script compilation fails at 'Pass 4'

script compilation fails at 'Pass 4'

[Mehul Choube]

Hi,

Whenever a syscall.connect returns I want to print the socket name (getsockname())

Error:

======= run start =======

[root@rhel5-stap stps]# stap -g strace-connect.stp -c "curl www.google.com"
Pass 4: compilation failed.  Try again with another '--vp 0001' option.

[root@rhel5-stap stps]# stap -g --vp 0001 strace-connect.stp -c "curl www.google.com"
Pass 4: compiled C into "stap_b7800dfc97ca81afbd4921aaa452d856_6437.ko" in 740usr/190sys/932real ms.
Pass 4: compilation failed.  Try again with another '--vp 0001' option.

[root@rhel5-stap ~]# uname -a
Linux rhel5-stap 2.6.18-164.el5 #1 SMP Tue Aug 18 15:51:48 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

======= run end =======

The script and the C code is at: http://pastebin.com/ZspDG6qx



Thanks,
Mehul

Re: script compilation fails at 'Pass 4'

[David Smith]

On 12/06/2012 03:38 AM, Mehul Choube wrote:
> Hi,
> 
> Whenever a syscall.connect returns I want to print the socket name (getsockname())
> 
> Error:
> 
> ======= run start =======
> 
> [root@rhel5-stap stps]# stap -g strace-connect.stp -c "curl www.google.com"
> Pass 4: compilation failed.  Try again with another '--vp 0001' option.
> 
> [root@rhel5-stap stps]# stap -g --vp 0001 strace-connect.stp -c "curl www.google.com"
> Pass 4: compiled C into "stap_b7800dfc97ca81afbd4921aaa452d856_6437.ko" in 740usr/190sys/932real ms.
> Pass 4: compilation failed.  Try again with another '--vp 0001' option.
> 
> [root@rhel5-stap ~]# uname -a
> Linux rhel5-stap 2.6.18-164.el5 #1 SMP Tue Aug 18 15:51:48 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
> 
> ======= run end =======
> 
> The script and the C code is at: http://pastebin.com/ZspDG6qx

Mehul,

I'm not sure why you aren't getting any error messages out of stap. What
version of systemtap are you running?

Here's what I get with systemtap HEAD:

====
# stap -gv ./strace-connect.stp -c "curl www.google.com"
Checking "/lib/modules/2.6.18-308.20.1.el5/build/System.map" failed with
error: No such file or directory
Ensure kernel development headers & makefiles are installed
Pass 1: parsed user script and 90 library script(s) using
148624virt/23228res/2904shr/21132data kb, in 180usr/20sys/202real ms.
Pass 2: analyzed script: 1 probe(s), 2 function(s), 3 embed(s), 0
global(s) using 226460virt/81232res/45132shr/36912data kb, in
370usr/20sys/394real ms.
Pass 3: translated to C into
"/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c" using
226460virt/81476res/45376shr/36912data kb, in 10usr/0sys/8real ms.
/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c:22:20:
error: stdlib.h: No such file or directory
/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c:23:24:
error: sys/socket.h: No such file or directory
/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c: In
function ‘function_sockname’:
/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c:501:
error: implicit declaration of function ‘malloc’
cc1: warnings being treated as errors
/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c:501:
warning: incompatible implicit declaration of built-in function ‘malloc’
/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c:501:
error: invalid application of ‘sizeof’ to incomplete type ‘struct sockaddr’
/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.c:502:
error: expected ‘,’ or ‘;’ before ‘if’
make[1]: ***
[/tmp/stapg3uHUN/stap_548b6f815eca69cfd5a759e9b2e12233_7447_src.o] Error 1
make: *** [_module_/tmp/stapg3uHUN] Error 2
WARNING: kbuild exited with status: 2
Pass 4: compiled C into "stap_548b6f815eca69cfd5a759e9b2e12233_7447.ko"
in 380usr/190sys/588real ms.
Pass 4: compilation failed.  Try again with another '--vp 0001' option.
====

There are several misconceptions with your script. The main one being
that the embedded C code in your script isn't user code, it is kernel
code. So, for instance you can't call malloc(), header files don't come
from /usr/include, etc.

