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NetBSD/sys/kern/kern_descrip.c

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/* $NetBSD: kern_descrip.c,v 1.80 2001/07/18 05:34:37 thorpej 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_descrip.c 8.8 (Berkeley) 2/14/95
*/
#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/malloc.h>
#include <sys/pool.h>
#include <sys/syslog.h>
#include <sys/unistd.h>
#include <sys/resourcevar.h>
#include <sys/conf.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
/*
* Descriptor management.
*/
struct filelist filehead; /* head of list of open files */
int nfiles; /* actual number of open files */
struct pool file_pool; /* memory pool for file structures */
struct pool cwdi_pool; /* memory pool for cwdinfo structures */
struct pool filedesc0_pool; /* memory pool for filedesc0 structures */
static __inline void fd_used(struct filedesc *, int);
static __inline void fd_unused(struct filedesc *, int);
int finishdup(struct proc *, int, int, register_t *);
int fcntl_forfs(int, struct proc *, int, void *);
static __inline void
fd_used(struct filedesc *fdp, int fd)
{
if (fd > fdp->fd_lastfile)
fdp->fd_lastfile = fd;
}
static __inline void
fd_unused(struct filedesc *fdp, int fd)
{
if (fd < fdp->fd_freefile)
fdp->fd_freefile = fd;
#ifdef DIAGNOSTIC
if (fd > fdp->fd_lastfile)
panic("fd_unused: fd_lastfile inconsistent");
#endif
if (fd == fdp->fd_lastfile) {
do {
fd--;
} while (fd >= 0 && fdp->fd_ofiles[fd] == NULL);
fdp->fd_lastfile = fd;
}
}
struct file *
fd_getfile(struct filedesc *fdp, int fd)
{
struct file *fp;
if ((u_int) fd >= fdp->fd_nfiles || (fp = fdp->fd_ofiles[fd]) == NULL)
return (NULL);
if (FILE_IS_USABLE(fp) == 0)
return (NULL);
return (fp);
}
/*
* System calls on descriptors.
*/
/*
* Duplicate a file descriptor.
*/
/* ARGSUSED */
int
sys_dup(struct proc *p, void *v, register_t *retval)
{
struct sys_dup_args /* {
syscallarg(int) fd;
} */ *uap = v;
struct file *fp;
struct filedesc *fdp;
int old, new, error;
fdp = p->p_fd;
old = SCARG(uap, fd);
restart:
if ((fp = fd_getfile(fdp, old)) == NULL)
return (EBADF);
FILE_USE(fp);
if ((error = fdalloc(p, 0, &new)) != 0) {
if (error == ENOSPC) {
fdexpand(p);
FILE_UNUSE(fp, p);
goto restart;
}
FILE_UNUSE(fp, p);
return (error);
}
/* finishdup() will unuse the descriptors for us */
return (finishdup(p, old, new, retval));
}
/*
* Duplicate a file descriptor to a particular value.
*/
/* ARGSUSED */
int
sys_dup2(struct proc *p, void *v, register_t *retval)
{
struct sys_dup2_args /* {
syscallarg(int) from;
syscallarg(int) to;
} */ *uap = v;
struct file *fp;
struct filedesc *fdp;
int old, new, i, error;
fdp = p->p_fd;
old = SCARG(uap, from);
new = SCARG(uap, to);
restart:
if ((fp = fd_getfile(fdp, old)) == NULL)
return (EBADF);
if ((u_int)new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
(u_int)new >= maxfiles)
return (EBADF);
if (old == new) {
*retval = new;
return (0);
}
FILE_USE(fp);
if (new >= fdp->fd_nfiles) {
if ((error = fdalloc(p, new, &i)) != 0) {
if (error == ENOSPC) {
fdexpand(p);
FILE_UNUSE(fp, p);
goto restart;
}
FILE_UNUSE(fp, p);
return (error);
}
if (new != i)
panic("dup2: fdalloc");
}
/*
* finishdup() will close the file that's in the `new'
* slot, if there's one there.
