This entry is mostly for newcomers to Solaris/OpenSolaris from UNIX-like systems. When I had been taught about signal() and sigaction() my understanding was that sigaction() is just a superset of signal() and also POSIX conformant but otherwise they accomplish the same thing. This is indeed the case for some of UNIX-like operating systems. In Solaris, as I only recently discovered (to my dismay :)), it's different.

Consider the following code (please ignore the fact it's not strictly checking return values and that the signal handler is not safe):

#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>

void sig_handler(int s) {
	printf("Got signal! Sleeping.\n");

	sleep(10);

        printf("returning from signal handler\n");
}

int main(void) {
        struct sigaction s_action;

	printf("Setting signal handler: ");
#ifdef POSIX_SIGNALS
	printf("sigaction\n");
	(void) sigemptyset(&s_action.sa_mask);
	s_action.sa_handler = sig_handler;
        s_action.sa_flags = 0;
	(void) sigaction(SIGHUP, &s_action, (struct sigaction *) NULL);
#else
	printf("signal\n");
	signal(SIGHUP, sig_handler);
#endif

	printf("Waiting for signal\n");
	while(1)
		pause();

	return (0);
}

Now try to compile and run with and without the -DPOSIX_SIGNALS and send 2 SIGHUP signals to the process within the 10 seconds window (so the second signal is received while the signal handler is still running). With sigaction(), the signal will be caught by the handler in both of the cases. With signal() however, the second signal will cause the process to exit. This is because kernel will reset the signal handler to default upon receiving the signal for the first time. This is described in the signal(3C) man page in a somewhat hidden sentence inside the second paragraph (it really pays out to read man pages slowly and with attention to detail):

     If signal()  is
     used,  disp  is  the address of a signal handler, and sig is
     not  SIGILL, SIGTRAP, or  SIGPWR, the system first sets  the
     signal's disposition to  SIG_DFL before executing the signal
     handler.

The sigaction(2) man page has this section:

     SA_RESETHAND    If set and the signal is caught, the  dispo-
                     sition of the signal is reset to SIG_DFL and
                     the signal will not be blocked on  entry  to
                     the  signal  handler  (SIGILL,  SIGTRAP, and
                     SIGPWR cannot be  automatically  reset  when
                     delivered; the system silently enforces this
                     restriction).

sigaction() does not set the flag by default which results in the different behavior. I found out that this behavior has been present since Solaris 2.0 or so.

In fact, signal() routine from libc is implemented via sigaction(). From $SRC/lib/libc/port/sys/signal.c:

     58 /*
     59  * SVr3.x signal compatibility routines. They are now
     60  * implemented as library routines instead of system
     61  * calls.
     62  */
     63 
     64 void(*
     65 signal(int sig, void(*func)(int)))(int)
     66 {
     67 	struct sigaction nact;
     68 	struct sigaction oact;
     69 
     70 	CHECK_SIG(sig, SIG_ERR);
     71 
     72 	nact.sa_handler = func;
     73 	nact.sa_flags = SA_RESETHAND|SA_NODEFER;
     74 	(void) sigemptyset(&nact.sa_mask);
     75 
     76 	/*
     77 	 * Pay special attention if sig is SIGCHLD and
     78 	 * the disposition is SIG_IGN, per sysV signal man page.
     79 	 */
     80 	if (sig == SIGCHLD) {
     81 		nact.sa_flags |= SA_NOCLDSTOP;
     82 		if (func == SIG_IGN)
     83 			nact.sa_flags |= SA_NOCLDWAIT;
     84 	}
     85 
     86 	if (STOPDEFAULT(sig))
     87 		nact.sa_flags |= SA_RESTART;
     88 
     89 	if (sigaction(sig, &nact, &oact) < 0)
     90 		return (SIG_ERR);
     91 
     92 	return (oact.sa_handler);
     93 }

I am pretty sure that the SA_RESETHAND flag is set in signal() in order to preserve backwards compatibility.

This means that to solve this problem with signal(), one should set the signal handler again in the signal handler itself. However, this is not a complete solution since there is still a window where the signal can be delivered and the handler is set to SIG_DFL - the default handler which is exit in case of SIGHUP as the signal.h(3HEAD) man page explains in really useful table:

          Name        Value   Default                    Event
     SIGHUP           1       Exit       Hangup (see termio(7I))
     ...

Now let's look at FreeBSD. Its SIGNAL(3) man page contains this separate paragraph:

     The handled signal is unblocked when the function returns and the process
     continues from where it left off when the signal occurred.  Unlike previ-
     ous signal facilities, the handler func() remains installed after a sig-
     nal has been delivered.

The second sentence is actually printed in bold letters. I also tried on Linux and NetBSD and the behavior is the same as in FreeBSD.

So, to conclude all of the above: using signal() is really not portable.

Recently I needed to test a bug fix in in.iked(1M) (should say libike.so with which in.iked is linked) after which the daemon should respond to IKEv2 requests with Notification message telling the peer to fall back to IKEv1 (previously it did not respond to IKEv2 packets at all). This can be tested by:

• installing a OS instance which supports IKEv2 and initiating from there
• writing a simple program (C/Perl/etc.) which will construct the UDP payload

Surely, there should be easier way how to send a UDP paket with arbitrary (in my case ISAKMP) payload. It turns out this is very easy to do just from command line with nc(1) which is available in OpenSolaris (install it via 'pkg install SUNWnetcat'). Let's try to send some garbage first to see if it works:

perl -e 'print "\x41\x41";' | nc -u rpe-foo.czech 500

Yep, tshark(1) (in OpenSolaris shipped by default with Wireshark) reports an IKE packet, malformed one (which is not surprising):

Capturing on eri0
  0.000000 10.18.144.12 -> 10.18.144.11 ISAKMP [Malformed Packet]

0000  00 0a e4 2f 61 eb 00 03 ba 4e 3d 38 08 00 45 00   .../a....N=8..E.
0010  00 1e 26 98 40 00 ff 11 20 fb 0a 12 90 0c 0a 12   ..&.@... .......
0020  90 0b e2 66 01 f4 00 0a 34 57 41 41               ...f....4WAA

Our two A's are there just after the UDP header (Ethernet header 14 bytes, IP header 20 bytes, UDP 8 bytes, in sum 42 bytes and our 2 bytes are just after first 8 bytes on 3rd line).

With that we can go and construct IKEv1 packet first to see if the daemon will react upon it. We will need to construct the payload which is a IKEv1 header. IKEv1 is defined in RFC 2409 (The Internet Key Exchange (IKE)). IKEv1 uses ISAKMP header definition so we need to look into RFC 2408 (Internet Security Association and Key Management Protocol (ISAKMP)) for the actual header definition. It's there in section 3.1:

                         1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    !                          Initiator                            !
    !                            Cookie                             !
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    !                          Responder                            !
    !                            Cookie                             !
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    !  Next Payload ! MjVer ! MnVer ! Exchange Type !     Flags     !
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    !                          Message ID                           !
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    !                            Length                             !
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

I'd like to construct a packet which resembles first packet sent by IKEv1 Initiator. So, our packet code (similar to shell code) will look like this (without thinking too much of what should the values look like):

• Initiator's cookie, must not be zero

      \x11\x22\x33\x44\x55\x66\x77\x88
  

• Responder's cookie, must be zero in the initial packet from Initiator

      \x00\x00\x00\x00\x00\x00\x00\x00
  

• next payload, let's try 0 first

      \x00
  

• Major and Minor Version (4 bits each)

      \x10
  

• Exchange Type

                              Exchange Type      Value
                           NONE                    0
                           Base                    1
                           Identity Protection     2
                           Authentication Only     3
                           Aggressive              4
                           Informational           5
                           ISAKMP Future Use     6 - 31
                           DOI Specific Use     32 - 239
                           Private Use         240 - 255
  

