mc/vfs/samba/lib/system.c

/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   Samba system utilities
   Copyright (C) Andrew Tridgell 1992-1998
   
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

#include "includes.h"

extern int DEBUGLEVEL;

/*
   The idea is that this file will eventually have wrappers around all
   important system calls in samba. The aims are:

   - to enable easier porting by putting OS dependent stuff in here

   - to allow for hooks into other "pseudo-filesystems"

   - to allow easier integration of things like the japanese extensions

   - to support the philosophy of Samba to expose the features of
     the OS within the SMB model. In general whatever file/printer/variable
     expansions/etc make sense to the OS should be acceptable to Samba.
*/


/*******************************************************************
this replaces the normal select() system call
return if some data has arrived on one of the file descriptors
return -1 means error
********************************************************************/
#ifndef HAVE_SELECT
static int pollfd(int fd)
{
  int     r=0;

#ifdef HAS_RDCHK
  r = rdchk(fd);
#elif defined(TCRDCHK)
  (void)ioctl(fd, TCRDCHK, &r);
#else
  (void)ioctl(fd, FIONREAD, &r);
#endif

  return(r);
}

int sys_select(int maxfd, fd_set *fds,struct timeval *tval)
{
  fd_set fds2;
  int counter=0;
  int found=0;

  FD_ZERO(&fds2);

  while (1) 
  {
    int i;
    for (i=0;i<maxfd;i++) {
      if (FD_ISSET(i,fds) && pollfd(i)>0) {
        found++;
        FD_SET(i,&fds2);
      }
    }

    if (found) {
      memcpy((void *)fds,(void *)&fds2,sizeof(fds2));
      return(found);
    }
      
    if (tval && tval->tv_sec < counter) return(0);
      sleep(1);
      counter++;
  }
}

#else /* !NO_SELECT */
int sys_select(int maxfd, fd_set *fds,struct timeval *tval)
{
#ifdef USE_POLL
  struct pollfd pfd[256];
  int i;
  int maxpoll;
  int timeout;
  int pollrtn;

  maxpoll = 0;
  for( i = 0; i < maxfd; i++) {
    if(FD_ISSET(i,fds)) {
      struct pollfd *pfdp = &pfd[maxpoll++];
      pfdp->fd = i;
      pfdp->events = POLLIN;
      pfdp->revents = 0;
    }
  }

  timeout = (tval != NULL) ? (tval->tv_sec * 1000) + (tval->tv_usec/1000) :
                -1;
  errno = 0;
  do {
    pollrtn = poll( &pfd[0], maxpoll, timeout);
  } while (pollrtn<0 && errno == EINTR);

  FD_ZERO(fds);

  for( i = 0; i < maxpoll; i++)
    if( pfd[i].revents & POLLIN )
      FD_SET(pfd[i].fd,fds);

  return pollrtn;
#else /* USE_POLL */

  struct timeval t2;
  int selrtn;

  do {
    if (tval) memcpy((void *)&t2,(void *)tval,sizeof(t2));
    errno = 0;
    selrtn = select(maxfd,SELECT_CAST fds,NULL,NULL,tval?&t2:NULL);
  } while (selrtn<0 && errno == EINTR);

  return(selrtn);
}
#endif /* USE_POLL */
#endif /* NO_SELECT */

/*******************************************************************
A stat() wrapper that will deal with 64 bit filesizes.
********************************************************************/

int sys_stat(const char *fname,SMB_STRUCT_STAT *sbuf)
{
  return stat(fname, sbuf);
}

/*******************************************************************
 An lstat() wrapper that will deal with 64 bit filesizes.
********************************************************************/
#if 0
int sys_lstat(const char *fname,SMB_STRUCT_STAT *sbuf)
{
  return lstat(fname, sbuf);
}

/*******************************************************************
 An fseek() wrapper that will deal with 64 bit filesizes.
********************************************************************/

int sys_fseek(FILE *fp, SMB_OFF_T offset, int whence)
{
  return fseek(fp, offset, whence);
}

/*******************************************************************
 An ftell() wrapper that will deal with 64 bit filesizes.
********************************************************************/

SMB_OFF_T sys_ftell(FILE *fp)
{
  return (SMB_OFF_T)ftell(fp);
}
#endif /* 0 */
/*******************************************************************
 An open() wrapper that will deal with 64 bit filesizes.
********************************************************************/

int sys_open(const char *path, int oflag, mode_t mode)
{
  return open(path, oflag, mode);
}

/*******************************************************************
 An fopen() wrapper that will deal with 64 bit filesizes.
********************************************************************/

FILE *sys_fopen(const char *path, const char *type)
{
  return fopen(path, type);
}
#if 0
/*******************************************************************
 A readdir wrapper that will deal with 64 bit filesizes.
********************************************************************/

SMB_STRUCT_DIRENT *sys_readdir(DIR *dirp)
{
  return readdir(dirp);
}

/*******************************************************************
system wrapper for getwd
********************************************************************/
char *sys_getwd(char *s)
{
    char *wd;
#ifdef HAVE_GETCWD
    wd = (char *)getcwd(s, sizeof (pstring));
#else
    wd = (char *)getwd(s);
#endif
    return wd;
}

/*******************************************************************
chown isn't used much but OS/2 doesn't have it
********************************************************************/

int sys_chown(const char *fname,uid_t uid,gid_t gid)
{
#ifndef HAVE_CHOWN
	static int done;
	if (!done) {
		DEBUG(1,("WARNING: no chown!\n"));
		done=1;
	}
#else
	return(chown(fname,uid,gid));
#endif
}
#endif /* 0 */
/**************************************************************************
A wrapper for gethostbyname() that tries avoids looking up hostnames 
in the root domain, which can cause dial-on-demand links to come up for no
apparent reason.
****************************************************************************/
struct hostent *sys_gethostbyname(const char *name)
{
#ifdef REDUCE_ROOT_DNS_LOOKUPS
  char query[256], hostname[256];
  char *domain;

  /* Does this name have any dots in it? If so, make no change */

  if (strchr(name, '.'))
    return(gethostbyname(name));

  /* Get my hostname, which should have domain name 
     attached. If not, just do the gethostname on the
     original string. 
  */

  gethostname(hostname, sizeof(hostname) - 1);
  hostname[sizeof(hostname) - 1] = 0;
  if ((domain = strchr(hostname, '.')) == NULL)
    return(gethostbyname(name));

  /* Attach domain name to query and do modified query.
     If names too large, just do gethostname on the
     original string.
  */

  if((strlen(name) + strlen(domain)) >= sizeof(query))
    return(gethostbyname(name));

  slprintf(query, sizeof(query)-1, "%s%s", name, domain);
  return(gethostbyname(query));
#else /* REDUCE_ROOT_DNS_LOOKUPS */
  return(gethostbyname(name));
#endif /* REDUCE_ROOT_DNS_LOOKUPS */
}

/**************************************************************************
 Wrapper for random().
****************************************************************************/
#if 0
long sys_random(void)
{
#if defined(HAVE_RANDOM)
  return (long)random();
#elif defined(HAVE_RAND)
  return (long)rand();
#else
  DEBUG(0,("Error - no random function available !\n"));
  exit(1);
#endif
}

/**************************************************************************
 Wrapper for srandom().
****************************************************************************/

void sys_srandom(unsigned int seed)
{
#if defined(HAVE_SRANDOM)
  srandom(seed);
#elif defined(HAVE_SRAND)
  srand(seed);
#else
  DEBUG(0,("Error - no srandom function available !\n"));
  exit(1);
#endif
}
#endif /* 0 */