common/syscall/stat.c

/*
 * 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 (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*  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.
 */

/*
 * Get file attribute information through a file name or a file descriptor.
 */

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

/*
 * Get the vp to be stated and the cred to be used for the call
 * to VOP_GETATTR
 */

static int
cstatat_getvp(int fd, char *name, int follow, vnode_t **vp, cred_t **cred)
{
    vnode_t *startvp;
    file_t *fp;
    int error;
    cred_t *cr;
    int estale_retry = 0;

    *vp = NULL;

    /*
     * Only return EFAULT for fstatat when fd == AT_FDCWD && name == NULL
     */

    if (fd == AT_FDCWD) {
        startvp = NULL;
        cr = CRED();
        crhold(cr);
    } else {
        char startchar;

        if (copyin(name, &startchar, sizeof (char)))
            return (EFAULT);
        if (startchar != '/') {
            if ((fp = getf(fd)) == NULL) {
                return (EBADF);
            }
            startvp = fp->f_vnode;
            cr = fp->f_cred;
            crhold(cr);
            VN_HOLD(startvp);
            releasef(fd);
        } else {
            startvp = NULL;
            cr = CRED();
            crhold(cr);
        }
    }
    *cred = cr;

    if (AU_AUDITING() && startvp != NULL)
        audit_setfsat_path(1);

lookup:
    if (error = lookupnameat(name, UIO_USERSPACE, follow, NULLVPP,
        vp, startvp)) {
        if ((error == ESTALE) &&
            fs_need_estale_retry(estale_retry++))
            goto lookup;
        if (startvp != NULL)
            VN_RELE(startvp);
        crfree(cr);
        return (error);
    }
    if (startvp != NULL)
        VN_RELE(startvp);

    return (0);
}

/*
 * Native syscall interfaces:
 *
 * N-bit kernel, N-bit applications, N-bit file offsets
 */

static int cstatat(int, char *, struct stat *, int, int);
static int cstat(vnode_t *vp, struct stat *, int, cred_t *);

/*
 * fstat can and should be fast, do an inline implementation here.
 */
#define FSTAT_BODY(fd, sb, statfn)              \
    {                           \
        file_t *fp;                 \
        int error;                  \
                                \
        if (fd == AT_FDCWD)             \
            return (set_errno(EFAULT));     \
        if ((fp = getf(fd)) == NULL)            \
            return (set_errno(EBADF));      \
        error = statfn(fp->f_vnode, sb, 0, fp->f_cred); \
        releasef(fd);                   \
        if (error)                  \
            return (set_errno(error));      \
        return (0);                 \
    }

int
fstat(int fd, struct stat *sb)
{
    FSTAT_BODY(fd, sb, cstat)
}

int
fstatat(int fd, char *name, struct stat *sb, int flags)
{
    int followflag;
    int csflags;

    if (name == NULL)
        return (fstat(fd, sb));

    followflag = (flags & AT_SYMLINK_NOFOLLOW);
    csflags = (flags & _AT_TRIGGER ? ATTR_TRIGGER : 0);
    if (followflag == 0)
        csflags |= ATTR_REAL;   /* flag for procfs lookups */

    return (cstatat(fd, name, sb, followflag, csflags));
}

int
stat(char *name, struct stat *sb)
{
    return (fstatat(AT_FDCWD, name, sb, 0));
}

int
lstat(char *name, struct stat *sb)
{
    return (fstatat(AT_FDCWD, name, sb, AT_SYMLINK_NOFOLLOW));
}

