mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 04:50:07 +00:00
74158740ea
* ncsd/aicache.c: Don't use sendfile for records on the stack. * nscd/grpcache.c: Likewise. * nscd/hstcache.c: Likewise. * nscd/initgrcache.c: Likewise. * nscd/pwdcache.c: Likewise. Patch by dmueller@suse.com.
509 lines
14 KiB
C
509 lines
14 KiB
C
/* Cache handling for host lookup.
|
|
Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License version 2 as
|
|
published by the Free Software Foundation.
|
|
|
|
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, write to the Free Software Foundation,
|
|
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
|
|
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <libintl.h>
|
|
#include <netdb.h>
|
|
#include <string.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
#include <sys/mman.h>
|
|
|
|
#include "dbg_log.h"
|
|
#include "nscd.h"
|
|
#ifdef HAVE_SENDFILE
|
|
# include <kernel-features.h>
|
|
#endif
|
|
|
|
|
|
typedef enum nss_status (*nss_gethostbyname3_r)
|
|
(const char *name, int af, struct hostent *host,
|
|
char *buffer, size_t buflen, int *errnop,
|
|
int *h_errnop, int32_t *, char **);
|
|
typedef enum nss_status (*nss_getcanonname_r)
|
|
(const char *name, char *buffer, size_t buflen, char **result,
|
|
int *errnop, int *h_errnop);
|
|
|
|
|
|
static const ai_response_header notfound =
|
|
{
|
|
.version = NSCD_VERSION,
|
|
.found = 0,
|
|
.naddrs = 0,
|
|
.addrslen = 0,
|
|
.canonlen = 0,
|
|
.error = 0
|
|
};
|
|
|
|
|
|
static void
|
|
addhstaiX (struct database_dyn *db, int fd, request_header *req,
|
|
void *key, uid_t uid, struct hashentry *he, struct datahead *dh)
|
|
{
|
|
/* Search for the entry matching the key. Please note that we don't
|
|
look again in the table whether the dataset is now available. We
|
|
simply insert it. It does not matter if it is in there twice. The
|
|
pruning function only will look at the timestamp. */
|
|
|
|
/* We allocate all data in one memory block: the iov vector,
|
|
the response header and the dataset itself. */
|
|
struct dataset
|
|
{
|
|
struct datahead head;
|
|
ai_response_header resp;
|
|
char strdata[0];
|
|
} *dataset = NULL;
|
|
|
|
if (__builtin_expect (debug_level > 0, 0))
|
|
{
|
|
if (he == NULL)
|
|
dbg_log (_("Haven't found \"%s\" in hosts cache!"), (char *) key);
|
|
else
|
|
dbg_log (_("Reloading \"%s\" in hosts cache!"), (char *) key);
|
|
}
|
|
|
|
#if 0
|
|
uid_t oldeuid = 0;
|
|
if (db->secure)
|
|
{
|
|
oldeuid = geteuid ();
|
|
pthread_seteuid_np (uid);
|
|
}
|
|
#endif
|
|
|
|
static service_user *hosts_database;
|
|
service_user *nip = NULL;
|
|
int no_more;
|
|
int rc6 = 0;
|
|
int rc4 = 0;
|
|
int herrno = 0;
|
|
|
|
if (hosts_database != NULL)
|
|
{
|
|
nip = hosts_database;
|
|
no_more = 0;
|
|
}
|
|
else
|
|
no_more = __nss_database_lookup ("hosts", NULL,
|
|
"dns [!UNAVAIL=return] files", &nip);
|
|
|
|
if (__res_maybe_init (&_res, 0) == -1)
|
|
no_more = 1;
|
|
|
|
/* If we are looking for both IPv4 and IPv6 address we don't want
|
|
the lookup functions to automatically promote IPv4 addresses to
