Guido van Rossum | f70e43a | 1991-02-19 12:39:46 +0000 | [diff] [blame] | 1 | /*********************************************************** |
Guido van Rossum | 3a24181 | 1994-08-29 12:14:12 +0000 | [diff] [blame] | 2 | Copyright 1991, 1992, 1993, 1994 by Stichting Mathematisch Centrum, |
Guido van Rossum | e537240 | 1993-03-16 12:15:04 +0000 | [diff] [blame] | 3 | Amsterdam, The Netherlands. |
Guido van Rossum | f70e43a | 1991-02-19 12:39:46 +0000 | [diff] [blame] | 4 | |
| 5 | All Rights Reserved |
| 6 | |
| 7 | Permission to use, copy, modify, and distribute this software and its |
| 8 | documentation for any purpose and without fee is hereby granted, |
| 9 | provided that the above copyright notice appear in all copies and that |
| 10 | both that copyright notice and this permission notice appear in |
| 11 | supporting documentation, and that the names of Stichting Mathematisch |
| 12 | Centrum or CWI not be used in advertising or publicity pertaining to |
| 13 | distribution of the software without specific, written prior permission. |
| 14 | |
| 15 | STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO |
| 16 | THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND |
| 17 | FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE |
| 18 | FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 19 | WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 20 | ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
| 21 | OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| 22 | |
| 23 | ******************************************************************/ |
| 24 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 25 | /* Error handling -- see also run.c */ |
| 26 | |
| 27 | /* New error handling interface. |
| 28 | |
| 29 | The following problem exists (existed): methods of built-in modules |
| 30 | are called with 'self' and 'args' arguments, but without a context |
| 31 | argument, so they have no way to raise a specific exception. |
| 32 | The same is true for the object implementations: no context argument. |
| 33 | The old convention was to set 'errno' and to return NULL. |
| 34 | The caller (usually call_function() in eval.c) detects the NULL |
| 35 | return value and then calls puterrno(ctx) to turn the errno value |
| 36 | into a true exception. Problems with this approach are: |
| 37 | - it used standard errno values to indicate Python-specific errors, |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 38 | but this means that when such an error code is reported by a system |
| 39 | call (e.g., in module posix), the user gets a confusing message |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 40 | - errno is a global variable, which makes extensions to a multi- |
| 41 | threading environment difficult; e.g., in IRIX, multi-threaded |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 42 | programs must use the function oserror() instead of looking in errno |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 43 | - there is no portable way to add new error numbers for specic |
| 44 | situations -- the value space for errno is reserved to the OS, yet |
| 45 | the way to turn module-specific errors into a module-specific |
| 46 | exception requires module-specific values for errno |
| 47 | - there is no way to add a more situation-specific message to an |
| 48 | error. |
| 49 | |
| 50 | The new interface solves all these problems. To return an error, a |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 51 | built-in function calls err_set(exception), err_setval(exception, |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 52 | value) or err_setstr(exception, string), and returns NULL. These |
| 53 | functions save the value for later use by puterrno(). To adapt this |
| 54 | scheme to a multi-threaded environment, only the implementation of |
| 55 | err_setval() has to be changed. |
| 56 | */ |
| 57 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 58 | #include "allobjects.h" |
Guido van Rossum | 6989e54 | 1994-09-29 09:39:39 +0000 | [diff] [blame^] | 59 | #include "traceback.h" |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 60 | |
Guido van Rossum | f22120a | 1990-12-20 23:05:40 +0000 | [diff] [blame] | 61 | #include <errno.h> |
Guido van Rossum | f22120a | 1990-12-20 23:05:40 +0000 | [diff] [blame] | 62 | |
