filters/log/log.h

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef NBDKIT_LOG_H
  34 #define NBDKIT_LOG_H
  35
  36 #include <stdint.h>
  37 #include <stdarg.h>
  38
  39 #include <pthread.h>
  40
  41 #include <nbdkit-filter.h>
  42
  43 typedef uint64_t log_id_t;
  44
  45 struct handle {
  46   uint64_t connection;
  47   log_id_t id;
  48   const char *exportname;
  49   int tls;
  50 };
  51
  52 extern uint64_t connections;
  53 extern const char *logfilename;
  54 extern FILE *logfile;
  55 extern const char *logscript;
  56 extern int append;
  57 extern pthread_mutex_t lock;
  58
  59 /* Compute the next id number on the current connection. */
  60 static inline log_id_t
  61 get_id (struct handle *h)
  62 {
  63   ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock);
  64   return ++h->id;
  65 }
  66
  67 /* enter() and leave() are called on entry and exit to every filter
  68  * method and handle the logging.
  69  *
  70  * Some methods (like .prepare) only print() a single mssage.
  71  */
  72 extern void enter (struct handle *h, log_id_t id, const char *act,
  73                    const char *fmt, ...)
  74   ATTRIBUTE_FORMAT_PRINTF (4, 5);
  75 extern void leave (struct handle *h, log_id_t id, const char *act,
  76                    const char *fmt, ...)
  77   ATTRIBUTE_FORMAT_PRINTF (4, 5);
  78 extern void print (struct handle *h, const char *act,
  79                    const char *fmt, ...)
  80   ATTRIBUTE_FORMAT_PRINTF (3, 4);
  81
  82 /* In the case where leave() only has to print result-or-error, this
  83  * simplified version is used instead.
  84  */
  85 extern void leave_simple (struct handle *h, log_id_t id, const char *act,
  86                           int r, int *err);
  87
  88 /* For simple methods, define a macro which automatically calls
  89  * enter() on entry, and leave_simple() on each exit path.
  90  */
  91 struct leave_simple_params {
  92   struct handle *h;
  93   log_id_t id;
  94   const char *act;
  95   int *r;
  96   int *err;
  97 };
  98
  99 extern void leave_simple2 (struct leave_simple_params *params);
 100
 101 #define LOG(h, act, r, err, ...)                                        \
 102   log_id_t id = get_id (h);                                             \
 103   __attribute__ ((cleanup (leave_simple2)))                             \
 104   CLANG_UNUSED_VARIABLE_WORKAROUND                                      \
 105   struct leave_simple_params _params = { h, id, act, &r, err };         \
 106   enter ((h), id, (act), ##__VA_ARGS__)
 107
 108 #endif /* NBDKIT_LOG_H */