Merge pull request #118 from dlfcn-win32/variousimprovements2025HEADmaster

Remove use of CRT, fix gcc compilation in C++ mode, fix missing includes and fix warnings

4 files changed, 91 insertions, 53 deletions

diff --git a/src/dlfcn.c b/src/dlfcn.c
index cb9f9bb..1830b20 100644
--- a/src/dlfcn.c
+++ b/src/dlfcn.c
@@ -26,12 +26,10 @@
 

 #ifdef _DEBUG

 #define _CRTDBG_MAP_ALLOC

-#include <stdlib.h>

+#include <stdlib.h> /* malloc() and free() */

 #include <crtdbg.h>

 #endif

 #include <windows.h>

-#include <stdio.h>

-#include <stdlib.h>

 

 /* Older versions do not have this type */

 #if _WIN32_WINNT < 0x0500

@@ -61,7 +59,12 @@ typedef ULONG ULONG_PTR;
 

 #ifdef _MSC_VER

 #if _MSC_VER >= 1000

-/* https://docs.microsoft.com/en-us/cpp/intrinsics/returnaddress */

+/* https://docs.microsoft.com/en-us/cpp/intrinsics/returnaddress

+ * When compiling in C++ mode, it is required to have C declaration for _ReturnAddress.

+ */

+#ifdef __cplusplus

+extern "C" void *_ReturnAddress(void);

+#endif

 #pragma intrinsic( _ReturnAddress )

 #else

 /* On older version read return address from the value on stack pointer + 4 of

@@ -70,7 +73,11 @@ typedef ULONG ULONG_PTR;
  * EBP register optimization. Read value of EBP + 4 via inline assembly. And

  * because inline assembly does not have a return value, put it into naked

  * function which does not have prologue and epilogue and preserve registers.

+ * When compiling in C++ mode, it is required to have C declaration for _alloca.

  */

+#ifdef __cplusplus

+extern "C" void *__cdecl _alloca(size_t);

+#endif

 __declspec( naked ) static void *_ReturnAddress( void ) { __asm mov eax, [ebp+4] __asm ret }

 #define _ReturnAddress( ) ( _alloca(1), _ReturnAddress( ) )

 #endif

@@ -96,6 +103,24 @@ __declspec( naked ) static void *_ReturnAddress( void ) { __asm mov eax, [ebp+4]
 #define DLFCN_NOINLINE

 #endif

 

+static void *MyAlloc( size_t size )

+{

+#ifdef _DEBUG

+    return malloc( size );

+#else

+    return LocalAlloc( LPTR, size );

+#endif

+}

+

+static void MyFree( void *ptr )

+{

+#ifdef _DEBUG

+    free( ptr );

+#else

+    LocalFree( ptr );

+#endif

+}

+

 /* Note:

  * MSDN says these functions are not thread-safe. We make no efforts to have

  * any kind of thread safety.

@@ -140,7 +165,7 @@ static BOOL local_add( HMODULE hModule )
 

     for( pobject = &first_object; pobject->next; pobject = pobject->next );

 

-    nobject = (local_object *) malloc( sizeof( local_object ) );

+    nobject = (local_object *) MyAlloc( sizeof( local_object ) );

 

     if( !nobject )

         return FALSE;

@@ -170,7 +195,7 @@ static void local_rem( HMODULE hModule )
     if( pobject->previous )

         pobject->previous->next = pobject->next;

 

-    free( pobject );

+    MyFree( pobject );

 }

 

 /* POSIX says dlerror( ) doesn't have to be thread-safe, so we use one

@@ -184,19 +209,15 @@ static BOOL error_occurred;
 static void save_err_str( const char *str, DWORD dwMessageId )

 {

     DWORD ret;

-    size_t pos, len;

-

-    len = strlen( str );

-    if( len > sizeof( error_buffer ) - 5 )

-        len = sizeof( error_buffer ) - 5;