Guido van Rossum | f5401bd | 1990-11-02 17:50:28 +0000 | [diff] [blame] | 63 | extern char *strerror PROTO((int)); |
| 64 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 65 | /* Last exception stored by err_setval() */ |
| 66 | |
| 67 | static object *last_exception; |
| 68 | static object *last_exc_val; |
| 69 | |
| 70 | void |
| 71 | err_setval(exception, value) |
| 72 | object *exception; |
| 73 | object *value; |
| 74 | { |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 75 | XDECREF(last_exception); |
| 76 | XINCREF(exception); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 77 | last_exception = exception; |
| 78 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 79 | XDECREF(last_exc_val); |
| 80 | XINCREF(value); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 81 | last_exc_val = value; |
| 82 | } |
| 83 | |
| 84 | void |
| 85 | err_set(exception) |
| 86 | object *exception; |
| 87 | { |
| 88 | err_setval(exception, (object *)NULL); |
| 89 | } |
| 90 | |
| 91 | void |
| 92 | err_setstr(exception, string) |
| 93 | object *exception; |
| 94 | char *string; |
| 95 | { |
| 96 | object *value = newstringobject(string); |
| 97 | err_setval(exception, value); |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 98 | XDECREF(value); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 99 | } |
| 100 | |
Guido van Rossum | 3a24181 | 1994-08-29 12:14:12 +0000 | [diff] [blame] | 101 | |
| 102 | object * |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 103 | err_occurred() |
| 104 | { |
Guido van Rossum | 3a24181 | 1994-08-29 12:14:12 +0000 | [diff] [blame] | 105 | return last_exception; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 106 | } |
| 107 | |
| 108 | void |
| 109 | err_get(p_exc, p_val) |
| 110 | object **p_exc; |
| 111 | object **p_val; |
| 112 | { |
| 113 | *p_exc = last_exception; |
| 114 | last_exception = NULL; |
| 115 | *p_val = last_exc_val; |
| 116 | last_exc_val = NULL; |
| 117 | } |
| 118 | |
| 119 | void |
| 120 | err_clear() |
| 121 | { |
Guido van Rossum | 6989e54 | 1994-09-29 09:39:39 +0000 | [diff] [blame^] | 122 | object *tb; |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 123 | XDECREF(last_exception); |
| 124 | last_exception = NULL; |
| 125 | XDECREF(last_exc_val); |
| 126 | last_exc_val = NULL; |
Guido van Rossum | 6989e54 | 1994-09-29 09:39:39 +0000 | [diff] [blame^] | 127 | /* Also clear interpreter stack trace */ |
| 128 | tb = tb_fetch(); |
| 129 | XDECREF(tb); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 130 | } |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 131 | |
| 132 | /* Convenience functions to set a type error exception and return 0 */ |
| 133 | |
| 134 | int |
| 135 | err_badarg() |
| 136 | { |
Guido van Rossum | f1ac403 | 1990-11-09 15:05:53 +0000 | [diff] [blame] | 137 | err_setstr(TypeError, "illegal argument type for built-in operation"); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 138 | return 0; |
| 139 | } |
| 140 | |
| 141 | object * |
| 142 | err_nomem() |
| 143 | { |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 144 | err_set(MemoryError); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 145 | return NULL; |
| 146 | } |
| 147 | |
| 148 | object * |
| 149 | err_errno(exc) |
| 150 | object *exc; |
| 151 | { |
Guido van Rossum | 5063bab | 1991-10-20 20:14:56 +0000 | [diff] [blame] | 152 | object *v; |
Guido van Rossum | 3a24181 | 1994-08-29 12:14:12 +0000 | [diff] [blame] | 153 | int i = errno; |
| 154 | if (i == EINTR && sigcheck()) |
Guido van Rossum | 5063bab | 1991-10-20 20:14:56 +0000 | [diff] [blame] | 155 | return NULL; |
Guido van Rossum | 3a24181 | 1994-08-29 12:14:12 +0000 | [diff] [blame] | 156 | v = mkvalue("(is)", i, strerror(i)); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 157 | if (v != NULL) { |
Guido van Rossum | e537240 | 1993-03-16 12:15:04 +0000 | [diff] [blame] | 158 | err_setval(exc, v); |
| 159 | DECREF(v); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 160 | } |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 161 | return NULL; |
| 162 | } |
Guido van Rossum | 683a072 | 1990-10-21 22:09:12 +0000 | [diff] [blame] | 163 | |
| 164 | void |
| 165 | err_badcall() |
| 166 | { |
| 167 | err_setstr(SystemError, "bad argument to internal function"); |
| 168 | } |