diff options
author | Johannes Berg <johannes@sipsolutions.net> | 2010-05-20 05:42:51 -0400 |
---|---|---|
committer | Johannes Berg <johannes@sipsolutions.net> | 2010-05-25 07:17:03 -0400 |
commit | 339321b326d241dcf6490ed910e8122486e29cd6 (patch) | |
tree | d4cc06dbc9ad286c1df9105ca253f449e91f262a | |
parent | df4d5ba4cb86f1055160559c9b7024e3dbf76a38 (diff) |
python plugin
This adds a python plugin that can in turn
load plugins written in python.
To make it work, trace-cmd needs to load
plugin modules with RTLD_GLOBAL so that
the python interpreter's symbols will be
available to python C extension modules.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
-rw-r--r-- | Documentation/README.PythonPlugin | 127 | ||||
-rw-r--r-- | Makefile | 19 | ||||
-rw-r--r-- | ctracecmd.i | 6 | ||||
-rw-r--r-- | plugin_python.c | 136 | ||||
-rw-r--r-- | trace-util.c | 2 |
5 files changed, 289 insertions, 1 deletions
diff --git a/Documentation/README.PythonPlugin b/Documentation/README.PythonPlugin new file mode 100644 index 0000000..3de0564 --- /dev/null +++ b/Documentation/README.PythonPlugin | |||
@@ -0,0 +1,127 @@ | |||
1 | PYTHON PLUGIN DOCUMENTATION | ||
2 | ============================= | ||
3 | |||
4 | With the python plugin (make python-plugin) you can now | ||
5 | write plugins in python. The API exported by the python | ||
6 | plugin itself (written in C) allows you to access most | ||
7 | information about a record from python. | ||
8 | |||
9 | To write a python plugin, put a new .py file into a new | ||
10 | ~/.trace-cmd/python/ directory. | ||
11 | |||
12 | The most basic python plugin is this: | ||
13 | |||
14 | --- %< --- | ||
15 | def register(pevent): | ||
16 | pass | ||
17 | --- >% --- | ||
18 | |||
19 | which obviously does nothing at all. | ||
20 | |||
21 | To register a callback, use the pevent.register_event_handler | ||
22 | function: | ||
23 | |||
24 | --- %< --- | ||
25 | import tracecmd | ||
26 | |||
27 | def my_event_handler(trace_seq, event): | ||
28 | pass | ||
29 | |||
30 | def register(pevent): | ||
31 | pevent.register_event_handler("subsys", "event_name", | ||
32 | my_event_handler) | ||
33 | --- >% --- | ||
34 | |||
35 | |||
36 | There are four object types that you get, described below. | ||
37 | |||
38 | tracecmd.PEvent | ||
39 | ----------------- | ||
40 | |||
41 | This is the class of the 'pevent' object above, | ||
42 | you get one of those via your register callback. | ||
43 | It has one method and one property: | ||
44 | * register_event_handler() - example above, to register | ||
45 | an event handler function | ||
46 | * file_endian - either '<' or '>' indicating | ||
47 | which endianness the file has, | ||
48 | to be used with struct.unpack() | ||
49 | |||
50 | tracecmd.TraceSeq | ||
51 | ------------------- | ||
52 | |||
53 | This is the class of the 'trace_seq' parameter to your callback | ||
54 | function. It has only one method, puts(), to put data into the | ||
55 | buffer. Formatting must be done in python. | ||
56 | |||
57 | tracecmd.Event | ||
58 | ---------------------- | ||
59 | |||
