Check linker compatibility directly from HMODULE

Checking the linker compatibility with extranous `ImageLoad()` calls is
possible, but unnecessary, since the modules are either already loaded
or loaded shortly afterwards, so that we can get the required
information directly from the module handles.  And actually, doing
`ImageLoad()` as well as `LoadLibrary()` leaves a tiny room for a race
condition, because both functions will lookup the module in the search
path, so there is no *guarantee* that both are dealing with the same
module.  Dropping the `ImageLoad()` calls also has the advantage to no
longer face the issue reported in bug #79557.  A very minor additional
advantage is that we no longer have to link against Imagehlp.dll.

Furthermore, there is no need to check for CRT compatibility multiple
times, so we can simplify the signature of `php_win32_crt_compatible`,
and at the same time clean up main.c a bit.

These changes require to change the signature of the exported
`php_win32_image_compatible` and `php_win32_crt_compatible` functions,
which now expect a `HMODULE` and nothing, respectively, instead of the
module name.

1 files changed, 30 insertions, 28 deletions

diff --git a/win32/winutil.c b/win32/winutil.c
index 40664a9e03..530dc4f0f6 100644
--- a/win32/winutil.c
+++ b/win32/winutil.c
@@ -20,7 +20,6 @@
 #include "codepage.h"
 #include <bcrypt.h>
 #include <lmcons.h>
-#include <imagehlp.h>
 
 
 PHP_WINUTIL_API char *php_win32_error_to_msg(HRESULT error)
@@ -436,26 +435,13 @@ PHP_WINUTIL_API char *php_win32_get_username(void)
 	return uname;
 }/*}}}*/
 
-static zend_always_inline BOOL is_compatible(const char *name, BOOL is_smaller, char *format, char **err)
+static zend_always_inline BOOL is_compatible(HMODULE handle, BOOL is_smaller, char *format, char **err)
 {/*{{{*/
-	/* work around ImageLoad() issue */
-	const char *name_stripped = name;
-	if (name[0] == '.' && IS_SLASH(name[1])) {
-		name_stripped += 2;
-	}
-
-	PLOADED_IMAGE img = ImageLoad(name_stripped, NULL);
+	PIMAGE_DOS_HEADER dosHeader = (PIMAGE_DOS_HEADER) handle;
+	PIMAGE_NT_HEADERS pNTHeader = (PIMAGE_NT_HEADERS)((char *) dosHeader + dosHeader->e_lfanew);
 
-	if (!img) {
-		DWORD _err = GetLastError();
-		char *err_txt = php_win32_error_to_msg(_err);
-		spprintf(err, 0, "Failed to load %s, %s", name, err_txt);
-		free(err_txt);
-		return FALSE;
-	}
-
-	DWORD major = img->FileHeader->OptionalHeader.MajorLinkerVersion;
-	DWORD minor = img->FileHeader->OptionalHeader.MinorLinkerVersion;
+	DWORD major = pNTHeader->OptionalHeader.MajorLinkerVersion;
+	DWORD minor = pNTHeader->OptionalHeader.MinorLinkerVersion;
 
 #if PHP_LINKER_MAJOR == 14
 	/* VS 2015, 2017 and 2019 are binary compatible, but only forward compatible.
@@ -474,23 +460,39 @@ static zend_always_inline BOOL is_compatible(const char *name, BOOL is_smaller,
 	if (PHP_LINKER_MAJOR != major)
 #endif
 	{
-		spprintf(err, 0, format, name, major, minor, PHP_LINKER_MAJOR, PHP_LINKER_MINOR);
-		ImageUnload(img);
+		char buf[MAX_PATH];
+		if (GetModuleFileName(handle, buf, sizeof(buf)) != 0) {
+			spprintf(err, 0, format, buf, major, minor, PHP_LINKER_MAJOR, PHP_LINKER_MINOR);
+		} else {
+			spprintf(err, 0, "Can't retrieve the module name (error %u)", GetLastError());
+		}
 		return FALSE;
 	}
-	ImageUnload(img);
 
 	return TRUE;
 }/*}}}*/
 
-PHP_WINUTIL_API BOOL php_win32_image_compatible(const char *name, char **err)
+PHP_WINUTIL_API BOOL php_win32_image_compatible(HMODULE handle, char **err)
 {/*{{{*/
-	return is_compatible(name, TRUE, "Can't load module '%s' as it's linked with %u.%u, but the core is linked with %d.%d", err);
+	return is_compatible(handle, TRUE, "Can't load module '%s' as it's linked with %u.%u, but the core is linked with %d.%d", err);
 }/*}}}*/
 
-/* Expect a CRT name DLL. */
-PHP_WINUTIL_API BOOL php_win32_crt_compatible(const char *name, char **err)
+/* Expect a CRT module handle */
+PHP_WINUTIL_API BOOL php_win32_crt_compatible(char **err)
 {/*{{{*/
-	return is_compatible(name, FALSE, "'%s' %u.%u is not compatible with this PHP build linked with %d.%d", err);
+#if PHP_LINKER_MAJOR == 14
+	/* Extend for other CRT if needed. */
+# if PHP_DEBUG
+	const char *crt_name = "vcruntime140d.dll";
+# else
+	const char *crt_name = "vcruntime140.dll";
+# endif
+	HMODULE handle = GetModuleHandle(crt_name);
+	if (handle == NULL) {
+		spprintf(err, 0, "Can't get handle of module %s (error %u)", crt_name, GetLastError());
+		return FALSE;
+	}
+	return is_compatible(handle, FALSE, "'%s' %u.%u is not compatible with this PHP build linked with %d.%d", err);
+#endif
+	return TRUE;
 }/*}}}*/
-