glibc/nscd/netgroupcache.c
2012-02-09 23:18:22 +00:00

669 lines
17 KiB
C

/* Cache handling for netgroup lookup.
Copyright (C) 2011 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>. */
#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <libintl.h>
#include <stdbool.h>
#include <unistd.h>
#include <sys/mman.h>
#include "../inet/netgroup.h"
#include "nscd.h"
#include "dbg_log.h"
#ifdef HAVE_SENDFILE
# include <kernel-features.h>
#endif
/* This is the standard reply in case the service is disabled. */
static const netgroup_response_header disabled =
{
.version = NSCD_VERSION,
.found = -1,
.nresults = 0,
.result_len = 0
};
/* This is the struct describing how to write this record. */
const struct iovec netgroup_iov_disabled =
{
.iov_base = (void *) &disabled,
.iov_len = sizeof (disabled)
};
/* This is the standard reply in case we haven't found the dataset. */
static const netgroup_response_header notfound =
{
.version = NSCD_VERSION,
.found = 0,
.nresults = 0,
.result_len = 0
};
struct dataset
{
struct datahead head;
netgroup_response_header resp;
char strdata[0];
};
static time_t
addgetnetgrentX (struct database_dyn *db, int fd, request_header *req,
const char *key, uid_t uid, struct hashentry *he,
struct datahead *dh, struct dataset **resultp)
{
if (__builtin_expect (debug_level > 0, 0))
{
if (he == NULL)
dbg_log (_("Haven't found \"%s\" in netgroup cache!"), key);
else
dbg_log (_("Reloading \"%s\" in netgroup cache!"), key);
}
static service_user *netgroup_database;
time_t timeout;
struct dataset *dataset;
bool cacheable = false;
ssize_t total;
char *key_copy = NULL;
struct __netgrent data;
size_t buflen = MAX (1024, sizeof (*dataset) + req->key_len);
size_t buffilled = sizeof (*dataset);
char *buffer = NULL;
size_t nentries = 0;
bool use_malloc = false;
size_t group_len = strlen (key) + 1;
union
{
struct name_list elem;
char mem[sizeof (struct name_list) + group_len];
} first_needed;
if (netgroup_database == NULL
&& __nss_database_lookup ("netgroup", NULL, NULL, &netgroup_database))
{
/* No such service. */
total = sizeof (notfound);
timeout = time (NULL) + db->negtimeout;
if (fd != -1)
TEMP_FAILURE_RETRY (send (fd, &notfound, total, MSG_NOSIGNAL));
dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len, 1);
/* If we cannot permanently store the result, so be it. */
if (dataset != NULL)
{
dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
dataset->head.recsize = total;
dataset->head.notfound = true;
dataset->head.nreloads = 0;
dataset->head.usable = true;
/* Compute the timeout time. */
timeout = dataset->head.timeout = time (NULL) + db->negtimeout;
dataset->head.ttl = db->negtimeout;
/* This is the reply. */
memcpy (&dataset->resp, &notfound, total);
/* Copy the key data. */
memcpy (dataset->strdata, key, req->key_len);
cacheable = true;
}
goto writeout;
}
memset (&data, '\0', sizeof (data));
buffer = alloca (buflen);
first_needed.elem.next = &first_needed.elem;
memcpy (first_needed.elem.name, key, group_len);
data.needed_groups = &first_needed.elem;
while (data.needed_groups != NULL)
{
/* Add the next group to the list of those which are known. */
struct name_list *this_group = data.needed_groups->next;
if (this_group == data.needed_groups)
data.needed_groups = NULL;
else
data.needed_groups->next = this_group->next;
this_group->next = data.known_groups;
data.known_groups = this_group;
union
{
enum nss_status (*f) (const char *, struct __netgrent *);
void *ptr;
} setfct;
service_user *nip = netgroup_database;
int no_more = __nss_lookup (&nip, "setnetgrent", NULL, &setfct.ptr);
while (!no_more)
{
enum nss_status status
= DL_CALL_FCT (*setfct.f, (data.known_groups->name, &data));
if (status == NSS_STATUS_SUCCESS)
{
union
{