|
|
IPv6 addresses. Currently this is decided by setting the
|
|
RES_USE_INET6 bit in _res.options. */
|
|
int old_res_options = _res.options;
|
|
_res.options &= ~RES_USE_INET6;
|
|
|
|
size_t tmpbuf6len = 512;
|
|
char *tmpbuf6 = alloca (tmpbuf6len);
|
|
size_t tmpbuf4len = 0;
|
|
char *tmpbuf4 = NULL;
|
|
char *canon = NULL;
|
|
int32_t ttl = UINT32_MAX;
|
|
ssize_t total = 0;
|
|
char *key_copy = NULL;
|
|
bool alloca_used = false;
|
|
|
|
while (!no_more)
|
|
{
|
|
int status[2] = { NSS_STATUS_UNAVAIL, NSS_STATUS_UNAVAIL };
|
|
|
|
/* Prefer the function which also returns the TTL and canonical name. */
|
|
nss_gethostbyname3_r fct = __nss_lookup_function (nip,
|
|
"gethostbyname3_r");
|
|
if (fct == NULL)
|
|
fct = __nss_lookup_function (nip, "gethostbyname2_r");
|
|
|
|
if (fct != NULL)
|
|
{
|
|
struct hostent th[2];
|
|
|
|
/* Collect IPv6 information first. */
|
|
while (1)
|
|
{
|
|
rc6 = 0;
|
|
status[0] = DL_CALL_FCT (fct, (key, AF_INET6, &th[0], tmpbuf6,
|
|
tmpbuf6len, &rc6, &herrno,
|
|
&ttl, &canon));
|
|
if (rc6 != ERANGE || herrno != NETDB_INTERNAL)
|
|
break;
|
|
tmpbuf6 = extend_alloca (tmpbuf6, tmpbuf6len, 2 * tmpbuf6len);
|
|
}
|
|
|
|
if (rc6 != 0 && herrno == NETDB_INTERNAL)
|
|
goto out;
|
|
|
|
/* If the IPv6 lookup has been successful do not use the
|
|
buffer used in that lookup, use a new one. */
|
|
if (status[0] == NSS_STATUS_SUCCESS && rc6 == 0)
|
|
{
|
|
tmpbuf4len = 512;
|
|
tmpbuf4 = alloca (tmpbuf4len);
|
|
}
|
|
else
|
|
{
|
|
tmpbuf4len = tmpbuf6len;
|
|
tmpbuf4 = tmpbuf6;
|
|
}
|
|
|
|
/* Next collect IPv4 information first. */
|
|
while (1)
|
|
{
|
|
rc4 = 0;
|
|
status[1] = DL_CALL_FCT (fct, (key, AF_INET, &th[1], tmpbuf4,
|
|
tmpbuf4len, &rc4, &herrno,
|
|
ttl == UINT32_MAX ? &ttl : NULL,
|
|
canon == NULL ? &canon : NULL));
|
|
if (rc4 != ERANGE || herrno != NETDB_INTERNAL)
|
|
break;
|
|
tmpbuf4 = extend_alloca (tmpbuf4, tmpbuf4len, 2 * tmpbuf4len);
|
|
}
|
|
|
|
if (rc4 != 0 || herrno == NETDB_INTERNAL)
|
|
goto out;
|
|
|
|
if (status[0] == NSS_STATUS_SUCCESS
|
|
|| status[1] == NSS_STATUS_SUCCESS)
|
|
{
|
|
/* We found the data. Count the addresses and the size. */
|
|
int naddrs = 0;
|
|
size_t addrslen = 0;
|
|
for (int j = 0; j < 2; ++j)
|
|
if (status[j] == NSS_STATUS_SUCCESS)
|
|
for (int i = 0; th[j].h_addr_list[i] != NULL; ++i)
|
|
{
|
|
++naddrs;
|
|
addrslen += th[j].h_length;
|
|
}
|
|
|
|
if (canon == NULL)
|
|
{
|
|
/* Determine the canonical name. */
|
|
nss_getcanonname_r cfct;
|
|
cfct = __nss_lookup_function (nip, "getcanonname_r");
|
|
if (cfct != NULL)
|
|
{
|
|
const size_t max_fqdn_len = 256;
|
|
char *buf = alloca (max_fqdn_len);
|
|
char *s;
|
|
int rc;
|
|
|
|
if (DL_CALL_FCT (cfct, (key, buf, max_fqdn_len, &s, &rc,
|
|
&herrno)) == NSS_STATUS_SUCCESS)
|
|
canon = s;
|
|
else
|
|
/* Set to name now to avoid using gethostbyaddr. */
|
|
canon = key;
|
|
}
|
|
else
|
|
{
|
|
struct hostent *he = NULL;
|
|
int herrno;
|
|
struct hostent he_mem;
|
|
void *addr;
|
|
size_t addrlen;
|
|
int addrfamily;
|
|
|
|
if (status[1] == NSS_STATUS_SUCCESS)
|
