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-rw-r--r--nscd/servicescache.c473
1 files changed, 473 insertions, 0 deletions
diff --git a/nscd/servicescache.c b/nscd/servicescache.c
new file mode 100644
index 0000000000..ea4fa35100
--- /dev/null
+++ b/nscd/servicescache.c
@@ -0,0 +1,473 @@
+/* Cache handling for services lookup.
+ Copyright (C) 2007 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@drepper.com>, 2007.
+
+ 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 <alloca.h>
+#include <assert.h>
+#include <errno.h>
+#include <libintl.h>
+#include <netdb.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include "nscd.h"
+#include "dbg_log.h"
+
+
+/* This is the standard reply in case the service is disabled. */
+static const serv_response_header disabled =
+{
+ .version = NSCD_VERSION,
+ .found = -1,
+ .s_name_len = 0,
+ .s_proto_len = 0,
+ .s_aliases_cnt = 0,
+ .s_port = -1
+};
+
+/* This is the struct describing how to write this record. */
+const struct iovec serv_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 serv_response_header notfound =
+{
+ .version = NSCD_VERSION,
+ .found = 0,
+ .s_name_len = 0,
+ .s_proto_len = 0,
+ .s_aliases_cnt = 0,
+ .s_port = -1
+};
+
+
+static void
+cache_addserv (struct database_dyn *db, int fd, request_header *req,
+ const void *key, struct servent *serv, uid_t owner,
+ struct hashentry *he, struct datahead *dh, int errval)
+{
+ ssize_t total;
+ ssize_t written;
+ time_t t = time (NULL);
+
+ /* We allocate all data in one memory block: the iov vector,
+ the response header and the dataset itself. */
+ struct dataset
+ {
+ struct datahead head;
+ serv_response_header resp;
+ char strdata[0];
+ } *dataset;
+
+ assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
+
+ if (serv == NULL)
+ {
+ if (he != NULL && errval == 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)
+ /* Do not reset the value if we never not reload the record. */
+ dh->nreloads = reload_count - 1;
+
+ written = total = 0;
+ }
+ else
+ {
+ /* We have no data. This means we send the standard reply for this
+ case. */
+ total = sizeof (notfound);
+
+ written = TEMP_FAILURE_RETRY (send (fd, &notfound, 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 = t + db->negtimeout;
+
+ /* This is the reply. */
+ memcpy (&dataset->resp, &notfound, total);
+
+ /* Copy the key data. */
+ memcpy (dataset->strdata, key, req->key_len);
+
+ /* 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 (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;
+
+ pthread_rwlock_unlock (&db->lock);
+
+ /* Mark the old entry as obsolete. */
+ if (dh != NULL)
+ dh->usable = false;
+ }
+ else
+ ++db->head->addfailed;
+ }
+ }
+ else
+ {
+ /* Determine the I/O structure. */
+ size_t s_name_len = strlen (serv->s_name) + 1;
+ size_t s_proto_len = strlen (serv->s_proto) + 1;
+ uint32_t *s_aliases_len;
+ size_t s_aliases_cnt;
+ char *aliases;
+ char *cp;
+ size_t cnt;
+
+ /* Determine the number of aliases. */
+ s_aliases_cnt = 0;
+ for (cnt = 0; serv->s_aliases[cnt] != NULL; ++cnt)
+ ++s_aliases_cnt;
+ /* Determine the length of all aliases. */
+ s_aliases_len = (uint32_t *) alloca (s_aliases_cnt * sizeof (uint32_t));
+ total = 0;
+ for (cnt = 0; cnt < s_aliases_cnt; ++cnt)
+ {
+ s_aliases_len[cnt] = strlen (serv->s_aliases[cnt]) + 1;
+ total += s_aliases_len[cnt];
+ }
+
+ total += (sizeof (struct dataset)
+ + s_name_len
+ + s_proto_len
+ + s_aliases_cnt * sizeof (uint32_t));
+ written = total;
+
+ /* If we refill the cache, first assume the reconrd did not
+ change. Allocate memory on the cache since it is likely
+ discarded anyway. If it turns out to be necessary to have a
+ new record we can still allocate real memory. */
+ bool alloca_used = false;
+ dataset = NULL;
+
+ 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 = t + db->postimeout;
+
+ dataset->resp.version = NSCD_VERSION;
+ dataset->resp.found = 1;
+ dataset->resp.s_name_len = s_name_len;
+ dataset->resp.s_proto_len = s_proto_len;
+ dataset->resp.s_port = serv->s_port;
+ dataset->resp.s_aliases_cnt = s_aliases_cnt;
+
+ cp = dataset->strdata;
+
