Dropbear for iPhone

Fri Aug 27 06:40:29 WST 2010

  Matt,

First, after some experimentation, I have the following command line setup:

./configure --disable-zlib --disable-syslog --disable-lastlog --disable-shadow --disable-utmp --disable-utmpx --disable-wtmp --disable-wtmpx --disable-loginfunc --disable-pututline --disable-pututxline

Are these options correct for a strictly client only build?

make PROGRAMS=dbclient >make.log 2>&1

However, in "config.h" I still have:

337 /* Define to 1 if you have the `utmpxname' function. */
338 #define HAVE_UTMPXNAME 1
339
340 /* Define to 1 if you have the <utmpx.h> header file. */
341 #define HAVE_UTMPX_H 1
342
343 /* Define to 1 if you have the <utmp.h> header file. */
344 #define HAVE_UTMP_H 1

Shouldn't these #defines not be there (based on the "./configure" command)?

Actually, this is a problem since Xcode is telling me that these header files do not exist.

Since I do not want to change anything in config.h, I make changes in "options.h".

It looks like "includes.h" has

#include "config.h"
#include "options.h"

"options.h" is after "config.h" so I should be able to undef what I don't need.

Is this the proper procedure?

Currently, my "options.h" has:

/******************************************************************
  * Define compile-time options below - the "#ifndef DROPBEAR_XXX .... #endif"
  * parts are to allow for commandline -DDROPBEAR_XXX options etc.
  ******************************************************************/
#define TARGET_IPHONE

#if defined(TARGET_IPHONE)
     /* This should be set as part of the "compiler command line defines" but we just make sure */
     #if !defined(DROPBEAR_CLIENT)
         #define DROPBEAR_CLIENT
     #endif

     /* Define to 1 if you have the `utmpname' function. */
     #if defined(HAVE_UTMPNAME)
         #undef HAVE_UTMPNAME
     #endif

     /* Define to 1 if you have the `utmpxname' function. */
     #if defined(HAVE_UTMPXNAME)
         #undef HAVE_UTMPXNAME
     #endif

     /* Define to 1 if you have the <utmpx.h> header file. */
     #if defined(HAVE_UTMPX_H)
         #undef HAVE_UTMPX_H
     #endif

     /* Define to 1 if you have the <utmp.h> header file. */
     #if defined(HAVE_UTMP_H)
         #undef HAVE_UTMP_H
     #endif
#endif
...
...
...

One more thing. As I find small issues (as shown above) do I go ahead and post in the list?
It could get verbose.

-George
On 8/25/10 7:40 AM, Matt Johnston wrote:
> The "multi" stuff is defined in the Makefile - compile with
> "make MULTI=1" to create the multi-function binary. If
> you're only using dbclient it might be easier to just rename
> main() in cli-main.c .
>
> libtomcrypt and libtommath are built as static libraries
> that are linked to Dropbear. I think you should be able to
> run ./configure once, then add all the files including the
> "config.h" to your xcode project. I did that one time a few
> years ago and it worked OK, though I'm not sure how you'd
> run ./configure with the iphone SDK - perhaps point it at
> the relevant cross-compiling $CC?
>
> Off the top of my head I think most of dbclient should be
> threadsafe at least if there's only a single instance
> running, though there are calls to getpwnam() etc that
> could need attention. I guess you could replace the
> stdin/stdout file descriptor with a unix pipe to your main
> program as a way of talking to your UI with minimal changes
> to the dropbear code. You will also need to change the code
> in cli-chansession.c that sets up terminal control codes.
>
> Cheers,
> Matt
>
> On Tue, Aug 24, 2010 at 09:06:36PM -0400, xaos wrote:
>>   Hello everyone. This is what I'd like to do:
>>
>> In my iPhone app, I'd like to call the Dropbear client code in order to create an SSH tunnel
>> to another machine. I do not want an independent ssh command-line client.
>>
>> I will be running the client code from an iPhone thread.
>>
>> I do not want X11 forwarding or SSH compression.
>>
>> Easier said than done. I guess.
>>
>> Quick info about myself: I am a serious developer who knows a few things about iPhone,
>> Objective-C, C programming and UNIX. Been with UNIX since '84. Yes, I'm, old(er).
>>
>> So, I don't need hand holding here, just a few pointers to get me going. Naturally, I will post
>> my results as I tend to do, see my blog at: http://www.xm5design.com/
>>
>> Ok. So my initial code inspection turned out the following:
>>
>> in "cli-main.c" there is a way to start the code without a "main()" which would clash with the
>> "main()" in any iPhone app.
>>
>> This is good!
>>
>> However, the defines: "DBMULTI_dbclient" and "DROPBEAR_MULTI" are not
>> exactly clear on their meaning.
>>
>> There is a "cli_dropbear_exit" function that seems to be the central exit gate for the client code.
>> If true, this is fantastic since I don't want to Dropbear code to "exit()". I want a nice "return()"
>> which will shutdown the dropbear thread gracefully (or re-start).
>>
>> Problem: I can't really use the Makefile genned by configure since I will execute the code
>> from Xcode. Any hints?
>>
>> I tried a simple test on my OSX machine like this:
>>
>> ./configure --disable-zlib --disable-syslog --disable-lastlog
>>
>> and then:
>>
>> make PROGRAMS="dbclient">make.log 2>&1
>>
>> and I got a working client binary. I was able to ssh to another machine, etc, etc..
>>
>> However when I do: "otool -L dbclient" (otool is like like ldd)
>> I only see "/usr/lib/libSystem.B.dylib" no other lib. Does that mean
>> I don't need the libraries in "libtomcrypt" and "libtommath" for a simple client code?
>>
>> Please accept my thanks ahead of time for this. Any help is appreciated.
>>
>> -George H.

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