Perhaps you could back up a bit and tell us what you are really trying
to do?

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

RE: script compilation fails at 'Pass 4'

[Mehul Choube]

On Thu, 6 Dec 2012, David Smith wrote:
>
> Perhaps you could back up a bit and tell us what you are really trying
> to do?

our product have ~60 daemons running plus occasionally we spawn ephemeral
processes. Using systemtap I want to find out who connects to whom for
servicing a request.

output something like:

A (pid) <-- Socket --> B (pid)
B (pid) <-- Shared memory --> D (pid)
D (pid) <-- Message queue --> C (pid)
and so on...

I want to match local address+localport from connect() to remote
address+remote port in accept().



Thanks,
Mehul

Re: script compilation fails at 'Pass 4'

[Frank Ch. Eigler]

Mehul_Choube wrote:

> http://pastebin.com/vyKHBGd0

sockname() can't work like that.  Systemtap embedded-C code runs
within the kernel, and can't call userspace glibc functions or
system calls like that.

Try instead: 

########################################################################
function print_fd(fd) {
         task = task_current()
         sock = task_file_handle_socket(task,fd)
	 if (sock) {
            fam = socket_family(sock)
            if (fam == %{ AF_INET %}) {
	       printf("%s[%d] fd %d: %s\n", execname(), tid(), fd,
                      socket_ipv4_sockname(sock))
               return 0
            } /* other cases as per pfiles.stp */
         }
}

probe syscall.connect.return {
      if ($return >= 0) print_fd($return)
}


/* the rest verbatim from pfiles.stp */

%{
#include <linux/file.h>
#include <net/sock.h>
#include <linux/un.h>
#include <linux/tcp.h>
#include <linux/in.h>
%}

function task_file_handle_socket:long (task:long, fd:long) %{ /* pure */
        struct task_struct *p = (struct task_struct *)((long)STAP_ARG_task);
	struct files_struct *files;
        struct file *filp;
        struct dentry *dentry;
        struct inode *inode;

        rcu_read_lock();
        if ((files = kread(&p->files)) &&
            (filp = fcheck_files(files, STAP_ARG_fd)) &&
            (dentry = kread(&filp->f_dentry)) &&
            (inode = kread(&filp->f_dentry->d_inode))) {
                if (S_ISSOCK(kread(&inode->i_mode)))
                        STAP_RETVALUE = (long)SOCKET_I(inode);
        }

        CATCH_DEREF_FAULT();
        rcu_read_unlock();
%}

function socket_family:long (sock:long) %{ /* pure */
	struct socket *sock = (struct socket *)((long)STAP_ARG_sock);
        const struct proto_ops *ops = kread(&sock->ops);
        STAP_RETVALUE = (long)kread(&ops->family);
        CATCH_DEREF_FAULT();
%}

function socket_ipv4_sockname:string (sock:long) %{ /* pure */
        struct socket *sock = (struct socket *)((long)STAP_ARG_sock);
        const struct proto_ops *ops = kread(&sock->ops);
        struct sockaddr_in in_addr;
        __be32 addr, port;
        int err, len;

	err = ops->getname (sock, (struct sockaddr*)(&in_addr), &len, 0);
        if (!err) {
                addr = in_addr.sin_addr.s_addr;
                port = htons(in_addr.sin_port);
		snprintf(STAP_RETVALUE, MAXSTRINGLEN,
                        "        sockname: AF_INET " NIPQUAD_FMT "  port: %d",
	                NIPQUAD(addr), port);
        }
        CATCH_DEREF_FAULT();
%}

RE: script compilation fails at 'Pass 4'

[Mehul Choube]

