tests: dd: add skip-seek-past-dev tests

These tests try to read or write past a block device, where the block device is either given as
stdin or stdout. It requires access to the block device, and therefore is executed as root. For now,
it is assumed that a block device "/dev/sda1" with a size smaller than 10000000000000000 exists.

tests/by-util/test_dd.rs

@@ -4,6 +4,8 @@
 // file that was distributed with this source code.
 // spell-checker:ignore fname, tname, fpath, specfile, testfile, unspec, ifile, ofile, outfile, fullblock, urand, fileio, atoe, atoibm, availible, behaviour, bmax, bremain, btotal, cflags, creat, ctable, ctty, datastructures, doesnt, etoa, fileout, fname, gnudd, iconvflags, iseek, nocache, noctty, noerror, nofollow, nolinks, nonblock, oconvflags, oseek, outfile, parseargs, rlen, rmax, rposition, rremain, rsofar, rstat, sigusr, sigval, wlen, wstat abcdefghijklm abcdefghi nabcde nabcdefg abcdefg
 
+#[cfg(unix)]
+use crate::common::util::run_ucmd_as_root_with_stdin_stdout;
 use crate::common::util::TestScenario;
 #[cfg(all(not(windows), feature = "printf"))]
 use crate::common::util::{UCommand, TESTS_BINARY};
@@ -1566,3 +1568,45 @@ fn test_nocache_file() {
         .succeeds()
         .stderr_only("2048+0 records in\n2048+0 records out\n");
 }
+
+#[test]
+#[cfg(unix)]
+fn test_skip_past_dev() {
+    // NOTE: This test intends to trigger code which can only be reached with root permissions.
+    let ts = TestScenario::new(util_name!());
+
+    if let Ok(result) = run_ucmd_as_root_with_stdin_stdout(
+        &ts,
+        &["bs=1", "skip=10000000000000000", "count=0", "status=noxfer"],
+        Some("/dev/sda1"),
+        None,
+    ) {
+        result.stderr_contains("dd: 'standard input': cannot skip: Invalid argument");
+        result.stderr_contains("0+0 records in");
+        result.stderr_contains("0+0 records out");
+        result.code_is(1);
+    } else {
+        print!("TEST SKIPPED");
+    }
+}
+
+#[test]
+#[cfg(unix)]
+fn test_seek_past_dev() {
+    // NOTE: This test intends to trigger code which can only be reached with root permissions.
+    let ts = TestScenario::new(util_name!());
+
+    if let Ok(result) = run_ucmd_as_root_with_stdin_stdout(
+        &ts,
+        &["bs=1", "seek=10000000000000000", "count=0", "status=noxfer"],
+        None,
+        Some("/dev/sda1"),
+    ) {
+        result.stderr_contains("dd: 'standard output': cannot seek: Invalid argument");
+        result.stderr_contains("0+0 records in");
+        result.stderr_contains("0+0 records out");
+        result.code_is(1);
+    } else {
+        print!("TEST SKIPPED");
+    }
+}