text: /* shm_open -- open a POSIX shared memory object.  Generic POSIX file version.
     Copyright (C) 2001,2002,2005 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C 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
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, see
     <http://www.gnu.org/licenses/>.  */
  
  #include <unistd.h>
  
  #if ! _POSIX_MAPPED_FILES
  #include <rt/shm_open.c>
  
  #else
  
  #include <errno.h>
  #include <sys/mman.h>
  #include <fcntl.h>
  #include <string.h>
  #include <stdlib.h>
  #include <paths.h>
  
  #define SHMDIR	(_PATH_DEV "shm/")
  
  /* Open shared memory object.  */
  int
  shm_open (const char *name, int oflag, mode_t mode)
  {
    size_t namelen;
    char *fname;
    int fd;
  
    /* Construct the filename.  */
    while (name[0] == '/')
      ++name;
  
    if (name[0] == '\0')
      {
        /* The name "/" is not supported.  */
        __set_errno (EINVAL);
        return -1;
      }
  
    namelen = strlen (name);
    fname = (char *) __alloca (sizeof SHMDIR - 1 + namelen + 1);
    __mempcpy (__mempcpy (fname, SHMDIR, sizeof SHMDIR - 1),
  	     name, namelen + 1);
  
    fd = open (name, oflag, mode);
    if (fd != -1)
      {
        /* We got a descriptor.  Now set the FD_CLOEXEC bit.  */
        int flags = fcntl (fd, F_GETFD, 0);
  
        if (__builtin_expect (flags, 0) != -1)
  	{
  	  flags |= FD_CLOEXEC;
  	  flags = fcntl (fd, F_SETFD, flags);
  	}
  
        if (flags == -1)
  	{
  	  /* Something went wrong.  We cannot return the descriptor.  */
  	  int save_errno = errno;
  	  close (fd);
  	  fd = -1;
  	  __set_errno (save_errno);
  	}
      }
  
    return fd;
  }
  
  #endif
  