_availability_version_check hook

palera1n · Feb 4, 2024 · e383764 · e383764
1 parent f5d5483
commit e383764
Showing 1 changed file with 94 additions and 0 deletions.
diff --git a/src/systemhook/main.c b/src/systemhook/main.c
@@ -593,6 +593,97 @@ int reboot3_hook(uint64_t howto, ...)
 	return 0;
 }
 
+typedef struct {
+    uint32_t platform;
+    uint32_t version;
+} DyldBuildVersion;
+
+__API_AVAILABLE(macos(10.14), ios(12.0), tvos(12.0), bridgeos(3.0))
+uint32_t dyld_get_active_platform(void);
+
+#define CONSTRUCT_V(major, minor, subminor) ((major & 0xffff) << 16) | ((minor & 0xff) << 8) | (subminor & 0xff)
+
+__API_AVAILABLE(macos(10.15), ios(13.0), tvos(13.0), bridgeos(4.0))
+bool _availability_version_check(uint32_t count, DyldBuildVersion versions[]);
+
+// this hook is used to make __builtin_available work normally in platform mismatched binaries
+__API_AVAILABLE(macos(10.15), ios(13.0), tvos(13.0), bridgeos(4.0))
+bool _availability_version_check_hook(uint32_t count, DyldBuildVersion versions[]) {
+    uint32_t current_plat = dyld_get_active_platform();
+    for (int i = 0; i < count; i++) {
+        DyldBuildVersion* version = &versions[i];
+        if (current_plat == version->platform) continue;
+        uint32_t major = (version->version >> 16) & 0xffff;
+        uint32_t minor = (version->version >> 8) & 0xff;
+        uint32_t subminor = version->version & 0xff;
+        switch (current_plat) {
+            case PLATFORM_IOS:
+            case PLATFORM_TVOS:
+                switch (version->platform) {
+                    case PLATFORM_MACOS:
+                        if (major == 10) {
+                            major = minor - 2;
+                            minor = subminor;
+                            subminor = 0;
+                        } else if (major > 10) major += 3;
+                        else major = 2;
+                        break;
+                    case PLATFORM_BRIDGEOS:
+                        major += 9;
+                        break;
+                    case PLATFORM_WATCHOSSIMULATOR:
+                        major += 7;
+                        break;
+                    case PLATFORM_VISIONOS:
+                    case PLATFORM_VISIONOSSIMULATOR:
+                        major += 16;
+                        break;
+                    default:
+                        break;
+                }
+                break;
+            case PLATFORM_BRIDGEOS:
+                switch (version->platform) {
+                    case PLATFORM_MACOS:
+                        if (major == 10) {
+                            major = minor - 11;
+                            minor = subminor;
+                            subminor = 0;
+                        } else if (major > 10) major -= 6;
+                        else major = 2;
+                        break;
+                    case PLATFORM_IOS:
+                    case PLATFORM_TVOS:
+                    case PLATFORM_IOSSIMULATOR:
+                    case PLATFORM_TVOSSIMULATOR:
+                        major -= 9;
+                        break;
+                    case PLATFORM_WATCHOSSIMULATOR:
+                        major -= 2;
+                        break;
+                    case PLATFORM_VISIONOS:
+                    case PLATFORM_VISIONOSSIMULATOR:
+                        major += 7;
+                        break;
+                    default:
+                        break;
+                }
+                break;
+            default:
+                break;
+        }
+        version->version = CONSTRUCT_V(major, minor, subminor);
+        version->platform = current_plat;
+    }
+    if (!_availability_version_check) {
+        fprintf(stderr, "_availability_version_check unavailable\n");
+        return false;
+    }
+    bool retval = _availability_version_check(count, versions);
+    return retval;
+}
+
+
 DYLD_INTERPOSE(posix_spawn_hook, posix_spawn)
 DYLD_INTERPOSE(posix_spawnp_hook, posix_spawnp)
 DYLD_INTERPOSE(execve_hook, execve)
@@ -615,3 +706,6 @@ DYLD_INTERPOSE(vfork_hook, vfork)
 DYLD_INTERPOSE(forkpty_hook, forkpty)
 DYLD_INTERPOSE(daemon_hook, daemon)
 DYLD_INTERPOSE(reboot3_hook, reboot3)
+
+__API_AVAILABLE(macos(10.15), ios(13.0), tvos(13.0), bridgeos(4.0))
+DYLD_INTERPOSE(_availability_version_check_hook, _availability_version_check)