+ cp = mempcpy (cp, serv->s_name, s_name_len);
+ cp = mempcpy (cp, serv->s_proto, s_proto_len);
+ cp = mempcpy (cp, s_aliases_len, s_aliases_cnt * sizeof (uint32_t));
+
+ /* Then the aliases. */
+ aliases = cp;
+ for (cnt = 0; cnt < s_aliases_cnt; ++cnt)
+ cp = mempcpy (cp, serv->s_aliases[cnt], s_aliases_len[cnt]);
+
+ assert (cp
+ == dataset->strdata + total - offsetof (struct dataset,
+ strdata));
+
+ char *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 pointers into the memory block. */
+ 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;
+ }
+
+ /* 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 keep the receiver waiting. */
+ 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));
+ 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
+ written = writeall (fd, &dataset->resp, total);
+ }
+
+ /* Add the record to the database. But only if it has not been
+ stored on the stack. */
+ if (! 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, owner) < 0)
+ /* Could not allocate memory. Make sure the
+ data gets discarded. */
+ dataset->head.usable = false;
+
+ pthread_rwlock_unlock (&db->lock);
+ }
+ }
+
+ if (__builtin_expect (written != total, 0) && debug_level > 0)
+ {
+ char buf[256];
+ dbg_log (_("short write in %s: %s"), __FUNCTION__,
+ strerror_r (errno, buf, sizeof (buf)));
+ }
+}
+
+
+static int
+lookup (int type, char *key, struct servent *resultbufp, char *buffer,
+ size_t buflen, struct servent **serv)
+{
+ char *proto = strrchr (key, '/');
+ if (proto != NULL && proto != key)
+ {
+ key = strndupa (key, proto - key);
+ if (proto[1] == '\0')
+ proto = NULL;
+ else
+ ++proto;
+ }
+
+ if (type == GETSERVBYNAME)
+ return __getservbyname_r (key, proto, resultbufp, buffer, buflen, serv);
+
+ assert (type == GETSERVBYPORT);
+ return __getservbyport_r (atol (key), proto, resultbufp, buffer, buflen,
+ serv);
+}
+
+
+static void
+addservbyX (struct database_dyn *db, int fd, request_header *req,
+ char *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. */
+ size_t buflen = 1024;
+ char *buffer = (char *) alloca (buflen);
+ struct servent resultbuf;
+ struct servent *serv;
+ bool use_malloc = false;
+ int errval = 0;
+
+ if (__builtin_expect (debug_level > 0, 0))
+ {
+ if (he == NULL)
+ dbg_log (_("Haven't found \"%s\" in services cache!"), key);
+ else
+ dbg_log (_("Reloading \"%s\" in services cache!"), key);
+ }
+
+ while (lookup (req->type, key, &resultbuf, buffer, buflen, &serv) != 0
+ && (errval = errno) == ERANGE)
+ {
+ errno = 0;
+
+ if (__builtin_expect (buflen > 32768, 0))
+ {
+ char *old_buffer = buffer;
+ buflen *= 2;
+ buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
+ if (buffer == NULL)
+ {
+ /* We ran out of memory. We cannot do anything but
+ sending a negative response. In reality this should
+ never happen. */
+ serv = NULL;
+ buffer = old_buffer;
+
+ /* 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. */
+ errval = EAGAIN;
+ break;
+ }
+ use_malloc = true;
+ }
+ else
+ /* Allocate a new buffer on the stack. If possible combine it
+ with the previously allocated buffer. */
+ buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
+ }
+
+ cache_addserv (db, fd, req, key, serv, uid, he, dh, errval);
+
+ if (use_malloc)
+ free (buffer);
+}
+
+
+void
+addservbyname (struct database_dyn *db, int fd, request_header *req,
+ void *key, uid_t uid)
+{
+ addservbyX (db, fd, req, key, uid, NULL, NULL);
+}
+
+
+void
+readdservbyname (struct database_dyn *db, struct hashentry *he,
+ struct datahead *dh)
+{
+ request_header req =
+ {
+ .type = GETSERVBYNAME,
+ .key_len = he->len
+ };
+
+ addservbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
+}
+
+
+void
+addservbyport (struct database_dyn *db, int fd, request_header *req,
+ void *key, uid_t uid)
+{
+ addservbyX (db, fd, req, key, uid, NULL, NULL);
+}
+
+
+void
+readdservbyport (struct database_dyn *db, struct hashentry *he,
+ struct datahead *dh)
+{
+ request_header req =
+ {
+ .type = GETSERVBYPORT,
+ .key_len = he->len
+ };
+
+ addservbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
+}
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