1 /* -*- mode: C; c-file-style: "gnu" -*- */
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-test.h"
32 * @defgroup DBusInternals D-Bus secret internal implementation details
33 * @brief Documentation useful when developing or debugging D-Bus itself.
38 * @defgroup DBusInternalsUtils Utilities and portability
39 * @ingroup DBusInternals
40 * @brief Utility functions (_dbus_assert(), _dbus_warn(), etc.)
47 * Aborts with an error message if the condition is false.
49 * @param condition condition which must be true.
53 * @def _dbus_assert_not_reached
55 * Aborts with an error message if called.
56 * The given explanation will be printed.
58 * @param explanation explanation of what happened if the code was reached.
62 * @def _DBUS_N_ELEMENTS
64 * Computes the number of elements in a fixed-size array using
67 * @param array the array to count elements in.
71 * @def _DBUS_POINTER_TO_INT
73 * Safely casts a void* to an integer; should only be used on void*
74 * that actually contain integers, for example one created with
75 * _DBUS_INT_TO_POINTER. Only guaranteed to preserve 32 bits.
76 * (i.e. it's used to store 32-bit ints in pointers, but
77 * can't be used to store 64-bit pointers in ints.)
79 * @param pointer pointer to extract an integer from.
82 * @def _DBUS_INT_TO_POINTER
84 * Safely stuffs an integer into a pointer, to be extracted later with
85 * _DBUS_POINTER_TO_INT. Only guaranteed to preserve 32 bits.
87 * @param integer the integer to stuff into a pointer.
92 * Sets all bits in an object to zero.
94 * @param object the object to be zeroed.
97 * @def _DBUS_INT16_MIN
99 * Minimum value of type "int16"
102 * @def _DBUS_INT16_MAX
104 * Maximum value of type "int16"
107 * @def _DBUS_UINT16_MAX
109 * Maximum value of type "uint16"
113 * @def _DBUS_INT32_MIN
115 * Minimum value of type "int32"
118 * @def _DBUS_INT32_MAX
120 * Maximum value of type "int32"
123 * @def _DBUS_UINT32_MAX
125 * Maximum value of type "uint32"
131 * Minimum value of type "int"
136 * Maximum value of type "int"
139 * @def _DBUS_UINT_MAX
141 * Maximum value of type "uint"
145 * @typedef DBusForeachFunction
147 * Used to iterate over each item in a collection, such as
152 * @def _DBUS_LOCK_NAME
154 * Expands to name of a global lock variable.
158 * @def _DBUS_DEFINE_GLOBAL_LOCK
160 * Defines a global lock variable with the given name.
161 * The lock must be added to the list to initialize
162 * in dbus_threads_init().
166 * @def _DBUS_DECLARE_GLOBAL_LOCK
168 * Expands to declaration of a global lock defined
169 * with _DBUS_DEFINE_GLOBAL_LOCK.
170 * The lock must be added to the list to initialize
171 * in dbus_threads_init().
177 * Locks a global lock
183 * Unlocks a global lock
187 * Fixed "out of memory" error message, just to avoid
188 * making up a different string every time and wasting
191 const char _dbus_no_memory_message[] = "Not enough memory";
193 static dbus_bool_t warn_initted = FALSE;
194 static dbus_bool_t fatal_warnings = FALSE;
195 static dbus_bool_t fatal_warnings_on_check_failed = TRUE;
203 s = _dbus_getenv ("DBUS_FATAL_WARNINGS");
208 fatal_warnings = FALSE;
209 fatal_warnings_on_check_failed = FALSE;
213 fatal_warnings = TRUE;
214 fatal_warnings_on_check_failed = TRUE;
218 fprintf(stderr, "DBUS_FATAL_WARNINGS should be set to 0 or 1 if set, not '%s'",
228 * Prints a warning message to stderr. Can optionally be made to exit
229 * fatally by setting DBUS_FATAL_WARNINGS, but this is rarely
230 * used. This function should be considered pretty much equivalent to
231 * fprintf(stderr). _dbus_warn_check_failed() on the other hand is
232 * suitable for use when a programming mistake has been made.