*/
/* finishdup() will unuse the descriptors for us */
return (finishdup(p, old, new, retval));
}
/*
* The file control system call.
*/
/* ARGSUSED */
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;
struct filedesc *fdp;
struct file *fp;
struct vnode *vp;
int fd, i, tmp, error, flg, cmd, newmin;
struct flock fl;
fd = SCARG(uap, fd);
fdp = p->p_fd;
error = 0;
flg = F_POSIX;
restart:
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
FILE_USE(fp);
cmd = SCARG(uap, cmd);
if ((cmd & F_FSCTL)) {
error = fcntl_forfs(fd, p, cmd, SCARG(uap, arg));
goto out;
}
switch (cmd) {
case F_DUPFD:
newmin = (long)SCARG(uap, arg);
if ((u_int)newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
(u_int)newmin >= maxfiles) {
error = EINVAL;
goto out;
}
if ((error = fdalloc(p, newmin, &i)) != 0) {
if (error == ENOSPC) {
fdexpand(p);
FILE_UNUSE(fp, p);
goto restart;
}
goto out;
}
/* finishdup() will unuse the descriptors for us */
return (finishdup(p, fd, i, retval));
case F_GETFD:
*retval = fdp->fd_ofileflags[fd] & UF_EXCLOSE ? 1 : 0;
break;
case F_SETFD:
if ((long)SCARG(uap, arg) & 1)
fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
else
fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
break;
case F_GETFL:
*retval = OFLAGS(fp->f_flag);
break;
case F_SETFL:
tmp = FFLAGS((long)SCARG(uap, arg)) & FCNTLFLAGS;
error = (*fp->f_ops->fo_fcntl)(fp, F_SETFL, (caddr_t)&tmp, p);
if (error)
goto out;
fp->f_flag &= ~FCNTLFLAGS;
fp->f_flag |= tmp;
tmp = fp->f_flag & FNONBLOCK;
error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
if (error)
goto out;
tmp = fp->f_flag & FASYNC;
error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
if (error == 0)
goto out;
fp->f_flag &= ~FNONBLOCK;
tmp = 0;
(void) (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
break;
case F_GETOWN:
if (fp->f_type == DTYPE_SOCKET) {
*retval = ((struct socket *)fp->f_data)->so_pgid;
goto out;
}
error = (*fp->f_ops->fo_ioctl)
(fp, TIOCGPGRP, (caddr_t)retval, p);
*retval = -*retval;
break;
case F_SETOWN:
if (fp->f_type == DTYPE_SOCKET) {
((struct socket *)fp->f_data)->so_pgid =
(long)SCARG(uap, arg);
goto out;
}
if ((long)SCARG(uap, arg) <= 0) {
tmp = (-(long)SCARG(uap, arg));
} else {
struct proc *p1 = pfind((long)SCARG(uap, arg));
if (p1 == 0) {
error = ESRCH;
goto out;
}
tmp = (long)p1->p_pgrp->pg_id;
}
error = (*fp->f_ops->fo_ioctl)
(fp, TIOCSPGRP, (caddr_t)&tmp, p);
break;
case F_SETLKW:
flg |= F_WAIT;
/* Fall into F_SETLK */
case F_SETLK:
if (fp->f_type != DTYPE_VNODE) {
error = EINVAL;
goto out;
}
vp = (struct vnode *)fp->f_data;
/* Copy in the lock structure */
error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
sizeof(fl));
if (error)
goto out;
if (fl.l_whence == SEEK_CUR)
fl.l_start += fp->f_offset;
switch (fl.l_type) {
case F_RDLCK:
if ((fp->f_flag & FREAD) == 0) {
error = EBADF;
goto out;
}
p->p_flag |= P_ADVLOCK;
error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg);
goto out;
case F_WRLCK:
if ((fp->f_flag & FWRITE) == 0) {
error = EBADF;
goto out;
}
p->p_flag |= P_ADVLOCK;
error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg);
goto out;
case F_UNLCK:
error = VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &fl,
F_POSIX);
goto out;
default:
error = EINVAL;
goto out;
}
case F_GETLK:
if (fp->f_type != DTYPE_VNODE) {
error = EINVAL;
goto out;
}
vp = (struct vnode *)fp->f_data;
/* Copy in the lock structure */
error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
sizeof(fl));
if (error)
goto out;
if (fl.l_whence == SEEK_CUR)
fl.l_start += fp->f_offset;
if (fl.l_type != F_RDLCK &&
fl.l_type != F_WRLCK &&
fl.l_type != F_UNLCK) {
error = EINVAL;
goto out;
}
error = VOP_ADVLOCK(vp, (caddr_t)p, F_GETLK, &fl, F_POSIX);
if (error)
goto out;
error = copyout((caddr_t)&fl, (caddr_t)SCARG(uap, arg),
sizeof(fl));
break;
default:
error = EINVAL;
}
out:
FILE_UNUSE(fp, p);
return (error);
}
/*
* Common code for dup, dup2, and fcntl(F_DUPFD).
