src/lib/lttng-ust/tracelog-internal.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2013-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  * Copyright (C) 2021 Norbert Lange <nolange79@gmail.com>
   6  *
   7  * Shared helper macro for tracelog and tracef.
   8  */
   9
  10 #define LTTNG_UST_TRACELOG_VARARG(fmt, callback, ...) \
  11         do { \
  12                 char local_buf[LTTNG_TRACE_PRINTF_BUFSIZE]; \
  13                 char *alloc_buff = NULL, *msg = local_buf; \
  14                 size_t len = 0; \
  15                 va_list ap; \
  16 \
  17                 if (caa_unlikely(fmt[0] == '%' && fmt[1] == 's' && fmt[2] == '\0')) { \
  18                         va_start(ap, fmt); \
  19                         msg = va_arg(ap, char *); \
  20                         va_end(ap); \
  21                         len = strlen(msg); \
  22                 } else { \
  23                         size_t buflen = sizeof(local_buf); \
  24                         int ret; \
  25 \
  26                         /* On-stack buffer attempt */ \
  27                         va_start(ap, fmt); \
  28                         ret = vsnprintf(msg, buflen, fmt, ap); \
  29                         va_end(ap); \
  30                         if (caa_unlikely(ret < 0)) \
  31                                 break; \
  32                         len = (size_t)ret; \
  33 \
  34                         if (caa_unlikely(len >= sizeof(local_buf))) { \
  35                                 buflen = len + 1; \
  36                                 alloc_buff = (char *)malloc(buflen); \
  37                                 if (!alloc_buff) \
  38                                         goto end; \
  39                                 msg = alloc_buff; \
  40                                 va_start(ap, fmt); \
  41                                 ret = vsnprintf(msg, buflen, fmt, ap); \
  42                                 va_end(ap); \
  43                                 lttng_ust_runtime_bug_on(ret < 0 || (size_t)ret != buflen - 1); \
  44                                 len = (size_t)ret; \
  45                         } \
  46                 } \
  47 \
  48                 callback(__VA_ARGS__); \
  49 end: \
  50                 /* Don't call a potentially instrumented forbidden free needlessly. */ \
  51                 if (caa_unlikely(alloc_buff)) \
  52                         free(alloc_buff); \
  53         } while(0)
  54
  55 #define LTTNG_UST_TRACELOG_VALIST(fmt, ap, callback, ...) \
  56         do { \
  57                 char local_buf[LTTNG_TRACE_PRINTF_BUFSIZE]; \
  58                 char *alloc_buff = NULL, *msg = local_buf; \
  59                 size_t len = 0; \
  60 \
  61                 if (caa_unlikely(fmt[0] == '%' && fmt[1] == 's' && fmt[2] == '\0')) { \
  62                         msg = va_arg(ap, char *); \
  63                         len = strlen(msg); \
  64                 } else { \
  65                         size_t buflen = sizeof(local_buf); \
  66                         va_list ap2; \
  67                         int ret; \
  68 \
  69                         va_copy(ap2, ap); \
  70                         ret = vsnprintf(msg, buflen, fmt, ap2); \
  71                         va_end(ap2); \
  72                         if (caa_unlikely(ret < 0)) \
  73                                 break; \
  74                         len = (size_t)ret; \
  75 \
  76                         if (caa_unlikely(len >= sizeof(local_buf))) { \
  77                                 buflen = len + 1; \
  78                                 alloc_buff = (char *)malloc(buflen); \
  79                                 if (!alloc_buff) \
  80                                         goto end; \
  81                                 msg = alloc_buff; \
  82                                 ret = vsnprintf(msg, buflen, fmt, ap); \
  83                                 lttng_ust_runtime_bug_on(ret < 0 || (size_t)ret != buflen - 1); \
  84                                 len = (size_t)ret; \
  85                         } \
  86                 } \
  87 \
  88                 callback(__VA_ARGS__); \
  89 end: \
  90                 /* Don't call a potentially instrumented forbidden free needlessly. */ \
  91                 if (caa_unlikely(alloc_buff)) \
  92                         free(alloc_buff); \
  93         } while (0)