+    size_t pos, i;

 

     /* Format error message to:

      * "<argument to function that failed>": <Windows localized error message>

       */

     pos = 0;

     error_buffer[pos++] = '"';

-    memcpy( error_buffer + pos, str, len );

-    pos += len;

+    for( i = 0; i < sizeof( error_buffer ) - 5 && str[i] != '\0'; i++ )

+        error_buffer[pos++] = str[i];

     error_buffer[pos++] = '"';

     error_buffer[pos++] = ':';

     error_buffer[pos++] = ' ';

@@ -233,7 +254,7 @@ static void save_err_ptr_str( const void *ptr, DWORD dwMessageId )
     for( i = 0; i < 2 * sizeof( ptr ); i++ )

     {

         num = (char) ( ( ( (ULONG_PTR) ptr ) >> ( 8 * sizeof( ptr ) - 4 * ( i + 1 ) ) ) & 0xF );

-        ptr_buf[2 + i] = num + ( ( num < 0xA ) ? '0' : ( 'A' - 0xA ) );

+        ptr_buf[2 + i] = (char) ( num + ( ( num < 0xA ) ? '0' : ( 'A' - 0xA ) ) );

     }

 

     ptr_buf[2 + 2 * sizeof( ptr )] = 0;

@@ -252,7 +273,7 @@ static UINT MySetErrorMode( UINT uMode )
     {

         kernel32 = GetModuleHandleA( "Kernel32.dll" );

         if( kernel32 != NULL )

-            SetThreadErrorModePtr = (BOOL (WINAPI *)(DWORD, DWORD *)) (LPVOID) GetProcAddress( kernel32, "SetThreadErrorMode" );

+            SetThreadErrorModePtr = (BOOL (WINAPI *)(DWORD, DWORD *)) (void(*)(void)) GetProcAddress( kernel32, "SetThreadErrorMode" );

         if( SetThreadErrorModePtr == NULL )

             failed = TRUE;

     }

@@ -283,7 +304,7 @@ static HMODULE MyGetModuleHandleFromAddress( const void *addr )
     {

         kernel32 = GetModuleHandleA( "Kernel32.dll" );

         if( kernel32 != NULL )

-            GetModuleHandleExAPtr = (BOOL (WINAPI *)(DWORD, LPCSTR, HMODULE *)) (LPVOID) GetProcAddress( kernel32, "GetModuleHandleExA" );

+            GetModuleHandleExAPtr = (BOOL (WINAPI *)(DWORD, LPCSTR, HMODULE *)) (void(*)(void)) GetProcAddress( kernel32, "GetModuleHandleExA" );

         if( GetModuleHandleExAPtr == NULL )

             failed = TRUE;

     }

@@ -291,7 +312,7 @@ static HMODULE MyGetModuleHandleFromAddress( const void *addr )
     if( !failed )

     {

         /* If GetModuleHandleExA is available use it with GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS */

-        if( !GetModuleHandleExAPtr( GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, addr, &hModule ) )

+        if( !GetModuleHandleExAPtr( GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, (LPCSTR) addr, &hModule ) )

             return NULL;

     }

     else

@@ -314,6 +335,7 @@ static BOOL MyEnumProcessModules( HANDLE hProcess, HMODULE *lphModule, DWORD cb,
     static BOOL (WINAPI *EnumProcessModulesPtr)(HANDLE, HMODULE *, DWORD, LPDWORD) = NULL;

     static BOOL failed = FALSE;

     UINT uMode;

+    HMODULE kernel32;

     HMODULE psapi;

 

     if( failed )

@@ -322,9 +344,9 @@ static BOOL MyEnumProcessModules( HANDLE hProcess, HMODULE *lphModule, DWORD cb,
     if( EnumProcessModulesPtr == NULL )

     {

         /* Windows 7 and newer versions have K32EnumProcessModules in Kernel32.dll which is always pre-loaded */

