Custom recurse globs and readme

README.md

@@ -5,7 +5,7 @@
 
 **melamine** is a better file shredder
 
-for linux<br/>
+it runs on linux (Ubuntu tested) for now<br/>
 
 [Installation](#installation) •
 [Example](#example) •
@@ -28,7 +28,24 @@ python3 -m pip install .
 
 ## Example
 
-todo
+melamine is not yet ready for production use. If you'd like to try it, generate dummy files below. Preferably, do this on a separate mount point than any essential files or in a virtual machine.
+
+Currently, only inode discovery and the beginnings of ext2/3 and zfs support exist.
+
+```bash
+rm -rf /tmp/melamine && mkdir -p /tmp/melamine;
+rm -rf /tmp/melamine_hardlinks && mkdir -p /tmp/melamine_hardlinks;
+for i in $(seq 1 4); do dd if=/dev/urandom of=/tmp/melamine/test_$i bs=1 count=$(( RANDOM % 256 * 256 )); done;
+ln /tmp/melamine/test_1 /tmp/melamine_hardlinks/hardlink_1;
+ln /tmp/melamine/test_2 /tmp/melamine_hardlinks/hardlink_2;
+```
+
+You can then confirm that the two hardlink inodes match using `ls -li`.
+
+```bash
+ls -li /tmp/melamine/test_*;
+ls -li /tmp/melamine_hardlinks/hardlink_*;
+```
 
 ## Contributing
 

melamine/fileops.py

@@ -1,5 +1,6 @@
 import asyncio
 from collections.abc import Generator
+from typing import List
 
 import aiofiles
 from aiopath import AsyncPath
@@ -9,6 +10,7 @@ from .filesystems import FSHandlers
 from .logs import logger
 
 
+@lru_cache(maxsize=4096)
 async def find_mount(path: AsyncPath) -> AsyncPath:
     """Find the mount point for a given path."""
     path = await path.absolute()
@@ -24,6 +26,24 @@ async def get_all_mounts() -> Generator:
             yield line.split()[1]
 
 
+async def mount_bound_rglob(path: AsyncPath, mount: AsyncPath, pattern: str, ignoredirs: List[AsyncPath]) -> Generator:
+    """Recursively glob a path, but stop at mount points."""
+    path = await path.absolute()
+    # Skip any ignored directories/files with a sanity check
+    for ignore in ignoredirs:
+        if str(path).startswith(str(ignore)) and await path.is_relative_to(ignore):
+            logger.info(f"Skipping ignored subdir: {path}")
+            return
+    if await path.is_dir():
+        if await find_mount(path) == mount:
+            logger.info(f"Skipping differently mounted subdir: {path} (wanted {mount}))")
+            return
+        for subpath in await path.glob(pattern):
+            async for subitem in mount_bound_rglob(subpath, mount, pattern):
+                yield subitem
+    yield path
+
+
 @lru_cache(maxsize=1024)
 async def mount_to_fs_handler(path: AsyncPath) -> str:
     # TODO: This is a hacky way to get the filesystem type, but it works for now.

melamine/shred.py

@@ -7,6 +7,7 @@ from aiopath import AsyncPath
 from .classes import get_all_hardlinks
 from .classes import ShredDir
 from .classes import ShredFile
+from .fileops import mount_bound_rglob
 from .logs import logger
 
 IGNORE_GLOBAL = ("/proc", "/dev", "/sys")
@@ -84,17 +85,13 @@ async def main(job: argparse.Namespace) -> bool:
                 if await item.is_dir():
                     if str(item) in IGNORE_GLOBAL:
                         continue
-                    async for subitem in item.rglob("*"):
-                        if any(str(subitem).startswith(str(path)) for path in job.ignoredir):
-                            continue
+                    async for subitem in mount_bound_rglob(item, mount_point, "*", job.ignoredir):
                         tasks.append(check_inode_and_unlink(subitem, inodes))
                 else:
                     tasks.append(check_inode_and_unlink(item, inodes))
         else:
             logger.info(f"Checking non-root filesystem mount: {str(mount_point)}")
-            async for item in mount_point.rglob("*"):
-                if any(str(item).startswith(str(path)) for path in job.ignoredir):
-                    continue
+            async for item in mount_bound_rglob(mount_point, mount_point, "*", job.ignoredir):
                 tasks.append(check_inode_and_unlink(item, inodes))
         done, _ = await asyncio.wait(tasks)
         for task in done: