/
kern_descrip.c
1479 lines (1288 loc) · 32.3 KB
/
kern_descrip.c
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/* $OpenBSD: kern_descrip.c,v 1.205 2022/01/20 11:06:57 bluhm Exp $ */
/* $NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $ */
/*
* 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/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/ucred.h>
#include <sys/unistd.h>
#include <sys/resourcevar.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <sys/event.h>
#include <sys/pool.h>
#include <sys/ktrace.h>
#include <sys/pledge.h>
#include <sys/pipe.h>
/*
* Descriptor management.
*
* We need to block interrupts as long as `fhdlk' is being taken
* with and without the KERNEL_LOCK().
*/
struct mutex fhdlk = MUTEX_INITIALIZER(IPL_MPFLOOR);
struct filelist filehead; /* head of list of open files */
int numfiles; /* actual number of open files */
static __inline void fd_used(struct filedesc *, int);
static __inline void fd_unused(struct filedesc *, int);
static __inline int find_next_zero(u_int *, int, u_int);
static __inline int fd_inuse(struct filedesc *, int);
int finishdup(struct proc *, struct file *, int, int, register_t *, int);
int find_last_set(struct filedesc *, int);
int dodup3(struct proc *, int, int, int, register_t *);
#define DUPF_CLOEXEC 0x01
#define DUPF_DUP2 0x02
struct pool file_pool;
struct pool fdesc_pool;
void
filedesc_init(void)
{
pool_init(&file_pool, sizeof(struct file), 0, IPL_MPFLOOR,
PR_WAITOK, "filepl", NULL);
pool_init(&fdesc_pool, sizeof(struct filedesc0), 0, IPL_NONE,
PR_WAITOK, "fdescpl", NULL);
LIST_INIT(&filehead);
}
static __inline int
find_next_zero (u_int *bitmap, int want, u_int bits)
{
int i, off, maxoff;
u_int sub;
if (want > bits)
return -1;
off = want >> NDENTRYSHIFT;
i = want & NDENTRYMASK;
if (i) {
sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i));
if (sub != ~0)
goto found;
off++;
}
maxoff = NDLOSLOTS(bits);
while (off < maxoff) {
if ((sub = bitmap[off]) != ~0)
goto found;
off++;
}
return -1;
found:
return (off << NDENTRYSHIFT) + ffs(~sub) - 1;
}
int
find_last_set(struct filedesc *fd, int last)
{
int off, i;
u_int *bitmap = fd->fd_lomap;
off = (last - 1) >> NDENTRYSHIFT;
while (off >= 0 && !bitmap[off])
off--;
if (off < 0)
return 0;
i = ((off + 1) << NDENTRYSHIFT) - 1;
if (i >= last)
i = last - 1;
while (i > 0 && !fd_inuse(fd, i))
i--;
return i;
}
static __inline int
fd_inuse(struct filedesc *fdp, int fd)
{
u_int off = fd >> NDENTRYSHIFT;
if (fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK)))
return 1;
return 0;
}
static __inline void
fd_used(struct filedesc *fdp, int fd)
{
u_int off = fd >> NDENTRYSHIFT;
fdp->fd_lomap[off] |= 1U << (fd & NDENTRYMASK);
if (fdp->fd_lomap[off] == ~0)
fdp->fd_himap[off >> NDENTRYSHIFT] |= 1U << (off & NDENTRYMASK);
if (fd > fdp->fd_lastfile)
fdp->fd_lastfile = fd;
fdp->fd_openfd++;
}
static __inline void
fd_unused(struct filedesc *fdp, int fd)
{
u_int off = fd >> NDENTRYSHIFT;
if (fd < fdp->fd_freefile)
fdp->fd_freefile = fd;
if (fdp->fd_lomap[off] == ~0)
fdp->fd_himap[off >> NDENTRYSHIFT] &= ~(1U << (off & NDENTRYMASK));
fdp->fd_lomap[off] &= ~(1U << (fd & NDENTRYMASK));