60 | This is the class of the 'event' parameter to your callback | ||
61 | function. Note that it doesn't just contain the format, but | ||
62 | also the event data. As such, you can do much with this, and | ||
63 | this is what you'll usually use. Each instance of this allows | ||
64 | access to record items via the dict protocol, and you can get | ||
65 | the items via its keys() methods. So for example, your | ||
66 | callback could be | ||
67 | |||
68 | --- %< --- | ||
69 | def my_callback(trace_seq, event): | ||
70 | for fieldname in event.keys(): | ||
71 | field = event[fieldname] | ||
72 | --- >% --- | ||
73 | |||
74 | Each field returned from the dict protocol is an instance of | ||
75 | the next (and last) class: | ||
76 | |||
77 | tracecmd.Field | ||
78 | ---------------------- | ||
79 | |||
80 | This is an instance of a field, including its data. It affords | ||
81 | numerous use cases and is what you'll be using most. | ||
82 | |||
83 | * If this is an integer field, i.e. 1, 2, 4 or 8 bytes long, | ||
84 | you can convert it to the number contained, according to | ||
85 | the file's endianness, by simply casting it to a long: | ||
86 | |||
87 | field = event['myint'] | ||
88 | value = long(field) | ||
89 | |||
90 | * You can access the field's data, as field.data, and if the | ||
91 | data is really a "__data_loc" type that will be resolved | ||
92 | automatically. (If you don't know what this means, don't | ||
93 | worry about it and just use field.data) | ||
94 | |||
95 | |||
96 | This is it. It's pretty simple. A fully-featured plugin could | ||
97 | look like this: | ||
98 | |||
99 | --- %< --- | ||
100 | def my_event_handler(trace_seq, event): | ||
101 | trace_seq.puts("myev: %u", long(event['myfield'])) | ||
102 | |||
103 | def register(pevent): | ||
104 | pevent.register_event_handler("subsys", "event_name", | ||
105 | my_event_handler) | ||
106 | --- >% --- | ||
107 | |||
108 | |||
109 | Tips and tricks | ||
110 | ----------------- | ||
111 | |||
112 | Be familiar with the struct module and use it, always | ||
113 | checking endianness and potentially using pevent.file_endian. | ||
114 | |||
115 | |||
116 | If you need access to pevent in your callbacks, simply | ||
117 | pass it in yourself: | ||
118 | |||
119 | --- %< --- | ||
120 | def my_event_handler(pevent, trace_seq, event): | ||
121 | pass | ||
122 | |||
123 | def register(pevent): | ||
124 | pevent.register_event_handler("subsys", "event_name", | ||
125 | lambda *args: my_event_handler(pevent, *args) | ||
126 | ) | ||
127 | --- >% --- | ||
@@ -439,6 +439,8 @@ clean: | |||
439 | ##### PYTHON STUFF ##### | 439 | ##### PYTHON STUFF ##### |
440 | 440 | ||
441 | PYTHON_INCLUDES = `python-config --includes` | 441 | PYTHON_INCLUDES = `python-config --includes` |
442 | PYTHON_LDFLAGS = `python-config --ldflags` \ | ||
443 | $(shell python -c "import distutils.sysconfig; print distutils.sysconfig.get_config_var('LINKFORSHARED')") | ||
442 | PYGTK_CFLAGS = `pkg-config --cflags pygtk-2.0` | 444 | PYGTK_CFLAGS = `pkg-config --cflags pygtk-2.0` |
443 | 445 | ||