  So let's try Base first:

      \x01
  

• Flags (Initiator)

      \x00
  

• Message ID

      \x66\x66\x66\x66
  

• Length

      \x28
  

We need to massage our packet code into command line. The code:

 \x11\x22\x33\x44\x55\x66\x77\x88
 \x00\x00\x00\x00\x00\x00\x00\x00
 \x00
 \x10
 \x01
 \x00
 \x66\x66\x66\x66
 \x28

We want source port to be 500 as well because of section 2.5.1 in RFC 2408 so use the -p option (this requires the net_privaddr privilege so either become root or use pfexec(1)). Also, we do not need to wait for the response so use -w option:

perl -e 'print "\x11\x22\x33\x44\x55\x66\x77\x88\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x01\x00\x66\x66\x66\x66\x28";' \
    | nc -w 1 -p 500 -u rpe-foo.czech 500

The packet was received but there was no reply and tshark still considers this as Malformed Packet. Let's check the header again - oh yeah, the Length field has 4 bytes, not just one. Let's try again:

perl -e 'print "\x11\x22\x33\x44\x55\x66\x77\x88\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x01\x00\x66\x66\x66\x66\x28\x00\x00\x00";' \
    | nc -w 1 -p 500 -u rpe-foo.czech 500

Okay, this is our Base exchange but still not response:

294.029154 10.18.144.12 -> 10.18.144.11 ISAKMP Base

0000  00 0a e4 2f 61 eb 00 03 ba 4e 3d 38 08 00 45 00   .../a....N=8..E.
0010  00 38 26 a7 40 00 ff 11 20 d2 0a 12 90 0c 0a 12   .8&.@... .......
0020  90 0b 01 f4 01 f4 00 24 34 71 11 22 33 44 55 66   .......$4q."3DUf
0030  77 88 00 00 00 00 00 00 00 00 00 10 01 00 66 66   w.............ff
0040  66 66 28 00 00 00                    

Let's try something more provocative and set the Exchange type to Identity protection:

perl -e 'print "\x11\x22\x33\x44\x55\x66\x77\x88\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x02\x00\x66\x66\x66\x66\x28\x00\x00\x00";' \
    | nc -w 1 -p 500 -u rpe-foo.czech 500

Oh yeah, this finally deserved a response:

383.050874 10.18.144.12 -> 10.18.144.11 ISAKMP Identity Protection (Main Mode)

0000  00 0a e4 2f 61 eb 00 03 ba 4e 3d 38 08 00 45 00   .../a....N=8..E.
0010  00 38 26 a8 40 00 ff 11 20 d1 0a 12 90 0c 0a 12   .8&.@... .......
0020  90 0b 01 f4 01 f4 00 24 34 71 11 22 33 44 55 66   .......$4q."3DUf
0030  77 88 00 00 00 00 00 00 00 00 00 10 02 00 66 66   w.............ff
0040  66 66 28 00 00 00                                 ff(...

383.051672 10.18.144.11 -> 10.18.144.12 ISAKMP Informational

0000  00 03 ba 4e 3d 38 00 0a e4 2f 61 eb 08 00 45 00   ...N=8.../a...E.
0010  00 99 d3 8b 40 00 ff 11 73 8c 0a 12 90 0b 0a 12   ....@...s.......
0020  90 0c 01 f4 01 f4 00 85 ed 05 11 22 33 44 55 66   ..........."3DUf
0030  77 88 85 75 8e 0f fa a5 5d de 0b 10 05 00 69 a5   w..u....].....i.
0040  63 e4 00 00 00 7d 00 00 00 61 00 00 00 01 01 10   c....}...a......
0050  00 1e 11 22 33 44 55 66 77 88 85 75 8e 0f fa a5   ..."3DUfw..u....
0060  5d de 80 0c 00 01 00 06 00 39 55 44 50 20 50 61   ]........9UDP Pa
0070  63 6b 65 74 20 64 6f 65 73 20 6e 6f 74 20 63 6f   cket does not co
0080  6e 74 61 69 6e 20 65 6e 6f 75 67 68 20 64 61 74   ntain enough dat
0090  61 20 66 6f 72 20 49 53 41 4b 4d 50 20 70 61 63   a for ISAKMP pac
00a0  6b 65 74 80 08 00 00                              ket....

Now that we proved to ourselves that we can construct semi-valid packet it's time to try IKEv2. IKEv2 header is defined in RFC 4306, section 3.1:

                           1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                       IKE_SA Initiator's SPI                  !
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                       IKE_SA Responder's SPI                  !
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !  Next Payload ! MjVer ! MnVer ! Exchange Type !     Flags     !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                          Message ID                           !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                            Length                             !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

On a first sight, it looks the same (for backward compatibility). However, some of the values are different. For IKE header, the main differences are in the Exchange Type and Flags:

                       Exchange Type            Value

                       RESERVED                 0-33
                       IKE_SA_INIT              34
                       IKE_AUTH                 35
                       CREATE_CHILD_SA          36
                       INFORMATIONAL            37
                       RESERVED TO IANA         38-239
                       Reserved for private use 240-255

IKE_SA_INIT is our guy ('echo 0t34=x | mdb' produces 0x22).

The flags are now used to indicate the exchange. Set 3rd bit to say we are the Initiator. We will retain the source port even though IKEv2 supports ports other than 500 and 4500 because we're dealing with IKEv1 implementation. Now slightly change our packet code (don't forget to change the Version field to 2.0):

perl -e 'print "\x11\x22\x33\x44\x55\x66\x77\x88\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x22\x08\x66\x66\x66\x66\x28\x00\x00\x00";' \
    | nc -w 1 -p 500 -u rpe-foo.czech 500

And we got a nice response (since the responder runs recent version libike.so):

1013.190867 10.18.144.12 -> 10.18.144.11 ISAKMP IKE_SA_INIT

0000  00 0a e4 2f 61 eb 00 03 ba 4e 3d 38 08 00 45 00   .../a....N=8..E.
0010  00 38 26 aa 40 00 ff 11 20 cf 0a 12 90 0c 0a 12   .8&.@... .......
0020  90 0b 01 f4 01 f4 00 24 34 71 11 22 33 44 55 66   .......$4q."3DUf
0030  77 88 00 00 00 00 00 00 00 00 00 20 22 08 66 66   w.......... ".ff
0040  66 66 28 00 00 00                                 ff(...

1013.192005 10.18.144.11 -> 10.18.144.12 ISAKMP Informational

0000  00 03 ba 4e 3d 38 00 0a e4 2f 61 eb 08 00 45 00   ...N=8.../a...E.
0010  00 83 d3 8d 40 00 ff 11 73 a0 0a 12 90 0b 0a 12   ....@...s.......
0020  90 0c 01 f4 01 f4 00 6f 66 da 11 22 33 44 55 66   .......of.."3DUf
0030  77 88 5c 36 e3 75 a2 7b 8e fe 0b 10 05 00 87 03   w.\6.u.{........
0040  0c f5 00 00 00 67 00 00 00 4b 00 00 00 01 01 10   .....g...K......
0050  00 05 11 22 33 44 55 66 77 88 5c 36 e3 75 a2 7b   ..."3DUfw.\6.u.{
0060  8e fe 80 0c 00 01 00 06 00 23 49 6e 76 61 6c 69   .........#Invali
0070  64 20 49 53 41 4b 4d 50 20 6d 61 6a 6f 72 20 76   d ISAKMP major v
0080  65 72 73 69 6f 6e 20 6e 75 6d 62 65 72 80 08 00   ersion number...
0090  00   

The only thing which is not nice is our terminal since nc(1) dumped the binary packet to it. Let's try again with some post-processing:

# perl -e 'print "\x11\x22\x33\x44\x55\x66\x77\x88\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x22\x08\x66\x66\x66\x66\x28\x00\x00\x00";'     
| nc -w 1 -p 500 -u rpe-foo.czech 500 | od -c
0000000 021   "   3   D   U   f   w 210 237   y 254 264 351 333 007 344
0000020 013 020 005  \0   [ 251 244   j  \0  \0  \0   g  \0  \0  \0   K
0000040  \0  \0  \0 001 001 020  \0 005 021   "   3   D   U   f   w 210
0000060 237   y 254 264 351 333 007 344 200  \f  \0 001  \0 006  \0   #
0000100   I   n   v   a   l   i   d       I   S   A   K   M   P       m
0000120   a   j   o   r       v   e   r   s   i   o   n       n   u   m
0000140   b   e   r 200  \b  \0  \0
0000147

The fix is obviously in place.

