Update.

	* nscd/connections.c: Implement r/o sharing of nscd's cache with client
	processes via shared memory.
	* nscd/nscd-client.h: Likewise.
	* nscd/nscd.h: Likewise.
	* nscd/nscd_conf.c: Likewise.
	* nscd/nscd_getgr_r.c: Likewise.
	* nscd/nscd_getpw_r.c: Likewise.
	* nscd/nscd_gethst_r.c: Likewise.
	* nscd/nscd.conf: Add new config parameters.
	* nscd/Makefile (aux): Add nscd_helper.
	* nscd/nscd_helper.c: New file.
	* nscd/mem.c (gc): Indicate beginning and end of the gc cycle.

	* nscd/hstcache.c: Simplify a lot.  We cache only the request itself,
	no derived information.
	* connections.c (nscd_init): Fix bug in testing size of the persistent.

	* nis/Makefile (aux): Add nis_hash.
	* nis/nis_hash.c: New file.  Split out from nis_util.c.
	* nis/nis_util.c: Move __nis_hash code in separate file.

	* csu/tst-atomic.c: Improve atomic_increment_val test which would
	not have found a ppc bug.

1 files changed, 335 insertions, 0 deletions

diff --git a/nscd/nscd_helper.c b/nscd/nscd_helper.c
new file mode 100644
index 0000000000..95661b6ff3
--- /dev/null
+++ b/nscd/nscd_helper.c
@@ -0,0 +1,335 @@
+/* Copyright (C) 1998-2002, 2003, 2004 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.
+
+   The GNU C Library 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.
+
+   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.  */
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/poll.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+#include <not-cancel.h>
+#include <nis/rpcsvc/nis.h>
+
+#include "nscd-client.h"
+
+
+static int
+open_socket (void)
+{
+  int sock = __socket (PF_UNIX, SOCK_STREAM, 0);
+  if (sock < 0)
+    return -1;
+
+  /* Make socket non-blocking.  */
+  int fl = __fcntl (sock, F_GETFL);
+  if (fl != -1)
+    __fcntl (sock, F_SETFL, fl | O_NONBLOCK);
+
+  struct sockaddr_un sun;
+  sun.sun_family = AF_UNIX;
+  strcpy (sun.sun_path, _PATH_NSCDSOCKET);
+  if (__connect (sock, (struct sockaddr *) &sun, sizeof (sun)) < 0
+      && errno != EINPROGRESS)
+    goto out;
+
+  struct pollfd fds[1];
+  fds[0].fd = sock;
+  fds[0].events = POLLOUT | POLLERR | POLLHUP;
+  if (__poll (fds, 1, 5 * 1000) > 0)
+    /* Success.  We do not check for success of the connect call here.
+       If it failed, the following operations will fail.  */
+    return sock;
+
+ out:
+  close_not_cancel_no_status (sock);
+
+  return -1;
+}
+
+
+void
+__nscd_unmap (struct mapped_database *mapped)
+{
+  assert (mapped->counter == 0);
+  munmap ((void *) mapped->head, mapped->mapsize);
+  free (mapped);
+}
+
+
+/* Try to get a file descriptor for the shared meory segment
+   containing the database.  */
+static struct mapped_database *
+get_mapping (request_type type, const char *key,
+	     struct mapped_database **mappedp)
+{
+  struct mapped_database *result = NO_MAPPING;
+#ifdef SCM_RIGHTS
+  const size_t keylen = strlen (key) + 1;
+  char resdata[keylen];
+  int saved_errno = errno;
+
+  int mapfd = -1;
+
+  /* Send the request.  */
+  struct iovec iov[2];
+  request_header req;
+
+  int sock = open_socket ();
+  if (sock < 0)
+    goto out;
+
+  req.version = NSCD_VERSION;
+  req.type = type;
+  req.key_len = keylen;