-        psapi = GetModuleHandleA( "Kernel32.dll" );

-        if( psapi != NULL )

-            EnumProcessModulesPtr = (BOOL (WINAPI *)(HANDLE, HMODULE *, DWORD, LPDWORD)) (LPVOID) GetProcAddress( psapi, "K32EnumProcessModules" );

+        kernel32 = GetModuleHandleA( "Kernel32.dll" );

+        if( kernel32 != NULL )

+            EnumProcessModulesPtr = (BOOL (WINAPI *)(HANDLE, HMODULE *, DWORD, LPDWORD)) (void(*)(void)) GetProcAddress( kernel32, "K32EnumProcessModules" );

 

         /* Windows Vista and older version have EnumProcessModules in Psapi.dll which needs to be loaded */

         if( EnumProcessModulesPtr == NULL )

@@ -332,13 +354,13 @@ static BOOL MyEnumProcessModules( HANDLE hProcess, HMODULE *lphModule, DWORD cb,
             /* Do not let Windows display the critical-error-handler message box */

             uMode = MySetErrorMode( SEM_FAILCRITICALERRORS );

             psapi = LoadLibraryA( "Psapi.dll" );

+            MySetErrorMode( uMode );

             if( psapi != NULL )

             {

-                EnumProcessModulesPtr = (BOOL (WINAPI *)(HANDLE, HMODULE *, DWORD, LPDWORD)) (LPVOID) GetProcAddress( psapi, "EnumProcessModules" );

+                EnumProcessModulesPtr = (BOOL (WINAPI *)(HANDLE, HMODULE *, DWORD, LPDWORD)) (void(*)(void)) GetProcAddress( psapi, "EnumProcessModules" );

                 if( EnumProcessModulesPtr == NULL )

                     FreeLibrary( psapi );

             }

-            MySetErrorMode( uMode );

         }

 

         if( EnumProcessModulesPtr == NULL )

@@ -368,13 +390,13 @@ void *dlopen( const char *file, int mode )
          * symbol object must be provided. That object must be able to access

          * all symbols from the original program file, and any objects loaded

          * with the RTLD_GLOBAL flag.

-         * The return value from GetModuleHandle( ) allows us to retrieve

+         * The return value from GetModuleHandleA( ) allows us to retrieve

          * symbols only from the original program file. EnumProcessModules() is

          * used to access symbols from other libraries. For objects loaded

          * with the RTLD_LOCAL flag, we create our own list later on. They are

          * excluded from EnumProcessModules() iteration.

          */

-        hModule = GetModuleHandle( NULL );

+        hModule = GetModuleHandleA( NULL );

 

         if( !hModule )

             save_err_str( "(null)", GetLastError( ) );

@@ -386,7 +408,11 @@ void *dlopen( const char *file, int mode )
         char lpFileName[MAX_PATH];

         size_t i, len;

 

-        len = strlen( file );

+        for( len = 0; ; len++ )

+        {

+            if( file[len] == '\0' )

+                break;

+        }

 

         if( len >= sizeof( lpFileName ) )

         {

@@ -466,6 +492,10 @@ int dlclose( void *handle )
 

     error_occurred = FALSE;

 

+    /* dlopen(NULL, ...) does not call LoadLibrary(), so do not call FreeLibrary(). */

+    if( hModule == GetModuleHandleA( NULL ) )

+        return 0;

+

     ret = FreeLibrary( hModule );

 

     /* If the object was loaded with RTLD_LOCAL, remove it from list of local

@@ -495,7 +525,7 @@ void *dlsym( void *handle, const char *name )
 

     symbol = NULL;

     hCaller = NULL;

-    hModule = GetModuleHandle( NULL );

+    hModule = GetModuleHandleA( NULL );

     dwMessageId = 0;

 

     if( handle == RTLD_DEFAULT )

@@ -548,13 +578,13 @@ void *dlsym( void *handle, const char *name )
 

         hCurrentProc = GetCurrentProcess( );

 

-        /* GetModuleHandle( NULL ) only returns the current program file. So

+        /* GetModuleHandleA( NULL ) only returns the current program file. So

          * if we want to get ALL loaded module including those in linked DLLs,

          * we have to use EnumProcessModules( ).

