Guard against killing unrelated processes in amd64-disp-step.exp

When testing current gdb trunk on Solaris/amd64, the whole session was
reliably terminated by make check.  I could trace this to the following
entry in gdb.arch/amd64-disp-step/gdb.log:

FAIL: gdb.arch/amd64-disp-step.exp: add into rcx: send_signal=on: get
inferior pid
Executing on target: kill -ALRM -1    (timeout = 300)
builtin_spawn -ignore SIGHUP kill -ALRM -1

If $inferior_pid doesn't refer to a single process for some reason, this
kill would terminate either a process group or the whole session.

This patch avoids this by ensuring that the pid arg is positive.

Tested on amd64-pc-solaris2.11 and x86_64-pc-linux-gnu.

Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>

diff --git a/gdb/testsuite/gdb.arch/amd64-disp-step.exp b/gdb/testsuite/gdb.arch/amd64-disp-step.exp
index 0919e71..79e752c 100644 (file)
--- a/gdb/testsuite/gdb.arch/amd64-disp-step.exp
+++ b/gdb/testsuite/gdb.arch/amd64-disp-step.exp
@@ -222,7 +222,12 @@ proc rip_test { reg test_start_label test_end_label signal_modes } {
            # If we use 'signal' to send the signal GDB doesn't actually do
            # the displaced step, but instead just delivers the signal.
            set inferior_pid [get_inferior_pid]
-           remote_exec target "kill -ALRM $inferior_pid"
+           # Ensure that $inferior_pid refers to a single process.
+           gdb_assert {[expr $inferior_pid > 0]} \
+               "check for a sane inferior pid"
+           if {$inferior_pid > 0} {
+               remote_exec target "kill -ALRM $inferior_pid"
+           }
        }
 
        gdb_test "continue" \