| 1 | /* |
| 2 | * SPDX-License-Identifier: MIT |
| 3 | * |
| 4 | * Copyright (c) 2019 EfficiOS Inc. and Linux Foundation |
| 5 | * Copyright (c) 2019 Philippe Proulx <pproulx@efficios.com> |
| 6 | * Copyright (c) 2019 Simon Marchi <simon.marchi@efficios.com> |
| 7 | */ |
| 8 | |
| 9 | #define BT_LOG_OUTPUT_LEVEL log_level |
| 10 | #define BT_LOG_TAG "PY-COMMON" |
| 11 | #include "logging/log.h" |
| 12 | |
| 13 | #include <stdbool.h> |
| 14 | |
| 15 | #include <Python.h> |
| 16 | |
| 17 | #include "common/assert.h" |
| 18 | #include "py-common.h" |
| 19 | |
| 20 | /* |
| 21 | * Concatenate strings in list `py_str_list`, returning the result as a |
| 22 | * GString. Remove the trailing \n, if the last string ends with a \n. |
| 23 | */ |
| 24 | static |
| 25 | GString *py_str_list_to_gstring(PyObject *py_str_list, int log_level) |
| 26 | { |
| 27 | Py_ssize_t i; |
| 28 | GString *gstr; |
| 29 | |
| 30 | gstr = g_string_new(NULL); |
| 31 | if (!gstr) { |
| 32 | BT_LOGE("Failed to allocate a GString."); |
| 33 | goto end; |
| 34 | } |
| 35 | |
| 36 | for (i = 0; i < PyList_Size(py_str_list); i++) { |
| 37 | PyObject *py_str; |
| 38 | const char *str; |
| 39 | |
| 40 | py_str = PyList_GetItem(py_str_list, i); |
| 41 | BT_ASSERT(py_str); |
| 42 | BT_ASSERT(PyUnicode_CheckExact(py_str)); |
| 43 | |
| 44 | /* `str` is owned by `py_str`, not by us */ |
| 45 | str = PyUnicode_AsUTF8(py_str); |
| 46 | if (!str) { |
| 47 | if (BT_LOG_ON_ERROR) { |
| 48 | BT_LOGE_STR("PyUnicode_AsUTF8() failed:"); |
| 49 | PyErr_Print(); |
| 50 | } |
| 51 | |
| 52 | goto error; |
| 53 | } |
| 54 | |
| 55 | /* `str` has a trailing newline */ |
| 56 | g_string_append(gstr, str); |
| 57 | } |
| 58 | |
| 59 | if (gstr->len > 0) { |
| 60 | /* Remove trailing newline if any */ |
| 61 | if (gstr->str[gstr->len - 1] == '\n') { |
| 62 | g_string_truncate(gstr, gstr->len - 1); |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | goto end; |
| 67 | |
| 68 | error: |
| 69 | g_string_free(gstr, TRUE); |
| 70 | gstr = NULL; |
| 71 | |
| 72 | end: |
| 73 | return gstr; |
| 74 | } |
| 75 | |
| 76 | BT_HIDDEN |
| 77 | GString *bt_py_common_format_tb(PyObject *py_exc_tb, int log_level) |
| 78 | { |
| 79 | PyObject *traceback_module = NULL; |
| 80 | PyObject *format_tb_func = NULL; |
| 81 | PyObject *exc_str_list = NULL; |
| 82 | GString *msg_buf = NULL; |
| 83 | |
| 84 | BT_ASSERT(py_exc_tb); |
| 85 | |
| 86 | /* |
| 87 | * Import the standard `traceback` module which contains the |
| 88 | * functions to format a traceback. |
| 89 | */ |
| 90 | traceback_module = PyImport_ImportModule("traceback"); |
| 91 | if (!traceback_module) { |
| 92 | BT_LOGE_STR("Failed to import `traceback` module."); |
| 93 | goto error; |
| 94 | } |
| 95 | |
| 96 | format_tb_func = PyObject_GetAttrString(traceback_module, |
| 97 | "format_tb"); |
| 98 | if (!format_tb_func) { |
| 99 | BT_LOGE("Cannot find `format_tb` attribute in `traceback` module."); |
| 100 | goto error; |
| 101 | } |
| 102 | |
| 103 | if (!PyCallable_Check(format_tb_func)) { |
| 104 | BT_LOGE("`traceback.format_tb` attribute is not callable."); |
| 105 | goto error; |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | * If we are calling format_exception_only, `py_exc_tb` is NULL, so the |
| 110 | * effective argument list is of length 2. |
| 111 | */ |
| 112 | exc_str_list = PyObject_CallFunctionObjArgs( |
| 113 | format_tb_func, py_exc_tb, NULL); |
| 114 | if (!exc_str_list) { |
| 115 | if (BT_LOG_ON_ERROR) { |
| 116 | BT_LOGE("Failed to call `traceback.format_tb` function:"); |
| 117 | PyErr_Print(); |
| 118 | } |
| 119 | |
| 120 | goto error; |
| 121 | } |
| 122 | |
| 123 | msg_buf = py_str_list_to_gstring(exc_str_list, log_level); |
| 124 | if (!msg_buf) { |
| 125 | goto error; |
| 126 | } |
| 127 | |
| 128 | error: |
| 129 | Py_XDECREF(traceback_module); |