          */

         if( MyEnumProcessModules( hCurrentProc, NULL, 0, &dwSize ) != 0 )

         {

-            modules = malloc( dwSize );

+            modules = (HMODULE *) MyAlloc( dwSize );

             if( modules )

             {

                 if( MyEnumProcessModules( hCurrentProc, modules, dwSize, &cbNeeded ) != 0 && dwSize == cbNeeded )

@@ -573,13 +603,13 @@ void *dlsym( void *handle, const char *name )
                         symbol = GetProcAddress( modules[i], name );

                         if( symbol != NULL )

                         {

-                            free( modules );

+                            MyFree( modules );

                             goto end;

                         }

                     }

 

                 }

-                free( modules );

+                MyFree( modules );

             }

             else

             {

@@ -640,7 +670,7 @@ static BOOL get_image_section( HMODULE module, int index, void **ptr, DWORD *siz
     if( optionalHeader->Magic != IMAGE_NT_OPTIONAL_HDR_MAGIC )

         return FALSE;

 

-    if( index < 0 || index >= IMAGE_NUMBEROF_DIRECTORY_ENTRIES || index >= optionalHeader->NumberOfRvaAndSizes )

+    if( index < 0 || index >= IMAGE_NUMBEROF_DIRECTORY_ENTRIES || (DWORD)index >= optionalHeader->NumberOfRvaAndSizes )

         return FALSE;

 

     if( optionalHeader->DataDirectory[index].Size == 0 || optionalHeader->DataDirectory[index].VirtualAddress == 0 )

@@ -699,18 +729,18 @@ static BOOL is_valid_address( const void *addr )
     /* check valid pointer */

     result = VirtualQuery( addr, &info, sizeof( info ) );

 

-    if( result == 0 || info.AllocationBase == NULL || info.AllocationProtect == 0 || info.AllocationProtect == PAGE_NOACCESS )

+    if( result != sizeof( info ) || info.AllocationBase == NULL || info.State == MEM_FREE || info.State == MEM_RESERVE || info.Protect == 0 || info.Protect == PAGE_NOACCESS )

         return FALSE;

 

     return TRUE;

 }

 

 #if defined(_M_ARM64) || defined(__aarch64__)

-static INT64 sign_extend(UINT64 value, UINT bits)

+static INT64 sign_extend( UINT64 value, UINT bits )

 {

     const UINT left = 64 - bits;

     const INT64 m1 = -1;

-    const INT64 wide = (INT64) (value << left);

+    const INT64 wide = (INT64) ( value << left );

     const INT64 sign = ( wide < 0 ) ? ( m1 << left ) : 0;

 

     return value | sign;

@@ -742,16 +772,18 @@ static INT64 sign_extend(UINT64 value, UINT bits)
 static BOOL is_import_thunk( const void *addr )

 {

 #if defined(_M_ARM64) || defined(__aarch64__)

-    ULONG opCode1 = * (ULONG *) ( (BYTE *) addr );

-    ULONG opCode2 = * (ULONG *) ( (BYTE *) addr + 4 );

-    ULONG opCode3 = * (ULONG *) ( (BYTE *) addr + 8 );

+    ULONG opCode1 = *(ULONG *) ( (BYTE *) addr );

+    ULONG opCode2 = *(ULONG *) ( (BYTE *) addr + 4 );

+    ULONG opCode3 = *(ULONG *) ( (BYTE *) addr + 8 );

 

-    return (opCode1 & 0x9f00001f) == 0x90000010    /* adrp x16, [page_offset] */

