Merge pull request #126 from cakebaker/pgrep_fix_111

pgrep: handle empty /proc/<PID>/cmdline with -a

src/uu/pgrep/src/pgrep.rs

@@ -85,7 +85,15 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
 
         let formatted: Vec<_> = if matches.get_flag("list-full") {
             pids.into_iter()
-                .map(|it| format!("{} {}", it.pid, it.cmdline))
+                .map(|it| {
+                    // pgrep from procps-ng outputs the process name inside square brackets
+                    // if /proc/<PID>/cmdline is empty
+                    if it.cmdline.is_empty() {
+                        format!("{} [{}]", it.pid, it.clone().status().get("Name").unwrap())
+                    } else {
+                        format!("{} {}", it.pid, it.cmdline)
+                    }
+                })
                 .collect()
         } else if matches.get_flag("list-name") {
             pids.into_iter()

tests/by-util/test_pgrep.rs

@@ -139,3 +139,26 @@ fn test_ignore_case() {
         new_ucmd!().arg("SH").arg(arg).succeeds();
     }
 }
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_list_full() {
+    for arg in ["-a", "--list-full"] {
+        new_ucmd!()
+            .arg("sh")
+            .arg(arg)
+            .succeeds()
+            // (?m) enables multi-line mode
+            .stdout_matches(&Regex::new("(?m)^[1-9][0-9]* .+$").unwrap());
+    }
+}
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_list_full_process_with_empty_cmdline() {
+    new_ucmd!()
+        .arg("kthreadd")
+        .arg("--list-full")
+        .succeeds()
+        .stdout_matches(&Regex::new(r"^[1-9][0-9]* \[kthreadd\]\n$").unwrap());
+}