444 | ctracecmd.so: $(TCMD_LIB_OBJS) ctracecmd.i | 446 | ctracecmd.so: $(TCMD_LIB_OBJS) ctracecmd.i |
@@ -457,6 +459,23 @@ python: ctracecmd.so | |||
457 | PHONY += python-gui | 459 | PHONY += python-gui |
458 | python-gui: ctracecmd.so ctracecmdgui.so | 460 | python-gui: ctracecmd.so ctracecmdgui.so |
459 | 461 | ||
462 | PHONY += python-plugin | ||
463 | python-plugin: plugin_python.so python | ||
464 | |||
465 | do_compile_python_plugin_obj = \ | ||
466 | ($(print_plugin_obj_compile) \ | ||
467 | $(CC) -c $(CFLAGS) $(PYTHON_INCLUDES) -fPIC -o $@ $<) | ||
468 | |||
469 | do_python_plugin_build = \ | ||
470 | ($(print_plugin_build) \ | ||
471 | $(CC) -shared $(PYTHON_LDFLAGS) -o $@ $<) | ||
472 | |||
473 | plugin_python.o: %.o : $(src)/%.c | ||
474 | $(Q)$(do_compile_python_plugin_obj) | ||
475 | |||
476 | plugin_python.so: %.so: %.o | ||
477 | $(Q)$(do_python_plugin_build) | ||
478 | |||
460 | endif # skip-makefile | 479 | endif # skip-makefile |
461 | 480 | ||
462 | PHONY += force | 481 | PHONY += force |
diff --git a/ctracecmd.i b/ctracecmd.i index 624fb63..a0baa3c 100644 --- a/ctracecmd.i +++ b/ctracecmd.i | |||
@@ -34,6 +34,12 @@ static int python_callback(struct trace_seq *s, | |||
34 | struct event_format *event, | 34 | struct event_format *event, |
35 | void *context); | 35 | void *context); |
36 | 36 | ||
37 | PyObject *convert_pevent(unsigned long pevent) | ||
38 | { | ||
39 | void *pev = (void *)pevent; | ||
40 | return SWIG_NewPointerObj(SWIG_as_voidptr(pev), SWIGTYPE_p_pevent, 0); | ||
41 | } | ||
42 | |||
37 | void py_pevent_register_event_handler(struct pevent *pevent, int id, | 43 | void py_pevent_register_event_handler(struct pevent *pevent, int id, |
38 | char *subsys, char *evname, | 44 | char *subsys, char *evname, |
39 | PyObject *pyfunc) | 45 | PyObject *pyfunc) |
diff --git a/plugin_python.c b/plugin_python.c new file mode 100644 index 0000000..164e774 --- /dev/null +++ b/plugin_python.c | |||
@@ -0,0 +1,136 @@ | |||
1 | #include <Python.h> | ||
2 | #ifndef _GNU_SOURCE | ||
3 | #define _GNU_SOURCE | ||
4 | #endif | ||
5 | #include <stdio.h> | ||
6 | #include <dirent.h> | ||
7 | #include <fnmatch.h> | ||
8 | #include "trace-cmd.h" | ||
9 | |||
10 | static const char pyload[] = | ||
11 | "import imp, tracecmd, ctracecmd\n" | ||
12 | "fn = r'%s'\n" | ||
13 | "file = open(fn, 'r')\n" | ||
14 | "try:\n" | ||
15 | " module = imp.load_source('%s', fn, file)\n" | ||
16 | " module.register(tracecmd.PEvent(ctracecmd.convert_pevent(pevent)))\n" | ||
17 | "finally:\n" | ||
18 | " file.close()\n"; | ||
19 | |||
20 | static void load_plugin(PyObject *globals, char *path, const char *name) | ||
21 | { | ||
22 | int len = strlen(path) + strlen(name) + 2; | ||
23 | int nlen = strlen(name) + 1; | ||
24 | char *full = malloc(len); | ||
25 | char *n = malloc(nlen); | ||
26 | char *load; | ||
27 | PyObject *res; | ||
28 | |||
29 | if (!full || !n) | ||
30 | return; | ||
31 | |||
32 | strcpy(full, path); | ||
33 | strcat(full, "/"); | ||
34 | strcat(full, name); | ||
35 | |||
36 | strcpy(n, name); | ||
37 | n[nlen - 4] = '\0'; | ||
38 | |||
39 | asprintf(&load, pyload, full, n); | ||