234 * @param format printf-style format string.
237 _dbus_warn (const char *format,
245 va_start (args, format);
246 vfprintf (stderr, format, args);
257 * Prints a "critical" warning to stderr when an assertion fails;
258 * differs from _dbus_warn primarily in that it prefixes the pid and
259 * defaults to fatal. This should be used only when a programming
260 * error has been detected. (NOT for unavoidable errors that an app
261 * might handle - those should be returned as DBusError.) Calling this
262 * means "there is a bug"
265 _dbus_warn_check_failed(const char *format,
273 fprintf (stderr, "process %lu: ", _dbus_getpid ());
275 va_start (args, format);
276 vfprintf (stderr, format, args);
279 if (fatal_warnings_on_check_failed)
286 #ifdef DBUS_ENABLE_VERBOSE_MODE
288 static dbus_bool_t verbose_initted = FALSE;
289 static dbus_bool_t verbose = TRUE;
291 /** Whether to show the current thread in verbose messages */
292 #define PTHREAD_IN_VERBOSE 0
293 #if PTHREAD_IN_VERBOSE
298 _dbus_verbose_init (void)
300 if (!verbose_initted)
302 const char *p = _dbus_getenv ("DBUS_VERBOSE");
303 verbose = p != NULL && *p == '1';
304 verbose_initted = TRUE;
309 * Implementation of dbus_is_verbose() macro if built with verbose logging
311 * @returns whether verbose logging is active.
314 _dbus_is_verbose_real (void)
316 _dbus_verbose_init ();
321 * Prints a warning message to stderr
322 * if the user has enabled verbose mode.
323 * This is the real function implementation,
324 * use _dbus_verbose() macro in code.
326 * @param format printf-style format string.
329 _dbus_verbose_real (const char *format,
333 static dbus_bool_t need_pid = TRUE;
336 /* things are written a bit oddly here so that
337 * in the non-verbose case we just have the one
338 * conditional and return immediately.
340 if (!_dbus_is_verbose_real())
343 /* Print out pid before the line */
346 #if PTHREAD_IN_VERBOSE
347 fprintf (stderr, "%lu: 0x%lx: ", _dbus_getpid (), pthread_self ());
349 fprintf (stderr, "%lu: ", _dbus_getpid ());
354 /* Only print pid again if the next line is a new line */
355 len = strlen (format);
356 if (format[len-1] == '\n')
361 va_start (args, format);
362 vfprintf (stderr, format, args);
369 * Reinitializes the verbose logging code, used
370 * as a hack in dbus-spawn.c so that a child
371 * process re-reads its pid
375 _dbus_verbose_reset_real (void)
377 verbose_initted = FALSE;
380 #endif /* DBUS_ENABLE_VERBOSE_MODE */
383 * Duplicates a string. Result must be freed with
384 * dbus_free(). Returns #NULL if memory allocation fails.
385 * If the string to be duplicated is #NULL, returns #NULL.
387 * @param str string to duplicate.
388 * @returns newly-allocated copy.
391 _dbus_strdup (const char *str)
401 copy = dbus_malloc (len + 1);
405 memcpy (copy, str, len + 1);
411 * Duplicates a block of memory. Returns
414 * @param mem memory to copy
415 * @param n_bytes number of bytes to copy
419 _dbus_memdup (const void *mem,
424 copy = dbus_malloc (n_bytes);
428 memcpy (copy, mem, n_bytes);
434 * Duplicates a string array. Result may be freed with
435 * dbus_free_string_array(). Returns #NULL if memory allocation fails.
436 * If the array to be duplicated is #NULL, returns #NULL.
438 * @param array array to duplicate.
439 * @returns newly-allocated copy.
