1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-internals.c random utility stuff (internal to D-Bus implementation)
4 * Copyright (C) 2002, 2003 Red Hat, Inc.
6 * Licensed under the Academic Free License version 2.1
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 #include "dbus-internals.h"
24 #include "dbus-protocol.h"
25 #include "dbus-marshal-basic.h"
26 #include "dbus-test.h"
33 * @defgroup DBusInternals D-Bus secret internal implementation details
34 * @brief Documentation useful when developing or debugging D-Bus itself.
39 * @defgroup DBusInternalsUtils Utilities and portability
40 * @ingroup DBusInternals
41 * @brief Utility functions (_dbus_assert(), _dbus_warn(), etc.)
48 * Aborts with an error message if the condition is false.
50 * @param condition condition which must be true.
54 * @def _dbus_assert_not_reached
56 * Aborts with an error message if called.
57 * The given explanation will be printed.
59 * @param explanation explanation of what happened if the code was reached.
63 * @def _DBUS_N_ELEMENTS
65 * Computes the number of elements in a fixed-size array using
68 * @param array the array to count elements in.
72 * @def _DBUS_POINTER_TO_INT
74 * Safely casts a void* to an integer; should only be used on void*
75 * that actually contain integers, for example one created with
76 * _DBUS_INT_TO_POINTER. Only guaranteed to preserve 32 bits.
77 * (i.e. it's used to store 32-bit ints in pointers, but
78 * can't be used to store 64-bit pointers in ints.)
80 * @param pointer pointer to extract an integer from.
83 * @def _DBUS_INT_TO_POINTER
85 * Safely stuffs an integer into a pointer, to be extracted later with
86 * _DBUS_POINTER_TO_INT. Only guaranteed to preserve 32 bits.
88 * @param integer the integer to stuff into a pointer.
93 * Sets all bits in an object to zero.
95 * @param object the object to be zeroed.
98 * @def _DBUS_INT16_MIN
100 * Minimum value of type "int16"
103 * @def _DBUS_INT16_MAX
105 * Maximum value of type "int16"
108 * @def _DBUS_UINT16_MAX
110 * Maximum value of type "uint16"
114 * @def _DBUS_INT32_MIN
116 * Minimum value of type "int32"
119 * @def _DBUS_INT32_MAX
121 * Maximum value of type "int32"
124 * @def _DBUS_UINT32_MAX
126 * Maximum value of type "uint32"
132 * Minimum value of type "int"
137 * Maximum value of type "int"
140 * @def _DBUS_UINT_MAX
142 * Maximum value of type "uint"
146 * @typedef DBusForeachFunction
148 * Used to iterate over each item in a collection, such as
153 * @def _DBUS_LOCK_NAME
155 * Expands to name of a global lock variable.
159 * @def _DBUS_DEFINE_GLOBAL_LOCK
161 * Defines a global lock variable with the given name.
162 * The lock must be added to the list to initialize
163 * in dbus_threads_init().
167 * @def _DBUS_DECLARE_GLOBAL_LOCK
169 * Expands to declaration of a global lock defined
170 * with _DBUS_DEFINE_GLOBAL_LOCK.
171 * The lock must be added to the list to initialize
172 * in dbus_threads_init().
178 * Locks a global lock
184 * Unlocks a global lock
188 * Fixed "out of memory" error message, just to avoid
189 * making up a different string every time and wasting
192 const char _dbus_no_memory_message[] = "Not enough memory";
194 static dbus_bool_t warn_initted = FALSE;
195 static dbus_bool_t fatal_warnings = FALSE;
196 static dbus_bool_t fatal_warnings_on_check_failed = TRUE;
204 s = _dbus_getenv ("DBUS_FATAL_WARNINGS");
209 fatal_warnings = FALSE;
210 fatal_warnings_on_check_failed = FALSE;
214 fatal_warnings = TRUE;
215 fatal_warnings_on_check_failed = TRUE;
219 fprintf(stderr, "DBUS_FATAL_WARNINGS should be set to 0 or 1 if set, not '%s'",
229 * Prints a warning message to stderr. Can optionally be made to exit
230 * fatally by setting DBUS_FATAL_WARNINGS, but this is rarely
231 * used. This function should be considered pretty much equivalent to
232 * fprintf(stderr). _dbus_warn_check_failed() on the other hand is
233 * suitable for use when a programming mistake has been made.
