[patch] fix the bug of conflict of -c and -x option

[patch] fix the bug of conflict of -c and -x option

[Lai Jiangshan]

hi, all

using the following command to test target(), we can find that
the return value of target() is the pid of "readlink /proc/self",
but not 1234 as expected. Obviously, the -c and -x options are
conflict! pid specified by -x option will be overwritten if the -c
option is also specified.

$ stap -c "readlink /proc/self" -x 1234 -e 'probe begin{printf("target()=%d\n",target())}'
19681
target()=19681

the man page of stap says nothing about the conflict of -c and -x.

I think it will be better if the following patch can be applied. 

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>

diff -Nur systemtap-20070818/main.cxx systemtap-20070818-new/main.cxx
--- systemtap-20070818/main.cxx	2007-08-15 00:29:40.000000000 +0900
+++ systemtap-20070818-new/main.cxx	2007-08-20 14:24:36.000000000 +0900
@@ -448,6 +448,12 @@
       usage (s, 1);
     }
 
+  if((s.cmd != "") && (s.target_pid))
+    {
+      cerr << "You can't specify -c and -x options together." <<endl;
+      usage (s, 1);
+    }
+
   if (s.last_pass > 4 && release_changed)
     {
       if (s.verbose)
diff -Nur systemtap-20070818/runtime/staprun/common.c systemtap-20070818-new/runtime/staprun/common.c
--- systemtap-20070818/runtime/staprun/common.c	2007-08-15 00:23:59.000000000 +0900
+++ systemtap-20070818-new/runtime/staprun/common.c	2007-08-20 14:44:16.000000000 +0900
@@ -104,6 +104,11 @@
 		    "option only has an effect when the module is inserted.\n");
 		usage(argv[0]);
 	}
+
+	if (target_cmd && target_pid) {
+		err("You can't specify the '-c' and '-x' options together.\n");
+		usage(argv[0]);
+	}
 }
 
 void usage(char *prog)

Re: [patch] fix the bug of conflict of -c and -x option

[David Smith]

Lai Jiangshan wrote:
> hi, all
> 
> using the following command to test target(), we can find that
> the return value of target() is the pid of "readlink /proc/self",
> but not 1234 as expected. Obviously, the -c and -x options are
> conflict! pid specified by -x option will be overwritten if the -c
> option is also specified.
> 
> $ stap -c "readlink /proc/self" -x 1234 -e 'probe 
> begin{printf("target()=%d\n",target())}'
> 19681
> target()=19681
> 
> the man page of stap says nothing about the conflict of -c and -x.
> 
> I think it will be better if the following patch can be applied.
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> 

... patch deleted ...

Lai,

Thanks for the patch - I've committed it.  I'll also be adding two 
testcases to see this code gets exercised.

-- 
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
256.217.0141 (direct)
256.837.0057 (fax)