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glibc/nscd/connections.c

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/* Inner loops of cache daemon.
Copyright (C) 1998, 1999, 2000 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 Library General Public License as
published by the Free Software Foundation; either 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,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <assert.h>
#include <error.h>
#include <errno.h>
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <libintl.h>
#include <arpa/inet.h>
#include <sys/param.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include "nscd.h"
#include "dbg_log.h"
/* Mapping of request type to database. */
static const dbtype serv2db[LASTDBREQ + 1] =
{
[GETPWBYNAME] = pwddb,
[GETPWBYUID] = pwddb,
[GETGRBYNAME] = grpdb,
[GETGRBYGID] = grpdb,
[GETHOSTBYNAME] = hstdb,
[GETHOSTBYNAMEv6] = hstdb,
[GETHOSTBYADDR] = hstdb,
[GETHOSTBYADDRv6] = hstdb,
};
/* Map request type to a string. */
const char *serv2str[LASTREQ] =
{
[GETPWBYNAME] = "GETPWBYNAME",
[GETPWBYUID] = "GETPWBYUID",
[GETGRBYNAME] = "GETGRBYNAME",
[GETGRBYGID] = "GETGRBYGID",
[GETHOSTBYNAME] = "GETHOSTBYNAME",
[GETHOSTBYNAMEv6] = "GETHOSTBYNAMEv6",
[GETHOSTBYADDR] = "GETHOSTBYADDR",
[GETHOSTBYADDRv6] = "GETHOSTBYADDRv6",
[SHUTDOWN] = "SHUTDOWN",
[GETSTAT] = "GETSTAT",
[INVALIDATE] = "INVALIDATE"
};
/* The control data structures for the services. */
static struct database dbs[lastdb] =
{
[pwddb] = {
lock: PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
enabled: 0,
check_file: 1,
filename: "/etc/passwd",
module: 211,
disabled_iov: &pwd_iov_disabled,
postimeout: 3600,
negtimeout: 20
},
[grpdb] = {
lock: PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
enabled: 0,
check_file: 1,
filename: "/etc/group",
module: 211,
disabled_iov: &grp_iov_disabled,
postimeout: 3600,
negtimeout: 60
},
[hstdb] = {
lock: PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
enabled: 0,
check_file: 1,
filename: "/etc/hosts",
module: 211,
disabled_iov: &hst_iov_disabled,
postimeout: 3600,
negtimeout: 20
}
};
/* Number of seconds between two cache pruning runs. */
#define CACHE_PRUNE_INTERVAL 15
/* Number of threads to use. */
int nthreads = -1;
/* Socket for incoming connections. */
static int sock;
/* Initialize database information structures. */
void
nscd_init (const char *conffile)
{
struct sockaddr_un sock_addr;
size_t cnt;
/* Read the configuration file. */
if (nscd_parse_file (conffile, dbs) != 0)
{
/* We couldn't read the configuration file. Disable all services
by shutting down the srever. */
dbg_log (_("cannot read configuration file; this is fatal"));
exit (1);
}
if (nthreads == -1)
/* No configuration for this value, assume a default. */
nthreads = 2 * lastdb;
for (cnt = 0; cnt < lastdb; ++cnt)
if (dbs[cnt].enabled)
{
pthread_rwlock_init (&dbs[cnt].lock, NULL);
dbs[cnt].array = (struct hashentry **)
calloc (dbs[cnt].module, sizeof (struct hashentry *));
if (dbs[cnt].array == NULL)
error (EXIT_FAILURE, errno, "while allocating cache");
if (dbs[cnt].check_file)
{
/* We need the modification date of the file. */
struct stat st;
if (stat (dbs[cnt].filename, &st) < 0)
{
char buf[128];
/* We cannot stat() the file, disable file checking. */
dbg_log (_("cannot stat() file `%s': %s"),
dbs[cnt].filename,
strerror_r (errno, buf, sizeof (buf)));
dbs[cnt].check_file = 0;
}
else
dbs[cnt].file_mtime = st.st_mtime;
}
}
/* Create the socket. */
sock = socket (AF_UNIX, SOCK_STREAM, 0);
if (sock < 0)
{
dbg_log (_("cannot open socket: %s"), strerror (errno));
exit (1);
}
/* Bind a name to the socket. */
sock_addr.sun_family = AF_UNIX;
