/*
* _inotify.c - Python extension interfacing to the Linux inotify subsystem
*
* Copyright 2006 Bryan O'Sullivan <bos@serpentine.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of version 2.1 of the GNU Lesser General
* Public License or any later version.
*/
#include <Python.h>
#include <alloca.h>
#include <sys/inotify.h>
#include <stdint.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <util.h>
/* Variables used in the event string representation */
static PyObject *join;
static PyObject *er_wm;
static PyObject *er_wmc;
static PyObject *er_wmn;
static PyObject *er_wmcn;
static PyObject *init(PyObject *self, PyObject *args)
{
PyObject *ret = NULL;
int fd = -1;
if (!PyArg_ParseTuple(args, ":init"))
goto bail;
Py_BEGIN_ALLOW_THREADS;
fd = inotify_init();
Py_END_ALLOW_THREADS;
if (fd == -1) {
PyErr_SetFromErrno(PyExc_OSError);
goto bail;
}
ret = PyInt_FromLong(fd);
if (ret == NULL)
goto bail;
goto done;
bail:
if (fd != -1)
close(fd);
Py_CLEAR(ret);
done:
return ret;
}
PyDoc_STRVAR(
init_doc,
"init() -> fd\n"
"\n"
"Initialise an inotify instance.\n"
"Return a file descriptor associated with a new inotify event queue.");
static PyObject *add_watch(PyObject *self, PyObject *args)
{
PyObject *ret = NULL;
uint32_t mask;
int wd = -1;
char *path;
int fd;
if (!PyArg_ParseTuple(args, "isI:add_watch", &fd, &path, &mask))
goto bail;
Py_BEGIN_ALLOW_THREADS;
wd = inotify_add_watch(fd, path, mask);
Py_END_ALLOW_THREADS;
if (wd == -1) {
PyErr_SetFromErrnoWithFilename(PyExc_OSError, path);
goto bail;
}
ret = PyInt_FromLong(wd);
if (ret == NULL)
goto bail;
goto done;
bail:
if (wd != -1)
inotify_rm_watch(fd, wd);
Py_CLEAR(ret);
done:
return ret;
}
PyDoc_STRVAR(
add_watch_doc,
"add_watch(fd, path, mask) -> wd\n"
"\n"
"Add a watch to an inotify instance, or modify an existing watch.\n"
"\n"
" fd: file descriptor returned by init()\n"
" path: path to watch\n"
" mask: mask of events to watch for\n"
"\n"
"Return a unique numeric watch descriptor for the inotify instance\n"
"mapped by the file descriptor.");
static PyObject *remove_watch(PyObject *self, PyObject *args)
{
uint32_t wd;
int fd;
int r;
if (!PyArg_ParseTuple(args, "iI:remove_watch", &fd, &wd))
return NULL;
Py_BEGIN_ALLOW_THREADS;
r = inotify_rm_watch(fd, wd);
Py_END_ALLOW_THREADS;
if (r == -1) {
PyErr_SetFromErrno(PyExc_OSError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
PyDoc_STRVAR(
remove_watch_doc,
"remove_watch(fd, wd)\n"
"\n"
" fd: file descriptor returned by init()\n"
" wd: watch descriptor returned by add_watch()\n"
"\n"
"Remove a watch associated with the watch descriptor wd from the\n"
"inotify instance associated with the file descriptor fd.\n"
"\n"
"Removing a watch causes an IN_IGNORED event to be generated for this\n"
"watch descriptor.");
#define bit_name(x) {x, #x}
static struct {
int bit;
const char *name;
PyObject *pyname;
} bit_names[] = {
bit_name(IN_ACCESS),
bit_name(IN_MODIFY),
bit_name(IN_ATTRIB),
bit_name(IN_CLOSE_WRITE),
bit_name(IN_CLOSE_NOWRITE),
bit_name(IN_OPEN),
bit_name(IN_MOVED_FROM),
bit_name(IN_MOVED_TO),
bit_name(IN_CREATE),
