include/openssl/trace.h

   1 /*
   2  * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #ifndef OSSL_TRACE_H
  11 # define OSSL_TRACE_H
  12
  13 # include <stdarg.h>
  14
  15 # include <openssl/bio.h>
  16
  17 # ifdef  __cplusplus
  18 extern "C" {
  19 # endif
  20
  21 /*
  22  * TRACE CATEGORIES
  23  */
  24
  25 /*
  26  * The trace messages of the OpenSSL libraries are organized into different
  27  * categories. For every trace category, the application can register a separate
  28  * tracer callback. When a callback is registered, a so called trace channel is
  29  * created for this category. This channel consists essentially of an internal
  30  * BIO which sends all trace output it receives to the registered application
  31  * callback.
  32  *
  33  * The ANY category is used as a fallback category.
  34  */
  35 # define OSSL_TRACE_CATEGORY_ANY                 0 /* The fallback */
  36 # define OSSL_TRACE_CATEGORY_TLS                 1
  37 # define OSSL_TRACE_CATEGORY_NUM                 2
  38
  39 /* Returns the trace category number for the given |name| */
  40 int OSSL_trace_get_category_num(const char *name);
  41
  42 /* Returns the trace category name for the given |num| */
  43 const char *OSSL_trace_get_category_name(int num);
  44
  45 /*
  46  * TRACE CONSUMERS
  47  */
  48
  49 /*
  50  * Enables tracing for the given |category| by providing a BIO sink
  51  * as |channel|. If a null pointer is passed as |channel|, an existing
  52  * trace channel is removed and tracing for the category is disabled.
  53  *
  54  * Returns 1 on success and 0 on failure
  55  */
  56 int OSSL_trace_set_channel(int category, BIO* channel);
  57
  58 /*
  59  * Attach a prefix and a suffix to the given |category|, to be printed at the
  60  * beginning and at the end of each trace output group, i.e. when
  61  * OSSL_trace_begin() and OSSL_trace_end() are called.
  62  * If a null pointer is passed as argument, the existing prefix or suffix is
  63  * removed.
  64  *
  65  * They return 1 on success and 0 on failure
  66  */
  67 int OSSL_trace_set_prefix(int category, const char *prefix);
  68 int OSSL_trace_set_suffix(int category, const char *suffix);
  69
  70 /*
  71  * OSSL_trace_cb is the type tracing callback provided by the application.
  72  * It MUST return the number of bytes written, or 0 on error (in other words,
  73  * it can never write zero bytes).
  74  *
  75  * The |buffer| will always contain text, which may consist of several lines.
  76  * The |data| argument points to whatever data was provided by the application
  77  * when registering the tracer function.
  78  *
  79  * The |category| number is given, as well as a |cmd| number, described below.
  80  */
  81 typedef size_t (*OSSL_trace_cb)(const char *buffer, size_t count,
  82                                 int category, int cmd, void *data);
  83 /*
  84  * Possible |cmd| numbers.
  85  */
  86 # define OSSL_TRACE_CTRL_BEGIN  0
  87 # define OSSL_TRACE_CTRL_DURING 1
  88 # define OSSL_TRACE_CTRL_END    2
  89
  90 /*
  91  * Enables tracing for the given |category| by creating an internal
  92  * trace channel which sends the output to the given |callback|.
  93  * If a null pointer is passed as callback, an existing trace channel
  94  * is removed and tracing for the category is disabled.
  95  *
  96  * NOTE: OSSL_trace_set_channel() and OSSL_trace_set_callback() are mutually
  97  *       exclusive.
  98  *
  99  * Returns 1 on success and 0 on failure
 100  */
 101 int OSSL_trace_set_callback(int category, OSSL_trace_cb callback, void *data);
 102
 103 /*
 104  * TRACE PRODUCERS
 105  */
 106
 107 /*
 108  * Returns 1 if tracing for the specified category is enabled, otherwise 0
 109  */
 110 int OSSL_trace_enabled(int category);
 111
 112 /*
 113  * Wrap a group of tracing output calls.  OSSL_trace_begin() locks tracing and
 114  * returns the trace channel associated with the given category, or NULL if no
 115  * channel is associated with the category.  OSSL_trace_end() unlocks tracing.
 116  *
 117  * Usage:
 118  *
 119  *    BIO *out;
 120  *    if ((out = OSSL_trace_begin(category)) != NULL) {
 121  *        ...
 122  *        BIO_fprintf(out, ...);
 123  *        ...
 124  *        OSSL_trace_end(category, out);
 125  *    }
 126  *
 127  * See also the convenience macros OSSL_TRACE_BEGIN and OSSL_TRACE_END below.
 128  */
 129 BIO *OSSL_trace_begin(int category);
 130 void OSSL_trace_end(int category, BIO *channel);
 131
 132 /*
 133  * OSSL_TRACE* Convenience Macros
 134  */
 135
 136 /*
 137  * When the tracing feature is disabled, these macros are defined to
 138  * produce dead code, which a good compiler should eliminate.
 139  */
 140
 141 /*
 142  * OSSL_TRACE_BEGIN, OSSL_TRACE_END - Define a Trace Group
 143  *
 144  * These two macros can be used to create a block which is executed only
 145  * if the corresponding trace category is enabled. Inside this block, a
 146  * local variable named |trc_out| is defined, which points to the channel
 147  * associated with the given trace category.
 148  *
 149  * Usage: (using 'TLS' as an example category)
 150  *
 151  *     OSSL_TRACE_BEGIN(TLS) {
 152  *
 153  *         BIO_fprintf(trc_out, ... );
 154  *
 155  *     } OSSL_TRACE_END(TLS);
 156  *
 157  *
 158  * This expands to the following code
 159  *
 160  *     do {
 161  *         BIO *trc_out = OSSL_trace_begin(OSSL_TRACE_CATEGORY_TLS);
 162  *         if (trc_out != NULL) {
 163  *             ...