strcpy (sock_addr.sun_path, _PATH_NSCDSOCKET);
if (bind (sock, (struct sockaddr *) &sock_addr, sizeof (sock_addr)) < 0)
{
dbg_log ("%s: %s", _PATH_NSCDSOCKET, strerror (errno));
exit (1);
}
/* Set permissions for the socket. */
chmod (_PATH_NSCDSOCKET, 0666);
/* Set the socket up to accept connections. */
if (listen (sock, SOMAXCONN) < 0)
{
dbg_log (_("cannot enable socket to accept connections: %s"),
strerror (errno));
exit (1);
}
}
/* Close the connections. */
void
close_sockets (void)
{
close (sock);
}
static void
invalidate_cache (char *key)
{
dbtype number;
if (strcmp (key, "passwd") == 0)
number = pwddb;
else if (strcmp (key, "group") == 0)
number = grpdb;
else if (strcmp (key, "hosts") == 0)
number = hstdb;
else return;
prune_cache (&dbs[number], LONG_MAX);
}
/* Handle new request. */
static void
handle_request (int fd, request_header *req, void *key, uid_t uid)
{
if (debug_level > 0)
dbg_log (_("handle_request: request received (Version = %d)"),
req->version);
if (req->version != NSCD_VERSION)
{
dbg_log (_("\
cannot handle old request version %d; current version is %d"),
req->version, NSCD_VERSION);
return;
}
if (req->type >= GETPWBYNAME && req->type <= LASTDBREQ)
{
struct hashentry *cached;
struct database *db = &dbs[serv2db[req->type]];
if (debug_level > 0)
{
if (req->type == GETHOSTBYADDR || req->type == GETHOSTBYADDRv6)
{
char buf[INET6_ADDRSTRLEN];
dbg_log ("\t%s (%s)", serv2str[req->type],
inet_ntop (req->type == GETHOSTBYADDR
? AF_INET : AF_INET6,
key, buf, sizeof (buf)));
}
else
dbg_log ("\t%s (%s)", serv2str[req->type], key);
}
/* Is this service enabled? */
if (!db->enabled)
{
/* No, sent the prepared record. */
if (TEMP_FAILURE_RETRY (write (fd, db->disabled_iov->iov_base,
db->disabled_iov->iov_len))
!= db->disabled_iov->iov_len)
{
/* We have problems sending the result. */
char buf[256];
dbg_log (_("cannot write result: %s"),
strerror_r (errno, buf, sizeof (buf)));
}
return;
}
/* Be sure we can read the data. */
pthread_rwlock_rdlock (&db->lock);
/* See whether we can handle it from the cache. */
cached = (struct hashentry *) cache_search (req->type, key, req->key_len,
db, uid);
if (cached != NULL)
{
/* Hurray it's in the cache. */
if (TEMP_FAILURE_RETRY (write (fd, cached->packet, cached->total))
!= cached->total)
{
/* We have problems sending the result. */
char buf[256];
dbg_log (_("cannot write result: %s"),
strerror_r (errno, buf, sizeof (buf)));
}
pthread_rwlock_unlock (&db->lock);
return;
}
pthread_rwlock_unlock (&db->lock);
}
else if (debug_level > 0)
{
if (req->type == INVALIDATE)
dbg_log ("\t%s (%s)", serv2str[req->type], key);
else
dbg_log ("\t%s", serv2str[req->type]);
}
/* Handle the request. */
switch (req->type)
{
case GETPWBYNAME:
addpwbyname (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETPWBYUID:
addpwbyuid (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETGRBYNAME:
addgrbyname (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETGRBYGID:
addgrbygid (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETHOSTBYNAME:
addhstbyname (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETHOSTBYNAMEv6:
addhstbynamev6 (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETHOSTBYADDR:
addhstbyaddr (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETHOSTBYADDRv6:
addhstbyaddrv6 (&dbs[serv2db[req->type]], fd, req, key, uid);
break;
case GETSTAT:
case SHUTDOWN:
case INVALIDATE:
/* Accept shutdown, getstat and invalidate only from root */
if (secure_in_use && uid == 0)
{
if (req->type == GETSTAT)
send_stats (fd, dbs);
else if (req->type == INVALIDATE)
invalidate_cache (key);
else
termination_handler (0);
}
else
{
struct ucred caller;
socklen_t optlen = sizeof (caller);
