Merge remote-tracking branch 'tor-github/pr/1277' into maint-0.3.5 (aee966cb) · Commits · ZerXes / Tor

changes/bug31571

0 → 100644

+7 −0

Original line number	Diff line number	Diff line
		o Minor bugfixes (error handling):
		- Report the tor version whenever an assertion fails. Previously, we only
		reported the Tor version on some crashes, and some non-fatal assertions.
		Fixes bug 31571; bugfix on 0.3.5.1-alpha.
		- On abort, try harder to flush the output buffers of log messages. On
		some platforms (macOS), log messages can be discarded when the process
		terminates. Fixes bug 31571; bugfix on 0.3.5.1-alpha.

src/lib/err/backtrace.c

+31 −11

Original line number	Diff line number	Diff line
		@@ -68,10 +68,10 @@
		// Redundant with util.h, but doing it here so we can avoid that dependency.
		#define raw_free free

		#ifdef USE_BACKTRACE
		/** Version of Tor to report in backtrace messages. */
		static char bt_version[128] = "";

		#ifdef USE_BACKTRACE
		/** Largest stack depth to try to dump. */
		#define MAX_DEPTH 256
		/** Static allocation of stack to dump. This is static so we avoid stack
		@@ -127,7 +127,7 @@ log_backtrace_impl(int severity, int domain, const char *msg,
		depth = backtrace(cb_buf, MAX_DEPTH);
		symbols = backtrace_symbols(cb_buf, (int)depth);

		logger(severity, domain, "%s. Stack trace:", msg);
		logger(severity, domain, "%s: %s. Stack trace:", bt_version, msg);
		if (!symbols) {
		/* LCOV_EXCL_START -- we can't provoke this. */
		logger(severity, domain, " Unable to generate backtrace.");
		@@ -193,15 +193,12 @@ dump_stack_symbols_to_error_fds(void)
		/** Install signal handlers as needed so that when we crash, we produce a
		* useful stack trace. Return 0 on success, -errno on failure. */
		static int
		install_bt_handler(const char *software)
		install_bt_handler(void)
		{
		int trap_signals[] = { SIGSEGV, SIGILL, SIGFPE, SIGBUS, SIGSYS,
		SIGIO, -1 };
		int i, rv=0;

		strncpy(bt_version, software, sizeof(bt_version) - 1);
		bt_version[sizeof(bt_version) - 1] = 0;

		struct sigaction sa;

		memset(&sa, 0, sizeof(sa));
		@@ -243,13 +240,13 @@ void
		log_backtrace_impl(int severity, int domain, const char *msg,
		tor_log_fn logger)
		{
		logger(severity, domain, "%s. (Stack trace not available)", msg);
		logger(severity, domain, "%s: %s. (Stack trace not available)",
		bt_version, msg);
		}

		static int
		install_bt_handler(const char *software)
		install_bt_handler(void)
		{
		(void) software;
		return 0;
		}

		@@ -264,6 +261,14 @@ dump_stack_symbols_to_error_fds(void)
		}
		#endif /* defined(NO_BACKTRACE_IMPL) */

		/** Return the tor version used for error messages on crashes.
		* Signal-safe: returns a pointer to a static array. */
		const char *
		get_tor_backtrace_version(void)
		{
		return bt_version;
		}

		/** Set up code to handle generating error messages on crashes. */
		int
		configure_backtrace_handler(const char *tor_version)
		@@ -271,10 +276,25 @@ configure_backtrace_handler(const char *tor_version)
		char version[128] = "Tor\0";

		if (tor_version) {
		snprintf(version, sizeof(version), "Tor %s", tor_version);
		int snp_rv = 0;
		/* We can't use strlcat() here, because it is defined in
		* string/compat_string.h on some platforms, and string uses torerr. */
		snp_rv = snprintf(version, sizeof(version), "Tor %s", tor_version);
		/* It's safe to call raw_assert() here, because raw_assert() does not
		* call configure_backtrace_handler(). */
		raw_assert(snp_rv < (int)sizeof(version));
		raw_assert(snp_rv >= 0);
		}

		return install_bt_handler(version);
		char *str_rv = NULL;
		/* We can't use strlcpy() here, see the note about strlcat() above. */
		str_rv = strncpy(bt_version, version, sizeof(bt_version) - 1);
		/* We must terminate bt_version, then raw_assert(), because raw_assert()
		* uses bt_version. */
		bt_version[sizeof(bt_version) - 1] = 0;
		raw_assert(str_rv == bt_version);

		return install_bt_handler();
		}

		/** Perform end-of-process cleanup for code that generates error messages on

src/lib/err/backtrace.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@ void log_backtrace_impl(int severity, int domain, const char *msg,
		int configure_backtrace_handler(const char *tor_version);
		void clean_up_backtrace_handler(void);
		void dump_stack_symbols_to_error_fds(void);
		const char *get_tor_backtrace_version(void);

		#define log_backtrace(sev, dom, msg) \
		log_backtrace_impl((sev), (dom), (msg), tor_log)

src/lib/err/torerr.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -144,14 +144,21 @@ tor_raw_assertion_failed_msg_(const char file, int line, const char expr,
		{
		char linebuf[16];
		format_dec_number_sigsafe(line, linebuf, sizeof(linebuf));
		tor_log_err_sigsafe("INTERNAL ERROR: Raw assertion failed at ",
		file, ":", linebuf, ": ", expr, NULL);
		tor_log_err_sigsafe("INTERNAL ERROR: Raw assertion failed in ",
		get_tor_backtrace_version(), " at ",
		file, ":", linebuf, ": ", expr, "\n", NULL);
		if (msg) {
		tor_log_err_sigsafe_write(msg);
		tor_log_err_sigsafe_write("\n");
		}

		dump_stack_symbols_to_error_fds();

		/* Some platforms (macOS, maybe others?) can swallow the last write before an
		* abort. This issue is probably caused by a race condition between write
		* buffer cache flushing, and process termination. So we write an extra
		* newline, to make sure that the message always gets through. */
		tor_log_err_sigsafe_write("\n");
		}

		/* As format_{hex,dex}_number_sigsafe, but takes a <b>radix</b> argument