*/
int
finishdup(struct proc *p, int old, int new, register_t *retval)
{
struct filedesc *fdp;
struct file *fp, *delfp;
fdp = p->p_fd;
/*
* If there is a file in the new slot, remember it so we
* can close it after we've finished the dup. We need
* to do it after the dup is finished, since closing
* the file may block.
*
* Note: `old' is already used for us.
*/
delfp = fdp->fd_ofiles[new];
fp = fdp->fd_ofiles[old];
fdp->fd_ofiles[new] = fp;
fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
fp->f_count++;
/*
* Note, don't have to mark it "used" in the table if there
* was already a file in the `new' slot.
*/
if (delfp == NULL)
fd_used(fdp, new);
*retval = new;
FILE_UNUSE(fp, p);
if (delfp != NULL) {
FILE_USE(delfp);
(void) closef(delfp, p);
}
return (0);
}
void
fdremove(struct filedesc *fdp, int fd)
{
fdp->fd_ofiles[fd] = NULL;
fd_unused(fdp, fd);
}
int
fdrelease(struct proc *p, int fd)
{
struct filedesc *fdp;
struct file **fpp, *fp;
fdp = p->p_fd;
fpp = &fdp->fd_ofiles[fd];
fp = *fpp;
if (fp == NULL)
return (EBADF);
FILE_USE(fp);
*fpp = NULL;
fdp->fd_ofileflags[fd] = 0;
fd_unused(fdp, fd);
return (closef(fp, p));
}
/*
* Close a file descriptor.
*/
/* ARGSUSED */
int
sys_close(struct proc *p, void *v, register_t *retval)
{
struct sys_close_args /* {
syscallarg(int) fd;
} */ *uap = v;
int fd;
struct filedesc *fdp;
struct file *fp;
fd = SCARG(uap, fd);
fdp = p->p_fd;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
return (fdrelease(p, fd));
}
/*
* Return status information about a file descriptor.
*/
/* ARGSUSED */
int
sys___fstat13(struct proc *p, void *v, register_t *retval)
{
struct sys___fstat13_args /* {
syscallarg(int) fd;
syscallarg(struct stat *) sb;
} */ *uap = v;
int fd;
struct filedesc *fdp;
struct file *fp;
struct stat ub;
int error;
fd = SCARG(uap, fd);
fdp = p->p_fd;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
FILE_USE(fp);
error = (*fp->f_ops->fo_stat)(fp, &ub, p);
FILE_UNUSE(fp, p);
if (error == 0)
error = copyout(&ub, SCARG(uap, sb), sizeof(ub));
return (error);
}
/*
* Return pathconf information about a file descriptor.
*/
/* ARGSUSED */
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;
struct filedesc *fdp;
struct file *fp;
struct vnode *vp;
int error;
fd = SCARG(uap, fd);
fdp = p->p_fd;
error = 0;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
FILE_USE(fp);
switch (fp->f_type) {
case DTYPE_SOCKET:
case DTYPE_PIPE:
if (SCARG(uap, name) != _PC_PIPE_BUF)
error = EINVAL;
else
*retval = PIPE_BUF;
break;
case DTYPE_VNODE:
vp = (struct vnode *)fp->f_data;
error = VOP_PATHCONF(vp, SCARG(uap, name), retval);
break;
default:
panic("fpathconf");
}
FILE_UNUSE(fp, p);
return (error);
}
/*
* Allocate a file descriptor for the process.
