Backout the getcwd changes, a more comprehensive effort will be needed.
This commit is contained in:
Poul-Henning Kamp
parent
a29355a07b
commit
cc34e37e5b
@ -37,25 +37,432 @@
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "opt_compat.h"
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#include "opt_mac.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/namei.h>
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#include <sys/filedesc.h>
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#include <sys/kernel.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/syscallsubr.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/uio.h>
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#include <sys/mac.h>
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#include <sys/malloc.h>
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#include <sys/dirent.h>
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#include <ufs/ufs/dir.h> /* XXX only for DIRBLKSIZ */
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#include <machine/../linux/linux.h>
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#include <machine/../linux/linux_proto.h>
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#include <compat/linux/linux_util.h>
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static int
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linux_getcwd_scandir(struct vnode **, struct vnode **,
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char **, char *, struct thread *);
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static int
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linux_getcwd_common(struct vnode *, struct vnode *,
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char **, char *, int, int, struct thread *);
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#define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
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/*
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* Vnode variable naming conventions in this file:
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*
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* rvp: the current root we're aiming towards.
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* lvp, *lvpp: the "lower" vnode
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* uvp, *uvpp: the "upper" vnode.
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*
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* Since all the vnodes we're dealing with are directories, and the
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* lookups are going *up* in the filesystem rather than *down*, the
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* usual "pvp" (parent) or "dvp" (directory) naming conventions are
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* too confusing.
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*/
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/*
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* XXX Will infinite loop in certain cases if a directory read reliably
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* returns EINVAL on last block.
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* XXX is EINVAL the right thing to return if a directory is malformed?
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*/
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/*
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* XXX Untested vs. mount -o union; probably does the wrong thing.
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*/
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/*
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* Find parent vnode of *lvpp, return in *uvpp
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*
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* If we care about the name, scan it looking for name of directory
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* entry pointing at lvp.
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*
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* Place the name in the buffer which starts at bufp, immediately
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* before *bpp, and move bpp backwards to point at the start of it.
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*
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* On entry, *lvpp is a locked vnode reference; on exit, it is vput and NULL'ed
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* On exit, *uvpp is either NULL or is a locked vnode reference.
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*/
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static int
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linux_getcwd_scandir(lvpp, uvpp, bpp, bufp, td)
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struct vnode **lvpp;
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struct vnode **uvpp;
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char **bpp;
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char *bufp;
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struct thread *td;
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{
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int error = 0;
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int eofflag;
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off_t off;
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int tries;
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struct uio uio;
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struct iovec iov;
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char *dirbuf = NULL;
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int dirbuflen;
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ino_t fileno;
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struct vattr va;
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struct vnode *uvp = NULL;
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struct vnode *lvp = *lvpp;
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struct componentname cn;
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int len, reclen;
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tries = 0;
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/*
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* If we want the filename, get some info we need while the
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* current directory is still locked.
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*/
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if (bufp != NULL) {
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error = VOP_GETATTR(lvp, &va, td->td_ucred, td);
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if (error) {
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vput(lvp);
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*lvpp = NULL;
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*uvpp = NULL;
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return error;
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}
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}
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/*
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* Ok, we have to do it the hard way..
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* Next, get parent vnode using lookup of ..
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*/
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cn.cn_nameiop = LOOKUP;
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cn.cn_flags = ISLASTCN | ISDOTDOT | RDONLY;
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cn.cn_thread = td;
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cn.cn_cred = td->td_ucred;
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cn.cn_pnbuf = NULL;
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cn.cn_nameptr = "..";
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cn.cn_namelen = 2;
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cn.cn_consume = 0;
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/*
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* At this point, lvp is locked and will be unlocked by the lookup.
