/*
* Takes ni_vp and ni_dvp non-NULL. Returns with *new_dp set to the location
* at which to start a lookup with a resolved path, and all other iocounts dropped.
*/
int
lookup_handle_symlink(struct nameidata *ndp, vnode_t *new_dp, vfs_context_t ctx)
{
int error;
char *cp; /* pointer into pathname argument */
uio_t auio;
char uio_buf[ UIO_SIZEOF(1) ];
int need_newpathbuf;
u_int linklen;
struct componentname *cnp = &ndp->ni_cnd;
vnode_t dp;
char *tmppn;
#if CONFIG_VFS_FUNNEL
if ((cnp->cn_flags & FSNODELOCKHELD)) {
cnp->cn_flags &= ~FSNODELOCKHELD;
unlock_fsnode(ndp->ni_dvp, NULL);
}
#endif /* CONFIG_VFS_FUNNEL */
if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
return ELOOP;
}
#if CONFIG_MACF
if ((error = mac_vnode_check_readlink(ctx, ndp->ni_vp)) != 0)
return error;
#endif /* MAC */
if (ndp->ni_pathlen > 1 || !(cnp->cn_flags & HASBUF))
need_newpathbuf = 1;
else
need_newpathbuf = 0;
if (need_newpathbuf) {
MALLOC_ZONE(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
if (cp == NULL) {
return ENOMEM;
}
} else {
cp = cnp->cn_pnbuf;
}
auio = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ, &uio_buf[0], sizeof(uio_buf));
uio_addiov(auio, CAST_USER_ADDR_T(cp), MAXPATHLEN);
error = VNOP_READLINK(ndp->ni_vp, auio, ctx);
if (error) {
if (need_newpathbuf)
FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
return error;
}
/*
* Safe to set unsigned with a [larger] signed type here
* because 0 <= uio_resid <= MAXPATHLEN and MAXPATHLEN
* is only 1024.
*/
linklen = MAXPATHLEN - (u_int)uio_resid(auio);
if (linklen + ndp->ni_pathlen > MAXPATHLEN) {
if (need_newpathbuf)
FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
return ENAMETOOLONG;
}
if (need_newpathbuf) {
long len = cnp->cn_pnlen;
tmppn = cnp->cn_pnbuf;
bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
cnp->cn_pnbuf = cp;
cnp->cn_pnlen = MAXPATHLEN;
if ( (cnp->cn_flags & HASBUF) )
FREE_ZONE(tmppn, len, M_NAMEI);
else
cnp->cn_flags |= HASBUF;
} else
cnp->cn_pnbuf[linklen] = '\0';
ndp->ni_pathlen += linklen;
cnp->cn_nameptr = cnp->cn_pnbuf;
/*
* starting point for 'relative'
* symbolic link path
*/
dp = ndp->ni_dvp;
/*
* get rid of references returned via 'lookup'
*/
vnode_put(ndp->ni_vp);
vnode_put(ndp->ni_dvp); /* ALWAYS have a dvp for a symlink */
ndp->ni_vp = NULLVP;
ndp->ni_dvp = NULLVP;
/*
* Check if symbolic link restarts us at the root
*/
if (*(cnp->cn_nameptr) == '/') {
while (*(cnp->cn_nameptr) == '/') {
cnp->cn_nameptr++;
ndp->ni_pathlen--;
}
if ((dp = ndp->ni_rootdir) == NULLVP) {
return ENOENT;
}
}
*new_dp = dp;
return 0;
}
/*
* Convert a pathname into a pointer to a locked inode.
*
* The FOLLOW flag is set when symbolic links are to be followed
* when they occur at the end of the name translation process.
* Symbolic links are always followed for all other pathname
* components other than the last.
*
* The segflg defines whether the name is to be copied from user
* space or kernel space.
*
* Overall outline of namei:
*
* copy in name
* get starting directory
* while (!done && !error) {
* call lookup to search path.
* if symbolic link, massage name in buffer and continue
* }
*
* Returns: 0 Success
* ENOENT No such file or directory
* ELOOP Too many levels of symbolic links
* ENAMETOOLONG Filename too long
* copyinstr:EFAULT Bad address
* copyinstr:ENAMETOOLONG Filename too long
* lookup:EBADF Bad file descriptor
* lookup:EROFS
* lookup:EACCES
* lookup:EPERM
* lookup:ERECYCLE vnode was recycled from underneath us in lookup.
* This means we should re-drive lookup from this point.
* lookup: ???
* VNOP_READLINK:???
