common/syscall/open.c

	open.c revision d3e55dcdc881b833a707e39ae1e12d8d5d35ad2d
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

/*
 * Portions of this source code were derived from Berkeley 4.3 BSD
 * under license from the Regents of the University of California.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/param.h>
#include <sys/isa_defs.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/user.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/fcntl.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <sys/vfs.h>
#include <sys/file.h>
#include <sys/mode.h>
#include <sys/uio.h>
#include <sys/debug.h>
#include <c2/audit.h>
#include <sys/cmn_err.h>

/*
 * Common code for open()/openat() and creat().  Check permissions, allocate
 * an open file structure, and call the device open routine (if any).
 */

static int
copen(int startfd, char *fname, int filemode, int createmode)
{
    struct pathname pn;
    vnode_t *vp, *sdvp;
    file_t *fp, *startfp;
    enum vtype type;
    int error;
    int fd, dupfd;
    vnode_t *startvp;
    proc_t *p = curproc;
    uio_seg_t seg = UIO_USERSPACE;
    char *open_filename = fname;

    if (startfd == AT_FDCWD) {
        /*
         * Regular open()
         */
        startvp = NULL;
    } else {
        /*
         * We're here via openat()
         */
        char startchar;

        if (copyin(fname, &startchar, sizeof (char)))
            return (set_errno(EFAULT));

        /*
         * if startchar is / then startfd is ignored
         */
        if (startchar == '/')
            startvp = NULL;
        else {
            if ((startfp = getf(startfd)) == NULL)
                return (set_errno(EBADF));
            startvp = startfp->f_vnode;
            VN_HOLD(startvp);
            releasef(startfd);
        }
    }

    /*
     * Handle openattrdirat request
     */
    if (filemode & FXATTRDIROPEN) {
            if (audit_active)
                audit_setfsat_path(1);

        if (error = lookupnameat(fname, seg, FOLLOW,
            NULLVPP, &vp, startvp))
            return (set_errno(error));
        if (startvp) {
            VN_RELE(startvp);
            startvp = NULL;
        }

        startvp = vp;
    }

    /*
     * Do we need to go into extended attribute space?
     */
    if (filemode & (FXATTR|FXATTRDIROPEN)) {
        vattr_t vattr;

        /*
         * Make sure we have a valid request.
         * We must either have a real fd or AT_FDCWD
         */

        if (startfd != AT_FDCWD && startvp == NULL) {
            error = EINVAL;
            goto out;
        }

        if (error = pn_get(fname, UIO_USERSPACE, &pn)) {
            goto out;
        }

        if (startfd == AT_FDCWD && !(filemode & FXATTRDIROPEN)) {
            mutex_enter(&p->p_lock);
            startvp = PTOU(p)->u_cdir;
            VN_HOLD(startvp);
            mutex_exit(&p->p_lock);
        }

        /*
         * In order to access hidden attribute directory the
         * user must be able to stat() the file
         */

        vattr.va_mask = AT_ALL;
        if (error = VOP_GETATTR(startvp, &vattr, 0, CRED(), NULL)) {
            pn_free(&pn);
            goto out;
        }

        if ((startvp->v_vfsp->vfs_flag & VFS_XATTR) != 0 ||
            vfs_has_feature(startvp->v_vfsp, VFSFT_XVATTR)) {
            error = VOP_LOOKUP(startvp, "", &sdvp, &pn,
                LOOKUP_XATTR|CREATE_XATTR_DIR, rootvp, CRED(),
                NULL, NULL, NULL);
        } else {
            error = EINVAL;
        }

        /*
         * For openattrdirat use "." as filename to open
         * as part of vn_openat()
         */
        if (error == 0 && (filemode & FXATTRDIROPEN)) {
            open_filename = ".";
            seg = UIO_SYSSPACE;
        }

        pn_free(&pn);
        if (error != 0)
            goto out;