Some light intro first: OpenSSL has a concept of plugins/add-ons called 'engines' which can supply alternative implementation of crypto operations (digests, symmetric and asymmetric ciphers and random data generation). The main reason for the existence of the engines is the ability to offload crypto ops to hardware. (Open)Solaris ships with an engine called PKCS#11 engine which provides access to Solaris Cryptographic Framework which in turn can provide access to HW crypto.

I spent some time fixing bugs in OpenSSL PKCS#11 engine in Solaris so I got quite intimate with its internals. Recently while discussing an upcoming feature with Jan he asked me why one particular detail in the engine is done one way and not the other (it's the fork() detection not done via atfork handlers; for the curious). It took me some thinking to find the answer (I focused on the other changes at that time) which made us realize that it would be good to summarize the design choices behind the engine and also to document the internals so that others can quickly see what's going on inside and also be able to do changes in the engine without reverse engineer the thoughts behind it. The outcome is a set of slides which I hope succinctly describe both the overall picture and the gritty details.

The presentation can be downloaded here.

I have spent some time fixing bugs in KSSL (kernel SSL proxy) implementation in Solaris and got familar with it (and the KSSL development team) so with delight I can co-announce that the KSSL project has been opened on opensolaris.org.

To me, KSSL is one of the unique projects in the (Open)Solaris security land in a sense it is tightly integrated into the system and is a consumer of several major subsystems (networking, crypto framework) which makes it interesting for study and also for extending it in creative ways.

We will start adding more content to the pages, including design documentation and description of KSSL internals. Also, this marks major milestone in a way how KSSL team does its job. From now on all non-confidential discussions, reviews etc. will happen in the open. Feel free to join the project and participate if you're interested ! (become an observer and join the mailing list)

I have just integrated couple of changes which I believe are the first contributed externally to the Testing community as an open-source contribution. The changes add couple of new tests to the nc test suite to cover the enhancement described in PSARC/2008/680 (which is present in Nevada since build 106). This is the stuff which allows you to run nc(1) in client mode with complex portlist specifications. Previously it was possible only to use simple port ranges like 22-80, with this change one can connect to e.g. 22,24,50-80,66,1024-2048. Little example how it might be useful:

$ nc -v -z grok.czech 22,25,80-88,8080
Connection to grok.czech 22 port [tcp/ssh] succeeded!
nc: connect to 129.157.71.49 port 25 [host grok.czech] (tcp) failed: Connection refused
Connection to grok.czech 80 port [tcp/*] succeeded!
nc: connect to 129.157.71.49 port 81 [host grok.czech] (tcp) failed: Connection refused
nc: connect to 129.157.71.49 port 82 [host grok.czech] (tcp) failed: Connection refused
nc: connect to 129.157.71.49 port 83 [host grok.czech] (tcp) failed: Connection refused
nc: connect to 129.157.71.49 port 84 [host grok.czech] (tcp) failed: Connection refused
nc: connect to 129.157.71.49 port 85 [host grok.czech] (tcp) failed: Connection refused
nc: connect to 129.157.71.49 port 86 [host grok.czech] (tcp) failed: Connection refused
nc: connect to 129.157.71.49 port 87 [host grok.czech] (tcp) failed: Connection refused
nc: connect to 129.157.71.49 port 88 [host grok.czech] (tcp) failed: Connection refused
Connection to grok.czech 8080 port [tcp/*] succeeded!

Back to the testing part. The putback (yes, stcnv-gate is still using Teamware) log for this change looks like this (I have modified Erik's e-mail a bit):

6786859 portranges_complex_spec is missing the listener
6754842 extended port list specification needs to be tested
Code contributed by Erik Trauschke <erik.trauschke AT freenet.de>

I think this is really nice example of the ideal state - the contributor not only did the feature part but also the testing part. It shows a great degree of responsibility - not just throwing some code "over the fence" but fully participating in the process to ensure the quality even in the long term.

The tests are both positive and negative. Each purpose in portranges directory is numbered and the following numbers match the test purpose numbers:

• 5-12 ensure nc treats ports 0 and 65536 as invalid
  Previously, it was possible to listen on ports 0 and 65536, with Erik's changes this is no longer true so we need to add regression tests for both cases (client/server) and both ports.
• 13-19 see if various malformed port list specifications are considered as invalid
  Each purpose needs not only positive tests which make sure the functionality actually works but also negative tests which ensure it does not misbehave. In this case, invalid port list specifications are thrown at nc(1) to see it reacts accordingly (with error, that is).
• 20-25 test the functionality of complex port lists
  This is the bunch of test which see if the functionality actually works.
• 26 tests reallocation
  Since the internal representation of the port list is now dynamically allocated and there is a default pre-allocated value which is reallocated if needed we need to test the case of reallocation.

To be able to do such integration there is now a Test development process. It's similar to the process used in ON community but it's more lightweight. The main difference is that the request-sponsor part is done informally via the testing-discuss mailing list and there is no list of bugs to pick up from. But don't be shy, whether you're adding new functionality or completely new program, the Testing community is here to help you.

Each build of (Open)Solaris is tested with a variety of test suites on variety of platforms and I wanted nc test suite to participate in these runs.
Eoin Hughes from PIT team (which runs those tests) was kind enough to workaround couple of bugs (which are fixed now) in the test suite so it can be run in PIT environment. Later on, I got a report from Eoin that as a result of nc test suite run CR 6793191 (watchmalloc triggers system panic on sockfs copyin) was caught. This bug is manifested by a panic:

Panic message (this particular panic is on a DomU, although this happens across the board):
panic[cpu0]/thread=ffffff0150ce1540: copyin_noerr: argument not in kernel address space

ffffff000416dcf0 unix:bcopy_ck_size+102 ()
ffffff000416ddb0 genunix:watch_xcopyin+151 ()
ffffff000416dde0 genunix:watch_copyin+1d ()
ffffff000416de50 sockfs:copyin_name+91 ()
ffffff000416deb0 sockfs:bind+90 ()
ffffff000416df00 unix:brand_sys_syscall32+328 ()

The bug is actually a regression caused by CR 6292199 (bcopy and kcopy should'nt use rep, smov) and was fixed by an engineer from Intel in OpenSolaris/Nevada code base.

This is instance of an event which I like so much - unintended positive consequence elsewhere. In contrast with so called collateral damage this is something which is beneficial in other areas. I've written nc test suite to test primarily nc(1) command but here it proved to be useful for testing other areas of the system as well. In this case it was thanks to the fact that the test suite is run with memory leak checking by default (see NC_PRELOADS variable in src/suites/net/nc/include/vars file).

And yes, CR 6793191 is fixed by now.

Since the days when John Beck added command line editing to zonecfg Mark Phalan did similar thing to Kerberos utilities and Huie-Ying Lee to sftp. IPsec utilities (ipseckey(1M) and ikeadm(1M)) offered the ability to enter commands in interactive mode for a long time but only since Nevada build 112, the commands support command line editing and history too. Again, thanks to libtecla (shipped with Solaris/OpenSolaris).

