/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ /* dbus-internals.c random utility stuff (internal to D-Bus implementation) * * Copyright (C) 2002, 2003 Red Hat, Inc. * * Licensed under the Academic Free License version 2.1 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * */ #include "dbus-internals.h" #include "dbus-protocol.h" #include "dbus-marshal-basic.h" #include "dbus-test.h" #include #include #include #include /** * @defgroup DBusInternals D-Bus secret internal implementation details * @brief Documentation useful when developing or debugging D-Bus itself. * */ /** * @defgroup DBusInternalsUtils Utilities and portability * @ingroup DBusInternals * @brief Utility functions (_dbus_assert(), _dbus_warn(), etc.) * @{ */ /** * @def _dbus_assert * * Aborts with an error message if the condition is false. * * @param condition condition which must be true. */ /** * @def _dbus_assert_not_reached * * Aborts with an error message if called. * The given explanation will be printed. * * @param explanation explanation of what happened if the code was reached. */ /** * @def _DBUS_N_ELEMENTS * * Computes the number of elements in a fixed-size array using * sizeof(). * * @param array the array to count elements in. */ /** * @def _DBUS_POINTER_TO_INT * * Safely casts a void* to an integer; should only be used on void* * that actually contain integers, for example one created with * _DBUS_INT_TO_POINTER. Only guaranteed to preserve 32 bits. * (i.e. it's used to store 32-bit ints in pointers, but * can't be used to store 64-bit pointers in ints.) * * @param pointer pointer to extract an integer from. */ /** * @def _DBUS_INT_TO_POINTER * * Safely stuffs an integer into a pointer, to be extracted later with * _DBUS_POINTER_TO_INT. Only guaranteed to preserve 32 bits. * * @param integer the integer to stuff into a pointer. */ /** * @def _DBUS_ZERO * * Sets all bits in an object to zero. * * @param object the object to be zeroed. */ /** * @def _DBUS_INT16_MIN * * Minimum value of type "int16" */ /** * @def _DBUS_INT16_MAX * * Maximum value of type "int16" */ /** * @def _DBUS_UINT16_MAX * * Maximum value of type "uint16" */ /** * @def _DBUS_INT32_MIN * * Minimum value of type "int32" */ /** * @def _DBUS_INT32_MAX * * Maximum value of type "int32" */ /** * @def _DBUS_UINT32_MAX * * Maximum value of type "uint32" */ /** * @def _DBUS_INT_MIN * * Minimum value of type "int" */ /** * @def _DBUS_INT_MAX * * Maximum value of type "int" */ /** * @def _DBUS_UINT_MAX * * Maximum value of type "uint" */ /** * @typedef DBusForeachFunction * * Used to iterate over each item in a collection, such as * a DBusList. */ /** * @def _DBUS_LOCK_NAME * * Expands to name of a global lock variable. */ /** * @def _DBUS_DEFINE_GLOBAL_LOCK * * Defines a global lock variable with the given name. * The lock must be added to the list to initialize * in dbus_threads_init(). */ /** * @def _DBUS_DECLARE_GLOBAL_LOCK * * Expands to declaration of a global lock defined * with _DBUS_DEFINE_GLOBAL_LOCK. * The lock must be added to the list to initialize * in dbus_threads_init(). */ /** * @def _DBUS_LOCK * * Locks a global lock */ /** * @def _DBUS_UNLOCK * * Unlocks a global lock */ /** * Fixed "out of memory" error message, just to avoid * making up a different string every time and wasting * space. */ const char _dbus_no_memory_message[] = "Not enough memory"; static dbus_bool_t warn_initted = FALSE; static dbus_bool_t fatal_warnings = FALSE; static dbus_bool_t fatal_warnings_on_check_failed = TRUE; static void init_warnings(void) { if (!warn_initted) { const char *s; s = _dbus_getenv ("DBUS_FATAL_WARNINGS"); if (s && *s) { if (*s == '0') { fatal_warnings = FALSE; fatal_warnings_on_check_failed = FALSE; } else if (*s == '1') { fatal_warnings = TRUE; fatal_warnings_on_check_failed = TRUE; } else { fprintf(stderr, "DBUS_FATAL_WARNINGS should be set to 0 or 1 if set, not '%s'", s); } } warn_initted = TRUE; } } /** * Prints