)
vrele(rdir);
if (jdir != NULL)
vrele(jdir);
fdescfree_fds(td, fdp, 1);
}
void
fdescfree_remapped(struct filedesc *fdp)
{
if (fdp->fd_cdir != NULL)
vrele(fdp->fd_cdir);
if (fdp->fd_rdir != NULL)
vrele(fdp->fd_rdir);
if (fdp->fd_jdir != NULL)
vrele(fdp->fd_jdir);
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;
fdp = td->td_proc->p_fd;
KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
for (i = 0; i <= fdp->fd_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.
*
* XXXRW: Giant is not required for the caller, but often will be held; this
* makes it moderately likely the Giant will be recursed in the VFS case.
*/
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);
}
int
fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp, seq_t *seqp)
{
#ifdef CAPABILITIES
struct filedescent *fde;
#endif
struct fdescenttbl *fdt;
struct file *fp;
u_int count;
#ifdef CAPABILITIES
seq_t seq;
cap_rights_t haverights;
int error;
#endif
fdt = fdp->fd_files;
if ((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 = seq_read(fd_seq(fdt, fd));
fde = &fdt->fdt_ofiles[fd];
haverights = *cap_rights_fde(fde);
fp = fde->fde_file;
if (!seq_consistent(fd_seq(fdt, fd), seq)) {
cpu_spinwait();
continue;
}
#else
fp = fdt->fdt_ofiles[fd].fde_file;
#endif
if (fp == NULL)
return (EBADF);
#ifdef CAPABILITIES
error = cap_check(&haverights, needrightsp);
if (error != 0)
return (error);
#endif
retry:
count = fp->f_count;
if (count == 0) {
/*
* Force a reload. Other thread could reallocate the
* table before this fd was closed, so it possible that
* there is a stale fp pointer in cached version.
*/
fdt = *(struct fdescenttbl * volatile *)&(fdp->fd_files);
continue;
}
/*
* Use an acquire barrier to force re-reading of fdt so it is
* refreshed for verification.
*/
if (atomic_cmpset_acq_int(&fp->f_count, count, count + 1) == 0)
goto retry;
fdt = fdp->fd_files;
#ifdef CAPABILITIES
if (seq_consistent_nomb(fd_seq(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);
}
/*
* 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, seq_t *seqp)
{
struct filedesc *fdp;
struct file *fp;
int error;
*fpp = NULL;
fdp = td->td_proc->p_fd;
error = fget_unlocked(fdp, fd, needrightsp, &fp, seqp);
if (error != 0)
return (error);
if (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, NULL));
}
int
fget_mmap(struct thread *td, int fd, cap_rights_t *rightsp, u_char *maxprotp,
struct file **fpp)
{
int error;
#ifndef CAPABILITIES
error = _fget(td, fd, fpp, 0, rightsp, NULL);
if (maxprotp != NULL)
*maxprotp = VM_PROT_ALL;
#else
struct filedesc *fdp = td->td_proc->p_fd;
seq_t seq;
MPASS(cap_rights_is_set(rightsp, CAP_MMAP));
for (;;) {
error = _fget(td, fd, fpp, 0, rightsp, &seq);
if (error != 0)
return (error);
/*
* If requested, convert capability rights to access flags.
*/
if (maxprotp != NULL)
*maxprotp = cap_rights_to_vmprot(cap_rights(fdp, fd));
if (!fd_modified(fdp, fd, seq))
break;
fdrop(*fpp, td);
}
#endif
return (error);
}
int
fget_read(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp)
{
return (_fget(td, fd, fpp, FREAD, rightsp, NULL));
}
int
fget_write(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp)
{
return (_fget(td, fd, fpp, FWRITE, rightsp, NULL));
}
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, NULL));
#else
int error;
seq_t seq;
MPASS(cap_rights_is_set(rightsp, CAP_FCNTL));
for (;;) {
error = fget_unlocked(fdp, fd, rightsp, fpp, &seq);
if (error != 0)
return (error);
error = cap_fcntl_check(fdp, fd, needfcntl);
if (!fd_modified(fdp, fd, seq))
break;
fdrop(*fpp, td);
}
if (error != 0) {
fdrop(*fpp, td);
*fpp = NULL;
}
return (error);
#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, NULL);
if (error != 0)
return (error);
if (fp->f_vnode == NULL) {
error = EINVAL;
} else {
*vpp = fp->f_vnode;
vref(*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 filedesc *fdp;
struct file *fp;
#ifdef CAPABILITIES
int error;
#endif
fdp = td->td_proc->p_fd;
fp = fget_locked(fdp, fd);
if (fp == NULL || fp->f_ops == &badfileops)
return (EBADF);
#ifdef CAPABILITIES
error = cap_check(cap_rights(fdp, fd), needrightsp);
if (error != 0)
return (error);
#endif
if (fp->f_vnode == NULL)
return (EINVAL);
*vpp = fp->f_vnode;
vref(*vpp);
filecaps_copy(&fdp->fd_ofiles[fd].fde_caps, havecaps, true);
return (0);
}
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
/*
* Like fget() but loads the underlying socket, or returns an error if the
* descriptor does not represent a socket.