|
{
|
|
addr = th[1].h_addr_list[0];
|
|
addrlen = sizeof (struct in_addr);
|
|
addrfamily = AF_INET;
|
|
}
|
|
else
|
|
{
|
|
addr = th[0].h_addr_list[0];
|
|
addrlen = sizeof (struct in6_addr);
|
|
addrfamily = AF_INET6;
|
|
}
|
|
|
|
size_t tmpbuflen = 512;
|
|
char *tmpbuf = alloca (tmpbuflen);
|
|
int rc;
|
|
while (1)
|
|
{
|
|
rc = __gethostbyaddr_r (addr, addrlen, addrfamily,
|
|
&he_mem, tmpbuf, tmpbuflen,
|
|
&he, &herrno);
|
|
if (rc != ERANGE || herrno != NETDB_INTERNAL)
|
|
break;
|
|
tmpbuf = extend_alloca (tmpbuf, tmpbuflen,
|
|
tmpbuflen * 2);
|
|
}
|
|
|
|
if (rc == 0)
|
|
{
|
|
if (he != NULL)
|
|
canon = he->h_name;
|
|
else
|
|
canon = key;
|
|
}
|
|
}
|
|
}
|
|
size_t canonlen = canon == NULL ? 0 : (strlen (canon) + 1);
|
|
|
|
total = sizeof (*dataset) + naddrs + addrslen + canonlen;
|
|
|
|
/* Now we can allocate the data structure. */
|
|
if (he == NULL)
|
|
{
|
|
dataset = (struct dataset *) mempool_alloc (db,
|
|
total
|
|
+ req->key_len);
|
|
if (dataset == NULL)
|
|
++db->head->addfailed;
|
|
}
|
|
|
|
if (dataset == NULL)
|
|
{
|
|
/* We cannot permanently add the result in the moment. But
|
|
we can provide the result as is. Store the data in some
|
|
temporary memory. */
|
|
dataset = (struct dataset *) alloca (total + req->key_len);
|
|
|
|
/* We cannot add this record to the permanent database. */
|
|
alloca_used = true;
|
|
}
|
|
|
|
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;
|
|
|
|
/* Compute the timeout time. */
|
|
dataset->head.timeout = time (NULL) + MIN (db->postimeout, ttl);
|
|
|
|
dataset->resp.version = NSCD_VERSION;
|
|
dataset->resp.found = 1;
|
|
dataset->resp.naddrs = naddrs;
|
|
dataset->resp.addrslen = addrslen;
|
|
dataset->resp.canonlen = canonlen;
|
|
dataset->resp.error = NETDB_SUCCESS;
|
|
|
|
char *addrs = (char *) (&dataset->resp + 1);
|
|
uint8_t *family = (uint8_t *) (addrs + addrslen);
|
|
|
|
for (int j = 0; j < 2; ++j)
|
|
if (status[j] == NSS_STATUS_SUCCESS)
|
|
for (int i = 0; th[j].h_addr_list[i] != NULL; ++i)
|
|
{
|
|
addrs = mempcpy (addrs, th[j].h_addr_list[i],
|
|
th[j].h_length);
|
|
*family++ = th[j].h_addrtype;
|
|
}
|
|
|
|
void *cp = family;
|
|
if (canon != NULL)
|
|
cp = mempcpy (cp, canon, canonlen);
|
|
|
|
key_copy = memcpy (cp, key, 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 (total + req->key_len == dh->allocsize
|
|
&& total - offsetof (struct dataset, resp) == 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->nreloads;
|
|
}
|
|
else
|
|
{
|
|
/* We have to create a new record. Just allocate
|
|
appropriate memory and copy it. */
|
|
struct dataset *newp
|
|
= (struct dataset *) mempool_alloc (db,
|
|
total
|
|
+ req->key_len);
|
|
if (newp != NULL)
|
|
{
|
|
/* Adjust pointer into the memory block. */
|
|
key_copy = (char *) newp + (key_copy
|
|
- (char *) dataset);
|
|
|
|
dataset = memcpy (newp, dataset,
|
|
total + req->key_len);
|
|
alloca_used = false;
|
|
}
|
|
|
|
/* Mark the old record as obsolete. */
|
|
dh->usable = false;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* 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) && !alloca_used)