enum nss_status (*f) (struct __netgrent *, char *, size_t,
int *);
void *ptr;
} getfct;
getfct.ptr = __nss_lookup_function (nip, "getnetgrent_r");
if (getfct.f != NULL)
while (1)
{
int e;
status = getfct.f (&data, buffer + buffilled,
buflen - buffilled, &e);
if (status == NSS_STATUS_RETURN)
/* This was the last one for this group. Look
at next group if available. */
break;
if (status == NSS_STATUS_SUCCESS)
{
if (data.type == triple_val)
{
const char *nhost = data.val.triple.host;
const char *nuser = data.val.triple.user;
const char *ndomain = data.val.triple.domain;
if (data.val.triple.host > data.val.triple.user
|| data.val.triple.user > data.val.triple.domain)
{
const char *last = MAX (nhost,
MAX (nuser, ndomain));
size_t bufused = (last + strlen (last) + 1
- buffer);
/* We have to make temporary copies. */
size_t hostlen = strlen (nhost) + 1;
size_t userlen = strlen (nuser) + 1;
size_t domainlen = strlen (ndomain) + 1;
size_t needed = hostlen + userlen + domainlen;
if (buflen - req->key_len - bufused < needed)
{
size_t newsize = MAX (2 * buflen,
buflen + 2 * needed);
if (use_malloc || newsize > 1024 * 1024)
{
buflen = newsize;
char *newbuf = xrealloc (use_malloc
? buffer
: NULL,
buflen);
buffer = newbuf;
use_malloc = true;
}
else
extend_alloca (buffer, buflen, newsize);
}
nhost = memcpy (buffer + bufused,
nhost, hostlen);
nuser = memcpy ((char *) nhost + hostlen,
nuser, userlen);
ndomain = memcpy ((char *) nuser + userlen,
ndomain, domainlen);
}
char *wp = buffer + buffilled;
wp = stpcpy (wp, nhost) + 1;
wp = stpcpy (wp, nuser) + 1;
wp = stpcpy (wp, ndomain) + 1;
buffilled = wp - buffer;
++nentries;
}
else
{
/* Check that the group has not been
requested before. */
struct name_list *runp = data.needed_groups;
if (runp != NULL)
while (1)
{
if (strcmp (runp->name, data.val.group) == 0)
break;
runp = runp->next;
if (runp == data.needed_groups)
{
runp = NULL;
break;
}
}
if (runp == NULL)
{
runp = data.known_groups;
while (runp != NULL)
if (strcmp (runp->name, data.val.group) == 0)
break;
else
runp = runp->next;
}
if (runp == NULL)
{
/* A new group is requested. */
size_t namelen = strlen (data.val.group) + 1;
struct name_list *newg = alloca (sizeof (*newg)
+ namelen);
memcpy (newg->name, data.val.group, namelen);
if (data.needed_groups == NULL)
data.needed_groups = newg->next = newg;
else
{
newg->next = data.needed_groups->next;
data.needed_groups->next = newg;
data.needed_groups = newg;
}
}
}
}
else if (status == NSS_STATUS_UNAVAIL && e == ERANGE)
{
size_t newsize = 2 * buflen;
if (use_malloc || newsize > 1024 * 1024)
{
buflen = newsize;
char *newbuf = xrealloc (use_malloc
? buffer : NULL, buflen);
buffer = newbuf;
use_malloc = true;
}
else
extend_alloca (buffer, buflen, newsize);
}
}
enum nss_status (*endfct) (struct __netgrent *);
endfct = __nss_lookup_function (nip, "endnetgrent");
if (endfct != NULL)
(void) DL_CALL_FCT (*endfct, (&data));
break;
}
no_more = __nss_next2 (&nip, "setnetgrent", NULL, &setfct.ptr,
status, 0);
}
}
total = buffilled;
/* Fill in the dataset. */
dataset = (struct dataset *) buffer;
dataset->head.allocsize = total + req->key_len;
dataset->head.recsize = total - offsetof (struct dataset, resp);
dataset->head.notfound = false;
dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
dataset->head.usable = true;
dataset->head.ttl = db->postimeout;
timeout = dataset->head.timeout = time (NULL) + dataset->head.ttl;
dataset->resp.version = NSCD_VERSION;
dataset->resp.found = 1;
dataset->resp.nresults = nentries;
dataset->resp.result_len = buffilled - sizeof (*dataset);
assert (buflen - buffilled >= req->key_len);
key_copy = memcpy (buffer + buffilled, key, req->key_len);
buffilled += req->key_len;
/* Now we can determine whether on refill we have to create a new
