Add backtrace()

6 files changed, 292 insertions, 9 deletions

diff --git a/libbutl/backtrace.cxx b/libbutl/backtrace.cxx
new file mode 100644
index 0000000..7a8d615
--- /dev/null
+++ b/libbutl/backtrace.cxx
@@ -0,0 +1,101 @@
+// file      : libbutl/backtrace.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef __cpp_modules_ts
+#include <libbutl/backtrace.mxx>
+#endif
+
+// We only enable backtrace during bootstrap if we can do it without any
+// complications of the build scripts/makefiles.
+//
+// With glibc linking with -rdynamic gives (non-static) function names.
+// FreeBSD requires explicitly linking -lexecinfo.
+//
+#ifndef BUILD2_BOOTSTRAP
+#  if defined(__linux__) || \
+      defined(__APPLE__) || \
+      defined(__FreeBSD__)
+#    define LIBBUTL_BACKTRACE
+#  endif
+#else
+#  if defined(__linux__) || \
+      defined(__APPLE__)
+#    define LIBBUTL_BACKTRACE
+#  endif
+#endif
+
+#ifdef LIBBUTL_BACKTRACE
+#  include <stdlib.h>   // free()
+#  include <execinfo.h>
+#endif
+
+#include <cassert>
+
+#ifndef __cpp_lib_modules_ts
+#include <string>
+
+#ifdef LIBBUTL_BACKTRACE
+#  include <memory>  // unique_ptr
+#  include <cstddef> // size_t
+#endif
+
+#include <exception>
+#endif
+
+// Other includes.
+
+#ifdef __cpp_modules_ts
+module butl.backtrace;
+
+// Only imports additional to interface.
+#ifdef __clang__
+#ifdef __cpp_lib_modules_ts
+import std.core;
+#endif
+#endif
+
+#endif
+
+using namespace std;
+
+namespace butl
+{
+  string
+  backtrace () noexcept
+  try
+  {
+    string r;
+
+#ifdef LIBBUTL_BACKTRACE
+
+    // Note: backtrace() returns int on Linux and MacOS and size_t on FreeBSD.
+    //
+    void* buf[1024];
+    auto n (::backtrace (buf, 1024));
+
+    assert (n >= 0);
+
+    char** fs (backtrace_symbols (buf, n)); // Note: returns NULL on error.
+
+    if (fs != nullptr)
+    {
+      unique_ptr<char*, void (*)(char**)> deleter (
+        fs, [] (char** s) {::free (s);});
+
+      for (size_t i (0); i != static_cast<size_t> (n); ++i)
+      {
+        r += fs[i];
+        r += '\n';
+      }
+    }
+
+#endif
+
+    return r;
+  }
+  catch (const std::exception&)
+  {
+    return string ();
+  }
+}
diff --git a/libbutl/backtrace.mxx b/libbutl/backtrace.mxx
new file mode 100644
index 0000000..25d0dcd
--- /dev/null
+++ b/libbutl/backtrace.mxx
@@ -0,0 +1,43 @@
+// file      : libbutl/backtrace.mxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef __cpp_modules_ts
+#pragma once
+#endif
+
+// C includes.
+
+#ifndef __cpp_lib_modules_ts
+#include <string>
+#endif
+
+// Other includes.
+
+#ifdef __cpp_modules_ts
+export module butl.backtrace;
+#ifdef __cpp_lib_modules_ts
+import std.core;
+#endif
+#endif
+
+#include <libbutl/export.hxx>
+
+LIBBUTL_MODEXPORT namespace butl
+{
+  // Return the calling thread's backtrace or empty string if this
+  // functionality is not supported or an error has occurred. The exact
+  // backtrace format is implementation-defined; it normally contains a line
+  // with the binary name, address in that binary, and, if available, the
+  // function name for each stack frame.
+  //
+  // Currently this functionality is only available on Linux, FreeBSD, and Mac
+  // OS. On the first two platforms the address can be mapped to the function
+  // name and, if built with debug info, to source location using the
+  // addr2line(1) utility:
+  //
+  // $ addr2line -f -C -e <binary> <addr>
+  //
+  LIBBUTL_SYMEXPORT std::string
+  backtrace () noexcept;
+}
diff --git a/libbutl/buildfile b/libbutl/buildfile
index 8e88402..feb2f96 100644
--- a/libbutl/buildfile
+++ b/libbutl/buildfile
@@ -16,7 +16,15 @@ lib{butl}: {hxx ixx txx cxx}{** -uuid-* +uuid-io -win32-utility} \
            hxx{**.hxx -uuid-*.hxx +uuid-io.hxx -win32-utility.hxx \
                -version.hxx} hxx{version}
 
-windows = ($cxx.target.class == 'windows')
+tclass = $cxx.target.class
+tsys   = $cxx.target.system
+
+linux   = ($tclass == 'linux')
+macos   = ($tclass == 'macos')
+windows = ($tclass == 'windows')
+freebsd = ($tsys == 'freebsd')
+
+mingw = ($tsys == 'mingw32')
 
