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wb_common.c

/* 
   Unix SMB/CIFS implementation.

   winbind client common code

   Copyright (C) Tim Potter 2000
   Copyright (C) Andrew Tridgell 2000
   
   This 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.
   
   This 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 this library; if not, write to the
   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA  02111-1307, USA.   
*/

#include "winbind_nss_config.h"
#include "winbindd_nss.h"

/* Global variables.  These are effectively the client state information */

int winbindd_fd = -1;           /* fd for winbindd socket */
static char *excluded_domain;

/* Free a response structure */

void free_response(struct winbindd_response *response)
{
      /* Free any allocated extra_data */

      if (response)
            SAFE_FREE(response->extra_data);
}

/*
  smbd needs to be able to exclude lookups for its own domain
*/
void winbind_exclude_domain(const char *domain)
{
      SAFE_FREE(excluded_domain);
      excluded_domain = strdup(domain);
}


/* Initialise a request structure */

void init_request(struct winbindd_request *request, int request_type)
{
        static char *domain_env;
        static BOOL initialised;

      request->length = sizeof(struct winbindd_request);

      request->cmd = (enum winbindd_cmd)request_type;
      request->pid = getpid();
      request->domain[0] = '\0';

      if (!initialised) {
            initialised = True;
            domain_env = getenv(WINBINDD_DOMAIN_ENV);
      }

      if (domain_env) {
            strncpy(request->domain, domain_env,
                  sizeof(request->domain) - 1);
            request->domain[sizeof(request->domain) - 1] = '\0';
      }
}

/* Initialise a response structure */

void init_response(struct winbindd_response *response)
{
      /* Initialise return value */

      response->result = WINBINDD_ERROR;
}

/* Close established socket */

void close_sock(void)
{
      if (winbindd_fd != -1) {
            close(winbindd_fd);
            winbindd_fd = -1;
      }
}

/* Connect to winbindd socket */

int winbind_open_pipe_sock(void)
{
      struct sockaddr_un sunaddr;
      static pid_t our_pid;
      struct stat st;
      pstring path;
      
      if (our_pid != getpid()) {
            close_sock();
            our_pid = getpid();
      }
      
      if (winbindd_fd != -1) {
            return winbindd_fd;
      }
      
      /* Check permissions on unix socket directory */
      
      if (lstat(WINBINDD_SOCKET_DIR, &st) == -1) {
            return -1;
      }
      
      if (!S_ISDIR(st.st_mode) || 
          (st.st_uid != 0 && st.st_uid != geteuid())) {
            return -1;
      }
      
      /* Connect to socket */
      
      strncpy(path, WINBINDD_SOCKET_DIR, sizeof(path) - 1);
      path[sizeof(path) - 1] = '\0';
      
      strncat(path, "/", sizeof(path) - 1);
      path[sizeof(path) - 1] = '\0';
      
      strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1);
      path[sizeof(path) - 1] = '\0';
      
      ZERO_STRUCT(sunaddr);
      sunaddr.sun_family = AF_UNIX;
      strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
      
      /* If socket file doesn't exist, don't bother trying to connect
         with retry.  This is an attempt to make the system usable when
         the winbindd daemon is not running. */

      if (lstat(path, &st) == -1) {
            return -1;
      }
      
      /* Check permissions on unix socket file */
      
      if (!S_ISSOCK(st.st_mode) || 
          (st.st_uid != 0 && st.st_uid != geteuid())) {
            return -1;
      }
      
      /* Connect to socket */
      
      if ((winbindd_fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
            return -1;
      }
      
      if (connect(winbindd_fd, (struct sockaddr *)&sunaddr, 
                sizeof(sunaddr)) == -1) {
            close_sock();
            return -1;
      }
        
      return winbindd_fd;
}

/* Write data to winbindd socket */

int write_sock(void *buffer, int count)
{
      int result, nwritten;
      
      /* Open connection to winbind daemon */
      
 restart:
      
      if (winbind_open_pipe_sock() == -1) {
            return -1;
      }
      
      /* Write data to socket */
      
      nwritten = 0;
      
      while(nwritten < count) {
            struct timeval tv;
            fd_set r_fds;
            
            /* Catch pipe close on other end by checking if a read()
               call would not block by calling select(). */