40 | if (!load) | ||
41 | return; | ||
42 | |||
43 | res = PyRun_String(load, Py_file_input, globals, globals); | ||
44 | if (!res) { | ||
45 | fprintf(stderr, "failed loading %s\n", full); | ||
46 | PyErr_Print(); | ||
47 | } else | ||
48 | Py_DECREF(res); | ||
49 | |||
50 | free(load); | ||
51 | } | ||
52 | |||
53 | static int load_plugins(PyObject *globals, char *path) | ||
54 | { | ||
55 | struct dirent *dent; | ||
56 | struct stat st; | ||
57 | DIR *dir; | ||
58 | int ret; | ||
59 | |||
60 | ret = stat(path, &st); | ||
61 | if (ret < 0) | ||
62 | return -1; | ||
63 | |||
64 | if (!S_ISDIR(st.st_mode)) | ||
65 | return -1; | ||
66 | |||
67 | dir = opendir(path); | ||
68 | if (!dir) | ||
69 | return -1; | ||
70 | |||
71 | while ((dent = readdir(dir))) { | ||
72 | const char *name = dent->d_name; | ||
73 | |||
74 | if (fnmatch("*.py", name, FNM_PERIOD)) | ||
75 | continue; | ||
76 | |||
77 | load_plugin(globals, path, name); | ||
78 | } | ||
79 | |||
80 | closedir(dir); | ||
81 | |||
82 | return 0; | ||
83 | } | ||
84 | |||
85 | #define LOCAL_PLUGIN_DIR ".trace-cmd/python" | ||
86 | |||
87 | int PEVENT_PLUGIN_LOADER(struct pevent *pevent) | ||
88 | { | ||
89 | char *home; | ||
90 | char *path; | ||
91 | int ret; | ||
92 | PyObject *globals, *m, *py_pevent, *str; | ||
93 | |||
94 | home = getenv("HOME"); | ||
95 | if (!home) | ||
96 | return 0; | ||
97 | |||
98 | Py_Initialize(); | ||
99 | |||
100 | m = PyImport_AddModule("__main__"); | ||
101 | globals = PyModule_GetDict(m); | ||
102 | |||
103 | str = PyString_FromString("pevent"); | ||
104 | if (!str) | ||
105 | return -ENOMEM; | ||
106 | |||
107 | py_pevent = PyLong_FromUnsignedLong((unsigned long)pevent); | ||
108 | if (!py_pevent) | ||
109 | return -ENOMEM; | ||
110 | |||
111 | if (PyDict_SetItem(globals, str, py_pevent)) | ||
112 | fprintf(stderr, "failed to insert pevent\n"); | ||
113 | |||
114 | Py_DECREF(py_pevent); | ||
115 | Py_DECREF(str); | ||
116 | |||
117 | path = malloc(strlen(home) + strlen(LOCAL_PLUGIN_DIR) + 2); | ||
118 | if (!path) | ||
119 | return -1; | ||
120 | |||
121 | strcpy(path, home); | ||
122 | strcat(path, "/"); | ||
123 | strcat(path, LOCAL_PLUGIN_DIR); | ||
124 | |||
125 | ret = load_plugins(globals, path); | ||
126 | |||
127 | free(path); | ||
128 | |||
129 | return ret; | ||
130 | } | ||
131 | |||
132 | int PEVENT_PLUGIN_UNLOADER(void) | ||
133 | { | ||
134 | Py_Finalize(); | ||
135 | return 0; | ||
136 | } | ||
diff --git a/trace-util.c b/trace-util.c index 7c0481a..4fd1d38 100644 --- a/trace-util.c +++ b/trace-util.c | |||
@@ -212,7 +212,7 @@ load_plugin(struct pevent *pevent, struct plugin_list *plugin_list, | |||
212 | strcat(plugin, "/"); | 212 | strcat(plugin, "/"); |
213 | strcat(plugin, file); | 213 | strcat(plugin, file); |
214 | 214 | ||
215 | handle = dlopen(plugin, RTLD_NOW); | 215 | handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL); |
216 | if (!handle) { | 216 | if (!handle) { |
217 | warning("cound not load plugin '%s'\n%s\n", | 217 | warning("cound not load plugin '%s'\n%s\n", |
218 | plugin, dlerror()); | 218 | plugin, dlerror()); |