#ifdef DIAGNOSTIC
if (fd > fdp->fd_lastfile)
panic("fd_unused: fd_lastfile inconsistent");
#endif
if (fd == fdp->fd_lastfile)
fdp->fd_lastfile = find_last_set(fdp, fd);
fdp->fd_openfd--;
}
struct file *
fd_iterfile(struct file *fp, struct proc *p)
{
struct file *nfp;
unsigned int count;
mtx_enter(&fhdlk);
if (fp == NULL)
nfp = LIST_FIRST(&filehead);
else
nfp = LIST_NEXT(fp, f_list);
/* don't refcount when f_count == 0 to avoid race in fdrop() */
while (nfp != NULL) {
count = nfp->f_count;
if (count == 0) {
nfp = LIST_NEXT(nfp, f_list);
continue;
}
if (atomic_cas_uint(&nfp->f_count, count, count + 1) == count)
break;
}
mtx_leave(&fhdlk);
if (fp != NULL)
FRELE(fp, p);
return nfp;
}
struct file *
fd_getfile(struct filedesc *fdp, int fd)
{
struct file *fp;
vfs_stall_barrier();
if ((u_int)fd >= fdp->fd_nfiles)
return (NULL);
mtx_enter(&fdp->fd_fplock);
fp = fdp->fd_ofiles[fd];
if (fp != NULL)
atomic_inc_int(&fp->f_count);
mtx_leave(&fdp->fd_fplock);
return (fp);
}
struct file *
fd_getfile_mode(struct filedesc *fdp, int fd, int mode)
{
struct file *fp;
KASSERT(mode != 0);
fp = fd_getfile(fdp, fd);
if (fp == NULL)
return (NULL);
if ((fp->f_flag & mode) == 0) {
FRELE(fp, curproc);
return (NULL);
}
return (fp);
}
int
fd_checkclosed(struct filedesc *fdp, int fd, struct file *fp)
{
int closed;
mtx_enter(&fdp->fd_fplock);
KASSERT(fd < fdp->fd_nfiles);
closed = (fdp->fd_ofiles[fd] != fp);
mtx_leave(&fdp->fd_fplock);
return (closed);
}
/*
* System calls on descriptors.
*/
/*
* Duplicate a file descriptor.
*/
int
sys_dup(struct proc *p, void *v, register_t *retval)
{
struct sys_dup_args /* {
syscallarg(int) fd;
} */ *uap = v;
struct filedesc *fdp = p->p_fd;
int old = SCARG(uap, fd);
struct file *fp;
int new;
int error;
restart:
if ((fp = fd_getfile(fdp, old)) == NULL)
return (EBADF);
fdplock(fdp);
if ((error = fdalloc(p, 0, &new)) != 0) {
if (error == ENOSPC) {
fdexpand(p);
fdpunlock(fdp);
FRELE(fp, p);
goto restart;
}
fdpunlock(fdp);
FRELE(fp, p);
return (error);
}
/* No need for FRELE(), finishdup() uses current ref. */
return (finishdup(p, fp, old, new, retval, 0));
}
/*
* Duplicate a file descriptor to a particular value.
*/
int
sys_dup2(struct proc *p, void *v, register_t *retval)
{
struct sys_dup2_args /* {
syscallarg(int) from;
syscallarg(int) to;
} */ *uap = v;
return (dodup3(p, SCARG(uap, from), SCARG(uap, to), 0, retval));
}
int
sys_dup3(struct proc *p, void *v, register_t *retval)
{
struct sys_dup3_args /* {
syscallarg(int) from;
syscallarg(int) to;
syscallarg(int) flags;
} */ *uap = v;
if (SCARG(uap, from) == SCARG(uap, to))
return (EINVAL);
if (SCARG(uap, flags) & ~O_CLOEXEC)
return (EINVAL);
return (dodup3(p, SCARG(uap, from), SCARG(uap, to),
SCARG(uap, flags), retval));
}
int
dodup3(struct proc *p, int old, int new, int flags, register_t *retval)
{
struct filedesc *fdp = p->p_fd;
struct file *fp;
int dupflags, error, i;
restart:
if ((fp = fd_getfile(fdp, old)) == NULL)
return (EBADF);
if (old == new) {
/*
* NOTE! This doesn't clear the close-on-exec flag. This might
* or might not be the intended behavior from the start, but
* this is what everyone else does.
