Added iospatcher to lib and CLI

Everything but the no-shared flag is working right now. Getting no-shared to work properly will take a little more work because right now there's nothing to guarantee that the content records are synced between the TMD and content objects in a title. This means that updating any content in a title will result in the records being out of sync and the written TMD will not match the actual state of the content when it was dumped.
To mitigate this, I intend on making the content records in the content struct a reference to the content records in the TMD, so that they are the same object and therefore always in sync.

src/title/iospatcher.rs

@@ -0,0 +1,136 @@
+// title/iospatcher.rs from ruswtii (c) 2025 NinjaCheetah & Contributors
+// https://github.com/NinjaCheetah/rustwii
+//
+// Module for applying patches to IOSes using a Title.
+
+use std::io::{Cursor, Seek, SeekFrom, Write};
+use thiserror::Error;
+use crate::title;
+use crate::title::content;
+
+#[derive(Debug, Error)]
+pub enum IOSPatcherError {
+    #[error("this title is not an IOS")]
+    NotIOS,
+    #[error("the required module \"{0}\" could not be found, this may not be a valid IOS")]
+    ModuleNotFound(String),
+    #[error("failed to get IOS content")]
+    Content(#[from] content::ContentError),
+    #[error("failed to set content in Title")]
+    Title(#[from] title::TitleError),
+    #[error("IOS content is invalid")]
+    IO(#[from] std::io::Error),
+}
+
+pub fn ios_find_module(module_keyword: String, ios: &title::Title) -> Result<usize, IOSPatcherError> {
+    let content_records = ios.tmd.content_records();
+    let tid = hex::encode(ios.tmd.title_id());
+
+    // If the TID is not a valid IOS TID, then return NotIOS. It's possible that this could catch
+    // some modified IOSes that currently have a non-IOS TID but that's weird and if you're doing
+    // that please stop.
+    if !tid[..8].eq("00000001") || tid[8..].eq("00000001") || tid[8..].eq("00000002") {
+        return Err(IOSPatcherError::NotIOS);
+    }
+
+    // Find the module's keyword in the content, and return the (true) index of the content that
+    // it was found in.
+    let keyword = module_keyword.as_bytes();
+    for record in content_records {
+        let content_decrypted = ios.get_content_by_index(record.index as usize)?;
+        let offset = content_decrypted
+            .windows(keyword.len())
+            .position(|window| window == keyword);
+        if offset.is_some() {
+            return Ok(record.index as usize);
+        }
+    }
+
+    // If we didn't return early by finding the offset, then return a ModuleNotFound error.
+    Err(IOSPatcherError::ModuleNotFound(module_keyword))
+}
+
+fn ios_apply_patches(
+    target_content: &mut Cursor<Vec<u8>>,
+    find_seq: Vec<Vec<u8>>,
+    replace_seq: Vec<Vec<u8>>
+) -> Result<i32, IOSPatcherError> {
+    let mut patch_count = 0;
+    for idx in 0..find_seq.len() {
+        let offset = target_content.get_ref()
+            .windows(find_seq[idx].len())
+            .position(|window| window == find_seq[idx]);
+        if let Some(offset) = offset {
+            target_content.seek(SeekFrom::Start(offset as u64))?;
+            target_content.write_all(&replace_seq[idx])?;
+            patch_count += 1;
+        }
+    }
+
+    Ok(patch_count)
+}
+
+pub fn ios_patch_sigchecks(ios: &mut title::Title, es_index: usize) -> Result<i32, IOSPatcherError> {
+    let target_content = ios.get_content_by_index(es_index)?;
+    let mut buf = Cursor::new(target_content);
+
+    let find_seq = vec![vec![0x20, 0x07, 0x23, 0xa2], vec![0x20, 0x07, 0x4b, 0x0b]];
+    let replace_seq: Vec<Vec<u8>> = vec![vec![0x20, 0x00, 0x23, 0xa2], vec![0x20, 0x00, 0x4b, 0x0b]];
+    let patch_count = ios_apply_patches(&mut buf, find_seq, replace_seq)?;
+
+    ios.set_content(buf.get_ref(), es_index, None, None)?;
+
+    Ok(patch_count)
+}
+
+pub fn ios_patch_es_identify(ios: &mut title::Title, es_index: usize) -> Result<i32, IOSPatcherError> {
+    let target_content = ios.get_content_by_index(es_index)?;
+    let mut buf = Cursor::new(target_content);
+
+    let find_seq = vec![vec![0x28, 0x03, 0xd1, 0x23]];
+    let replace_seq = vec![vec![0x28, 0x03, 0x00, 0x00]];
+    let patch_count = ios_apply_patches(&mut buf, find_seq, replace_seq)?;
+
+    ios.set_content(buf.get_ref(), es_index, None, None)?;
+
+    Ok(patch_count)
+}
+
+pub fn ios_patch_dev_flash(ios: &mut title::Title, es_index: usize) -> Result<i32, IOSPatcherError> {
+    let target_content = ios.get_content_by_index(es_index)?;
+    let mut buf = Cursor::new(target_content);
+
+    let find_seq = vec![vec![0x42, 0x8b, 0xd0, 0x01, 0x25, 0x66]];
+    let replace_seq = vec![vec![0x42, 0x8b, 0xe0, 0x01, 0x25, 0x66]];
+    let patch_count = ios_apply_patches(&mut buf, find_seq, replace_seq)?;
+
+    ios.set_content(buf.get_ref(), es_index, None, None)?;
+
+    Ok(patch_count)
+}
+
+pub fn ios_patch_allow_downgrade(ios: &mut title::Title, es_index: usize) -> Result<i32, IOSPatcherError> {
+    let target_content = ios.get_content_by_index(es_index)?;
+    let mut buf = Cursor::new(target_content);
+
+    let find_seq = vec![vec![0xd2, 0x01, 0x4e, 0x56]];
+    let replace_seq = vec![vec![0xe0, 0x01, 0x4e, 0x56]];
+    let patch_count = ios_apply_patches(&mut buf, find_seq, replace_seq)?;
+
+    ios.set_content(buf.get_ref(), es_index, None, None)?;
+
+    Ok(patch_count)
+}
+
+pub fn ios_patch_drive_inquiry(ios: &mut title::Title, dip_index: usize) -> Result<i32, IOSPatcherError> {
+    let target_content = ios.get_content_by_index(dip_index)?;
+    let mut buf = Cursor::new(target_content);
+
+    let find_seq = vec![vec![0x49, 0x4c, 0x23, 0x90, 0x68, 0x0a]];
+    let replace_seq = vec![vec![0x20, 0x00, 0xe5, 0x38, 0x68, 0x0a]];
+    let patch_count = ios_apply_patches(&mut buf, find_seq, replace_seq)?;
+
+    ios.set_content(buf.get_ref(), dip_index, None, None)?;
+
+    Ok(patch_count)
+}