base/backtrace: Add a generic backtrace generation library

Don't print the backtrace function in the backtrace

base/backtrace.cc

@@ -0,0 +1,40 @@
+/* <base/backtrace.cc>
+
+   Copyright 2010-2014 OrlyAtomics, Inc.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License. */
+
+#include <base/backtrace.h>
+
+#include <execinfo.h>
+
+#include <base/as_str.h>
+
+using namespace Base;
+
+void Base::GenBacktrace(int max_frame_count, const std::function<bool (const std::string &)> &cb) {
+  void *frames[max_frame_count+1];
+  int frame_count = backtrace(frames, max_frame_count+1);
+  char **symbols = backtrace_symbols(frames, frame_count);
+  for (int frame_idx = 1; frame_idx < frame_count; ++frame_idx) {
+    auto frame_print = AsStr('[', frame_idx, '/', frame_count-1, "][");
+    if (symbols) {
+      frame_print += symbols[frame_idx];
+    } else {
+      frame_print += AsStr(frames[frame_idx]);
+    }
+    if (!cb(frame_print)) {
+      return;
+    }
+  }
+}

base/backtrace.h

@@ -0,0 +1,29 @@
+/* <base/backtrace.h>
+
+   Print a backtrace
+
+   Copyright 2010-2014 OrlyAtomics, Inc.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License. */
+
+#pragma once
+
+#include <functional>
+#include <string>
+
+namespace Base {
+
+  /* Generate a backtrace one line at a time, calling the callback once for each backtrace frame. */
+  void GenBacktrace(int max_frame_count, const std::function<bool (const std::string &)> &cb);
+
+} // Base

bootstrap.sh

@@ -35,7 +35,7 @@ $CC -o tools/jhm
   jhm/env.cc jhm/jobs/compile_c_family.cc util/error.cc jhm/status_line.cc io/input_producer.cc                        \
   jhm/work_finder.cc base/fd.cc base/pump.cc util/io.cc base/split.cc jhm/config.cc jhm/jobs/link.cc                   \
   jhm/jobs/bison.cc strm/syntax_error.cc jhm/jobs/nycr.cc base/dir_walker.cc jhm/jobs/dep.cc util/time.cc              \
-  strm/out.cc base/event_semaphore.cc strm/in.cc strm/past_end.cc base/unreachable.cc base/path.cc                     \
+  strm/out.cc base/event_semaphore.cc strm/in.cc strm/past_end.cc base/unreachable.cc base/path.cc base/backtrace.cc   \
   -I./ -DSRC_ROOT=\"`pwd`\"                                                                                            \
   -msse2 -pthread
 
@@ -44,7 +44,7 @@ $CC -o tools/make_dep_file
   "${common_flags[@]}"                                                                                                 \
   strm/bin/var_int.cc strm/syntax_error.cc strm/out.cc strm/past_end.cc strm/in.cc strm/bin/in.cc                      \
   util/io.cc base/demangle.cc base/code_location.cc base/event_semaphore.cc util/error.cc base/unreachable.cc          \
-  jhm/make_dep_file.cc base/thrower.cc base/fd.cc base/split.cc base/subprocess.cc base/pump.cc                        \
+  jhm/make_dep_file.cc base/thrower.cc base/fd.cc base/split.cc base/subprocess.cc base/pump.cc base/backtrace.cc      \
   server/daemonize.cc                                                                                                  \
   -I./ -DSRC_ROOT=\"`pwd`\"                                                                                            \
   -msse2 -pthread

server/daemonize.cc

@@ -21,12 +21,12 @@
 #include <initializer_list>
 
 #include <signal.h>
-#include <execinfo.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <syslog.h>
 #include <sys/stat.h>
 
+#include <base/backtrace.h>
 #include <util/error.h>
 
 using namespace std;
@@ -61,18 +61,10 @@ static void InstallSignalHandlers(initializer_list<int> signals, void (*handler)
 }
 
 void Server::BacktraceToLog() {
-  static const int max_frame_count = 100;
-  void *frames[max_frame_count];
-  int frame_count = backtrace(frames, max_frame_count);
-  char **symbols = backtrace_symbols(frames, frame_count);
-  if (symbols) {
-    for (int frame_idx = 0; frame_idx < frame_count; ++frame_idx) {
-      syslog(LOG_ERR, "[backtrace][frame %d of %d][%s]", frame_idx + 1, frame_count, symbols[frame_idx]);
-    }
-    free(symbols);
-  } else {
-      syslog(LOG_ERR, "[backtrace][failed to get %d frames]", frame_count);
-  }
+  Base::GenBacktrace(100, [](const std::string &msg) {
+    syslog(LOG_ERR, "[backtrace]%s", msg.c_str());
+    return true;
+  });
 }
 
 pid_t Server::Daemonize() {