Begin splitting up namei into smaller pieces.
This commit is contained in:
dholland
parent
5fff5d2f6b
commit
40c09fbf2c
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@ -1,4 +1,4 @@
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/* $NetBSD: vfs_lookup.c,v 1.116 2009/06/29 05:00:14 dholland Exp $ */
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/* $NetBSD: vfs_lookup.c,v 1.117 2009/08/09 03:28:35 dholland Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1989, 1993
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@ -37,7 +37,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.116 2009/06/29 05:00:14 dholland Exp $");
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__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.117 2009/08/09 03:28:35 dholland Exp $");
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#include "opt_magiclinks.h"
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@ -216,25 +216,61 @@ symlink_magic(struct proc *p, char *cp, size_t *len)
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* if symbolic link, massage name in buffer and continue
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* }
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*/
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int
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namei(struct nameidata *ndp)
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{
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struct cwdinfo *cwdi; /* pointer to cwd state */
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char *cp; /* pointer into pathname argument */
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/*
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* Internal state for a namei operation.
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*/
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struct namei_state {
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struct nameidata *ndp;
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struct componentname *cnp;
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struct vnode *dp; /* the directory we are searching */
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struct iovec aiov; /* uio for reading symbolic links */
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struct lwp *l = curlwp; /* thread doing namei() */
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struct uio auio;
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int error;
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size_t linklen;
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struct componentname *cnp = &ndp->ni_cnd;
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};
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/*
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* Initialize the namei working state.
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*/
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static void
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namei_init(struct namei_state *state, struct nameidata *ndp)
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{
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state->ndp = ndp;
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state->cnp = &ndp->ni_cnd;
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state->dp = NULL;
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}
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/*
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* Clean up the working namei state, leaving things ready for return
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* from namei.
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*/
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static void
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namei_cleanup(struct namei_state *state)
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{
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KASSERT(state->cnp == &state->ndp->ni_cnd);
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//KASSERT(state->dp == NULL); // not yet
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/* nothing for now */
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(void)state;
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}
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//////////////////////////////
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/*
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* Start up namei. Early portion.
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*
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* This is divided from namei_start2 by the emul_retry: point.
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*/
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static void
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namei_start1(struct namei_state *state)
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{
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#ifdef DIAGNOSTIC
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if (!cnp->cn_cred)
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if (!state->cnp->cn_cred)
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panic("namei: bad cred/proc");
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if (cnp->cn_nameiop & (~OPMASK))
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if (state->cnp->cn_nameiop & (~OPMASK))
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panic("namei: nameiop contaminated with flags");
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if (cnp->cn_flags & OPMASK)
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if (state->cnp->cn_flags & OPMASK)
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panic("namei: flags contaminated with nameiops");
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#endif
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@ -242,9 +278,24 @@ namei(struct nameidata *ndp)
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* Get a buffer for the name to be translated, and copy the
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* name into the buffer.
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*/
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if ((cnp->cn_flags & HASBUF) == 0)
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cnp->cn_pnbuf = PNBUF_GET();
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emul_retry:
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if ((state->cnp->cn_flags & HASBUF) == 0)
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state->cnp->cn_pnbuf = PNBUF_GET();
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}
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/*
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* Start up namei. Copy the path, find the root dir and cwd, establish
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* the starting directory for lookup, and lock it.
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*/
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static int
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namei_start2(struct namei_state *state)
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{
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struct nameidata *ndp = state->ndp;
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struct componentname *cnp = state->cnp;
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struct cwdinfo *cwdi; /* pointer to cwd state */
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struct lwp *self = curlwp; /* thread doing namei() */
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int error;
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if (ndp->ni_segflg == UIO_SYSSPACE)
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error = copystr(ndp->ni_dirp, cnp->cn_pnbuf,
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MAXPATHLEN, &ndp->ni_pathlen);
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@ -268,12 +319,12 @@ namei(struct nameidata *ndp)
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/*
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* Get root directory for the translation.