 164  *             BIO_fprintf(trc_out, ...);
 165  *         }
 166  *         OSSL_trace_end(OSSL_TRACE_CATEGORY_TLS, trc_out);
 167  *     } while (0);
 168  *
 169  * The use of the inner '{...}' group and the trailing ';' is enforced
 170  * by the definition of the macros in order to make the code look as much
 171  * like C code as possible.
 172  *
 173  * Before returning from inside the trace block, it is necessary to
 174  * call OSSL_TRACE_CANCEL(category).
 175  */
 176
 177 # ifndef OPENSSL_NO_TRACE
 178
 179 #  define OSSL_TRACE_BEGIN(category) \
 180     do { \
 181         BIO *trc_out = OSSL_trace_begin(OSSL_TRACE_CATEGORY_##category); \
 182  \
 183         if (trc_out != NULL)
 184
 185 #  define OSSL_TRACE_END(category) \
 186         OSSL_trace_end(OSSL_TRACE_CATEGORY_##category, trc_out); \
 187     } while (0)
 188
 189 #  define OSSL_TRACE_CANCEL(category) \
 190         OSSL_trace_end(OSSL_TRACE_CATEGORY_##category, trc_out) \
 191
 192 # else
 193
 194 #  define OSSL_TRACE_BEGIN(category)           \
 195     do {                                        \
 196         BIO *trc_out = NULL;                    \
 197         if (0)
 198
 199 #  define OSSL_TRACE_END(category)             \
 200     } while(0)
 201
 202 #  define OSSL_TRACE_CANCEL(category)          \
 203     ((void)0)
 204
 205 # endif
 206
 207 /*
 208  * OSSL_TRACE_ENABLED() - Check whether tracing is enabled for |category|
 209  *
 210  * Usage:
 211  *
 212  *     if (OSSL_TRACE_ENABLED(TLS)) {
 213  *         ...
 214  *     }
 215  */
 216 # ifndef OPENSSL_NO_TRACE
 217
 218 #  define OSSL_TRACE_ENABLED(category) \
 219     OSSL_trace_enabled(OSSL_TRACE_CATEGORY_##category)
 220
 221 # else
 222
 223 #  define OSSL_TRACE_ENABLED(category) (0)
 224
 225 # endif
 226
 227 /*
 228  * OSSL_TRACE*() - OneShot Trace Macros
 229  *
 230  * These macros are intended to produce a simple printf-style trace output.
 231  * Unfortunately, C90 macros don't support variable arguments, so the
 232  * "vararg" OSSL_TRACEV() macro has a rather weird usage pattern:
 233  *
 234  *    OSSL_TRACEV(category, (trc_out, "format string", ...args...));
 235  *
 236  * Where 'channel' is the literal symbol of this name, not a variable.
 237  * For that reason, it is currently not intended to be used directly,
 238  * but only as helper macro for the other oneshot trace macros
 239  * OSSL_TRACE(), OSSL_TRACE1(), OSSL_TRACE2(), ...
 240  *
 241  * Usage:
 242  *
 243  *    OSSL_TRACE(INIT, "Hello world!\n");
 244  *    OSSL_TRACE1(TLS, "The answer is %d\n", 42);
 245  *    OSSL_TRACE2(TLS, "The ultimate question to answer %d is '%s'\n",
 246  *                42, "What do you get when you multiply six by nine?");
 247  */
 248
 249 # define OSSL_TRACEV(category, args) \
 250     OSSL_TRACE_BEGIN(category) \
 251         BIO_printf args; \
 252     OSSL_TRACE_END(category)
 253
 254 # define OSSL_TRACE(category, text) \
 255     OSSL_TRACEV(category, (trc_out, "%s", text))
 256
 257 # define OSSL_TRACE1(category, format, arg1) \
 258     OSSL_TRACEV(category, (trc_out, format, arg1))
 259 # define OSSL_TRACE2(category, format, arg1, arg2) \
 260     OSSL_TRACEV(category, (trc_out, format, arg1, arg2))
 261 # define OSSL_TRACE3(category, format, arg1, arg2, arg3) \
 262     OSSL_TRACEV(category, (trc_out, format, arg1, arg2, arg3))
 263 # define OSSL_TRACE4(category, format, arg1, arg2, arg3, arg4) \
 264     OSSL_TRACEV(category, (trc_out, format, arg1, arg2, arg3, arg4))
 265 # define OSSL_TRACE5(category, format, arg1, arg2, arg3, arg4, arg5) \
 266     OSSL_TRACEV(category, (trc_out, format, arg1, arg2, arg3, arg4, arg5))
 267 # define OSSL_TRACE6(category, format, arg1, arg2, arg3, arg4, arg5, arg6) \
 268     OSSL_TRACEV(category, (trc_out, format, arg1, arg2, arg3, arg4, arg5, arg6))
 269 # define OSSL_TRACE7(category, format, arg1, arg2, arg3, arg4, arg5, arg6, arg7) \
 270     OSSL_TRACEV(category, (trc_out, format, arg1, arg2, arg3, arg4, arg5, arg6, arg7))
 271 # define OSSL_TRACE8(category, format, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) \
 272     OSSL_TRACEV(category, (trc_out, format, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8))
 273 # define OSSL_TRACE9(category, format, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) \
 274     OSSL_TRACEV(category, (trc_out, format, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9))
 275
 276 # ifdef  __cplusplus
 277 }
 278 # endif
 279
 280 #endif