| 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 | |
| 29 | #include <stdbool.h> |
| 30 | |
| 31 | #include <Python.h> |
| 32 | |
| 33 | #include "common/assert.h" |
| 34 | #include "py-common.h" |
| 35 | |
| 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 | |
| 160 | BT_HIDDEN |
| 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) |
| 164 | { |
| 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; |
| 170 | |
| 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 | /* |
| 182 | * `py_exc_tb` can be `NULL`, when we fail to call a Python |
| 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 | */ |
| 187 | format_exc_func_name = py_exc_tb ? "format_exception" : |
| 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 | |
| 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 | */ |
| 207 | exc_str_list = PyObject_CallFunctionObjArgs(format_exception_func, |
| 208 | py_exc_type, py_exc_value, py_exc_tb, Py_None /* limit */, |
| 209 | chain ? Py_True : Py_False /* chain */, NULL); |
| 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 | |
| 220 | msg_buf = py_str_list_to_gstring(exc_str_list, log_level); |
| 221 | if (!msg_buf) { |
| 222 | goto error; |
| 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 | |
| 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 | |
| 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 | */ |
| 269 | PyErr_Restore(py_exc_type, py_exc_value, py_exc_tb); |
| 270 | |
| 271 | return result; |
| 272 | } |