235 * @param format printf-style format string.
238 _dbus_warn (const char *format,
246 va_start (args, format);
247 vfprintf (stderr, format, args);
258 * Prints a "critical" warning to stderr when an assertion fails;
259 * differs from _dbus_warn primarily in that it prefixes the pid and
260 * defaults to fatal. This should be used only when a programming
261 * error has been detected. (NOT for unavoidable errors that an app
262 * might handle - those should be returned as DBusError.) Calling this
263 * means "there is a bug"
266 _dbus_warn_check_failed(const char *format,
274 fprintf (stderr, "process %lu: ", _dbus_pid_for_log ());
276 va_start (args, format);
277 vfprintf (stderr, format, args);
280 if (fatal_warnings_on_check_failed)
287 #ifdef DBUS_ENABLE_VERBOSE_MODE
289 static dbus_bool_t verbose_initted = FALSE;
290 static dbus_bool_t verbose = TRUE;
292 /** Whether to show the current thread in verbose messages */
293 #define PTHREAD_IN_VERBOSE 0
294 #if PTHREAD_IN_VERBOSE
303 _dbus_verbose_init (void)
305 if (!verbose_initted)
307 const char *p = _dbus_getenv ("DBUS_VERBOSE");
308 verbose = p != NULL && *p == '1';
309 verbose_initted = TRUE;
314 * Implementation of dbus_is_verbose() macro if built with verbose logging
316 * @returns whether verbose logging is active.
319 _dbus_is_verbose_real (void)
321 _dbus_verbose_init ();
326 * Prints a warning message to stderr
327 * if the user has enabled verbose mode.
328 * This is the real function implementation,
329 * use _dbus_verbose() macro in code.
331 * @param format printf-style format string.
334 _dbus_verbose_real (const char *format,
338 static dbus_bool_t need_pid = TRUE;
341 /* things are written a bit oddly here so that
342 * in the non-verbose case we just have the one
343 * conditional and return immediately.
345 if (!_dbus_is_verbose_real())
348 /* Print out pid before the line */
351 #if PTHREAD_IN_VERBOSE
352 fprintf (stderr, "%lu: 0x%lx: ", _dbus_pid_for_log (), pthread_self ());
354 fprintf (stderr, "%lu: ", _dbus_pid_for_log ());
359 /* Only print pid again if the next line is a new line */
360 len = strlen (format);
361 if (format[len-1] == '\n')
366 va_start (args, format);
367 vfprintf (stderr, format, args);
374 * Reinitializes the verbose logging code, used
375 * as a hack in dbus-spawn.c so that a child
376 * process re-reads its pid
380 _dbus_verbose_reset_real (void)
382 verbose_initted = FALSE;
385 #endif /* DBUS_ENABLE_VERBOSE_MODE */
388 * Duplicates a string. Result must be freed with
389 * dbus_free(). Returns #NULL if memory allocation fails.
390 * If the string to be duplicated is #NULL, returns #NULL.
392 * @param str string to duplicate.
393 * @returns newly-allocated copy.
396 _dbus_strdup (const char *str)
406 copy = dbus_malloc (len + 1);
410 memcpy (copy, str, len + 1);
416 * Duplicates a block of memory. Returns
419 * @param mem memory to copy
420 * @param n_bytes number of bytes to copy
424 _dbus_memdup (const void *mem,
429 copy = dbus_malloc (n_bytes);
433 memcpy (copy, mem, n_bytes);
439 * Duplicates a string array. Result may be freed with
440 * dbus_free_string_array(). Returns #NULL if memory allocation fails.
441 * If the array to be duplicated is #NULL, returns #NULL.
443 * @param array array to duplicate.
