bpo-32030: Add _Py_FindEnvConfigValue() (#4963)
Add a new _Py_FindEnvConfigValue() function: code shared between
Windows and Unix implementations of _PyPathConfig_Calculate() to read
the pyenv.cfg file.
_Py_FindEnvConfigValue() now uses _Py_DecodeUTF8_surrogateescape()
instead of using a Python Unicode string, the Python API must not be
used early during Python initialization. Same change in Unix
search_for_exec_prefix(): use _Py_DecodeUTF8_surrogateescape().
Cleanup also encode_current_locale(): PyMem_RawFree/PyMem_Free can be
called with NULL.
Fix also "NUL byte" => "NULL byte" typo.
diff --git a/Python/pathconfig.c b/Python/pathconfig.c
index acb25b6..9591fcc 100644
--- a/Python/pathconfig.c
+++ b/Python/pathconfig.c
@@ -354,6 +354,56 @@
return PyUnicode_FromWideChar(argv0, n);
}
+
+/* Search for a prefix value in an environment file (pyvenv.cfg).
+ If found, copy it into the provided buffer. */
+int
+_Py_FindEnvConfigValue(FILE *env_file, const wchar_t *key,
+ wchar_t *value, size_t value_size)
+{
+ int result = 0; /* meaning not found */
+ char buffer[MAXPATHLEN*2+1]; /* allow extra for key, '=', etc. */
+
+ fseek(env_file, 0, SEEK_SET);
+ while (!feof(env_file)) {
+ char * p = fgets(buffer, MAXPATHLEN*2, env_file);
+ wchar_t *tmpbuffer;
+ int n;
+
+ if (p == NULL) {
+ break;
+ }
+ n = strlen(p);
+ if (p[n - 1] != '\n') {
+ /* line has overflowed - bail */
+ break;
+ }
+ if (p[0] == '#') {
+ /* Comment - skip */
+ continue;
+ }
+ tmpbuffer = _Py_DecodeUTF8_surrogateescape(buffer, n, NULL);
+ if (tmpbuffer != NULL) {
+ wchar_t * state;
+ wchar_t * tok = wcstok(tmpbuffer, L" \t\r\n", &state);
+ if ((tok != NULL) && !wcscmp(tok, key)) {
+ tok = wcstok(NULL, L" \t", &state);
+ if ((tok != NULL) && !wcscmp(tok, L"=")) {
+ tok = wcstok(NULL, L"\r\n", &state);
+ if (tok != NULL) {
+ wcsncpy(value, tok, MAXPATHLEN);
+ result = 1;
+ PyMem_RawFree(tmpbuffer);
+ break;
+ }
+ }
+ }
+ PyMem_RawFree(tmpbuffer);
+ }
+ }
+ return result;
+}
+
#ifdef __cplusplus
}
#endif