[PATCH] Accept ksh88 exit status for SIGINT in shell.exp

[Aditya Vidyadhar Kamath <akamath996@gmail.com>]

From: Aditya Vidyadhar Kamath <aditya.kamath1@ibm.com>

This patch is in continuation to Simon's patch [1].

gdb.base/shell.exp runs "kill -2 $$" under the shell, through both
"shell" ("!") and "pipe" ("|"), and expects $_shell_exitsignal to be 2
and $_shell_exitcode to be void, that is, a shell that dies from the
signal.

On AIX, /bin/sh and /usr/bin/ksh are ksh88.  ksh88 catches SIGINT and
calls exit (130) (128 + SIGINT) instead of dying from the signal.  GDB
therefore sees a normal exit, sets $_shell_exitcode to 130 and leaves
$_shell_exitsignal void.  This is correct reporting by GDB; the test
assumes a shell that is killed by the signal.  The raw wait status of
the shells on AIX 7.3 is:

  /usr/bin/ksh    exited, code 130
  /usr/bin/ksh93  killed by signal 2
  /usr/bin/bash   killed by signal 2

As a result these four tests failed on AIX:

  shell interrupt exitcode
  shell interrupt exitsignal
  pipe interrupt exitcode
  pipe interrupt exitsignal

Add check_shell_interrupt_status, which replaces the duplicated checks.
On AIX it also accepts $_shell_exitcode = 130 together with
$_shell_exitsignal = void.

Tested on AIX 7.3 with a 64-bit GDB: gdb.base/shell.exp now gives
125 passes and no failures.  The four tests above failed before.

[1] https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=bf842a2e8d6e9eb7429444904b1b31c8b85d5fb2
---
 gdb/testsuite/gdb.base/shell.exp | 49 +++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 4 deletions(-)

diff --git a/gdb/testsuite/gdb.base/shell.exp b/gdb/testsuite/gdb.base/shell.exp
index 2e6c63585eb..e0f9b9fb1f2 100644
--- a/gdb/testsuite/gdb.base/shell.exp
+++ b/gdb/testsuite/gdb.base/shell.exp
@@ -17,6 +17,49 @@
 
 load_lib completion-support.exp
 
+# Check the convenience variables after a shell command that ran
+# "kill -2 $$".  PREFIX is "shell" or "pipe", and is used to name the
+# tests.
+#
+# Usually the shell dies from SIGINT, so $_shell_exitcode is void and
+# $_shell_exitsignal is 2.
+#
+# On AIX, /bin/sh and /usr/bin/ksh are ksh88.  ksh88 catches SIGINT and
+# calls exit (130) (128 + SIGINT) instead of dying from the signal.  GDB
+# then sees a normal exit and correctly sets $_shell_exitcode to 130 and
+# leaves $_shell_exitsignal void.  Accept that outcome on AIX.  Shells
+# that do die from the signal (e.g. ksh93 or bash) still give the usual
+# result, and are accepted as well.
+
+proc check_shell_interrupt_status { prefix } {
+    global gdb_prompt
+
+    set signaled 1
+
+    if { [istarget "*-*-aix*"] } {
+	set test "$prefix interrupt exitcode"
+	gdb_test_multiple "p \$_shell_exitcode" $test {
+	    -re " = void\r\n$gdb_prompt $" {
+		pass $test
+	    }
+	    -re " = 130\r\n$gdb_prompt $" {
+		# Expected for ksh88, see the comment above.
+		set signaled 0
+		pass $test
+	    }
+	}
+    } else {
+	gdb_test "p \$_shell_exitcode" " = void" "$prefix interrupt exitcode"
+    }
+
+    if { $signaled } {
+	gdb_test "p \$_shell_exitsignal" " = 2" "$prefix interrupt exitsignal"
+    } else {
+	gdb_test "p \$_shell_exitsignal" " = void" \
+	    "$prefix interrupt exitsignal"
+    }
+}
+
 gdb_exit
 gdb_start
 
@@ -37,8 +80,7 @@ gdb_test "p \$_shell_exitsignal" " = void" "shell fail exitsignal"
 # This test will not work when the shell is CMD.EXE.
 if { ! [ishost *-*-mingw*] } {
     gdb_test_no_output "! kill -2 $$"
-    gdb_test "p \$_shell_exitcode" " = void" "shell interrupt exitcode"
-    gdb_test "p \$_shell_exitsignal" " = 2" "shell interrupt exitsignal"
+    check_shell_interrupt_status "shell"
 }
 
 # Test the $_shell convenience function.
@@ -130,8 +172,7 @@ gdb_test "p \$_shell_exitsignal" " = void" "pipe fail exitsignal"
 # This test will not work when the shell is CMD.EXE.
 if { ! [ishost *-*-mingw*] } {
     gdb_test "|p 123| kill -2 $$" ""
-    gdb_test "p \$_shell_exitcode" " = void" "pipe interrupt exitcode"
-    gdb_test "p \$_shell_exitsignal" " = 2" "pipe interrupt exitsignal"
+    check_shell_interrupt_status "pipe"
 }
 
 # Error handling verifications.
-- 
2.51.2