bit_name(IN_DELETE),
bit_name(IN_DELETE_SELF),
bit_name(IN_MOVE_SELF),
bit_name(IN_UNMOUNT),
bit_name(IN_Q_OVERFLOW),
bit_name(IN_IGNORED),
bit_name(IN_ONLYDIR),
bit_name(IN_DONT_FOLLOW),
bit_name(IN_MASK_ADD),
bit_name(IN_ISDIR),
bit_name(IN_ONESHOT),
{0}
};
static PyObject *decode_mask(int mask)
{
PyObject *ret = PyList_New(0);
int i;
if (ret == NULL)
goto bail;
for (i = 0; bit_names[i].bit; i++) {
if (mask & bit_names[i].bit) {
if (bit_names[i].pyname == NULL) {
bit_names[i].pyname = PyString_FromString(bit_names[i].name);
if (bit_names[i].pyname == NULL)
goto bail;
}
Py_INCREF(bit_names[i].pyname);
if (PyList_Append(ret, bit_names[i].pyname) == -1)
goto bail;
}
}
goto done;
bail:
Py_CLEAR(ret);
done:
return ret;
}
static PyObject *pydecode_mask(PyObject *self, PyObject *args)
{
int mask;
if (!PyArg_ParseTuple(args, "i:decode_mask", &mask))
return NULL;
return decode_mask(mask);
}
PyDoc_STRVAR(
decode_mask_doc,
"decode_mask(mask) -> list_of_strings\n"
"\n"
"Decode an inotify mask value into a list of strings that give the\n"
"name of each bit set in the mask.");
static char doc[] = "Low-level inotify interface wrappers.";
static void define_const(PyObject *dict, const char *name, uint32_t val)
{
PyObject *pyval = PyInt_FromLong(val);
PyObject *pyname = PyString_FromString(name);
if (!pyname || !pyval)
goto bail;
PyDict_SetItem(dict, pyname, pyval);
bail:
Py_XDECREF(pyname);
Py_XDECREF(pyval);
}
static void define_consts(PyObject *dict)
{
define_const(dict, "IN_ACCESS", IN_ACCESS);
define_const(dict, "IN_MODIFY", IN_MODIFY);
define_const(dict, "IN_ATTRIB", IN_ATTRIB);
define_const(dict, "IN_CLOSE_WRITE", IN_CLOSE_WRITE);
define_const(dict, "IN_CLOSE_NOWRITE", IN_CLOSE_NOWRITE);
define_const(dict, "IN_OPEN", IN_OPEN);
define_const(dict, "IN_MOVED_FROM", IN_MOVED_FROM);
define_const(dict, "IN_MOVED_TO", IN_MOVED_TO);
define_const(dict, "IN_CLOSE", IN_CLOSE);
define_const(dict, "IN_MOVE", IN_MOVE);
define_const(dict, "IN_CREATE", IN_CREATE);
define_const(dict, "IN_DELETE", IN_DELETE);
define_const(dict, "IN_DELETE_SELF", IN_DELETE_SELF);
define_const(dict, "IN_MOVE_SELF", IN_MOVE_SELF);
define_const(dict, "IN_UNMOUNT", IN_UNMOUNT);
define_const(dict, "IN_Q_OVERFLOW", IN_Q_OVERFLOW);
define_const(dict, "IN_IGNORED", IN_IGNORED);
define_const(dict, "IN_ONLYDIR", IN_ONLYDIR);
define_const(dict, "IN_DONT_FOLLOW", IN_DONT_FOLLOW);
define_const(dict, "IN_MASK_ADD", IN_MASK_ADD);
define_const(dict, "IN_ISDIR", IN_ISDIR);
define_const(dict, "IN_ONESHOT", IN_ONESHOT);
define_const(dict, "IN_ALL_EVENTS", IN_ALL_EVENTS);
}
struct event {
PyObject_HEAD
PyObject *wd;
PyObject *mask;
PyObject *cookie;
PyObject *name;
};
static PyObject *event_wd(PyObject *self, void *x)
{
struct event *evt = (struct event *)self;
Py_INCREF(evt->wd);
return evt->wd;
}
static PyObject *event_mask(PyObject *self, void *x)
{
struct event *evt = (struct event *)self;
Py_INCREF(evt->mask);
return evt->mask;
}
static PyObject *event_cookie(PyObject *self, void *x)
{
struct event *evt = (struct event *)self;
Py_INCREF(evt->cookie);
return evt->cookie;
}