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* On successful return, *uvpp will be locked
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*/
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error = VOP_LOOKUP(lvp, uvpp, &cn);
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if (error) {
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vput(lvp);
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*lvpp = NULL;
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*uvpp = NULL;
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return error;
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}
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uvp = *uvpp;
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/* If we don't care about the pathname, we're done */
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if (bufp == NULL) {
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vrele(lvp);
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*lvpp = NULL;
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return 0;
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}
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fileno = va.va_fileid;
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dirbuflen = DIRBLKSIZ;
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if (dirbuflen < va.va_blocksize)
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dirbuflen = va.va_blocksize;
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dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
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#if 0
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unionread:
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#endif
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off = 0;
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do {
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/* call VOP_READDIR of parent */
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iov.iov_base = dirbuf;
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iov.iov_len = dirbuflen;
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uio.uio_iov = &iov;
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uio.uio_iovcnt = 1;
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uio.uio_offset = off;
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uio.uio_resid = dirbuflen;
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uio.uio_segflg = UIO_SYSSPACE;
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uio.uio_rw = UIO_READ;
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uio.uio_td = td;
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eofflag = 0;
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#ifdef MAC
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error = mac_check_vnode_readdir(td->td_ucred, uvp);
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if (error == 0)
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#endif /* MAC */
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error = VOP_READDIR(uvp, &uio, td->td_ucred, &eofflag,
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0, 0);
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off = uio.uio_offset;
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/*
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* Try again if NFS tosses its cookies.
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* XXX this can still loop forever if the directory is busted
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* such that the second or subsequent page of it always
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* returns EINVAL
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*/
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if ((error == EINVAL) && (tries < 3)) {
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off = 0;
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tries++;
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continue; /* once more, with feeling */
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}
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if (!error) {
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char *cpos;
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struct dirent *dp;
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cpos = dirbuf;
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tries = 0;
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/* scan directory page looking for matching vnode */
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for (len = (dirbuflen - uio.uio_resid); len > 0; len -= reclen) {
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dp = (struct dirent *) cpos;
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reclen = dp->d_reclen;
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/* check for malformed directory.. */
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if (reclen < DIRENT_MINSIZE) {
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error = EINVAL;
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goto out;
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}
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/*
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* XXX should perhaps do VOP_LOOKUP to
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* check that we got back to the right place,
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* but getting the locking games for that
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* right would be heinous.
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*/
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if ((dp->d_type != DT_WHT) &&
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(dp->d_fileno == fileno)) {
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char *bp = *bpp;
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bp -= dp->d_namlen;
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if (bp <= bufp) {
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error = ERANGE;
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goto out;
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}
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bcopy(dp->d_name, bp, dp->d_namlen);
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error = 0;
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*bpp = bp;
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goto out;
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}
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cpos += reclen;
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}
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}
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} while (!eofflag);
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error = ENOENT;
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out:
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vrele(lvp);
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*lvpp = NULL;
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free(dirbuf, M_TEMP);
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return error;
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}
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/*
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* common routine shared by sys___getcwd() and linux_vn_isunder()
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*/
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#define GETCWD_CHECK_ACCESS 0x0001
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static int
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linux_getcwd_common (lvp, rvp, bpp, bufp, limit, flags, td)
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struct vnode *lvp;
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struct vnode *rvp;
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char **bpp;
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char *bufp;
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int limit;
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int flags;
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struct thread *td;
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{
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struct filedesc *fdp = td->td_proc->p_fd;
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struct vnode *uvp = NULL;
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char *bp = NULL;
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int error;
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int perms = VEXEC;
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if (rvp == NULL) {
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rvp = fdp->fd_rdir;
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if (rvp == NULL)
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rvp = rootvnode;
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}
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VREF(rvp);
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VREF(lvp);
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/*
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* Error handling invariant:
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* Before a `goto out':
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* lvp is either NULL, or locked and held.
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* uvp is either NULL, or locked and held.
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*/
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error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
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if (error) {
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vrele(lvp);
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lvp = NULL;
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goto out;
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}
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if (bufp)
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bp = *bpp;
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/*
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* this loop will terminate when one of the following happens:
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* - we hit the root
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* - getdirentries or lookup fails
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* - we run out of space in the buffer.
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*/
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if (lvp == rvp) {
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if (bp)
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*(--bp) = '/';
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goto out;
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}
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do {
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if (lvp->v_type != VDIR) {
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error = ENOTDIR;
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goto out;
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}
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/*
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* access check here is optional, depending on
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* whether or not caller cares.