*/
*retval = new;
FRELE(fp, p);
return (0);
}
if ((u_int)new >= lim_cur(RLIMIT_NOFILE) ||
(u_int)new >= maxfiles) {
FRELE(fp, p);
return (EBADF);
}
fdplock(fdp);
if (new >= fdp->fd_nfiles) {
if ((error = fdalloc(p, new, &i)) != 0) {
if (error == ENOSPC) {
fdexpand(p);
fdpunlock(fdp);
FRELE(fp, p);
goto restart;
}
fdpunlock(fdp);
FRELE(fp, p);
return (error);
}
if (new != i)
panic("dup2: fdalloc");
fd_unused(fdp, new);
}
dupflags = DUPF_DUP2;
if (flags & O_CLOEXEC)
dupflags |= DUPF_CLOEXEC;
/* No need for FRELE(), finishdup() uses current ref. */
return (finishdup(p, fp, old, new, retval, dupflags));
}
/*
* The file control system call.
*/
int
sys_fcntl(struct proc *p, void *v, register_t *retval)
{
struct sys_fcntl_args /* {
syscallarg(int) fd;
syscallarg(int) cmd;
syscallarg(void *) arg;
} */ *uap = v;
int fd = SCARG(uap, fd);
struct filedesc *fdp = p->p_fd;
struct file *fp;
struct vnode *vp;
int i, prev, tmp, newmin, flg = F_POSIX;
struct flock fl;
int error = 0;
error = pledge_fcntl(p, SCARG(uap, cmd));
if (error)
return (error);
restart:
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
switch (SCARG(uap, cmd)) {
case F_DUPFD:
case F_DUPFD_CLOEXEC:
newmin = (long)SCARG(uap, arg);
if ((u_int)newmin >= lim_cur(RLIMIT_NOFILE) ||
(u_int)newmin >= maxfiles) {
error = EINVAL;
break;
}
fdplock(fdp);
if ((error = fdalloc(p, newmin, &i)) != 0) {
if (error == ENOSPC) {
fdexpand(p);
fdpunlock(fdp);
FRELE(fp, p);
goto restart;
}
fdpunlock(fdp);
FRELE(fp, p);
} else {
int dupflags = 0;
if (SCARG(uap, cmd) == F_DUPFD_CLOEXEC)
dupflags |= DUPF_CLOEXEC;
/* No need for FRELE(), finishdup() uses current ref. */
error = finishdup(p, fp, fd, i, retval, dupflags);
}
return (error);
case F_GETFD:
fdplock(fdp);
*retval = fdp->fd_ofileflags[fd] & UF_EXCLOSE ? 1 : 0;
fdpunlock(fdp);
break;
case F_SETFD:
fdplock(fdp);
if ((long)SCARG(uap, arg) & 1)
fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
else
fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
fdpunlock(fdp);
break;
case F_GETFL:
*retval = OFLAGS(fp->f_flag);
break;
case F_ISATTY:
vp = fp->f_data;
if (fp->f_type == DTYPE_VNODE && (vp->v_flag & VISTTY))
*retval = 1;
else {
*retval = 0;
error = ENOTTY;
}
break;
case F_SETFL:
do {
tmp = prev = fp->f_flag;
tmp &= ~FCNTLFLAGS;
tmp |= FFLAGS((long)SCARG(uap, arg)) & FCNTLFLAGS;
} while (atomic_cas_uint(&fp->f_flag, prev, tmp) != prev);
tmp = fp->f_flag & FNONBLOCK;
error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
if (error)
break;
tmp = fp->f_flag & FASYNC;
error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
if (!error)
break;
atomic_clearbits_int(&fp->f_flag, FNONBLOCK);
tmp = 0;
(void) (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
break;
case F_GETOWN:
tmp = 0;
error = (*fp->f_ops->fo_ioctl)
(fp, FIOGETOWN, (caddr_t)&tmp, p);
*retval = tmp;
break;
case F_SETOWN:
tmp = (long)SCARG(uap, arg);
error = ((*fp->f_ops->fo_ioctl)
(fp, FIOSETOWN, (caddr_t)&tmp, p));
break;
case F_SETLKW:
flg |= F_WAIT;
/* FALLTHROUGH */
case F_SETLK:
error = pledge_flock(p);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
error = EINVAL;
break;
}
vp = fp->f_data;
/* Copy in the lock structure */
error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
sizeof (fl));
if (error)
break;
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrflock(p, &fl);
#endif
if (fl.l_whence == SEEK_CUR) {
off_t offset = foffset(fp);
if (fl.l_start == 0 && fl.l_len < 0) {
/* lockf(3) compliance hack */
fl.l_len = -fl.l_len;
fl.l_start = offset - fl.l_len;