/*
 * Common code for stat(), lstat(), and fstat().
 * (32-bit kernel, 32-bit applications, 32-bit files)
 * (64-bit kernel, 64-bit applications, 64-bit files)
 */
static int
cstat(vnode_t *vp, struct stat *ubp, int flag, cred_t *cr)
{
    struct vfssw *vswp;
    struct stat sb;
    vattr_t vattr;
    int error;

    vattr.va_mask = AT_STAT | AT_NBLOCKS | AT_BLKSIZE | AT_SIZE;
    if ((error = VOP_GETATTR(vp, &vattr, flag, cr, NULL)) != 0)
        return (error);
#ifdef  _ILP32
    /*
     * (32-bit kernel, 32-bit applications, 32-bit files)
     * NOTE: 32-bit kernel maintains a 64-bit unsigend va_size.
     *
     * st_size of devices (VBLK and VCHR special files) is a special case.
     * POSIX does not define size behavior for special files, so the
     * following Solaris specific behavior is not a violation. Solaris
     * returns the size of the device.
     *
     * For compatibility with 32-bit programs which happen to do stat() on
     * a (mknod) bigger than 2GB we suppress the large file EOVERFLOW and
     * instead we return the value MAXOFF32_T (LONG_MAX).
     *
     * 32-bit applications that care about the size of devices should be
     * built 64-bit or use a large file interface (lfcompile(5) or lf64(5)).
     */
    if ((vattr.va_size > MAXOFF32_T) &&
        ((vp->v_type == VBLK) || (vp->v_type == VCHR))) {
        /* OVERFLOW | UNKNOWN_SIZE */
        vattr.va_size = MAXOFF32_T;
    }
#endif  /* _ILP32 */
    if (vattr.va_size > MAXOFF_T || vattr.va_nblocks > LONG_MAX ||
        vattr.va_nodeid > ULONG_MAX)
        return (EOVERFLOW);

    bzero(&sb, sizeof (sb));
    sb.st_dev = vattr.va_fsid;
    sb.st_ino = (ino_t)vattr.va_nodeid;
    sb.st_mode = VTTOIF(vattr.va_type) | vattr.va_mode;
    sb.st_nlink = vattr.va_nlink;
    sb.st_uid = vattr.va_uid;
    sb.st_gid = vattr.va_gid;
    sb.st_rdev = vattr.va_rdev;
    sb.st_size = (off_t)vattr.va_size;
    sb.st_atim = vattr.va_atime;
    sb.st_mtim = vattr.va_mtime;
    sb.st_ctim = vattr.va_ctime;
    sb.st_blksize = vattr.va_blksize;
    sb.st_blocks = (blkcnt_t)vattr.va_nblocks;
    if (vp->v_vfsp != NULL) {
        vswp = &vfssw[vp->v_vfsp->vfs_fstype];
        if (vswp->vsw_name && *vswp->vsw_name)
            (void) strcpy(sb.st_fstype, vswp->vsw_name);
    }
    if (copyout(&sb, ubp, sizeof (sb)))
        return (EFAULT);
    return (0);
}

static int
cstatat(int fd, char *name, struct stat *sb, int follow, int flags)
{
    vnode_t *vp;
    int error;
    cred_t *cred;
    int link_follow;
    int estale_retry = 0;

    link_follow = (follow == AT_SYMLINK_NOFOLLOW) ? NO_FOLLOW : FOLLOW;
lookup:
    if (error = cstatat_getvp(fd, name, link_follow, &vp, &cred))
        return (set_errno(error));
    error = cstat(vp, sb, flags, cred);
    crfree(cred);
    VN_RELE(vp);
    if (error != 0) {
        if (error == ESTALE &&
            fs_need_estale_retry(estale_retry++))
            goto lookup;
        return (set_errno(error));
    }
    return (0);
}

#if defined(_SYSCALL32_IMPL)

/*
 * 64-bit kernel, 32-bit applications, 32-bit file offsets
 */
static int cstatat32(int, char *, struct stat32 *, int, int);
static int cstat32(vnode_t *, struct stat32 *, int, cred_t *);

int
fstat32(int fd, struct stat32 *sb)
{
    FSTAT_BODY(fd, sb, cstat32)
}

int
fstatat32(int fd, char *name, struct stat32 *sb, int flags)
{
    int followflag;
    int csflags;

    if (name == NULL)
        return (fstat32(fd, sb));

    followflag = (flags & AT_SYMLINK_NOFOLLOW);
    csflags = (flags & _AT_TRIGGER ? ATTR_TRIGGER : 0);
    if (followflag == 0)
        csflags |= ATTR_REAL;   /* flag for procfs lookups */

