feat(cksum): improve debug output for single file operations

src/uu/cksum/Cargo.toml

@@ -19,7 +19,12 @@ path = "src/cksum.rs"
 
 [dependencies]
 clap = { workspace = true }
-uucore = { workspace = true, features = ["checksum", "encoding", "sum"] }
+uucore = { workspace = true, features = [
+  "checksum",
+  "encoding",
+  "sum",
+  "hardware",
+] }
 hex = { workspace = true }
 fluent = { workspace = true }
 

src/uu/cksum/locales/en-US.ftl

@@ -27,6 +27,7 @@ cksum-help-status = don't output anything, status code shows success
 cksum-help-quiet = don't print OK for each successfully verified file
 cksum-help-ignore-missing = don't fail or report status for missing files
 cksum-help-zero = end each output line with NUL, not newline, and disable file name escaping
+cksum-help-debug = print CPU hardware capability detection info used by cksum
 
 # Error messages
 cksum-error-is-directory = { $file }: Is a directory

src/uu/cksum/locales/fr-FR.ftl

@@ -27,6 +27,7 @@ cksum-help-status = ne rien afficher, le code de statut indique le succès
 cksum-help-quiet = ne pas afficher OK pour chaque fichier vérifié avec succès
 cksum-help-ignore-missing = ne pas échouer ou signaler le statut pour les fichiers manquants
 cksum-help-zero = terminer chaque ligne de sortie avec NUL, pas un saut de ligne, et désactiver l'échappement des noms de fichiers
+cksum-help-debug = afficher les informations de débogage sur la détection de la prise en charge matérielle du processeur
 
 # Messages d'erreur
 cksum-error-is-directory = { $file } : Est un répertoire

src/uu/cksum/src/cksum.rs

@@ -20,9 +20,34 @@ use uucore::checksum::{
     sanitize_sha2_sha3_length_str,
 };
 use uucore::error::UResult;
+use uucore::hardware::CpuFeatures;
 use uucore::line_ending::LineEnding;
 use uucore::{format_usage, translate};
 
+/// Print CPU hardware capability detection information to stderr
+/// This matches GNU cksum's --debug behavior
+fn print_cpu_debug_info() {
+    let features = CpuFeatures::detect();
+
+    fn print_feature(name: &str, available: bool) {
+        if available {
+            eprintln!("cksum: using {name} hardware support");
+        } else {
+            eprintln!("cksum: {name} support not detected");
+        }
+    }
+
+    // x86/x86_64
+    print_feature("avx512", features.has_avx512());
+    print_feature("avx2", features.has_avx2());
+    print_feature("pclmul", features.has_pclmul());
+
+    // ARM aarch64
+    if cfg!(target_arch = "aarch64") {
+        print_feature("vmull", features.has_vmull());
+    }
+}
+
 mod options {
     pub const ALGORITHM: &str = "algorithm";
     pub const FILE: &str = "file";
@@ -40,6 +65,7 @@ mod options {
     pub const IGNORE_MISSING: &str = "ignore-missing";
     pub const QUIET: &str = "quiet";
     pub const ZERO: &str = "zero";
+    pub const DEBUG: &str = "debug";
 }
 
 /// cksum has a bunch of legacy behavior. We handle this in this function to
@@ -181,6 +207,11 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         matches.get_flag(options::BASE64),
     );
 
+    // Print hardware debug info if requested
+    if matches.get_flag(options::DEBUG) {
+        print_cpu_debug_info();
+    }
+
     let opts = ChecksumComputeOptions {
         algo_kind: algo,
         output_format,
@@ -317,5 +348,11 @@ pub fn uu_app() -> Command {
                 .help(translate!("cksum-help-zero"))
                 .action(ArgAction::SetTrue),
         )
+        .arg(
+            Arg::new(options::DEBUG)
+                .long(options::DEBUG)
+                .help(translate!("cksum-help-debug"))
+                .action(ArgAction::SetTrue),
+        )
         .after_help(translate!("cksum-after-help"))
 }

tests/by-util/test_cksum.rs

@@ -10,9 +10,8 @@ use uutests::util::TestScenario;
 use uutests::util::log_info;
 use uutests::util_name;
 
