445 lines
11 KiB
C
445 lines
11 KiB
C
/* Inner loops of cache daemon.
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Copyright (C) 1998, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <assert.h>
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#include <error.h>
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#include <errno.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <arpa/inet.h>
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#include <sys/param.h>
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#include <sys/poll.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/un.h>
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#include "nscd.h"
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#include "dbg_log.h"
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/* Mapping of request type to database. */
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static const dbtype serv2db[LASTDBREQ + 1] =
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{
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[GETPWBYNAME] = pwddb,
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[GETPWBYUID] = pwddb,
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[GETGRBYNAME] = grpdb,
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[GETGRBYGID] = grpdb,
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[GETHOSTBYNAME] = hstdb,
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[GETHOSTBYNAMEv6] = hstdb,
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[GETHOSTBYADDR] = hstdb,
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[GETHOSTBYADDRv6] = hstdb,
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};
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/* Map request type to a string. */
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const char *serv2str[LASTREQ] =
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{
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[GETPWBYNAME] = "GETPWBYNAME",
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[GETPWBYUID] = "GETPWBYUID",
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[GETGRBYNAME] = "GETGRBYNAME",
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[GETGRBYGID] = "GETGRBYGID",
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[GETHOSTBYNAME] = "GETHOSTBYNAME",
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[GETHOSTBYNAMEv6] = "GETHOSTBYNAMEv6",
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[GETHOSTBYADDR] = "GETHOSTBYADDR",
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[GETHOSTBYADDRv6] = "GETHOSTBYADDRv6",
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[SHUTDOWN] = "SHUTDOWN",
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[GETSTAT] = "GETSTAT"
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};
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/* The control data structures for the services. */
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static struct database dbs[lastdb] =
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{
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[pwddb] = {
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lock: PTHREAD_RWLOCK_INITIALIZER,
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enabled: 0,
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check_file: 1,
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filename: "/etc/passwd",
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module: 211,
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disabled_iov: &pwd_iov_disabled,
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postimeout: 3600,
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negtimeout: 20
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},
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[grpdb] = {
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lock: PTHREAD_RWLOCK_INITIALIZER,
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enabled: 0,
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check_file: 1,
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filename: "/etc/group",
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module: 211,
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disabled_iov: &grp_iov_disabled,
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postimeout: 3600,
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negtimeout: 60
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},
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[hstdb] = {
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lock: PTHREAD_RWLOCK_INITIALIZER,
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enabled: 0,
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check_file: 1,
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filename: "/etc/hosts",
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module: 211,
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disabled_iov: &hst_iov_disabled,
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postimeout: 3600,
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negtimeout: 20
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}
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};
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/* Number of seconds between two cache pruning runs. */
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#define CACHE_PRUNE_INTERVAL 15
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/* Number of threads to use. */
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int nthreads = -1;
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/* Socket for incoming connections. */
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static int sock;
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/* Initialize database information structures. */
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void
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nscd_init (const char *conffile)
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{
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struct sockaddr_un sock_addr;
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size_t cnt;
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/* Read the configuration file. */
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if (nscd_parse_file (conffile, dbs) != 0)
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{
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/* We couldn't read the configuration file. Disable all services
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by shutting down the srever. */
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dbg_log (_("cannot read configuration file; this is fatal"));
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exit (1);
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}
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if (nthreads == -1)
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/* No configuration for this value, assume a default. */
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nthreads = 2 * lastdb;
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for (cnt = 0; cnt < lastdb; ++cnt)
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if (dbs[cnt].enabled)
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{
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pthread_rwlock_init (&dbs[cnt].lock, NULL);
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dbs[cnt].array = (struct hashentry **)
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calloc (dbs[cnt].module, sizeof (struct hashentry *));
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if (dbs[cnt].array == NULL)
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error (EXIT_FAILURE, errno, "while allocating cache");
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if (dbs[cnt].check_file)
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{
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/* We need the modification date of the file. */
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struct stat st;
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if (stat (dbs[cnt].filename, &st) < 0)
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{
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char buf[128];
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/* We cannot stat() the file, disable file checking. */
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dbg_log (_("cannot stat() file `%s': %s"),
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dbs[cnt].filename,
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strerror_r (errno, buf, sizeof (buf)));
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dbs[cnt].check_file = 0;
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}
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else
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dbs[cnt].file_mtime = st.st_mtime;
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}
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}
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/* Create the socket. */
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sock = socket (AF_UNIX, SOCK_STREAM, 0);
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if (sock < 0)
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{
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dbg_log (_("cannot open socket: %s"), strerror (errno));
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exit (1);
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}
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/* Bind a name to the socket. */
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sock_addr.sun_family = AF_UNIX;
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strcpy (sock_addr.sun_path, _PATH_NSCDSOCKET);
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if (bind (sock, (struct sockaddr *) &sock_addr, sizeof (sock_addr)) < 0)
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{
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dbg_log ("%s: %s", _PATH_NSCDSOCKET, strerror (errno));
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exit (1);
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}
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/* Set permissions for the socket. */
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chmod (_PATH_NSCDSOCKET, 0666);
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/* Set the socket up to accept connections. */
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if (listen (sock, SOMAXCONN) < 0)
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{
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dbg_log (_("cannot enable socket to accept connections: %s"),
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strerror (errno));
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exit (1);
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}
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}
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/* Close the connections. */
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void
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close_sockets (void)
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{
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close (sock);
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}
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/* Handle new request. */
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static void
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handle_request (int fd, request_header *req, void *key)
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{
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if (debug_level > 0)
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dbg_log (_("handle_request: request received (Version = %d)"),
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req->version);
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if (req->version != NSCD_VERSION)
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{
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dbg_log (_("\
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cannot handle old request version %d; current version is %d"),
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req->version, NSCD_VERSION);
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return;
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}
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if (req->type >= GETPWBYNAME && req->type <= LASTDBREQ)
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{
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struct hashentry *cached;
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struct database *db = &dbs[serv2db[req->type]];
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if (debug_level > 0)
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{
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if (req->type == GETHOSTBYADDR || req->type == GETHOSTBYADDRv6)
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{
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char buf[INET6_ADDRSTRLEN];