static PyObject *event_name(PyObject *self, void *x)
{
struct event *evt = (struct event *)self;
Py_INCREF(evt->name);
return evt->name;
}
static struct PyGetSetDef event_getsets[] = {
{"wd", event_wd, NULL,
"watch descriptor"},
{"mask", event_mask, NULL,
"event mask"},
{"cookie", event_cookie, NULL,
"rename cookie, if rename-related event"},
{"name", event_name, NULL,
"file name"},
{NULL}
};
PyDoc_STRVAR(
event_doc,
"event: Structure describing an inotify event.");
static PyObject *event_new(PyTypeObject *t, PyObject *a, PyObject *k)
{
return (*t->tp_alloc)(t, 0);
}
static void event_dealloc(struct event *evt)
{
Py_XDECREF(evt->wd);
Py_XDECREF(evt->mask);
Py_XDECREF(evt->cookie);
Py_XDECREF(evt->name);
Py_TYPE(evt)->tp_free(evt);
}
static PyObject *event_repr(struct event *evt)
{
int cookie = evt->cookie == Py_None ? -1 : PyInt_AsLong(evt->cookie);
PyObject *ret = NULL, *pymasks = NULL, *pymask = NULL;
PyObject *tuple = NULL, *formatstr = NULL;
pymasks = decode_mask(PyInt_AsLong(evt->mask));
if (pymasks == NULL)
goto bail;
pymask = _PyString_Join(join, pymasks);
if (pymask == NULL)
goto bail;
if (evt->name != Py_None) {
if (cookie == -1) {
formatstr = er_wmn;
tuple = PyTuple_Pack(3, evt->wd, pymask, evt->name);
}
else {
formatstr = er_wmcn;
tuple = PyTuple_Pack(4, evt->wd, pymask,
evt->cookie, evt->name);
}
} else {
if (cookie == -1) {
formatstr = er_wm;
tuple = PyTuple_Pack(2, evt->wd, pymask);
}
else {
formatstr = er_wmc;
tuple = PyTuple_Pack(3, evt->wd, pymask, evt->cookie);
}
}
if (tuple == NULL)
goto bail;
ret = PyNumber_Remainder(formatstr, tuple);
if (ret == NULL)
goto bail;
goto done;
bail:
Py_CLEAR(ret);
done:
Py_XDECREF(pymask);
Py_XDECREF(pymasks);
Py_XDECREF(tuple);
return ret;
}
static PyTypeObject event_type = {
PyVarObject_HEAD_INIT(NULL, 0)
"_inotify.event", /*tp_name*/
sizeof(struct event), /*tp_basicsize*/
0, /*tp_itemsize*/
(destructor)event_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
(reprfunc)event_repr, /*tp_repr*/
0, /*tp_as_number*/
0, /*tp_as_sequence*/
0, /*tp_as_mapping*/
0, /*tp_hash */
0, /*tp_call*/
0, /*tp_str*/
0, /*tp_getattro*/
0, /*tp_setattro*/
0, /*tp_as_buffer*/
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
event_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
0, /* tp_members */
event_getsets, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
event_new, /* tp_new */
};
PyObject *read_events(PyObject *self, PyObject *args)
{
PyObject *ctor_args = NULL;
PyObject *pybufsize = NULL;
PyObject *ret = NULL;
int bufsize = 65536;
char *buf = NULL;
int nread, pos;
int fd;
if (!PyArg_ParseTuple(args, "i|O:read", &fd, &pybufsize))
goto bail;
if (pybufsize && pybufsize != Py_None)
bufsize = PyInt_AsLong(pybufsize);
ret = PyList_New(0);
if (ret == NULL)
goto bail;
if (bufsize <= 0) {
int r;
Py_BEGIN_ALLOW_THREADS;
r = ioctl(fd, FIONREAD, &bufsize);
Py_END_ALLOW_THREADS;
if (r == -1) {
PyErr_SetFromErrno(PyExc_OSError);
goto bail;
}
if (bufsize == 0)
goto done;
}
else {
static long name_max;
static long name_fd = -1;
long min;
if (name_fd != fd) {
name_fd = fd;
Py_BEGIN_ALLOW_THREADS;
