1 diff --git Python-2.6.4/Python/import.c Python-2.6.4/Python/import.c

     2 --- Python-2.6.4/Python/import.c

     3 +++ Python-2.6.4/Python/import.c

     4 @@ -868,8 +868,9 @@

     5  

     6  /* Write a compiled module to a file, placing the time of last

     7     modification of its source into the header.

     8 -   Errors are ignored, if a write error occurs an attempt is made to

     9 -   remove the file. */

    10 +   Write to a temporary file first so that creating the file is atomic.

    11 +   Errors are ignored, if a write/unlink/rename error occurs an attempt

    12 +   is made to remove the temporary file. */

    13  

    14  static void

    15  write_compiled_module(PyCodeObject *co, char *cpathname, struct stat *srcstat)

    16 @@ -882,11 +883,21 @@

    17      mode_t mode = srcstat->st_mode & ~S_IXUSR & ~S_IXGRP & ~S_IXOTH;

    18  #endif

    19  

    20 -    fp = open_exclusive(cpathname, mode);

    21 +    char *tmppathname;

    22 +

    23 +    /* the temporary file is called cpathname + ".tmp" */

    24 +    if ((tmppathname = PyMem_Malloc(strlen(cpathname) + strlen(".tmp") + 1))

    25 +        == NULL) {

    26 +        return;

    27 +    }

    28 +    sprintf (tmppathname, "%s.tmp", cpathname);

    29 +    fp = open_exclusive(tmppathname, mode);

    30 +

    31      if (fp == NULL) {

    32          if (Py_VerboseFlag)

    33              PySys_WriteStderr(

    34 -                "# can't create %s\n", cpathname);

    35 +                "# can't create %s\n", tmppathname);

    36 +        PyMem_Free(tmppathname);

    37          return;

    38      }

    39      PyMarshal_WriteLongToFile(pyc_magic, fp, Py_MARSHAL_VERSION);

    40 @@ -895,10 +906,11 @@

    41      PyMarshal_WriteObjectToFile((PyObject *)co, fp, Py_MARSHAL_VERSION);

    42      if (fflush(fp) != 0 || ferror(fp)) {

    43          if (Py_VerboseFlag)

    44 -            PySys_WriteStderr("# can't write %s\n", cpathname);

    45 +            PySys_WriteStderr("# can't write %s\n", tmppathname);

    46          /* Don't keep partial file */

    47          fclose(fp);

    48 -        (void) unlink(cpathname);

    49 +        (void) unlink(tmppathname);

    50 +        PyMem_Free(tmppathname);

    51          return;

    52      }

    53      /* Now write the true mtime */

    54 @@ -907,8 +919,29 @@

    55      PyMarshal_WriteLongToFile((long)mtime, fp, Py_MARSHAL_VERSION);

    56      fflush(fp);

    57      fclose(fp);

    58 +    /* Delete the old compiled file, if exists */

    59 +    if (unlink (cpathname)) {

    60 +        if ((errno != ENOENT)) {

    61 +            /* the file exists but could not be deleted */

    62 +            if (Py_VerboseFlag)

    63 +                PySys_WriteStderr("# can't unlink %s\n", cpathname);

    64 +            (void) unlink(tmppathname);

    65 +            PyMem_Free(tmppathname);

    66 +            return;

    67 +        }

    68 +    }

    69 +    /* rename the tmp file to the real file name */

    70 +    if (rename (tmppathname, cpathname)) {

    71 +        if (Py_VerboseFlag)

    72 +            PySys_WriteStderr(

    73 +                "# can't rename %s to %s\n", tmppathname, cpathname);

    74 +        (void) unlink(tmppathname);

    75 +        PyMem_Free(tmppathname);

    76 +        return;

    77 +    }

    78      if (Py_VerboseFlag)

    79          PySys_WriteStderr("# wrote %s\n", cpathname);

    80 +    PyMem_Free(tmppathname);

    81  }

    82  

    83  static void