posix_backtrace.cpp
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#include "crucible/core/backtrace.hpp"
#include "crucible/core/demangle.hpp"
#include "crucible/core/format.hpp"
#include <dlfcn.h>
#include <execinfo.h>
#include <cstddef>
#include <cstring>
#include <mutex>
#include <utility>
namespace crucible::core
{
namespace
{
constexpr std::size_t MAXIMUM_STACK_FRAMES { 1024 };
std::mutex backtrace_mutex;
}
auto backtrace() -> Backtrace_Result<Heap_Buffer<Stack_Frame>>
{
std::unique_lock<std::mutex> const backtrace_lock { backtrace_mutex };
Heap_Buffer<Stack_Frame> result {};
void *stack_data[MAXIMUM_STACK_FRAMES];
int const stack_size { ::backtrace(stack_data, MAXIMUM_STACK_FRAMES) };
if (stack_size <= 0) {
return make_failure<Backtrace_Error>(Backtrace_Unavailable {});
}
// We can't use `iterate()` here because it would inject a lamda into the call stack, so we have
// to use a normal loop
for (int i { 0 }; i < stack_size; ++i) {
::Dl_info symbol_table_entry {};
// Try to read out the symbol name from the dynamic symbol table
if (::dladdr(stack_data[i], &symbol_table_entry) == 0) {
Stack_Frame frame;
frame.function = "<unknown>";
frame.details = "Failed to read symbol";
result.push(frame);
continue;
}
// Even if ::dladdr() succeeds, we can still end up with `dli_sname == nullptr`
if (symbol_table_entry.dli_sname == nullptr) {
Stack_Frame frame;
frame.function = "<unknown>";
frame.details = "No associated symbol";
result.push(frame);
continue;
}
FFI_String<char> const mangled_symbol {
symbol_table_entry.dli_sname,
std::strlen(symbol_table_entry.dli_sname)
};
auto const handle_failure {
[&mangled_symbol](Demangle_Error const &/* error */) {
Stack_Frame frame;
frame.function = String { mangled_symbol.data(), mangled_symbol.size() };
frame.details = "Symbol demangling failed";
return frame;
}
};
auto const handle_success {
[](FFI_String<char> const &demangled_symbol) {
Stack_Frame frame;
frame.function = String { demangled_symbol.data(), demangled_symbol.size() };
return frame;
}
};
auto const frame = demangle(mangled_symbol)
.resolve(handle_failure, handle_success);
result.push(frame);
}
return make_success(std::move(result));
}
}