*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->OpenBSD man pages -> pstruct (1)              



NAME    [Toc]    [Back]

       c2ph, pstruct - Dump C structures as generated from "cc -g
       -S" stabs

SYNOPSIS    [Toc]    [Back]

           c2ph [-dpnP] [var=val] [files ...]

       OPTIONS    [Toc]    [Back]


           -w   wide;  short  for:  type_width=45 member_width=35
           -x   hex;  short  for:   offset_fmt=x  offset_width=08
size_fmt=x size_width=04

           -n   do  not generate perl code  (default when invoked
as pstruct)
           -p  generate perl code         (default  when  invoked
as c2ph)
           -v  generate perl code, with C decls as comments

           -i  do NOT recompute sizes for intrinsic datatypes
           -a  dump information on intrinsics also

           -t  trace execution
           -d  spew reams of debugging output

           -slist  give comma-separated list a structures to dump

DESCRIPTION    [Toc]    [Back]

       The following is the old c2ph.doc documentation by Tom
       Christiansen <tchrist@perl.com> Date: 25 Jul 91 08:10:21

       Once upon a time, I wrote a program called pstruct.  It
       was a perl program that tried to parse out C structures
       and display their member offsets for you.  This was especially
 useful for people looking at binary dumps or poking
       around the kernel.

       Pstruct was not a pretty program.  Neither was it particularly
 robust.  The problem, you see, was that the C compiler
 was much better at parsing C than I could ever hope
       to be.

       So I got smart:  I decided to be lazy and let the C compiler
 parse the C, which would spit out debugger stabs for
       me to read.  These were much easier to parse.  It's still
       not a pretty program, but at least it's more robust.

       Pstruct takes any .c or .h files, or preferably .s ones,
       since that's the format it is going to massage them into
       anyway, and spits out listings like this:
        struct tty {
          int                                        tty.t_locker
000      4
          int                                   tty.t_mutex_index
004      4
          struct      tty     *                     tty.t_tp_virt
008      4
          struct         clist                         tty.t_rawq
00c     20
            int                                   tty.t_rawq.c_cc
00c      4
            int                                 tty.t_rawq.c_cmax
010      4
            int                                  tty.t_rawq.c_cfx
014      4
            int                                  tty.t_rawq.c_clx
018      4
            struct    tty   *                 tty.t_rawq.c_tp_cpu
01c      4
            struct   tty   *                  tty.t_rawq.c_tp_iop
020      4
            unsigned   char   *              tty.t_rawq.c_buf_cpu
024      4
            unsigned   char   *              tty.t_rawq.c_buf_iop
028      4
          struct         clist                         tty.t_canq
02c     20
            int                                   tty.t_canq.c_cc
02c      4
            int                                 tty.t_canq.c_cmax
030      4
            int                                  tty.t_canq.c_cfx
034      4
            int                                  tty.t_canq.c_clx
038      4
            struct   tty   *                  tty.t_canq.c_tp_cpu
03c      4
            struct    tty   *                 tty.t_canq.c_tp_iop
040      4
            unsigned   char   *              tty.t_canq.c_buf_cpu
044      4
            unsigned   char   *              tty.t_canq.c_buf_iop
048      4
          struct         clist                         tty.t_outq
04c     20
            int                                   tty.t_outq.c_cc
04c      4
            int                                 tty.t_outq.c_cmax
050      4
            int                                  tty.t_outq.c_cfx
054      4
            int                                  tty.t_outq.c_clx
058      4
            struct    tty   *                 tty.t_outq.c_tp_cpu
05c      4
            struct   tty   *                  tty.t_outq.c_tp_iop
060      4
            unsigned   char   *              tty.t_outq.c_buf_cpu
064      4
            unsigned   char   *              tty.t_outq.c_buf_iop
068      4
          (*int)()                                tty.t_oproc_cpu
06c      4
          (*int)()                                tty.t_oproc_iop
070      4
          (*int)()                             tty.t_stopproc_cpu
074      4
          (*int)()                             tty.t_stopproc_iop
078      4
          struct       thread      *                   tty.t_rsel
07c      4


       Actually, this was generated by a particular set of
       options.  You can control the formatting of each column,
       whether you prefer wide or fat, hex or decimal, leading
       zeroes or whatever.

       All you need to be able to use this is a C compiler than
       generates BSD/GCC-style stabs.  The -g option on native
       BSD compilers and GCC should get this for you.

       To learn more, just type a bogus option, like -       long
usage message will be provided.  There are a fair
       number of possibilities.

       If you're only a C programmer, than this is the end of the
       message for you.  You can quit right now, and if you care
       to, save off the source and run it when you feel like  it.
       Or not.