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*/
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if (flags & GETCWD_CHECK_ACCESS) {
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error = VOP_ACCESS(lvp, perms, td->td_ucred, td);
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if (error)
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goto out;
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perms = VEXEC|VREAD;
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}
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/*
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* step up if we're a covered vnode..
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*/
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while (lvp->v_vflag & VV_ROOT) {
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struct vnode *tvp;
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if (lvp == rvp)
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goto out;
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tvp = lvp;
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lvp = lvp->v_mount->mnt_vnodecovered;
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vput(tvp);
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/*
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* hodie natus est radici frater
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*/
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if (lvp == NULL) {
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error = ENOENT;
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goto out;
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}
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VREF(lvp);
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error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
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if (error != 0) {
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vrele(lvp);
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lvp = NULL;
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goto out;
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}
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}
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error = linux_getcwd_scandir(&lvp, &uvp, &bp, bufp, td);
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if (error)
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goto out;
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#if DIAGNOSTIC
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if (lvp != NULL)
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panic("getcwd: oops, forgot to null lvp");
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if (bufp && (bp <= bufp)) {
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panic("getcwd: oops, went back too far");
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}
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#endif
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if (bp)
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*(--bp) = '/';
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lvp = uvp;
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uvp = NULL;
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limit--;
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} while ((lvp != rvp) && (limit > 0));
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out:
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if (bpp)
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*bpp = bp;
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if (uvp)
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vput(uvp);
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if (lvp)
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vput(lvp);
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vrele(rvp);
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return error;
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}
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/*
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* Find pathname of process's current directory.
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*
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* Use vfs vnode-to-name reverse cache; if that fails, fall back
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* to reading directory contents. Use the common routines in vfs_cache.c.
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* to reading directory contents.
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*/
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int
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linux_getcwd(struct thread *td, struct linux_getcwd_args *args)
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{
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return (kern___getcwd (td, args->buf, UIO_USERSPACE, args->bufsize));
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caddr_t bp, bend, path;
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int error, len, lenused;
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#ifdef DEBUG
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printf("Linux-emul(%ld): getcwd(%p, %ld)\n", (long)td->td_proc->p_pid,
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args->buf, (long)args->bufsize);
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#endif
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len = args->bufsize;
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if (len > MAXPATHLEN*4)
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len = MAXPATHLEN*4;
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else if (len < 2)
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return ERANGE;
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path = (char *)malloc(len, M_TEMP, M_WAITOK);
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error = kern___getcwd(td, path, UIO_SYSSPACE, len);
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if (!error) {
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lenused = strlen(path) + 1;
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if (lenused <= args->bufsize) {
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td->td_retval[0] = lenused;
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error = copyout(path, args->buf, lenused);
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}
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else
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error = ERANGE;
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} else {
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bp = &path[len];
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bend = bp;
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*(--bp) = '\0';
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/*
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* 5th argument here is "max number of vnodes to traverse".
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* Since each entry takes up at least 2 bytes in the output buffer,
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* limit it to N/2 vnodes for an N byte buffer.
