[ptxdist] [PATCH 2/2] os: Add execinfo::backtrace()

[bernhard@bwalle.de]

From: Bernhard Walle <walle@corscience.de>

Signed-off-by: Bernhard Walle <walle@corscience.de>
---
 NEWS                          |    2 +-
 csstdxx/CMakeLists.txt        |    2 ++
 csstdxx/os/execinfo.h         |   53 ++++++++++++++++++++++++++++++++++
 csstdxx/os/execinfo_linux.cpp |   64 +++++++++++++++++++++++++++++++++++++++++
 examples/os/CMakeLists.txt    |    4 +++
 examples/os/backtrace.cpp     |   27 +++++++++++++++++
 tests/test_os.cpp             |    7 +++++
 tests/test_os.h               |    2 ++
 8 files changed, 160 insertions(+), 1 deletion(-)
 create mode 100644 csstdxx/os/execinfo_linux.cpp
 create mode 100644 examples/os/backtrace.cpp

diff --git a/NEWS b/NEWS
index 752220a..213cda4 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,6 @@
 0.5.1
 -----
- * os: Add execinfo::demangleCxxName().
+ * os: Add execinfo::demangleCxxName() and execinfo::backtrace().
 
 0.5.0
 -----
diff --git a/csstdxx/CMakeLists.txt b/csstdxx/CMakeLists.txt
index 71af070..d26c568 100644
--- a/csstdxx/CMakeLists.txt
+++ b/csstdxx/CMakeLists.txt
@@ -125,6 +125,8 @@ endif (WITH_SERIAL_BUS_ACCESS)
 
 if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
     set(CSSTDXX_SRC ${CSSTDXX_SRC}
+        os/execinfo_linux.cpp
+
         datetime/systemclock_linux.cpp
 
         io/iotimer_linux.cpp
diff --git a/csstdxx/os/execinfo.h b/csstdxx/os/execinfo.h
index 49cc21f..7772f4e 100644
--- a/csstdxx/os/execinfo.h
+++ b/csstdxx/os/execinfo.h
@@ -55,6 +55,59 @@ namespace execinfo {
  */
 std::string demangleCxxName(const char *name, bool *ok=NULL);
 
+/**
+ * \brief Returns a backtrace from the current stack
+ *
+ * It depends on the implementation how the backtrace looks like. Here's an example
+ * (x86_64, gcc, Linux):
+ *
+ * \verbatim
+/home/bwalle/devel/CSstdxx/CSstdxx/build/csstdxx/libcsstdxx.so.2(cs::os::execinfo::backtrace()+0x49) [0x7f8e7402594d]
+build/examples/os/backtrace(sigsegvhandler(int)+0x18) [0x400ccc]
+/lib/libc.so.6(+0x349f0) [0x7f8e72f819f0]
+build/examples/os/backtrace(foo(int)+0x1d) [0x400d2d]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(foo(int)+0x37) [0x400d47]
+build/examples/os/backtrace(main+0x28) [0x400d71]
+/lib/libc.so.6(__libc_start_main+0xed) [0x7f8e72f6e38d]
+build/examples/os/backtrace() [0x400bf9]
+\endverbatim
+ *
+ * As you see, the function names are demangled and there \b are function names.
+ * To get that on Linux/gcc, you must compile your application and all libraries
+ * from which a backtrace should be obtained with the <tt>-rdynamic</tt> command line
+ * parameter. This is the default for CMake.
+ *
+ * The example <tt>backtrace.cpp</tt> shows how to use backtrace to print something
+ * useful when the application receives a segmentation fault.
+ *
+ * \note Don't try to parse the output. Just use it for debugging.
+ *
+ * \return the backtrace as shown above on success or an empty string on failure.
+ * \since 0.5.1
+ * \ingroup os_execinfo
+ * \sa http://en.wikipedia.org/wiki/Name_mangling
+ */
+std::string backtrace();
+
 } // namespace execinfo
 } // namespace os
 } // namespace cs
diff --git a/csstdxx/os/execinfo_linux.cpp b/csstdxx/os/execinfo_linux.cpp
new file mode 100644
index 0000000..5516292
--- /dev/null
+++ b/csstdxx/os/execinfo_linux.cpp
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) Corscience GmbH & Co. KG
+ *
+ * Projectname - Redmine:CSstdxx
+ * Module ID - os
+ */
+
+#include <csstdxx/config.h>
+#include <cstdlib>
+#include <sstream>
+#include <execinfo.h>
+
+#include "execinfo.h"
+
+#ifdef HAVE_CXXABI_H
+#  include <cxxabi.h>
+#endif
+
+namespace cs {
+namespace os {
+namespace execinfo {
+
+#define BACKTRACE_MAX 100
+
+std::string backtrace()
+{
+    std::stringstream ss;
+
+    void *buffer[100];
+    int nptrs = ::backtrace(buffer, BACKTRACE_MAX);
+    if (nptrs == 0)
+        return std::string();
+
+    char **strings = backtrace_symbols(buffer, nptrs);
+    if (!strings)
+        return std::string();
+
+    for (int i = 0; i < nptrs; i++) {
+        // demangle names if possible
+        std::string line = strings[i];
+        size_t openBrace = line.find('(');
+        size_t plus = line.find('+', openBrace);
+
+        if ((openBrace == std::string::npos) || (plus == std::string::npos)) {
+            ss << line << std::endl;
+            continue;
+        }
+
+        std::string function = line.substr(openBrace+1, plus-openBrace-1);
+        function = demangleCxxName(function.c_str());
+
+        ss << line.substr(0, openBrace+1)
+           << function
+           << line.substr(plus) << std::endl;
+    }
+
+    free(strings);
+
+    return ss.str();
+}
+
+} // namespace execinfo
+} // namespace os
+} // namespace cs
diff --git a/examples/os/CMakeLists.txt b/examples/os/CMakeLists.txt
index e117fb7..4b20733 100644
--- a/examples/os/CMakeLists.txt
+++ b/examples/os/CMakeLists.txt
@@ -29,6 +29,10 @@ add_executable(c++filt c++filt.cpp)
 target_link_libraries(c++filt csstdxx)
 set(EXAMPLE_PROGRAMS ${EXAMPLE_PROGRAMS} c++filt)
 