       But if you're a perl programmer, then for you I have something
 much more wondrous than just a structure offset

       You see, if you call pstruct by its other incybernation,
       c2ph, you have a code generator that translates C code
       into perl code!  Well, structure and union declarations at
       least, but that's quite a bit.

       Prior to this point, anyone programming in perl who wanted
       to interact with C programs, like the kernel, was forced
       to guess the layouts of the C structures, and then hardwire
 these into his program.  Of course, when you took
       your wonderfully crafted program to a system where the
       sgtty structure was laid out differently, your program
       broke.  Which is a shame.

       We've had Larry's h2ph translator, which helped, but that
       only works on cpp symbols, not real C, which was also very
       much needed.  What I offer you is a symbolic way of getting
 at all the C structures.  I've couched them in terms
       of packages and functions.  Consider the following program:


           require 'syscall.ph';
           require 'sys/time.ph';
           require 'sys/resource.ph';

           $ru = " " x &rusage'sizeof();

           syscall(&SYS_getrusage, &RUSAGE_SELF, $ru)      && die
"getrusage: $!";

           @ru = unpack($t = &rusage'typedef(), $ru);

           $utime =  $ru[ &rusage'ru_utime + &timeval'tv_sec  ]
                  + ($ru[ &rusage'ru_utime + &timeval'tv_usec  ])
/ 1e6;

           $stime =  $ru[ &rusage'ru_stime + &timeval'tv_sec  ]
                  +  ($ru[ &rusage'ru_stime + &timeval'tv_usec ])
/ 1e6;

           printf "you have used %8.3fs+%8.3fu seconds.0, $utime,

       As you see, the name of the package is the name of the
       structure.  Regular fields are just their own names.  Plus
       the following accessor functions are provided for your
           struct      This takes no arguments, and is merely the
number of first-level
                       elements  in the structure.  You would use
this for indexing
                       into arrays of  structures,  perhaps  like

                           $usec = $u[ &user'u_utimer
                                       +    (&ITIMER_VIRTUAL    *
                                       + &itimerval'it_value
                                       + &timeval'tv_usec

           sizeof      Returns the bytes in the structure, or the
member if
                       you pass it an argument, such as


           typedef      This  is  the  perl format definition for
passing to pack and
                       unpack.  If you ask for the typedef  of  a
nothing, you get
                       the  whole  structure,  otherwise  you get
that of the member
                       you ask for.  Padding is taken care of, as
is the magic to
                       guarantee  that  a  union is unpacked into
all its aliases.
                       Bitfields are not quite yet supported however.

           offsetof     This function is the byte offset into the
array of that
                       member.  You may wish to use this for  indexing directly
                       into  the  packed  structure with vec() if
you're too lazy
                       to unpack it.

           typeof      Not to be confused with the typedef accessor function, this
                       one  returns  the  C  type  of that field.
This would allow
                       you to print out a nice structured  pretty
print of some
                       structure  without  knoning anything about
it beforehand.
                       No args to this one is  a  noop.   Someday
I'll post such
                       a  thing  to dump out your u structure for

       The way I see this being used is like basically this:

               %       h2ph        <some_include_file.h         >
               %        c2ph        some_include_file.h        >>
               % install

       It's a little tricker with c2ph because you have to get
       the includes right.  I can't know this for your system,
       but it's not usually too terribly difficult.

       The code isn't pretty as I mentioned  -- I never thought
       it would be a 1000- line program when I started, or I
       might not have begun. :-)  But I would have been less cavalier
 in how the parts of the program communicated with
       each other, etc.  It might also have helped if I didn't
       have to divine the makeup of the stabs on the fly, and
       then account for micro differences between my compiler and

       Anyway, here it is.  Should run on perl v4 or greater.
       Maybe less.


perl v5.8.5                 2002-11-06                          5
[ Back ]
 Similar pages
Name OS Title
c2ph Linux Dump C structures as generated from "cc -g -S" stabs
c2ph IRIX Dump C structures as generated from cc -g -S stabs
pstruct IRIX Dump C structures as generated from cc -g -S stabs
pstruct Linux Dump C structures as generated from "cc -g -S" stabs
alGetEventSrcResource IRIX Return audio resource that generated event
getmonitor IRIX returns the video output format currently being generated by the graphics system
clatzm IRIX applie a Householder matrix generated by CTZRQF to a matrix
dlatzm IRIX applie a Householder matrix generated by DTZRQF to a matrix
slatzm IRIX applie a Householder matrix generated by STZRQF to a matrix
zlatzm IRIX applie a Householder matrix generated by ZTZRQF to a matrix
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service