*
* We bump the ref count on the returned socket. XXX Also obtain the SX lock
* in the future.
*
* Note: fgetsock() and fputsock() are deprecated, as consumers should rely
* on their file descriptor reference to prevent the socket from being free'd
* during use.
*/
int
fgetsock(struct thread *td, int fd, cap_rights_t *rightsp, struct socket **spp,
u_int *fflagp)
{
struct file *fp;
int error;
*spp = NULL;
if (fflagp != NULL)
*fflagp = 0;
if ((error = _fget(td, fd, &fp, 0, rightsp, NULL)) != 0)
return (error);
if (fp->f_type != DTYPE_SOCKET) {
error = ENOTSOCK;
} else {
*spp = fp->f_data;
if (fflagp)
*fflagp = fp->f_flag;
SOCK_LOCK(*spp);
soref(*spp);
SOCK_UNLOCK(*spp);
}
fdrop(fp, td);
return (error);
}
/*
* Drop the reference count on the socket and XXX release the SX lock in the
* future. The last reference closes the socket.
*
* Note: fputsock() is deprecated, see comment for fgetsock().
*/
void
fputsock(struct socket *so)
{
ACCEPT_LOCK();
SOCK_LOCK(so);
CURVNET_SET(so->so_vnet);
sorele(so);
CURVNET_RESTORE();
}
/*
* Handle the last reference to a file being closed.
*/
int
_fdrop(struct file *fp, struct thread *td)
{
int error;
if (fp->f_count != 0)
panic("fdrop: count %d", fp->f_count);
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;
cap_rights_t rights;
int error;
error = fget(td, uap->fd, cap_rights_init(&rights, CAP_FLOCK), &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;
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);
}
fhold(fp);
newfde = &fdp->fd_ofiles[indx];
oldfde = &fdp->fd_ofiles[dfd];
#ifdef CAPABILITIES
seq_write_begin(&newfde->fde_seq);
#endif
memcpy(newfde, oldfde, fde_change_size);
filecaps_copy(&oldfde->fde_caps, &newfde->fde_caps, true);
#ifdef CAPABILITIES
seq_write_end(&newfde->fde_seq);
#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
seq_write_begin(&newfde->fde_seq);
#endif
memcpy(newfde, oldfde, fde_change_size);
oldfde->fde_file = NULL;
fdunused(fdp, dfd);
#ifdef CAPABILITIES
seq_write_end(&newfde->fde_seq);
#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;
FILEDESC_LOCK_ASSERT(fdp);
for (fd = 0; fd <= fdp->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);
}
/*
* 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 vnode *oldvp;
int error;
fdp = td->td_proc->p_fd;
FILEDESC_XLOCK(fdp);
if (chroot_allow_open_directories == 0 ||
(chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) {
error = chroot_refuse_vdir_fds(fdp);
if (error != 0) {
FILEDESC_XUNLOCK(fdp);
return (error);
}
}
oldvp = fdp->fd_rdir;
VREF(vp);
fdp->fd_rdir = vp;
if (fdp->fd_jdir == NULL) {
VREF(vp);
fdp->fd_jdir = vp;
}
FILEDESC_XUNLOCK(fdp);
vrele(oldvp);
return (0);
}
void
pwd_chdir(struct thread *td, struct vnode *vp)
{
struct filedesc *fdp;
struct vnode *oldvp;
fdp = td->td_proc->p_fd;
FILEDESC_XLOCK(fdp);
VNASSERT(vp->v_usecount > 0, vp,
("chdir to a vnode with zero usecount"));
oldvp = fdp->fd_cdir;
fdp->fd_cdir = vp;
FILEDESC_XUNLOCK(fdp);
vrele(oldvp);
}
/*
* 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 prison *pr;
struct proc *p;
int nrele;
if (vrefcnt(olddp) == 1)
return;
nrele = 0;
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);
if (fdp->fd_cdir == olddp) {
vref(newdp);
fdp->fd_cdir = newdp;
nrele++;
}
if (fdp->fd_rdir == olddp) {
vref(newdp);
fdp->fd_rdir = newdp;
nrele++;
}
if (fdp->fd_jdir == olddp) {
vref(newdp);
fdp->fd_jdir = newdp;
nrele++;
}
FILEDESC_XUNLOCK(fdp);
fddrop(fdp);
}
sx_sunlock(&allproc_lock);
if (rootvnode == olddp) {
vref(newdp);
rootvnode = newdp;
nrele++;
}
mtx_lock(&prison0.pr_mtx);
if (prison0.pr_root == olddp) {
vref(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) {
vref(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)
{
struct filedesc *fdp;
int i, count, slots;
if (*(int *)arg1 != 0)
return (EINVAL);
fdp = curproc->p_fd;
count = 0;
FILEDESC_SLOCK(fdp);
slots = NDSLOTS(fdp->fd_lastfile + 1);
for (i = 0; i < slots; i++)
count += bitcountl(fdp->fd_map[i]);
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;
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. */
if (fdp->fd_lastfile > 0)
n += fdp->fd_lastfile;
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);