*/
int fdexpanded; /* XXX: what else uses this? */
int
fdalloc(struct proc *p, int want, int *result)
{
struct filedesc *fdp;
int i, lim, last;
fdp = p->p_fd;
/*
* Search for a free descriptor starting at the higher
* of want or fd_freefile. If that fails, consider
* expanding the ofile array.
*/
lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
for (;;) {
last = min(fdp->fd_nfiles, lim);
if ((i = want) < fdp->fd_freefile)
i = fdp->fd_freefile;
for (; i < last; i++) {
if (fdp->fd_ofiles[i] == NULL) {
fd_used(fdp, i);
if (want <= fdp->fd_freefile)
fdp->fd_freefile = i;
*result = i;
return (0);
}
}
/* No space in current array. Expand? */
if (fdp->fd_nfiles >= lim)
return (EMFILE);
/* Let the caller do it. */
return (ENOSPC);
}
}
void
fdexpand(struct proc *p)
{
struct filedesc *fdp;
int i, nfiles;
struct file **newofile;
char *newofileflags;
fdp = p->p_fd;
if (fdp->fd_nfiles < NDEXTENT)
nfiles = NDEXTENT;
else
nfiles = 2 * fdp->fd_nfiles;
newofile = malloc(nfiles * OFILESIZE, M_FILEDESC, M_WAITOK);
newofileflags = (char *) &newofile[nfiles];
/*
* Copy the existing ofile and ofileflags arrays
* and zero the new portion of each array.
*/
memcpy(newofile, fdp->fd_ofiles,
(i = sizeof(struct file *) * fdp->fd_nfiles));
memset((char *)newofile + i, 0,
nfiles * sizeof(struct file *) - i);
memcpy(newofileflags, fdp->fd_ofileflags,
(i = sizeof(char) * fdp->fd_nfiles));
memset(newofileflags + i, 0, nfiles * sizeof(char) - i);
if (fdp->fd_nfiles > NDFILE)
free(fdp->fd_ofiles, M_FILEDESC);
fdp->fd_ofiles = newofile;
fdp->fd_ofileflags = newofileflags;
fdp->fd_nfiles = nfiles;
fdexpanded++;
}
/*
* Check to see whether n user file descriptors
* are available to the process p.
*/
int
fdavail(struct proc *p, int n)
{
struct filedesc *fdp;
struct file **fpp;
int i, lim;
fdp = p->p_fd;
lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
return (1);
fpp = &fdp->fd_ofiles[fdp->fd_freefile];
for (i = min(lim,fdp->fd_nfiles) - fdp->fd_freefile; --i >= 0; fpp++)
if (*fpp == NULL && --n <= 0)
return (1);
return (0);
}
/*
* Initialize the data structures necessary for managing files.
*/
void
finit(void)
{
pool_init(&file_pool, sizeof(struct file), 0, 0, 0, "filepl",
0, pool_page_alloc_nointr, pool_page_free_nointr, M_FILE);
pool_init(&cwdi_pool, sizeof(struct cwdinfo), 0, 0, 0, "cwdipl",
0, pool_page_alloc_nointr, pool_page_free_nointr, M_FILEDESC);
pool_init(&filedesc0_pool, sizeof(struct filedesc0), 0, 0, 0, "fdescpl",
0, pool_page_alloc_nointr, pool_page_free_nointr, M_FILEDESC);
}
/*
* Create a new open file structure and allocate
* a file decriptor for the process that refers to it.
*/
int
falloc(struct proc *p, struct file **resultfp, int *resultfd)
{
struct file *fp, *fq;
int error, i;
restart:
if ((error = fdalloc(p, 0, &i)) != 0) {
if (error == ENOSPC) {
fdexpand(p);
goto restart;
}
return (error);
}
if (nfiles >= maxfiles) {
tablefull("file", "increase kern.maxfiles or MAXFILES");
return (ENFILE);
}
/*
* Allocate a new file descriptor.