    return (cstatat32(fd, name, sb, followflag, csflags));
}

int
stat32(char *name, struct stat32 *sb)
{
    return (fstatat32(AT_FDCWD, name, sb, 0));
}

int
lstat32(char *name, struct stat32 *sb)
{
    return (fstatat32(AT_FDCWD, name, sb, AT_SYMLINK_NOFOLLOW));
}

static int
cstat32(vnode_t *vp, struct stat32 *ubp, int flag, struct cred *cr)
{
    struct vfssw *vswp;
    struct stat32 sb;
    vattr_t vattr;
    int error;
    dev32_t st_dev, st_rdev;

    vattr.va_mask = AT_STAT | AT_NBLOCKS | AT_BLKSIZE | AT_SIZE;
    if (error = VOP_GETATTR(vp, &vattr, flag, cr, NULL))
        return (error);

    /* devices are a special case, see comments in cstat */
    if ((vattr.va_size > MAXOFF32_T) &&
        ((vp->v_type == VBLK) || (vp->v_type == VCHR))) {
        /* OVERFLOW | UNKNOWN_SIZE */
        vattr.va_size = MAXOFF32_T;
    }

    /* check for large values */
    if (!cmpldev(&st_dev, vattr.va_fsid) ||
        !cmpldev(&st_rdev, vattr.va_rdev) ||
        vattr.va_size > MAXOFF32_T ||
        vattr.va_nblocks > INT32_MAX ||
        vattr.va_nodeid > UINT32_MAX ||
        TIMESPEC_OVERFLOW(&(vattr.va_atime)) ||
        TIMESPEC_OVERFLOW(&(vattr.va_mtime)) ||
        TIMESPEC_OVERFLOW(&(vattr.va_ctime)))
        return (EOVERFLOW);

    bzero(&sb, sizeof (sb));
    sb.st_dev = st_dev;
    sb.st_ino = (ino32_t)vattr.va_nodeid;
    sb.st_mode = VTTOIF(vattr.va_type) | vattr.va_mode;
    sb.st_nlink = vattr.va_nlink;
    sb.st_uid = vattr.va_uid;
    sb.st_gid = vattr.va_gid;
    sb.st_rdev = st_rdev;
    sb.st_size = (off32_t)vattr.va_size;
    TIMESPEC_TO_TIMESPEC32(&(sb.st_atim), &(vattr.va_atime));
    TIMESPEC_TO_TIMESPEC32(&(sb.st_mtim), &(vattr.va_mtime));
    TIMESPEC_TO_TIMESPEC32(&(sb.st_ctim), &(vattr.va_ctime));
    sb.st_blksize = vattr.va_blksize;
    sb.st_blocks = (blkcnt32_t)vattr.va_nblocks;
    if (vp->v_vfsp != NULL) {
        vswp = &vfssw[vp->v_vfsp->vfs_fstype];
        if (vswp->vsw_name && *vswp->vsw_name)
            (void) strcpy(sb.st_fstype, vswp->vsw_name);
    }
    if (copyout(&sb, ubp, sizeof (sb)))
        return (EFAULT);
    return (0);
}

static int
cstatat32(int fd, char *name, struct stat32 *sb, int follow, int flags)
{
    vnode_t *vp;
    int error;
    cred_t *cred;
    int link_follow;
    int estale_retry = 0;

    link_follow = (follow == AT_SYMLINK_NOFOLLOW) ? NO_FOLLOW : FOLLOW;
lookup:
    if (error = cstatat_getvp(fd, name, link_follow, &vp, &cred))
        return (set_errno(error));
    error = cstat32(vp, sb, flags, cred);
    crfree(cred);
    VN_RELE(vp);
    if (error != 0) {
        if (error == ESTALE &&
            fs_need_estale_retry(estale_retry++))
            goto lookup;
        return (set_errno(error));
    }
    return (0);
}

#endif  /* _SYSCALL32_IMPL */

#if defined(_ILP32)