} else
fl.l_start += offset;
}
switch (fl.l_type) {
case F_RDLCK:
if ((fp->f_flag & FREAD) == 0) {
error = EBADF;
goto out;
}
atomic_setbits_int(&fdp->fd_flags, FD_ADVLOCK);
error = VOP_ADVLOCK(vp, fdp, F_SETLK, &fl, flg);
break;
case F_WRLCK:
if ((fp->f_flag & FWRITE) == 0) {
error = EBADF;
goto out;
}
atomic_setbits_int(&fdp->fd_flags, FD_ADVLOCK);
error = VOP_ADVLOCK(vp, fdp, F_SETLK, &fl, flg);
break;
case F_UNLCK:
error = VOP_ADVLOCK(vp, fdp, F_UNLCK, &fl, F_POSIX);
goto out;
default:
error = EINVAL;
goto out;
}
if (fd_checkclosed(fdp, fd, fp)) {
/*
* We have lost the race with close() or dup2();
* unlock, pretend that we've won the race and that
* lock had been removed by close()
*/
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
VOP_ADVLOCK(vp, fdp, F_UNLCK, &fl, F_POSIX);
fl.l_type = F_UNLCK;
}
goto out;
case F_GETLK:
error = pledge_flock(p);
if (error != 0)
break;
if (fp->f_type != DTYPE_VNODE) {
error = EINVAL;
break;
}
vp = fp->f_data;
/* Copy in the lock structure */
error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
sizeof (fl));
if (error)
break;
if (fl.l_whence == SEEK_CUR) {
off_t offset = foffset(fp);
if (fl.l_start == 0 && fl.l_len < 0) {
/* lockf(3) compliance hack */
fl.l_len = -fl.l_len;
fl.l_start = offset - fl.l_len;
} else
fl.l_start += offset;
}
if (fl.l_type != F_RDLCK &&
fl.l_type != F_WRLCK &&
fl.l_type != F_UNLCK &&
fl.l_type != 0) {
error = EINVAL;
break;
}
error = VOP_ADVLOCK(vp, fdp, F_GETLK, &fl, F_POSIX);
if (error)
break;
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrflock(p, &fl);
#endif
error = (copyout((caddr_t)&fl, (caddr_t)SCARG(uap, arg),
sizeof (fl)));
break;
default:
error = EINVAL;
break;
}
out:
FRELE(fp, p);
return (error);
}
/*
* Common code for dup, dup2, and fcntl(F_DUPFD).
*/
int
finishdup(struct proc *p, struct file *fp, int old, int new,
register_t *retval, int dupflags)
{
struct file *oldfp;
struct filedesc *fdp = p->p_fd;
int error;
fdpassertlocked(fdp);
KASSERT(fp->f_iflags & FIF_INSERTED);
if (fp->f_count >= FDUP_MAX_COUNT) {
error = EDEADLK;
goto fail;
}
oldfp = fd_getfile(fdp, new);
if ((dupflags & DUPF_DUP2) && oldfp == NULL) {
if (fd_inuse(fdp, new)) {
error = EBUSY;
goto fail;
}
fd_used(fdp, new);
}
/*
* Use `fd_fplock' to synchronize with fd_getfile() so that
* the function no longer creates a new reference to the old file.
*/
mtx_enter(&fdp->fd_fplock);
fdp->fd_ofiles[new] = fp;
mtx_leave(&fdp->fd_fplock);
fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] & ~UF_EXCLOSE;
if (dupflags & DUPF_CLOEXEC)
fdp->fd_ofileflags[new] |= UF_EXCLOSE;
*retval = new;
if (oldfp != NULL) {
knote_fdclose(p, new);
fdpunlock(fdp);
closef(oldfp, p);
} else {
fdpunlock(fdp);
}
return (0);
fail:
fdpunlock(fdp);
FRELE(fp, p);
return (error);
}
void
fdinsert(struct filedesc *fdp, int fd, int flags, struct file *fp)
{
struct file *fq;
fdpassertlocked(fdp);
mtx_enter(&fhdlk);
if ((fp->f_iflags & FIF_INSERTED) == 0) {
atomic_setbits_int(&fp->f_iflags, FIF_INSERTED);
if ((fq = fdp->fd_ofiles[0]) != NULL) {
LIST_INSERT_AFTER(fq, fp, f_list);
} else {
LIST_INSERT_HEAD(&filehead, fp, f_list);
}
}
mtx_leave(&fhdlk);
mtx_enter(&fdp->fd_fplock);
KASSERT(fdp->fd_ofiles[fd] == NULL);
fdp->fd_ofiles[fd] = fp;
mtx_leave(&fdp->fd_fplock);
fdp->fd_ofileflags[fd] |= (flags & UF_EXCLOSE);
}
void
fdremove(struct filedesc *fdp, int fd)
{
fdpassertlocked(fdp);
/*
* Use `fd_fplock' to synchronize with fd_getfile() so that
* the function no longer creates a new reference to the file.