444 * @returns newly-allocated copy.
447 _dbus_dup_string_array (const char **array)
456 for (len = 0; array[len] != NULL; ++len)
459 copy = dbus_new0 (char*, len + 1);
466 copy[i] = _dbus_strdup (array[i]);
469 dbus_free_string_array (copy);
480 * Checks whether a string array contains the given string.
482 * @param array array to search.
483 * @param str string to look for
484 * @returns #TRUE if array contains string
487 _dbus_string_array_contains (const char **array,
493 while (array[i] != NULL)
495 if (strcmp (array[i], str) == 0)
504 * Generates a new UUID. If you change how this is done,
505 * there's some text about it in the spec that should also change.
507 * @param uuid the uuid to initialize
510 _dbus_generate_uuid (DBusGUID *uuid)
514 _dbus_get_current_time (&now, NULL);
516 uuid->as_uint32s[DBUS_UUID_LENGTH_WORDS - 1] = DBUS_UINT32_TO_BE (now);
518 _dbus_generate_random_bytes_buffer (uuid->as_bytes, DBUS_UUID_LENGTH_BYTES - 4);
524 * @param uuid the uuid
525 * @param encoded string to append hex uuid to
526 * @returns #FALSE if no memory
529 _dbus_uuid_encode (const DBusGUID *uuid,
533 _dbus_string_init_const_len (&binary, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES);
534 return _dbus_string_hex_encode (&binary, 0, encoded, _dbus_string_get_length (encoded));
538 _dbus_read_uuid_file_without_creating (const DBusString *filename,
546 if (!_dbus_string_init (&contents))
548 _DBUS_SET_OOM (error);
552 if (!_dbus_string_init (&decoded))
554 _dbus_string_free (&contents);
555 _DBUS_SET_OOM (error);
559 if (!_dbus_file_get_contents (&contents, filename, error))
562 _dbus_string_chop_white (&contents);
564 if (_dbus_string_get_length (&contents) != DBUS_UUID_LENGTH_HEX)
566 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
567 "UUID file '%s' should contain a hex string of length %d, not length %d, with no other text",
568 _dbus_string_get_const_data (filename),
569 DBUS_UUID_LENGTH_HEX,
570 _dbus_string_get_length (&contents));
574 if (!_dbus_string_hex_decode (&contents, 0, &end, &decoded, 0))
576 _DBUS_SET_OOM (error);
582 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
583 "UUID file '%s' contains invalid hex data",
584 _dbus_string_get_const_data (filename));
588 if (_dbus_string_get_length (&decoded) != DBUS_UUID_LENGTH_BYTES)
590 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
591 "UUID file '%s' contains %d bytes of hex-encoded data instead of %d",
592 _dbus_string_get_const_data (filename),
593 _dbus_string_get_length (&decoded),
594 DBUS_UUID_LENGTH_BYTES);
598 _dbus_string_copy_to_buffer (&decoded, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES);
600 _dbus_string_free (&decoded);
601 _dbus_string_free (&contents);
603 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
608 _DBUS_ASSERT_ERROR_IS_SET (error);
609 _dbus_string_free (&contents);
610 _dbus_string_free (&decoded);
615 _dbus_create_uuid_file_exclusively (const DBusString *filename,
621 if (!_dbus_string_init (&encoded))
623 _DBUS_SET_OOM (error);
627 _dbus_generate_uuid (uuid);
629 if (!_dbus_uuid_encode (uuid, &encoded))
631 _DBUS_SET_OOM (error);
635 /* FIXME this is racy; we need a save_file_exclusively
636 * function. But in practice this should be fine for now.
638 * - first be sure we can create the file and it
639 * doesn't exist by creating it empty with O_EXCL
640 * - then create it by creating a temporary file and
641 * overwriting atomically with rename()
643 if (!_dbus_create_file_exclusively (filename, error))
646 if (!_dbus_string_append_byte (&encoded, '\n'))
648 _DBUS_SET_OOM (error);
652 if (!_dbus_string_save_to_file (&encoded, filename, error))
655 if (!_dbus_make_file_world_readable (filename, error))
658 _dbus_string_free (&encoded);
660 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
664 _DBUS_ASSERT_ERROR_IS_SET (error);
665 _dbus_string_free (&encoded);
670 * Reads (and optionally writes) a uuid to a file. Initializes the uuid
671 * unless an error is returned.
