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NetBSD/dist/am-utils/amd/readdir.c
christos b689db021c from ftp.am-utils.org
2005-04-23 18:07:47 +00:00

501 lines
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/* $NetBSD: readdir.c,v 1.1.1.2 2005/04/23 18:09:29 christos Exp $ */
/*
* Copyright (c) 1997-2005 Erez Zadok
* Copyright (c) 1990 Jan-Simon Pendry
* Copyright (c) 1990 Imperial College of Science, Technology & Medicine
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry at Imperial College, London.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgment:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
* Id: readdir.c,v 1.5 2005/03/21 00:16:53 ezk Exp
*
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <am_defs.h>
#include <amd.h>
/****************************************************************************
*** MACROS ***
****************************************************************************/
#define DOT_DOT_COOKIE (u_int) 1
#define MAX_CHAIN 2048
/****************************************************************************
*** FORWARD DEFINITIONS ***
****************************************************************************/
static int key_already_in_chain(char *keyname, const nfsentry *chain);
static nfsentry *make_entry_chain(am_node *mp, const nfsentry *current_chain, int fully_browsable);
static int amfs_readdir_browsable(am_node *mp, nfscookie cookie, nfsdirlist *dp, nfsentry *ep, u_int count, int fully_browsable);
/****************************************************************************
*** FUNCTIONS ***
****************************************************************************/
/*
* Was: NEW_TOPLVL_READDIR
* Search a chain for an entry with some name.
* -Erez Zadok <ezk@cs.columbia.edu>
*/
static int
key_already_in_chain(char *keyname, const nfsentry *chain)
{
const nfsentry *tmpchain = chain;
while (tmpchain) {
if (keyname && tmpchain->ne_name && STREQ(keyname, tmpchain->ne_name))
return 1;
tmpchain = tmpchain->ne_nextentry;
}
return 0;
}
/*
* Create a chain of entries which are not linked.
* -Erez Zadok <ezk@cs.columbia.edu>
*/
static nfsentry *
make_entry_chain(am_node *mp, const nfsentry *current_chain, int fully_browsable)
{
static u_int last_cookie = (u_int) 2; /* monotonically increasing */
static nfsentry chain[MAX_CHAIN];
static int max_entries = MAX_CHAIN;
char *key;
int num_entries = 0, i;
u_int preflen = 0;
nfsentry *retval = (nfsentry *) NULL;
mntfs *mf;
mnt_map *mmp;
if (!mp) {
plog(XLOG_DEBUG, "make_entry_chain: mp is (NULL)");
return retval;
}
mf = mp->am_mnt;
if (!mf) {
plog(XLOG_DEBUG, "make_entry_chain: mp->am_mnt is (NULL)");
return retval;
}
mmp = (mnt_map *) mf->mf_private;
if (!mmp) {
plog(XLOG_DEBUG, "make_entry_chain: mp->am_mnt->mf_private is (NULL)");
return retval;
}
if (mp->am_pref)
preflen = strlen(mp->am_pref);
/* iterate over keys */
for (i = 0; i < NKVHASH; i++) {
kv *k;
for (k = mmp->kvhash[i]; k ; k = k->next) {
/*
* Skip unwanted entries which are either not real entries or
* very difficult to interpret (wildcards...) This test needs
* lots of improvement. Any takers?
*/
key = k->key;
if (!key)
continue;
/* Skip '/defaults' */
if (STREQ(key, "/defaults"))
continue;
/* Skip '*' */
if (!fully_browsable && strchr(key, '*'))
continue;
/*
* If the map has a prefix-string then check if the key starts with
* this string, and if it does, skip over this prefix. If it has a
* prefix and it doesn't match the start of the key, skip it.
*/
if (preflen) {
if (preflen > strlen(key))
continue;
if (!NSTREQ(key, mp->am_pref, preflen))
continue;
key += preflen;
}
/* no more '/' are allowed, unless browsable_dirs=full was used */
if (!fully_browsable && strchr(key, '/'))
continue;
/* no duplicates allowed */
if (key_already_in_chain(key, current_chain))
continue;
/* fill in a cell and link the entry */
if (num_entries >= max_entries) {
/* out of space */
plog(XLOG_DEBUG, "make_entry_chain: no more space in chain");
if (num_entries > 0) {
chain[num_entries - 1].ne_nextentry = 0;
retval = &chain[0];
}
return retval;
}
/* we have space. put entry in next cell */
++last_cookie;
chain[num_entries].ne_fileid = (u_int) last_cookie;
*(u_int *) chain[num_entries].ne_cookie = (u_int) last_cookie;
chain[num_entries].ne_name = key;
if (num_entries < max_entries - 1) { /* link to next one */
chain[num_entries].ne_nextentry = &chain[num_entries + 1];
}
++num_entries;
} /* end of "while (k)" */
} /* end of "for (i ... NKVHASH ..." */
/* terminate chain */
if (num_entries > 0) {
chain[num_entries - 1].ne_nextentry = 0;
retval = &chain[0];
}
return retval;
}
/* This one is called only if map is browsable */
static int
amfs_readdir_browsable(am_node *mp, nfscookie cookie, nfsdirlist *dp, nfsentry *ep, u_int count, int fully_browsable)
{
u_int gen = *(u_int *) cookie;
int chain_length, i;
static nfsentry *te, *te_next;
static int j;
dp->dl_eof = FALSE; /* assume readdir not done */
if (amuDebug(D_READDIR))
plog(XLOG_DEBUG, "amfs_readdir_browsable gen=%u, count=%d",
gen, count);
if (gen == 0) {
/*
* In the default instance (which is used to start a search) we return
* "." and "..".
