opcode.pm

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

=cut

# the =cut above is used by _init_optags() to get here quickly

=head1 Predefined Opcode Tags

=over 5

=item :base_core

    null stub scalar pushmark wantarray const defined undef

    rv2sv sassign

    rv2av aassign aelem aelemfast aslice av2arylen

    rv2hv helem hslice each values keys exists delete

    preinc i_preinc predec i_predec postinc i_postinc postdec i_postdec
    int hex oct abs pow multiply i_multiply divide i_divide
    modulo i_modulo add i_add subtract i_subtract

    left_shift right_shift bit_and bit_xor bit_or negate i_negate
    not complement

    lt i_lt gt i_gt le i_le ge i_ge eq i_eq ne i_ne ncmp i_ncmp
    slt sgt sle sge seq sne scmp

    substr vec stringify study pos length index rindex ord chr

    ucfirst lcfirst uc lc quotemeta trans chop schop chomp schomp

    match split qr

    list lslice splice push pop shift unshift reverse

    cond_expr flip flop andassign orassign dorassign and or dor xor

    warn die lineseq nextstate scope enter leave setstate

    rv2cv anoncode prototype

    entersub leavesub leavesublv return method method_named -- XXX loops via recursion?

    leaveeval -- needed for Safe to operate, is safe without entereval

=item :base_mem

These memory related ops are not included in :base_core because they
can easily be used to implement a resource attack (e.g., consume all
available memory).

    concat repeat join range

    anonlist anonhash

Note that despite the existence of this optag a memory resource attack
may still be possible using only :base_core ops.

Disabling these ops is a I<very> heavy handed way to attempt to prevent
a memory resource attack. It's probable that a specific memory limit
mechanism will be added to perl in the near future.

=item :base_loop

These loop ops are not included in :base_core because they can easily be
used to implement a resource attack (e.g., consume all available CPU time).

    grepstart grepwhile
    mapstart mapwhile
    enteriter iter
    enterloop leaveloop unstack
    last next redo
    goto

=item :base_io

These ops enable I<filehandle> (rather than filename) based input and
output. These are safe on the assumption that only pre-existing
filehandles are available for use.  Usually, to create new filehandles
other ops such as open would need to be enabled, if you don't take into
account the magical open of ARGV.

    readline rcatline getc read

    formline enterwrite leavewrite

    print say sysread syswrite send recv

    eof tell seek sysseek

    readdir telldir seekdir rewinddir

=item :base_orig

These are a hotchpotch of opcodes still waiting to be considered

    gvsv gv gelem

    padsv padav padhv padany

    once

    rv2gv refgen srefgen ref

    bless -- could be used to change ownership of objects (reblessing)

    pushre regcmaybe regcreset regcomp subst substcont

    sprintf prtf -- can core dump

    crypt

    tie untie

    dbmopen dbmclose
    sselect select
    pipe_op sockpair

    getppid getpgrp setpgrp getpriority setpriority localtime gmtime

    entertry leavetry -- can be used to 'hide' fatal errors

    entergiven leavegiven
    enterwhen leavewhen
    break continue
    smartmatch

    custom -- where should this go

=item :base_math

These ops are not included in :base_core because of the risk of them being
used to generate floating point exceptions (which would have to be caught
using a $SIG{FPE} handler).

    atan2 sin cos exp log sqrt

These ops are not included in :base_core because they have an effect
beyond the scope of the compartment.

    rand srand

=item :base_thread

These ops are related to multi-threading.

    lock

=item :default

A handy tag name for a I<reasonable> default set of ops.  (The current ops
allowed are unstable while development continues. It will change.)

    :base_core :base_mem :base_loop :base_orig :base_thread

This list used to contain :base_io prior to Opcode 1.07.

If safety matters to you (and why else would you be using the Opcode module?)
then you should not rely on the definition of this, or indeed any other, optag!

=item :filesys_read

    stat lstat readlink

    ftatime ftblk ftchr ftctime ftdir fteexec fteowned fteread
    ftewrite ftfile ftis ftlink ftmtime ftpipe ftrexec ftrowned
    ftrread ftsgid ftsize ftsock ftsuid fttty ftzero ftrwrite ftsvtx

    fttext ftbinary

    fileno

=item :sys_db

    ghbyname ghbyaddr ghostent shostent ehostent      -- hosts
    gnbyname gnbyaddr gnetent snetent enetent         -- networks
    gpbyname gpbynumber gprotoent sprotoent eprotoent -- protocols
    gsbyname gsbyport gservent sservent eservent      -- services

    gpwnam gpwuid gpwent spwent epwent getlogin       -- users
    ggrnam ggrgid ggrent sgrent egrent                -- groups

=item :browse

A handy tag name for a I<reasonable> default set of ops beyond the
:default optag.  Like :default (and indeed all the other optags) its
current definition is unstable while development continues. It will change.

The :browse tag represents the next step beyond :default. It it a
superset of the :default ops and adds :filesys_read the :sys_db.
The intent being that scripts can access more (possibly sensitive)
information about your system but not be able to change it.

    :default :filesys_read :sys_db

=item :filesys_open

    sysopen open close
    umask binmode

    open_dir closedir -- other dir ops are in :base_io

=item :filesys_write

    link unlink rename symlink truncate

    mkdir rmdir

    utime chmod chown

    fcntl -- not strictly filesys related, but possibly as dangerous?

=item :subprocess

    backtick system

    fork

    wait waitpid

    glob -- access to Cshell via <`rm *`>

=item :ownprocess

    exec exit kill

    time tms -- could be used for timing attacks (paranoid?)

=item :others

This tag holds groups of assorted specialist opcodes that don't warrant
having optags defined for them.

SystemV Interprocess Communications:

    msgctl msgget msgrcv msgsnd

    semctl semget semop

    shmctl shmget shmread shmwrite

=item :load

This tag holds opcodes related to loading modules and getting information
about calling environment and args.

    require dofile 
    caller

=item :still_to_be_decided

    chdir
    flock ioctl

    socket getpeername ssockopt
    bind connect listen accept shutdown gsockopt getsockname

    sleep alarm -- changes global timer state and signal handling
    sort -- assorted problems including core dumps
    tied -- can be used to access object implementing a tie
    pack unpack -- can be used to create/use memory pointers

    entereval -- can be used to hide code from initial compile

    reset

    dbstate -- perl -d version of nextstate(ment) opcode

=item :dangerous

This tag is simply a bucket for opcodes that are unlikely to be used via
a tag name but need to be tagged for completeness and documentation.

    syscall dump chroot

=back

=head1 SEE ALSO

L<ops> -- perl pragma interface to Opcode module.

L<Safe> -- Opcode and namespace limited execution compartments

=head1 AUTHORS

Originally designed and implemented by Malcolm Beattie,
[e-mail] as part of Safe version 1.

Split out from Safe module version 1, named opcode tags and other
changes added by Tim Bunce.

=cut