server/debug.c

   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 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <stdbool.h>
  38 #include <stdarg.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41 #include <errno.h>
  42
  43 #include "ansi-colours.h"
  44 #include "open_memstream.h"
  45
  46 #include "internal.h"
  47
  48 static void
  49 prologue (FILE *fp)
  50 {
  51   const char *name = threadlocal_get_name ();
  52   size_t instance_num = threadlocal_get_instance_num ();
  53
  54   fprintf (fp, "%s: ", program_name);
  55
  56   if (name) {
  57     fprintf (fp, "%s", name);
  58     if (instance_num > 0)
  59       fprintf (fp, "[%zu]", instance_num);
  60     fprintf (fp, ": ");
  61   }
  62
  63   fprintf (fp, "debug: ");
  64 }
  65
  66 /* Common debug function.
  67  * Note: preserves the previous value of errno.
  68  */
  69 static void
  70 debug_common (bool in_server, const char *fs, va_list args)
  71 {
  72   int err = errno;
  73   int tty;
  74   CLEANUP_FREE char *str = NULL;
  75   size_t len = 0;
  76   FILE *fp;
  77
  78   if (!verbose)
  79     return;
  80
  81   fp = open_memstream (&str, &len);
  82   if (fp == NULL) {
  83   fail:
  84     /* Try to emit what we can. */
  85     errno = err;
  86     vfprintf (stderr, fs, args);
  87     fprintf (stderr, "\n");
  88     return;
  89   }
  90
  91   tty = isatty (fileno (stderr));
  92   if (!in_server && tty) ansi_force_colour (ANSI_FG_BOLD_BLACK, fp);
  93
  94   prologue (fp);
  95
  96   errno = err;
  97   vfprintf (fp, fs, args);
  98
  99   if (!in_server && tty) ansi_force_restore (fp);
 100   fprintf (fp, "\n");
 101   close_memstream (fp);
 102
 103   if (str)
 104     fputs (str, stderr);
 105   else
 106     goto fail;
 107
 108   errno = err;
 109 }
 110
 111 /* Note: preserves the previous value of errno. */
 112 NBDKIT_DLL_PUBLIC void
 113 nbdkit_vdebug (const char *fs, va_list args)
 114 {
 115   debug_common (false, fs, args);
 116 }
 117
 118 /* Note: preserves the previous value of errno. */
 119 NBDKIT_DLL_PUBLIC void
 120 nbdkit_debug (const char *fs, ...)
 121 {
 122   int err = errno;
 123   va_list args;
 124
 125   va_start (args, fs);
 126   debug_common (false, fs, args);
 127   va_end (args);
 128
 129   errno = err;
 130 }
 131
 132 /* This variant of debug is used when debug is called from the server
 133  * code, via the debug() macro.
 134  *
 135  * Note: preserves the previous value of errno.
 136  */
 137 void
 138 debug_in_server (const char *fs, ...)
 139 {
 140   int err = errno;
 141   va_list args;
 142
 143   va_start (args, fs);
 144   debug_common (true, fs, args);
 145   va_end (args);
 146
 147   errno = err;
 148 }