tests: simplify invalid signal determination for kill -l

* src/operand2sig.c (operand2sig): Add a detailed comment explaining
why we validate even very large shell exit status values.
* tests/misc/kill.sh: Add a test case for the ksh scheme.
Simplify the INVALID signal number determination which also avoids
a false failure on systems like FreeBSD 10 with incomplete
signal list (caused by inaccurate NSIG).

diff --git a/src/operand2sig.c b/src/operand2sig.c
index a9fede54be74e1135ed024fa34ea6ccbcb8b988e..62039db286859ceef6e9342e35ff250314d8dd8b 100644 (file)
--- a/src/operand2sig.c
+++ b/src/operand2sig.c
@@ -39,6 +39,17 @@ operand2sig (char const *operand, char *signame)
 
   if (ISDIGIT (*operand))
     {
+      /* Note we don't put a limit on the maximum value passed,
+         because we're checking shell $? values here, and ksh for
+         example will add 256 to the signal value, thus being wider
+         than the number of WEXITSTATUS bits.
+         We could validate that values were not above say
+         ((WEXITSTATUS (~0) << 1) + 1), which would cater for ksh.
+         But some shells may use other adjustments in future to be
+         (forward) compatible with systems that support
+         wider exit status values as discussed at
+         http://austingroupbugs.net/view.php?id=947  */
+
       char *endp;
       long int l = (errno = 0, strtol (operand, &endp, 10));
       int i = l;

diff --git a/tests/misc/kill.sh b/tests/misc/kill.sh
index 27d550ec8ae245a5061088d167de620872c8db8d..779ce3e8f5c8f2164493fd2187c7d59aaeb69773 100755 (executable)
--- a/tests/misc/kill.sh
+++ b/tests/misc/kill.sh
@@ -49,10 +49,15 @@ env kill -t TERM HUP || fail=1
 SIGTERM=$(env kill -l HUP TERM | tail -n1) || fail=1
 test $(env kill -l "$SIGTERM") = TERM || fail=1
 
+# Verify we only consider the lower "signal" bits,
+# to support ksh which just adds 256 to the signal value
+STD_TERM_STATUS=$(expr "$SIGTERM" + 128)
+KSH_TERM_STATUS=$(expr "$SIGTERM" + 256)
+test $(env kill -l $STD_TERM_STATUS $KSH_TERM_STATUS | uniq) = TERM || fail=1
+
 # Verify invalid signal spec is diagnosed
-SIGINVAL=$(env kill -t | tail -n1 | cut -f1 -d' ')
-SIGINVAL=$(expr "$SIGINVAL" + 1)
-returns_ 1 env kill -l "$SIGINVAL" 0 || fail=1
+returns_ 1 env kill -l -1 || fail=1
+returns_ 1 env kill -l -1 0 || fail=1
 returns_ 1 env kill -l INVALID TERM || fail=1
 
 Exit $fail