a warning message to stderr. Can optionally be made to exit * fatally by setting DBUS_FATAL_WARNINGS, but this is rarely * used. This function should be considered pretty much equivalent to * fprintf(stderr). _dbus_warn_check_failed() on the other hand is * suitable for use when a programming mistake has been made. * * @param format printf-style format string. */ void _dbus_warn (const char *format, ...) { va_list args; if (!warn_initted) init_warnings (); va_start (args, format); vfprintf (stderr, format, args); va_end (args); if (fatal_warnings) { fflush (stderr); _dbus_abort (); } } /** * Prints a "critical" warning to stderr when an assertion fails; * differs from _dbus_warn primarily in that it prefixes the pid and * defaults to fatal. This should be used only when a programming * error has been detected. (NOT for unavoidable errors that an app * might handle - those should be returned as DBusError.) Calling this * means "there is a bug" */ void _dbus_warn_check_failed(const char *format, ...) { va_list args; if (!warn_initted) init_warnings (); fprintf (stderr, "process %lu: ", _dbus_pid_for_log ()); va_start (args, format); vfprintf (stderr, format, args); va_end (args); if (fatal_warnings_on_check_failed) { fflush (stderr); _dbus_abort (); } } #ifdef DBUS_ENABLE_VERBOSE_MODE static dbus_bool_t verbose_initted = FALSE; static dbus_bool_t verbose = TRUE; /** Whether to show the current thread in verbose messages */ #define PTHREAD_IN_VERBOSE 0 #if PTHREAD_IN_VERBOSE #include #endif #ifdef DBUS_WIN #define inline #endif static inline void _dbus_verbose_init (void) { if (!verbose_initted) { const char *p = _dbus_getenv ("DBUS_VERBOSE"); verbose = p != NULL && *p == '1'; verbose_initted = TRUE; } } /** * Implementation of dbus_is_verbose() macro if built with verbose logging * enabled. * @returns whether verbose logging is active. */ dbus_bool_t _dbus_is_verbose_real (void) { _dbus_verbose_init (); return verbose; } /** * Prints a warning message to stderr * if the user has enabled verbose mode. * This is the real function implementation, * use _dbus_verbose() macro in code. * * @param format printf-style format string. */ void _dbus_verbose_real (const char *format, ...) { va_list args; static dbus_bool_t need_pid = TRUE; int len; /* things are written a bit oddly here so that * in the non-verbose case we just have the one * conditional and return immediately. */ if (!_dbus_is_verbose_real()) return; /* Print out pid before the line */ if (need_pid) { #if PTHREAD_IN_VERBOSE fprintf (stderr, "%lu: 0x%lx: ", _dbus_pid_for_log (), pthread_self ()); #else fprintf (stderr, "%lu: ", _dbus_pid_for_log ()); #endif } /* Only print pid again if the next line is a new line */ len = strlen (format); if (format[len-1] == '\n') need_pid = TRUE; else need_pid = FALSE; va_start (args, format); vfprintf (stderr, format, args); va_end (args); fflush (stderr); } /** * Reinitializes the verbose logging code, used * as a hack in dbus-spawn.c so that a child * process re-reads its pid * */ void _dbus_verbose_reset_real (void) { verbose_initted = FALSE; } #endif /* DBUS_ENABLE_VERBOSE_MODE */ /** * Duplicates a string. Result must be freed with * dbus_free(). Returns #NULL if memory allocation fails. * If the string to be duplicated is #NULL, returns #NULL. * * @param str string to duplicate. * @returns newly-allocated copy. */ char* _dbus_strdup (const char *str) { size_t len; char *copy; if (str == NULL) return NULL; len = strlen (str); copy = dbus_malloc (len + 1); if (copy == NULL) return NULL; memcpy (copy, str, len + 1); return copy; } /** * Duplicates a block of memory. Returns * #NULL on failure. * * @param mem memory to copy * @param n_bytes number of bytes to copy * @returns the copy */ void* _dbus_memdup (const void *mem, size_t n_bytes) { void *copy; copy = dbus_malloc (n_bytes); if (copy == NULL) return NULL; memcpy (copy, mem, n_bytes); return copy; } /** * Duplicates a string array. Result