On Thu, 6 Dec 2012, Frank Ch. Eigler wrote:

>
> Mehul_Choube wrote:
>
>> http://pastebin.com/vyKHBGd0
>
> sockname() can't work like that.  Systemtap embedded-C code runs
> within the kernel, and can't call userspace glibc functions or
> system calls like that.
>
> Try instead:
>
> ########################################################################
> function print_fd(fd) {
>         task = task_current()
>         sock = task_file_handle_socket(task,fd)
> 	 if (sock) {
>            fam = socket_family(sock)
>            if (fam == %{ AF_INET %}) {
> 	       printf("%s[%d] fd %d: %s\n", execname(), tid(), fd,
>                      socket_ipv4_sockname(sock))
>               return 0
>            } /* other cases as per pfiles.stp */
>         }
> }
>
> probe syscall.connect.return {
>      if ($return >= 0) print_fd($return)
> }
>
>
> /* the rest verbatim from pfiles.stp */
>
> %{
> #include <linux/file.h>
> #include <net/sock.h>
> #include <linux/un.h>
> #include <linux/tcp.h>
> #include <linux/in.h>
> %}
>
> function task_file_handle_socket:long (task:long, fd:long) %{ /* pure */
>        struct task_struct *p = (struct task_struct *)((long)STAP_ARG_task);
> 	struct files_struct *files;
>        struct file *filp;
>        struct dentry *dentry;
>        struct inode *inode;
>
>        rcu_read_lock();
>        if ((files = kread(&p->files)) &&
>            (filp = fcheck_files(files, STAP_ARG_fd)) &&
>            (dentry = kread(&filp->f_dentry)) &&
>            (inode = kread(&filp->f_dentry->d_inode))) {
>                if (S_ISSOCK(kread(&inode->i_mode)))
>                        STAP_RETVALUE = (long)SOCKET_I(inode);
>        }
>
>        CATCH_DEREF_FAULT();
>        rcu_read_unlock();
> %}
>
> function socket_family:long (sock:long) %{ /* pure */
> 	struct socket *sock = (struct socket *)((long)STAP_ARG_sock);
>        const struct proto_ops *ops = kread(&sock->ops);
>        STAP_RETVALUE = (long)kread(&ops->family);
>        CATCH_DEREF_FAULT();
> %}
>
> function socket_ipv4_sockname:string (sock:long) %{ /* pure */
>        struct socket *sock = (struct socket *)((long)STAP_ARG_sock);
>        const struct proto_ops *ops = kread(&sock->ops);
>        struct sockaddr_in in_addr;
>        __be32 addr, port;
>        int err, len;
>
> 	err = ops->getname (sock, (struct sockaddr*)(&in_addr), &len, 0);
>        if (!err) {
>                addr = in_addr.sin_addr.s_addr;
>                port = htons(in_addr.sin_port);
> 		snprintf(STAP_RETVALUE, MAXSTRINGLEN,
>                        "        sockname: AF_INET " NIPQUAD_FMT "  port: %d",
> 	                NIPQUAD(addr), port);
>        }
>        CATCH_DEREF_FAULT();
> %}
>
>

Now it fails with:
error: 'STAP_ARG_sock' undeclared (first use in this function)

please check: http://pastebin.com/wvZFu02g



Thanks,
Mehul

Re: script compilation fails at 'Pass 4'

[Frank Ch. Eigler]

Mehul Choube <Mehul_Choube@symantec.com> writes:

> [...]
> Now it fails with:
> error: 'STAP_ARG_sock' undeclared (first use in this function)

OK, so you must be running a systemtap version older than 1.8.  In
that case, you would need to use THIS->sock instead of STAP_ARG_sock
and THIS->__retvalue for STAP_RETVALUE etc. in the embedded-C blocks.

You might also need to copy the NIPQUAD* related embedded-C block from
<http://sourceware.org/systemtap/examples/process/pfiles.stp>.

- FChE