Lessons learned:

• adding full-blown command line editing support is hard.
  Adding the initial support is quite easy. However, more advanced features could require substantial work. This is especially true for tab completion. For sftp Huie-Ying decided to add tab completion in the future phase because of the ambiguities when completing names of files (when to complete local files versus remote files).
  I did the same with tab completion for IPsec utilities - the integration only delivers basic command line editing support, without tab completion. The problem with ipseckey(1M) and ikeadm(1M) is that their grammar is quite bifurcated and has contexts. For example, you cannot use encr_alg with AH SAs in ipseckey. Or, it would be erroneous to tab complete a valid command in the middle of entering a key if the key hex sequence contained sub-string of a valid command. The hardest part is I think offering the right tables of valid commands in given context. E.g. in our case a command line in our case must start with top-level command. Each top-level command offers several valid sub-commands and we do not offer invalid sub-commands for given top-level command so there is a necessity to track the state of the finite state machine describing the grammar contexts.
  Also, after the user entered src we do not want to allow him to enter it again on the same command line. Also, if the user already entered say add esp spi we are expecting SPI number, not a command name.
  Ideally, to solve this problem in nice way there should be a meta library (or additional API in libtecla) which would offer the ability to link command tables and set the contexts.
• interruptible cycles in command line mode
  ipseckey's monitor command reads from a PF_KEY socket in a loop. The loop is normally interruptible by SIGINT. To do so in libtecla environment (we do not want to exit the command line upon SIGINT and yet still need to interrupt the cycle), something like this is needed:

       static void
       monitor_catch(int signal)
       {
       if (!interactive)
               errx(signal, gettext("Bailing on signal %d."), signal);
       }
  
       void
       doreadcycle(void)
       {
       ...
          
       /* Catch ^C. */
       newsig.sa_handler = monitor_catch;
       newsig.sa_flags = 0;
       (void) sigemptyset(&newsig.sa_mask);
       (void) sigaddset(&newsig.sa_mask, SIGINT);
       (void) sigaction(SIGINT, &newsig, &oldsig);
  
       for (; ; ) {
               rc = read(keysock, samsg, sizeof (get_buffer));
               /* handle the data */
       }
  
       /* restore old behavior */
       if (interactive)
               (void) sigaction(SIGINT, &oldsig, NULL);
       }
  

• interaction with SMF
  While it's fine to bail out in interactive mode with error, due to the nature of IPsec commands (they can read the config files using the same routines as for interactive mode and they are used as SMF services to bring up IPsec policy and keys after boot) we need to distinguish the interactive and non-interactive mode.
• maximum command line history value
  It seems that the second parameter to new_GetLine() - histlen is commonly misunderstood. This variable does not express the number of maximum lines in the history but instead maximum size of the history buffer in bytes. If the buffer becomes full, libtecla does not trim the last line but shifts instead.
  Given the first parameter to new_GetLine() expresses maximum command line size (in bytes) one needs to do some calculations and estimates on what will be needed too avoid too big buffer - ipseckey is used to enter key material so the line could become quite long. Say we wanted to keep 1024 lines. If the maximum length of the line is 1024 this will give us 1 megabyte buffer which seems too much for a simple application. Thus I did some guessing and set the buffer size accordingly:
  For "common" ipseckey configuration commands (think moderately bifurcated 'add') it's cca 300 characters. Mostly however, the users enter query commands like 'flush esp', 'dump ah' and the like so this is somewhere around say 30 characters. Say 30% of the commands are configuration and the rest is queries. To hold 100 such commands only cca 10K memory is required. In the end I chose 64K to be able to hold 15 of the biggies (4K) commands.

After multiple rounds of code review the netcat (or nc) test suite is now finally in the onnv-stc2gate. The test suite has its home in the OpenSolaris Networking community (see the networking tests page for the list of networking test suites).
The source code is present in the src/suites/net/nc/ directory and SUNWstc-netcat packages can be downloaded from OpenSolaris Download center.

Before I go further, this is how it looks like when the test suite is run (the output is trimmed a bit):

vk:honeymooners:/opt/SUNWstc-nc$ run_test nc
Validating Arguments...
New TET_ROOT for this run : /var/tmp/honeymooners_27828
The results will be available in /var/tmp/results.27828
tcc: journal file is /var/tmp/results.27828/testlog
12:45:57  Execute /tests/dflag/tc_dflag
12:46:04  Execute /tests/hflag/tc_hflag
12:46:05  Execute /tests/kflag/tc_kflag
12:46:11  Execute /tests/nflag/tc_nflag
12:46:15  Execute /tests/portranges/tc_portranges
12:46:23  Execute /tests/pflag/tc_pflag
12:46:26  Execute /tests/sflag/tc_sflag
12:46:35  Execute /tests/Uflag/tc_Uflag
12:46:36  Execute /tests/vflag/tc_vflag
12:46:43  Execute /tests/zflag/tc_zflag
12:46:46  Execute /tests/iflag/tc_iflag
12:46:59  Execute /tests/lflag/tc_lflag
12:47:29  Execute /tests/rflag/tc_rflag
12:48:16  Execute /tests/Tflag/tc_Tflag
12:48:33  Execute /tests/uflag/tc_uflag
12:48:50  Execute /tests/wflag/tc_wflag
##################################################
TC /tests/dflag/tc_dflag

TP 1 tc_dflag PASS
##################################################
TC /tests/hflag/tc_hflag

TP 1 tc_hflag PASS

...

##################################################
                 SUMMARY      
                 =======      
 
Number of Tests : 50

PASS            : 50
FAIL            : 0
UNRESOLVED      : 0
UNINITIATED     : 0
OTHER           : 0
 
##################################################

Test Logs are at /var/tmp/results.27828, Journal File = /var/tmp/results.27828/testlog 

vk:honeymooners:/opt/SUNWstc-nc$

It's been almost a year since I started developing the test suite last Christmas (see the initial blog entry about nc-tet). Since then, I have lost part of the source code in hard drive crash, had to redo the source tree structure, fix ksh style, fix numerous bugs in test suite code and make the test suite more robust. One might ask whether having test suite for such a simple program like nc(1) was worth the hassle. I have only one answer to that: absolutely. First, it gives a confidence of not breaking (most of; see below) existing things when changing/adding functionality and second it helped me (and I hope the others participating/observing the code review on testing-discuss too) to explore what it takes to write a test suite from scratch (I will not go here into details whether I prefer CTI-TET over STF and vice versa).

The Beautiful code book (which I really recommend for anyone tinkering with any source code) contains a chapter called Beautiful tests by Alberto Savoia. I hope that at least some of the test purposes in nc test suite have some degree of beautifulness of at least one of the ways highlighted by Alberto (1. simplicity/efficiency, 2. help making the software being tested better in terms of quality and testability, 3. breadth/thoroughness).

One of the important questions for a test suite is code coverage level. Obviously, for software adhering to the OpenSolaris interface taxonomy model it is important that the test suite exercises all of the Committed interfaces and execution paths around those interfaces. For nc(1) this means a subset of the command line options and their arguments (see PSARC 2007/389 for the actual list). The key is certainly to test the features which are likely to break with an intrusive code change.

Very crude view of test coverage for nc(1) test suite (counting test purposes gives only very remote idea about real coverage but at least provides visual image) looks like this:

       rflag: +
       Tflag: +++++---
       pflag: +
       iflag: +-
       vflag: ++
       kflag: +
       Uflag: +-
       dflag: +
       uflag: ++-
       sflag: +-
       hflag: +
       nflag: +-
       wflag: +
  portranges: +---
       lflag: ++++++++----------

One plus character stands for one positive test purpose, minus is negative test purpose.

