Use /proc/$$/stat instead of $PPID.

[chaoren]

Summary

$PPID is not available on old shells.

[chaoren]

• Add explanatory comment.

[ovyalov]

lgtm

test/tools/lldb-server/gdbremote_testcase.py

164

As for me, it might be easier to extract ppid from /proc/$$/status if it's available in old shells - but it's up to you.

test/tools/lldb-server/gdbremote_testcase.py

def init_llgs_test(self, use_named_pipe=True):
                         m += ">>> %s\n" % str(err).strip()
                     m += ">>> %s\n" % (shell_cmd.GetOutput() or
                                        "Command generated no output.")
                     raise Exception(m)
                 return shell_cmd.GetOutput().strip()
             # Remote platforms don't support named pipe based port negotiation
             use_named_pipe = False
 
-            pid = run_shell_cmd("echo $PPID")
+            # Grab the ppid from /proc/[shell pid]/stat
+            shell_stat = run_shell_cmd("cat /proc/$$/stat")
+            # [pid] ([executable]) [state] [*ppid*]
+            pid = re.match(r"^\d+ \(.+\) . (\d+)", shell_stat).group(1)
             ls_output = run_shell_cmd("ls -l /proc/%s/exe" % pid)
             exe = ls_output.split()[-1]
 
             # If the binary has been deleted, the link name has " (deleted)" appended.
             # Remove if it's there.
             self.debug_monitor_exe = re.sub(r' \(deleted\)$', '', exe)
         else:
             self.debug_monitor_exe = get_lldb_server_exe()