| 130 | Py_XDECREF(format_tb_func); |
| 131 | Py_XDECREF(exc_str_list); |
| 132 | |
| 133 | return msg_buf; |
| 134 | } |
| 135 | |
| 136 | BT_HIDDEN |
| 137 | GString *bt_py_common_format_exception(PyObject *py_exc_type, |
| 138 | PyObject *py_exc_value, PyObject *py_exc_tb, |
| 139 | int log_level, bool chain) |
| 140 | { |
| 141 | PyObject *traceback_module = NULL; |
| 142 | PyObject *format_exception_func = NULL; |
| 143 | PyObject *exc_str_list = NULL; |
| 144 | GString *msg_buf = NULL; |
| 145 | const char *format_exc_func_name; |
| 146 | |
| 147 | /* |
| 148 | * Import the standard `traceback` module which contains the |
| 149 | * functions to format an exception. |
| 150 | */ |
| 151 | traceback_module = PyImport_ImportModule("traceback"); |
| 152 | if (!traceback_module) { |
| 153 | BT_LOGE_STR("Failed to import `traceback` module."); |
| 154 | goto error; |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * `py_exc_tb` can be `NULL`, when we fail to call a Python |
| 159 | * function from native code (there is no Python stack at that |
| 160 | * point). For example, a function which takes 5 positional |
| 161 | * arguments, but 8 were given. |
| 162 | */ |
| 163 | format_exc_func_name = py_exc_tb ? "format_exception" : |
| 164 | "format_exception_only"; |
| 165 | format_exception_func = PyObject_GetAttrString(traceback_module, |
| 166 | format_exc_func_name); |
| 167 | if (!format_exception_func) { |
| 168 | BT_LOGE("Cannot find `%s` attribute in `traceback` module.", |
| 169 | format_exc_func_name); |
| 170 | goto error; |
| 171 | } |
| 172 | |
| 173 | if (!PyCallable_Check(format_exception_func)) { |
| 174 | BT_LOGE("`traceback.%s` attribute is not callable.", |
| 175 | format_exc_func_name); |
| 176 | goto error; |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * If we are calling format_exception_only, `py_exc_tb` is NULL, so the |
| 181 | * effective argument list is of length 2. |
| 182 | */ |
| 183 | exc_str_list = PyObject_CallFunctionObjArgs(format_exception_func, |
| 184 | py_exc_type, py_exc_value, py_exc_tb, Py_None /* limit */, |
| 185 | chain ? Py_True : Py_False /* chain */, NULL); |
| 186 | if (!exc_str_list) { |
| 187 | if (BT_LOG_ON_ERROR) { |
| 188 | BT_LOGE("Failed to call `traceback.%s` function:", |
| 189 | format_exc_func_name); |
| 190 | PyErr_Print(); |
| 191 | } |
| 192 | |
| 193 | goto error; |
| 194 | } |
| 195 | |
| 196 | msg_buf = py_str_list_to_gstring(exc_str_list, log_level); |
| 197 | if (!msg_buf) { |
| 198 | goto error; |
| 199 | } |
| 200 | |
| 201 | error: |
| 202 | Py_XDECREF(exc_str_list); |
| 203 | Py_XDECREF(format_exception_func); |
| 204 | Py_XDECREF(traceback_module); |
| 205 | |
| 206 | return msg_buf; |
| 207 | } |
| 208 | |
| 209 | BT_HIDDEN |
| 210 | GString *bt_py_common_format_current_exception(int log_level) |
| 211 | { |
| 212 | GString *result; |
| 213 | PyObject *py_exc_type = NULL; |
| 214 | PyObject *py_exc_value = NULL; |
| 215 | PyObject *py_exc_tb = NULL; |
| 216 | |
| 217 | BT_ASSERT(PyErr_Occurred()); |
| 218 | PyErr_Fetch(&py_exc_type, &py_exc_value, &py_exc_tb); |
| 219 | BT_ASSERT(py_exc_type); |
| 220 | |
| 221 | /* |
| 222 | * Make sure `py_exc_value` is what we expected: an instance of |
| 223 | * `py_exc_type`. |
| 224 | */ |
| 225 | PyErr_NormalizeException(&py_exc_type, &py_exc_value, &py_exc_tb); |
| 226 | |
| 227 | result = bt_py_common_format_exception(py_exc_type, py_exc_value, |
| 228 | py_exc_tb, log_level, true); |
| 229 | |
| 230 | /* |
| 231 | * We can safely call PyErr_Restore() because we always call |
| 232 | * PyErr_Fetch(), and having an error indicator is a function's |
| 233 | * precondition. |
| 234 | * |
| 235 | * PyErr_Restore() steals our references. |
| 236 | */ |
| 237 | PyErr_Restore(py_exc_type, py_exc_value, py_exc_tb); |
| 238 | |
| 239 | return result; |
| 240 | } |