673 * @param filename the name of the file
674 * @param uuid uuid to be initialized with the loaded uuid
675 * @param create_if_not_found #TRUE to create a new uuid and save it if the file doesn't exist
676 * @param error the error return
677 * @returns #FALSE if the error is set
680 _dbus_read_uuid_file (const DBusString *filename,
682 dbus_bool_t create_if_not_found,
685 DBusError read_error = DBUS_ERROR_INIT;
687 if (_dbus_read_uuid_file_without_creating (filename, uuid, &read_error))
690 if (!create_if_not_found)
692 dbus_move_error (&read_error, error);
696 /* If the file exists and contains junk, we want to keep that error
697 * message instead of overwriting it with a "file exists" error
698 * message when we try to write
700 if (dbus_error_has_name (&read_error, DBUS_ERROR_INVALID_FILE_CONTENT))
702 dbus_move_error (&read_error, error);
707 dbus_error_free (&read_error);
708 return _dbus_create_uuid_file_exclusively (filename, uuid, error);
712 _DBUS_DEFINE_GLOBAL_LOCK (machine_uuid);
713 static int machine_uuid_initialized_generation = 0;
714 static DBusGUID machine_uuid;
717 * Gets the hex-encoded UUID of the machine this function is
718 * executed on. This UUID is guaranteed to be the same for a given
719 * machine at least until it next reboots, though it also
720 * makes some effort to be the same forever, it may change if the
721 * machine is reconfigured or its hardware is modified.
723 * @param uuid_str string to append hex-encoded machine uuid to
724 * @returns #FALSE if no memory
727 _dbus_get_local_machine_uuid_encoded (DBusString *uuid_str)
731 _DBUS_LOCK (machine_uuid);
732 if (machine_uuid_initialized_generation != _dbus_current_generation)
734 DBusError error = DBUS_ERROR_INIT;
736 if (!_dbus_read_local_machine_uuid (&machine_uuid, FALSE,
739 #ifndef DBUS_BUILD_TESTS
740 /* For the test suite, we may not be installed so just continue silently
741 * here. But in a production build, we want to be nice and loud about
744 _dbus_warn_check_failed ("D-Bus library appears to be incorrectly set up; failed to read machine uuid: %s\n"
745 "See the manual page for dbus-uuidgen to correct this issue.\n",
749 dbus_error_free (&error);
751 _dbus_generate_uuid (&machine_uuid);
755 ok = _dbus_uuid_encode (&machine_uuid, uuid_str);
757 _DBUS_UNLOCK (machine_uuid);
762 #ifdef DBUS_BUILD_TESTS
764 * Returns a string describing the given name.
766 * @param header_field the field to describe
767 * @returns a constant string describing the field
770 _dbus_header_field_to_string (int header_field)
772 switch (header_field)
774 case DBUS_HEADER_FIELD_INVALID:
776 case DBUS_HEADER_FIELD_PATH:
778 case DBUS_HEADER_FIELD_INTERFACE:
780 case DBUS_HEADER_FIELD_MEMBER:
782 case DBUS_HEADER_FIELD_ERROR_NAME:
784 case DBUS_HEADER_FIELD_REPLY_SERIAL:
785 return "reply-serial";
786 case DBUS_HEADER_FIELD_DESTINATION:
787 return "destination";
788 case DBUS_HEADER_FIELD_SENDER:
790 case DBUS_HEADER_FIELD_SIGNATURE:
796 #endif /* DBUS_BUILD_TESTS */
798 #ifndef DBUS_DISABLE_CHECKS
799 /** String used in _dbus_return_if_fail macro */
800 const char _dbus_return_if_fail_warning_format[] =
801 "arguments to %s() were incorrect, assertion \"%s\" failed in file %s line %d.\n"
802 "This is normally a bug in some application using the D-Bus library.\n";
805 #ifndef DBUS_DISABLE_ASSERT
807 * Internals of _dbus_assert(); it's a function
808 * rather than a macro with the inline code so
809 * that the assertion failure blocks don't show up
810 * in test suite coverage, and to shrink code size.