/*
 * 32-bit kernel, 32-bit applications, 64-bit file offsets.
 *
 * These routines are implemented differently on 64-bit kernels.
 */
static int cstatat64(int, char *, struct stat64 *, int, int);
static int cstat64(vnode_t *, struct stat64 *, int, cred_t *);

int
fstat64(int fd, struct stat64 *sb)
{
    FSTAT_BODY(fd, sb, cstat64)
}

int
fstatat64(int fd, char *name, struct stat64 *sb, int flags)
{
    int followflag;
    int csflags;

    if (name == NULL)
        return (fstat64(fd, sb));

    followflag = (flags & AT_SYMLINK_NOFOLLOW);
    csflags = (flags & _AT_TRIGGER ? ATTR_TRIGGER : 0);
    if (followflag == 0)
        csflags |= ATTR_REAL;   /* flag for procfs lookups */

    return (cstatat64(fd, name, sb, followflag, csflags));
}

int
stat64(char *name, struct stat64 *sb)
{
    return (fstatat64(AT_FDCWD, name, sb, 0));
}

int
lstat64(char *name, struct stat64 *sb)
{
    return (fstatat64(AT_FDCWD, name, sb, AT_SYMLINK_NOFOLLOW));
}

static int
cstat64(vnode_t *vp, struct stat64 *ubp, int flag, cred_t *cr)
{
    struct vfssw *vswp;
    struct stat64 lsb;
    vattr_t vattr;
    int error;

    vattr.va_mask = AT_STAT | AT_NBLOCKS | AT_BLKSIZE | AT_SIZE;
    if (error = VOP_GETATTR(vp, &vattr, flag, cr, NULL))
        return (error);

    bzero(&lsb, sizeof (lsb));
    lsb.st_dev = vattr.va_fsid;
    lsb.st_ino = vattr.va_nodeid;
    lsb.st_mode = VTTOIF(vattr.va_type) | vattr.va_mode;
    lsb.st_nlink = vattr.va_nlink;
    lsb.st_uid = vattr.va_uid;
    lsb.st_gid = vattr.va_gid;
    lsb.st_rdev = vattr.va_rdev;
    lsb.st_size = vattr.va_size;
    lsb.st_atim = vattr.va_atime;
    lsb.st_mtim = vattr.va_mtime;
    lsb.st_ctim = vattr.va_ctime;
    lsb.st_blksize = vattr.va_blksize;
    lsb.st_blocks = vattr.va_nblocks;
    if (vp->v_vfsp != NULL) {
        vswp = &vfssw[vp->v_vfsp->vfs_fstype];
        if (vswp->vsw_name && *vswp->vsw_name)
            (void) strcpy(lsb.st_fstype, vswp->vsw_name);
    }
    if (copyout(&lsb, ubp, sizeof (lsb)))
        return (EFAULT);
    return (0);
}

static int
cstatat64(int fd, char *name, struct stat64 *sb, int follow, int flags)
{
    vnode_t *vp;
    int error;
    cred_t *cred;
    int link_follow;
    int estale_retry = 0;

    link_follow = (follow == AT_SYMLINK_NOFOLLOW) ? NO_FOLLOW : FOLLOW;
lookup:
    if (error = cstatat_getvp(fd, name, link_follow, &vp, &cred))
        return (set_errno(error));
    error = cstat64(vp, sb, flags, cred);
    crfree(cred);
    VN_RELE(vp);
    if (error != 0) {
        if (error == ESTALE &&
            fs_need_estale_retry(estale_retry++))
            goto lookup;
        return (set_errno(error));
    }
    return (0);
}

#endif  /* _ILP32 */

#if defined(_SYSCALL32_IMPL)

