1  /* shm_open -- open a POSIX shared memory object.  Generic POSIX file version.
       2     Copyright (C) 2001-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <errno.h>
      20  #include <fcntl.h>
      21  #include <not-cancel.h>
      22  #include <pthread.h>
      23  #include <shlib-compat.h>
      24  #include <shm-directory.h>
      25  #include <unistd.h>
      26  #include <sys/mman.h>
      27  
      28  /* Open shared memory object.  */
      29  int
      30  __shm_open (const char *name, int oflag, mode_t mode)
      31  {
      32    struct shmdir_name dirname;
      33    int ret =__shm_get_name (&dirname, name, false);
      34    if (ret != 0)
      35      {
      36        __set_errno (ret);
      37        return -1;
      38      }
      39  
      40    oflag |= O_NOFOLLOW | O_CLOEXEC;
      41  #if defined (SHM_ANON) && defined (O_TMPFILE)
      42    if (name == SHM_ANON)
      43      oflag |= O_TMPFILE;
      44  #endif
      45  
      46    int fd = __open64_nocancel (dirname.name, oflag, mode);
      47    if (fd == -1 && __glibc_unlikely (errno == EISDIR))
      48      /* It might be better to fold this error with EINVAL since
      49         directory names are just another example for unsuitable shared
      50         object names and the standard does not mention EISDIR.  */
      51      __set_errno (EINVAL);
      52  
      53    return fd;
      54  }
      55  versioned_symbol (libc, __shm_open, shm_open, GLIBC_2_34);
      56  
      57  #if OTHER_SHLIB_COMPAT (librt, GLIBC_2_2, GLIBC_2_34)
      58  compat_symbol (libc, __shm_open, shm_open, GLIBC_2_2);
      59  #endif