fix: Read Windows Version from Registry (#623)

We were previously relying on the `kernel32.dll` version, as does
Crashpad. However that version can lag behind OS releases, which can
manifest itself as failing integration tests, as the version does not
match the one returned from python `platform.version()`.
This tries to use `ntoskrnl.exe` as the kernel version, but falls back to
`kernel32.dll` as before in case that does not work.

src/sentry_os.c

@@ -1,9 +1,28 @@
 #include "sentry_os.h"
 #include "sentry_string.h"
+#include "sentry_utils.h"
 
 #ifdef SENTRY_PLATFORM_WINDOWS
 
 #    include <winver.h>
+#    define CURRENT_VERSION "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion"
+
+void *
+sentry__try_file_version(LPCWSTR filename)
+{
+
+    DWORD size = GetFileVersionInfoSizeW(filename, NULL);
+    if (!size) {
+        return NULL;
+    }
+
+    void *ffibuf = sentry_malloc(size);
+    if (!GetFileVersionInfoW(filename, 0, size, ffibuf)) {
+        sentry_free(ffibuf);
+        return NULL;
+    }
+    return ffibuf;
+}
 
 sentry_value_t
 sentry__get_os_context(void)
@@ -15,15 +34,11 @@ sentry__get_os_context(void)
 
     sentry_value_set_by_key(os, "name", sentry_value_new_string("Windows"));
 
-    void *ffibuf = NULL;
-
-    DWORD size = GetFileVersionInfoSizeW(L"kernel32.dll", NULL);
-    if (!size) {
-        goto fail;
+    void *ffibuf = sentry__try_file_version(L"ntoskrnl.exe");
+    if (!ffibuf) {
+        ffibuf = sentry__try_file_version(L"kernel32.dll");
     }
-
-    ffibuf = sentry_malloc(size);
-    if (!GetFileVersionInfoW(L"kernel32.dll", 0, size, ffibuf)) {
+    if (!ffibuf) {
         goto fail;
     }
 
@@ -34,17 +49,55 @@ sentry__get_os_context(void)
     }
     ffi->dwFileFlags &= ffi->dwFileFlagsMask;
 
+    uint32_t major_version = ffi->dwFileVersionMS >> 16;
+    uint32_t minor_version = ffi->dwFileVersionMS & 0xffff;
+    uint32_t build_version = ffi->dwFileVersionLS >> 16;
+    uint32_t ubr = ffi->dwFileVersionLS & 0xffff;
+
     char buf[32];
-    snprintf(buf, sizeof(buf), "%u.%u.%u", ffi->dwFileVersionMS >> 16,
-        ffi->dwFileVersionMS & 0xffff, ffi->dwFileVersionLS >> 16);
+    snprintf(buf, sizeof(buf), "%u.%u.%u.%lu", major_version, minor_version,
+        build_version, ubr);
+    sentry_value_set_by_key(os, "kernel_version", sentry_value_new_string(buf));
 
-    sentry_value_set_by_key(os, "version", sentry_value_new_string(buf));
+    sentry_free(ffibuf);
 
-    snprintf(buf, sizeof(buf), "%lu", ffi->dwFileVersionLS & 0xffff);
+    // The `CurrentMajorVersionNumber`, `CurrentMinorVersionNumber` and `UBR`
+    // are DWORD, while `CurrentBuild` is a SZ (text).
 
-    sentry_value_set_by_key(os, "build", sentry_value_new_string(buf));
+    uint32_t reg_version = 0;
+    DWORD buf_size = sizeof(uint32_t);
+    if (RegGetValueA(HKEY_LOCAL_MACHINE, CURRENT_VERSION,
+            "CurrentMajorVersionNumber", RRF_RT_REG_DWORD, NULL, &reg_version,
+            &buf_size)
+        == ERROR_SUCCESS) {
+        major_version = reg_version;
+    }
+    buf_size = sizeof(uint32_t);
+    if (RegGetValueA(HKEY_LOCAL_MACHINE, CURRENT_VERSION,
+            "CurrentMinorVersionNumber", RRF_RT_REG_DWORD, NULL, &reg_version,
+            &buf_size)
+        == ERROR_SUCCESS) {
+        minor_version = reg_version;
+    }
+    buf_size = sizeof(buf);
+    if (RegGetValueA(HKEY_LOCAL_MACHINE, CURRENT_VERSION, "CurrentBuild",
+            RRF_RT_REG_SZ, NULL, buf, &buf_size)
+        == ERROR_SUCCESS) {
+        build_version = (uint32_t)sentry__strtod_c(buf, NULL);
+    }
+    buf_size = sizeof(uint32_t);
+    if (RegGetValueA(HKEY_LOCAL_MACHINE, CURRENT_VERSION, "UBR",
+            RRF_RT_REG_DWORD, NULL, &reg_version, &buf_size)
+        == ERROR_SUCCESS) {
+        ubr = reg_version;
+    }
 
-    sentry_free(ffibuf);
+    snprintf(buf, sizeof(buf), "%u.%u.%u", major_version, minor_version,
+        build_version);
+    sentry_value_set_by_key(os, "version", sentry_value_new_string(buf));
+
+    snprintf(buf, sizeof(buf), "%lu", ubr);
+    sentry_value_set_by_key(os, "build", sentry_value_new_string(buf));
 
     sentry_value_freeze(os);
     return os;