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