system.c

MC Linux/Unix 终端下文件管理器

/* 
   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., 675 Mass Ave, Cambridge, MA 02139, 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 wrapper for usleep in case we don't have one.
********************************************************************/

int sys_usleep(long usecs)
{
#ifndef HAVE_USLEEP
  struct timeval tval;
#endif

  /*
   * We need this braindamage as the glibc usleep
   * is not SPEC1170 complient... grumble... JRA.
   */

  if(usecs < 0 || usecs > 1000000) {
    errno = EINVAL;
    return -1;
  }

#if HAVE_USLEEP
  usleep(usecs);
  return 0;
#else /* HAVE_USLEEP */
  /*
   * Fake it with select...
   */
  tval.tv_sec = 0;
  tval.tv_usec = usecs/1000;
  select(0,NULL,NULL,NULL,&tval);
  return 0;
#endif /* HAVE_USLEEP */
}

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

int sys_fstat(int fd,SMB_STRUCT_STAT *sbuf)
{
  return fstat(fd, sbuf);
}

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

int sys_lstat(const char *fname,SMB_STRUCT_STAT *sbuf)
{
  return lstat(fname, sbuf);
}

/*******************************************************************
 An ftruncate() wrapper that will deal with 64 bit filesizes.
********************************************************************/
#if 0
int sys_ftruncate(int fd, SMB_OFF_T offset)
{
  return ftruncate(fd, offset);
}
#endif
/*******************************************************************
 An lseek() wrapper that will deal with 64 bit filesizes.
********************************************************************/

SMB_OFF_T sys_lseek(int fd, SMB_OFF_T offset, int whence)
{
  return lseek(fd, offset, whence);
}

/*******************************************************************
 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);
}

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

int sys_creat(const char *path, mode_t mode)
{
  return sys_open(path, O_WRONLY | O_CREAT | O_TRUNC, mode);
}

/*******************************************************************
 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 defined(HAVE_MMAP)

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

void *sys_mmap(void *addr, size_t len, int prot, int flags, int fd, SMB_OFF_T offset)
{
  return mmap(addr, len, prot, flags, fd, offset);
}

#endif /* HAVE_MMAP */

/*******************************************************************
 A readdir wrapper that will deal with 64 bit filesizes.
********************************************************************/

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

/*******************************************************************
The wait() calls vary between systems
********************************************************************/
#if 0
int sys_waitpid(pid_t pid,int *status,int options)
{
#ifdef HAVE_WAITPID
  return waitpid(pid,status,options);
#else /* HAVE_WAITPID */
  return wait4(pid, status, options, NULL);
#endif /* HAVE_WAITPID */
}
#endif
/*******************************************************************
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
}

/**************************************************************************
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 */
}


/**************************************************************************
 Try and abstract process capabilities (for systems that have them).
****************************************************************************/

BOOL set_process_capability( uint32 cap_flag, BOOL enable )
{
#if defined(HAVE_IRIX_SPECIFIC_CAPABILITIES)
  if(cap_flag == KERNEL_OPLOCK_CAPABILITY)
  {
    cap_t cap = cap_get_proc();

    if (cap == NULL) {
      DEBUG(0,("set_process_capability: cap_get_proc failed. Error was %s\n",
            strerror(errno)));
      return False;
    }

    if(enable)
      cap->cap_effective |= CAP_NETWORK_MGT;
    else
      cap->cap_effective &= ~CAP_NETWORK_MGT;

    if (cap_set_proc(cap) == -1) {
      DEBUG(0,("set_process_capability: cap_set_proc failed. Error was %s\n",
            strerror(errno)));
      cap_free(cap);
      return False;
    }

    cap_free(cap);

    DEBUG(10,("set_process_capability: Set KERNEL_OPLOCK_CAPABILITY.\n"));
  }
#endif
  return True;
}

/**************************************************************************
 Try and abstract inherited process capabilities (for systems that have them).
****************************************************************************/

BOOL set_inherited_process_capability( uint32 cap_flag, BOOL enable )
{
#if defined(HAVE_IRIX_SPECIFIC_CAPABILITIES)
  if(cap_flag == KERNEL_OPLOCK_CAPABILITY)
  {
    cap_t cap = cap_get_proc();

    if (cap == NULL) {
      DEBUG(0,("set_inherited_process_capability: cap_get_proc failed. Error was %s\n",
            strerror(errno)));
      return False;
    }

    if(enable)
      cap->cap_inheritable |= CAP_NETWORK_MGT;
    else
      cap->cap_inheritable &= ~CAP_NETWORK_MGT;

    if (cap_set_proc(cap) == -1) {
      DEBUG(0,("set_inherited_process_capability: cap_set_proc failed. Error was %s\n", 
            strerror(errno)));
      cap_free(cap);
      return False;
    }

    cap_free(cap);

    DEBUG(10,("set_inherited_process_capability: Set KERNEL_OPLOCK_CAPABILITY.\n"));
  }
#endif
  return True;
}

/**************************************************************************
 Wrapper for random().
****************************************************************************/

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
}

/**************************************************************************
 Wrapper for getgroups. Deals with broken (int) case.
****************************************************************************/

int sys_getgroups(int setlen, gid_t *gidset)
{
#if !defined(HAVE_BROKEN_GETGROUPS)
  return getgroups(setlen, gidset);
#else

  GID_T gid;
  GID_T *group_list;
  int i, ngroups;

  if(setlen == 0) {
    return getgroups(setlen, &gid);
  }

  /*
   * Broken case. We need to allocate a
   * GID_T array of size setlen.
   */

  if(setlen < 0) {
    errno = EINVAL; 
    return -1;
  } 

  if (setlen == 0)
    setlen = 1;

  if((group_list = (GID_T *)malloc(setlen * sizeof(GID_T))) == NULL) {
    DEBUG(0,("sys_getgroups: Malloc fail.\n"));
    return -1;
  }

  if((ngroups = getgroups(setlen, group_list)) < 0) {
    int saved_errno = errno;
    free((char *)group_list);
    errno = saved_errno;
    return -1;
  }

  for(i = 0; i < ngroups; i++)
    gidset[i] = (gid_t)group_list[i];

  free((char *)group_list);
  return ngroups;
#endif /* HAVE_BROKEN_GETGROUPS */
}

#ifdef HAVE_SETGROUPS

/**************************************************************************
 Wrapper for setgroups. Deals with broken (int) case. Automatically used
 if we have broken getgroups.
****************************************************************************/

int sys_setgroups(int setlen, gid_t *gidset)
{
#if !defined(HAVE_BROKEN_GETGROUPS)
  return setgroups(setlen, gidset);
#else

  GID_T *group_list;
  int i ; 

  if (setlen == 0)
    return 0 ;

#ifdef NGROUPS_MAX
  if (setlen > NGROUPS_MAX) {
    errno = EINVAL; 
    return -1;   
  }
#endif

  /*
   * Broken case. We need to allocate a
   * GID_T array of size setlen.
   */

  if (setlen == 0)
    setlen = 1;

  if((group_list = (GID_T *)malloc(setlen * sizeof(GID_T))) == NULL) {
    DEBUG(0,("sys_setgroups: Malloc fail.\n"));
    return -1;    
  }
 
  for(i = 0; i < setlen; i++) 
    group_list[i] = (GID_T) gidset[i]; 

  if(setgroups(setlen, group_list) != 0) {
    int saved_errno = errno;
    free((char *)group_list);
    errno = saved_errno;
    return -1;
  }
 
  free((char *)group_list);
  return 0 ;
#endif /* HAVE_BROKEN_GETGROUPS */
}

#endif /* HAVE_SETGROUPS */