*/
mtx_enter(&fdp->fd_fplock);
fdp->fd_ofiles[fd] = NULL;
mtx_leave(&fdp->fd_fplock);
fdp->fd_ofileflags[fd] = 0;
fd_unused(fdp, fd);
}
int
fdrelease(struct proc *p, int fd)
{
struct filedesc *fdp = p->p_fd;
struct file *fp;
fdpassertlocked(fdp);
fp = fd_getfile(fdp, fd);
if (fp == NULL) {
fdpunlock(fdp);
return (EBADF);
}
fdremove(fdp, fd);
knote_fdclose(p, fd);
fdpunlock(fdp);
return (closef(fp, p));
}
/*
* Close a file descriptor.
*/
int
sys_close(struct proc *p, void *v, register_t *retval)
{
struct sys_close_args /* {
syscallarg(int) fd;
} */ *uap = v;
int fd = SCARG(uap, fd), error;
struct filedesc *fdp = p->p_fd;
fdplock(fdp);
/* fdrelease unlocks fdp. */
error = fdrelease(p, fd);
return (error);
}
/*
* Return status information about a file descriptor.
*/
int
sys_fstat(struct proc *p, void *v, register_t *retval)
{
struct sys_fstat_args /* {
syscallarg(int) fd;
syscallarg(struct stat *) sb;
} */ *uap = v;
int fd = SCARG(uap, fd);
struct filedesc *fdp = p->p_fd;
struct file *fp;
struct stat ub;
int error;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
error = (*fp->f_ops->fo_stat)(fp, &ub, p);
FRELE(fp, p);
if (error == 0) {
/*
* Don't let non-root see generation numbers
* (for NFS security)
*/
if (suser(p))
ub.st_gen = 0;
error = copyout((caddr_t)&ub, (caddr_t)SCARG(uap, sb),
sizeof (ub));
}
#ifdef KTRACE
if (error == 0 && KTRPOINT(p, KTR_STRUCT))
ktrstat(p, &ub);
#endif
return (error);
}
/*
* Return pathconf information about a file descriptor.
*/
int
sys_fpathconf(struct proc *p, void *v, register_t *retval)
{
struct sys_fpathconf_args /* {
syscallarg(int) fd;
syscallarg(int) name;
} */ *uap = v;
int fd = SCARG(uap, fd);
struct filedesc *fdp = p->p_fd;
struct file *fp;
struct vnode *vp;
int error;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
switch (fp->f_type) {
case DTYPE_PIPE:
case DTYPE_SOCKET:
if (SCARG(uap, name) != _PC_PIPE_BUF) {
error = EINVAL;
break;
}
*retval = PIPE_BUF;
error = 0;
break;
case DTYPE_VNODE:
vp = fp->f_data;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_PATHCONF(vp, SCARG(uap, name), retval);
VOP_UNLOCK(vp);
break;
default:
error = EOPNOTSUPP;
break;
}
FRELE(fp, p);
return (error);
}
/*
* Allocate a file descriptor for the process.
*/
int
fdalloc(struct proc *p, int want, int *result)
{
struct filedesc *fdp = p->p_fd;
int lim, last, i;
u_int new, off;
fdpassertlocked(fdp);
/*
* Search for a free descriptor starting at the higher
* of want or fd_freefile. If that fails, consider
* expanding the ofile array.
