1  /*
       2  posixshmem - A Python extension that provides shm_open() and shm_unlink()
       3  */
       4  
       5  #define PY_SSIZE_T_CLEAN
       6  
       7  #include <Python.h>
       8  
       9  // for shm_open() and shm_unlink()
      10  #ifdef HAVE_SYS_MMAN_H
      11  #include <sys/mman.h>
      12  #endif
      13  
      14  /*[clinic input]
      15  module _posixshmem
      16  [clinic start generated code]*/
      17  /*[clinic end generated code: output=da39a3ee5e6b4b0d input=a416734e49164bf8]*/
      18  
      19  /*
      20   *
      21   * Module-level functions & meta stuff
      22   *
      23   */
      24  
      25  #ifdef HAVE_SHM_OPEN
      26  /*[clinic input]
      27  _posixshmem.shm_open -> int
      28      path: unicode
      29      flags: int
      30      mode: int = 0o777
      31  
      32  # "shm_open(path, flags, mode=0o777)\n\n\
      33  
      34  Open a shared memory object.  Returns a file descriptor (integer).
      35  
      36  [clinic start generated code]*/
      37  
      38  static int
      39  _posixshmem_shm_open_impl(PyObject *module, PyObject *path, int flags,
      40                            int mode)
      41  /*[clinic end generated code: output=8d110171a4fa20df input=e83b58fa802fac25]*/
      42  {
      43      int fd;
      44      int async_err = 0;
      45      const char *name = PyUnicode_AsUTF8(path);
      46      if (name == NULL) {
      47          return -1;
      48      }
      49      do {
      50          Py_BEGIN_ALLOW_THREADS
      51          fd = shm_open(name, flags, mode);
      52          Py_END_ALLOW_THREADS
      53      } while (fd < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
      54  
      55      if (fd < 0) {
      56          if (!async_err)
      57              PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
      58          return -1;
      59      }
      60  
      61      return fd;
      62  }
      63  #endif /* HAVE_SHM_OPEN */
      64  
      65  #ifdef HAVE_SHM_UNLINK
      66  /*[clinic input]
      67  _posixshmem.shm_unlink
      68      path: unicode
      69  
      70  Remove a shared memory object (similar to unlink()).
      71  
      72  Remove a shared memory object name, and, once all processes  have  unmapped
      73  the object, de-allocates and destroys the contents of the associated memory
      74  region.
      75  
      76  [clinic start generated code]*/
      77  
      78  static PyObject *
      79  _posixshmem_shm_unlink_impl(PyObject *module, PyObject *path)
      80  /*[clinic end generated code: output=42f8b23d134b9ff5 input=8dc0f87143e3b300]*/
      81  {
      82      int rv;
      83      int async_err = 0;
      84      const char *name = PyUnicode_AsUTF8(path);
      85      if (name == NULL) {
      86          return NULL;
      87      }
      88      do {
      89          Py_BEGIN_ALLOW_THREADS
      90          rv = shm_unlink(name);
      91          Py_END_ALLOW_THREADS
      92      } while (rv < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
      93  
      94      if (rv < 0) {
      95          if (!async_err)
      96              PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
      97          return NULL;
      98      }
      99  
     100      Py_RETURN_NONE;
     101  }
     102  #endif /* HAVE_SHM_UNLINK */
     103  
     104  #include "clinic/posixshmem.c.h"
     105  
     106  static PyMethodDef module_methods[ ] = {
     107      _POSIXSHMEM_SHM_OPEN_METHODDEF
     108      _POSIXSHMEM_SHM_UNLINK_METHODDEF
     109      {NULL} /* Sentinel */
     110  };
     111  
     112  
     113  static PyModuleDef_Slot module_slots[] = {
     114      {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
     115      {0, NULL}
     116  };
     117  
     118  
     119  static struct PyModuleDef _posixshmemmodule = {
     120      PyModuleDef_HEAD_INIT,
     121      .m_name = "_posixshmem",
     122      .m_doc = "POSIX shared memory module",
     123      .m_size = 0,
     124      .m_methods = module_methods,
     125      .m_slots = module_slots,
     126  };
     127  
     128  /* Module init function */
     129  PyMODINIT_FUNC
     130  PyInit__posixshmem(void)
     131  {
     132      return PyModuleDef_Init(&_posixshmemmodule);
     133  }