* If the process has file descriptor zero open, add to the list
* of open files at that point, otherwise put it at the front of
* the list of open files.
*/
nfiles++;
fp = pool_get(&file_pool, PR_WAITOK);
memset(fp, 0, sizeof(struct file));
fp->f_iflags = FIF_LARVAL;
if ((fq = p->p_fd->fd_ofiles[0]) != NULL) {
LIST_INSERT_AFTER(fq, fp, f_list);
} else {
LIST_INSERT_HEAD(&filehead, fp, f_list);
}
p->p_fd->fd_ofiles[i] = fp;
fp->f_count = 1;
fp->f_cred = p->p_ucred;
crhold(fp->f_cred);
if (resultfp) {
FILE_USE(fp);
*resultfp = fp;
}
if (resultfd)
*resultfd = i;
return (0);
}
/*
* Free a file descriptor.
*/
void
ffree(struct file *fp)
{
#ifdef DIAGNOSTIC
if (fp->f_usecount)
panic("ffree");
#endif
LIST_REMOVE(fp, f_list);
crfree(fp->f_cred);
#ifdef DIAGNOSTIC
fp->f_count = 0;
#endif
nfiles--;
pool_put(&file_pool, fp);
}
/*
* Create an initial cwdinfo structure, using the same current and root
* directories as p.
*/
struct cwdinfo *
cwdinit(struct proc *p)
{
struct cwdinfo *cwdi;
cwdi = pool_get(&cwdi_pool, PR_WAITOK);
cwdi->cwdi_cdir = p->p_cwdi->cwdi_cdir;
if (cwdi->cwdi_cdir)
VREF(cwdi->cwdi_cdir);
cwdi->cwdi_rdir = p->p_cwdi->cwdi_rdir;
if (cwdi->cwdi_rdir)
VREF(cwdi->cwdi_rdir);
cwdi->cwdi_cmask = p->p_cwdi->cwdi_cmask;
cwdi->cwdi_refcnt = 1;
return (cwdi);
}
/*
* Make p2 share p1's cwdinfo.
*/
void
cwdshare(struct proc *p1, struct proc *p2)
{
p2->p_cwdi = p1->p_cwdi;
p1->p_cwdi->cwdi_refcnt++;
}
/*
* Make this process not share its cwdinfo structure, maintaining
* all cwdinfo state.
*/
void
cwdunshare(struct proc *p)
{
struct cwdinfo *newcwdi;
if (p->p_cwdi->cwdi_refcnt == 1)
return;
newcwdi = cwdinit(p);
cwdfree(p);
p->p_cwdi = newcwdi;
}
/*
* Release a cwdinfo structure.
*/
void
cwdfree(struct proc *p)
{
struct cwdinfo *cwdi;
cwdi = p->p_cwdi;
if (--cwdi->cwdi_refcnt > 0)
return;
p->p_cwdi = NULL;
vrele(cwdi->cwdi_cdir);
if (cwdi->cwdi_rdir)
vrele(cwdi->cwdi_rdir);
pool_put(&cwdi_pool, cwdi);
}
/*
* Create an initial filedesc structure, using the same current and root
* directories as p.
*/
struct filedesc *
fdinit(struct proc *p)
{
struct filedesc0 *newfdp;
newfdp = pool_get(&filedesc0_pool, PR_WAITOK);
memset(newfdp, 0, sizeof(struct filedesc0));
fdinit1(newfdp);
return (&newfdp->fd_fd);
}
/*
* Initialize a file descriptor table.
*/
void
fdinit1(struct filedesc0 *newfdp)
{
newfdp->fd_fd.fd_refcnt = 1;
newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
newfdp->fd_fd.fd_nfiles = NDFILE;
}
/*
* Make p2 share p1's filedesc structure.