name_max = fpathconf(fd, _PC_NAME_MAX);
Py_END_ALLOW_THREADS;
}
min = sizeof(struct inotify_event) + name_max + 1;
if (bufsize < min) {
PyErr_Format(PyExc_ValueError,
"bufsize must be at least %d", (int)min);
goto bail;
}
}
buf = alloca(bufsize);
Py_BEGIN_ALLOW_THREADS;
nread = read(fd, buf, bufsize);
Py_END_ALLOW_THREADS;
if (nread == -1) {
PyErr_SetFromErrno(PyExc_OSError);
goto bail;
}
ctor_args = PyTuple_New(0);
if (ctor_args == NULL)
goto bail;
pos = 0;
while (pos < nread) {
struct inotify_event *in = (struct inotify_event *)(buf + pos);
struct event *evt;
PyObject *obj;
obj = PyObject_CallObject((PyObject *)&event_type, ctor_args);
if (obj == NULL)
goto bail;
evt = (struct event *)obj;
evt->wd = PyInt_FromLong(in->wd);
evt->mask = PyInt_FromLong(in->mask);
if (in->mask & IN_MOVE)
evt->cookie = PyInt_FromLong(in->cookie);
else {
Py_INCREF(Py_None);
evt->cookie = Py_None;
}
if (in->len)
evt->name = PyString_FromString(in->name);
else {
Py_INCREF(Py_None);
evt->name = Py_None;
}
if (!evt->wd || !evt->mask || !evt->cookie || !evt->name)
goto mybail;
if (PyList_Append(ret, obj) == -1)
goto mybail;
pos += sizeof(struct inotify_event) + in->len;
continue;
mybail:
Py_CLEAR(evt->wd);
Py_CLEAR(evt->mask);
Py_CLEAR(evt->cookie);
Py_CLEAR(evt->name);
Py_DECREF(obj);
goto bail;
}
goto done;
bail:
Py_CLEAR(ret);
done:
Py_XDECREF(ctor_args);
return ret;
}
static int init_globals(void)
{
join = PyString_FromString("|");
er_wm = PyString_FromString("event(wd=%d, mask=%s)");
er_wmn = PyString_FromString("event(wd=%d, mask=%s, name=%s)");
er_wmc = PyString_FromString("event(wd=%d, mask=%s, cookie=0x%x)");
er_wmcn = PyString_FromString("event(wd=%d, mask=%s, cookie=0x%x, name=%s)");
return join && er_wm && er_wmn && er_wmc && er_wmcn;
}
PyDoc_STRVAR(
read_doc,
"read(fd, bufsize[=65536]) -> list_of_events\n"
"\n"
"\nRead inotify events from a file descriptor.\n"
"\n"
" fd: file descriptor returned by init()\n"
" bufsize: size of buffer to read into, in bytes\n"
"\n"
"Return a list of event objects.\n"
"\n"
"If bufsize is > 0, block until events are available to be read.\n"
"Otherwise, immediately return all events that can be read without\n"
"blocking.");
static PyMethodDef methods[] = {
{"init", init, METH_VARARGS, init_doc},
{"add_watch", add_watch, METH_VARARGS, add_watch_doc},
{"remove_watch", remove_watch, METH_VARARGS, remove_watch_doc},
{"read", read_events, METH_VARARGS, read_doc},
{"decode_mask", pydecode_mask, METH_VARARGS, decode_mask_doc},
{NULL},
};
#ifdef IS_PY3K
static struct PyModuleDef _inotify_module = {
PyModuleDef_HEAD_INIT,
"_inotify",
doc,
-1,
methods
};
PyMODINIT_FUNC PyInit__inotify(void)
{
PyObject *mod, *dict;
mod = PyModule_Create(&_inotify_module);
if (mod == NULL)
return NULL;
if (!init_globals())
return;
dict = PyModule_GetDict(mod);
if (dict)
define_consts(dict);
return mod;
}
#else
void init_inotify(void)
{
PyObject *mod, *dict;
if (PyType_Ready(&event_type) == -1)
return;
if (!init_globals())
return;
mod = Py_InitModule3("_inotify", methods, doc);
dict = PyModule_GetDict(mod);
if (dict)
define_consts(dict);
}
#endif