Python/traceback.c

   1
   2 /* Traceback implementation */
   3
   4 #include "Python.h"
   5
   6 #include "compile.h"
   7 #include "frameobject.h"
   8 #include "structmember.h"
   9 #include "osdefs.h"
  10
  11 typedef struct _tracebackobject {
  12         PyObject_HEAD
  13         struct _tracebackobject *tb_next;
  14         PyFrameObject *tb_frame;
  15         int tb_lasti;
  16         int tb_lineno;
  17 } tracebackobject;
  18
  19 #define OFF(x) offsetof(tracebackobject, x)
  20
  21 static struct memberlist tb_memberlist[] = {
  22         {"tb_next",     T_OBJECT,       OFF(tb_next)},
  23         {"tb_frame",    T_OBJECT,       OFF(tb_frame)},
  24         {"tb_lasti",    T_INT,          OFF(tb_lasti)},
  25         {"tb_lineno",   T_INT,          OFF(tb_lineno)},
  26         {NULL}  /* Sentinel */
  27 };
  28
  29 static PyObject *
  30 tb_getattr(tracebackobject *tb, char *name)
  31 {
  32         return PyMember_Get((char *)tb, tb_memberlist, name);
  33 }
  34
  35 static void
  36 tb_dealloc(tracebackobject *tb)
  37 {
  38         PyObject_GC_UnTrack(tb);
  39         Py_TRASHCAN_SAFE_BEGIN(tb)
  40         Py_XDECREF(tb->tb_next);
  41         Py_XDECREF(tb->tb_frame);
  42         PyObject_GC_Del(tb);
  43         Py_TRASHCAN_SAFE_END(tb)
  44 }
  45
  46 static int
  47 tb_traverse(tracebackobject *tb, visitproc visit, void *arg)
  48 {
  49         int err = 0;
  50         if (tb->tb_next) {
  51                 err = visit((PyObject *)tb->tb_next, arg);
  52                 if (err)
  53                         return err;
  54         }
  55         if (tb->tb_frame)
  56                 err = visit((PyObject *)tb->tb_frame, arg);
  57         return err;
  58 }
  59
  60 static void
  61 tb_clear(tracebackobject *tb)
  62 {
  63         Py_XDECREF(tb->tb_next);
  64         Py_XDECREF(tb->tb_frame);
  65         tb->tb_next = NULL;
  66         tb->tb_frame = NULL;
  67 }
  68
  69 PyTypeObject PyTraceBack_Type = {
  70         PyObject_HEAD_INIT(&PyType_Type)
  71         0,
  72         "traceback",
  73         sizeof(tracebackobject),
  74         0,
  75         (destructor)tb_dealloc, /*tp_dealloc*/
  76         0,              /*tp_print*/
  77         (getattrfunc)tb_getattr, /*tp_getattr*/
  78         0,              /*tp_setattr*/
  79         0,              /*tp_compare*/
  80         0,              /*tp_repr*/
  81         0,              /*tp_as_number*/
  82         0,              /*tp_as_sequence*/
  83         0,              /*tp_as_mapping*/
  84         0,              /* tp_hash */
  85         0,              /* tp_call */
  86         0,              /* tp_str */
  87         0,              /* tp_getattro */
  88         0,              /* tp_setattro */
  89         0,                                      /* tp_as_buffer */
  90         Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
  91         0,                                      /* tp_doc */
  92         (traverseproc)tb_traverse,              /* tp_traverse */
  93         (inquiry)tb_clear,                      /* tp_clear */
  94         0,                                      /* tp_richcompare */
  95         0,                                      /* tp_weaklistoffset */
  96         0,                                      /* tp_iter */
  97         0,                                      /* tp_iternext */
  98         0,                                      /* tp_methods */
  99         0,                      /* tp_members */
 100         0,                      /* tp_getset */
 101         0,                                      /* tp_base */
 102         0,                                      /* tp_dict */
 103 };
 104
 105 static tracebackobject *
 106 newtracebackobject(tracebackobject *next, PyFrameObject *frame)
 107 {
 108         tracebackobject *tb;
 109         if ((next != NULL && !PyTraceBack_Check(next)) ||
 110                         frame == NULL || !PyFrame_Check(frame)) {
 111                 PyErr_BadInternalCall();
 112                 return NULL;
 113         }
 114         tb = PyObject_GC_New(tracebackobject, &PyTraceBack_Type);
 115         if (tb != NULL) {
 116                 Py_XINCREF(next);
 117                 tb->tb_next = next;
 118                 Py_XINCREF(frame);
 119                 tb->tb_frame = frame;
 120                 tb->tb_lasti = frame->f_lasti;
 121                 tb->tb_lineno = PyCode_Addr2Line(frame->f_code,
 122                                                  frame->f_lasti);
 123                 PyObject_GC_Track(tb);
 124         }
 125         return tb;
 126 }
 127
 128 int
 129 PyTraceBack_Here(PyFrameObject *frame)
 130 {
 131         PyThreadState *tstate = frame->f_tstate;
 132         tracebackobject *oldtb = (tracebackobject *) tstate->curexc_traceback;
 133         tracebackobject *tb = newtracebackobject(oldtb, frame);
 134         if (tb == NULL)
 135                 return -1;
 136         tstate->curexc_traceback = (PyObject *)tb;
 137         Py_XDECREF(oldtb);
 138         return 0;
 139 }
 140
 141 static int
 142 tb_displayline(PyObject *f, char *filename, int lineno, char *name)
 143 {
 144         int err = 0;
 145         FILE *xfp;
 146         char linebuf[2000];
 147         int i;
 148         if (filename == NULL || name == NULL)
 149                 return -1;
 150 #ifdef MPW
 151         /* This is needed by MPW's File and Line commands */
 152 #define FMT "  File \"%.500s\"; line %d # in %.500s\n"
 153 #else
 154         /* This is needed by Emacs' compile command */
 155 #define FMT "  File \"%.500s\", line %d, in %.500s\n"