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*/
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error = linux_getcwd_common (td->td_proc->p_fd->fd_cdir, NULL,
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&bp, path, len/2, GETCWD_CHECK_ACCESS, td);
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if (error)
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goto out;
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lenused = bend - bp;
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td->td_retval[0] = lenused;
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/* put the result into user buffer */
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error = copyout(bp, args->buf, lenused);
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}
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out:
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free(path, M_TEMP);
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return (error);
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}
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@ -52,8 +52,6 @@
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#include <sys/proc.h>
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#include <sys/filedesc.h>
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#include <sys/fnv_hash.h>
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#include <ufs/ufs/dir.h> /* XXX only for DIRBLKSIZ */
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#include <sys/dirent.h>
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/*
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* This structure describes the elements in the cache of recent
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@ -703,9 +701,6 @@ struct __getcwd_args {
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static int disablecwd;
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SYSCTL_INT(_debug, OID_AUTO, disablecwd, CTLFLAG_RW, &disablecwd, 0,
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"Disable the getcwd syscall");
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static int disable_cached_getcwd;
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SYSCTL_INT (_debug, OID_AUTO, disable_cached_getcwd, CTLFLAG_RW,
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&disable_cached_getcwd, 0, "Disable getcwd using vfs vnode cache");
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/* Various statistics for the getcwd syscall */
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static u_long numcwdcalls; STATNODE(CTLFLAG_RD, numcwdcalls, &numcwdcalls);
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@ -713,68 +708,20 @@ static u_long numcwdfail1; STATNODE(CTLFLAG_RD, numcwdfail1, &numcwdfail1);
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static u_long numcwdfail2; STATNODE(CTLFLAG_RD, numcwdfail2, &numcwdfail2);
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static u_long numcwdfail3; STATNODE(CTLFLAG_RD, numcwdfail3, &numcwdfail3);
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static u_long numcwdfail4; STATNODE(CTLFLAG_RD, numcwdfail4, &numcwdfail4);
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static u_long numcwdtraverse; STATNODE(CTLFLAG_RD, numcwdtraverse, &numcwdtraverse);
|
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static u_long numcwdfound; STATNODE(CTLFLAG_RD, numcwdfound, &numcwdfound);
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|
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#define GETCWD_CHECK_ACCESS 0x0001
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#define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
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|
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static int
|
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kern___getcwd_cached(struct thread *td, u_char *buf, enum uio_seg bufseg,
|
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u_int buflen);
|
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static int
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kern___getcwd_traverse(struct vnode *lvp, struct vnode *rvp, char **bpp,
|
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char *bufp, int limit, int flags, struct thread *td);
|
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static int
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kern___getcwd_scandir(struct vnode **lvpp, struct vnode **uvpp,
|
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char **bpp, char *bufp, struct thread *td);
|
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|
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/* Implementation of the getcwd syscall */
|
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int
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__getcwd(td, uap)
|
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struct thread *td;
|
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struct __getcwd_args *uap;
|
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{
|
||||
|
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return (kern___getcwd(td, uap->buf, UIO_USERSPACE, uap->buflen));
|
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}
|
||||
|
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/*
|
||||
* this part mostly from linux_getcwd. use the original kern___getcwd()
|
||||
* routine first, which uses the vfs vnode-to-name reverse cache. If
|
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* that fails, use the routines originally from linux_getcwd.c to
|
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* traverse the directory contents (much slower!)
|
||||
*/
|
||||
int
|
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kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg,
|
||||
u_int buflen)
|
||||
{
|
||||
int error;
|
||||
char *bp, *bend;
|
||||
|
||||
if (disablecwd)
|
||||
return (ENODEV);
|
||||
|
||||
if (kern___getcwd_cached (td, buf, bufseg, buflen) == 0)
|
||||
return 0;
|
||||
|
||||
bp = &buf[buflen];
|
||||
bend = bp;
|
||||
*(--bp) = '\0';
|
||||
error = kern___getcwd_traverse (td->td_proc->p_fd->fd_cdir, NULL, &bp,
|
||||
buf, buflen / 2, GETCWD_CHECK_ACCESS, td);
|
||||
if (!error) {
|
||||
if (bufseg == UIO_USERSPACE)
|
||||
error = copyout (bp, buf, bend - bp);
|
||||
/* linux_getcwd has this -- needed? */
|
||||
td->td_retval[0] = bend - bp;
|
||||
}
|
||||
return error;
|
||||
}
|
||||
|
||||
int
|
||||
kern___getcwd_cached (struct thread *td, u_char *buf, enum uio_seg bufseg,
|
||||
u_int buflen)
|
||||
kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen)
|
||||
{
|
||||
char *bp, *tmpbuf;
|
||||
int error, i, slash_prefixed;
|
||||
@ -783,7 +730,7 @@ kern___getcwd_cached (struct thread *td, u_char *buf, enum uio_seg bufseg,
|
||||
struct vnode *vp;
|
||||
|
||||
numcwdcalls++;
|
||||
if (disable_cached_getcwd)
|
||||
if (disablecwd)
|
||||
return (ENODEV);
|
||||
if (buflen < 2)
|
||||
return (EINVAL);
|
||||
@ -863,325 +810,6 @@ kern___getcwd_cached (struct thread *td, u_char *buf, enum uio_seg bufseg,
|
||||
return (error);
|
||||
}
|
||||
|
||||
/*
|
||||
* Vnode variable naming conventions in this file:
|
||||
*
|
||||
* rvp: the current root we're aiming towards.