Side note: the above ASCII graph was produced using test-coverage-graph.sh script (which presumes certain naming scheme for test purpose files). Just pipe a file listing into the script with test purpose filenames compliant to the scheme used in ontest-stc2 gate and it will spew out graph similar to the above.

In the above musing about code coverage I left out an important piece - why some of the features are not tested. For nc(1) the yet untested part is the SOCKS protocol support. Basically, this is because test suite environment does not contain SOCKS server to test against. There might not be many people using the -x/-X options but from my own experience nothing is more frustrating than discovering some old dusty corner which had to be fixed long time ago or removed completely. So for now, on my workstation which sits behind SOCKS proxy I have the following in ~/.ssh/config for a server outside corporate network which hosts my personal mailbox so it is accessed every day:

Host bar
  User foo
  Hostname outside.kewl.org
  # NOTE: for nc(1) testing
  ProxyCommand /usr/bin/nc -x socks-proxy.foothere.bar outside.kewl.org %p
  ForwardAgent no
  ForwardX11 no

This ensures (along with upgrades of the workstation to recent Nevada builds periodically) that SOCKS support gets tested as well. And yes, ssh-socks5-proxy-connect(1) and ssh-http-proxy-connect(1) are not really needed.

Now with the test suite in place, anybody modifying nc(1) (there are some RFEs for nc in the oss-bit-size list and other bugfixes or features are also welcome) can have pretty high confidence that his change will not break things. Yes, this means that more nc(1) features are coming.

I will start this one a little bit generically..

Part of standard OpenSolaris/Solaris development process is code review. To facilitate a review, a so-called webrev is needed. A webrev is set of HTML/text/PDF pages and documents which display all the changes between local repository containing the changes and its parent repository. To produce a webrev, simply switch to a repository and run the webrev script (it is part of SUNWonbld package, which can be downloaded from OpenSolaris download center.):

$ cd /local/Source/bugfix-314159.onnv
$ webrev

Assuming /opt/onbld/bin is present in your PATH a webrev will be generated under /local/Source/bugfix-314159.onnv/webrev/ directory.

For OpenSolaris changes, the webrev is usually uploaded to cr.opensolaris.org (every OpenSolaris member has an account automatically created for him) which serves it under http://cr.opensolaris.org/~OSol_username/ (where OSol_username is your OpenSolaris username) and a request for review with a link to the webrev is sent to one of the mailing lists relevant to the change.
Dan Price has written a script which produces RSS feed out of recently uploaded webrevs which is pretty handy substitute for feeds from news/headlines/magazines :)

For a long time I was basically doing the following:

$ cd /local/Source/bugfix-foo.onnv && webrev
$ scp -r webrev cr.opensolaris.org:bugfix-foo.onnv

This had two flaws: first it was slow (because of rcp protocol over SSH channel) and second I had to delete it via separate command (use sftp(1) and rename the old webrev to .trash directory) before uploading new version of the webrev (otherwise couple of permissions errors would follow).

To solve the first problem, rsync (with SSH transport) can be used which makes the upload nearly instantaneous. Second problem can be worked around by using incremental webrevs. Still, this does not seem good enough for code reviews with many iterations.

So, the change made in CR 6752000 introduces the following command line options for automatic webrev upload:

• -U uploads the webrev
• -n suppresses webrev generation
• -t allows to specify custom upload target

webrev.1 man page has been updated to explain the usage. For common OpenSolaris code reviews the usage will probably mostly look like this:

$ webrev -O -U

This will upload the webrev to cr.opensolaris.org under directory named according to local repository name. Further invocations will replace the remote webrev with fresh version.
But it is possible to get more advanced. After the initial webrev is posted, an incremental webrev can be both generated and posted. Assuming you're switched to the repository (via bldenv) and we're dealing with 4th round of code review the following command will perform the task:

webrev_name=`basename $CODEMGR_WS`
webrev -O -U -o $CODEMGR_WS/${webrev_name}.rd4 \
    -p $CODEMGR_WS/${webrev_name}.rd3

The above commands hide maybe not-so-obvious behavior so I'll try to explain it in the table:

+---------------------------+------------------------+-----------------------------------------------------+
| command                   | local webrev directory | remote webrev directory                             |
+---------------------------+------------------------+-----------------------------------------------------+
| webrev -O -U              | $CODEMGR_WS/webrev/    | cr.opensolaris.org/~OSOLuser/`basename $CODEMGR_WS` |
+---------------------------+------------------------+-----------------------------------------------------+
| webrev -O -o \            | $CODEMGR_WS/my_webrev/ | cr.opensolaris.org/~OSOLuser/my_webrev              |
|   $CODEMGR_WS/my_webrev   |                        |                                                     |
+---------------------------+------------------------+-----------------------------------------------------+
| webrev -O \               | $CODEMGR_WS/fix.rd2/   | cr.opensolaris.org/~OSOLuser/fix.rd2                |
|  -p $CODEMGR_WS/fix.rd1 \ |                        |                                                     |
|  -o $CODEMGR_WS/fix.rd2   |                        |                                                     |
+---------------------------+------------------------+-----------------------------------------------------+

Basically, without the -o flag webrev will generate the webrev to local directory named 'webrev' but it will upload it to the directory named after basename of local repository. With the -o flag webrev will use the name of root directory of the repository it is called from for both local and remote storage. This is done to keep the default behavior of generating local webrev to directory named 'webrev'. At the same time, uploading different webrevs to the same remote directory named 'webrev' does not make sense.

NOTE: This behavior is also valid in the case when not enclosed in a repository via ws or bldenv, I have just used $CODEMGR_WS to express root directory of a workspace/repository.

Also, now it is possible to call webrev from within Cadmium Mercurial plugin, so all webrev commands can be prefixed with hg.

NOTE: It will take some time before the changes appear in SUNWonbld packages offered by the download center so it's better to update the sources from the ssh://anon@hg.opensolaris.org/hg/onnv/onnv-gate repository and build and upgrade the SUNWonbld package from there.

As of today, strsep() function lives in Nevada's libc (tracked by CR 4383867 and PSARC 2008/305). This constitutes another step in the quest for more feature-full (in terms of compatibility) libc in OpenSolaris. In binary form, the changes will be available in build 99. The documentation will be part of the string(3C) man page.

Here's a small example of how to use it:

#include <stdio.h>
#include <string.h>
#include <err.h>

int parse(const char *str) {
        char *p = NULL;
        char *inputstring, *origstr;
        int ret = 1;
        
        if (str == NULL)
                errx(1, "NULL string");

        /*
         * We have to remember original pointer because strsep()
         * will change 'inputstr' pointer.
         */
        if ((origstr = inputstring = strdup(str)) == NULL)
                errx(1, "strdup() failed");

        printf("=== parsing '%s'\n", inputstring);
        for ((p = strsep(&inputstring, ",")); p != NULL;
           (p = strsep(&inputstring, ","))) {
                if (p != NULL && *p != '\0')
                        printf("%s\n", p);
                else if (p != NULL) {
                        warnx("syntax error");
                        ret = 0;
                        goto bad;
                }
        }
bad:
        printf("=== finished parsing\n");
        free(origstr);
        return (ret);
}

int main(int argc, char *argv[]) {
        if (argc != 2)
                errx(1, "usage: prog ");

        if (!parse(argv[1]))
                exit(1);

        return (0);
}

This example was actually used as a unit test (use e.g. "1,22,33,44" and "1,22,,44,33" as input string) and it also nicely illustrates important properties of strsep() behavior:

• While searching for tokens, strsep() modifies the original string. This is shared property with strtok().
• Unlike strtok(), strsep() is able to detect empty fields.