may be freed with * dbus_free_string_array(). Returns #NULL if memory allocation fails. * If the array to be duplicated is #NULL, returns #NULL. * * @param array array to duplicate. * @returns newly-allocated copy. */ char** _dbus_dup_string_array (const char **array) { int len; int i; char **copy; if (array == NULL) return NULL; for (len = 0; array[len] != NULL; ++len) ; copy = dbus_new0 (char*, len + 1); if (copy == NULL) return NULL; i = 0; while (i < len) { copy[i] = _dbus_strdup (array[i]); if (copy[i] == NULL) { dbus_free_string_array (copy); return NULL; } ++i; } return copy; } /** * Checks whether a string array contains the given string. * * @param array array to search. * @param str string to look for * @returns #TRUE if array contains string */ dbus_bool_t _dbus_string_array_contains (const char **array, const char *str) { int i; i = 0; while (array[i] != NULL) { if (strcmp (array[i], str) == 0) return TRUE; ++i; } return FALSE; } /** * Generates a new UUID. If you change how this is done, * there's some text about it in the spec that should also change. * * @param uuid the uuid to initialize */ void _dbus_generate_uuid (DBusGUID *uuid) { long now; _dbus_get_current_time (&now, NULL); uuid->as_uint32s[DBUS_UUID_LENGTH_WORDS - 1] = DBUS_UINT32_TO_BE (now); _dbus_generate_random_bytes_buffer (uuid->as_bytes, DBUS_UUID_LENGTH_BYTES - 4); } /** * Hex-encode a UUID. * * @param uuid the uuid * @param encoded string to append hex uuid to * @returns #FALSE if no memory */ dbus_bool_t _dbus_uuid_encode (const DBusGUID *uuid, DBusString *encoded) { DBusString binary; _dbus_string_init_const_len (&binary, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES); return _dbus_string_hex_encode (&binary, 0, encoded, _dbus_string_get_length (encoded)); } static dbus_bool_t _dbus_read_uuid_file_without_creating (const DBusString *filename, DBusGUID *uuid, DBusError *error) { DBusString contents; DBusString decoded; int end; if (!_dbus_string_init (&contents)) { _DBUS_SET_OOM (error); return FALSE; } if (!_dbus_string_init (&decoded)) { _dbus_string_free (&contents); _DBUS_SET_OOM (error); return FALSE; } if (!_dbus_file_get_contents (&contents, filename, error)) goto error; _dbus_string_chop_white (&contents); if (_dbus_string_get_length (&contents) != DBUS_UUID_LENGTH_HEX) { dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT, "UUID file '%s' should contain a hex string of length %d, not length %d, with no other text", _dbus_string_get_const_data (filename), DBUS_UUID_LENGTH_HEX, _dbus_string_get_length (&contents)); goto error; } if (!_dbus_string_hex_decode (&contents, 0, &end, &decoded, 0)) { _DBUS_SET_OOM (error); goto error; } if (end == 0) { dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT, "UUID file '%s' contains invalid hex data", _dbus_string_get_const_data (filename)); goto error; } if (_dbus_string_get_length (&decoded) != DBUS_UUID_LENGTH_BYTES) { dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT, "UUID file '%s' contains %d bytes of hex-encoded data instead of %d", _dbus_string_get_const_data (filename), _dbus_string_get_length (&decoded), DBUS_UUID_LENGTH_BYTES); goto error; } _dbus_string_copy_to_buffer (&decoded, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES); _dbus_string_free (&decoded); _dbus_string_free (&contents); _DBUS_ASSERT_ERROR_IS_CLEAR (error); return TRUE; error: _DBUS_ASSERT_ERROR_IS_SET (error); _dbus_string_free (&contents); _dbus_string_free (&decoded); return FALSE; } static dbus_bool_t _dbus_create_uuid_file_exclusively (const DBusString *filename, DBusGUID *uuid, DBusError *error) { DBusString encoded; if (!_dbus_string_init (&encoded)) { _DBUS_SET_OOM (error); return FALSE; } _dbus_generate_uuid (uuid); if (!_dbus_uuid_encode (uuid, &encoded)) { _DBUS_SET_OOM (error); goto error; } /* FIXME this is racy; we need a save_file_exclusively * function. But in practice this should be fine for now. * * - first be sure we can create the file and it * doesn't exist by creating it empty with O_EXCL * - then create it by creating a temporary file and * overwriting atomically with rename() */ if (!