lib/util/blocking.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 2001-2002
   6    Copyright (C) Simo Sorce 2001
   7    Copyright (C) Jim McDonough (jmcd@us.ibm.com)  2003.
   8    Copyright (C) James J Myers 2003
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "replace.h"
  25 #include "system/filesys.h"
  26 #include "blocking.h"
  27
  28 /**
  29  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
  30  else
  31   if SYSV use O_NDELAY
  32   if BSD use FNDELAY
  33 **/
  34
  35 _PUBLIC_ int set_blocking(int fd, bool set)
  36 {
  37         int val;
  38 #ifdef O_NONBLOCK
  39 #define FLAG_TO_SET O_NONBLOCK
  40 #else
  41 #ifdef SYSV
  42 #define FLAG_TO_SET O_NDELAY
  43 #else /* BSD */
  44 #define FLAG_TO_SET FNDELAY
  45 #endif
  46 #endif
  47
  48         if((val = fcntl(fd, F_GETFL, 0)) == -1)
  49                 return -1;
  50         if(set) /* Turn blocking on - ie. clear nonblock flag */
  51                 val &= ~FLAG_TO_SET;
  52         else
  53                 val |= FLAG_TO_SET;
  54         return fcntl( fd, F_SETFL, val);
  55 #undef FLAG_TO_SET
  56 }
  57
  58
  59 _PUBLIC_ bool smb_set_close_on_exec(int fd)
  60 {
  61 #ifdef FD_CLOEXEC
  62         int val;
  63
  64         val = fcntl(fd, F_GETFD, 0);
  65         if (val >= 0) {
  66                 val |= FD_CLOEXEC;
  67                 val = fcntl(fd, F_SETFD, val);
  68                 if (val != -1) {
  69                         return true;
  70                 }
  71         }
  72 #else
  73         errno = ENOSYS;
  74 #endif
  75         return false;
  76 }