XP_CMDSHELL how to capture return value?

Question

I need to write an console application that returns a return code that can be captured through xp_cmdshell.

I started with c# code as follows,

class Program
    {
        static int Main(string[] args)
        {
            //make sure the correct number of arguments are being passed.
            if (args.Length !=5)
            {
                Console.WriteLine("not thr right number of args. \nUsage SFTPUploadFile <host> <port> <username> <password> <localFilePath>");
                return 1;
            }

            return 0;        
        }

    }

The XP_cmdhsell I am using some code I found

declare  @rc int

create table #output (id int identity(1,1), output nvarchar(255) null)
insert #output (output) exec @rc = master..xp_cmdshell 'd:\FILENAME PARA1 PARA2 PARA3 PARA4 PARA5'
select * from #output where output is not null order by id
drop table #output

but when I run my xp_cmdshell, I just get null. Shouldn't I be getting 1 or 0?

Thanks

You probably should add your call to `xp_cmdshell` and how you verify its value. — Alexei Levenkov, Jun 20 '13 at 02:06

score 0 · Answer 1 · answered Jun 20 '13 at 02:41

It looks like your program checks to see whether or not there are 5 parameters, and does nothing (returns 0) if there are.

The xp_cmdshell command, in turn, supplies all the parameters. xp_cmdshell will return NULL if it does not receive any output.

If you changed the code to read something like this:

class Program
    {
        static int Main(string[] args)
        {
            //make sure the correct number of arguments are being passed.
            if (args.Length !=5)
            {
                Console.WriteLine("not thr right number of args. \nUsage SFTPUploadFile <host> <port> <username> <password> <localFilePath>");
                return 1;
            }

            Console.WriteLine("You had the right number of args.");
            return 0;        
        }

    }

(Alternatively, you can do Console.WriteLine("0"); and Console.WriteLine("1"); if you really want 0 or 1 back.)

You'd get back You had the right number of args.. This is because return 0; and return 1; do not print anything out to the console, which is what xp_cmdshell will send back to the client.

You can prove this by doing EXEC master..xp_cmdshell 'cd ..' ... it's a command that does not return results. On the other hand, EXEC master..xp_cmdshell 'dir *.exe' will return you the directory contents, as this is what would be output (or written) to the console.

on my local it actually outputs the success or error messages. But on the production server it just returns null or both cases... could there be a permission issue? — user2206329, Jun 20 '13 at 03:47
You're right - xp_cmdshell runs under your username / password when attempting to run (and you're a sysadmin), otherwise it will use the proxy user. You (or the proxy user) may or may not have the right permissions on the server in production to see a result. More can be found [here](http://msdn.microsoft.com/en-us/library/ms175046.aspx) — brazilianldsjaguar, Jun 20 '13 at 14:11

XP_CMDSHELL how to capture return value?

1 Answers1