path: root/source3/nsswitch/winbindd.c

/* 
   Unix SMB/Netbios implementation.
   Version 2.0

   Winbind daemon for ntdom nss module

   Copyright (C) Tim Potter 2000
   
   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; either version 2 of the License, or
   (at your option) any later version.
   
   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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "winbindd.h"

/* List of all connected clients */

static struct winbindd_cli_state *client_list;

/* Reload configuration */

static BOOL reload_services_file(void)
{
        pstring servicesf = CONFIGFILE;
	BOOL ret;

	reopen_logs();
	ret = lp_load(servicesf,False,False,True);

	reopen_logs();
	load_interfaces();

	return(ret);
}

/* Print client information */

static void do_print_client_info(void)
{
    struct winbindd_cli_state *client;
    int i;

    if (client_list == NULL) {
        DEBUG(0, ("no clients in list\n"));
        return;
    }

    DEBUG(0, ("client list is:\n"));

    for (client = client_list, i = 0; client; client = client->next) {
        DEBUG(0, ("client %3d: pid = %5d fd = %d read = %4d write = %4d\n", 
                  i, client->pid, client->sock, client->read_buf_len, 
                  client->write_buf_len));
        i++;
    }
}

/* Flush client cache */

static void do_flush_caches(void)
{
    /* Clear cached user and group enumation info */

    winbindd_flush_cache();
}

/* Handle the signal by unlinking socket and exiting */

static void termination_handler(int signum)
{
    pstring path;

    /* Remove socket file */

    slprintf(path, sizeof(path), "%s/%s", 
	     WINBINDD_SOCKET_DIR, WINBINDD_SOCKET_NAME);
    unlink(path);

    exit(0);
}

static BOOL print_client_info;

static void sigusr1_handler(int signum)
{
    BlockSignals(True, SIGUSR1);
    print_client_info = True;
    BlockSignals(False, SIGUSR1);
}

static BOOL flush_cache;

static void sighup_handler(int signum)
{
    BlockSignals(True, SIGHUP);
    flush_cache = True;
    BlockSignals(False, SIGHUP);
}

/* Create winbindd socket */

static int create_sock(void)
{
    struct sockaddr_un sunaddr;
    struct stat st;
    int sock;
    mode_t old_umask;
    pstring path;

    /* Create the socket directory or reuse the existing one */

    if (lstat(WINBINDD_SOCKET_DIR, &st) == -1) {

        if (errno == ENOENT) {

            /* Create directory */

            if (mkdir(WINBINDD_SOCKET_DIR, 0755) == -1) {
                DEBUG(0, ("error creating socket directory %s: %s\n",
                          WINBINDD_SOCKET_DIR, sys_errlist[errno]));
                return -1;
            }

        } else {

            DEBUG(0, ("lstat failed on socket directory %s: %s\n",
                      WINBINDD_SOCKET_DIR, sys_errlist[errno]));
            return -1;
        }

    } else {

        /* Check ownership and permission on existing directory */
        
        if (!S_ISDIR(st.st_mode)) {
            DEBUG(0, ("socket directory %s isn't a directory\n",
                      WINBINDD_SOCKET_DIR));
            return -1;
        }
        
        if ((st.st_uid != 0) || ((st.st_mode & 0777) != 0755)) {
            DEBUG(0, ("invalid permissions on socket directory %s\n",
                      WINBINDD_SOCKET_DIR));
            return -1;
        }
    }

    /* Create the socket file */

    old_umask = umask(0);

    sock = socket(AF_UNIX, SOCK_STREAM, 0);
    
    if (sock == -1) {
        perror("socket");
        return -1;
    }

    slprintf(path, sizeof(path), "%s/%s", 
	     WINBINDD_SOCKET_DIR, WINBINDD_SOCKET_NAME);

    unlink(path);
    memset(&sunaddr, 0, sizeof(sunaddr));
    sunaddr.sun_family = AF_UNIX;
    safe_strcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)-1);
    
    if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
        DEBUG(0, ("bind failed on winbind socket %s: %s\n",
                  path,
                  sys_errlist[errno]));
        close(sock);
        return -1;
    }
    
    if (listen(sock, 5) == -1) {
        DEBUG(0, ("listen failed on winbind socket %s: %s\n",
                  path,
                  sys_errlist[errno]));
        close(sock);
        return -1;
    }
    
    umask(old_umask);
    
    /* Success! */
    
    return sock;
}

static void process_request(struct winbindd_cli_state *state)
{
    /* Process command */

    state->response.result = WINBINDD_ERROR;
    state->response.length = sizeof(struct winbindd_response);

