/* Cache handling for host lookup.
- Copyright (C) 1998-2002, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 1998-2008, 2009, 2011 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
+ 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.
- The GNU C Library is distributed in the hope that it will be useful,
+ 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
- Lesser General Public License for more details.
+ 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 Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ 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 <alloca.h>
#include <assert.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 void
+/* This is the standard reply in case there are temporary problems. */
+static const hst_response_header tryagain =
+{
+ .version = NSCD_VERSION,
+ .found = 0,
+ .h_name_len = 0,
+ .h_aliases_cnt = 0,
+ .h_addrtype = -1,
+ .h_length = -1,
+ .h_addr_list_cnt = 0,
+ .error = TRY_AGAIN
+};
+
+
+static time_t
cache_addhst (struct database_dyn *db, int fd, request_header *req,
const void *key, struct hostent *hst, uid_t owner,
- struct hashentry *he, struct datahead *dh, int errval)
+ struct hashentry *const he, struct datahead *dh, int errval,
+ int32_t ttl)
{
- ssize_t total;
- ssize_t written;
+ bool all_written = true;
time_t t = time (NULL);
/* We allocate all data in one memory block: the iov vector,
assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
+ time_t timeout = MAX_TIMEOUT_VALUE;
if (hst == NULL)
{
if (he != NULL && errval == EAGAIN)
/* Do not reset the value if we never not reload the record. */
dh->nreloads = reload_count - 1;
- written = total = 0;
+ /* Reload with the same time-to-live value. */
+ timeout = dh->timeout = t + dh->ttl;
}
else
{
/* We have no data. This means we send the standard reply for this
- case. */
- written = total = sizeof (notfound);
+ case. Possibly this is only temporary. */
+ ssize_t total = sizeof (notfound);
+ assert (sizeof (notfound) == sizeof (tryagain));
+
+ const hst_response_header *resp = (errval == EAGAIN
+ ? &tryagain : ¬found);
- if (fd != -1)
- written = TEMP_FAILURE_RETRY (write (fd, ¬found, total));
+ if (fd != -1 &&
+ TEMP_FAILURE_RETRY (send (fd, resp, total,
+ MSG_NOSIGNAL)) != total)
+ all_written = false;
- dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len);
/* If we cannot permanently store the result, so be it. */
- if (dataset != NULL)
+ if (__builtin_expect (db->negtimeout == 0, 0))
+ {
+ /* Mark the old entry as obsolete. */
+ if (dh != NULL)
+ dh->usable = false;
+ }
+ else if ((dataset = mempool_alloc (db, (sizeof (struct dataset)
+ + req->key_len), 1)) != NULL)
{
dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
dataset->head.recsize = total;
dataset->head.usable = true;
/* Compute the timeout time. */
- dataset->head.timeout = t + db->negtimeout;
+ dataset->head.ttl = ttl == INT32_MAX ? db->negtimeout : ttl;
+ timeout = dataset->head.timeout = t + dataset->head.ttl;
/* This is the reply. */
- memcpy (&dataset->resp, ¬found, total);
+ memcpy (&dataset->resp, resp, total);
/* Copy the key data. */
memcpy (dataset->strdata, key, req->key_len);
+ sizeof (struct dataset) + req->key_len, MS_ASYNC);
}
- /* Now get the lock to safely insert the records. */
- pthread_rwlock_rdlock (&db->lock);
-
- if (cache_add (req->type, &dataset->strdata, req->key_len,
- &dataset->head, true, db, owner) < 0)
- /* Ensure the data can be recovered. */
- dataset->head.usable = false;
+ (void) cache_add (req->type, &dataset->strdata, req->key_len,
+ &dataset->head, true, db, owner, he == NULL);
pthread_rwlock_unlock (&db->lock);
if (dh != NULL)
dh->usable = false;
}
- else
- ++db->head->addfailed;
}
}
else
size_t h_aliases_cnt;
uint32_t *h_aliases_len;
size_t h_addr_list_cnt;
- int addr_list_type;
char *addresses;
char *aliases;
char *key_copy = NULL;
char *cp;
size_t cnt;
+ ssize_t total;
/* Determine the number of aliases. */
h_aliases_cnt = 0;
/* Determine the number of addresses. */
h_addr_list_cnt = 0;
- for (cnt = 0; hst->h_addr_list[cnt]; ++cnt)
+ while (hst->h_addr_list[h_addr_list_cnt] != NULL)
++h_addr_list_cnt;