/*
 * 64-bit kernel, 32-bit applications, 64-bit file offsets.
 *
 * We'd really like to call the "native" stat calls for these ones,
 * but the problem is that the 64-bit ABI defines the 'stat64' structure
 * differently from the way the 32-bit ABI defines it.
 */

static int cstatat64_32(int, char *, struct stat64_32 *, int, int);
static int cstat64_32(vnode_t *, struct stat64_32 *, int, cred_t *);

int
fstat64_32(int fd, struct stat64_32 *sb)
{
    FSTAT_BODY(fd, sb, cstat64_32)
}

int
fstatat64_32(int fd, char *name, struct stat64_32 *sb, int flags)
{
    int followflag;
    int csflags;

    if (name == NULL)
        return (fstat64_32(fd, sb));

    followflag = (flags & AT_SYMLINK_NOFOLLOW);
    csflags = (flags & _AT_TRIGGER ? ATTR_TRIGGER : 0);
    if (followflag == 0)
        csflags |= ATTR_REAL;   /* flag for procfs lookups */

    return (cstatat64_32(fd, name, sb, followflag, csflags));
}

int
stat64_32(char *name, struct stat64_32 *sb)
{
    return (fstatat64_32(AT_FDCWD, name, sb, 0));
}

int
lstat64_32(char *name, struct stat64_32 *sb)
{
    return (fstatat64_32(AT_FDCWD, name, sb, AT_SYMLINK_NOFOLLOW));
}

static int
cstat64_32(vnode_t *vp, struct stat64_32 *ubp, int flag, cred_t *cr)
{
    struct vfssw *vswp;
    struct stat64_32 lsb;
    vattr_t vattr;
    int error;
    dev32_t st_dev, st_rdev;

    vattr.va_mask = AT_STAT | AT_NBLOCKS | AT_BLKSIZE | AT_SIZE;
    if (error = VOP_GETATTR(vp, &vattr, flag, cr, NULL))
        return (error);

    if (!cmpldev(&st_dev, vattr.va_fsid) ||
        !cmpldev(&st_rdev, vattr.va_rdev) ||
        TIMESPEC_OVERFLOW(&(vattr.va_atime)) ||
        TIMESPEC_OVERFLOW(&(vattr.va_mtime)) ||
        TIMESPEC_OVERFLOW(&(vattr.va_ctime)))
        return (EOVERFLOW);

    bzero(&lsb, sizeof (lsb));
    lsb.st_dev = st_dev;
    lsb.st_ino = vattr.va_nodeid;
    lsb.st_mode = VTTOIF(vattr.va_type) | vattr.va_mode;
    lsb.st_nlink = vattr.va_nlink;
    lsb.st_uid = vattr.va_uid;
    lsb.st_gid = vattr.va_gid;
    lsb.st_rdev = st_rdev;
    lsb.st_size = vattr.va_size;
    TIMESPEC_TO_TIMESPEC32(&(lsb.st_atim), &(vattr.va_atime));
    TIMESPEC_TO_TIMESPEC32(&(lsb.st_mtim), &(vattr.va_mtime));
    TIMESPEC_TO_TIMESPEC32(&(lsb.st_ctim), &(vattr.va_ctime));
    lsb.st_blksize = vattr.va_blksize;
    lsb.st_blocks = vattr.va_nblocks;
    if (vp->v_vfsp != NULL) {
        vswp = &vfssw[vp->v_vfsp->vfs_fstype];
        if (vswp->vsw_name && *vswp->vsw_name)
            (void) strcpy(lsb.st_fstype, vswp->vsw_name);
    }
    if (copyout(&lsb, ubp, sizeof (lsb)))
        return (EFAULT);
    return (0);
}

static int
cstatat64_32(int fd, char *name, struct stat64_32 *sb, int follow, int flags)
{
    vnode_t  *vp;
    int error;
    cred_t *cred;
    int link_follow;
    int estale_retry = 0;

    link_follow = (follow == AT_SYMLINK_NOFOLLOW) ? NO_FOLLOW : FOLLOW;
lookup:
    if (error = cstatat_getvp(fd, name, link_follow, &vp, &cred))
        return (set_errno(error));
    error = cstat64_32(vp, sb, flags, cred);
    crfree(cred);
    VN_RELE(vp);
    if (error != 0) {
        if (error == ESTALE &&
            fs_need_estale_retry(estale_retry++))
            goto lookup;
        return (set_errno(error));
    }
    return (0);
}

#endif /* _SYSCALL32_IMPL */