*
* This assumes that the count is big enough to allow both "." and ".."
* to be returned in a single packet. If it isn't (which would be
* fairly unbelievable) then tough.
*/
dlog("amfs_readdir_browsable: default search");
/*
* Check for enough room. This is extremely approximate but is more
* than enough space. Really need 2 times:
* 4byte fileid
* 4byte cookie
* 4byte name length
* 4byte name
* plus the dirlist structure */
if (count < (2 * (2 * (sizeof(*ep) + sizeof("..") + 4) + sizeof(*dp))))
return EINVAL;
/*
* compute # of entries to send in this chain.
* heuristics: 128 bytes per entry.
* This is too much probably, but it seems to work better because
* of the re-entrant nature of nfs_readdir, and esp. on systems
* like OpenBSD 2.2.
*/
chain_length = count / 128;
/* reset static state counters */
te = te_next = NULL;
dp->dl_entries = ep;
/* construct "." */
ep[0].ne_fileid = mp->am_gen;
ep[0].ne_name = ".";
ep[0].ne_nextentry = &ep[1];
*(u_int *) ep[0].ne_cookie = 0;
/* construct ".." */
if (mp->am_parent)
ep[1].ne_fileid = mp->am_parent->am_gen;
else
ep[1].ne_fileid = mp->am_gen;
ep[1].ne_name = "..";
ep[1].ne_nextentry = 0;
*(u_int *) ep[1].ne_cookie = DOT_DOT_COOKIE;
/*
* If map is browsable, call a function make_entry_chain() to construct
* a linked list of unmounted keys, and return it. Then link the chain
* to the regular list. Get the chain only once, but return
* chunks of it each time.
*/
te = make_entry_chain(mp, dp->dl_entries, fully_browsable);
if (!te)
return 0;
if (amuDebug(D_READDIR)) {
nfsentry *ne;
for (j = 0, ne = te; ne; ne = ne->ne_nextentry)
plog(XLOG_DEBUG, "gen1 key %4d \"%s\"", j++, ne->ne_name);
}
/* return only "chain_length" entries */
te_next = te;
for (i=1; i<chain_length; ++i) {
te_next = te_next->ne_nextentry;
if (!te_next)
break;
}
if (te_next) {
nfsentry *te_saved = te_next->ne_nextentry;
te_next->ne_nextentry = NULL; /* terminate "te" chain */
te_next = te_saved; /* save rest of "te" for next iteration */
dp->dl_eof = FALSE; /* tell readdir there's more */
} else {
dp->dl_eof = TRUE; /* tell readdir that's it */
}
ep[1].ne_nextentry = te; /* append this chunk of "te" chain */
if (amuDebug(D_READDIR)) {
nfsentry *ne;
for (j = 0, ne = te; ne; ne = ne->ne_nextentry)
plog(XLOG_DEBUG, "gen2 key %4d \"%s\"", j++, ne->ne_name);
for (j = 0, ne = ep; ne; ne = ne->ne_nextentry)
plog(XLOG_DEBUG, "gen2+ key %4d \"%s\" fi=%d ck=%d",
j++, ne->ne_name, ne->ne_fileid, *(u_int *)ne->ne_cookie);
plog(XLOG_DEBUG, "EOF is %d", dp->dl_eof);
}
return 0;
} /* end of "if (gen == 0)" statement */
dlog("amfs_readdir_browsable: real child");
if (gen == DOT_DOT_COOKIE) {
dlog("amfs_readdir_browsable: End of readdir in %s", mp->am_path);
dp->dl_eof = TRUE;
dp->dl_entries = 0;
return 0;
}
/*
* If browsable directories, then continue serving readdir() with another
* chunk of entries, starting from where we left off (when gen was equal
* to 0). Once again, assume last chunk served to readdir.
*/
dp->dl_eof = TRUE;
dp->dl_entries = ep;
te = te_next; /* reset 'te' from last saved te_next */
if (!te) { /* another indicator of end of readdir */
dp->dl_entries = 0;
return 0;
}
/*
* compute # of entries to send in this chain.
* heuristics: 128 bytes per entry.