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dbg_log ("\t%s (%s)", serv2str[req->type],
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inet_ntop (req->type == GETHOSTBYADDR
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? AF_INET : AF_INET6,
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key, buf, sizeof (buf)));
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}
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else
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dbg_log ("\t%s (%s)", serv2str[req->type], key);
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}
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/* Is this service enabled? */
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if (!db->enabled)
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{
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/* No, sent the prepared record. */
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if (TEMP_FAILURE_RETRY (write (fd, db->disabled_iov->iov_base,
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db->disabled_iov->iov_len))
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!= db->disabled_iov->iov_len)
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{
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/* We have problems sending the result. */
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char buf[256];
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dbg_log (_("cannot write result: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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}
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return;
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}
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/* Be sure we can read the data. */
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pthread_rwlock_rdlock (&db->lock);
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/* See whether we can handle it from the cache. */
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cached = (struct hashentry *) cache_search (req->type, key, req->key_len,
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db);
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if (cached != NULL)
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{
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/* Hurray it's in the cache. */
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if (TEMP_FAILURE_RETRY (write (fd, cached->packet, cached->total))
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!= cached->total)
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{
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/* We have problems sending the result. */
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char buf[256];
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dbg_log (_("cannot write result: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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}
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pthread_rwlock_unlock (&db->lock);
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return;
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}
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pthread_rwlock_unlock (&db->lock);
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}
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else
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if (debug_level > 0)
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dbg_log ("\t%s", serv2str[req->type]);
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/* Handle the request. */
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switch (req->type)
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{
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case GETPWBYNAME:
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addpwbyname (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETPWBYUID:
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addpwbyuid (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETGRBYNAME:
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addgrbyname (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETGRBYGID:
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addgrbygid (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETHOSTBYNAME:
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addhstbyname (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETHOSTBYNAMEv6:
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addhstbynamev6 (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETHOSTBYADDR:
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addhstbyaddr (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETHOSTBYADDRv6:
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addhstbyaddrv6 (&dbs[serv2db[req->type]], fd, req, key);
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break;
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case GETSTAT:
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send_stats (fd, dbs);
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break;
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case SHUTDOWN:
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termination_handler (0);
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break;
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default:
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abort ();
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}
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}
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/* This is the main loop. It is replicated in different threads but the
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`poll' call makes sure only one thread handles an incoming connection. */
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static void *
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__attribute__ ((__noreturn__))
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nscd_run (void *p)
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{
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int my_number = (int) p;
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struct pollfd conn;
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int run_prune = my_number < lastdb && dbs[my_number].enabled;
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time_t now = time (NULL);
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time_t next_prune = now + CACHE_PRUNE_INTERVAL;
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int timeout = run_prune ? 1000 * (next_prune - now) : -1;
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conn.fd = sock;
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conn.events = POLLRDNORM;
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while (1)
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{
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int nr = poll (&conn, 1, timeout);
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if (nr == 0)
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{
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/* The `poll' call timed out. It's time to clean up the cache. */
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assert (my_number < lastdb);
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now = time (NULL);
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prune_cache (&dbs[my_number], now);
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next_prune = now + CACHE_PRUNE_INTERVAL;
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timeout = 1000 * (next_prune - now);
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continue;
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}
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/* We have a new incoming connection. */
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if (conn.revents & (POLLRDNORM|POLLERR|POLLHUP|POLLNVAL))
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{
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/* Accept the connection. */
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int fd = accept (conn.fd, NULL, NULL);
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request_header req;
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char buf[256];
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if (fd < 0)
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{
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dbg_log (_("while accepting connection: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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continue;
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}
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/* Now read the request. */
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if (TEMP_FAILURE_RETRY (read (fd, &req, sizeof (req)))
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!= sizeof (req))
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{
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dbg_log (_("short read while reading request: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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close (fd);
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continue;
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}
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/* It should not be possible to crash the nscd with a silly
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request (i.e., a terribly large key. We limit the size
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to 1kb. */
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if (req.key_len < 0 || req.key_len > 1024)
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{
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dbg_log (_("key length in request too long: %Zd"), req.key_len);
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close (fd);
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continue;
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}
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else
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{
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/* Get the key. */
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char keybuf[req.key_len];
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if (TEMP_FAILURE_RETRY (read (fd, keybuf, req.key_len))
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!= req.key_len)
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{
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dbg_log (_("short read while reading request key: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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close (fd);
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continue;
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}
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/* Phew, we got all the data, now process it. */
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handle_request (fd, &req, keybuf);
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/* We are done. */
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close (fd);
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}
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}
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if (run_prune)
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{
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now = time (NULL);
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timeout = now < next_prune ? 1000 * (next_prune - now) : 0;
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}
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}
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}
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/* Start all the threads we want. The initial process is thread no. 1. */
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void
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start_threads (void)
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{
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int i;
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pthread_attr_t attr;
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pthread_t th;
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pthread_attr_init (&attr);
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pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
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/* We allow less than LASTDB threads only for debugging. */
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if (debug_level == 0)
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nthreads = MAX (nthreads, lastdb);
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for (i = 1; i < nthreads; ++i)
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pthread_create (&th, &attr, nscd_run, (void *) i);
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pthread_attr_destroy (&attr);
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nscd_run ((void *) 0);
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}
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