|
||||
* lvp, *lvpp: the "lower" vnode
|
||||
* uvp, *uvpp: the "upper" vnode.
|
||||
*
|
||||
* Since all the vnodes we're dealing with are directories, and the
|
||||
* lookups are going *up* in the filesystem rather than *down*, the
|
||||
* usual "pvp" (parent) or "dvp" (directory) naming conventions are
|
||||
* too confusing.
|
||||
*/
|
||||
|
||||
/*
|
||||
* XXX Will infinite loop in certain cases if a directory read reliably
|
||||
* returns EINVAL on last block.
|
||||
* XXX is EINVAL the right thing to return if a directory is malformed?
|
||||
*/
|
||||
|
||||
/*
|
||||
* XXX Untested vs. mount -o union; probably does the wrong thing.
|
||||
*/
|
||||
|
||||
int
|
||||
kern___getcwd_traverse (struct vnode *lvp, struct vnode *rvp, char **bpp,
|
||||
char *bufp, int limit, int flags, struct thread *td)
|
||||
{
|
||||
struct filedesc *fdp = td->td_proc->p_fd;
|
||||
struct vnode *uvp = NULL;
|
||||
char *bp = NULL;
|
||||
int error;
|
||||
int perms = VEXEC;
|
||||
|
||||
numcwdtraverse++;
|
||||
|
||||
if (rvp == NULL) {
|
||||
rvp = fdp->fd_rdir;
|
||||
if (rvp == NULL)
|
||||
rvp = rootvnode;
|
||||
}
|
||||
|
||||
VREF(rvp);
|
||||
VREF(lvp);
|
||||
|
||||
/*
|
||||
* Error handling invariant:
|
||||
* Before a `goto out':
|
||||
* lvp is either NULL, or locked and held.
|
||||
* uvp is either NULL, or locked and held.
|
||||
*/
|
||||
|
||||
error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
|
||||
if (error) {
|
||||
vrele(lvp);
|
||||
lvp = NULL;
|
||||
goto out;
|
||||
}
|
||||
if (bufp)
|
||||
bp = *bpp;
|
||||
/*
|
||||
* this loop will terminate when one of the following happens:
|
||||
* - we hit the root
|
||||
* - getdirentries or lookup fails
|
||||
* - we run out of space in the buffer.
|
||||
*/
|
||||
if (lvp == rvp) {
|
||||
if (bp)
|
||||
*(--bp) = '/';
|
||||
goto out;
|
||||
}
|
||||
do {
|
||||
if (lvp->v_type != VDIR) {
|
||||
error = ENOTDIR;
|
||||
goto out;
|
||||
}
|
||||
|
||||
/*
|
||||
* access check here is optional, depending on
|
||||
* whether or not caller cares.
|
||||
*/
|
||||
if (flags & GETCWD_CHECK_ACCESS) {
|
||||
error = VOP_ACCESS(lvp, perms, td->td_ucred, td);
|
||||
if (error)
|
||||
goto out;
|
||||
perms = VEXEC|VREAD;
|
||||
}
|
||||
|
||||
/*
|
||||
* step up if we're a covered vnode..