442 _dbus_dup_string_array (const char **array)
451 for (len = 0; array[len] != NULL; ++len)
454 copy = dbus_new0 (char*, len + 1);
461 copy[i] = _dbus_strdup (array[i]);
464 dbus_free_string_array (copy);
475 * Checks whether a string array contains the given string.
477 * @param array array to search.
478 * @param str string to look for
479 * @returns #TRUE if array contains string
482 _dbus_string_array_contains (const char **array,
488 while (array[i] != NULL)
490 if (strcmp (array[i], str) == 0)
499 * Generates a new UUID. If you change how this is done,
500 * there's some text about it in the spec that should also change.
502 * @param uuid the uuid to initialize
505 _dbus_generate_uuid (DBusGUID *uuid)
511 _dbus_get_current_time (&now, NULL);
513 uuid->as_uint32s[0] = now;
515 ts_size = sizeof (uuid->as_uint32s[0]);
516 p = ((char*)uuid->as_bytes) + ts_size;
518 _dbus_generate_random_bytes_buffer (p,
519 sizeof (uuid->as_bytes) - ts_size);
525 * @param uuid the uuid
526 * @param encoded string to append hex uuid to
527 * @returns #FALSE if no memory
530 _dbus_uuid_encode (const DBusGUID *uuid,
534 _dbus_string_init_const_len (&binary, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES);
535 return _dbus_string_hex_encode (&binary, 0, encoded, _dbus_string_get_length (encoded));
539 _dbus_read_uuid_file_without_creating (const DBusString *filename,
547 _dbus_string_init (&contents);
548 _dbus_string_init (&decoded);
550 if (!_dbus_file_get_contents (&contents, filename, error))
553 _dbus_string_chop_white (&contents);
555 if (_dbus_string_get_length (&contents) != DBUS_UUID_LENGTH_HEX)
557 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
558 "UUID file '%s' should contain a hex string of length %d, not length %d, with no other text",
559 _dbus_string_get_const_data (filename),
560 DBUS_UUID_LENGTH_HEX,
561 _dbus_string_get_length (&contents));
565 if (!_dbus_string_hex_decode (&contents, 0, &end, &decoded, 0))
567 _DBUS_SET_OOM (error);
573 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
574 "UUID file '%s' contains invalid hex data",
575 _dbus_string_get_const_data (filename));
579 if (_dbus_string_get_length (&decoded) != DBUS_UUID_LENGTH_BYTES)
581 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
582 "UUID file '%s' contains %d bytes of hex-encoded data instead of %d",
583 _dbus_string_get_const_data (filename),
584 _dbus_string_get_length (&decoded),
585 DBUS_UUID_LENGTH_BYTES);
589 _dbus_string_copy_to_buffer (&decoded, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES);
591 _dbus_string_free (&decoded);
592 _dbus_string_free (&contents);
594 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
599 _DBUS_ASSERT_ERROR_IS_SET (error);
600 _dbus_string_free (&contents);
601 _dbus_string_free (&decoded);
606 _dbus_create_uuid_file_exclusively (const DBusString *filename,
612 _dbus_string_init (&encoded);
614 _dbus_generate_uuid (uuid);
616 if (!_dbus_uuid_encode (uuid, &encoded))
618 _DBUS_SET_OOM (error);
622 /* FIXME this is racy; we need a save_file_exclusively
623 * function. But in practice this should be fine for now.
625 * - first be sure we can create the file and it
626 * doesn't exist by creating it empty with O_EXCL
627 * - then create it by creating a temporary file and
628 * overwriting atomically with rename()
630 if (!_dbus_create_file_exclusively (filename, error))
633 if (!_dbus_string_append_byte (&encoded, '\n'))
635 _DBUS_SET_OOM (error);
639 if (!_dbus_string_save_to_file (&encoded, filename, error))
643 _dbus_string_free (&encoded);
645 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
649 _DBUS_ASSERT_ERROR_IS_SET (error);
650 _dbus_string_free (&encoded);
655 * Reads (and optionally writes) a uuid to a file. Initializes the uuid
656 * unless an error is returned.