*/
restart:
lim = min((int)lim_cur(RLIMIT_NOFILE), maxfiles);
last = min(fdp->fd_nfiles, lim);
if ((i = want) < fdp->fd_freefile)
i = fdp->fd_freefile;
off = i >> NDENTRYSHIFT;
new = find_next_zero(fdp->fd_himap, off,
(last + NDENTRIES - 1) >> NDENTRYSHIFT);
if (new != -1) {
i = find_next_zero(&fdp->fd_lomap[new],
new > off ? 0 : i & NDENTRYMASK,
NDENTRIES);
if (i == -1) {
/*
* Free file descriptor in this block was
* below want, try again with higher want.
*/
want = (new + 1) << NDENTRYSHIFT;
goto restart;
}
i += (new << NDENTRYSHIFT);
if (i < last) {
fd_used(fdp, i);
if (want <= fdp->fd_freefile)
fdp->fd_freefile = i;
*result = i;
fdp->fd_ofileflags[i] = 0;
if (ISSET(p->p_p->ps_flags, PS_PLEDGE))
fdp->fd_ofileflags[i] |= UF_PLEDGED;
return (0);
}
}
if (fdp->fd_nfiles >= lim)
return (EMFILE);
return (ENOSPC);
}
void
fdexpand(struct proc *p)
{
struct filedesc *fdp = p->p_fd;
int nfiles, oldnfiles;
size_t copylen;
struct file **newofile, **oldofile;
char *newofileflags;
u_int *newhimap, *newlomap;
fdpassertlocked(fdp);
oldnfiles = fdp->fd_nfiles;
oldofile = fdp->fd_ofiles;
/*
* No space in current array.
*/
if (fdp->fd_nfiles < NDEXTENT)
nfiles = NDEXTENT;
else
nfiles = 2 * fdp->fd_nfiles;
newofile = mallocarray(nfiles, OFILESIZE, M_FILEDESC, M_WAITOK);
/*
* Allocate all required chunks before calling free(9) to make
* sure that ``fd_ofiles'' stays valid if we go to sleep.
*/
if (NDHISLOTS(nfiles) > NDHISLOTS(fdp->fd_nfiles)) {
newhimap = mallocarray(NDHISLOTS(nfiles), sizeof(u_int),
M_FILEDESC, M_WAITOK);
newlomap = mallocarray(NDLOSLOTS(nfiles), sizeof(u_int),
M_FILEDESC, M_WAITOK);
}
newofileflags = (char *) &newofile[nfiles];
/*
* Copy the existing ofile and ofileflags arrays
* and zero the new portion of each array.
*/
copylen = sizeof(struct file *) * fdp->fd_nfiles;
memcpy(newofile, fdp->fd_ofiles, copylen);
memset((char *)newofile + copylen, 0,
nfiles * sizeof(struct file *) - copylen);
copylen = sizeof(char) * fdp->fd_nfiles;
memcpy(newofileflags, fdp->fd_ofileflags, copylen);
memset(newofileflags + copylen, 0, nfiles * sizeof(char) - copylen);
if (NDHISLOTS(nfiles) > NDHISLOTS(fdp->fd_nfiles)) {
copylen = NDHISLOTS(fdp->fd_nfiles) * sizeof(u_int);
memcpy(newhimap, fdp->fd_himap, copylen);
memset((char *)newhimap + copylen, 0,
NDHISLOTS(nfiles) * sizeof(u_int) - copylen);
copylen = NDLOSLOTS(fdp->fd_nfiles) * sizeof(u_int);
memcpy(newlomap, fdp->fd_lomap, copylen);
memset((char *)newlomap + copylen, 0,
NDLOSLOTS(nfiles) * sizeof(u_int) - copylen);
if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) {
free(fdp->fd_himap, M_FILEDESC,
NDHISLOTS(fdp->fd_nfiles) * sizeof(u_int));
free(fdp->fd_lomap, M_FILEDESC,
NDLOSLOTS(fdp->fd_nfiles) * sizeof(u_int));
}
fdp->fd_himap = newhimap;
fdp->fd_lomap = newlomap;
}
mtx_enter(&fdp->fd_fplock);
fdp->fd_ofiles = newofile;
mtx_leave(&fdp->fd_fplock);
fdp->fd_ofileflags = newofileflags;
fdp->fd_nfiles = nfiles;
if (oldnfiles > NDFILE)
free(oldofile, M_FILEDESC, oldnfiles * OFILESIZE);
}