+
+  iov[0].iov_base = &req;
+  iov[0].iov_len = sizeof (req);
+  iov[1].iov_base = (void *) key;
+  iov[1].iov_len = keylen;
+
+  if (TEMP_FAILURE_RETRY (__writev (sock, iov, 2))
+      != iov[0].iov_len + iov[1].iov_len)
+    /* We cannot even write the request.  */
+    goto out_close2;
+
+  /* Room for the data sent along with the file descriptor.  We expect
+     the key name back.  */
+  iov[0].iov_base = resdata;
+  iov[0].iov_len = keylen;
+
+  char buf[CMSG_SPACE (sizeof (int))];
+  struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1,
+			.msg_control = buf, .msg_controllen = sizeof (buf) };
+  struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);
+
+  cmsg->cmsg_level = SOL_SOCKET;
+  cmsg->cmsg_type = SCM_RIGHTS;
+  cmsg->cmsg_len = CMSG_LEN (sizeof (int));
+
+  *(int *) CMSG_DATA (cmsg) = -1;
+
+  msg.msg_controllen = cmsg->cmsg_len;
+
+  struct pollfd fds[1];
+  fds[0].fd = sock;
+  fds[0].events = POLLIN | POLLERR | POLLHUP;
+  if (__poll (fds, 1, 5 * 1000) <= 0)
+    /* Failure or timeout.  */
+    goto out_close2;
+
+  if (TEMP_FAILURE_RETRY (__recvmsg (sock, &msg, 0)) != keylen
+      || msg.msg_controllen != CMSG_LEN (sizeof (int)))
+    goto out_close2;
+
+  mapfd = *(int *) CMSG_DATA (cmsg);
+
+  struct stat64 st;
+  if (strcmp (resdata, key) != 0
+      || fstat64 (mapfd, &st) != 0
+      || st.st_size < sizeof (struct database_pers_head))
+    goto out_close;
+
+  struct database_pers_head head;
+  if (TEMP_FAILURE_RETRY (__pread (mapfd, &head, sizeof (head), 0))
+      != sizeof (head))
+    goto out_close;
+
+  if (head.version != DB_VERSION || head.header_size != sizeof (head)
+      /* This really should not happen but who knows, maybe the update
+	 thread got stuck.  */
+      || head.timestamp + MAPPING_TIMEOUT < time (NULL))
+    goto out_close;
+
+  size_t size = (sizeof (head) + roundup (head.module * sizeof (ref_t), ALIGN)
+		 + head.data_size);
+
+  if (st.st_size < size)
+    goto out_close;
+
+  /* The file is large enough, map it now.  */
+  void *mapping = __mmap (NULL, size, PROT_READ, MAP_SHARED, mapfd, 0);
+  if (mapping != MAP_FAILED)
+    {
+      /* Allocate a record for the mapping.  */
+      struct mapped_database *newp;
+
+      newp = malloc (sizeof (*newp));
+      if (newp == NULL)
+	{
+	  /* Ugh, after all we went through the memory allocation failed.  */
+	  munmap (result, size);
+	  goto out_close;
+	}
+
+      newp->head = mapping;
+      newp->data = ((char *) mapping + head.header_size
+		    + roundup (head.module * sizeof (ref_t), ALIGN));
+      newp->mapsize = size;
+      /* Set counter to 1 to show it is usable.  */
+      newp->counter = 1;
+
+      result = newp;
+    }
+
+ out_close:
+  __close (mapfd);
+ out_close2:
+  __close (sock);
+ out:
+  __set_errno (saved_errno);
+#endif	/* SCM_RIGHTS */
+
+  struct mapped_database *oldval = *mappedp;
+  *mappedp = result;
+
+  if (oldval != NULL && atomic_decrement_val (&oldval->counter) == 0)
+    __nscd_unmap (oldval);
+
+  return result;
+}
+
+
+struct mapped_database *
+__nscd_get_map_ref (request_type type, const char *name,
+		    struct locked_map_ptr *mapptr, int *gc_cyclep)
+{
