glib/glib-init.c

   1 /*
   2  * Copyright © 2011 Canonical Limited
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Author: Ryan Lortie <desrt@desrt.ca>
  18  */
  19
  20 #include "config.h"
  21
  22 #include "glib-init.h"
  23
  24 #include "glib-private.h"
  25 #include "gtypes.h"
  26 #include "gutils.h"     /* for GDebugKey */
  27 #include "gconstructor.h"
  28 #include "gmem.h"       /* for g_mem_gc_friendly */
  29
  30 #include <string.h>
  31 #include <stdlib.h>
  32 #include <stdio.h>
  33 #include <ctype.h>
  34
  35 /* This seems as good a place as any to make static assertions about platform
  36  * assumptions we make throughout GLib. */
  37
  38 /* We do not support 36-bit bytes or other historical curiosities. */
  39 G_STATIC_ASSERT (CHAR_BIT == 8);
  40
  41 /* We assume that data pointers are the same size as function pointers... */
  42 G_STATIC_ASSERT (sizeof (gpointer) == sizeof (GFunc));
  43 G_STATIC_ASSERT (_g_alignof (gpointer) == _g_alignof (GFunc));
  44 /* ... and that all function pointers are the same size. */
  45 G_STATIC_ASSERT (sizeof (GFunc) == sizeof (GCompareDataFunc));
  46 G_STATIC_ASSERT (_g_alignof (GFunc) == _g_alignof (GCompareDataFunc));
  47
  48 /* We assume that "small" enums (those where all values fit in INT32_MIN
  49  * to INT32_MAX) are exactly int-sized. In particular, we assume that if
  50  * an enum has no members that exceed the range of char/short, the
  51  * compiler will make it int-sized anyway, so adding a member later that
  52  * *does* exceed the range of char/short is not an ABI break. */
  53 typedef enum {
  54     TEST_CHAR_0 = 0
  55 } TestChar;
  56 typedef enum {
  57     TEST_SHORT_0 = 0,
  58     TEST_SHORT_256 = 256
  59 } TestShort;
  60 typedef enum {
  61     TEST_INT32_MIN = G_MININT32,
  62     TEST_INT32_MAX = G_MAXINT32
  63 } TestInt;
  64 G_STATIC_ASSERT (sizeof (TestChar) == sizeof (int));
  65 G_STATIC_ASSERT (sizeof (TestShort) == sizeof (int));
  66 G_STATIC_ASSERT (sizeof (TestInt) == sizeof (int));
  67 G_STATIC_ASSERT (_g_alignof (TestChar) == _g_alignof (int));
  68 G_STATIC_ASSERT (_g_alignof (TestShort) == _g_alignof (int));
  69 G_STATIC_ASSERT (_g_alignof (TestInt) == _g_alignof (int));
  70
  71 /**
  72  * g_mem_gc_friendly:
  73  *
  74  * This variable is %TRUE if the `G_DEBUG` environment variable
  75  * includes the key `gc-friendly`.
  76  */
  77 gboolean g_mem_gc_friendly = FALSE;
  78
  79 GLogLevelFlags g_log_msg_prefix = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_WARNING |
  80                                   G_LOG_LEVEL_CRITICAL | G_LOG_LEVEL_DEBUG;
  81 GLogLevelFlags g_log_always_fatal = G_LOG_FATAL_MASK;
  82
  83 static gboolean
  84 debug_key_matches (const gchar *key,
  85                    const gchar *token,
  86                    guint        length)
  87 {
  88   /* may not call GLib functions: see note in g_parse_debug_string() */
  89   for (; length; length--, key++, token++)
  90     {
  91       char k = (*key   == '_') ? '-' : tolower (*key  );
  92       char t = (*token == '_') ? '-' : tolower (*token);
  93
  94       if (k != t)
  95         return FALSE;
  96     }
  97
  98   return *key == '\0';
  99 }
 100
 101 /* The GVariant documentation indirectly says that int is at least 32 bits
 102  * (by saying that b, y, n, q, i, u, h are promoted to int). On any
 103  * reasonable platform, int is in fact *exactly* 32 bits long, because
 104  * otherwise, {signed char, short, int} wouldn't be sufficient to provide
 105  * {int8_t, int16_t, int32_t}. */
 106 G_STATIC_ASSERT (sizeof (int) == sizeof (gint32));
 107
 108 /**
 109  * g_parse_debug_string:
 110  * @string: (nullable): a list of debug options separated by colons, spaces, or
 111  * commas, or %NULL.
 112  * @keys: (array length=nkeys): pointer to an array of #GDebugKey which associate
 113  *     strings with bit flags.
 114  * @nkeys: the number of #GDebugKeys in the array.
 115  *
 116  * Parses a string containing debugging options
 117  * into a %guint containing bit flags. This is used
 118  * within GDK and GTK+ to parse the debug options passed on the
 119  * command line or through environment variables.
 120  *
 121  * If @string is equal to "all", all flags are set. Any flags
 122  * specified along with "all" in @string are inverted; thus,
 123  * "all,foo,bar" or "foo,bar,all" sets all flags except those
 124  * corresponding to "foo" and "bar".
 125  *
 126  * If @string is equal to "help", all the available keys in @keys
 127  * are printed out to standard error.
 128  *
 129  * Returns: the combined set of bit flags.
 130  */
 131 guint
 132 g_parse_debug_string  (const gchar     *string,
 133                        const GDebugKey *keys,
 134                        guint            nkeys)
 135 {
 136   guint i;
 137   guint result = 0;
 138
 139   if (string == NULL)
 140     return 0;
 141
 142   /* this function is used during the initialisation of gmessages, gmem
 143    * and gslice, so it may not do anything that causes memory to be
 144    * allocated or risks messages being emitted.