|
||||
*/
|
||||
while (lvp->v_vflag & VV_ROOT) {
|
||||
struct vnode *tvp;
|
||||
|
||||
if (lvp == rvp)
|
||||
goto out;
|
||||
|
||||
tvp = lvp;
|
||||
lvp = lvp->v_mount->mnt_vnodecovered;
|
||||
vput(tvp);
|
||||
/*
|
||||
* hodie natus est radici frater
|
||||
*/
|
||||
if (lvp == NULL) {
|
||||
error = ENOENT;
|
||||
goto out;
|
||||
}
|
||||
VREF(lvp);
|
||||
error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY, td);
|
||||
if (error != 0) {
|
||||
vrele(lvp);
|
||||
lvp = NULL;
|
||||
goto out;
|
||||
}
|
||||
}
|
||||
error = kern___getcwd_scandir(&lvp, &uvp, &bp, bufp, td);
|
||||
if (error)
|
||||
goto out;
|
||||
#if DIAGNOSTIC
|
||||
if (lvp != NULL)
|
||||
panic("getcwd: oops, forgot to null lvp");
|
||||
if (bufp && (bp <= bufp)) {
|
||||
panic("getcwd: oops, went back too far");
|
||||
}
|
||||
#endif
|
||||
if (bp)
|
||||
*(--bp) = '/';
|
||||
lvp = uvp;
|
||||
uvp = NULL;
|
||||
limit--;
|
||||
} while ((lvp != rvp) && (limit > 0));
|
||||
|
||||
out:
|
||||
if (bpp)
|
||||
*bpp = bp;
|
||||
if (uvp)
|
||||
vput(uvp);
|
||||
if (lvp)
|
||||
vput(lvp);
|
||||
vrele(rvp);
|
||||
return error;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Find parent vnode of *lvpp, return in *uvpp
|
||||
*
|
||||
* If we care about the name, scan it looking for name of directory
|
||||
* entry pointing at lvp.
|
||||
*
|
||||
* Place the name in the buffer which starts at bufp, immediately
|
||||
* before *bpp, and move bpp backwards to point at the start of it.
|
||||
*
|
||||
* On entry, *lvpp is a locked vnode reference; on exit, it is vput and NULL'ed
|
||||
* On exit, *uvpp is either NULL or is a locked vnode reference.
|
||||
*/
|
||||
static int
|
||||
kern___getcwd_scandir (struct vnode **lvpp, struct vnode **uvpp,
|
||||
char **bpp, char *bufp, struct thread *td)
|
||||
{
|
||||
int error = 0;
|
||||
int eofflag;
|
||||
off_t off;
|
||||
int tries;
|
||||
struct uio uio;
|
||||
struct iovec iov;
|
||||
char *dirbuf = NULL;
|
||||
int dirbuflen;
|
||||
ino_t fileno;
|
||||
struct vattr va;
|
||||
struct vnode *uvp = NULL;
|
||||
struct vnode *lvp = *lvpp;
|
||||
struct componentname cn;
|
||||
int len, reclen;
|
||||
tries = 0;
|
||||
|
||||
/*
|
||||
* If we want the filename, get some info we need while the
|
||||
* current directory is still locked.
|
||||
*/
|
||||
if (bufp != NULL) {
|
||||
error = VOP_GETATTR(lvp, &va, td->td_ucred, td);
|
||||
if (error) {
|
||||
vput(lvp);
|
||||
*lvpp = NULL;
|
||||
*uvpp = NULL;
|
||||
return error;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Ok, we have to do it the hard way..
|
||||
* Next, get parent vnode using lookup of ..
|
||||
*/
|
||||
cn.cn_nameiop = LOOKUP;
|
||||
cn.cn_flags = ISLASTCN | ISDOTDOT | RDONLY;
|
||||
cn.cn_thread = td;
|
||||
cn.cn_cred = td->td_ucred;
|
||||
cn.cn_pnbuf = NULL;
|
||||
cn.cn_nameptr = "..";
|
||||
cn.cn_namelen = 2;
|
||||
cn.cn_consume = 0;
|
||||
|
||||
/*
|
||||
* At this point, lvp is locked and will be unlocked by the lookup.
