Make it possible to update old filesystems to ODR APK

mkdir -p /ish/apk && \
echo 'file:///ish/apk/main' > /etc/apk/repositories && \
mount -t apk apk /ish/apk && \
tar -xf /ish/apk/main/x86/apk-tools-static-2.10.5-r1.apk -C / && \
apk.static add apk-tools && \
rm /sbin/apk.static

app/APKFilesystem.m

@@ -154,6 +154,16 @@ static int apkfs_close(struct fd *fd) {
     return 0;
 }
 
+static int apkfs_getpath(struct fd *fd, char *buf) {
+    if (fd->ops == &apkfs_dir_ops) {
+        strcpy(buf, "");
+    } else if (fd->ops == &apkfs_file_ops) {
+        NSBundleResourceRequest *req = (__bridge NSBundleResourceRequest *) fd->data;
+        strcpy(buf, [@"/" stringByAppendingString:[req.tags.anyObject stringByReplacingOccurrencesOfString:@":" withString:@"/"]].UTF8String);
+    }
+    return 0;
+}
+
 static int apkfs_dir_readdir(struct fd *fd, struct dir_entry *entry) {
     return 0;
 }
@@ -164,6 +174,7 @@ static int apkfs_dir_readdir(struct fd *fd, struct dir_entry *entry) {
     .open = apkfs_open,
     .fstat = apkfs_fstat,
     .close = apkfs_close,
+    .getpath = apkfs_getpath,
 };
 
 static const struct fd_ops apkfs_dir_ops = {

app/AppDelegate.m

@@ -65,17 +65,19 @@ - (int)boot {
     int err = mount_root(&fakefs, root.fileSystemRepresentation);
     if (err < 0)
         return err;
+
     fs_register(&iosfs);
     fs_register(&iosfs_unsafe);
+    fs_register(&apkfs);
 
     // need to do this first so that we can have a valid current for the generic_mknod calls
     err = become_first_process();
     if (err < 0)
         return err;
 
-    // /etc/ish-version is the last ish version that opened this root. Not used for anything yet, but could be used to know whether to change the root if needed in a future update.
+    // /ish/version is the last ish version that opened this root. Not used for anything yet, but could be used to know whether to change the root if needed in a future update.
     BOOL has_ish_version = NO;
-    struct fd *ish_version = generic_open("/ish/version", O_WRONLY_|O_TRUNC_, 0644);
+    struct fd *ish_version = generic_open("/ish/version", O_WRONLY_|O_CREAT_|O_TRUNC_, 0644);
     if (!IS_ERR(ish_version)) {
         has_ish_version = YES;
         NSString *version = NSBundle.mainBundle.infoDictionary[(__bridge NSString *) kCFBundleVersionKey];
@@ -85,7 +87,6 @@ - (int)boot {
     }
 
     if (has_ish_version && [NSBundle.mainBundle URLForResource:@"OnDemandResources" withExtension:@"plist"] != nil) {
-        fs_register(&apkfs);
         generic_mkdirat(AT_PWD, "/ish/apk", 0755);
         do_mount(&apkfs, "apk", "/ish/apk", "", 0);
     }