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bpo-36387: Refactor getenvironment() in _winapi.c. #12482

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Merged
serhiy-storchaka merged 1 commit into from
Mar 28, 2019
Merged

bpo-36387: Refactor getenvironment() in _winapi.c. #12482

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80 changes: 34 additions & 46 deletions Modules/_winapi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -752,12 +752,12 @@ gethandle(PyObject* obj, const char* name)
return ret;
}

static PyObject*
static wchar_t *
getenvironment(PyObject* environment)
{
Py_ssize_t i, envsize, totalsize;
Py_UCS4 *buffer = NULL, *p, *end;
PyObject *keys, *values, *res;
wchar_t *buffer = NULL, *p, *end;
PyObject *keys, *values;

/* convert environment dictionary to windows environment string */
if (! PyMapping_Check(environment)) {
Expand All @@ -775,17 +775,18 @@ getenvironment(PyObject* environment)
goto error;
}

envsize = PySequence_Fast_GET_SIZE(keys);
if (PySequence_Fast_GET_SIZE(values) != envsize) {
envsize = PyList_GET_SIZE(keys);
if (PyList_GET_SIZE(values) != envsize) {
PyErr_SetString(PyExc_RuntimeError,
"environment changed size during iteration");
goto error;
}

totalsize = 1; /* trailing null character */
for (i = 0; i < envsize; i++) {
PyObject* key = PySequence_Fast_GET_ITEM(keys, i);
PyObject* value = PySequence_Fast_GET_ITEM(values, i);
PyObject* key = PyList_GET_ITEM(keys, i);
PyObject* value = PyList_GET_ITEM(values, i);
Py_ssize_t size;

if (! PyUnicode_Check(key) || ! PyUnicode_Check(value)) {
PyErr_SetString(PyExc_TypeError,
Expand All @@ -806,19 +807,25 @@ getenvironment(PyObject* environment)
PyErr_SetString(PyExc_ValueError, "illegal environment variable name");
goto error;
}
if (totalsize > PY_SSIZE_T_MAX - PyUnicode_GET_LENGTH(key) - 1) {

size = PyUnicode_AsWideChar(key, NULL, 0);
assert(size > 1);
if (totalsize > PY_SSIZE_T_MAX - size) {
PyErr_SetString(PyExc_OverflowError, "environment too long");
goto error;
}
totalsize += PyUnicode_GET_LENGTH(key) + 1; /* +1 for '=' */
if (totalsize > PY_SSIZE_T_MAX - PyUnicode_GET_LENGTH(value) - 1) {
totalsize += size; /* including '=' */

size = PyUnicode_AsWideChar(value, NULL, 0);
assert(size > 0);
if (totalsize > PY_SSIZE_T_MAX - size) {
PyErr_SetString(PyExc_OverflowError, "environment too long");
goto error;
}
totalsize += PyUnicode_GET_LENGTH(value) + 1; /* +1 for '\0' */
totalsize += size; /* including trailing '\0' */
}

buffer = PyMem_NEW(Py_UCS4, totalsize);
buffer = PyMem_NEW(wchar_t, totalsize);
if (! buffer) {
PyErr_NoMemory();
goto error;
Expand All @@ -827,34 +834,25 @@ getenvironment(PyObject* environment)
end = buffer + totalsize;

for (i = 0; i < envsize; i++) {
PyObject* key = PySequence_Fast_GET_ITEM(keys, i);
PyObject* value = PySequence_Fast_GET_ITEM(values, i);
if (!PyUnicode_AsUCS4(key, p, end - p, 0))
goto error;
p += PyUnicode_GET_LENGTH(key);
*p++ = '=';
if (!PyUnicode_AsUCS4(value, p, end - p, 0))
goto error;
p += PyUnicode_GET_LENGTH(value);
*p++ = '\0';
PyObject* key = PyList_GET_ITEM(keys, i);
PyObject* value = PyList_GET_ITEM(values, i);
Py_ssize_t size = PyUnicode_AsWideChar(key, p, end - p);
assert(1 <= size && size < end - p);
p += size;
*p++ = L'=';
size = PyUnicode_AsWideChar(value, p, end - p);
assert(0 <= size && size < end - p);
p += size + 1;
}

/* add trailing null byte */
*p++ = '\0';
/* add trailing null character */
*p++ = L'\0';
assert(p == end);

Py_XDECREF(keys);
Py_XDECREF(values);

res = PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, buffer, p - buffer);
PyMem_Free(buffer);
return res;

error:
PyMem_Free(buffer);
Py_XDECREF(keys);
Py_XDECREF(values);
return NULL;
return buffer;
}

static LPHANDLE
Expand Down Expand Up @@ -1053,8 +1051,7 @@ _winapi_CreateProcess_impl(PyObject *module,
BOOL result;
PROCESS_INFORMATION pi;
STARTUPINFOEXW si;
PyObject *environment = NULL;
wchar_t *wenvironment;
wchar_t *wenvironment = NULL;
wchar_t *command_line_copy = NULL;
AttributeList attribute_list = {0};

Expand All @@ -1071,20 +1068,11 @@ _winapi_CreateProcess_impl(PyObject *module,
goto cleanup;

if (env_mapping != Py_None) {
environment = getenvironment(env_mapping);
if (environment == NULL) {
goto cleanup;
}
/* contains embedded null characters */
wenvironment = PyUnicode_AsUnicode(environment);
wenvironment = getenvironment(env_mapping);
if (wenvironment == NULL) {
goto cleanup;
}
}
else {
environment = NULL;
wenvironment = NULL;
}

if (getattributelist(startup_info, "lpAttributeList", &attribute_list) < 0)
goto cleanup;
Expand Down Expand Up @@ -1131,7 +1119,7 @@ _winapi_CreateProcess_impl(PyObject *module,

cleanup:
PyMem_Free(command_line_copy);
Py_XDECREF(environment);
PyMem_Free(wenvironment);
freeattributelist(&attribute_list);

return ret;
Expand Down