 # Exclude these from compilation on non-Windows targets.
 #
@@ -30,17 +38,19 @@ lib{butl}: file{*.c *.h}
 
 # Platform-specific UUID implementations.
 #
-lib{butl}: cxx{uuid-linux}:   include = ($cxx.target.class  == 'linux')
-lib{butl}: cxx{uuid-macos}:   include = ($cxx.target.class  == 'macos')
+lib{butl}: cxx{uuid-linux}:   include = $linux
+lib{butl}: cxx{uuid-macos}:   include = $macos
 lib{butl}: cxx{uuid-windows}: include = $windows
-lib{butl}: cxx{uuid-freebsd}: include = ($cxx.target.system == 'freebsd')
+lib{butl}: cxx{uuid-freebsd}: include = $freebsd
 
-if ($cxx.target.class == 'linux')
+if $linux
   cxx.libs += -ldl
-elif ($cxx.target.class == 'macos')
+elif $macos
   cxx.libs += -framework CoreFoundation
-elif ($windows)
-  cxx.libs += ($cxx.target.system == 'mingw32' ? -lrpcrt4 : rpcrt4.lib)
+elif $windows
+  cxx.libs += ($mingw ? -lrpcrt4 : rpcrt4.lib)
+elif $freebsd
+  cxx.libs += -lexecinfo
 
 # Include the generated version header into the distribution (so that we don't
 # pick up an installed one) and don't remove it when cleaning in src (so that
@@ -63,7 +73,7 @@ objs{*} bmis{*}: cxx.poptions += -DLIBBUTL_SHARED_BUILD
 # Additional system libraries.
 #
 if $windows
-  cxx.libs += ($cxx.target.system == 'mingw32' ? -limagehlp : imagehlp.lib)
+  cxx.libs += ($mingw ? -limagehlp : imagehlp.lib)
 else
   cxx.libs += -lpthread
 
diff --git a/tests/backtrace/buildfile b/tests/backtrace/buildfile
new file mode 100644
index 0000000..a4120df
--- /dev/null
+++ b/tests/backtrace/buildfile
@@ -0,0 +1,12 @@
+# file      : tests/backtrace/buildfile
+# copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+# license   : MIT; see accompanying LICENSE file
+
+import libs = libbutl%lib{butl}
+
+exe{driver}: {hxx cxx}{*} $libs testscript
+
+# Make sure backtrace() includes function names.
+#
+if ($cxx.target.class == 'linux')
+  cxx.loptions += -rdynamic
diff --git a/tests/backtrace/driver.cxx b/tests/backtrace/driver.cxx
new file mode 100644
index 0000000..5fd9223
--- /dev/null
+++ b/tests/backtrace/driver.cxx
@@ -0,0 +1,97 @@
+// file      : tests/backtrace/driver.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef _WIN32
+#  include <sys/resource.h> // setrlimit()
+#endif
+
+#include <cassert>
+
+#ifndef __cpp_lib_modules_ts
+#include <string>
+#include <iostream>
+#include <exception>    // set_terminate(), terminate_handler
+#include <system_error>
+#else
+import std.io;
+#endif
+
+// Other includes.
+
+#ifdef __cpp_modules_ts
+#ifdef __cpp_lib_modules_ts
+import std.core;
+#endif
+import butl.process;
+import butl.backtrace;
+#else
+#include <libbutl/process.mxx>
+#include <libbutl/backtrace.mxx>
+#endif
+
+using namespace std;
+using namespace butl;
+
+namespace test
+{
+  // Note: is not static to make sure the stack frame is not optimized out.
+  //
+  int
+  func ()
+  {
+    throw system_error (EINVAL, generic_category ());
+  }
+}
+
+static terminate_handler def_term_handler;
+
+// Usage: argv[0] [-c]
+//
+// Print the backtrace for an unhandled exception.
+//
+// -c
+//    Run as a child process that sets up the backtrace-printing terminate
+//    handler and throws unhandled exception.
+int
+main (int argc, const char* argv[])
+{
+  // Not to cause the testscript to fail due to the abnormal test driver
+  // termination, delegate the unhandled exception backtrace printing to the
+  // child process.
+  //
+  bool child (false);
+  for (int i (1); i != argc; ++i)
+  {
+    string o (argv[i]);
+
+    if (o == "-c")
+      child = true;
+    else
+      assert (false);
+  }
+
+  if (child)
+  {
+    // Disable dumping core file on POSIX.
+    //
+#ifndef _WIN32
+    struct rlimit rlim {0, 0};
+    assert (setrlimit (RLIMIT_CORE, &rlim) == 0);
+#endif
+
+    def_term_handler = set_terminate ([]()
+                                      {
+                                        cerr << backtrace ();
+
+                                        if (def_term_handler != nullptr)
+                                          def_term_handler ();
+                                      });
+
+    return test::func ();
+  }
+
+  // Report failure with non-zero code if child succeeds.
+  //
+  return process_run (0, 1, 2, argv[0], "-c") ? 1 : 0;
+}
diff --git a/tests/backtrace/testscript b/tests/backtrace/testscript
new file mode 100644
index 0000000..bdcd147
--- /dev/null
+++ b/tests/backtrace/testscript
@@ -0,0 +1,20 @@
+# file      : tests/backtrace/testscript
+# copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+# license   : MIT; see accompanying LICENSE file
+
+tclass = $cxx.target.class
+tsys   = $cxx.target.system
+
+: basic
+:
+if ($tclass == 'linux' || $tclass == 'macos' || $tsys == 'freebsd')
+{
+  # The stack frame line format varies among OSes. The only common thing is
+  # the '0x' function address prefix.
+  #
+  $* 2>>~%EOE%
+    %.*
+    %.*0x.*%
+    %.*
+    EOE
+}