[babeltrace.git] / src / py-common / py-common.c

/*
 * Copyright (c) 2019 EfficiOS Inc. and Linux Foundation
 * Copyright (c) 2019 Philippe Proulx <pproulx@efficios.com>
 * Copyright (c) 2019 Simon Marchi <simon.marchi@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#define BT_LOG_OUTPUT_LEVEL log_level
#define BT_LOG_TAG "PY-COMMON"
#include "logging/log.h"

#include <stdbool.h>

#include <Python.h>

#include "common/assert.h"
#include "py-common.h"

/*
 * Concatenate strings in list `py_str_list`, returning the result as a
 * GString.  Remove the trailing \n, if the last string ends with a \n.
 */
static
GString *py_str_list_to_gstring(PyObject *py_str_list, int log_level)
{
	Py_ssize_t i;
	GString *gstr;

	gstr = g_string_new(NULL);
	if (!gstr) {
		BT_LOGE("Failed to allocate a GString.");
		goto end;
	}

	for (i = 0; i < PyList_Size(py_str_list); i++) {
		PyObject *py_str;
		const char *str;

		py_str = PyList_GetItem(py_str_list, i);
		BT_ASSERT(py_str);
		BT_ASSERT(PyUnicode_CheckExact(py_str));

		/* `str` is owned by `py_str`, not by us */
		str = PyUnicode_AsUTF8(py_str);
		if (!str) {
			if (BT_LOG_ON_ERROR) {
				BT_LOGE_STR("PyUnicode_AsUTF8() failed:");
				PyErr_Print();
			}

			goto error;
		}

		/* `str` has a trailing newline */
		g_string_append(gstr, str);
	}

	if (gstr->len > 0) {
		/* Remove trailing newline if any */
		if (gstr->str[gstr->len - 1] == '\n') {
			g_string_truncate(gstr, gstr->len - 1);
		}
	}

	goto end;

error:
	g_string_free(gstr, TRUE);
	gstr = NULL;

end:
	return gstr;
}

BT_HIDDEN
GString *bt_py_common_format_tb(PyObject *py_exc_tb, int log_level)
{
	PyObject *traceback_module = NULL;
	PyObject *format_tb_func = NULL;
	PyObject *exc_str_list = NULL;
	GString *msg_buf = NULL;

	BT_ASSERT(py_exc_tb);

	/*
	 * Import the standard `traceback` module which contains the
	 * functions to format a traceback.
	 */
	traceback_module = PyImport_ImportModule("traceback");
	if (!traceback_module) {
		BT_LOGE_STR("Failed to import `traceback` module.");
		goto error;
	}

	format_tb_func = PyObject_GetAttrString(traceback_module,
		"format_tb");
	if (!format_tb_func) {
		BT_LOGE("Cannot find `format_tb` attribute in `traceback` module.");
		goto error;
	}

	if (!PyCallable_Check(format_tb_func)) {
		BT_LOGE("`traceback.format_tb` attribute is not callable.");
		goto error;
	}

	/*
	 * If we are calling format_exception_only, `py_exc_tb` is NULL, so the
	 * effective argument list is of length 2.
	 */
	exc_str_list = PyObject_CallFunctionObjArgs(
		format_tb_func, py_exc_tb, NULL);
	if (!exc_str_list) {
		if (BT_LOG_ON_ERROR) {
			BT_LOGE("Failed to call `traceback.format_tb` function:");
			PyErr_Print();
		}

		goto error;
	}

	msg_buf = py_str_list_to_gstring(exc_str_list, log_level);
	if (!msg_buf) {
		goto error;
	}

	goto end;

error:
	if (msg_buf) {
		g_string_free(msg_buf, TRUE);
		msg_buf = NULL;
	}

end:
	Py_XDECREF(traceback_module);
	Py_XDECREF(format_tb_func);
	Py_XDECREF(exc_str_list);

	return msg_buf;
}

BT_HIDDEN
GString *bt_py_common_format_exception(PyObject *py_exc_type,
		PyObject *py_exc_value, PyObject *py_exc_tb,
		int log_level, bool chain)
{
	PyObject *traceback_module = NULL;
	PyObject *format_exception_func = NULL;
	PyObject *exc_str_list = NULL;
	GString *msg_buf = NULL;
	const char *format_exc_func_name;

