inject /var/subsidiary/TweakDylib.dylib

demo.x

%hookf(int, posix_spawn, pid_t *pid, const char *orig_path, const posix_spawn_file_actions_t *file_actions, const posix_spawnattr_t *attrp, char *const orig_argv[], char *const envp[]) {
 //GUESS: Add DYLD_INSERT_LIBRARIES to envp
 //This is example code that I think should (theoretically) work?
 //compile this dylib and put it in launchd, then CT sign
 //adds a dylib to every process (that being, "/var/subsidiary/TweakDylib.dylib")
 //dylib is sandboxed btw, but should be possible for unsandboxed dylibs as well theoretically, see opainject and the nullconga pdf, not in this example code tho bc idc for now
 //in real world we shouldn't want to insert this dylib in *everything* and only insert it in stuff it should be inserted in, but once again, only an example
 int addingEnvVar = 0; //int/bool that is 1 if we're adding DYLD_INSERT_LIBRARIES=, and 0 if we're modifying it
 int dyldLibIndex = -1;
 char **ptr;
 int index = 0;
 for (ptr = envp; *ptr != NULL; ptr++) {
  if (strlen(*ptr) > 21) { //check if string size if 22 or above, aka length of DYLD_INSERT_LIBRARIES= string
   if(strncmp(*ptr, "DYLD_INSERT_LIBRARIES=", 22) == 0) { //check if string in envp starts with DYLD_INSERT_LIBRARIES=
    dyldLibIndex = index;
   }
  }
  index++;
 }
 if (dyldLibIndex == -1) {
  addingEnvVar = 1;
  dyldLibIndex = index;
  index++;
 }
 const char* newEnvp[index];
 //add env vars to newEnvp from our current environment vars
 int index2 = 0;
 for (ptr = envp; *ptr != NULL; ptr++) {
  newEnvp[index2] = *ptr;
  index2++;
 }
 if (addingEnvVar) {
  //add DYLD_INSERT_LIBRARIES env var 
  //index2 should be equal to dyldLibIndex at this moment
  newEnvp[index2] = "DYLD_INSERT_LIBRARIES=/var/subsidiary/TweakDylib.dylib";
 } else {
  //modify existing DYLD_INSERT_LIBRARIES env var to use /var/subsidiary/TweakDylib.dylib
  //ex if DYLD_INSERT_LIBRARIES env var is DYLD_INSERT_LIBRARIES=/some/lib.dylib, it should now be DYLD_INSERT_LIBRARIES=/var/subsidiary/TweakDylib.dylib:/some/lib.dylib
  NSString *string = [[NSString alloc]initWithUTF8String:newEnvp[dyldLibIndex]]; //make the DYLD_INSERT_LIBRARIES env var to objc string
  string = [NSString stringWithFormat:@"DYLD_INSERT_LIBRARIES=/var/subsidiary/TweakDylib.dylib:%@",[str substringFromIndex:22]];
  newEnvp[dyldLibIndex] = [string UTF8String];
 }
 return %orig(pid, orig_path, file_actions, attrp, orig_argv, newEnvp);
}

this is dumb and wont work