Test cygwin in ci and fix support

.github/workflows/ci.yml

@@ -1022,6 +1022,30 @@ jobs:
           ninja
           ./unittest
 
+  unittest-cygwin:
+    runs-on: windows-2022
+    needs: unittest-linux
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install Cygwin
+      uses: cygwin/cygwin-install-action@v4
+      with:
+        packages: cmake gcc-g++ ninja git
+    - name: build and test
+      shell: C:\cygwin\bin\bash.exe --login -o igncr {0}
+      run: |
+        cd "$GITHUB_WORKSPACE"
+        mkdir build
+        cd build
+        cmake .. \
+          -GNinja \
+          -DCMAKE_BUILD_TYPE=Debug \
+          -DCPPTRACE_WERROR_BUILD=On \
+          -DCPPTRACE_STD_FORMAT=Off \
+          -DCPPTRACE_BUILD_TESTING=On
+        ninja
+        ./unittest.exe
+
   unittest-windows-32-bit:
     runs-on: windows-2022
     needs: unittest-windows

CMakeLists.txt

@@ -451,6 +451,10 @@ if(CPPTRACE_GET_SYMBOLS_WITH_DBGHELP)
   target_link_libraries(${target_name} PRIVATE dbghelp)
 endif()
 
+if(CYGWIN)
+  target_link_libraries(${target_name} PRIVATE kernel32)
+endif()
+
 if(CPPTRACE_GET_SYMBOLS_WITH_NOTHING)
   target_compile_definitions(${target_name} PRIVATE CPPTRACE_GET_SYMBOLS_WITH_NOTHING)
 endif()

src/binary/module_base.cpp

@@ -15,7 +15,7 @@
  #else
   #include "binary/elf.hpp"
  #endif
-#elif IS_WINDOWS
+#elif IS_WINDOWS || IS_CYGWIN
  #include "binary/pe.hpp"
 #endif
 
@@ -72,7 +72,7 @@ namespace detail {
             return it->second;
         }
     }
-    #else // Windows
+    #else // Windows / Cygwin
     Result<std::uintptr_t, internal_error> get_module_image_base(const std::string& object_path) {
         static std::mutex mutex;
         std::lock_guard<std::mutex> lock(mutex);

src/binary/object.cpp

@@ -14,10 +14,10 @@
 #if IS_LINUX || IS_APPLE
  #include <unistd.h>
  #include <dlfcn.h>
- #if IS_LINUX
+ #if IS_LINUX && (defined(CPPTRACE_HAS_DL_FIND_OBJECT) || defined(CPPTRACE_HAS_DLADDR1))
   #include <link.h> // needed for dladdr1's link_map info
  #endif
-#elif IS_WINDOWS
+#elif IS_WINDOWS || IS_CYGWIN
  #ifndef WIN32_LEAN_AND_MEAN
   #define WIN32_LEAN_AND_MEAN
  #endif

src/binary/pe.cpp

@@ -4,7 +4,7 @@
 #include "utils/error.hpp"
 #include "utils/utils.hpp"
 
-#if IS_WINDOWS
+#if IS_WINDOWS || IS_CYGWIN
 #include <array>
 #include <cstdio>
 #include <cstring>
@@ -32,11 +32,18 @@ namespace detail {
         // https://0xrick.github.io/win-internals/pe3/
         // Endianness should always be little for dos and pe headers
         std::FILE* file_ptr;
-        errno_t ret = fopen_s(&file_ptr, object_path.c_str(), "rb");
+        #ifdef __CYGWIN__
+         file_ptr = std::fopen(object_path.c_str(), "rb");
+         if(!file_ptr) {
+             return internal_error("Unable to read object file {}", object_path);
+         }
+        #else
+         errno_t ret = fopen_s(&file_ptr, object_path.c_str(), "rb");
+         if(ret != 0 || file_ptr == nullptr) {
+             return internal_error("Unable to read object file {}", object_path);
+         }
+        #endif
         auto file = raii_wrap(std::move(file_ptr), file_deleter);
-        if(ret != 0 || file == nullptr) {
-            return internal_error("Unable to read object file {}", object_path);
-        }
         auto magic = load_bytes<std::array<char, 2>>(file, 0);
         if(!magic) {
             return std::move(magic).unwrap_error();

src/binary/pe.hpp

@@ -4,7 +4,7 @@
 #include "platform/platform.hpp"
 #include "utils/utils.hpp"
 