            FD_ZERO(&r_fds);
            FD_SET(winbindd_fd, &r_fds);
            ZERO_STRUCT(tv);
            
            if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
                  close_sock();
                  return -1;                   /* Select error */
            }
            
            /* Write should be OK if fd not available for reading */
            
            if (!FD_ISSET(winbindd_fd, &r_fds)) {
                  
                  /* Do the write */
                  
                  result = write(winbindd_fd,
                               (char *)buffer + nwritten, 
                               count - nwritten);
                  
                  if ((result == -1) || (result == 0)) {
                        
                        /* Write failed */
                        
                        close_sock();
                        return -1;
                  }
                  
                  nwritten += result;
                  
            } else {
                  
                  /* Pipe has closed on remote end */
                  
                  close_sock();
                  goto restart;
            }
      }
      
      return nwritten;
}

/* Read data from winbindd socket */

static int read_sock(void *buffer, int count)
{
      int result = 0, nread = 0;

      /* Read data from socket */
      
      while(nread < count) {
            
            result = read(winbindd_fd, (char *)buffer + nread, 
                        count - nread);
            
            if ((result == -1) || (result == 0)) {
                  
                  /* Read failed.  I think the only useful thing we
                     can do here is just return -1 and fail since the
                     transaction has failed half way through. */
                  
                  close_sock();
                  return -1;
            }
            
            nread += result;
      }
      
      return result;
}

/* Read reply */

int read_reply(struct winbindd_response *response)
{
      int result1, result2 = 0;

      if (!response) {
            return -1;
      }
      
      /* Read fixed length response */
      
      if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
          == -1) {
            
            return -1;
      }
      
      /* We actually send the pointer value of the extra_data field from
         the server.  This has no meaning in the client's address space
         so we clear it out. */

      response->extra_data = NULL;

      /* Read variable length response */
      
      if (response->length > sizeof(struct winbindd_response)) {
            int extra_data_len = response->length - 
                  sizeof(struct winbindd_response);
            
            /* Mallocate memory for extra data */
            
            if (!(response->extra_data = (void *)malloc(extra_data_len))) {
                  return -1;
            }
            
            if ((result2 = read_sock(response->extra_data, extra_data_len))
                == -1) {
                  free_response(response);
                  return -1;
            }
      }
      
      /* Return total amount of data read */
      
      return result1 + result2;
}

/* 
 * send simple types of requests 
 */

NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
{
      struct winbindd_request lrequest;

      /* Check for our tricky environment variable */

      if (getenv(WINBINDD_DONT_ENV)) {
            return NSS_STATUS_NOTFOUND;
      }

      /* smbd may have excluded this domain */
      if (excluded_domain && 
          strcasecmp(excluded_domain, request->domain) == 0) {
            return NSS_STATUS_NOTFOUND;
      }

      if (!request) {
            ZERO_STRUCT(lrequest);
            request = &lrequest;
      }
      
      /* Fill in request and send down pipe */

      init_request(request, req_type);
      
      if (write_sock(request, sizeof(*request)) == -1) {
            return NSS_STATUS_UNAVAIL;
      }
      
      return NSS_STATUS_SUCCESS;
}

/*
 * Get results from winbindd request
 */

NSS_STATUS winbindd_get_response(struct winbindd_response *response)
{
      struct winbindd_response lresponse;

      if (!response) {
            ZERO_STRUCT(lresponse);
            response = &lresponse;
      }

      init_response(response);

      /* Wait for reply */
      if (read_reply(response) == -1) {
            return NSS_STATUS_UNAVAIL;
      }

      /* Throw away extra data if client didn't request it */
      if (response == &lresponse) {
            free_response(response);
      }

      /* Copy reply data from socket */
      if (response->result != WINBINDD_OK) {
            return NSS_STATUS_NOTFOUND;
      }
      
      return NSS_STATUS_SUCCESS;
}

/* Handle simple types of requests */

NSS_STATUS winbindd_request(int req_type, 
                         struct winbindd_request *request,
                         struct winbindd_response *response)
{
      NSS_STATUS status;

      status = winbindd_send_request(req_type, request);
      if (status != NSS_STATUS_SUCCESS) 
            return(status);
      return winbindd_get_response(response);
}

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