147 lines
6.1 KiB
Markdown
147 lines
6.1 KiB
Markdown
# Pretty Stack Trace library
|
|
|
|
## Table of Contents
|
|
* [Dependencies](#dependencies)
|
|
|
|
* [Commands to work with debug information](#commands-to-work-with-debug-information)
|
|
|
|
* [Unwinding-related gcc options](#unwinding-related-gcc-options)
|
|
|
|
* [Useful links](#useful-links)
|
|
|
|
The goal of the project is to enable C/C++ developers to get informative stack trace in case of program crash (inside of signal handler). Key feature is to log not only function address/name/line etc but (if DWARF .debug_info section is present) values of function's parameters and variables.
|
|
|
|
Currently development focused on x86_64 architecture and for Linux OS, but further may be expanded to other architectures and OS if it will be demanded and some people will like to contribute to the project to support this architecture and OS.
|
|
|
|
As a first stage the goal is to dump only C/C++ base types such as pointer, boolean, integer etc.
|
|
|
|
Second stage dump composite types such as C structures, C++ classes, arrays etc.
|
|
|
|
Third stage to dump dereferenced pointers to data types with pointer validation.
|
|
|
|
## Dependencies
|
|
|
|
Currently library mostly depends on libunwind library which used to unwind function's stack frames from stack in signal handler, and libdw library which gives access to DWARF information of executed process if it present.
|
|
|
|
## commands to work with debug information
|
|
|
|
produce very simple debug info without sources
|
|
`echo 'void foo () {}' | gcc -g -O99 -o - -S -xc - -dA | grep frame_base`
|
|
|
|
dump .debug_info section
|
|
|
|
`readelf --debug-dump=info ./build/trace`
|
|
|
|
`objdump --dwarf=info ./build/trace`
|
|
|
|
dump symbol tables of executable
|
|
|
|
`readelf -s ./build/trace`
|
|
|
|
dump file segment headers
|
|
|
|
`readelf -l ./build/trace`
|
|
|
|
dump .eh_frame section
|
|
|
|
`readelf --debug-dump=frames simple`
|
|
|
|
dump list of sections
|
|
|
|
`readelf -S ./build/trace`
|
|
|
|
dump lie section
|
|
|
|
`objdump --dwarf=decodedline `
|
|
|
|
disassemble executable
|
|
|
|
`objdump --d ./build/trace`
|
|
|
|
## unwinding-related gcc options
|
|
*-funwind-tables* tells linker to generate .eh_frame section containing CFI. enabled by default if gcc/g++ used for linking
|
|
*-fexceptions* Enable exception handling. Generates extra code needed to propagate exceptions.
|
|
*-rdynamic* exports the symbols of an executable, allows to print function names in backtrace
|
|
*-fno-omit-frame-pointer* instructs the compiler to store the stack frame pointer in a register RBP for x86_64.
|
|
|
|
## Useful links
|
|
|
|
## Assembler tutorials
|
|
|
|
[Calling conventions](https://en.wikibooks.org/wiki/X86_Disassembly/Calling_Conventions)
|
|
|
|
[Functions and stack frames](https://en.wikibooks.org/wiki/X86_Disassembly/Functions_and_Stack_Frames)
|
|
|
|
[x86 Assembli guide](http://www.cs.virginia.edu/~evans/cs216/guides/x86.html)
|
|
|
|
[GNU extended Asm](https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html)
|
|
|
|
## DWARF links
|
|
|
|
[DWARF 5 Standard (DWARF comittee)](http://www.dwarfstd.org/doc/DWARF5.pdf)
|
|
|
|
[Introduction to the DWARF Debugging Format (DWARF comittee)](http://www.dwarfstd.org/doc/Debugging%20using%20DWARF-2012.pdf)
|
|
|
|
[Exception handling (DWARF wiki)](http://wiki.dwarfstd.org/index.php?title=Exception_Handling)