658 * @param filename the name of the file
659 * @param uuid uuid to be initialized with the loaded uuid
660 * @param create_if_not_found #TRUE to create a new uuid and save it if the file doesn't exist
661 * @param error the error return
662 * @returns #FALSE if the error is set
665 _dbus_read_uuid_file (const DBusString *filename,
667 dbus_bool_t create_if_not_found,
670 DBusError read_error;
672 dbus_error_init (&read_error);
674 if (_dbus_read_uuid_file_without_creating (filename, uuid, &read_error))
677 if (!create_if_not_found)
679 dbus_move_error (&read_error, error);
683 /* If the file exists and contains junk, we want to keep that error
684 * message instead of overwriting it with a "file exists" error
685 * message when we try to write
687 if (dbus_error_has_name (&read_error, DBUS_ERROR_INVALID_FILE_CONTENT))
689 dbus_move_error (&read_error, error);
694 dbus_error_free (&read_error);
695 return _dbus_create_uuid_file_exclusively (filename, uuid, error);
699 _DBUS_DEFINE_GLOBAL_LOCK (machine_uuid);
700 static int machine_uuid_initialized_generation = 0;
701 static DBusGUID machine_uuid;
704 * Gets the hex-encoded UUID of the machine this function is
705 * executed on. This UUID is guaranteed to be the same for a given
706 * machine at least until it next reboots, though it also
707 * makes some effort to be the same forever, it may change if the
708 * machine is reconfigured or its hardware is modified.
710 * @param uuid_str string to append hex-encoded machine uuid to
711 * @returns #FALSE if no memory
714 _dbus_get_local_machine_uuid_encoded (DBusString *uuid_str)
718 _DBUS_LOCK (machine_uuid);
719 if (machine_uuid_initialized_generation != _dbus_current_generation)
722 dbus_error_init (&error);
723 if (!_dbus_read_local_machine_uuid (&machine_uuid, FALSE,
726 #ifndef DBUS_BUILD_TESTS
727 /* For the test suite, we may not be installed so just continue silently
728 * here. But in a production build, we want to be nice and loud about
731 _dbus_warn_check_failed ("D-Bus library appears to be incorrectly set up; failed to read machine uuid: %s\n"
732 "See the manual page for dbus-uuidgen to correct this issue.\n",
736 dbus_error_free (&error);
738 _dbus_generate_uuid (&machine_uuid);
742 ok = _dbus_uuid_encode (&machine_uuid, uuid_str);
744 _DBUS_UNLOCK (machine_uuid);
749 #ifdef DBUS_BUILD_TESTS
751 * Returns a string describing the given name.
753 * @param header_field the field to describe
754 * @returns a constant string describing the field
757 _dbus_header_field_to_string (int header_field)
759 switch (header_field)
761 case DBUS_HEADER_FIELD_INVALID:
763 case DBUS_HEADER_FIELD_PATH:
765 case DBUS_HEADER_FIELD_INTERFACE:
767 case DBUS_HEADER_FIELD_MEMBER:
769 case DBUS_HEADER_FIELD_ERROR_NAME:
771 case DBUS_HEADER_FIELD_REPLY_SERIAL:
772 return "reply-serial";
773 case DBUS_HEADER_FIELD_DESTINATION:
774 return "destination";
775 case DBUS_HEADER_FIELD_SENDER:
777 case DBUS_HEADER_FIELD_SIGNATURE:
783 #endif /* DBUS_BUILD_TESTS */
785 #ifndef DBUS_DISABLE_CHECKS
786 /** String used in _dbus_return_if_fail macro */
787 const char _dbus_return_if_fail_warning_format[] =
788 "arguments to %s() were incorrect, assertion \"%s\" failed in file %s line %d.\n"
789 "This is normally a bug in some application using the D-Bus library.\n";
792 #ifndef DBUS_DISABLE_ASSERT
794 * Internals of _dbus_assert(); it's a function
795 * rather than a macro with the inline code so
796 * that the assertion failure blocks don't show up
797 * in test suite coverage, and to shrink code size.