 145    *
 146    * this means, more or less, that this code may not call anything
 147    * inside GLib.
 148    */
 149
 150   if (!strcasecmp (string, "help"))
 151     {
 152       /* using stdio directly for the reason stated above */
 153       fprintf (stderr, "Supported debug values:");
 154       for (i = 0; i < nkeys; i++)
 155         fprintf (stderr, " %s", keys[i].key);
 156       fprintf (stderr, " all help\n");
 157     }
 158   else
 159     {
 160       const gchar *p = string;
 161       const gchar *q;
 162       gboolean invert = FALSE;
 163
 164       while (*p)
 165        {
 166          q = strpbrk (p, ":;, \t");
 167          if (!q)
 168            q = p + strlen (p);
 169
 170          if (debug_key_matches ("all", p, q - p))
 171            {
 172              invert = TRUE;
 173            }
 174          else
 175            {
 176              for (i = 0; i < nkeys; i++)
 177                if (debug_key_matches (keys[i].key, p, q - p))
 178                  result |= keys[i].value;
 179            }
 180
 181          p = q;
 182          if (*p)
 183            p++;
 184        }
 185
 186       if (invert)
 187         {
 188           guint all_flags = 0;
 189
 190           for (i = 0; i < nkeys; i++)
 191             all_flags |= keys[i].value;
 192
 193           result = all_flags & (~result);
 194         }
 195     }
 196
 197   return result;
 198 }
 199
 200 static guint
 201 g_parse_debug_envvar (const gchar     *envvar,
 202                       const GDebugKey *keys,
 203                       gint             n_keys,
 204                       guint            default_value)
 205 {
 206   const gchar *value;
 207
 208 #ifdef OS_WIN32
 209   /* "fatal-warnings,fatal-criticals,all,help" is pretty short */
 210   gchar buffer[100];
 211
 212   if (GetEnvironmentVariable (envvar, buffer, 100) < 100)
 213     value = buffer;
 214   else
 215     return 0;
 216 #else
 217   value = getenv (envvar);
 218 #endif
 219
 220   if (value == NULL)
 221     return default_value;
 222
 223   return g_parse_debug_string (value, keys, n_keys);
 224 }
 225
 226 static void
 227 g_messages_prefixed_init (void)
 228 {
 229   const GDebugKey keys[] = {
 230     { "error", G_LOG_LEVEL_ERROR },
 231     { "critical", G_LOG_LEVEL_CRITICAL },
 232     { "warning", G_LOG_LEVEL_WARNING },
 233     { "message", G_LOG_LEVEL_MESSAGE },
 234     { "info", G_LOG_LEVEL_INFO },
 235     { "debug", G_LOG_LEVEL_DEBUG }
 236   };
 237
 238   g_log_msg_prefix = g_parse_debug_envvar ("G_MESSAGES_PREFIXED", keys, G_N_ELEMENTS (keys), g_log_msg_prefix);
 239 }
 240
 241 static void
 242 g_debug_init (void)
 243 {
 244   const GDebugKey keys[] = {
 245     { "gc-friendly", 1 },
 246     {"fatal-warnings",  G_LOG_LEVEL_WARNING | G_LOG_LEVEL_CRITICAL },
 247     {"fatal-criticals", G_LOG_LEVEL_CRITICAL }
 248   };
 249   GLogLevelFlags flags;
 250
 251   flags = g_parse_debug_envvar ("G_DEBUG", keys, G_N_ELEMENTS (keys), 0);
 252
 253   g_log_always_fatal |= flags & G_LOG_LEVEL_MASK;
 254
 255   g_mem_gc_friendly = flags & 1;
 256 }
 257
 258 void
 259 glib_init (void)
 260 {
 261   static gboolean glib_inited;
 262
 263   if (glib_inited)
 264     return;
 265
 266   glib_inited = TRUE;
 267
 268   g_messages_prefixed_init ();
 269   g_debug_init ();
 270   g_quark_init ();
 271 }
 272
 273 #if defined (G_OS_WIN32)
 274
 275 BOOL WINAPI DllMain (HINSTANCE hinstDLL,
 276                      DWORD     fdwReason,
 277                      LPVOID    lpvReserved);
 278
 279 HMODULE glib_dll;
 280
 281 BOOL WINAPI
 282 DllMain (HINSTANCE hinstDLL,
 283          DWORD     fdwReason,
 284          LPVOID    lpvReserved)
 285 {
 286   switch (fdwReason)
 287     {
 288     case DLL_PROCESS_ATTACH:
 289       glib_dll = hinstDLL;
 290       g_clock_win32_init ();
 291 #ifdef THREADS_WIN32
 292       g_thread_win32_init ();
 293 #endif
 294       glib_init ();
 295       break;
 296
 297     case DLL_THREAD_DETACH:
 298 #ifdef THREADS_WIN32
 299       g_thread_win32_thread_detach ();
 300 #endif
 301       break;
 302
 303     case DLL_PROCESS_DETACH:
 304 #ifdef THREADS_WIN32
 305       if (lpvReserved == NULL)
 306         g_thread_win32_process_detach ();
 307 #endif
 308       break;
 309
 310     default:
 311       /* do nothing */
 312       ;
 313     }
 314
 315   return TRUE;
 316 }
 317
 318 #elif defined (G_HAS_CONSTRUCTORS)
 319
 320 #ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
 321 #pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(glib_init_ctor)
 322 #endif
 323 G_DEFINE_CONSTRUCTOR(glib_init_ctor)
 324
 325 static void
 326 glib_init_ctor (void)
 327 {
 328   glib_init ();
 329 }
 330
 331 #else
 332 # error Your platform/compiler is missing constructor support
 333 #endif