-        && (opCode2 & 0xffe003ff) == 0xf9400210    /* ldr  x16, [x16, offset] */

+    return ( opCode1 & 0x9f00001f ) == 0x90000010  /* adrp x16, [page_offset] */

+        && ( opCode2 & 0xffe003ff ) == 0xf9400210  /* ldr  x16, [x16, offset] */

         && opCode3 == 0xd61f0200                   /* br   x16 */

         ? TRUE : FALSE;

+#elif defined(_M_AMD64) || defined(_M_IX86) || defined(__x86_64__) || defined(__i386__)

+    return *(USHORT *) addr == 0x25ff ? TRUE : FALSE;

 #else

-    return *(short *) addr == 0x25ff ? TRUE : FALSE;

+    return FALSE;

 #endif

 }

 

@@ -768,24 +800,24 @@ static void *get_address_from_import_address_table( void *iat, DWORD iat_size, c
      *  0x7ff772ae78c4 <+25764>: ldr    x16, [x16, #0xdc0]

      *  0x7ff772ae78c8 <+25768>: br     x16

      */

-    ULONG opCode1 = * (ULONG *) ( (BYTE *) addr );

-    ULONG opCode2 = * (ULONG *) ( (BYTE *) addr + 4 );

+    ULONG opCode1 = *(ULONG *) ( (BYTE *) addr );

+    ULONG opCode2 = *(ULONG *) ( (BYTE *) addr + 4 );

 

     /* Extract the offset from adrp instruction */

-    UINT64 pageLow2 = (opCode1 >> 29) & 3;

-    UINT64 pageHigh19 = (opCode1 >> 5) & ~(~0ull << 19);

-    INT64 page = sign_extend((pageHigh19 << 2) | pageLow2, 21) << 12;

+    UINT64 pageLow2 = ( opCode1 >> 29 ) & 3;

+    UINT64 pageHigh19 = ( opCode1 >> 5 ) & ~( ~0ull << 19 );

+    INT64 page = sign_extend( ( pageHigh19 << 2 ) | pageLow2, 21 ) << 12;

 

     /* Extract the offset from ldr instruction */

-    UINT64 offset = ((opCode2 >> 10) & ~(~0ull << 12)) << 3;

+    UINT64 offset = ( ( opCode2 >> 10 ) & ~( ~0ull << 12 ) ) << 3;

 

     /* Calculate the final address */

     BYTE *ptr = (BYTE *) ( (ULONG64) thkp & ~0xfffull ) + page + offset;

-#else

+#elif defined(_M_AMD64) || defined(_M_IX86) || defined(__x86_64__) || defined(__i386__)

     /* Get offset from thunk table (after instruction 0xff 0x25)

      *   4018c8 <_VirtualQuery>: ff 25 4a 8a 00 00

      */

-    ULONG offset = *(ULONG *)( thkp + 2 );

+    ULONG offset = *(ULONG *) ( thkp + 2 );

 #if defined(_M_AMD64) || defined(__x86_64__)

     /* On 64 bit the offset is relative

      *      4018c8:   ff 25 4a 8a 00 00    jmpq    *0x8a4a(%rip)    # 40a318 <__imp_VirtualQuery>

@@ -793,13 +825,15 @@ static void *get_address_from_import_address_table( void *iat, DWORD iat_size, c
      *   100002f20:   ff 25 3a e1 ff ff    jmpq   *-0x1ec6(%rip)    # 0x100001060

      * So cast to signed LONG type

      */

-    BYTE *ptr = (BYTE *)( thkp + 6 + (LONG) offset );

+    BYTE *ptr = (BYTE *) ( thkp + 6 + (LONG) offset );

 #else

     /* On 32 bit the offset is absolute

      *   4019b4:    ff 25 90 71 40 00    jmp    *0x40719

      */

     BYTE *ptr = (BYTE *) offset;

 #endif

+#else

+    return NULL;