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*/
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cwdi = l->l_proc->p_cwdi;
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cwdi = self->l_proc->p_cwdi;
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rw_enter(&cwdi->cwdi_lock, RW_READER);
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dp = cwdi->cwdi_rdir;
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if (dp == NULL)
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dp = rootvnode;
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ndp->ni_rootdir = dp;
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state->dp = cwdi->cwdi_rdir;
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if (state->dp == NULL)
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state->dp = rootvnode;
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ndp->ni_rootdir = state->dp;
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/*
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* Check if starting from root directory or current directory.
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@ -282,7 +333,7 @@ namei(struct nameidata *ndp)
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if (cnp->cn_flags & TRYEMULROOT) {
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if (cnp->cn_flags & EMULROOTSET) {
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/* Called from (eg) emul_find_interp() */
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dp = ndp->ni_erootdir;
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state->dp = ndp->ni_erootdir;
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} else {
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if (cwdi->cwdi_edir == NULL
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|| (cnp->cn_pnbuf[1] == '.'
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@ -290,22 +341,25 @@ namei(struct nameidata *ndp)
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&& cnp->cn_pnbuf[3] == '/')) {
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ndp->ni_erootdir = NULL;
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} else {
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dp = cwdi->cwdi_edir;
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ndp->ni_erootdir = dp;
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state->dp = cwdi->cwdi_edir;
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ndp->ni_erootdir = state->dp;
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}
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}
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} else {
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ndp->ni_erootdir = NULL;
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if (cnp->cn_flags & NOCHROOT)
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dp = ndp->ni_rootdir = rootvnode;
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state->dp = ndp->ni_rootdir = rootvnode;
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}
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} else {
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dp = cwdi->cwdi_cdir;
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state->dp = cwdi->cwdi_cdir;
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ndp->ni_erootdir = NULL;
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}
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VREF(dp);
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VREF(state->dp);
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rw_exit(&cwdi->cwdi_lock);
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/*
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* Ktrace it.
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*/
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if (ktrpoint(KTR_NAMEI)) {
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if (ndp->ni_erootdir != NULL) {
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/*
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@ -320,26 +374,161 @@ namei(struct nameidata *ndp)
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if (cnp->cn_flags & EMULROOTSET)
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emul_path = ndp->ni_next;
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else
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emul_path = l->l_proc->p_emul->e_path;
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emul_path = self->l_proc->p_emul->e_path;
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ktrnamei2(emul_path, strlen(emul_path),
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cnp->cn_pnbuf, ndp->ni_pathlen);
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} else
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ktrnamei(cnp->cn_pnbuf, ndp->ni_pathlen);
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}
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vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
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vn_lock(state->dp, LK_EXCLUSIVE | LK_RETRY);
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return 0;
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}
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/*
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* Undo namei_start: unlock and release the current lookup directory,
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* and discard the path buffer.
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*/
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static void
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namei_end(struct namei_state *state)
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{
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vput(state->dp);
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PNBUF_PUT(state->cnp->cn_pnbuf);
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//state->cnp->cn_pnbuf = NULL; // not yet (just in case) (XXX)
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}
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/*
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* Check for being at a symlink.
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*/
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static inline int
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namei_atsymlink(struct namei_state *state)
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{
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return (state->cnp->cn_flags & ISSYMLINK) != 0;
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}
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/*
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* Follow a symlink.
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*/
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static inline int
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namei_follow(struct namei_state *state)
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{
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struct nameidata *ndp = state->ndp;
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struct componentname *cnp = state->cnp;
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struct lwp *self = curlwp; /* thread doing namei() */
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struct iovec aiov; /* uio for reading symbolic links */
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struct uio auio;
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char *cp; /* pointer into pathname argument */
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size_t linklen;
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int error;
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if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
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return ELOOP;
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}
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if (ndp->ni_vp->v_mount->mnt_flag & MNT_SYMPERM) {
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error = VOP_ACCESS(ndp->ni_vp, VEXEC, cnp->cn_cred);
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if (error != 0)
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return error;
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}
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if (ndp->ni_pathlen > 1)
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cp = PNBUF_GET();
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else
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cp = cnp->cn_pnbuf;
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aiov.iov_base = cp;
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aiov.iov_len = MAXPATHLEN;
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auio.uio_iov = &aiov;
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auio.uio_iovcnt = 1;
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auio.uio_offset = 0;
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auio.uio_rw = UIO_READ;
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auio.uio_resid = MAXPATHLEN;
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UIO_SETUP_SYSSPACE(&auio);
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error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
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if (error) {
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badlink:
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if (ndp->ni_pathlen > 1)
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PNBUF_PUT(cp);
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return error;
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}
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linklen = MAXPATHLEN - auio.uio_resid;
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if (linklen == 0) {
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error = ENOENT;
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goto badlink;
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}
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/*
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* Do symlink substitution, if appropriate, and
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* check length for potential overflow.