record or not. */
if (he != NULL)
{
assert (fd == -1);
if (dataset->head.allocsize == dh->allocsize
&& dataset->head.recsize == dh->recsize
&& memcmp (&dataset->resp, dh->data,
dh->allocsize - offsetof (struct dataset, resp)) == 0)
{
/* The data has not changed. We will just bump the timeout
value. Note that the new record has been allocated on
the stack and need not be freed. */
dh->timeout = dataset->head.timeout;
dh->ttl = dataset->head.ttl;
++dh->nreloads;
dataset = (struct dataset *) dh;
goto out;
}
}
{
struct dataset *newp
= (struct dataset *) mempool_alloc (db, total + req->key_len, 1);
if (__builtin_expect (newp != NULL, 1))
{
/* Adjust pointer into the memory block. */
key_copy = (char *) newp + (key_copy - buffer);
dataset = memcpy (newp, dataset, total + req->key_len);
cacheable = true;
if (he != NULL)
/* Mark the old record as obsolete. */
dh->usable = false;
}
}
if (he == NULL && fd != -1)
{
/* We write the dataset before inserting it to the database
since while inserting this thread might block and so would
unnecessarily let the receiver wait. */
writeout:
#ifdef HAVE_SENDFILE
if (__builtin_expect (db->mmap_used, 1) && cacheable)
{
assert (db->wr_fd != -1);
assert ((char *) &dataset->resp > (char *) db->data);
assert ((char *) dataset - (char *) db->head + total
<= (sizeof (struct database_pers_head)
+ db->head->module * sizeof (ref_t)
+ db->head->data_size));
# ifndef __ASSUME_SENDFILE
ssize_t written =
# endif
sendfileall (fd, db->wr_fd, (char *) &dataset->resp
- (char *) db->head, dataset->head.recsize);
# ifndef __ASSUME_SENDFILE
if (written == -1 && errno == ENOSYS)
goto use_write;
# endif
}
else
#endif
{
#if defined HAVE_SENDFILE && !defined __ASSUME_SENDFILE
use_write:
#endif
writeall (fd, &dataset->resp, dataset->head.recsize);
}
}
if (cacheable)
{
/* If necessary, we also propagate the data to disk. */
if (db->persistent)
{
// XXX async OK?
uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
msync ((void *) pval,
((uintptr_t) dataset & pagesize_m1) + total + req->key_len,
MS_ASYNC);
}
(void) cache_add (req->type, key_copy, req->key_len, &dataset->head,
true, db, uid, he == NULL);
pthread_rwlock_unlock (&db->lock);
/* Mark the old entry as obsolete. */
if (dh != NULL)
dh->usable = false;
}
out:
if (use_malloc)
free (buffer);
*resultp = dataset;
return timeout;
}
static time_t
addinnetgrX (struct database_dyn *db, int fd, request_header *req,
char *key, uid_t uid, struct hashentry *he,
struct datahead *dh)
{
const char *group = key;
key = (char *) rawmemchr (key, '\0') + 1;
size_t group_len = key - group - 1;
const char *host = *key++ ? key : NULL;
if (host != NULL)
key = (char *) rawmemchr (key, '\0') + 1;
const char *user = *key++ ? key : NULL;
if (user != NULL)
key = (char *) rawmemchr (key, '\0') + 1;
const char *domain = *key++ ? key : NULL;
if (__builtin_expect (debug_level > 0, 0))
{
if (he == NULL)
dbg_log (_("Haven't found \"%s (%s,%s,%s)\" in netgroup cache!"),
group, host ?: "", user ?: "", domain ?: "");
else
dbg_log (_("Reloading \"%s (%s,%s,%s)\" in netgroup cache!"),
group, host ?: "", user ?: "", domain ?: "");
}
struct dataset *result = (struct dataset *) cache_search (GETNETGRENT,
group, group_len,
db, uid);
time_t timeout;
if (result != NULL)
timeout = result->head.timeout;
else
{
request_header req_get =
{
.type = GETNETGRENT,
.key_len = group_len
};
timeout = addgetnetgrentX (db, -1, &req_get, group, uid, NULL, NULL,
&result);
}
struct indataset
{
struct datahead head;
innetgroup_response_header resp;
} *dataset
= (struct indataset *) mempool_alloc (db,
sizeof (*dataset) + req->key_len,
1);
struct indataset dataset_mem;
bool cacheable = true;
if (__builtin_expect (dataset == NULL, 0))
{
