Tests for backtrace.c

These need to be a separate executable, since the point of backtrace.c
is that it can crash and write stuff.

.gitignore

@@ -164,9 +164,11 @@
 /src/test/bench
 /src/test/bench.exe
 /src/test/test
+/src/test/test-bt-cl
 /src/test/test-child
 /src/test/test-ntor-cl
 /src/test/test.exe
+/src/test/test-bt-cl.exe
 /src/test/test-child.exe
 /src/test/test-ntor-cl.exe
 

src/test/bt_test.py

@@ -0,0 +1,42 @@
+# Copyright 2013, The Tor Project, Inc
+# See LICENSE for licensing information
+
+"""
+bt_test.py
+
+This file tests the output from test-bt-cl to make sure it's as expected.
+
+Example usage:
+
+$ ./src/test/test-bt-cl crash | ./src/test/bt_test.py
+OK
+$ ./src/test/test-bt-cl assert | ./src/test/bt_test.py
+OK
+
+"""
+
+import sys
+
+
+def matches(lines, funcs):
+    if len(lines) < len(funcs):
+        return False
+    try:
+        for l, f in zip(lines, funcs):
+            l.index(f)
+    except ValueError:
+        return False
+    else:
+        return True
+
+FUNCNAMES = "crash oh_what a_tangled_web we_weave main".split()
+
+LINES = sys.stdin.readlines()
+
+for I in range(len(LINES)):
+    if matches(LINES[I:], FUNCNAMES):
+        print "OK"
+        break
+else:
+    print "BAD"
+

src/test/include.am

@@ -77,3 +77,11 @@ src_test_test_ntor_cl_AM_CPPFLAGS =	       \
 
 endif
 
+noinst_PROGRAMS += src/test/test-bt-cl
+src_test_test_bt_cl_SOURCES = src/test/test_bt_cl.c
+src_test_test_bt_cl_LDADD = src/common/libor-testing.a \
+	@TOR_LIB_MATH@ \
+	@TOR_LIB_WS32@ @TOR_LIB_GDI@
+src_test_test_bt_cl_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+src_test_test_bt_cl_CPPFLAGS= $(src_test_AM_CPPFLAGS)
+

src/test/test_bt_cl.c

@@ -0,0 +1,110 @@
+/* Copyright (c) 2012-2013, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "orconfig.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "or.h"
+#include "util.h"
+#include "backtrace.h"
+#include "torlog.h"
+
+
+/* -1: no crash.
+ *  0: crash with a segmentation fault.
+ *  1x: crash with an assertion failure. */
+static int crashtype = 0;
+
+#ifdef __GNUC__
+#define NOINLINE __attribute__((noinline))
+#define NORETURN __attribute__((noreturn))
+#endif
+
+int crash(int x) NOINLINE;
+int oh_what(int x) NOINLINE;
+int a_tangled_web(int x) NOINLINE;
+int we_weave(int x) NOINLINE;
+static void abort_handler(int s) NORETURN;
+
+int
+crash(int x)
+{
+  if (crashtype == 0) {
+    *(volatile int *)0 = 0;
+  } else if (crashtype == 1) {
+    tor_assert(1 == 0);
+  } else if (crashtype == -1) {
+    ;
+  }
+
+  crashtype *= x;
+  return crashtype;
+}
+
+int
+oh_what(int x)
+{
+  /* We call crash() twice here, so that the compiler won't try to do a
+   * tail-call optimization.  Only the first call will actually happen, but
+   * telling the compiler to maybe do the second call will prevent it from
+   * replacing the first call with a jump. */
+  return crash(x) + crash(x*2);
+}
+
+int
+a_tangled_web(int x)
+{
+  return oh_what(x) * 99 + oh_what(x);
+}
+
+int
+we_weave(int x)
+{
+  return a_tangled_web(x) + a_tangled_web(x+1);
+}
+
+static void
+abort_handler(int s)
+{
+  (void)s;
+  exit(0);
+}
+
+int
+main(int argc, char **argv)
+{
+  log_severity_list_t severity;
+
+  if (argc < 2) {
+    puts("I take an argument. It should be \"assert\" or \"crash\" or "
+         "\"none\"");
+    return 1;
+  }
+  if (!strcmp(argv[1], "assert")) {
+    crashtype = 1;
+  } else if (!strcmp(argv[1], "crash")) {
+    crashtype = 0;
+  } else if (!strcmp(argv[1], "none")) {
+    crashtype = -1;
+  } else {
+    puts("Argument should be \"assert\" or \"crash\" or \"none\"");
+    return 1;
+  }
+
+  init_logging();
+  set_log_severity_config(LOG_WARN, LOG_ERR, &severity);
+  add_stream_log(&severity, "stdout", STDOUT_FILENO);
+  tor_log_update_sigsafe_err_fds();
+
+  configure_backtrace_handler(NULL);
+
+  signal(SIGABRT, abort_handler);
+
+  printf("%d\n", we_weave(2));
+
+  clean_up_backtrace_handler();
+
+  return 0;
+}
+

src/test/test_logging.c

@@ -96,6 +96,8 @@ test_sigsafe_err(void *arg)
   close(STDERR_FILENO);
   log_err(LD_BUG, "Say, this isn't too cool.");
   tor_log_err_sigsafe("Minimal.\n", NULL);
+
+  set_log_time_granularity(100*1000);
   tor_log_err_sigsafe("Testing any ",
                       "attempt to manually log ",
                       "from a signal.\n",