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telnet hangs

Posted by kannarv1 (sivga1), 11 May 2007
hi
here is the expect script to telnet into a system .it succesfully telnets into the systembut when it matches

"Escape character is '^]'.^M" it hangs.. not sure why this happenning .

expect output

. 10.55.192.9 is alive ...
$ /bin/telnet 10.55.192.9^M
Trying 10.55.192.9...^M
Connected to 10.55.192.9.^M
Escape character is '^]'.^M

/bin/telnet 10.55.192.9^M
/bin/telnet 10.55.192.9^M
/bin/telnet 10.55.192.9^M
/bin/telnet 10.55.192.9^M


expect script

proc opentelnet{ tipaddr tPrompt tLogin tPasswd } {
     global      TELNET SESSION_CONNECTED TIMEOUT

     set func "opentelnet"
     
     set timeout $TIMEOUT
     send -- "$TELNET $tipaddr \r"
     #spawn $TELNET $tipaddr
       
     while (1) {
           expect {
                 "Last *\n"  {
                       continue
                 }
                 "ogin: "  {
                       send -- "$tLogin\r"
                       dbgLog 5 $func  "1. Send login name $tLogin ..."
                       continue
                 }
                 "assword: "  {
                       send -- "$tPasswd\r"
                       dbgLog 5 $func  "2. Sent passwd name ..."
                       break
                 }
                 "unknown host" {
                       errLog $func   "3. Unknown host $thost"
                       return -1
                 }
                 "*incorrect input"  {
                           errLog $func   "4. Login failed (invalid login name or passwd) ... "
                       return -1
                 }
                 "*incorrect"  {
                           errLog $func   "5. Login failed (invalid login name or passwd) ..."
                       return -1
                 }
                 timeout {
                           errLog $func   "6. Failed to establish telnet session with tipaddr ... host: $ipaddr"
                       return -1
                 }
             }
     }

     return 0
}




can you any one tell me why is this happenning.I even had a return when i matched Escape character is but dint help.

thnaks for all the help



Posted by admin (Graham Ellis), 11 May 2007
As far as I can see, you "continue" when you get Last.... and so thet goes back into expecting more.  nothing else matched, so you get a timeout ....

Since all the resopnses come in order, why not write a series of individual expects rather than putting them all into an infinite loop - much cleaner, easier to follow, easier to debug!

Posted by kannarv1 (sivga1), 11 May 2007
thanks graham even if i match and did continue it dint work th eproblem is

send: sending "/bin/telnet 10.55.192.9\r" to { exp28 }

expect: does "" (spawn_id exp2 match glob pattern "*ogin*"? no
"unknown host"? no
"*assword*"? no
"*]: "? no
"*incorrect input"? no
"*Unknown command"? no
"*Incomplete command"? no
"*Invalid input"? no
"*incorrect"? no

$ /bin/telnet 10.55.192.9

expect: does "$ /bin/telnet 10.55.192.9\r\n" (spawn_id exp2 match glob pattern "*ogin*"? no
"unknown host"? no
"*assword*"? no
"*]: "? no
"*incorrect input"? no
"*Unknown command"? no
"*Incomplete command"? no
expect: does "$ /bin/telnet 10.55.192.9\r\nTrying 10.55.192.9...\r\n" (spawn_id exp2 match glob pattern "*ogin*"? no
"unknown host"? no
"*assword*"? no
"*]: "? no
"*incorrect input"? no
"*Unknown command"? no
"*Incomplete command"? no
"*Invalid input"? no
"*incorrect"? no

Connected to 10.55.192.9.
Escape character is '^]'.

expect: does "$ /bin/telnet 10.55.192.9\r\nTrying 10.55.192.9...\r\nConnected to 10.55.192.9.\r\nEscape character is '^]'.\r\n" (spawn_id exp2 match glob pattern "*ogin*"? no
"unknown host"? no
"*assword*"? no
"*]: "? no
"*incorrect input"? no
"*Unknown command"? no
"*Incomplete command"? no
"*Invalid input"? no
"*incorrect"? no




nConnected to 10.55.192.9.\r\nEscape character is '^]

device does not send the login prompt.. so the expect scripts times out ..

but i can login to the device and everything works fine .

iam invoking the script froma a C program ..when i invoke the script seperately its fine ..


not sure why the login prompty is not coming





Posted by kannarv1 (sivga1), 11 May 2007
why does it hang after
hangs after the "Escape character is '^]'"

iam runningthe script on solaris

Posted by admin (Graham Ellis), 12 May 2007
Err ... the log doesn't look like it comes from quite the same code as the source you posted earlier.  So it's kinda hard to look for the bug.  I do note that you seem (from the log) to be looking for the ^] FOLLOWED BY A SPACE which isn't there on what telnet sends, and that would cause a hangup ...



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