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*/
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if ((vfs_magiclinks &&
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symlink_magic(self->l_proc, cp, &linklen)) ||
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(linklen + ndp->ni_pathlen >= MAXPATHLEN)) {
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error = ENAMETOOLONG;
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goto badlink;
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}
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if (ndp->ni_pathlen > 1) {
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memcpy(cp + linklen, ndp->ni_next, ndp->ni_pathlen);
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PNBUF_PUT(cnp->cn_pnbuf);
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cnp->cn_pnbuf = cp;
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} else
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cnp->cn_pnbuf[linklen] = '\0';
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ndp->ni_pathlen += linklen;
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vput(ndp->ni_vp);
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state->dp = ndp->ni_dvp;
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/*
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* Check if root directory should replace current directory.
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*/
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if (cnp->cn_pnbuf[0] == '/') {
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vput(state->dp);
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/* Keep absolute symbolic links inside emulation root */
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state->dp = ndp->ni_erootdir;
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if (state->dp == NULL || (cnp->cn_pnbuf[1] == '.'
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&& cnp->cn_pnbuf[2] == '.'
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&& cnp->cn_pnbuf[3] == '/')) {
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ndp->ni_erootdir = NULL;
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state->dp = ndp->ni_rootdir;
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}
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VREF(state->dp);
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vn_lock(state->dp, LK_EXCLUSIVE | LK_RETRY);
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}
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return 0;
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}
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//////////////////////////////
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static int
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do_namei(struct namei_state *state)
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{
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int error;
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struct nameidata *ndp = state->ndp;
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struct componentname *cnp = state->cnp;
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KASSERT(cnp == &ndp->ni_cnd);
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namei_start1(state);
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emul_retry:
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error = namei_start2(state);
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if (error) {
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return error;
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}
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/* Loop through symbolic links */
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for (;;) {
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if (!dp->v_mount) {
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if (!state->dp->v_mount) {
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/* Give up if the directory is no longer mounted */
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vput(dp);
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PNBUF_PUT(cnp->cn_pnbuf);
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namei_end(state);
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return (ENOENT);
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}
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cnp->cn_nameptr = cnp->cn_pnbuf;
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ndp->ni_startdir = dp;
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ndp->ni_startdir = state->dp;
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error = lookup(ndp);
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if (error != 0) {
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/* XXX this should use namei_end() */
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if (ndp->ni_dvp) {
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vput(ndp->ni_dvp);
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}
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@ -355,103 +544,56 @@ namei(struct nameidata *ndp)
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/*
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* Check for symbolic link
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*/
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if ((cnp->cn_flags & ISSYMLINK) == 0) {
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if ((cnp->cn_flags & LOCKPARENT) == 0 && ndp->ni_dvp) {
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if (ndp->ni_dvp == ndp->ni_vp) {
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vrele(ndp->ni_dvp);
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} else {
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vput(ndp->ni_dvp);
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}
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}
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if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) {
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if (namei_atsymlink(state)) {
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error = namei_follow(state);
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if (error) {
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KASSERT(ndp->ni_dvp != ndp->ni_vp);
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vput(ndp->ni_dvp);
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vput(ndp->ni_vp);
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ndp->ni_vp = NULL;
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PNBUF_PUT(cnp->cn_pnbuf);
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#if defined(DIAGNOSTIC)
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cnp->cn_pnbuf = NULL;
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#endif /* defined(DIAGNOSTIC) */
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} else {
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cnp->cn_flags |= HASBUF;
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return error;