if (h_addr_list_cnt == 0)
/* Invalid entry. */
- return;
+ return MAX_TIMEOUT_VALUE;
total += (sizeof (struct dataset)
+ h_name_len
+ h_aliases_cnt * sizeof (uint32_t)
+ h_addr_list_cnt * hst->h_length);
- written = total;
/* If we refill the cache, first assume the reconrd did not
change. Allocate memory on the cache since it is likely
the current cache handling cannot handle and it is more than
questionable whether it is worthwhile complicating the cache
handling just for handling such a special case. */
- if (he == NULL && hst->h_addr_list[1] == NULL)
- {
- dataset = (struct dataset *) mempool_alloc (db,
- total + req->key_len);
- if (dataset == NULL)
- ++db->head->addfailed;
- }
+ if (he == NULL && h_addr_list_cnt == 1)
+ dataset = (struct dataset *) mempool_alloc (db, total + req->key_len,
+ 1);
if (dataset == NULL)
{
dataset->head.usable = true;
/* Compute the timeout time. */
- dataset->head.timeout = t + db->postimeout;
+ dataset->head.ttl = ttl == INT32_MAX ? db->postimeout : ttl;
+ timeout = dataset->head.timeout = t + dataset->head.ttl;
dataset->resp.version = NSCD_VERSION;
dataset->resp.found = 1;
dataset->resp.h_addr_list_cnt = h_addr_list_cnt;
dataset->resp.error = NETDB_SUCCESS;
+ /* Make sure there is no gap. */
+ assert ((char *) (&dataset->resp.error + 1) == dataset->strdata);
+
cp = dataset->strdata;
cp = mempcpy (cp, hst->h_name, h_name_len);
we explicitly add the name here. */
key_copy = memcpy (cp, key, req->key_len);
+ assert ((char *) &dataset->resp + dataset->head.recsize == cp);
+
/* Now we can determine whether on refill we have to create a new
record or not. */
if (he != NULL)
/* 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. */
+ assert (h_addr_list_cnt == 1);
+ dh->ttl = dataset->head.ttl;
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)
+ if (h_addr_list_cnt == 1)
{
- /* Adjust pointers into the memory block. */
- addresses = (char *) newp + (addresses - (char *) dataset);
- aliases = (char *) newp + (aliases - (char *) dataset);
- if (key_copy != NULL)
- key_copy = (char *) newp + (key_copy - (char *) dataset);
-
- dataset = memcpy (newp, dataset, total + req->key_len);
- alloca_used = false;
+ /* 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,
+ 1);
+ if (newp != NULL)
+ {
+ /* Adjust pointers into the memory block. */
+ addresses = (char *) newp + (addresses
+ - (char *) dataset);
+ aliases = (char *) newp + (aliases - (char *) dataset);
+ assert (key_copy != NULL);
+ 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. */
unnecessarily keep the receiver waiting. */
assert (fd != -1);
- written = TEMP_FAILURE_RETRY (write (fd, &dataset->resp, total));
+#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 - (char *) db->head
+ + total
+ <= (sizeof (struct database_pers_head)
+ + db->head->module * sizeof (ref_t)
+ + db->head->data_size));
+ ssize_t written = sendfileall (fd, db->wr_fd,
+ (char *) &dataset->resp
+ - (char *) db->head,
+ dataset->head.recsize);
+ if (written != dataset->head.recsize)
+ {
+# ifndef __ASSUME_SENDFILE
+ if (written == -1 && errno == ENOSYS)
+ goto use_write;
+# endif
+ all_written = false;
+ }
+ }
+ else
+# ifndef __ASSUME_SENDFILE
+ use_write:
+# endif
+#endif
+ if (writeall (fd, &dataset->resp, dataset->head.recsize)
+ != dataset->head.recsize)
+ all_written = false;
}
/* Add the record to the database. But only if it has not been
+ total + req->key_len, MS_ASYNC);
}
- addr_list_type = (hst->h_length == NS_INADDRSZ
- ? GETHOSTBYADDR : GETHOSTBYADDRv6);
-
- /* Now get the lock to safely insert the records. */
- pthread_rwlock_rdlock (&db->lock);
-
/* NB: the following code is really complicated. It has
seemlingly duplicated code paths which do the same. The
problem is that we always must add the hash table entry
|| req->type == GETHOSTBYADDR
|| req->type == GETHOSTBYADDRv6);
- if (cache_add (req->type, key_copy, req->key_len,
- &dataset->head, true, db, owner) < 0)
- /* Could not allocate memory. Make sure the
- data gets discarded. */
- dataset->head.usable = false;
+ (void) cache_add (req->type, key_copy, req->key_len,
+ &dataset->head, true, db, owner, he == NULL);