812 * @param condition TRUE if assertion succeeded
813 * @param condition_text condition as a string
814 * @param file file the assertion is in
815 * @param line line the assertion is in
816 * @param func function the assertion is in
819 _dbus_real_assert (dbus_bool_t condition,
820 const char *condition_text,
825 if (_DBUS_UNLIKELY (!condition))
827 _dbus_warn ("%lu: assertion failed \"%s\" file \"%s\" line %d function %s\n",
828 _dbus_pid_for_log (), condition_text, file, line, func);
834 * Internals of _dbus_assert_not_reached(); it's a function
835 * rather than a macro with the inline code so
836 * that the assertion failure blocks don't show up
837 * in test suite coverage, and to shrink code size.
839 * @param explanation what was reached that shouldn't have been
840 * @param file file the assertion is in
841 * @param line line the assertion is in
844 _dbus_real_assert_not_reached (const char *explanation,
848 _dbus_warn ("File \"%s\" line %d process %lu should not have been reached: %s\n",
849 file, line, _dbus_pid_for_log (), explanation);
852 #endif /* DBUS_DISABLE_ASSERT */
854 #ifdef DBUS_BUILD_TESTS
856 run_failing_each_malloc (int n_mallocs,
857 const char *description,
858 DBusTestMemoryFunction func,
861 n_mallocs += 10; /* fudge factor to ensure reallocs etc. are covered */
863 while (n_mallocs >= 0)
865 _dbus_set_fail_alloc_counter (n_mallocs);
867 _dbus_verbose ("\n===\n%s: (will fail malloc %d with %d failures)\n===\n",
868 description, n_mallocs,
869 _dbus_get_fail_alloc_failures ());
871 if (!(* func) (data))
877 _dbus_set_fail_alloc_counter (_DBUS_INT_MAX);
883 * Tests how well the given function responds to out-of-memory
884 * situations. Calls the function repeatedly, failing a different
885 * call to malloc() each time. If the function ever returns #FALSE,
886 * the test fails. The function should return #TRUE whenever something
887 * valid (such as returning an error, or succeeding) occurs, and #FALSE
888 * if it gets confused in some way.
890 * @param description description of the test used in verbose output
891 * @param func function to call
892 * @param data data to pass to function
893 * @returns #TRUE if the function never returns FALSE
896 _dbus_test_oom_handling (const char *description,
897 DBusTestMemoryFunction func,
902 int max_failures_to_try;
905 /* Run once to see about how many mallocs are involved */
907 _dbus_set_fail_alloc_counter (_DBUS_INT_MAX);
909 _dbus_verbose ("Running once to count mallocs\n");
911 if (!(* func) (data))
914 approx_mallocs = _DBUS_INT_MAX - _dbus_get_fail_alloc_counter ();
916 _dbus_verbose ("\n=================\n%s: about %d mallocs total\n=================\n",
917 description, approx_mallocs);
919 setting = _dbus_getenv ("DBUS_TEST_MALLOC_FAILURES");
924 _dbus_string_init_const (&str, setting);
926 if (!_dbus_string_parse_int (&str, 0, &v, NULL))
927 _dbus_warn ("couldn't parse '%s' as integer\n", setting);
928 max_failures_to_try = v;
932 max_failures_to_try = 4;
935 i = setting ? max_failures_to_try - 1 : 1;
936 while (i < max_failures_to_try)
938 _dbus_set_fail_alloc_failures (i);
939 if (!run_failing_each_malloc (approx_mallocs, description, func, data))
944 _dbus_verbose ("\n=================\n%s: all iterations passed\n=================\n",
949 #endif /* DBUS_BUILD_TESTS */