|
||||
* On successful return, *uvpp will be locked
|
||||
*/
|
||||
error = VOP_LOOKUP(lvp, uvpp, &cn);
|
||||
if (error) {
|
||||
vput(lvp);
|
||||
*lvpp = NULL;
|
||||
*uvpp = NULL;
|
||||
return error;
|
||||
}
|
||||
uvp = *uvpp;
|
||||
|
||||
/* If we don't care about the pathname, we're done */
|
||||
if (bufp == NULL) {
|
||||
vrele(lvp);
|
||||
*lvpp = NULL;
|
||||
return 0;
|
||||
}
|
||||
|
||||
fileno = va.va_fileid;
|
||||
|
||||
dirbuflen = DIRBLKSIZ;
|
||||
if (dirbuflen < va.va_blocksize)
|
||||
dirbuflen = va.va_blocksize;
|
||||
dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
|
||||
|
||||
#if 0
|
||||
unionread:
|
||||
#endif
|
||||
off = 0;
|
||||
do {
|
||||
/* call VOP_READDIR of parent */
|
||||
iov.iov_base = dirbuf;
|
||||
iov.iov_len = dirbuflen;
|
||||
|
||||
uio.uio_iov = &iov;
|
||||
uio.uio_iovcnt = 1;
|
||||
uio.uio_offset = off;
|
||||
uio.uio_resid = dirbuflen;
|
||||
uio.uio_segflg = UIO_SYSSPACE;
|
||||
uio.uio_rw = UIO_READ;
|
||||
uio.uio_td = td;
|
||||
|
||||
eofflag = 0;
|
||||
|
||||
#ifdef MAC
|
||||
error = mac_check_vnode_readdir(td->td_ucred, uvp);
|
||||
if (error == 0)
|
||||
#endif /* MAC */
|
||||
error = VOP_READDIR(uvp, &uio, td->td_ucred, &eofflag,
|
||||
0, 0);
|
||||
|
||||
off = uio.uio_offset;
|
||||
|
||||
/*
|
||||
* Try again if NFS tosses its cookies.
|
||||
* XXX this can still loop forever if the directory is busted
|
||||
* such that the second or subsequent page of it always
|
||||
* returns EINVAL
|
||||
*/
|
||||
if ((error == EINVAL) && (tries < 3)) {
|
||||
off = 0;
|
||||
tries++;
|
||||
continue; /* once more, with feeling */
|
||||
}
|
||||
|
||||
if (!error) {
|
||||
char *cpos;
|
||||
struct dirent *dp;
|
||||
|
||||
cpos = dirbuf;
|
||||
tries = 0;
|
||||
|
||||
/* scan directory page looking for matching vnode */
|
||||
for (len = (dirbuflen - uio.uio_resid); len > 0; len -= reclen) {
|
||||
dp = (struct dirent *) cpos;
|
||||
reclen = dp->d_reclen;
|
||||
|
||||
/* check for malformed directory.. */
|
||||
if (reclen < DIRENT_MINSIZE) {
|
||||
error = EINVAL;
|
||||
goto out;
|
||||
}
|
||||
/*
|
||||
* XXX should perhaps do VOP_LOOKUP to
|
||||
* check that we got back to the right place,
|
||||
* but getting the locking games for that
|
||||
* right would be heinous.
|
||||
*/
|
||||
if ((dp->d_type != DT_WHT) &&
|
||||
(dp->d_fileno == fileno)) {
|
||||
char *bp = *bpp;
|
||||
bp -= dp->d_namlen;
|
||||
|
||||
if (bp <= bufp) {
|
||||
error = ERANGE;
|
||||
goto out;
|
||||
}
|
||||
bcopy(dp->d_name, bp, dp->d_namlen);
|
||||
error = 0;
|
||||
*bpp = bp;
|
||||
goto out;
|
||||
}
|
||||
cpos += reclen;
|
||||
}
|
||||
}
|
||||
} while (!eofflag);
|
||||
error = ENOENT;
|
||||
|
||||
out:
|
||||
vrele(lvp);
|
||||
*lvpp = NULL;
|
||||
free(dirbuf, M_TEMP);
|
||||
return error;
|
||||
}
|
||||
|
||||
/*
|
||||
* Thus begins the fullpath magic.
|
||||
*/
|
||||
|
||||
Loading…
Reference in New Issue
Block a user