for (n = 0; fdp->fd_refcnt > 0 && n <= fdp->fd_lastfile; ++n) {
if ((fp = fdp->fd_ofiles[n].fde_file) == NULL)
continue;
xf.xf_fd = n;
xf.xf_file = fp;
xf.xf_data = fp->f_data;
xf.xf_vnode = fp->f_vnode;
xf.xf_type = fp->f_type;
xf.xf_count = 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. */
static 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(&kif->kf_cap_rights);
kif->kf_fd = fd;
kif->kf_ref_count = 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(&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;
int error, i;
cap_rights_t rights;
PROC_LOCK_ASSERT(p, MA_OWNED);
/* ktrace vnode */
tracevp = p->p_tracevp;
if (tracevp != NULL)
vref(tracevp);
/* text vnode */
textvp = p->p_textvp;
if (textvp != NULL)
vref(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)
vref(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);
/* working directory */
if (fdp->fd_cdir != NULL) {
vref(fdp->fd_cdir);
export_vnode_to_sb(fdp->fd_cdir, KF_FD_TYPE_CWD, FREAD, efbuf);
}
/* root directory */
if (fdp->fd_rdir != NULL) {
vref(fdp->fd_rdir);
export_vnode_to_sb(fdp->fd_rdir, KF_FD_TYPE_ROOT, FREAD, efbuf);
}
/* jail directory */
if (fdp->fd_jdir != NULL) {
vref(fdp->fd_jdir);
export_vnode_to_sb(fdp->fd_jdir, KF_FD_TYPE_JAIL, FREAD, efbuf);
}
for (i = 0; fdp->fd_refcnt > 0 && i <= fdp->fd_lastfile; i++) {
if ((fp = fdp->fd_ofiles[i].fde_file) == NULL)
continue;
#ifdef CAPABILITIES
rights = *cap_rights(fdp, i);
#else /* !CAPABILITIES */
cap_rights_init(&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);
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 KINFO_OFILE_SIZE
CTASSERT(sizeof(struct kinfo_ofile) == KINFO_OFILE_SIZE);
#endif
#ifdef COMPAT_FREEBSD7
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;
okif->kf_vnode_type = kif->kf_vnode_type;
okif->kf_sock_domain = kif->kf_sock_domain;
okif->kf_sock_type = kif->kf_sock_type;
okif->kf_sock_protocol = kif->kf_sock_protocol;
strlcpy(okif->kf_path, kif->kf_path, sizeof(okif->kf_path));
okif->kf_sa_local = kif->kf_sa_local;
okif->kf_sa_peer = kif->kf_sa_peer;
}
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;
vref(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;
int error, i, *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);
if (fdp->fd_cdir != NULL)
export_vnode_for_osysctl(fdp->fd_cdir, KF_FD_TYPE_CWD, kif,
okif, fdp, req);
if (fdp->fd_rdir != NULL)
export_vnode_for_osysctl(fdp->fd_rdir, KF_FD_TYPE_ROOT, kif,
okif, fdp, req);
if (fdp->fd_jdir != NULL)
export_vnode_for_osysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif,
okif, fdp, req);
for (i = 0; fdp->fd_refcnt > 0 && i <= fdp->fd_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);
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 export_fd_buf *efbuf;
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);
if (fdp->fd_cdir == NULL)
error = EINVAL;
else {
vref(fdp->fd_cdir);
error = export_vnode_to_sb(fdp->fd_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 ("vnod");
case DTYPE_SOCKET:
return ("sock");
case DTYPE_PIPE:
return ("pipe");
case DTYPE_FIFO:
return ("fifo");
case DTYPE_KQUEUE:
return ("kque");
case DTYPE_CRYPTO:
return ("crpt");
case DTYPE_MQUEUE:
return ("mque");
case DTYPE_SHM:
return ("shm");
case DTYPE_SEM:
return ("ksem");
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_lastfile; n++) {
if (fp == fdp->fd_ofiles[n].fde_file)
return (p);
}
}
return (NULL);
}
static void
db_print_file(struct file *fp, int header)
{
struct proc *p;
if (header)
db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n",
"File", "Type", "Data", "Flag", "GCFl", "Count",
"MCount", "Vnode", "FPID", "FCmd");
p = file_to_first_proc(fp);
db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp,
file_type_to_name(fp->f_type), fp->f_data, fp->f_flag,
0, fp->f_count, 0, fp->f_vnode,
p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-");
}
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_lastfile; ++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,
__DEVOLATILE(int *, &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);
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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