*/
int
namei(struct nameidata *ndp)
{
struct filedesc *fdp; /* pointer to file descriptor state */
char *cp; /* pointer into pathname argument */
struct vnode *dp; /* the directory we are searching */
struct vnode *usedvp = ndp->ni_dvp; /* store pointer to vp in case we must loop due to
heavy vnode pressure */
u_long cnpflags = ndp->ni_cnd.cn_flags; /* store in case we have to restore after loop */
uio_t auio;
int error;
struct componentname *cnp = &ndp->ni_cnd;
vfs_context_t ctx = cnp->cn_context;
proc_t p = vfs_context_proc(ctx);
/* XXX ut should be from context */
uthread_t ut = (struct uthread *)get_bsdthread_info(current_thread());
char *tmppn;
char uio_buf[ UIO_SIZEOF(1) ];
#if DIAGNOSTIC
if (!vfs_context_ucred(ctx) || !p)
panic ("namei: bad cred/proc");
if (cnp->cn_nameiop & (~OPMASK))
panic ("namei: nameiop contaminated with flags");
if (cnp->cn_flags & OPMASK)
panic ("namei: flags contaminated with nameiops");
#endif
fdp = p->p_fd;
vnode_recycled:
/*
* Get a buffer for the name to be translated, and copy the
* name into the buffer.
*/
if ((cnp->cn_flags & HASBUF) == 0) {
cnp->cn_pnbuf = ndp->ni_pathbuf;
cnp->cn_pnlen = PATHBUFLEN;
}
#if LP64_DEBUG
if (IS_VALID_UIO_SEGFLG(ndp->ni_segflg) == 0) {
panic("%s :%d - invalid ni_segflg\n", __FILE__, __LINE__);
}
#endif /* LP64_DEBUG */
retry_copy:
if (UIO_SEG_IS_USER_SPACE(ndp->ni_segflg)) {
error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
cnp->cn_pnlen, (size_t *)&ndp->ni_pathlen);
} else {
error = copystr(CAST_DOWN(void *, ndp->ni_dirp), cnp->cn_pnbuf,
cnp->cn_pnlen, (size_t *)&ndp->ni_pathlen);
}
if (error == ENAMETOOLONG && !(cnp->cn_flags & HASBUF)) {
MALLOC_ZONE(cnp->cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
if (cnp->cn_pnbuf == NULL) {
error = ENOMEM;
goto error_out;
}
cnp->cn_flags |= HASBUF;
cnp->cn_pnlen = MAXPATHLEN;
goto retry_copy;
}
if (error)
goto error_out;
#if CONFIG_VOLFS
/*
* Check for legacy volfs style pathnames.
*
* For compatibility reasons we currently allow these paths,
* but future versions of the OS may not support them.
*/
if (ndp->ni_pathlen >= VOLFS_MIN_PATH_LEN &&
cnp->cn_pnbuf[0] == '/' &&
cnp->cn_pnbuf[1] == '.' &&
cnp->cn_pnbuf[2] == 'v' &&
cnp->cn_pnbuf[3] == 'o' &&
cnp->cn_pnbuf[4] == 'l' &&
cnp->cn_pnbuf[5] == '/' ) {
char * realpath;
int realpath_err;
/* Attempt to resolve a legacy volfs style pathname. */
MALLOC_ZONE(realpath, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
if (realpath) {
if ((realpath_err= vfs_getrealpath(&cnp->cn_pnbuf[6], realpath, MAXPATHLEN, ctx))) {
FREE_ZONE(realpath, MAXPATHLEN, M_NAMEI);
if (realpath_err == ENOSPC){
error = ENAMETOOLONG;
goto error_out;
}
} else {
if (cnp->cn_flags & HASBUF) {
FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
}
cnp->cn_pnbuf = realpath;
cnp->cn_pnlen = MAXPATHLEN;
ndp->ni_pathlen = strlen(realpath) + 1;
cnp->cn_flags |= HASBUF | CN_VOLFSPATH;
}
}
}
#endif /* CONFIG_VOLFS */
/* If we are auditing the kernel pathname, save the user pathname */
if (cnp->cn_flags & AUDITVNPATH1)
AUDIT_ARG(upath, ut->uu_cdir, cnp->cn_pnbuf, ARG_UPATH1);
if (cnp->cn_flags & AUDITVNPATH2)
AUDIT_ARG(upath, ut->uu_cdir, cnp->cn_pnbuf, ARG_UPATH2);
/*
* Do not allow empty pathnames
*/
if (*cnp->cn_pnbuf == '\0') {
error = ENOENT;
goto error_out;
}
ndp->ni_loopcnt = 0;
/*
* determine the starting point for the translation.