cacheable = false;
dataset = &dataset_mem;
}
dataset->head.allocsize = sizeof (*dataset) + req->key_len;
dataset->head.recsize = sizeof (innetgroup_response_header);
dataset->head.notfound = result->head.notfound;
dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
dataset->head.usable = true;
dataset->head.ttl = result->head.ttl;
dataset->head.timeout = timeout;
dataset->resp.version = NSCD_VERSION;
dataset->resp.found = result->resp.found;
/* Until we find a matching entry the result is 0. */
dataset->resp.result = 0;
char *key_copy = memcpy ((char *) (dataset + 1), group, req->key_len);
if (dataset->resp.found)
{
const char *triplets = (const char *) (&result->resp + 1);
for (nscd_ssize_t i = result->resp.nresults; i > 0; --i)
{
bool success = true;
if (host != NULL)
success = strcmp (host, triplets) == 0;
triplets = (const char *) rawmemchr (triplets, '\0') + 1;
if (success && user != NULL)
success = strcmp (user, triplets) == 0;
triplets = (const char *) rawmemchr (triplets, '\0') + 1;
if (success && (domain == NULL || strcmp (domain, triplets) == 0))
{
dataset->resp.result = 1;
break;
}
triplets = (const char *) rawmemchr (triplets, '\0') + 1;
}
}
if (he != NULL && dh->data[0].innetgroupdata.result == dataset->resp.result)
{
/* The data has not changed. We will just bump the timeout
value. Note that the new record has been allocated on
the stack and need not be freed. */
dh->timeout = timeout;
dh->ttl = dataset->head.ttl;
++dh->nreloads;
return timeout;
}
if (he == NULL)
{
/* We write the dataset before inserting it to the database
since while inserting this thread might block and so would
unnecessarily let the receiver wait. */
assert (fd != -1);
#ifdef HAVE_SENDFILE
if (__builtin_expect (db->mmap_used, 1) && cacheable)
{
assert (db->wr_fd != -1);
assert ((char *) &dataset->resp > (char *) db->data);
assert ((char *) dataset - (char *) db->head + sizeof (*dataset)
<= (sizeof (struct database_pers_head)
+ db->head->module * sizeof (ref_t)
+ db->head->data_size));
# ifndef __ASSUME_SENDFILE
ssize_t written =
# endif
sendfileall (fd, db->wr_fd,
(char *) &dataset->resp - (char *) db->head,
sizeof (innetgroup_response_header));
# ifndef __ASSUME_SENDFILE
if (written == -1 && errno == ENOSYS)
goto use_write;
# endif
}
else
{
# ifndef __ASSUME_SENDFILE
use_write:
# endif
#endif
writeall (fd, &dataset->resp, sizeof (innetgroup_response_header));
}
}
if (cacheable)
{
/* If necessary, we also propagate the data to disk. */
if (db->persistent)
{
// XXX async OK?
uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
msync ((void *) pval,
((uintptr_t) dataset & pagesize_m1) + sizeof (*dataset)
+ req->key_len,
MS_ASYNC);
}
(void) cache_add (req->type, key_copy, req->key_len, &dataset->head,
true, db, uid, he == NULL);
pthread_rwlock_unlock (&db->lock);
/* Mark the old entry as obsolete. */
if (dh != NULL)
dh->usable = false;
}
return timeout;
}
void
addgetnetgrent (struct database_dyn *db, int fd, request_header *req,
void *key, uid_t uid)
{
struct dataset *ignore;
addgetnetgrentX (db, fd, req, key, uid, NULL, NULL, &ignore);
}
time_t
readdgetnetgrent (struct database_dyn *db, struct hashentry *he,
struct datahead *dh)
{
request_header req =
{
.type = GETNETGRENT,
.key_len = he->len
};
struct dataset *ignore;
return addgetnetgrentX (db, -1, &req, db->data + he->key, he->owner, he, dh,
&ignore);
}
void
addinnetgr (struct database_dyn *db, int fd, request_header *req,
void *key, uid_t uid)
{
addinnetgrX (db, fd, req, key, uid, NULL, NULL);
}
time_t
readdinnetgr (struct database_dyn *db, struct hashentry *he,
struct datahead *dh)
{
request_header req =
{
.type = INNETGR,
.key_len = he->len
};
return addinnetgrX (db, -1, &req, db->data + he->key, he->owner, he, dh);
}