From 2aa8a3502fd049a3ce13164aa8b289daf2940e04 Mon Sep 17 00:00:00 2001
From: Sudhakar Verma <sudhakar.verma@canonical.com>
Date: Fri, 12 Jan 2024 16:08:47 +0530
Subject: [PATCH 1/3] printf : no infinite loop

---
 src/uu/printf/src/printf.rs  | 10 +++++++++-
 tests/by-util/test_printf.rs |  5 +++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/uu/printf/src/printf.rs b/src/uu/printf/src/printf.rs
index ad42e3894..64a3a35a7 100644
--- a/src/uu/printf/src/printf.rs
+++ b/src/uu/printf/src/printf.rs
@@ -11,7 +11,7 @@ use std::ops::ControlFlow;
 
 use clap::{crate_version, Arg, ArgAction, Command};
 use uucore::error::{UResult, UUsageError};
-use uucore::format::{parse_spec_and_escape, FormatArgument};
+use uucore::format::{parse_spec_and_escape, FormatArgument, FormatItem};
 use uucore::{format_usage, help_about, help_section, help_usage};
 
 const VERSION: &str = "version";
@@ -46,6 +46,14 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         };
     }
 
+    // See #5815 - We don't need to iter on args if no format string seen
+    let format_seen = parse_spec_and_escape(format_string.as_ref())
+        .into_iter()
+        .any(|r| matches!(r, Ok(FormatItem::Spec(_))));
+    if !format_seen {
+        return Ok(());
+    }
+
     while args.peek().is_some() {
         for item in parse_spec_and_escape(format_string.as_ref()) {
             match item?.write(stdout(), &mut args)? {
diff --git a/tests/by-util/test_printf.rs b/tests/by-util/test_printf.rs
index 4f2e1dc10..411285a0c 100644
--- a/tests/by-util/test_printf.rs
+++ b/tests/by-util/test_printf.rs
@@ -649,3 +649,8 @@ fn partial_char() {
 fn char_as_byte() {
     new_ucmd!().args(&["%c", "🙃"]).succeeds().stdout_only("ð");
 }
+
+#[test]
+fn no_infinite_loop() {
+    new_ucmd!().args(&["a", "b"]).succeeds().stdout_only("a");
+}

From 4e5a65ee41372ca9bd35501e251b1b7bf799665e Mon Sep 17 00:00:00 2001
From: Sudhakar Verma <sudhakar.verma@canonical.com>
Date: Fri, 12 Jan 2024 16:23:38 +0530
Subject: [PATCH 2/3] printf: fix clippy warnings

---
 src/uu/printf/src/printf.rs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/uu/printf/src/printf.rs b/src/uu/printf/src/printf.rs
index 64a3a35a7..b0988f7b4 100644
--- a/src/uu/printf/src/printf.rs
+++ b/src/uu/printf/src/printf.rs
@@ -47,9 +47,8 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     }
 
     // See #5815 - We don't need to iter on args if no format string seen
-    let format_seen = parse_spec_and_escape(format_string.as_ref())
-        .into_iter()
-        .any(|r| matches!(r, Ok(FormatItem::Spec(_))));
+    let format_seen =
+        parse_spec_and_escape(format_string.as_ref()).any(|r| matches!(r, Ok(FormatItem::Spec(_))));
     if !format_seen {
         return Ok(());
     }

From cd4568f5d9862ab28dda351c7692c0bd95dcdda7 Mon Sep 17 00:00:00 2001
From: Sudhakar Verma <sudhakar.verma@canonical.com>
Date: Fri, 12 Jan 2024 17:12:30 +0530
Subject: [PATCH 3/3] printf: simplify loop

---
 src/uu/printf/src/printf.rs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/uu/printf/src/printf.rs b/src/uu/printf/src/printf.rs
index b0988f7b4..c98bb59a1 100644
--- a/src/uu/printf/src/printf.rs
+++ b/src/uu/printf/src/printf.rs
@@ -38,17 +38,20 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         None => vec![],
     };
 
+    let mut format_seen = false;
     let mut args = values.iter().peekable();
     for item in parse_spec_and_escape(format_string.as_ref()) {
+        if let Ok(FormatItem::Spec(_)) = item {
+            format_seen = true;
+        }
         match item?.write(stdout(), &mut args)? {
             ControlFlow::Continue(()) => {}
             ControlFlow::Break(()) => return Ok(()),
         };
     }
 
-    // See #5815 - We don't need to iter on args if no format string seen
-    let format_seen =
-        parse_spec_and_escape(format_string.as_ref()).any(|r| matches!(r, Ok(FormatItem::Spec(_))));
+    // Without format specs in the string, the iter would not consume any args,
+    // leading to an infinite loop. Thus, we exit early.
     if !format_seen {
         return Ok(());
     }