 156 #endif
 157         xfp = fopen(filename, "r" PY_STDIOTEXTMODE);
 158         if (xfp == NULL) {
 159                 /* Search tail of filename in sys.path before giving up */
 160                 PyObject *path;
 161                 char *tail = strrchr(filename, SEP);
 162                 if (tail == NULL)
 163                         tail = filename;
 164                 else
 165                         tail++;
 166                 path = PySys_GetObject("path");
 167                 if (path != NULL && PyList_Check(path)) {
 168                         int npath = PyList_Size(path);
 169                         size_t taillen = strlen(tail);
 170                         char namebuf[MAXPATHLEN+1];
 171                         for (i = 0; i < npath; i++) {
 172                                 PyObject *v = PyList_GetItem(path, i);
 173                                 if (v == NULL) {
 174                                         PyErr_Clear();
 175                                         break;
 176                                 }
 177                                 if (PyString_Check(v)) {
 178                                         size_t len;
 179                                         len = PyString_Size(v);
 180                                         if (len + 1 + taillen >= MAXPATHLEN)
 181                                                 continue; /* Too long */
 182                                         strcpy(namebuf, PyString_AsString(v));
 183                                         if (strlen(namebuf) != len)
 184                                                 continue; /* v contains '\0' */
 185                                         if (len > 0 && namebuf[len-1] != SEP)
 186                                                 namebuf[len++] = SEP;
 187                                         strcpy(namebuf+len, tail);
 188                                         xfp = fopen(namebuf, "r" PY_STDIOTEXTMODE);
 189                                         if (xfp != NULL) {
 190                                                 filename = namebuf;
 191                                                 break;
 192                                         }
 193                                 }
 194                         }
 195                 }
 196         }
 197         PyOS_snprintf(linebuf, sizeof(linebuf), FMT, filename, lineno, name);
 198         err = PyFile_WriteString(linebuf, f);
 199         if (xfp == NULL || err != 0)
 200                 return err;
 201         for (i = 0; i < lineno; i++) {
 202                 char* pLastChar = &linebuf[sizeof(linebuf)-2];
 203                 do {
 204                         *pLastChar = '\0';
 205                         if (Py_UniversalNewlineFgets(linebuf, sizeof linebuf, xfp, NULL) == NULL)
 206                                 break;
 207                         /* fgets read *something*; if it didn't get as
 208                            far as pLastChar, it must have found a newline
 209                            or hit the end of the file;  if pLastChar is \n,
 210                            it obviously found a newline; else we haven't
 211                            yet seen a newline, so must continue */
 212                 } while (*pLastChar != '\0' && *pLastChar != '\n');
 213         }
 214         if (i == lineno) {
 215                 char *p = linebuf;
 216                 while (*p == ' ' || *p == '\t' || *p == '\014')
 217                         p++;
 218                 err = PyFile_WriteString("    ", f);
 219                 if (err == 0) {
 220                         err = PyFile_WriteString(p, f);
 221                         if (err == 0 && strchr(p, '\n') == NULL)
 222                                 err = PyFile_WriteString("\n", f);
 223                 }
 224         }
 225         fclose(xfp);
 226         return err;
 227 }
 228
 229 static int
 230 tb_printinternal(tracebackobject *tb, PyObject *f, int limit)
 231 {
 232         int err = 0;
 233         int depth = 0;
 234         tracebackobject *tb1 = tb;
 235         while (tb1 != NULL) {
 236                 depth++;
 237                 tb1 = tb1->tb_next;
 238         }
 239         while (tb != NULL && err == 0) {
 240                 if (depth <= limit) {
 241                         err = tb_displayline(f,
 242                             PyString_AsString(
 243                                     tb->tb_frame->f_code->co_filename),
 244                             tb->tb_lineno,
 245                             PyString_AsString(tb->tb_frame->f_code->co_name));
 246                 }
 247                 depth--;
 248                 tb = tb->tb_next;
 249                 if (err == 0)
 250                         err = PyErr_CheckSignals();
 251         }
 252         return err;
 253 }
 254
 255 int
 256 PyTraceBack_Print(PyObject *v, PyObject *f)
 257 {
 258         int err;
 259         PyObject *limitv;
 260         int limit = 1000;
 261         if (v == NULL)
 262                 return 0;
 263         if (!PyTraceBack_Check(v)) {
 264                 PyErr_BadInternalCall();
 265                 return -1;
 266         }
 267         limitv = PySys_GetObject("tracebacklimit");
 268         if (limitv && PyInt_Check(limitv)) {
 269                 limit = PyInt_AsLong(limitv);
 270                 if (limit <= 0)
 271                         return 0;
 272         }
 273         err = PyFile_WriteString("Traceback (most recent call last):\n", f);
 274         if (!err)
 275                 err = tb_printinternal((tracebackobject *)v, f, limit);
 276         return err;
 277 }