    DEBUG(3,("processing command %s from pid %d\n", 
            winbindd_cmd_to_string(state->request.cmd), state->pid));

    if (!server_state.lsa_handle_open) return;

    switch(state->request.cmd) {
        
        /* User functions */
        
    case WINBINDD_GETPWNAM_FROM_USER: 
        state->response.result = winbindd_getpwnam_from_user(state);
        break;
        
    case WINBINDD_GETPWNAM_FROM_UID:
        state->response.result = winbindd_getpwnam_from_uid(state);
        break;
        
    case WINBINDD_SETPWENT:
        state->response.result = winbindd_setpwent(state);
        break;
        
    case WINBINDD_ENDPWENT:
        state->response.result = winbindd_endpwent(state);
        break;
        
    case WINBINDD_GETPWENT:
        state->response.result = winbindd_getpwent(state);
        break;

        /* Group functions */
        
    case WINBINDD_GETGRNAM_FROM_GROUP:
        state->response.result = winbindd_getgrnam_from_group(state);
        break;
        
    case WINBINDD_GETGRNAM_FROM_GID:
        state->response.result = winbindd_getgrnam_from_gid(state);
        break;
        
    case WINBINDD_SETGRENT:
        state->response.result = winbindd_setgrent(state);
        break;
        
    case WINBINDD_ENDGRENT:
        state->response.result = winbindd_endgrent(state);
        break;
        
    case WINBINDD_GETGRENT:
        state->response.result = winbindd_getgrent(state);
        break;

	/* pam auth functions */
    case WINBINDD_PAM_AUTH:
        state->response.result = winbindd_pam_auth(state);
        break;

        /* Oops */
        
    default:
        DEBUG(0, ("oops - unknown winbindd command %d\n", state->request.cmd));
        break;
    }
}

/* Process a new connection by adding it to the client connection list */

static void new_connection(int accept_sock)
{
    struct sockaddr_un sunaddr;
    struct winbindd_cli_state *state;
    int len, sock;
    
    /* Accept connection */
    
    len = sizeof(sunaddr);
    if ((sock = accept(accept_sock, (struct sockaddr *)&sunaddr, &len)) 
        == -1) {
        
        return;
    }

    DEBUG(6,("accepted socket %d\n", sock));

    /* Create new connection structure */

    if ((state = (struct winbindd_cli_state *)
         malloc(sizeof(*state))) == NULL) {

        return;
    }

    ZERO_STRUCTP(state);
    state->sock = sock;

    /* Add to connection list */

    DLIST_ADD(client_list, state);
}

/* Remove a client connection from client connection list */

static void remove_client(struct winbindd_cli_state *state)
{
    /* It's a dead client - hold a funeral */

    if (state != NULL) {

        /* Close socket */

        close(state->sock);

        /* Free any getent state */

        free_getent_state(state->getpwent_state);
        free_getent_state(state->getgrent_state);

        /* Free any extra data */

        safe_free(state->response.extra_data);

        /* Remove from list and free */

        DLIST_REMOVE(client_list, state);
        free(state);
    }
}

/* Process a complete received packet from a client */

static void process_packet(struct winbindd_cli_state *state)
{
    /* Process request */

    state->pid = state->request.pid;

    process_request(state);

    /* Update client state */

    state->read_buf_len = 0;
    state->write_buf_len = sizeof(state->response);
}

/* Read some data from a client connection */

static void client_read(struct winbindd_cli_state *state)
{
    int n;
    
    /* Read data */

    n = read(state->sock, state->read_buf_len + (char *)&state->request, 
             sizeof(state->request) - state->read_buf_len);

    /* Read failed, kill client */

    if (n == -1 || n == 0) {
	    DEBUG(5,("read failed on sock %d, pid %d: %s\n",
                state->sock, state->pid, 
                (n == -1) ? sys_errlist[errno] : "EOF"));

        state->finished = True;
        return;
    }

    /* Update client state */

    state->read_buf_len += n;
}

/* Write some data to a client connection */

static void client_write(struct winbindd_cli_state *state)
{
    char *data;
    int n;

    /* Write data */

    if (state->write_extra_data) {

        /* Write extra data */

        data = (char *)state->response.extra_data + 
            state->response.length - sizeof(struct winbindd_response) - 
            state->write_buf_len;

    } else {

        /* Write response structure */

        data = (char *)&state->response + sizeof(state->response) - 
            state->write_buf_len;
    }

    n = write(state->sock, data, state->write_buf_len);

    /* Write failed, kill cilent */

    if (n == -1 || n == 0) {

	    DEBUG(3,("write failed on sock %d, pid %d: %s\n",
		     state->sock, state->pid, 
		     (n == -1) ? sys_errlist[errno] : "EOF"));

        state->finished = True;
        return;
    }

    /* Update client state */
    
    state->write_buf_len -= n;

    /* Have we written all data? */

    if (state->write_buf_len == 0) {

        /* Take care of extra data */

        if (state->response.length > sizeof(struct winbindd_response)) {

            if (state->write_extra_data) {

                /* Already written extra data - free it */

                safe_free(state->response.extra_data);
                state->response.extra_data = NULL;
                state->write_extra_data = False;

            } else {

                /* Start writing extra data */

                state->write_buf_len = state->response.length -
                    sizeof(struct winbindd_response);
                state->write_extra_data = True;
            }
        }
    }
}