/* Some systems have no SO_PEERCRED implementation. They don't
care about security so we don't as well. */
#ifdef SO_PEERCRED
if (getsockopt (fd, SOL_SOCKET, SO_PEERCRED, &caller, &optlen) < 0)
{
char buf[256];
dbg_log (_("error getting callers id: %s"),
strerror_r (errno, buf, sizeof (buf)));
}
else
if (caller.uid == 0)
#endif
{
if (req->type == GETSTAT)
send_stats (fd, dbs);
else if (req->type == INVALIDATE)
invalidate_cache (key);
else
termination_handler (0);
}
}
break;
default:
/* Ignore the command, it's nothing we know. */
break;
}
}
/* This is the main loop. It is replicated in different threads but the
`poll' call makes sure only one thread handles an incoming connection. */
static void *
__attribute__ ((__noreturn__))
nscd_run (void *p)
{
long int my_number = (long int) p;
struct pollfd conn;
int run_prune = my_number < lastdb && dbs[my_number].enabled;
time_t now = time (NULL);
time_t next_prune = now + CACHE_PRUNE_INTERVAL;
int timeout = run_prune ? 1000 * (next_prune - now) : -1;
conn.fd = sock;
conn.events = POLLRDNORM;
while (1)
{
int nr = poll (&conn, 1, timeout);
if (nr == 0)
{
/* The `poll' call timed out. It's time to clean up the cache. */
assert (my_number < lastdb);
now = time (NULL);
prune_cache (&dbs[my_number], now);
next_prune = now + CACHE_PRUNE_INTERVAL;
timeout = 1000 * (next_prune - now);
continue;
}
/* We have a new incoming connection. */
if (conn.revents & (POLLRDNORM|POLLERR|POLLHUP|POLLNVAL))
{
/* Accept the connection. */
int fd = accept (conn.fd, NULL, NULL);
request_header req;
char buf[256];
uid_t uid = 0;
if (fd < 0)
{
dbg_log (_("while accepting connection: %s"),
strerror_r (errno, buf, sizeof (buf)));
continue;
}
/* Now read the request. */
if (TEMP_FAILURE_RETRY (read (fd, &req, sizeof (req)))
!= sizeof (req))
{
dbg_log (_("short read while reading request: %s"),
strerror_r (errno, buf, sizeof (buf)));
close (fd);
continue;
}
/* Some systems have no SO_PEERCRED implementation. They don't
care about security so we don't as well. */
#ifdef SO_PEERCRED
if (secure_in_use)
{
struct ucred caller;
socklen_t optlen = sizeof (caller);
if (getsockopt (fd, SOL_SOCKET, SO_PEERCRED,
&caller, &optlen) < 0)
{
dbg_log (_("error getting callers id: %s"),
strerror_r (errno, buf, sizeof (buf)));
close (fd);
continue;
}
if (req.type < GETPWBYNAME || req.type > LASTDBREQ
|| secure[serv2db[req.type]])
uid = caller.uid;
}
#endif
/* It should not be possible to crash the nscd with a silly
request (i.e., a terribly large key). We limit the size
to 1kb. */
if (req.key_len < 0 || req.key_len > 1024)
{
dbg_log (_("key length in request too long: %zd"), req.key_len);
close (fd);
continue;
}
else
{
/* Get the key. */
char keybuf[req.key_len];
if (TEMP_FAILURE_RETRY (read (fd, keybuf, req.key_len))
!= req.key_len)
{
dbg_log (_("short read while reading request key: %s"),
strerror_r (errno, buf, sizeof (buf)));
close (fd);
continue;
}
/* Phew, we got all the data, now process it. */
handle_request (fd, &req, keybuf, uid);
/* We are done. */
close (fd);
}
}
if (run_prune)
{
now = time (NULL);
timeout = now < next_prune ? 1000 * (next_prune - now) : 0;
}
}
}
/* Start all the threads we want. The initial process is thread no. 1. */
void
start_threads (void)
{
long int i;
pthread_attr_t attr;
pthread_t th;
pthread_attr_init (&attr);
pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
/* We allow less than LASTDB threads only for debugging. */
if (debug_level == 0)
nthreads = MAX (nthreads, lastdb);
for (i = 1; i < nthreads; ++i)
pthread_create (&th, &attr, nscd_run, (void *) i);
pthread_attr_destroy (&attr);
nscd_run ((void *) 0);
}
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