|
|
{
|
|
assert (db->wr_fd != -1);
|
|
assert ((char *) &dataset->resp > (char *) db->data);
|
|
assert ((char *) &dataset->resp - (char *) db->head
|
|
+ total
|
|
<= (sizeof (struct database_pers_head)
|
|
+ db->head->module * sizeof (ref_t)
|
|
+ db->head->data_size));
|
|
ssize_t written;
|
|
written = sendfileall (fd, db->wr_fd,
|
|
(char *) &dataset->resp
|
|
- (char *) db->head, total);
|
|
# ifndef __ASSUME_SENDFILE
|
|
if (written == -1 && errno == ENOSYS)
|
|
goto use_write;
|
|
# endif
|
|
}
|
|
else
|
|
# ifndef __ASSUME_SENDFILE
|
|
use_write:
|
|
# endif
|
|
#endif
|
|
writeall (fd, &dataset->resp, total);
|
|
}
|
|
|
|
goto out;
|
|
}
|
|
|
|
}
|
|
|
|
if (nss_next_action (nip, status[1]) == NSS_ACTION_RETURN)
|
|
break;
|
|
|
|
if (nip->next == NULL)
|
|
no_more = -1;
|
|
else
|
|
nip = nip->next;
|
|
}
|
|
|
|
/* No result found. Create a negative result record. */
|
|
if (he != NULL && rc4 == EAGAIN)
|
|
{
|
|
/* If we have an old record available but cannot find one now
|
|
because the service is not available we keep the old record
|
|
and make sure it does not get removed. */
|
|
if (reload_count != UINT_MAX && dh->nreloads == reload_count)
|
|
/* Do not reset the value if we never not reload the record. */
|
|
dh->nreloads = reload_count - 1;
|
|
}
|
|
else
|
|
{
|
|
/* We have no data. This means we send the standard reply for
|
|
this case. */
|
|
total = sizeof (notfound);
|
|
|
|
if (fd != -1)
|
|
TEMP_FAILURE_RETRY (send (fd, ¬found, total, MSG_NOSIGNAL));
|
|
|
|
dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len);
|
|
/* 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. */
|
|
dataset->head.timeout = time (NULL) + db->negtimeout;
|
|
|
|
/* This is the reply. */
|
|
memcpy (&dataset->resp, ¬found, total);
|
|
|
|
/* Copy the key data. */
|
|
key_copy = memcpy (dataset->strdata, key, req->key_len);
|
|
}
|
|
else
|
|
++db->head->addfailed;
|
|
}
|
|
|
|
out:
|
|
_res.options = old_res_options;
|
|
|
|
#if 0
|
|
if (db->secure)
|
|
pthread_seteuid_np (oldeuid);
|
|
#endif
|
|
|
|
if (dataset != NULL && !alloca_used)
|
|
{
|
|
/* 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);
|
|
}
|
|
|
|
/* Now get the lock to safely insert the records. */
|
|
pthread_rwlock_rdlock (&db->lock);
|
|
|
|
if (cache_add (req->type, key_copy, req->key_len, &dataset->head, true,
|
|
db, uid) < 0)
|
|
/* Ensure the data can be recovered. */
|
|
dataset->head.usable = false;
|
|
|
|
pthread_rwlock_unlock (&db->lock);
|
|
|
|
/* Mark the old entry as obsolete. */
|
|
if (dh != NULL)
|
|
dh->usable = false;
|
|
}
|
|
}
|
|
|
|
|
|
void
|
|
addhstai (struct database_dyn *db, int fd, request_header *req, void *key,
|
|
uid_t uid)
|
|
{
|
|
addhstaiX (db, fd, req, key, uid, NULL, NULL);
|
|
}
|
|
|
|
|
|
void
|
|
readdhstai (struct database_dyn *db, struct hashentry *he, struct datahead *dh)
|
|
{
|
|
request_header req =
|
|
{
|
|
.type = GETAI,
|
|
.key_len = he->len
|
|
};
|
|
|
|
addhstaiX (db, -1, &req, db->data + he->key, he->owner, he, dh);
|
|
}
|