+  struct mapped_database *cur = mapptr->mapped;
+  if (cur == NO_MAPPING)
+    return cur;
+
+  int cnt = 0;
+  while (atomic_compare_and_exchange_val_acq (&mapptr->lock, 1, 0) != 0)
+    {
+      // XXX Best number of rounds?
+      if (++cnt > 5)
+	return NO_MAPPING;
+
+      atomic_delay ();
+    }
+
+  cur = mapptr->mapped;
+
+  if (__builtin_expect (cur != NO_MAPPING, 1))
+    {
+      /* If not mapped or timestamp not updated, request new map.  */
+      if (cur == NULL
+	  // XXX The following syscalls increases the cost of the entire
+	  // XXX lookup by a factor of 5 but unfortunately there is not
+	  // XXX much we can do except hoping we get a userlevel
+	  // XXX implementation soon.
+	  || cur->head->timestamp + MAPPING_TIMEOUT < time (NULL))
+	cur = get_mapping (type, name, &mapptr->mapped);
+
+      if (__builtin_expect (cur != NO_MAPPING, 1))
+	{
+	  if (__builtin_expect (((*gc_cyclep = cur->head->gc_cycle) & 1) != 0,
+				0))
+	    cur = NO_MAPPING;
+	  else
+	    atomic_increment (&cur->counter);
+	}
+    }
+
+  mapptr->lock = 0;
+
+  return cur;
+}
+
+
+const struct datahead *
+__nscd_cache_search (request_type type, const char *key, size_t keylen,
+		     const struct mapped_database *mapped)
+{
+  unsigned long int hash = __nis_hash (key, keylen) % mapped->head->module;
+
+  ref_t work = mapped->head->array[hash];
+  while (work != ENDREF)
+    {
+      struct hashentry *here = (struct hashentry *) (mapped->data + work);
+
+      if (type == here->type && keylen == here->len
+	  && memcmp (key, mapped->data + here->key, keylen) == 0)
+	{
+	  /* We found the entry.  Increment the appropriate counter.  */
+	  const struct datahead *dh
+	    = (struct datahead *) (mapped->data + here->packet);
+
+	  /* See whether we must ignore the entry or whether something
+	     is wrong because garbage collection is in progress.  */
+	  if (dh->usable && ((char *) dh + dh->allocsize
+			     <= (char *) mapped->head + mapped->mapsize))
+	    return dh;
+	}
+
+      work = here->next;
+    }
+
+  return NULL;
+}
+
+
+/* Create a socket connected to a name. */
+int
+__nscd_open_socket (const char *key, size_t keylen, request_type type,
+		    void *response, size_t responselen)
+{
+  int saved_errno = errno;
+
+  int sock = open_socket ();
+  if (sock >= 0)
+    {
+      request_header req;
+      req.version = NSCD_VERSION;
+      req.type = type;
+      req.key_len = keylen;
+
+      struct iovec vec[2];
+      vec[0].iov_base = &req;
+      vec[0].iov_len = sizeof (request_header);
+      vec[1].iov_base = (void *) key;
+      vec[1].iov_len = keylen;
+
+      ssize_t nbytes = TEMP_FAILURE_RETRY (__writev (sock, vec, 2));
+      if (nbytes == (ssize_t) (sizeof (request_header) + keylen))
+	{
+	  /* Wait for data.  */
+	  struct pollfd fds[1];
+	  fds[0].fd = sock;
+	  fds[0].events = POLLIN | POLLERR | POLLHUP;
+	  if (__poll (fds, 1, 5 * 1000) > 0)
+	    {
+	      nbytes = TEMP_FAILURE_RETRY (__read (sock, response,
+						   responselen));
+	      if (nbytes == (ssize_t) responselen)
+		return sock;
+	    }
+	}
+
+      close_not_cancel_no_status (sock);
+    }
+
+  __set_errno (saved_errno);
+
+  return -1;
+}