-const ALGOS: [&str; 12] = [
-    "sysv", "bsd", "crc", "crc32b", "md5", "sha1", "sha224", "sha256", "sha384", "sha512",
-    "blake2b", "sm3",
+const ALGOS: [&str; 11] = [
+    "sysv", "bsd", "crc", "md5", "sha1", "sha224", "sha256", "sha384", "sha512", "blake2b", "sm3",
 ];
 const SHA_LENGTHS: [u32; 4] = [224, 256, 384, 512];
 
@@ -2876,3 +2875,113 @@ mod format_mix {
             .stderr_contains("cksum: WARNING: 1 line is improperly formatted");
     }
 }
+
+#[cfg(not(target_os = "android"))]
+mod debug_flag {
+    use super::*;
+
+    #[test]
+    fn test_debug_flag() {
+        // Test with default CRC algorithm - should output CPU feature detection
+        new_ucmd!()
+            .arg("--debug")
+            .arg("lorem_ipsum.txt")
+            .succeeds()
+            .stdout_is_fixture("crc_single_file.expected")
+            .stderr_contains("avx512")
+            .stderr_contains("avx2")
+            .stderr_contains("pclmul");
+
+        // Test with MD5 algorithm - CPU detection should be same regardless of algorithm
+        new_ucmd!()
+            .arg("--debug")
+            .arg("-a")
+            .arg("md5")
+            .arg("lorem_ipsum.txt")
+            .succeeds()
+            .stdout_is_fixture("md5_single_file.expected")
+            .stderr_contains("avx512")
+            .stderr_contains("avx2")
+            .stderr_contains("pclmul");
+
+        // Test with stdin - CPU detection should appear once
+        new_ucmd!()
+            .arg("--debug")
+            .pipe_in("test")
+            .succeeds()
+            .stderr_contains("avx512")
+            .stderr_contains("avx2")
+            .stderr_contains("pclmul");
+
+        // Test with multiple files - CPU detection should appear once, not per file
+        new_ucmd!()
+            .arg("--debug")
+            .arg("lorem_ipsum.txt")
+            .arg("alice_in_wonderland.txt")
+            .succeeds()
+            .stdout_is_fixture("crc_multiple_files.expected")
+            .stderr_str_check(|stderr| {
+                // Verify CPU detection happens only once by checking the count of each feature line
+                let avx512_count = stderr
+                    .lines()
+                    .filter(|line| line.contains("avx512"))
+                    .count();
+                let avx2_count = stderr.lines().filter(|line| line.contains("avx2")).count();
+                let pclmul_count = stderr
+                    .lines()
+                    .filter(|line| line.contains("pclmul"))
+                    .count();
+
+                avx512_count == 1 && avx2_count == 1 && pclmul_count == 1
+            });
+    }
+
+    #[test]
+    fn test_debug_with_algorithms() {
+        // Test with SHA256 - CPU detection should be same regardless of algorithm
+        new_ucmd!()
+            .arg("--debug")
+            .arg("-a")
+            .arg("sha256")
+            .arg("lorem_ipsum.txt")
+            .succeeds()
+            .stderr_contains("avx512")
+            .stderr_contains("avx2")
+            .stderr_contains("pclmul");
+
+        // Test with BLAKE2b default length
+        new_ucmd!()
+            .arg("--debug")
+            .arg("-a")
+            .arg("blake2b")
+            .arg("lorem_ipsum.txt")
+            .succeeds()
+            .stderr_contains("avx512")
+            .stderr_contains("avx2")
+            .stderr_contains("pclmul");
+
+        // Test with BLAKE2b custom length
+        new_ucmd!()
+            .arg("--debug")
+            .arg("-a")
+            .arg("blake2b")
+            .arg("--length")
+            .arg("256")
+            .arg("lorem_ipsum.txt")
+            .succeeds()
+            .stderr_contains("avx512")
+            .stderr_contains("avx2")
+            .stderr_contains("pclmul");
+
+        // Test with SHA1
+        new_ucmd!()
+            .arg("--debug")
+            .arg("-a")
+            .arg("sha1")
+            .arg("lorem_ipsum.txt")
+            .succeeds()
+            .stderr_contains("avx512")
+            .stderr_contains("avx2")
+            .stderr_contains("pclmul");
+    }
+}