Filza 27.2 worse_query: public and developer builds

XPF/external/ChOma/src/Host.c

@@ -0,0 +1,89 @@
+#include "Host.h"
+
+#include "MachO.h"
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <mach/machine.h>
+#include <sys/utsname.h>
+
+int host_get_cpu_information(cpu_type_t *cputype, cpu_subtype_t *cpusubtype)
+{
+    size_t len;
+    
+    // Query for cputype
+    len = sizeof(cputype);
+    if (sysctlbyname("hw.cputype", cputype, &len, NULL, 0) == -1) { printf("Error: no cputype.\n"); return -1; }
+    
+    // Query for cpusubtype
+    len = sizeof(cpusubtype);
+    if (sysctlbyname("hw.cpusubtype", cpusubtype, &len, NULL, 0) == -1) { printf("Error: no cpusubtype.\n"); return -1; }
+    
+    return 0;
+}
+
+int host_supported_arm64e_abi(void)
+{
+    struct utsname name;
+    if (uname(&name) != 0) return -1;
+    if (strcmp(name.release, "20.0.0") >= 0) {
+        // iOS 14+, macOS 11+ use new ABI
+        return 2;
+    }
+    else {
+        // iOS 12-13 use old ABI
+        return 1;
+    }
+}
+
+MachO *fat_find_preferred_slice(Fat *fat)
+{
+    cpu_type_t cputype;
+    cpu_subtype_t cpusubtype;
+    if (host_get_cpu_information(&cputype, &cpusubtype) != 0) { return NULL; }
+
+    MachO *preferredMacho = NULL;
+
+    // If you intend on supporting non darwin, implement platform specific logic here using #ifdef's
+    if (cputype == CPU_TYPE_ARM64) {
+        if (cpusubtype == CPU_SUBTYPE_ARM64E) {
+            // If this is an arm64e device, first try to find a new ABI arm64e slice
+            int supportedArm64eABI = host_supported_arm64e_abi();
+            if (supportedArm64eABI != -1) {
+                if (supportedArm64eABI == 2) {
+                    // Find new ABI slice if host supports it
+                    preferredMacho = fat_find_slice(fat, cputype, (CPU_SUBTYPE_ARM64E | CPU_SUBTYPE_ARM64E_ABI_V2));
+                }
+                if (!preferredMacho) {
+                    // If no new ABI slice is found or the host does not support it, try to find an old ABI arm64e slice
+                    preferredMacho = fat_find_slice(fat, cputype, CPU_SUBTYPE_ARM64E);
+                    if (preferredMacho) {
+                        if (macho_get_filetype(preferredMacho) == MH_EXECUTE && supportedArm64eABI == 2) {
+                            // If this is an old ABI binary trying to run on a new ABI system, discard it
+                            // If it's an old ABI *library* trying to be loaded on a new ABI system, use it
+                            preferredMacho = NULL;
+                        }
+                    }
+                }
+            }
+        }
+
+        if (!preferredMacho) {
+            // If not arm64e device or no arm64e slice found, try to find regular arm64 slice
+
+            // The Kernel prefers an arm64v8 slice to an arm64 slice, so check that first
+            // On iOS <14, dyld does not support arm64v8 slices, but that doesn't matter as the Kernel will still try to spawn it
+            preferredMacho = fat_find_slice(fat, cputype, CPU_SUBTYPE_ARM64_V8);
+            if (!preferredMacho) {
+                // If that's not found, finally check for a regular arm64 slice
+                preferredMacho = fat_find_slice(fat, cputype, CPU_SUBTYPE_ARM64_ALL);
+            }
+        }
+    }
+
+    if (!preferredMacho) {
+        printf("Error: failed to find a preferred MachO slice that matches the host architecture.\n");
+    }
+    return preferredMacho;
+}