There is a function in Solaris' libc which can do token splitting and does not modify the original string - strcspn(). The other notable property of strsep() is that (unlike strtok()) it does not conform to ANSI-C. Time to draw a table:

 function(s)   ISO C90    modifies     detects
                           input     empty fields
-------------+----------+----------+--------------+
 strsep()        No          Yes         Yes
 strtok()        Yes         Yes         No
 strcspn()       Yes         No        Sort of

None of the above functions is bullet-proof. The bottom line is the user should decide which is the most suitable for given task and use it with its properties in mind.

Part of the transition of Mercurial in OpenSolaris are changes in the integration processes. Every RTI has to contain output of hg outgoing -v so the CRT advocates can better see the impact of the changes in terms of changed files. However, the default output is not very readable:

$ hg outgoing -v
comparing with /local/ws-mirrors/onnv-clone.hg
searching for changes
changeset:   7248:225922d15fe6
user:        Vladimir Kotal 
date:        2008-08-06 23:39 +0200

modified:    usr/src/cmd/ldap/ns_ldap/ldapaddent.c usr/src/cmd/sendmail/db/config.h usr/src/cmd/ssh/include/config.h usr/src
/cmd/ssh/include/openbsd-compat.h usr/src/cmd/ssh/include/strsep.h usr/src/cmd/ssh/libopenbsd-compat/Makefile.com usr/src
/cmd/ssh/libopenbsd-compat/common/llib-lopenbsd-compat usr/src/cmd/ssh/libopenbsd-compat/common/strsep.c usr/src/cmd/ssh/libssh
/common/llib-lssh usr/src/common/util/string.c usr/src/head/string.h usr/src/lib/libc/amd64/Makefile usr/src/lib/libc
/i386/Makefile.com usr/src/lib/libc/port/gen/strsep.c usr/src/lib/libc/port/llib-lc usr/src/lib/libc/port/mapfile-vers usr/src
/lib/libc/sparc/Makefile usr/src/lib/libc/sparcv9/Makefile usr/src/lib/passwdutil/Makefile.com usr/src/lib/passwdutil
/bsd-strsep.c usr/src/lib/passwdutil/passwdutil.h usr/src/lib/smbsrv/libsmb/common/mapfile-vers usr/src/lib/smbsrv/libsmb
/common/smb_util.c
added:       usr/src/lib/libc/port/gen/strsep.c
deleted:     usr/src/cmd/ssh/include/strsep.h usr/src/cmd/ssh/libopenbsd-compat/common/strsep.c usr/src/lib/passwdutil/bsd-strsep.c
log:PSARC 2008/305 strsep() in libc
4383867 need strsep() in libc
--------------------------------------------------------------------

In the above case, the list of modified files spans single line which makes the web form used for RTI go really wild in terms of width (I had to wrap the lines manually in the above example otherwise this page would suffer from the same problem). The following steps can be used to make the output a bit nicer:

1. create ~/bin/Mercurial/outproc.py with the following contents:

   from mercurial import templatefilters
   
   def newlines(text):
       return text.replace(' ', '\n')
   
   def outgoing_hook(ui, repo, **kwargs):
       templatefilters.filters["newlines"] = newlines
   

2. hook into outgoing command in ~/.hgrc by adding the following lines into [hooks], [extensions] sections so it looks like this:

   [extensions]
   outproc=~/bin/Mercurial/outproc.py
   
   [hooks]
   pre-outgoing=python:outproc.outgoing_hook
   

3. create ~/bin/Mercurial/style.outgoing with the following contents:

   changeset = outgoing.template
   

4. create ~/bin/Mercurial/outgoing.template with the following contents (the file can be downloaded here):

   changeset:	{rev}:{node|short}
   user:		{author}
   date:		{date|isodate}
   
   modified:
   {files|stringify|newlines}
   
   added:
   {file_adds|stringify|newlines}
   
   deleted:
   {file_dels|stringify|newlines}
   
   log:
   {desc}
   ------------------------------------------------------------------------
   

5. add the following into your ~/.bashrc (or to .rc file of the shell of your choice):

   alias outgoing='hg outgoing --style ~/bin/Mercurial/style.outgoing'
   

After that it works like this:

$ outgoing
comparing with /local/ws-mirrors/onnv-clone.hg
searching for changes
changeset:	7248:225922d15fe6
user:		Vladimir Kotal 
date:		2008-08-06 23:39 +0200

modified:
usr/src/cmd/ldap/ns_ldap/ldapaddent.c
usr/src/cmd/sendmail/db/config.h
usr/src/cmd/ssh/include/config.h
usr/src/cmd/ssh/include/openbsd-compat.h
usr/src/cmd/ssh/include/strsep.h
usr/src/cmd/ssh/libopenbsd-compat/Makefile.com
usr/src/cmd/ssh/libopenbsd-compat/common/llib-lopenbsd-compat
usr/src/cmd/ssh/libopenbsd-compat/common/strsep.c
usr/src/cmd/ssh/libssh/common/llib-lssh
usr/src/common/util/string.c
usr/src/head/string.h
usr/src/lib/libc/amd64/Makefile
usr/src/lib/libc/i386/Makefile.com
usr/src/lib/libc/port/gen/strsep.c
usr/src/lib/libc/port/llib-lc
usr/src/lib/libc/port/mapfile-vers
usr/src/lib/libc/sparc/Makefile
usr/src/lib/libc/sparcv9/Makefile
usr/src/lib/passwdutil/Makefile.com
usr/src/lib/passwdutil/bsd-strsep.c
usr/src/lib/passwdutil/passwdutil.h
usr/src/lib/smbsrv/libsmb/common/mapfile-vers
usr/src/lib/smbsrv/libsmb/common/smb_util.c

added:
usr/src/lib/libc/port/gen/strsep.c

deleted:
usr/src/cmd/ssh/include/strsep.h
usr/src/cmd/ssh/libopenbsd-compat/common/strsep.c
usr/src/lib/passwdutil/bsd-strsep.c

log:
PSARC 2008/305 strsep() in libc
4383867 need strsep() in libc
------------------------------------------------------------------------

I asked Richard Lowe (who has been very helpful with helping getting the transition process done) if next Mercurial version can have newlines function already included and if there could be outgoingtemplate which would be similar to logtemplate in hgrc(5).
In the meantime I will be using the above for my RTIs.

In OpenSolaris world we very much care about correctness and hate regressions (of any kind). If I loosely paraphrase Bryan Cantrill the degree of devotion should be obvious:

This implies that ordinary bug fix should have a unit test accompanying it. But, unit tests are cumbersome when performed by hand and do not mean much if they are not accumulated over time.

For integration of Netcat into OpenSolaris I have developed number of unit tests (basically at least one for each command line option) and couple more after spotting some bugs in nc(1). This means that nc(1) is ripe for having a test suite so the tests can be performed automatically. This is tracked by RFE 6646967. The test suite will live in onnv-stc2 gate which is hosted and maintained by OpenSolaris Testing community.

To create a test suite one can choose between two frameworks: STF and CTI-TET. I have chosen the latter because I wanted to try something new and also because CTI-TET seems to be the recommended framework these days.

The work on nc test suite has started during Christmas break 2007 and after recovery from lost data it is now in pretty stable state and ready for code review. This is actually somewhat exciting because nc test suite is supposed to be the first OpenSolaris test suite developed in the open.

Fresh webrev is always stored on cr.opensolaris.org in nc-tet.onnv-stc2 directory. Everybody is invited to participate in the code review.

Code review should be performed via testing-discuss at opensolaris.org mailing list (subscribe via Testing / Discussions). It has web interface in the form of testing-discuss forum.

So, if you're familiar with ksh scripting or CTI-TET framework (both not necessary) you have unique chance to bash (not bash) my code ! Watch for official code review announcement on the mailing list in the next couple of days.