_dbus_create_file_exclusively (filename, error)) goto error; if (!_dbus_string_append_byte (&encoded, '\n')) { _DBUS_SET_OOM (error); goto error; } if (!_dbus_string_save_to_file (&encoded, filename, error)) goto error; if (!_dbus_make_file_world_readable (filename, error)) goto error; _dbus_string_free (&encoded); _DBUS_ASSERT_ERROR_IS_CLEAR (error); return TRUE; error: _DBUS_ASSERT_ERROR_IS_SET (error); _dbus_string_free (&encoded); return FALSE; } /** * Reads (and optionally writes) a uuid to a file. Initializes the uuid * unless an error is returned. * * @param filename the name of the file * @param uuid uuid to be initialized with the loaded uuid * @param create_if_not_found #TRUE to create a new uuid and save it if the file doesn't exist * @param error the error return * @returns #FALSE if the error is set */ dbus_bool_t _dbus_read_uuid_file (const DBusString *filename, DBusGUID *uuid, dbus_bool_t create_if_not_found, DBusError *error) { DBusError read_error = DBUS_ERROR_INIT; if (_dbus_read_uuid_file_without_creating (filename, uuid, &read_error)) return TRUE; if (!create_if_not_found) { dbus_move_error (&read_error, error); return FALSE; } /* If the file exists and contains junk, we want to keep that error * message instead of overwriting it with a "file exists" error * message when we try to write */ if (dbus_error_has_name (&read_error, DBUS_ERROR_INVALID_FILE_CONTENT)) { dbus_move_error (&read_error, error); return FALSE; } else { dbus_error_free (&read_error); return _dbus_create_uuid_file_exclusively (filename, uuid, error); } } _DBUS_DEFINE_GLOBAL_LOCK (machine_uuid); static int machine_uuid_initialized_generation = 0; static DBusGUID machine_uuid; /** * Gets the hex-encoded UUID of the machine this function is * executed on. This UUID is guaranteed to be the same for a given * machine at least until it next reboots, though it also * makes some effort to be the same forever, it may change if the * machine is reconfigured or its hardware is modified. * * @param uuid_str string to append hex-encoded machine uuid to * @returns #FALSE if no memory */ dbus_bool_t _dbus_get_local_machine_uuid_encoded (DBusString *uuid_str) { dbus_bool_t ok; _DBUS_LOCK (machine_uuid); if (machine_uuid_initialized_generation != _dbus_current_generation) { DBusError error = DBUS_ERROR_INIT; if (!_dbus_read_local_machine_uuid (&machine_uuid, FALSE, &error)) { #ifndef DBUS_BUILD_TESTS /* For the test suite, we may not be installed so just continue silently * here. But in a production build, we want to be nice and loud about * this. */ _dbus_warn_check_failed ("D-Bus library appears to be incorrectly set up; failed to read machine uuid: %s\n" "See the manual page for dbus-uuidgen to correct this issue.\n", error.message); #endif dbus_error_free (&error); _dbus_generate_uuid (&machine_uuid); } } ok = _dbus_uuid_encode (&machine_uuid, uuid_str); _DBUS_UNLOCK (machine_uuid); return ok; } #ifdef DBUS_BUILD_TESTS /** * Returns a string describing the given name. * * @param header_field the field to describe * @returns a constant string describing the field */ const char * _dbus_header_field_to_string (int header_field) { switch (header_field) { case DBUS_HEADER_FIELD_INVALID: return "invalid"; case DBUS_HEADER_FIELD_PATH: return "path"; case DBUS_HEADER_FIELD_INTERFACE: return "interface"; case DBUS_HEADER_FIELD_MEMBER: return "member"; case DBUS_HEADER_FIELD_ERROR_NAME: return "error-name"; case DBUS_HEADER_FIELD_REPLY_SERIAL: return "reply-serial"; case DBUS_HEADER_FIELD_DESTINATION: return "destination"; case DBUS_HEADER_FIELD_SENDER: return "sender"; case DBUS_HEADER_FIELD_SIGNATURE: return "signature"; default: return "unknown"; } } #endif /* DBUS_BUILD_TESTS */ #ifndef DBUS_DISABLE_CHECKS /** String used in _dbus_return_if_fail macro */ const char _dbus_return_if_fail_warning_format[] = "arguments to %s() were incorrect, assertion \"%s\" failed in file %s line %d.