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gh-87804: Fix error handling and style in _pystatvfs_fromstructstatfs #115236

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Merged
merged 1 commit into from
Feb 12, 2024
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gh-87804: Fix error handling and style in _pystatvfs_fromstructstatfs #115236

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64 changes: 33 additions & 31 deletions Modules/posixmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12894,49 +12894,51 @@ os_WSTOPSIG_impl(PyObject *module, int status)

#ifdef __APPLE__
/* On macOS struct statvfs uses 32-bit integers for block counts,
* resulting in overflow when filesystems are larger tan 4TB. Therefore
* resulting in overflow when filesystems are larger than 4TB. Therefore
* os.statvfs is implemented in terms of statfs(2).
*/

static PyObject*
_pystatvfs_fromstructstatfs(PyObject *module, struct statfs st) {
PyObject *StatVFSResultType = get_posix_state(module)->StatVFSResultType;
PyObject *v = PyStructSequence_New((PyTypeObject *)StatVFSResultType);
if (v == NULL)
if (v == NULL) {
return NULL;
}

long flags = 0;
if (st.f_flags & MNT_RDONLY) {
flags |= ST_RDONLY;
}
if (st.f_flags & MNT_NOSUID) {
flags |= ST_NOSUID;
}
long flags = 0;
if (st.f_flags & MNT_RDONLY) {
flags |= ST_RDONLY;
}
if (st.f_flags & MNT_NOSUID) {
flags |= ST_NOSUID;
}

_Static_assert(sizeof(st.f_blocks) == sizeof(long long), "assuming large file");
_Static_assert(sizeof(st.f_blocks) == sizeof(long long), "assuming large file");

PyStructSequence_SET_ITEM(v, 0, PyLong_FromLong((long) st.f_iosize));
PyStructSequence_SET_ITEM(v, 1, PyLong_FromLong((long) st.f_bsize));
PyStructSequence_SET_ITEM(v, 2,
PyLong_FromLongLong((long long) st.f_blocks));
PyStructSequence_SET_ITEM(v, 3,
PyLong_FromLongLong((long long) st.f_bfree));
PyStructSequence_SET_ITEM(v, 4,
PyLong_FromLongLong((long long) st.f_bavail));
PyStructSequence_SET_ITEM(v, 5,
PyLong_FromLongLong((long long) st.f_files));
PyStructSequence_SET_ITEM(v, 6,
PyLong_FromLongLong((long long) st.f_ffree));
PyStructSequence_SET_ITEM(v, 7,
PyLong_FromLongLong((long long) st.f_ffree));
PyStructSequence_SET_ITEM(v, 8, PyLong_FromLong((long) flags));
#define SET_ITEM(v, index, item) \
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@sobolevn, the macro expansion of this will leak memory: item gets substituted as PyLong_FromLong, etc. at every occurrence, i.e.:

    do {
        if (PyLong_FromLong((long) st.f_iosize) == NULL) {
            Py_DECREF(v);
            return NULL;
        }
        PyStructSequence_SET_ITEM(v, 0, PyLong_FromLong((long) st.f_iosize));
    } while (0)

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Oh, looks like you already figured it out 😊

do { \
if (item == NULL) { \
Py_DECREF(v); \
return NULL; \
} \
PyStructSequence_SET_ITEM(v, index, item); \
} while (0) \

PyStructSequence_SET_ITEM(v, 9, PyLong_FromLong((long) NAME_MAX));
PyStructSequence_SET_ITEM(v, 10, PyLong_FromUnsignedLong(st.f_fsid.val[0]));
if (PyErr_Occurred()) {
Py_DECREF(v);
return NULL;
}
SET_ITEM(v, 0, PyLong_FromLong((long) st.f_iosize));
SET_ITEM(v, 1, PyLong_FromLong((long) st.f_bsize));
SET_ITEM(v, 2, PyLong_FromLongLong((long long) st.f_blocks));
SET_ITEM(v, 3, PyLong_FromLongLong((long long) st.f_bfree));
SET_ITEM(v, 4, PyLong_FromLongLong((long long) st.f_bavail));
SET_ITEM(v, 5, PyLong_FromLongLong((long long) st.f_files));
SET_ITEM(v, 6, PyLong_FromLongLong((long long) st.f_ffree));
SET_ITEM(v, 7, PyLong_FromLongLong((long long) st.f_ffree));
SET_ITEM(v, 8, PyLong_FromLong((long) flags));

SET_ITEM(v, 9, PyLong_FromLong((long) NAME_MAX));
SET_ITEM(v, 10, PyLong_FromUnsignedLong(st.f_fsid.val[0]));

#undef SET_ITEM

return v;
}
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