	/*
	 * Import the standard `traceback` module which contains the
	 * functions to format an exception.
	 */
	traceback_module = PyImport_ImportModule("traceback");
	if (!traceback_module) {
		BT_LOGE_STR("Failed to import `traceback` module.");
		goto error;
	}

	/*
	 * `py_exc_tb` can be `NULL`, when we fail to call a Python
	 * function from native code (there is no Python stack at that
	 * point). For example, a function which takes 5 positional
	 * arguments, but 8 were given.
	 */
	format_exc_func_name = py_exc_tb ? "format_exception" :
		"format_exception_only";
	format_exception_func = PyObject_GetAttrString(traceback_module,
		format_exc_func_name);
	if (!format_exception_func) {
		BT_LOGE("Cannot find `%s` attribute in `traceback` module.",
			format_exc_func_name);
		goto error;
	}

	if (!PyCallable_Check(format_exception_func)) {
		BT_LOGE("`traceback.%s` attribute is not callable.",
			format_exc_func_name);
		goto error;
	}

	/*
	 * If we are calling format_exception_only, `py_exc_tb` is NULL, so the
	 * effective argument list is of length 2.
	 */
	exc_str_list = PyObject_CallFunctionObjArgs(format_exception_func,
		py_exc_type, py_exc_value, py_exc_tb, Py_None /* limit */,
		chain ? Py_True : Py_False /* chain */, NULL);
	if (!exc_str_list) {
		if (BT_LOG_ON_ERROR) {
			BT_LOGE("Failed to call `traceback.%s` function:",
				format_exc_func_name);
			PyErr_Print();
		}

		goto error;
	}

	msg_buf = py_str_list_to_gstring(exc_str_list, log_level);
	if (!msg_buf) {
		goto error;
	}

	goto end;

error:
	if (msg_buf) {
		g_string_free(msg_buf, TRUE);
		msg_buf = NULL;
	}

end:
	Py_XDECREF(exc_str_list);
	Py_XDECREF(format_exception_func);
	Py_XDECREF(traceback_module);

	return msg_buf;
}

BT_HIDDEN
GString *bt_py_common_format_current_exception(int log_level)
{
	GString *result;
	PyObject *py_exc_type = NULL;
	PyObject *py_exc_value = NULL;
	PyObject *py_exc_tb = NULL;

	BT_ASSERT(PyErr_Occurred());
	PyErr_Fetch(&py_exc_type, &py_exc_value, &py_exc_tb);
	BT_ASSERT(py_exc_type);

	/*
	 * Make sure `py_exc_value` is what we expected: an instance of
	 * `py_exc_type`.
	 */
	PyErr_NormalizeException(&py_exc_type, &py_exc_value, &py_exc_tb);

	result = bt_py_common_format_exception(py_exc_type, py_exc_value,
		py_exc_tb, log_level, true);

	/*
	 * We can safely call PyErr_Restore() because we always call
	 * PyErr_Fetch(), and having an error indicator is a function's
	 * precondition.
	 *
	 * PyErr_Restore() steals our references.
	 */
	PyErr_Restore(py_exc_type, py_exc_value, py_exc_tb);