*/
chain_length = count / 128;
/* return only "chain_length" entries */
for (i = 1; i < chain_length; ++i) {
te_next = te_next->ne_nextentry;
if (!te_next)
break;
}
if (te_next) {
nfsentry *te_saved = te_next->ne_nextentry;
te_next->ne_nextentry = NULL; /* terminate "te" chain */
te_next = te_saved; /* save rest of "te" for next iteration */
dp->dl_eof = FALSE; /* tell readdir there's more */
}
ep = te; /* send next chunk of "te" chain */
dp->dl_entries = ep;
if (amuDebug(D_READDIR)) {
nfsentry *ne;
plog(XLOG_DEBUG, "dl_entries=%p, te_next=%p, dl_eof=%d",
dp->dl_entries, te_next, dp->dl_eof);
for (ne = te; ne; ne = ne->ne_nextentry)
plog(XLOG_DEBUG, "gen3 key %4d \"%s\"", j++, ne->ne_name);
}
return 0;
}
/*
* This readdir function which call a special version of it that allows
* browsing if browsable_dirs=yes was set on the map.
*/
int
amfs_generic_readdir(am_node *mp, nfscookie cookie, nfsdirlist *dp, nfsentry *ep, u_int count)
{
u_int gen = *(u_int *) cookie;
am_node *xp;
mntent_t mnt;
dp->dl_eof = FALSE; /* assume readdir not done */
/* check if map is browsable */
if (mp->am_mnt && mp->am_mnt->mf_mopts) {
mnt.mnt_opts = mp->am_mnt->mf_mopts;
if (amu_hasmntopt(&mnt, "fullybrowsable"))
return amfs_readdir_browsable(mp, cookie, dp, ep, count, TRUE);
if (amu_hasmntopt(&mnt, "browsable"))
return amfs_readdir_browsable(mp, cookie, dp, ep, count, FALSE);
}
/* when gen is 0, we start reading from the beginning of the directory */
if (gen == 0) {
/*
* In the default instance (which is used to start a search) we return
* "." and "..".
*
* This assumes that the count is big enough to allow both "." and ".."
* to be returned in a single packet. If it isn't (which would be
* fairly unbelievable) then tough.
*/
dlog("amfs_generic_readdir: default search");
/*
* Check for enough room. This is extremely approximate but is more
* than enough space. Really need 2 times:
* 4byte fileid
* 4byte cookie
* 4byte name length
* 4byte name
* plus the dirlist structure */
if (count < (2 * (2 * (sizeof(*ep) + sizeof("..") + 4) + sizeof(*dp))))
return EINVAL;
xp = next_nonerror_node(mp->am_child);
dp->dl_entries = ep;
/* construct "." */
ep[0].ne_fileid = mp->am_gen;
ep[0].ne_name = ".";
ep[0].ne_nextentry = &ep[1];
*(u_int *) ep[0].ne_cookie = 0;
/* construct ".." */
if (mp->am_parent)
ep[1].ne_fileid = mp->am_parent->am_gen;
else
ep[1].ne_fileid = mp->am_gen;
ep[1].ne_name = "..";
ep[1].ne_nextentry = 0;
*(u_int *) ep[1].ne_cookie = (xp ? xp->am_gen : DOT_DOT_COOKIE);
if (!xp)
dp->dl_eof = TRUE; /* by default assume readdir done */
if (amuDebug(D_READDIR)) {
nfsentry *ne;
int j;
for (j = 0, ne = ep; ne; ne = ne->ne_nextentry)
plog(XLOG_DEBUG, "gen1 key %4d \"%s\" fi=%d ck=%d",
j++, ne->ne_name, ne->ne_fileid, *(u_int *)ne->ne_cookie);
}
return 0;
}
dlog("amfs_generic_readdir: real child");
if (gen == DOT_DOT_COOKIE) {
dlog("amfs_generic_readdir: End of readdir in %s", mp->am_path);
dp->dl_eof = TRUE;
dp->dl_entries = 0;
if (amuDebug(D_READDIR))
plog(XLOG_DEBUG, "end of readdir eof=TRUE, dl_entries=0\n");
return 0;
}
/* non-browsable directories code */
xp = mp->am_child;
while (xp && xp->am_gen != gen)
xp = xp->am_osib;
if (xp) {
int nbytes = count / 2; /* conservative */
int todo = MAX_READDIR_ENTRIES;
dp->dl_entries = ep;
do {
am_node *xp_next = next_nonerror_node(xp->am_osib);
if (xp_next) {
*(u_int *) ep->ne_cookie = xp_next->am_gen;
} else {
*(u_int *) ep->ne_cookie = DOT_DOT_COOKIE;
dp->dl_eof = TRUE;
}
ep->ne_fileid = xp->am_gen;
ep->ne_name = xp->am_name;
nbytes -= sizeof(*ep) + 1;
if (xp->am_name)
nbytes -= strlen(xp->am_name);
xp = xp_next;
if (nbytes > 0 && !dp->dl_eof && todo > 1) {
ep->ne_nextentry = ep + 1;
ep++;
--todo;
} else {
todo = 0;
}
} while (todo > 0);
ep->ne_nextentry = 0;
if (amuDebug(D_READDIR)) {
nfsentry *ne;
int j;
for (j=0,ne=ep; ne; ne=ne->ne_nextentry)
plog(XLOG_DEBUG, "gen2 key %4d \"%s\" fi=%d ck=%d",
j++, ne->ne_name, ne->ne_fileid, *(u_int *)ne->ne_cookie);
}
return 0;
}
return ESTALE;
}
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