*/
void
fdshare(struct proc *p1, struct proc *p2)
{
p2->p_fd = p1->p_fd;
p1->p_fd->fd_refcnt++;
}
/*
* Make this process not share its filedesc structure, maintaining
* all file descriptor state.
*/
void
fdunshare(struct proc *p)
{
struct filedesc *newfd;
if (p->p_fd->fd_refcnt == 1)
return;
newfd = fdcopy(p);
fdfree(p);
p->p_fd = newfd;
}
/*
* Clear a process's fd table.
*/
void
fdclear(struct proc *p)
{
struct filedesc *newfd;
newfd = fdinit(p);
fdfree(p);
p->p_fd = newfd;
}
/*
* Copy a filedesc structure.
*/
struct filedesc *
fdcopy(struct proc *p)
{
struct filedesc *newfdp, *fdp;
struct file **fpp;
int i;
fdp = p->p_fd;
newfdp = pool_get(&filedesc0_pool, PR_WAITOK);
memcpy(newfdp, fdp, sizeof(struct filedesc));
newfdp->fd_refcnt = 1;
/*
* If the number of open files fits in the internal arrays
* of the open file structure, use them, otherwise allocate
* additional memory for the number of descriptors currently
* in use.
*/
if (newfdp->fd_lastfile < NDFILE) {
newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles;
newfdp->fd_ofileflags =
((struct filedesc0 *) newfdp)->fd_dfileflags;
i = NDFILE;
} else {
/*
* Compute the smallest multiple of NDEXTENT needed
* for the file descriptors currently in use,
* allowing the table to shrink.
*/
i = newfdp->fd_nfiles;
while (i >= 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
i /= 2;
newfdp->fd_ofiles = malloc(i * OFILESIZE, M_FILEDESC, M_WAITOK);
newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
}
newfdp->fd_nfiles = i;
memcpy(newfdp->fd_ofiles, fdp->fd_ofiles, i * sizeof(struct file **));
memcpy(newfdp->fd_ofileflags, fdp->fd_ofileflags, i * sizeof(char));
fpp = newfdp->fd_ofiles;
for (i = newfdp->fd_lastfile; i >= 0; i--, fpp++)
if (*fpp != NULL)
(*fpp)->f_count++;
return (newfdp);
}
/*
* Release a filedesc structure.
*/
void
fdfree(struct proc *p)
{
struct filedesc *fdp;
struct file **fpp, *fp;
int i;
fdp = p->p_fd;
if (--fdp->fd_refcnt > 0)
return;
fpp = fdp->fd_ofiles;
for (i = fdp->fd_lastfile; i >= 0; i--, fpp++) {
fp = *fpp;
if (fp != NULL) {
*fpp = NULL;
FILE_USE(fp);
(void) closef(fp, p);
}
}
p->p_fd = NULL;
if (fdp->fd_nfiles > NDFILE)
free(fdp->fd_ofiles, M_FILEDESC);
pool_put(&filedesc0_pool, fdp);
}
/*
* Internal form of close.
* Decrement reference count on file structure.
* Note: p may be NULL when closing a file
* that was being passed in a message.
*
* Note: we expect the caller is holding a usecount, and expects us
* to drop it (the caller thinks the file is going away forever).
*/
int
closef(struct file *fp, struct proc *p)
{
struct vnode *vp;
struct flock lf;
int error;
if (fp == NULL)
return (0);
/*
* POSIX record locking dictates that any close releases ALL
* locks owned by this process. This is handled by setting
* a flag in the unlock to free ONLY locks obeying POSIX
* semantics, and not to free BSD-style file locks.
* If the descriptor was in a message, POSIX-style locks
* aren't passed with the descriptor.
*/
if (p && (p->p_flag & P_ADVLOCK) && fp->f_type == DTYPE_VNODE) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = (struct vnode *)fp->f_data;
(void) VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_POSIX);
}
/*
* If WANTCLOSE is set, then the reference count on the file
* is 0, but there were multiple users of the file. This can
* happen if a filedesc structure is shared by multiple
* processes.