	return result;
}
Commit	Line	Data
2d7aa9b6 PP	1	/*
	2	* Copyright (c) 2019 EfficiOS Inc. and Linux Foundation
	3	* Copyright (c) 2019 Philippe Proulx <pproulx@efficios.com>
	4	* Copyright (c) 2019 Simon Marchi <simon.marchi@efficios.com>
	5	*
	6	* Permission is hereby granted, free of charge, to any person obtaining a copy
	7	* of this software and associated documentation files (the "Software"), to deal
	8	* in the Software without restriction, including without limitation the rights
	9	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	10	* copies of the Software, and to permit persons to whom the Software is
	11	* furnished to do so, subject to the following conditions:
	12	*
	13	* The above copyright notice and this permission notice shall be included in
	14	* all copies or substantial portions of the Software.
	15	*
	16	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	17	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	18	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	19	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	20	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	21	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	22	* SOFTWARE.
	23	*/
	24
	25	#define BT_LOG_OUTPUT_LEVEL log_level
	26	#define BT_LOG_TAG "PY-COMMON"
	27	#include "logging/log.h"
	28
969c1d8a FD	29	#include <stdbool.h>
969c1d8a FD	30
2d7aa9b6 PP	31	#include <Python.h>
	32
	33	#include "common/assert.h"
	34	#include "py-common.h"
	35
b53cd768 SM	36	/*
	37	* Concatenate strings in list `py_str_list`, returning the result as a
	38	* GString. Remove the trailing \n, if the last string ends with a \n.
	39	*/
	40	static
	41	GString py_str_list_to_gstring(PyObject py_str_list, int log_level)
	42	{
	43	Py_ssize_t i;
	44	GString *gstr;
	45
	46	gstr = g_string_new(NULL);
	47	if (!gstr) {
	48	BT_LOGE("Failed to allocate a GString.");
	49	goto end;
	50	}
	51
	52	for (i = 0; i < PyList_Size(py_str_list); i++) {
	53	PyObject *py_str;
	54	const char *str;
	55
	56	py_str = PyList_GetItem(py_str_list, i);
	57	BT_ASSERT(py_str);
	58	BT_ASSERT(PyUnicode_CheckExact(py_str));
	59
	60	/* `str` is owned by `py_str`, not by us */
	61	str = PyUnicode_AsUTF8(py_str);
	62	if (!str) {
	63	if (BT_LOG_ON_ERROR) {
	64	BT_LOGE_STR("PyUnicode_AsUTF8() failed:");
	65	PyErr_Print();
	66	}
	67
	68	goto error;
	69	}
	70
	71	/* `str` has a trailing newline */
	72	g_string_append(gstr, str);
	73	}
	74
	75	if (gstr->len > 0) {
	76	/* Remove trailing newline if any */
	77	if (gstr->str[gstr->len - 1] == '\n') {
	78	g_string_truncate(gstr, gstr->len - 1);
	79	}
	80	}
	81
	82	goto end;
	83
	84	error:
	85	g_string_free(gstr, TRUE);
	86	gstr = NULL;
	87
	88	end:
	89	return gstr;
	90	}
	91
	92	BT_HIDDEN
	93	GString bt_py_common_format_tb(PyObject py_exc_tb, int log_level)
	94	{
	95	PyObject *traceback_module = NULL;
	96	PyObject *format_tb_func = NULL;
	97	PyObject *exc_str_list = NULL;
	98	GString *msg_buf = NULL;
	99
100	BT_ASSERT(py_exc_tb);
101
102	/*
103	* Import the standard `traceback` module which contains the
104	* functions to format a traceback.
105	*/
106	traceback_module = PyImport_ImportModule("traceback");
107	if (!traceback_module) {
108	BT_LOGE_STR("Failed to import `traceback` module.");
109	goto error;
110	}
111
112	format_tb_func = PyObject_GetAttrString(traceback_module,
113	"format_tb");
114	if (!format_tb_func) {
115	BT_LOGE("Cannot find `format_tb` attribute in `traceback` module.");
116	goto error;
117	}
118
119	if (!PyCallable_Check(format_tb_func)) {
120	BT_LOGE("`traceback.format_tb` attribute is not callable.");
121	goto error;
122	}
123
124	/*
125	* If we are calling format_exception_only, `py_exc_tb` is NULL, so the
126	* effective argument list is of length 2.
127	*/
128	exc_str_list = PyObject_CallFunctionObjArgs(
129	format_tb_func, py_exc_tb, NULL);
130	if (!exc_str_list) {
131	if (BT_LOG_ON_ERROR) {
132	BT_LOGE("Failed to call `traceback.format_tb` function:");
