exception.c

   1 /*
   2  * This file is part of the libsigrokdecode project.
   3  *
   4  * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
  22 #include "libsigrokdecode.h"
  23 #include <stdarg.h>
  24 #include <glib.h>
  25
  26 static char *py_stringify(PyObject *py_obj)
  27 {
  28         PyObject *py_str, *py_bytes;
  29         char *str = NULL;
  30
  31         /* Note: Caller already ran PyGILState_Ensure(). */
  32
  33         if (!py_obj)
  34                 return NULL;
  35
  36         py_str = PyObject_Str(py_obj);
  37         if (!py_str || !PyUnicode_Check(py_str))
  38                 goto cleanup;
  39
  40         py_bytes = PyUnicode_AsUTF8String(py_str);
  41         if (!py_bytes)
  42                 goto cleanup;
  43
  44         str = g_strdup(PyBytes_AsString(py_bytes));
  45         Py_DECREF(py_bytes);
  46
  47 cleanup:
  48         Py_XDECREF(py_str);
  49         if (!str) {
  50                 PyErr_Clear();
  51                 srd_dbg("Failed to stringify object.");
  52         }
  53
  54         return str;
  55 }
  56
  57 static char *py_get_string_attr(PyObject *py_obj, const char *attr)
  58 {
  59         PyObject *py_str, *py_bytes;
  60         char *str = NULL;
  61
  62         /* Note: Caller already ran PyGILState_Ensure(). */
  63
  64         if (!py_obj)
  65                 return NULL;
  66
  67         py_str = PyObject_GetAttrString(py_obj, attr);
  68         if (!py_str || !PyUnicode_Check(py_str))
  69                 goto cleanup;
  70
  71         py_bytes = PyUnicode_AsUTF8String(py_str);
  72         if (!py_bytes)
  73                 goto cleanup;
  74
  75         str = g_strdup(PyBytes_AsString(py_bytes));
  76         Py_DECREF(py_bytes);
  77
  78 cleanup:
  79         Py_XDECREF(py_str);
  80         if (!str) {
  81                 PyErr_Clear();
  82                 srd_dbg("Failed to get object attribute %s.", attr);
  83         }
  84
  85         return str;
  86 }
  87
  88 /** @private */
  89 SRD_PRIV void srd_exception_catch(const char *format, ...)
  90 {
  91         int i, ret;
  92         va_list args;
  93         PyObject *py_etype, *py_evalue, *py_etraceback;
  94         PyObject *py_mod, *py_func, *py_tracefmt;
  95         char *msg, *etype_name, *evalue_str, *outstr;
  96         const char *etype_name_fallback;
  97         PyGILState_STATE gstate;
  98         GString *s;
  99
 100         py_etype = py_evalue = py_etraceback = py_mod = py_func = NULL;
 101
 102         va_start(args, format);
 103         msg = g_strdup_vprintf(format, args);
 104         va_end(args);
 105
 106         gstate = PyGILState_Ensure();
 107
 108         PyErr_Fetch(&py_etype, &py_evalue, &py_etraceback);
 109         if (!py_etype) {
 110                 /* No current exception, so just print the message. */
 111                 srd_err("%s.", msg);
 112                 goto cleanup;
 113         }
 114         PyErr_NormalizeException(&py_etype, &py_evalue, &py_etraceback);
 115
 116         etype_name = py_get_string_attr(py_etype, "__name__");
 117         evalue_str = py_stringify(py_evalue);
 118         etype_name_fallback = (etype_name) ? etype_name : "(unknown exception)";
 119
 120         if (evalue_str)
 121                 srd_err("%s: %s: %s", etype_name_fallback, msg, evalue_str);
 122         else
 123                 srd_err("%s: %s.", etype_name_fallback, msg);
 124
 125         g_free(evalue_str);
 126         g_free(etype_name);
 127
 128         /* If there is no traceback object, we are done. */
 129         if (!py_etraceback)
 130                 goto cleanup;
 131
 132         py_mod = py_import_by_name("traceback");
 133         if (!py_mod)
 134                 goto cleanup;
 135
 136         py_func = PyObject_GetAttrString(py_mod, "format_exception");
 137         if (!py_func || !PyCallable_Check(py_func))
 138                 goto cleanup;
 139
 140         /* Call into Python to format the stack trace. */
 141         py_tracefmt = PyObject_CallFunctionObjArgs(py_func,
 142                         py_etype, py_evalue, py_etraceback, NULL);
 143         if (!py_tracefmt || !PyList_Check(py_tracefmt))
 144                 goto cleanup;
 145
 146         s = g_string_sized_new(128);
 147         for (i = 0; i < PyList_Size(py_tracefmt); i++) {
 148                 ret = py_listitem_as_str(py_tracefmt, i, &outstr);
 149                 if (ret == 0) {
 150                         s = g_string_append(s, outstr);
 151                         g_free(outstr);
 152                 }
 153         }
 154         srd_err("%s", s->str);
 155         g_string_free(s, TRUE);
 156
 157         Py_DECREF(py_tracefmt);
 158
 159 cleanup:
 160         Py_XDECREF(py_func);
 161         Py_XDECREF(py_mod);
 162         Py_XDECREF(py_etraceback);
 163         Py_XDECREF(py_evalue);
 164         Py_XDECREF(py_etype);
 165
 166         /* Just in case. */
 167         PyErr_Clear();
 168
 169         PyGILState_Release(gstate);
 170
 171         g_free(msg);
 172 }