*/
if (fp->f_iflags & FIF_WANTCLOSE) {
/*
* Another user of the file is already closing, and is
* simply waiting for other users of the file to drain.
* Release our usecount, and wake up the closer if it
* is the only remaining use.
*/
#ifdef DIAGNOSTIC
if (fp->f_count != 0)
panic("closef: wantclose and count != 0");
if (fp->f_usecount < 2)
panic("closef: wantclose and usecount < 2");
#endif
if (--fp->f_usecount == 1)
wakeup(&fp->f_usecount);
return (0);
} else {
/*
* Decrement the reference count. If we were not the
* last reference, then release our use and just
* return.
*/
if (--fp->f_count > 0) {
#ifdef DIAGNOSTIC
if (fp->f_usecount < 1)
panic("closef: no wantclose and usecount < 1");
#endif
fp->f_usecount--;
return (0);
}
if (fp->f_count < 0)
panic("closef: count < 0");
}
/*
* The reference count is now 0. However, there may be
* multiple potential users of this file. This can happen
* if multiple processes shared a single filedesc structure.
*
* Notify these potential users that the file is closing.
* This will prevent them from adding additional uses to
* the file.
*/
fp->f_iflags |= FIF_WANTCLOSE;
/*
* We expect the caller to add a use to the file. So, if we
* are the last user, usecount will be 1. If it is not, we
* must wait for the usecount to drain. When it drains back
* to 1, we will be awakened so that we may proceed with the
* close.
*/
#ifdef DIAGNOSTIC
if (fp->f_usecount < 1)
panic("closef: usecount < 1");
#endif
while (fp->f_usecount > 1)
(void) tsleep(&fp->f_usecount, PRIBIO, "closef", 0);
#ifdef DIAGNOSTIC
if (fp->f_usecount != 1)
panic("closef: usecount != 1");
#endif
if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = (struct vnode *)fp->f_data;
(void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
}
if (fp->f_ops)
error = (*fp->f_ops->fo_close)(fp, p);
else
error = 0;
/* Nothing references the file now, drop the final use (us). */
fp->f_usecount--;
ffree(fp);
return (error);
}
/*
* Apply an advisory lock on a file descriptor.
*
* Just attempt to get a record lock of the requested type on
* the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
*/
/* ARGSUSED */
int
sys_flock(struct proc *p, void *v, register_t *retval)
{
struct sys_flock_args /* {
syscallarg(int) fd;
syscallarg(int) how;
} */ *uap = v;
int fd, how, error;
struct filedesc *fdp;
struct file *fp;
struct vnode *vp;
struct flock lf;
fd = SCARG(uap, fd);
how = SCARG(uap, how);
fdp = p->p_fd;
error = 0;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
FILE_USE(fp);
if (fp->f_type != DTYPE_VNODE) {
error = EOPNOTSUPP;
goto out;
}
vp = (struct vnode *)fp->f_data;
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
if (how & LOCK_UN) {
lf.l_type = F_UNLCK;
fp->f_flag &= ~FHASLOCK;
error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
goto out;
}
if (how & LOCK_EX)
lf.l_type = F_WRLCK;
else if (how & LOCK_SH)
lf.l_type = F_RDLCK;
else {
error = EINVAL;
goto out;
}
fp->f_flag |= FHASLOCK;
if (how & LOCK_NB)
error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK);
else
error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf,
F_FLOCK|F_WAIT);
out:
FILE_UNUSE(fp, p);
return (error);
}
/*
* File Descriptor pseudo-device driver (/dev/fd/).
*
* Opening minor device N dup()s the file (if any) connected to file
* descriptor N belonging to the calling process. Note that this driver
* consists of only the ``open()'' routine, because all subsequent
* references to this file will be direct to the other driver.
*/
/* ARGSUSED */
int
filedescopen(dev_t dev, int mode, int type, struct proc *p)
{
/*
* XXX Kludge: set p->p_dupfd to contain the value of the
* the file descriptor being sought for duplication. The error
* return ensures that the vnode for this device will be released
* by vn_open. Open will detect this special error and take the
* actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
* will simply report the error.