-#if IS_WINDOWS
+#if IS_WINDOWS || IS_CYGWIN
 #include <cstdint>
 #include <string>
 

src/from_current.cpp

@@ -294,7 +294,7 @@ namespace detail {
         if(type_info_addr - page_addr + sizeof(void*) > static_cast<unsigned>(page_size)) {
             throw internal_error("pointer crosses page boundaries");
         }
-        #if IS_WINDOWS
+        #if IS_WINDOWS || IS_CYGWIN
         auto old_protections = mprotect_page_and_return_old_protections(
             reinterpret_cast<void*>(page_addr),
             page_size,

src/platform/memory_mapping.cpp

@@ -5,7 +5,7 @@
 
 #ifndef _MSC_VER
 
-#if IS_WINDOWS
+#if IS_WINDOWS || IS_CYGWIN
  #ifndef WIN32_LEAN_AND_MEAN
   #define WIN32_LEAN_AND_MEAN
  #endif
@@ -31,7 +31,10 @@
 
 CPPTRACE_BEGIN_NAMESPACE
 namespace detail {
-    #if IS_WINDOWS
+    #if IS_WINDOWS || IS_CYGWIN
+    // Cygwin uses GCC/Itanium ABI but Cygwin's mprotect seems to require 64KB-aligned addresses (allocation
+    // granularity returned by sysconf(_SC_PAGESIZE)) while we need actual page granularity for typeinfo surgery.
+    // Using the windows API here works best.
     int get_page_size() {
         SYSTEM_INFO info;
         GetSystemInfo(&info);

src/platform/memory_mapping.hpp

@@ -2,7 +2,7 @@
 
 #ifndef _MSC_VER
 
-#if IS_WINDOWS
+#if IS_WINDOWS || IS_CYGWIN
  #ifndef WIN32_LEAN_AND_MEAN
   #define WIN32_LEAN_AND_MEAN
  #endif
@@ -13,15 +13,15 @@
 
 CPPTRACE_BEGIN_NAMESPACE
 namespace detail {
-    #if IS_WINDOWS
+    #if IS_WINDOWS || IS_CYGWIN
      constexpr auto memory_readonly = PAGE_READONLY;
      constexpr auto memory_readwrite = PAGE_READWRITE;
     #else
      constexpr auto memory_readonly = PROT_READ;
      constexpr auto memory_readwrite = PROT_READ | PROT_WRITE;
     #endif
     int get_page_size();
-    #if !IS_WINDOWS
+    #if !IS_WINDOWS && !IS_CYGWIN
      int get_page_protections(void* page);
     #endif
     int mprotect_page_and_return_old_protections(void* page, int page_size, int protections);

src/platform/platform.hpp

@@ -4,10 +4,14 @@
 #define IS_WINDOWS 0
 #define IS_LINUX 0
 #define IS_APPLE 0
+#define IS_CYGWIN 0
 
 #if defined(_WIN32)
  #undef IS_WINDOWS
  #define IS_WINDOWS 1
+#elif defined(__CYGWIN__)
+ #undef IS_CYGWIN
+ #define IS_CYGWIN 1
 #elif defined(__linux) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
  #undef IS_LINUX
  #define IS_LINUX 1

src/platform/program_name.hpp

@@ -66,7 +66,7 @@ namespace detail {
 }
 CPPTRACE_END_NAMESPACE
 
-#elif IS_LINUX
+#elif IS_LINUX || IS_CYGWIN
 
 #include <sys/types.h>
 #include <unistd.h>

src/symbols/symbols_with_addr2line.cpp

@@ -15,7 +15,7 @@
 #include <utility>
 #include <vector>
 
-#if IS_LINUX || IS_APPLE
+#if IS_LINUX || IS_APPLE || IS_CYGWIN
  #include <unistd.h>
  #include <sys/types.h>
  #include <sys/wait.h>
@@ -27,7 +27,7 @@
 CPPTRACE_BEGIN_NAMESPACE
 namespace detail {
 namespace addr2line {
-    #if IS_LINUX || IS_APPLE
+    #if IS_LINUX || IS_APPLE || IS_CYGWIN
     bool has_addr2line() {
         static std::mutex mutex;
         static bool has_addr2line = false;