Add setsid implementation

tests/by-util/test_setsid.rs

@@ -0,0 +1,174 @@
+// This file is part of the uutils util-linux package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+#[cfg(target_family = "unix")]
+mod unix {
+    use crate::common::util::{TestScenario, UCommand, TESTS_BINARY};
+
+    #[test]
+    fn test_invalid_arg() {
+        new_ucmd!().arg("--definitely-invalid").fails().code_is(1);
+
+        new_ucmd!()
+            .arg("-f")
+            .fails()
+            .code_is(1)
+            .stderr_is("setsid: no command specified\n");
+    }
+
+    #[test]
+    fn fork_isolates_child_exit_code() {
+        new_ucmd!()
+            .arg("-f")
+            .arg("/usr/bin/false")
+            .succeeds()
+            .no_output();
+    }
+
+    #[test]
+    fn non_fork_returns_child_exit_code() {
+        new_ucmd!()
+            .arg("/usr/bin/false")
+            .fails()
+            .code_is(1)
+            .no_output();
+    }
+
+    #[test]
+    fn fork_wait_returns_child_exit_code() {
+        new_ucmd!()
+            .arg("-f")
+            .arg("-w")
+            .arg("/usr/bin/false")
+            .fails()
+            .code_is(1)
+            .no_output();
+    }
+
+    #[test]
+    fn non_fork_returns_not_found_error() {
+        new_ucmd!()
+        .arg("/usr/bin/this-tool-does-not-exist-hopefully")
+        .fails()
+        .code_is(127)
+        .stderr_is("setsid: failed to execute /usr/bin/this-tool-does-not-exist-hopefully: No such file or directory\n");
+    }
+
+    #[test]
+    fn non_fork_on_non_executable_returns_permission_denied_error() {
+        new_ucmd!()
+            .arg("/etc/passwd")
+            .fails()
+            .code_is(126)
+            .stderr_is("setsid: failed to execute /etc/passwd: Permission denied\n");
+    }
+
+    #[test]
+    fn fork_isolates_not_found_error() {
+        new_ucmd!()
+            .arg("-f")
+            .arg("/usr/bin/this-tool-does-not-exist-hopefully")
+            .succeeds();
+        // no test for output, as it's a race whether the not found error gets printed
+        // quickly enough, potential flakyness
+    }
+
+    #[test]
+    fn unprivileged_user_cannot_steal_controlling_tty() {
+        let shell_cmd =
+            format!("{TESTS_BINARY} setsid -w -c {TESTS_BINARY} setsid -w -c /b/usrin/true");
+        UCommand::new()
+            .terminal_simulation(true)
+            .arg(&shell_cmd)
+            .fails()
+            .code_is(1)
+            .no_stdout()
+            .stderr_is("setsid: failed to set the controlling terminal: Permission denied\r\n");
+    }
+
+    #[cfg(target_os = "linux")]
+    #[test]
+    fn unprivileged_user_can_take_new_controlling_tty() {
+        let shell_cmd = format!(
+            "/usr/bin/cat /proc/self/stat; {TESTS_BINARY} setsid -w -c /usr/bin/cat /proc/self/stat"
+        );
+
+        let cmd_result = UCommand::new()
+            .terminal_simulation(true)
+            .arg(&shell_cmd)
+            .succeeds();
+
+        let output = cmd_result.code_is(0).no_stderr().stdout_str();
+
+        // /proc/self/stat format has controlling terminal as the 7th
+        // space-separated item; if we managed to change the controlling
+        // terminal, we should see a difference there
+        let (before, after) = output
+            .split_once('\n')
+            .expect("expected 2 lines of output at least");
+        let before = before
+            .split_whitespace()
+            .nth(6)
+            .expect("unexpected stat format");
+        let after = after
+            .split_whitespace()
+            .nth(6)
+            .expect("unexpected stat format");
+
+        assert_ne!(before, after);
+    }
+
+    #[cfg(target_os = "linux")]
+    #[test]
+    fn setsid_takes_session_leadership() {
+        let shell_cmd = format!(
+            "/usr/bin/cat /proc/self/stat; {TESTS_BINARY} setsid /usr/bin/cat /proc/self/stat"
+        );
+
+        let cmd_result = UCommand::new()
+            .terminal_simulation(true)
+            .arg(&shell_cmd)
+            .run();
+
+        let output = cmd_result.code_is(0).no_stderr().stdout_str();
+
+        // /proc/self/stat format has sessiion ID as the 6th space-separated
+        // item; if we managed to get session leadership, we should see a
+        // difference there...
+        let (before, after) = output
+            .split_once('\n')
+            .expect("expected 2 lines of output at least");
+        let before = before
+            .split_whitespace()
+            .nth(5)
+            .expect("unexpected stat format");
+        let after = after
+            .split_whitespace()
+            .nth(5)
+            .expect("unexpected stat format");
+
+        assert_ne!(before, after);
+
+        // ...and it should actually be the PID of our child! We take the child
+        // PID here to avoid differences in handling by different shells or
+        // distributions.
+        let pid = after.split_whitespace().next().unwrap();
+        assert_eq!(after, pid);
+    }
+}
+
+#[cfg(not(target_family = "unix"))]
+mod non_unix {
+    use crate::common::util::{TestScenario, UCommand};
+
+    #[test]
+    fn unsupported_platforms() {
+        new_ucmd!()
+            .arg("/usr/bin/true")
+            .fails()
+            .code_is(1)
+            .stderr_is("setsid: `setsid` is unavailable on non-UNIX-like platforms.\n");
+    }
+}

tests/tests.rs

@@ -25,6 +25,10 @@ mod test_ctrlaltdel;
 #[path = "by-util/test_rev.rs"]
 mod test_rev;
 
+#[cfg(feature = "setsid")]
+#[path = "by-util/test_setsid.rs"]
+mod test_setsid;
+
 #[cfg(feature = "last")]
 #[path = "by-util/test_last.rs"]
 mod test_last;