Lastly, another philosophical food for thought: Test suites are sets of programs and scripts which serve mainly one purpose - they should prevent bugs from happening in the software they test. But, test suites are software too. Presence of bugs in test suites is an annoying phenomenon. How to get rid of that one ?

During nc(1) preintegration testing, short time before it went back I had found that 'cat /etc/passwd | nc localhost 4444' produced endless loop with 100% CPU utilization, looping in calls doing poll(2) (I still remember my laptop suddenly getting much warmer than it should be and CPU fan cranking up). 'nc localhost 4444 < /etc/password' was not exhibiting that behavior.
The cause was a difference between poll(2) implementation on BSD and Solaris. Since I am working on Netcat in Solaris again (adding more features, stay tuned), it's time to take a look back and maybe even help people porting similar software from BSD to Solaris.

The issue appears because POLLHUP is set in read events bitfield for stdin after pipe is closed (or to be more precise - after the producer/write end is done) on Solaris. poll.c (which resembles readwrite() function from nc) illustrates the issue:

01 #include <stdio.h>
02 #include <poll.h>
03 
04 #define LEN  1024
05 
06 int main(void) {
07      int timeout = -1;
08      int n;
09      char buf[LEN];
10      int plen = LEN;
11 
12      struct pollfd pfd;
13 
14      pfd.fd = fileno(stdin);
15      pfd.events = POLLIN;
16 
17      while (pfd.fd != -1) {
18              if ((n = poll(&pfd, 1, timeout)) < 0) {
19                      err(1, "Polling Error");
20              }
21              fprintf(stderr, "revents = 0x%x [ %s %s ]\n",
22                  pfd.revents,
23                  pfd.revents & POLLIN ? "POLLIN" : "",
24                  pfd.revents & POLLHUP ? "POLLHUP" : "");
25      
26              if (pfd.revents & (POLLIN|POLLHUP)) {
27                      if ((n = read(fileno(stdin), buf, plen)) < 0) {
28                              fprintf(stderr,
29                                  "read() returned neg. val (%d)\n", n);
30                              return;
31                      } else if (n == 0) {
32                              fprintf(stderr, "read() returned 0\n", n);
33                              pfd.fd = -1;
34                              pfd.events = 0;
35                      } else {
36                              fprintf(stderr, "read: %d bytes\n", n);
37                      }
38              }
39      }
40 }

Running it on NetBSD (chosen because my personal non-work mailbox is hosted on a machine running it) produces the following:

otaku[~]% ( od -N 512 -X -v /dev/zero | sed 's/ [ \t]*/ /g'; sleep 3 ) | ./poll
revents = 0x1 [ POLLIN  ]
read: 1024 bytes
revents = 0x1 [ POLLIN  ]
read: 392 bytes
revents = 0x11 [ POLLIN POLLHUP ]
read() returned 0

I had to post-process the output of od(1) (because of difference between output of od(1) on NetBSD and Solaris) and slow the execution down a bit (via sleep) in order to make things more visible (try to run the command without the sleep and the pipe will be closed too quickly). On OpenSolaris the same program produces different pattern:

moose:~$ ( od -N 512 -X -v /dev/zero | sed 's/ [ \t]*/ /g' ; sleep 3 ) | ./poll 
revents = 0x1 [ POLLIN  ]
read: 1024 bytes
revents = 0x1 [ POLLIN  ]
read: 392 bytes
revents = 0x10 [  POLLHUP ]
read() returned 0

So, the program is now obviously correct. Had the statement on line 26 checked only POLLIN, the command above (with or without the sleep) would go into endless loop on Solaris:

revents = 0x11 [ POLLIN POLLHUP ]
read: 1024 bytes
revents = 0x11 [ POLLIN POLLHUP ]
read: 392 bytes
revents = 0x10 [  POLLHUP ]
revents = 0x10 [  POLLHUP ]
revents = 0x10 [  POLLHUP ]
...

Both OSes set POLLHUP after the pipe is closed. The difference is that while BSD always indicates POLLIN (even if there is nothing to read), Solaris strips it after data stream ended. So, which one is correct ? poll() function as described by OpenGroup says that "POLLHUP and POLLIN are not mutually exclusive". This means both implementations seem to conform to the IEEE Std 1003.1, 2004 Edition standard (part of POSIX) in this respect.

However, the POSIX standard also says:

In each pollfd structure, poll ( ) shall clear the revents member, except that where the application requested a report on a condition by setting one of the bits of events listed above, poll ( ) shall set the corresponding bit in revents if the requested condition is true. In addition, poll ( ) shall set the POLLHUP, POLLERR, and POLLNVAL flag in revents if the condition is true, even if the application did not set the corresponding bit in events.

This might be still ok even though POLLIN flag remains to be set in NetBSD's poll() even after no data are available for reading (try to comment out lines 33,34 and run as above) because the standard says about POLLIN flag: For STREAMS, this flag is set in revents even if the message is of zero length.

Without further reading it is hard to tell how exactly should POSIX compliant poll() look like. On the Austin group mailing list there was a thread about poll() behavior w.r.t. POLLHUP suggesting this is fuzzy area.

Anyway, to see where exactly is POLLHUP set for pipes in OpenSolaris go to fifo_poll(). The function _sets_ the revents bit field to POLLHUP so the POLLIN flag is wiped off after that. fifo_poll() is part of fifofs kernel module which has been around in Solaris since late eighties (I was still in elementary school the year fifovnops.c appeared in SunOS code base :)). NetBSD has fifofs too but the POLLHUP flag gets set via bit logic operation in pipe_poll() which is part of syscall processing code. The difference between OpenSolaris and NetBSD (whoa, NetBSD project uses OpenGrok !) POLLHUP attitude (respectively) is now clear:

The flashback is still alive even weeks after: the day before my presentation at FIRST Technical Colloquium in Prague I brought my 2 years old laptop with the work-in-progress slides to the office. Since I wanted to finish the slides in the evening a live-upgrade process was fired off on the laptop to get fresh Nevada version. (of course, to show off during the presentation ;))
LU is very I/O intensive process and the red Ferrari notebooks tend to get _very_ hot. In the afternoon I noticed that the process failed. To my astonishment, the I/O operations started to fail. After couple of reboots (and zpool status / fmadm faulty commands) it was obvious that the disk cannot be trusted anymore. I was able to rescue some data from the ZFS pool which was spanning the biggest slice of the internal disk but not all data. (ZFS is not willing to get corrupted data out.) My slides were lost as well as other data.

After some time I stumbled upon James Gosling's blog entry about ZFS mirroring on laptop. This get me started (or more precisely I was astonished and wondered how is it possible that this idea escaped me because at that time ZFS had been in Nevada for a long time) and I have discovered several similar and more in-depth blog entries about the topic.
After some experiments with borrowed USB disk it was time to make it reality on a new laptop.

