Tuesday, September 29, 2009

Solaris: Which process is associated with a socket connection?

Consider the following real world scenario (copied from an e-mail message that I got from one of our partners):

[...] one process is waiting for a very long time in a send system call. It is sending on a valid fd but the question we have is that, is there any way to find who is on the other end of that fd? We want to know to which process is that message being sent to. [...]

Here is how I proceed in finding the other end of the socket, and the state of the socket connection with Mozilla's Thunderbird mail client in one end of the socket connection:

Get the process id of the application

% prstat PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP 22385 mandalik 180M 64M sleep 49 0 0:05:15 0.1% thunderbird-bin/5

Run pfiles on the pid - it prints a list of open files including open sockets (pfiles is the Solaris supported equivalent of lsof utility).

% pfiles 2238522385: /usr/lib/thunderbird/thunderbird-bin -UILocale C -contentLocale C Current rlimit: 512 file descriptors ... ... 33: S_IFSOCK mode:0666 dev:280,0 ino:31544 uid:0 gid:0 size:0 O_RDWR
O_NONBLOCK SOCK_STREAM SO_SNDBUF(49152),SO_RCVBUF(49640) sockname: AF_INET 192.168.1.2 port: 60364 peername: AF_INET 192.18.39.10 port: 993 ... ...

Locate the socket id and the corresponding sockname/port#, peername/port# in the output of pfiles pid (see step #2).

Here my assumption is that I know the socket id I'm interested in. In the above output, 33 is the socket id. One end of the socket is bound to port 60364 on the local host 192.168.1.2; and the other end of the socket is bound to port 993 on the remote host 192.18.39.10.

Run netstat -a
egrep "
(get the port numbers from step 3); and check the state of the socket connection. If you see anything other than ESTABLISHED, it indicates trouble.

% netstat -a
egrep "60364
993"solaris-devx-iprb0.60364 mail-sfbay.sun.com.993 48460 0 49640 0 ESTABLISHED

If you want to see the host names in numbers (IP addresses), run netstat with option -n.

% netstat -an
egrep "60364
993"192.168.1.2.60364 192.18.39.10.993 49559 0 49640 0 ESTABLISHED

Now since we know both ends of the socket, we can easily get the state of the socket connection at the other end by running netstat -an
egrep '

If the state of the socket connection is CLOSE_WAIT, have a look at the following diagnosis: CPU hog with connections in CLOSE_WAIT.

Finally to answer ... which process is that message being sent to ... part of the original question:

Follow the above steps and find the remote host (or IP) and remote port number. To find the corresponding process id on the remote machine to which the other half of the socket belongs to, do the following:

Login as root user on the remote host.

cd /proc

Run pfiles *
egrep "^[0-9]
sockname" > /tmp/pfiles.txt.

vi /tmp/pfiles.txt and search for the port number. If you scroll few lines up, you can see the process ID, name of the process along with its argument(s).

Thursday, September 24, 2009

Find Duplicate records in Oracle

SELECT COL_TO_CHECK, COUNT(COL_TO_CHECK)
FROM TABLE_NAME
GROUP BY COL_TO_CHECK
HAVING COUNT(COL_TO_CHECK) > 1

Thursday, September 10, 2009

Change network setting from DHCP to Static

[root@host ~]# ifconfig


eth0 Link encap:Ethernet HWaddr 00:D0:BC:08:09:BC

inet addr:70.238.17.69 Bcast:255.255.255.255 Mask:255.255.255.248

inet6 addr: fe80::2d0:b7ff:fe08:9bb/64 Scope:Link

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:7174 errors:0 dropped:0 overruns:0 frame:0

TX packets:2305 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:5339910 (5.0 MiB) TX bytes:170109 (166.1 KiB)



lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

inet6 addr: ::1/128 Scope:Host

UP LOOPBACK RUNNING MTU:16436 Metric:1

RX packets:34 errors:0 dropped:0 overruns:0 frame:0

TX packets:34 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:4275 (4.1 KiB) TX bytes:4275 (4.1 KiB)




cat /etc/hosts


# Do not remove the following line, or various programs

# that require network functionality will fail.

127.0.0.1 myhost.mydomain.com myhost localhost.localdomain localhost

192.168.1.100 myhost.mydomain.com myhost

::1 localhost6.localdomain6 localhost6







cat /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0

BOOTPROTO=dhcp

HWADDR=00:D0:B7:08:09:BB

ONBOOT=yes







Change above file to below one

OUTPUT for static IP (example)

#

# File: ifcfg-eth0

#

DEVICE=eth0

IPADDR=192.168.1.100

NETMASK=255.255.255.0

BOOTPROTO=static

ONBOOT=yes

#

# The following settings are optional

#

BROADCAST=192.168.1.255

NETWORK=192.168.1.0

TYPE=Ethernet









Also confirm below files have correct entry

cat /etc/sysconfig/network

NETWORKING=yes

HOSTNAME=myhost

GATEWAY=192.168.1.1









Now restart network

/etc/rc.d/init.d/network restart





Check all with below command

ethtool eth0