*/
p->p_dupfd = minor(dev);
return (ENODEV);
}
/*
* Duplicate the specified descriptor to a free descriptor.
*/
int
dupfdopen(struct proc *p, int indx, int dfd, int mode, int error)
{
struct filedesc *fdp;
struct file *wfp, *fp;
fdp = p->p_fd;
/*
* 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, reject. Note, check for new == old is necessary as
* falloc could allocate an already closed to-be-dup'd descriptor
* as the new descriptor.
*/
fp = fdp->fd_ofiles[indx];
if ((wfp = fd_getfile(fdp, dfd)) == NULL)
return (EBADF);
if (fp == wfp)
return (EBADF);
FILE_USE(wfp);
/*
* There are two cases of interest here.
*
* For ENODEV simply dup (dfd) to file descriptor
* (indx) and return.
*
* For ENXIO steal away the file structure from (dfd) and
* store it in (indx). (dfd) is effectively closed by
* this operation.
*
* Any other error code is just returned.
*/
switch (error) {
case ENODEV:
/*
* Check that the mode the file is being opened for is a
* subset of the mode of the existing descriptor.
*/
if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) {
FILE_UNUSE(wfp, p);
return (EACCES);
}
fdp->fd_ofiles[indx] = wfp;
fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
wfp->f_count++;
fd_used(fdp, indx);
FILE_UNUSE(wfp, p);
return (0);
case ENXIO:
/*
* Steal away the file pointer from dfd, and stuff it into indx.
*/
fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
fdp->fd_ofiles[dfd] = NULL;
fdp->fd_ofileflags[dfd] = 0;
/*
* Complete the clean up of the filedesc structure by
* recomputing the various hints.
*/
fd_used(fdp, indx);
fd_unused(fdp, dfd);
FILE_UNUSE(wfp, p);
return (0);
default:
FILE_UNUSE(wfp, p);
return (error);
}
/* NOTREACHED */
}
/*
* fcntl call which is being passed to the file's fs.
*/
int
fcntl_forfs(int fd, struct proc *p, int cmd, void *arg)
{
struct file *fp;
struct filedesc *fdp;
int error;
u_int size;
caddr_t data, memp;
#define STK_PARAMS 128
char stkbuf[STK_PARAMS];
/* fd's value was validated in sys_fcntl before calling this routine */
fdp = p->p_fd;
fp = fdp->fd_ofiles[fd];
if ((fp->f_flag & (FREAD | FWRITE)) == 0)
return (EBADF);
/*
* Interpret high order word to find amount of data to be
* copied to/from the user's address space.
*/
size = (size_t)F_PARAM_LEN(cmd);
if (size > F_PARAM_MAX)
return (EINVAL);
memp = NULL;
if (size > sizeof(stkbuf)) {
memp = (caddr_t)malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
data = memp;
} else
data = stkbuf;
if (cmd & F_FSIN) {
if (size) {
error = copyin(arg, data, size);
if (error) {
if (memp)
free(memp, M_IOCTLOPS);
return (error);
}
} else
*(caddr_t *)data = arg;
} else if ((cmd & F_FSOUT) && size)
/*
* Zero the buffer so the user always
* gets back something deterministic.
*/
memset(data, 0, size);
else if (cmd & F_FSVOID)
*(caddr_t *)data = arg;
error = (*fp->f_ops->fo_fcntl)(fp, cmd, data, p);
/*
* Copy any data to user, size was
* already set and checked above.
*/
if (error == 0 && (cmd & F_FSOUT) && size)
error = copyout(data, arg, size);
if (memp)
free(memp, M_IOCTLOPS);
return (error);
}
/*
* Close any files on exec?
*/
void
fdcloseexec(struct proc *p)
{
struct filedesc *fdp;
int fd;
fdunshare(p);
cwdunshare(p);
fdp = p->p_fd;
for (fd = 0; fd <= fdp->fd_lastfile; fd++)
if (fdp->fd_ofileflags[fd] & UF_EXCLOSE)
(void) fdrelease(p, fd);
}
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