\n" "This is normally a bug in some application using the D-Bus library.\n"; #endif #ifndef DBUS_DISABLE_ASSERT /** * Internals of _dbus_assert(); it's a function * rather than a macro with the inline code so * that the assertion failure blocks don't show up * in test suite coverage, and to shrink code size. * * @param condition TRUE if assertion succeeded * @param condition_text condition as a string * @param file file the assertion is in * @param line line the assertion is in * @param func function the assertion is in */ void _dbus_real_assert (dbus_bool_t condition, const char *condition_text, const char *file, int line, const char *func) { if (_DBUS_UNLIKELY (!condition)) { _dbus_warn ("%lu: assertion failed \"%s\" file \"%s\" line %d function %s\n", _dbus_pid_for_log (), condition_text, file, line, func); _dbus_abort (); } } /** * Internals of _dbus_assert_not_reached(); it's a function * rather than a macro with the inline code so * that the assertion failure blocks don't show up * in test suite coverage, and to shrink code size. * * @param explanation what was reached that shouldn't have been * @param file file the assertion is in * @param line line the assertion is in */ void _dbus_real_assert_not_reached (const char *explanation, const char *file, int line) { _dbus_warn ("File \"%s\" line %d process %lu should not have been reached: %s\n", file, line, _dbus_pid_for_log (), explanation); _dbus_abort (); } #endif /* DBUS_DISABLE_ASSERT */ #ifdef DBUS_BUILD_TESTS static dbus_bool_t run_failing_each_malloc (int n_mallocs, const char *description, DBusTestMemoryFunction func, void *data) { n_mallocs += 10; /* fudge factor to ensure reallocs etc. are covered */ while (n_mallocs >= 0) { _dbus_set_fail_alloc_counter (n_mallocs); _dbus_verbose ("\n===\n%s: (will fail malloc %d with %d failures)\n===\n", description, n_mallocs, _dbus_get_fail_alloc_failures ()); if (!(* func) (data)) return FALSE; n_mallocs -= 1; } _dbus_set_fail_alloc_counter (_DBUS_INT_MAX); return TRUE; } /** * Tests how well the given function responds to out-of-memory * situations. Calls the function repeatedly, failing a different * call to malloc() each time. If the function ever returns #FALSE, * the test fails. The function should return #TRUE whenever something * valid (such as returning an error, or succeeding) occurs, and #FALSE * if it gets confused in some way. * * @param description description of the test used in verbose output * @param func function to call * @param data data to pass to function * @returns #TRUE if the function never returns FALSE */ dbus_bool_t _dbus_test_oom_handling (const char *description, DBusTestMemoryFunction func, void *data) { int approx_mallocs; const char *setting; int max_failures_to_try; int i; /* Run once to see about how many mallocs are involved */ _dbus_set_fail_alloc_counter (_DBUS_INT_MAX); _dbus_verbose ("Running once to count mallocs\n"); if (!(* func) (data)) return FALSE; approx_mallocs = _DBUS_INT_MAX - _dbus_get_fail_alloc_counter (); _dbus_verbose ("\n=================\n%s: about %d mallocs total\n=================\n", description, approx_mallocs); setting = _dbus_getenv ("DBUS_TEST_MALLOC_FAILURES"); if (setting != NULL) { DBusString str; long v; _dbus_string_init_const (&str, setting); v = 4; if (!_dbus_string_parse_int (&str, 0, &v, NULL)) _dbus_warn ("couldn't parse '%s' as integer\n", setting); max_failures_to_try = v; } else { max_failures_to_try = 4; } i = setting ? max_failures_to_try - 1 : 1; while (i < max_failures_to_try) { _dbus_set_fail_alloc_failures (i); if (!run_failing_each_malloc (approx_mallocs, description, func, data)) return FALSE; ++i; } _dbus_verbose ("\n=================\n%s: all iterations passed\n=================\n", description); return TRUE; } #endif /* DBUS_BUILD_TESTS */ /** @} */