799 * @param condition TRUE if assertion succeeded
800 * @param condition_text condition as a string
801 * @param file file the assertion is in
802 * @param line line the assertion is in
803 * @param func function the assertion is in
806 _dbus_real_assert (dbus_bool_t condition,
807 const char *condition_text,
812 if (_DBUS_UNLIKELY (!condition))
814 _dbus_warn ("%lu: assertion failed \"%s\" file \"%s\" line %d function %s\n",
815 _dbus_getpid (), condition_text, file, line, func);
821 * Internals of _dbus_assert_not_reached(); it's a function
822 * rather than a macro with the inline code so
823 * that the assertion failure blocks don't show up
824 * in test suite coverage, and to shrink code size.
826 * @param explanation what was reached that shouldn't have been
827 * @param file file the assertion is in
828 * @param line line the assertion is in
831 _dbus_real_assert_not_reached (const char *explanation,
835 _dbus_warn ("File \"%s\" line %d process %lu should not have been reached: %s\n",
836 file, line, _dbus_getpid (), explanation);
839 #endif /* DBUS_DISABLE_ASSERT */
841 #ifdef DBUS_BUILD_TESTS
843 run_failing_each_malloc (int n_mallocs,
844 const char *description,
845 DBusTestMemoryFunction func,
848 n_mallocs += 10; /* fudge factor to ensure reallocs etc. are covered */
850 while (n_mallocs >= 0)
852 _dbus_set_fail_alloc_counter (n_mallocs);
854 _dbus_verbose ("\n===\n%s: (will fail malloc %d with %d failures)\n===\n",
855 description, n_mallocs,
856 _dbus_get_fail_alloc_failures ());
858 if (!(* func) (data))
864 _dbus_set_fail_alloc_counter (_DBUS_INT_MAX);
870 * Tests how well the given function responds to out-of-memory
871 * situations. Calls the function repeatedly, failing a different
872 * call to malloc() each time. If the function ever returns #FALSE,
873 * the test fails. The function should return #TRUE whenever something
874 * valid (such as returning an error, or succeeding) occurs, and #FALSE
875 * if it gets confused in some way.
877 * @param description description of the test used in verbose output
878 * @param func function to call
879 * @param data data to pass to function
880 * @returns #TRUE if the function never returns FALSE
883 _dbus_test_oom_handling (const char *description,
884 DBusTestMemoryFunction func,
889 int max_failures_to_try;
892 /* Run once to see about how many mallocs are involved */
894 _dbus_set_fail_alloc_counter (_DBUS_INT_MAX);
896 _dbus_verbose ("Running once to count mallocs\n");
898 if (!(* func) (data))
901 approx_mallocs = _DBUS_INT_MAX - _dbus_get_fail_alloc_counter ();
903 _dbus_verbose ("\n=================\n%s: about %d mallocs total\n=================\n",
904 description, approx_mallocs);
906 setting = _dbus_getenv ("DBUS_TEST_MALLOC_FAILURES");
911 _dbus_string_init_const (&str, setting);
913 if (!_dbus_string_parse_int (&str, 0, &v, NULL))
914 _dbus_warn ("couldn't parse '%s' as integer\n", setting);
915 max_failures_to_try = v;
919 max_failures_to_try = 4;
922 i = setting ? max_failures_to_try - 1 : 1;
923 while (i < max_failures_to_try)
925 _dbus_set_fail_alloc_failures (i);
926 if (!run_failing_each_malloc (approx_mallocs, description, func, data))
931 _dbus_verbose ("\n=================\n%s: all iterations passed\n=================\n",
936 #endif /* DBUS_BUILD_TESTS */