From 00bc8547ca33a452c1f30dbc38430b88f9414b69 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Tue, 31 Jan 2023 00:04:57 +0100
Subject: [PATCH] Add option to filter files by inode number

Add the option on Unix systems to filter files by their inode number.

The Windows equivalent FileIndex is not yet stabilized, see
https://github.com/rust-lang/rust/issues/63010.

This is especially useful to debug audit records, e.g.:

    Jan 30 17:48:55 laptop audit: PATH item=0 name="pulse" inode=7340042 dev=fe:03 mode=040700 ouid=1001 ogid=1001 rdev=00:00 obj=system_u:object_r:unlabeled_t:s0 nametype=NORMAL cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0

Closes: #880
---
 README.md     |  1 +
 doc/fd.1      |  3 +++
 src/cli.rs    | 14 ++++++++++++++
 src/config.rs |  4 ++++
 src/main.rs   |  4 ++++
 src/walk.rs   | 14 ++++++++++++++
 6 files changed, 40 insertions(+)

diff --git a/README.md b/README.md
index 376148f34..310e7e2a5 100644
--- a/README.md
+++ b/README.md
@@ -320,6 +320,7 @@ Options:
                                    executable (x), empty (e), socket (s), pipe (p), char-device
                                    (c), block-device (b)
   -e, --extension <ext>            Filter by file extension
+      --inum <num>                 Filter by inode number
   -S, --size <size>                Limit results based on the size of files
       --changed-within <date|dur>  Filter by file modification time (newer than)
       --changed-before <date|dur>  Filter by file modification time (older than)
diff --git a/doc/fd.1 b/doc/fd.1
index 501bb1598..14b7bbc5b 100644
--- a/doc/fd.1
+++ b/doc/fd.1
@@ -271,6 +271,9 @@ Always colorize output.
 .BI "\-j, \-\-threads " num
 Set number of threads to use for searching & executing (default: number of available CPU cores).
 .TP
+.BI "\-\-inum " num
+Filter files by their inode number.
+.TP
 .BI "\-S, \-\-size " size
 Limit results based on the size of files using the format
 .I <+-><NUM><UNIT>
diff --git a/src/cli.rs b/src/cli.rs
index 601250fef..83da037a5 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -375,6 +375,20 @@ pub struct Opts {
     )]
     pub extensions: Option<Vec<String>>,
 
+    /// Filter files by their inode number.
+    /// Format: [inum].
+    ///
+    /// Examples:
+    /// {n}    --inum 4242
+    #[cfg(unix)]
+    #[arg(
+        long,
+        value_name = "inode-number",
+        help = "Filter by inode number",
+        long_help
+    )]
+    pub inum: Option<u64>,
+
     /// Limit results based on the size of files using the format <+-><NUM><UNIT>.
     ///    '+': file size must be greater than or equal to this
     ///    '-': file size must be less than or equal to this
diff --git a/src/config.rs b/src/config.rs
index d0a2fd209..03b6a7241 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -47,6 +47,10 @@ pub struct Config {
     /// Whether elements of output should be separated by a null character
     pub null_separator: bool,
 
+    #[cfg(unix)]
+    /// The inode number to search for.
+    pub inode_number: Option<u64>,
+
     /// The maximum search depth, or `None` if no maximum search depth should be set.
     ///
     /// A depth of `1` includes all files under the current directory, a depth of `2` also includes
diff --git a/src/main.rs b/src/main.rs
index 764b7e340..eb5fc14ab 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -206,6 +206,8 @@ fn construct_config(mut opts: Opts, pattern_regexps: &[String]) -> Result<Config
         .unwrap_or_else(|| std::path::MAIN_SEPARATOR.to_string());
     check_path_separator_length(path_separator.as_deref())?;
 
+    #[cfg(unix)]
+    let inode_number = std::mem::take(&mut opts.inum);
     let size_limits = std::mem::take(&mut opts.size);
     let time_constraints = extract_time_constraints(&opts)?;
     #[cfg(unix)]
@@ -303,6 +305,8 @@ fn construct_config(mut opts: Opts, pattern_regexps: &[String]) -> Result<Config
         batch_size: opts.batch_size,
         exclude_patterns: opts.exclude.iter().map(|p| String::from("!") + p).collect(),
         ignore_files: std::mem::take(&mut opts.ignore_file),
+        #[cfg(unix)]
+        inode_number,
         size_constraints: size_limits,
         time_constraints,
         #[cfg(unix)]
diff --git a/src/walk.rs b/src/walk.rs
index a9034c9be..87792f5f8 100644
--- a/src/walk.rs
+++ b/src/walk.rs
@@ -2,6 +2,8 @@ use std::borrow::Cow;
 use std::ffi::OsStr;
 use std::io::{self, Write};
 use std::mem;
+#[cfg(unix)]
+use std::os::unix::fs::MetadataExt;
 use std::path::PathBuf;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex, MutexGuard};
@@ -550,6 +552,18 @@ impl WorkerState {
                     }
                 }
 
+                // Filter out unwanted inode numbers.
+                #[cfg(unix)]
+                if let Some(inode_number) = config.inode_number {
+                    if let Some(metadata) = entry.metadata() {
+                        if inode_number != metadata.ino() {
+                            return ignore::WalkState::Continue;
+                        }
+                    } else {
+                        return ignore::WalkState::Continue;
+                    }
+                }
+
                 #[cfg(unix)]
                 {
                     if let Some(ref owner_constraint) = config.owner_constraint {