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}
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return (0);
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}
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if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
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error = ELOOP;
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else {
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break;
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}
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if (ndp->ni_vp->v_mount->mnt_flag & MNT_SYMPERM) {
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error = VOP_ACCESS(ndp->ni_vp, VEXEC, cnp->cn_cred);
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if (error != 0)
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break;
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}
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if (ndp->ni_pathlen > 1)
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cp = PNBUF_GET();
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else
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cp = cnp->cn_pnbuf;
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aiov.iov_base = cp;
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aiov.iov_len = MAXPATHLEN;
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auio.uio_iov = &aiov;
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auio.uio_iovcnt = 1;
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auio.uio_offset = 0;
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auio.uio_rw = UIO_READ;
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auio.uio_resid = MAXPATHLEN;
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UIO_SETUP_SYSSPACE(&auio);
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error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
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if (error) {
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badlink:
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if (ndp->ni_pathlen > 1)
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PNBUF_PUT(cp);
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break;
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}
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linklen = MAXPATHLEN - auio.uio_resid;
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if (linklen == 0) {
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error = ENOENT;
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goto badlink;
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}
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/*
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* Do symlink substitution, if appropriate, and
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* check length for potential overflow.
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*/
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if ((vfs_magiclinks &&
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symlink_magic(l->l_proc, cp, &linklen)) ||
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(linklen + ndp->ni_pathlen >= MAXPATHLEN)) {
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error = ENAMETOOLONG;
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goto badlink;
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}
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if (ndp->ni_pathlen > 1) {
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memcpy(cp + linklen, ndp->ni_next, ndp->ni_pathlen);
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PNBUF_PUT(cnp->cn_pnbuf);
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cnp->cn_pnbuf = cp;
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} else
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cnp->cn_pnbuf[linklen] = '\0';
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ndp->ni_pathlen += linklen;
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vput(ndp->ni_vp);
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dp = ndp->ni_dvp;
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/*
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* Check if root directory should replace current directory.
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*/
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if (cnp->cn_pnbuf[0] == '/') {
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vput(dp);
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/* Keep absolute symbolic links inside emulation root */
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dp = ndp->ni_erootdir;
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if (dp == NULL || (cnp->cn_pnbuf[1] == '.'
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&& cnp->cn_pnbuf[2] == '.'
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&& cnp->cn_pnbuf[3] == '/')) {
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ndp->ni_erootdir = NULL;
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dp = ndp->ni_rootdir;
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}
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VREF(dp);
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vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
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}
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}
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/* Failed to process a symbolic link */
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KASSERT(ndp->ni_dvp != ndp->ni_vp);
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vput(ndp->ni_dvp);
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vput(ndp->ni_vp);
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ndp->ni_vp = NULL;
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PNBUF_PUT(cnp->cn_pnbuf);
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return (error);
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/*
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* Done
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*/
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if ((cnp->cn_flags & LOCKPARENT) == 0 && ndp->ni_dvp) {
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if (ndp->ni_dvp == ndp->ni_vp) {
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vrele(ndp->ni_dvp);
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} else {
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vput(ndp->ni_dvp);
|
||||
}
|
||||
}
|
||||
if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) {
|
||||
PNBUF_PUT(cnp->cn_pnbuf);
|
||||
#if defined(DIAGNOSTIC)
|
||||
cnp->cn_pnbuf = NULL;
|
||||
#endif /* defined(DIAGNOSTIC) */
|
||||
} else {
|
||||
cnp->cn_flags |= HASBUF;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int
|
||||
namei(struct nameidata *ndp)
|
||||
{
|
||||
struct namei_state state;
|
||||
int error;
|
||||
|
||||
namei_init(&state, ndp);
|
||||
error = do_namei(&state);
|
||||
namei_cleanup(&state);
|
||||
|
||||
return error;
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
|
|||
Loading…
Reference in New Issue