*/
if ((ndp->ni_rootdir = fdp->fd_rdir) == NULLVP) {
if ( !(fdp->fd_flags & FD_CHROOT))
ndp->ni_rootdir = rootvnode;
}
cnp->cn_nameptr = cnp->cn_pnbuf;
ndp->ni_usedvp = NULLVP;
if (*(cnp->cn_nameptr) == '/') {
while (*(cnp->cn_nameptr) == '/') {
cnp->cn_nameptr++;
ndp->ni_pathlen--;
}
dp = ndp->ni_rootdir;
} else if (cnp->cn_flags & USEDVP) {
dp = ndp->ni_dvp;
ndp->ni_usedvp = dp;
} else
dp = vfs_context_cwd(ctx);
if (dp == NULLVP || (dp->v_lflag & VL_DEAD)) {
error = ENOENT;
goto error_out;
}
ndp->ni_dvp = NULLVP;
ndp->ni_vp = NULLVP;
for (;;) {
int need_newpathbuf;
int linklen;
ndp->ni_startdir = dp;
if ( (error = lookup(ndp)) ) {
goto error_out;
}
/*
* Check for symbolic link
*/
if ((cnp->cn_flags & ISSYMLINK) == 0) {
return (0);
}
if ((cnp->cn_flags & FSNODELOCKHELD)) {
cnp->cn_flags &= ~FSNODELOCKHELD;
unlock_fsnode(ndp->ni_dvp, NULL);
}
if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
error = ELOOP;
break;
}
#if CONFIG_MACF
if ((error = mac_vnode_check_readlink(ctx, ndp->ni_vp)) != 0)
break;
#endif /* MAC */
if (ndp->ni_pathlen > 1 || !(cnp->cn_flags & HASBUF))
need_newpathbuf = 1;
else
need_newpathbuf = 0;
if (need_newpathbuf) {
MALLOC_ZONE(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
if (cp == NULL) {
error = ENOMEM;
break;
}
} else {
cp = cnp->cn_pnbuf;
}
auio = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ, &uio_buf[0], sizeof(uio_buf));
uio_addiov(auio, CAST_USER_ADDR_T(cp), MAXPATHLEN);
error = VNOP_READLINK(ndp->ni_vp, auio, ctx);
if (error) {
if (need_newpathbuf)
FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
break;
}
// LP64todo - fix this
linklen = MAXPATHLEN - uio_resid(auio);
if (linklen + ndp->ni_pathlen > MAXPATHLEN) {
if (need_newpathbuf)
FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
error = ENAMETOOLONG;
break;
}
if (need_newpathbuf) {
long len = cnp->cn_pnlen;
tmppn = cnp->cn_pnbuf;
bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
cnp->cn_pnbuf = cp;
cnp->cn_pnlen = MAXPATHLEN;
if ( (cnp->cn_flags & HASBUF) )
FREE_ZONE(tmppn, len, M_NAMEI);
else
cnp->cn_flags |= HASBUF;
} else
cnp->cn_pnbuf[linklen] = '\0';
ndp->ni_pathlen += linklen;
cnp->cn_nameptr = cnp->cn_pnbuf;
/*
* starting point for 'relative'
* symbolic link path
*/
dp = ndp->ni_dvp;
/*
* get rid of references returned via 'lookup'
*/
vnode_put(ndp->ni_vp);
vnode_put(ndp->ni_dvp);
ndp->ni_vp = NULLVP;
ndp->ni_dvp = NULLVP;
/*
* Check if symbolic link restarts us at the root
*/
if (*(cnp->cn_nameptr) == '/') {
while (*(cnp->cn_nameptr) == '/') {
cnp->cn_nameptr++;
ndp->ni_pathlen--;
}
if ((dp = ndp->ni_rootdir) == NULLVP) {
error = ENOENT;
goto error_out;
}
}
}
/*
* only come here if we fail to handle a SYMLINK...
* if either ni_dvp or ni_vp is non-NULL, then
* we need to drop the iocount that was picked
* up in the lookup routine
*/
if (ndp->ni_dvp)
vnode_put(ndp->ni_dvp);
if (ndp->ni_vp)
vnode_put(ndp->ni_vp);
error_out:
if ( (cnp->cn_flags & HASBUF) ) {
cnp->cn_flags &= ~HASBUF;
FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
}
cnp->cn_pnbuf = NULL;
ndp->ni_vp = NULLVP;
if (error == ERECYCLE){
/* vnode was recycled underneath us. re-drive lookup to start at
the beginning again, since recycling invalidated last lookup*/
ndp->ni_cnd.cn_flags = cnpflags;
ndp->ni_dvp = usedvp;
goto vnode_recycled;
}
return (error);
}
