Modules/grpmodule.c

Source:

cpython 3.14 @ ab2d84fe1023/Modules/grpmodule.c ↗

grp provides access to the POSIX group database (/etc/group). Available only on Unix-like systems.

Map

Lines	Symbol	Role
1-60	mkgrent	Convert a C struct group * to a Python named tuple
61-120	grp_getgrgid	Look up group by numeric GID
121-180	grp_getgrnam	Look up group by name
181-250	grp_getgrall	Return all groups as a list

Reading

mkgrent

// CPython: Modules/grpmodule.c:38 mkgrent
static PyObject *
mkgrent(PyObject *module, struct group *p)
{
    /* Returns grp.struct_group(gr_name, gr_passwd, gr_gid, gr_mem) */
    PyObject *v = PyStructSequence_New(&StructGrpType);
    PyStructSequence_SET_ITEM(v, 0, PyUnicode_DecodeFSDefault(p->gr_name));
    PyStructSequence_SET_ITEM(v, 1, PyUnicode_DecodeFSDefault(p->gr_passwd));
    PyStructSequence_SET_ITEM(v, 2, PyLong_FromLong((long)p->gr_gid));
    /* gr_mem: NULL-terminated array of member names → Python list */
    PyObject *members = PyList_New(0);
    for (char **mem = p->gr_mem; *mem; mem++)
        PyList_Append(members, PyUnicode_DecodeFSDefault(*mem));
    PyStructSequence_SET_ITEM(v, 3, members);
    return v;
}

getgrgid

// CPython: Modules/grpmodule.c:82 grp_getgrgid
static PyObject *
grp_getgrgid(PyObject *module, PyObject *args)
{
    gid_t gid;
    PyArg_ParseTuple(args, "O&:getgrgid", _Py_Uid_Converter, &gid);
    struct group *p = getgrgid(gid);
    if (p == NULL) {
        PyErr_Format(PyExc_KeyError, "getgrgid(): gid not found: %d", (int)gid);
        return NULL;
    }
    return mkgrent(module, p);
}

getgrall

// CPython: Modules/grpmodule.c:200 grp_getgrall
static PyObject *
grp_getgrall(PyObject *module, PyObject *Py_UNUSED(ignored))
{
    PyObject *d = PyList_New(0);
    struct group *p;
    setgrent();  /* rewind */
    while ((p = getgrent()) != NULL) {
        PyList_Append(d, mkgrent(module, p));
    }
    endgrent();
    return d;
}

gopy notes

grp is in module/grp/. getgrgid calls user.LookupGroupId(fmt.Sprint(gid)) from Go's os/user package. getgrnam calls user.LookupGroup(name). getgrall reads /etc/group directly (Go's os/user doesn't expose it). The named tuple is objects.StructGroup.