pthread_rwlock_unlock (&db->lock);
}
}
- if (__builtin_expect (written != total, 0) && debug_level > 0)
+ if (__builtin_expect (!all_written, 0) && debug_level > 0)
{
char buf[256];
dbg_log (_("short write in %s: %s"), __FUNCTION__,
strerror_r (errno, buf, sizeof (buf)));
}
+
+ return timeout;
}
static int
lookup (int type, void *key, struct hostent *resultbufp, char *buffer,
- size_t buflen, struct hostent **hst)
+ size_t buflen, struct hostent **hst, int32_t *ttlp)
{
if (type == GETHOSTBYNAME)
- return __gethostbyname2_r (key, AF_INET, resultbufp, buffer, buflen, hst,
- &h_errno);
+ return __gethostbyname3_r (key, AF_INET, resultbufp, buffer, buflen, hst,
+ &h_errno, ttlp, NULL);
if (type == GETHOSTBYNAMEv6)
- return __gethostbyname2_r (key, AF_INET6, resultbufp, buffer, buflen, hst,
- &h_errno);
+ return __gethostbyname3_r (key, AF_INET6, resultbufp, buffer, buflen, hst,
+ &h_errno, ttlp, NULL);
if (type == GETHOSTBYADDR)
- return __gethostbyaddr_r (key, NS_INADDRSZ, AF_INET, resultbufp, buffer,
- buflen, hst, &h_errno);
- return __gethostbyaddr_r (key, NS_IN6ADDRSZ, AF_INET6, resultbufp, buffer,
- buflen, hst, &h_errno);
+ return __gethostbyaddr2_r (key, NS_INADDRSZ, AF_INET, resultbufp, buffer,
+ buflen, hst, &h_errno, ttlp);
+ return __gethostbyaddr2_r (key, NS_IN6ADDRSZ, AF_INET6, resultbufp, buffer,
+ buflen, hst, &h_errno, ttlp);
}
-static void
+static time_t
addhstbyX (struct database_dyn *db, int fd, request_header *req,
void *key, uid_t uid, struct hashentry *he, struct datahead *dh)
{
char *buffer = (char *) alloca (buflen);
struct hostent resultbuf;
struct hostent *hst;
- uid_t oldeuid = 0;
bool use_malloc = false;
int errval = 0;
+ int32_t ttl = INT32_MAX;
if (__builtin_expect (debug_level > 0, 0))
{
dbg_log (_("Reloading \"%s\" in hosts cache!"), (char *) str);
}
- if (db->secure)
- {
- oldeuid = geteuid ();
- seteuid (uid);
- }
-
- while (lookup (req->type, key, &resultbuf, buffer, buflen, &hst) != 0
+ while (lookup (req->type, key, &resultbuf, buffer, buflen, &hst, &ttl) != 0
&& h_errno == NETDB_INTERNAL
&& (errval = errno) == ERANGE)
{
- char *old_buffer = buffer;
errno = 0;
-#define INCR 1024
if (__builtin_expect (buflen > 32768, 0))
{
- buflen += INCR;
+ char *old_buffer = buffer;
+ buflen *= 2;
buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
if (buffer == NULL)
{
/* We set the error to indicate this is (possibly) a
temporary error and that it does not mean the entry
is not available at all. */
+ h_errno = TRY_AGAIN;
errval = EAGAIN;
break;
}
else
/* Allocate a new buffer on the stack. If possible combine it
with the previously allocated buffer. */
- buffer = (char *) extend_alloca (buffer, buflen, buflen + INCR);
+ buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
}
- if (db->secure)
- seteuid (oldeuid);
-
- cache_addhst (db, fd, req, key, hst, uid, he, dh,
- h_errno == TRY_AGAIN ? errval : 0);
+ time_t timeout = cache_addhst (db, fd, req, key, hst, uid, he, dh,
+ h_errno == TRY_AGAIN ? errval : 0, ttl);
if (use_malloc)
free (buffer);
+
+ return timeout;
}
}
-void
+time_t
readdhstbyname (struct database_dyn *db, struct hashentry *he,
struct datahead *dh)
{
.key_len = he->len
};
- addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
+ return addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
}
}
-void
+time_t
readdhstbyaddr (struct database_dyn *db, struct hashentry *he,
struct datahead *dh)
{
.key_len = he->len
};
- addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
+ return addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
}
}
-void
+time_t
readdhstbynamev6 (struct database_dyn *db, struct hashentry *he,
struct datahead *dh)
{
.key_len = he->len
};
- addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
+ return addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
}
}
-void
+time_t
readdhstbyaddrv6 (struct database_dyn *db, struct hashentry *he,
struct datahead *dh)
{
.key_len = he->len
};
- addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
+ return addhstbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
}
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