The process was a multi-step one:

1. First I had to extend the free slice #7 on the internal disk so it spans the remaining space on the disk because it was trimmed after the experiments. In the end the slices look like this in format(1) output:

   Part      Tag    Flag     Cylinders         Size            Blocks
     0       root    wm       3 -  1277        9.77GB    (1275/0/0)   20482875
     1 unassigned    wm    1278 -  2552        9.77GB    (1275/0/0)   20482875
     2     backup    wm       0 - 19442      148.94GB    (19443/0/0) 312351795
     3       swap    wu    2553 -  3124        4.38GB    (572/0/0)     9189180
     4 unassigned    wu       0                0         (0/0/0)             0
     5 unassigned    wu       0                0         (0/0/0)             0
     6 unassigned    wu       0                0         (0/0/0)             0
     7       home    wm    3125 - 19442      125.00GB    (16318/0/0) 262148670
     8       boot    wu       0 -     0        7.84MB    (1/0/0)         16065
     9 alternates    wu       1 -     2       15.69MB    (2/0/0)         32130
   

2. Then the USB drive was connected to the system and recognized via format(1):

   AVAILABLE DISK SELECTIONS:
          0. c0d0 
             /pci@0,0/pci-ide@12/ide@0/cmdk@0,0
          1. c5t0d0 
             /pci@0,0/pci1025,10a@13,2/storage@4/disk@0,0
   

3. Live upgrade boot environment which was not active was deleted via ludelete(1M) and the slice was commented out in /etc/vfstab. This was needed to make zpool(1M) happy.
4. ZFS pool was created out of the slice on the internal disk (c0d0s7) and external USB disk (c5t0d0). I had to force it cause zpool(1M) complained about the overlap of c0d0s2 (slice spanning the whole disk) and c0d0s7:

   # zpool create -f data mirror c0d0s7 c5t0d0
   

   For a while I have struggled with finding a name for the pool (everybody seems either to stick to the 'tank' name or come up with some double-cool-stylish name which I wanted to avoid because of the likely degradation of the excitement from that name) but then chosen the ordinary data (it's what it is, after all).
5. I have verified that it is possible to disconnect the USB disk and safely connect it while an I/O operation is in progress:

   root:moose:/data# mkfile 10g /data/test &
   [1] 10933
   root:moose:/data# zpool status
     pool: data
    state: ONLINE
    scrub: none requested
   config:
   
   	NAME        STATE     READ WRITE CKSUM
   	data        ONLINE       0     0     0
   	  mirror    ONLINE       0     0     0
   	    c0d0s7  ONLINE       0     0     0
   	    c5t0d0  ONLINE       0     0     0
   
   errors: No known data errors
   

   It survived it without a hitch (okay, I had to wait for the zpool command to complete a little bit longer due to the still ongoing I/O but that was it) and resynced the contents automatically after the USB disk was reconnected:

   root:moose:/data# zpool status
     pool: data
    state: DEGRADED
   status: One or more devices are faulted in response to persistent errors.
   	Sufficient replicas exist for the pool to continue functioning in a
   	degraded state.
   action: Replace the faulted device, or use 'zpool clear' to mark the device
   	repaired.
    scrub: resilver in progress for 0h0m, 3.22% done, 0h5m to go
   config:
   
   	NAME        STATE     READ WRITE CKSUM
   	data        DEGRADED     0     0     0
   	  mirror    DEGRADED     0     0     0
   	    c0d0s7  ONLINE       0     0     0
   	    c5t0d0  FAULTED      0     0     0  too many errors
   
   errors: No known data errors
   

   Also, with heavy I/O it is needed to mark the zpool as clear after the resilver completes via zpool clear data because the USB drive is marked as faulty. Normally this will not happen (unless the drive really failed) because I will be connecting and disconnecting the drive only when powering on or shutting down the laptop, respectively.
6. After that I have used Mark Shellenbaum's blog entry about ZFS delegated administration (it was Mark who did the integration) and ZFS Delegated Administration chapter from OpenSolaris ZFS Administration Guide and created permissions set for my local user and assigned those permissions to the ZFS pool 'data' and the user:

     # chmod A+user:vk:add_subdirectory:fd:allow /data
     # zfs allow -s @major_perms clone,create,destroy,mount,snapshot data
     # zfs allow -s @major_perms send,receive,share,rename,rollback,promote data
     # zfs allow -s @major_props copies,compression,quota,reservation data
     # zfs allow -s @major_props snapdir,sharenfs data
     # zfs allow vk @major_perms,@major_props data
   

   All of the commands had to be done under root.
7. Now the user is able to create a home directory for himself:

     $ zfs create data/vk
   

8. Time to setup the environment of data sets and prepare it for data. I have separated the data sets according to a 'service level'. Some data are very important (e.g. presentations ;)) to me so I want them multiplied via the ditto blocks mechanism so they are actually present 4 times in case of copies dataset property set to 2. Also, documents are not usually accompanied by executable code so the exec property was set to off which will prevent running scripts or programs from that dataset.
   Some data are volatile and in high quantity so they do not need any additional protection and it is good idea to compress them with better compression algorithm to save some space. The following table summarizes the setup:

      dataset             properties                       comment
    +-------------------+--------------------------------+------------------------+
    | data/vk/Documents | copies=2                       | presentations          |
    | data/vk/Saved     | compression=on exec=off        | stuff from web         |
    | data/vk/DVDs      | compression=gzip-8 exec=off    | Nevada ISOs for LU     |
    | data/vk/CRs       | compression=on copies=2        | precious source code ! |
    +-------------------+--------------------------------+------------------------+
   

   So the commands will be:

     $ zfs create -o copies=2 data/vk/Documents
     $ zfs create -o compression=gzip-3 -o exec=off data/vk/Saved
     ...
   

9. Now it is possible to migrate all the data, change home directory of the user to /data/vk (e.g. via /usr/ucb/vipw) and relogin.

However, this is not the end of it but just beginning. There are many things to make the setup even better, to name a few:

• setup some sort of automatic snapshots for selected datasets
  The set of scripts and SMF service for doing ZFS snapshots and backup (see ZFS Automatic For The People and related blog entries) made by Tim Foster could be used for this task.
• make zpool scrub run periodically
  
• detect failures of the disks
  This would be ideal to see in Gnome panel or Gnome system monitor.
• setup off-site backup via SunSSH + zfs send
  This could be done using the hooks provided by Tim's scripts (see above).
• Set quotas and reservations for some of the datasets.
• Install ZFS scripts for Gnome nautilus so I will be able to browse, perform and destroy snapshots in nautilus. Now which set of scripts to use ? Chris Gerhard's or Tim Foster's ? Or should I just wait for the official ZFS support for nautilus to be integrated ?
• Find how exactly will the recovery scenario (in case of laptop drive failure) will look like.
  To import the ZFS pool from the USB disk should suffice but during my experiments I was not able to complete it successfully.

With all the above the data should be safe from disk failure (after all disks are often called "spinning rust" so they are going to fail sooner or later) and also the event of loss of both laptop and USB disk.

Lastly, a philosophical thought: One of my colleagues considers hardware as a necessary (and very faulty) layer which is only needed to make it possible to express the ideas in software. This might seem extreme but come to think of it. ZFS is special in this sense - being a software which provides that bridge, it's core idea to isolate the hardware faults.

Two weeks ago (yeah, I am a slacker) FIRST technical colloquium was held in Prague and we (me and Sasha) were given the opportunity to attend (the fact the Derrick serves as FIRST chair in the steering comittee has of course something to do with it).

I only attended one day of the technical colloquium (Tuesday 29th). The day was filled with various talks and presentations. Most of them were performed by various CERT teams members from around the world. This was because this event was a joint meeting of FIRST and TF-CSIRT. It was definitely interesting to see very different approaches to the shared problem set (dealing with incidents, setting up honey pots, building forensic analysis labs, etc.). Not only these differences stemmed from sizes of the networks and organizations but also (and that was kind of funny) from nationalities.
In the morning I talked about the integration of Netcat into Solaris, describing the process, current features and planned enhancements and extensions.

The most anticipated talk was by Adam Laurie who is entertaining guy involved in many hacker-like activities (see e.g. A hacker games the hotel article by Wired) directed at proving insecurities in many publicly used systems.
Adam (brother of Ben Laurie, author of Apache-SSL and OpenSSL contributor) first started with intro about satellite scanning, insecure hotel safes (with backdoors installed by the manufacturers which can be overcome by a screwdriver). Then he proceeded to talk about RFID chips, mainly about cloning.

Also, at the "social event" in the evening I had the pleasure to share a table with Ken van Wyk who is overall cool fellow and the author of Secure coding and Incident response books from O'Reilly.

In overall, it was interesting to see so many security types in a room and get to know some of them.