+add_executable(backtrace backtrace.cpp)
+target_link_libraries(backtrace csstdxx)
+set(EXAMPLE_PROGRAMS ${EXAMPLE_PROGRAMS} backtrace)
+
 if (INSTALL_CSSTDXX_EXAMPLES)
     install(TARGETS ${EXAMPLE_PROGRAMS} DESTINATION bin/csstdxx)
 endif (INSTALL_CSSTDXX_EXAMPLES)
diff --git a/examples/os/backtrace.cpp b/examples/os/backtrace.cpp
new file mode 100644
index 0000000..ca6bd9d
--- /dev/null
+++ b/examples/os/backtrace.cpp
@@ -0,0 +1,27 @@
+#include <csignal>
+#include <cstdio>
+#include <csstdxx/os.h>
+
+void sigsegvhandler(int signal)
+{
+    puts(cs::os::execinfo::backtrace().c_str());
+    _exit(1);
+}
+
+int foo(int x)
+{
+    if (x == 0) {
+        volatile int *p = NULL;
+        *p = 20;
+        return 0;
+    }
+    else
+        return foo(x-1);
+}
+
+int main(int argc, char *argv[])
+{
+    signal(SIGSEGV, sigsegvhandler);
+    foo(20);
+    return 0;
+}
diff --git a/tests/test_os.cpp b/tests/test_os.cpp
index 683e875..c36e719 100644
--- a/tests/test_os.cpp
+++ b/tests/test_os.cpp
@@ -477,6 +477,13 @@ void TestExecinfo::testCppDemangle()
     CPPUNIT_ASSERT_EQUAL(std::string("blablubb"), result);
 }
 
+void TestExecinfo::testBacktrace()
+{
+#ifdef __linux__
+    CPPUNIT_ASSERT(!execinfo::backtrace().empty());
+#endif
+}
+
 }  // namespace os
 }  // namespace cs
 
diff --git a/tests/test_os.h b/tests/test_os.h
index a95d0a9..58ba5d3 100644
--- a/tests/test_os.h
+++ b/tests/test_os.h
@@ -121,10 +121,12 @@ class TestExecinfo : public CppUnit::TestFixture
 {
 public:
     void testCppDemangle();
+    void testBacktrace();
 
 private:
     CPPUNIT_TEST_SUITE(TestExecinfo);
     CPPUNIT_TEST(testCppDemangle);
+    CPPUNIT_TEST(testBacktrace);
     CPPUNIT_TEST_SUITE_END();
 };
 
-- 
1.7.9.4


-- 
ptxdist mailing list
ptxdist@pengutronix.de