        VN_RELE(startvp);
        startvp = sdvp;
    }

    if ((filemode & (FREAD|FWRITE|FXATTRDIROPEN)) != 0) {
        if ((filemode & (FNONBLOCK|FNDELAY)) == (FNONBLOCK|FNDELAY))
            filemode &= ~FNDELAY;
        error = falloc((vnode_t *)NULL, filemode, &fp, &fd);
        if (error == 0) {
            if (audit_active)
                audit_setfsat_path(1);
            /*
             * Last arg is a don't-care term if
             * !(filemode & FCREAT).
             */

            error = vn_openat(open_filename, seg, filemode,
                (int)(createmode & MODEMASK),
                &vp, CRCREAT, PTOU(curproc)->u_cmask,
                startvp, fd);

            if (startvp != NULL)
                VN_RELE(startvp);
            if (error == 0) {
                if (audit_active)
                    audit_copen(fd, fp, vp);
                if ((vp->v_flag & VDUP) == 0) {
                    fp->f_vnode = vp;
                    mutex_exit(&fp->f_tlock);
                    /*
                     * We must now fill in the slot
                     * falloc reserved.
                     */
                    setf(fd, fp);
                    return (fd);
                } else {
                    /*
                     * Special handling for /dev/fd.
                     * Give up the file pointer
                     * and dup the indicated file descriptor
                     * (in v_rdev). This is ugly, but I've
                     * seen worse.
                     */
                    unfalloc(fp);
                    dupfd = getminor(vp->v_rdev);
                    type = vp->v_type;
                    mutex_enter(&vp->v_lock);
                    vp->v_flag &= ~VDUP;
                    mutex_exit(&vp->v_lock);
                    VN_RELE(vp);
                    if (type != VCHR)
                        return (set_errno(EINVAL));
                    if ((fp = getf(dupfd)) == NULL) {
                        setf(fd, NULL);
                        return (set_errno(EBADF));
                    }
                    mutex_enter(&fp->f_tlock);
                    fp->f_count++;
                    mutex_exit(&fp->f_tlock);
                    setf(fd, fp);
                    releasef(dupfd);
                }
                return (fd);
            } else {
                setf(fd, NULL);
                unfalloc(fp);
                return (set_errno(error));
            }
        }
    } else {
        error = EINVAL;
    }
out:
    if (startvp != NULL)
        VN_RELE(startvp);
    return (set_errno(error));
}

#define OPENMODE32(fmode)   ((int)((fmode)-FOPEN))
#define CREATMODE32     (FWRITE|FCREAT|FTRUNC)
#define OPENMODE64(fmode)   (OPENMODE32(fmode) | FOFFMAX)
#define OPENMODEATTRDIR     FXATTRDIROPEN
#define CREATMODE64     (CREATMODE32 | FOFFMAX)
#ifdef _LP64
#define OPENMODE(fmode)     OPENMODE64(fmode)
#define CREATMODE       CREATMODE64
#else
#define OPENMODE        OPENMODE32
#define CREATMODE       CREATMODE32
#endif

/*
 * Open a file.
 */
int
open(char *fname, int fmode, int cmode)
{
    return (copen(AT_FDCWD, fname, OPENMODE(fmode), cmode));
}

/*
 * Create a file.
 */
int
creat(char *fname, int cmode)
{
    return (copen(AT_FDCWD, fname, CREATMODE, cmode));
}

int
openat(int fd, char *path, int fmode, int cmode)
{
    return (copen(fd, path, OPENMODE(fmode), cmode));
}

#if defined(_ILP32) || defined(_SYSCALL32_IMPL)
/*
 * Open and Creat for large files in 32-bit environment. Sets the FOFFMAX flag.
 */
int
open64(char *fname, int fmode, int cmode)
{
    return (copen(AT_FDCWD, fname, OPENMODE64(fmode), cmode));
}

int
creat64(char *fname, int cmode)
{
    return (copen(AT_FDCWD, fname, CREATMODE64, cmode));
}

int
openat64(int fd, char *path, int fmode, int cmode)
{
    return (copen(fd, path, OPENMODE64(fmode), cmode));
}

#endif  /* _ILP32 || _SYSCALL32_IMPL */

#ifdef _SYSCALL32_IMPL
/*
 * Open and Creat for 32-bit compatibility on 64-bit kernel
 */
int
open32(char *fname, int fmode, int cmode)
{
    return (copen(AT_FDCWD, fname, OPENMODE32(fmode), cmode));
}

int
creat32(char *fname, int cmode)
{
    return (copen(AT_FDCWD, fname, CREATMODE32, cmode));
}

int
openat32(int fd, char *path, int fmode, int cmode)
{
    return (copen(fd, path, OPENMODE32(fmode), cmode));
}

#endif  /* _SYSCALL32_IMPL */

/*
 * Special interface to open hidden attribute directory.
 */
int
openattrdirat(int fd, char *fname)
{
    return (copen(fd, fname, OPENMODEATTRDIR, 0));
}