|
|
|
|
[Expression Operator For Constants (DWARF Wiki)](http://wiki.dwarfstd.org/index.php?title=Expression_Operator_For_Constants)
|
|
|
|
[Very good explanation what's CFA on x86_64](https://www.corsix.org/content/cfa-rsp-x86-64)
|
|
|
|
[Very informative discussion on dwarf mailing lists about DW_OP_regX vs. DW_OP_bregX 0 ](http://lists.dwarfstd.org/pipermail/dwarf-discuss-dwarfstd.org/2009-February/002056.html)
|
|
|
|
[Very informative discussion on dwarf mailing list about Semantics of DW_OP_(b)reg](http://lists.dwarfstd.org/pipermail/dwarf-discuss-dwarfstd.org/2017-March/004335.html)
|
|
|
|
[DW_AT_call_site_XXX (which currently is DW_AT_GNU_call_site_XXX) explanation](http://www.dwarfstd.org/ShowIssue.php?issue=100909.2&type=open)
|
|
|
|
[Exploring the DWARF debug format information (IBM)](https://developer.ibm.com/articles/au-dwarf-debug-format/)
|
|
|
|
[DWARF: function return value types and parameter types (simple tutorial)](https://simonkagstrom.livejournal.com/51001.html)
|
|
|
|
[Exploiting the Hard-Working DWARF (slides)](https://www.usenix.org/legacy/events/woot11/tech/slides/oakley.pdf)
|
|
|
|
[Exploiting the Hard-Working DWARF (article)](https://www.cs.dartmouth.edu/~trdata/reports/TR2011-688.pdf)
|
|
|
|
[Local variable location from DWARF info in ARM](https://stackoverflow.com/questions/47359841/local-variable-location-from-dwarf-info-in-arm)
|
|
|
|
[Reliable and Fast DWARF-Based Stack Unwinding](https://hal.inria.fr/hal-02297690/document)
|
|
|
|
[Improving debug info for optimized away parameters (GCC summit 2012, GNU extensions)](https://gcc.gnu.org/wiki/summit2010?action=AttachFile&do=get&target=jelinek.pdf)
|
|
|
|
[VARIABLE TRACKING AT ASSIGNMENTS (Redhat, with link to GCC Wiki)](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/developer_guide/ch-debug-vta)
|
|
|
|
[Good .eh_frame explanation](https://www.airs.com/blog/archives/460)
|
|
|
|
[Good itroduction to Debug information](https://engineering.backtrace.io/posts/dwarf/)
|
|
|
|
[libdwarf example](https://gist.github.com/jsoffer/9e63f2e58ebd90e81b24)
|
|
|
|
## Stack trace and other
|
|
|
|
[System V ABI](https://www.uclibc.org/docs/psABI-x86_64.pdf)
|
|
|
|
[Programmatic access to the call stack in C++](https://eli.thegreenplace.net/2015/programmatic-access-to-the-call-stack-in-c/)
|
|
|
|
[Where the top of the stack is on x86]()
|
|
|
|
[Stack frame layout on x86-64](https://eli.thegreenplace.net/2011/09/06/stack-frame-layout-on-x86-64)
|
|
|
|
[Retrieving function arguments while unwinding the stack](https://nikhilism.com/post/2019/retrieving-function-arguments-while-unwinding-the-stack/)
|
|
|
|
[Deep Wizardry: Stack Unwinding (more-less helpful)](http://blog.reverberate.org/2013/05/deep-wizardry-stack-unwinding.html)
|
|
|
|
[Writing a Linux Debugger Part 8: Stack unwinding (other related articles also interesting)](https://blog.tartanllama.xyz/writing-a-linux-debugger-unwinding/)
|
|
|
|
|
|
|
|
## Miscellaneous
|
|
|
|
[Testing pointers for validity (C/C++) (using system calls)](https://stackoverflow.com/questions/551069/testing-pointers-for-validity-c-c)
|
|
|
|
[Another way for testing pointer to validity (via procfs)](https://mischasan.wordpress.com/2011/04/11/interjection-why-no-linux-isbadreadptr/)
|
|
|
|
[Implementing a Debugger: The Fundamentals](https://engineering.backtrace.io/posts/2016-08-11-debugger-internals/)
|
|
|
|
|
|
|