/* Process incoming clients on accept_sock.  We use a tricky non-blocking,
   non-forking, non-threaded model which allows us to handle many
   simultaneous connections while remaining impervious to many denial of
   service attacks. */

static void process_loop(int accept_sock)
{
    /* We'll be doing this a lot */

    while (1) {
        struct winbindd_cli_state *state;
        fd_set r_fds, w_fds;
        int maxfd = accept_sock, selret;
	struct timeval timeout;

	/* do any connection establishment that is needed */
	establish_connections();	    

        /* Initialise fd lists for select() */

        FD_ZERO(&r_fds);
        FD_ZERO(&w_fds);
        FD_SET(accept_sock, &r_fds);

	timeout.tv_sec = WINBINDD_ESTABLISH_LOOP;
	timeout.tv_usec = 0;

        /* Set up client readers and writers */

        state = client_list;

        while (state) {
            /* Dispose of client connection if it is marked as finished */ 

            if (state->finished) {
                struct winbindd_cli_state *next = state->next;

                remove_client(state);
                state = next;
                continue;
            }

            /* Select requires we know the highest fd used */

            if (state->sock > maxfd) maxfd = state->sock;

            /* Add fd for reading */

            if (state->read_buf_len != sizeof(state->request)) {
                FD_SET(state->sock, &r_fds);
            }

            /* Add fd for writing */

            if (state->write_buf_len) {
                FD_SET(state->sock, &w_fds);
            }

            state = state->next;
        }

        /* Check signal handling things */

        if (flush_cache) {
            do_flush_caches();
            reload_services_file();
            flush_cache = False;
        }

        if (print_client_info) {
            do_print_client_info();
            print_client_info = False;
        }

        /* Call select */
        
        selret = select(maxfd + 1, &r_fds, &w_fds, NULL, &timeout);

	if (selret == 0) continue;

        if ((selret == -1 && errno != EINTR) || selret == 0) {

            /* Select error, something is badly wrong */

            perror("select");
            exit(1);
        }

        /* Create a new connection if accept_sock readable */

        if (selret > 0) {

            if (FD_ISSET(accept_sock, &r_fds)) {
                new_connection(accept_sock);
            }
            
            /* Process activity on client connections */
            
            for (state = client_list; state ; state = state->next) {
                
                /* Data available for reading */
                
                if (FD_ISSET(state->sock, &r_fds)) {
                    
                    /* Read data */
                    
                    client_read(state);
                    
                    /* A request packet might be complete */
                    
                    if (state->read_buf_len == sizeof(state->request)) {
                        process_packet(state);
                    }
                }
                
                /* Data available for writing */
                
                if (FD_ISSET(state->sock, &w_fds)) {
			client_write(state);
                }
            }
        }
    }
}

/* Main function */

struct winbindd_state server_state;   /* Server state information */

int main(int argc, char **argv)
{
    extern pstring global_myname;
    extern pstring debugf;
    int accept_sock;
    BOOL interactive = False;
    int opt;

    while ((opt = getopt(argc, argv, "i")) != EOF) {
	    switch (opt) {
		case 'i':
			interactive = True;
			break;
		default:
			printf("Unknown option %c (%d)\n", (char)opt, opt);
			exit(1);
		}
    }

    /* Initialise samba/rpc client stuff */
    slprintf(debugf, sizeof(debugf), "%s/log.winbindd", LOGFILEBASE);
    setup_logging("winbindd", interactive);
    reopen_logs();

    if (!*global_myname) {
        char *p;

        fstrcpy(global_myname, myhostname());
        p = strchr(global_myname, '.');
        if (p) {
            *p = 0;
        }
    }

    TimeInit();
    charset_initialise();
    codepage_initialise(lp_client_code_page());

    if (!lp_load(CONFIGFILE, True, False, False)) {
        DEBUG(0, ("error opening config file\n"));
        exit(1);
    }

    if (!interactive) {
	    become_daemon();
    }
    load_interfaces();

    secrets_init();

    ZERO_STRUCT(server_state);

    /* Winbind daemon initialisation */
    if (!winbindd_param_init()) {
	    return 1;
    }

    if (!winbindd_idmap_init()) {
        return 1;
    }

    winbindd_cache_init();

    /* Setup signal handlers */

    CatchSignal(SIGINT, termination_handler);         /* Exit on these sigs */
    CatchSignal(SIGQUIT, termination_handler);
    CatchSignal(SIGTERM, termination_handler);

    CatchSignal(SIGPIPE, SIG_IGN);                    /* Ignore sigpipe */

    CatchSignal(SIGUSR1, sigusr1_handler);            /* Debugging sigs */
    CatchSignal(SIGHUP, sighup_handler);

    /* Create UNIX domain socket */

    if ((accept_sock = create_sock()) == -1) {
        DEBUG(0, ("failed to create socket\n"));
        return 1;
    }

    /* Loop waiting for requests */

    process_loop(accept_sock);

    return 0;
}