 #endif

 

     if( !is_valid_address( ptr ) || ptr < (BYTE *) iat || ptr > (BYTE *) iat + iat_size )

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index cd321f2..1fe7387 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -31,6 +31,4 @@ if(WIN32 AND NOT BUILD_SHARED_LIBS)
     endif()
 endif()
 
-install(TARGETS test-dladdr EXPORT dlfcn-win32-targets RUNTIME DESTINATION bin)
-
 add_test(NAME test-dladdr COMMAND test-dladdr WORKING_DIRECTORY $<TARGET_FILE_DIR:test-dladdr>)
diff --git a/tests/test-dladdr.c b/tests/test-dladdr.c
index 5568f23..aa815b0 100644
--- a/tests/test-dladdr.c
+++ b/tests/test-dladdr.c
@@ -140,6 +140,7 @@ __declspec(dllexport)
 #endif
 int main(int argc, char **argv)
 {
+#ifdef _WIN32
 #if defined(_M_ARM64) || defined(__aarch64__)
     /* points to non reachable address */
     unsigned char zero_thunk_address[12] = { 0x10, 0x00, 0x00, 0x90, 0x10, 0x02, 0x40, 0xF9, 0x00, 0x02, 0x1F, 0xD6 };
@@ -147,13 +148,16 @@ int main(int argc, char **argv)
     unsigned char invalid_thunk_address[12] = { 0x10, 0x00, 0x00, 0xb0, 0x10, 0x06, 0x47, 0xF9, 0x00, 0x02, 0x1F, 0xD6 };
     /* no import thunk */
     unsigned char no_import_thunk[12] = { 0x11, 0x00, 0x00, 0xb0, 0x31, 0x06, 0x47, 0xF9, 0x20, 0x02, 0x1F, 0xD6 };
-#else
+#elif defined(_M_AMD64) || defined(_M_IX86) || defined(__x86_64__) || defined(__i386__)
     /* points to non reachable address */
     unsigned char zero_thunk_address[6] = { 0xFF, 0x25, 0x00, 0x00, 0x00, 0x00 };
     /* points to executable base */
     unsigned char invalid_thunk_address[6] = { 0xFF, 0x25, 0x00, 0x00, 0x40, 0x00 };
     /* no import thunk */
     unsigned char no_import_thunk[6] = { 0xFF, 0x26, 0x00, 0x00, 0x40, 0x00 };
+#else
+#error "thunk test cases are not defined for this architecture"
+#endif
 #endif
     int  result = 0;
     UNUSED(argv);
@@ -169,11 +173,12 @@ int main(int argc, char **argv)
     result |= check_dladdr( "function from executable", (void*)main, "main", Pass );
     result |= check_dladdr( "static function from executable", (void*)print_dl_info, "print_dl_info", Fail );
     result |= check_dladdr( "address with positive offset", ((char*)atoi)+1, "atoi", PassWithDifferentAddress );
+
+#ifdef _WIN32
     result |= check_dladdr( "zero address from import thunk", zero_thunk_address, "", NoInfo );
     result |= check_dladdr( "invalid address from import thunk", invalid_thunk_address, "", NoInfo );
     result |= check_dladdr( "no import thunk", no_import_thunk, "", NoInfo );
 
-#ifdef _WIN32
     result |= check_dladdr( "last entry in iat", (void*)VirtualQuery, "VirtualQuery", PassWithDifferentAddress );
 
     result |= check_dladdr ( "address through import thunk", (void*)GetModuleHandleA, "GetModuleHandleA", PassWithDifferentAddress );
diff --git a/tests/test.c b/tests/test.c
index 1d0d437..4fa7089 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -36,6 +36,7 @@
 #include <io.h>

 #include <fcntl.h>

 #include <direct.h>

+#include <errno.h>

 #include "dlfcn.h"

 

 /* If these dlclose's fails, we don't care as the handles are going to be