133	PyErr_Print();
134	}
135
136	goto error;
137	}
138
139	msg_buf = py_str_list_to_gstring(exc_str_list, log_level);
140	if (!msg_buf) {
141	goto error;
142	}
143
144	goto end;
145
146	error:
147	if (msg_buf) {
148	g_string_free(msg_buf, TRUE);
149	msg_buf = NULL;
150	}
151
152	end:
153	Py_XDECREF(traceback_module);
154	Py_XDECREF(format_tb_func);
155	Py_XDECREF(exc_str_list);
156
157	return msg_buf;
158	}
159
2d7aa9b6	160	BT_HIDDEN
f33c35fb SM	161	GString bt_py_common_format_exception(PyObject py_exc_type,
	162	PyObject py_exc_value, PyObject py_exc_tb,
	163	int log_level, bool chain)
2d7aa9b6	164	{
2d7aa9b6 PP	165	PyObject *traceback_module = NULL;
	166	PyObject *format_exception_func = NULL;
	167	PyObject *exc_str_list = NULL;
	168	GString *msg_buf = NULL;
	169	const char *format_exc_func_name;
2d7aa9b6	170
2d7aa9b6 PP	171	/*
	172	* Import the standard `traceback` module which contains the
	173	* functions to format an exception.
	174	*/
	175	traceback_module = PyImport_ImportModule("traceback");
	176	if (!traceback_module) {
	177	BT_LOGE_STR("Failed to import `traceback` module.");
	178	goto error;
	179	}
	180
	181	/*
f33c35fb	182	* `py_exc_tb` can be `NULL`, when we fail to call a Python
2d7aa9b6 PP	183	* function from native code (there is no Python stack at that
	184	* point). For example, a function which takes 5 positional
	185	* arguments, but 8 were given.
	186	*/
f33c35fb	187	format_exc_func_name = py_exc_tb ? "format_exception" :
2d7aa9b6 PP	188	"format_exception_only";
	189	format_exception_func = PyObject_GetAttrString(traceback_module,
	190	format_exc_func_name);
	191	if (!format_exception_func) {
	192	BT_LOGE("Cannot find `%s` attribute in `traceback` module.",
	193	format_exc_func_name);
	194	goto error;
	195	}
	196
	197	if (!PyCallable_Check(format_exception_func)) {
	198	BT_LOGE("`traceback.%s` attribute is not callable.",
	199	format_exc_func_name);
	200	goto error;
	201	}
	202
f33c35fb SM	203	/*
	204	* If we are calling format_exception_only, `py_exc_tb` is NULL, so the
	205	* effective argument list is of length 2.
	206	*/
2d7aa9b6	207	exc_str_list = PyObject_CallFunctionObjArgs(format_exception_func,
f33c35fb SM	208	py_exc_type, py_exc_value, py_exc_tb, Py_None /* limit */,
f33c35fb SM	209	chain ? Py_True : Py_False /* chain */, NULL);
2d7aa9b6 PP	210	if (!exc_str_list) {
	211	if (BT_LOG_ON_ERROR) {
	212	BT_LOGE("Failed to call `traceback.%s` function:",
	213	format_exc_func_name);
	214	PyErr_Print();
	215	}
	216
	217	goto error;
	218	}
	219
b53cd768 SM	220	msg_buf = py_str_list_to_gstring(exc_str_list, log_level);
	221	if (!msg_buf) {
	222	goto error;
2d7aa9b6 PP	223	}
	224
	225	goto end;
	226
	227	error:
	228	if (msg_buf) {
	229	g_string_free(msg_buf, TRUE);
	230	msg_buf = NULL;
	231	}
	232
	233	end:
	234	Py_XDECREF(exc_str_list);
	235	Py_XDECREF(format_exception_func);
	236	Py_XDECREF(traceback_module);
	237
f33c35fb SM	238	return msg_buf;
	239	}
	240
	241	BT_HIDDEN
	242	GString *bt_py_common_format_current_exception(int log_level)
	243	{
	244	GString *result;
	245	PyObject *py_exc_type = NULL;
	246	PyObject *py_exc_value = NULL;
	247	PyObject *py_exc_tb = NULL;
	248
	249	BT_ASSERT(PyErr_Occurred());
	250	PyErr_Fetch(&py_exc_type, &py_exc_value, &py_exc_tb);
	251	BT_ASSERT(py_exc_type);
	252
	253	/*
	254	* Make sure `py_exc_value` is what we expected: an instance of
	255	* `py_exc_type`.
	256	*/
	257	PyErr_NormalizeException(&py_exc_type, &py_exc_value, &py_exc_tb);
	258
	259	result = bt_py_common_format_exception(py_exc_type, py_exc_value,
	260	py_exc_tb, log_level, true);
	261
2d7aa9b6 PP	262	/*
	263	* We can safely call PyErr_Restore() because we always call
	264	* PyErr_Fetch(), and having an error indicator is a function's
	265	* precondition.
	266	*
	267	* PyErr_Restore() steals our references.
	268	*/
f33c35fb	269	PyErr_Restore(py_exc_type, py_exc_value, py_exc_tb);
2d7aa9b6	270
f33c35fb	271	return result;
2d7aa9b6	272	}