Commit da70ee1f authored by Fred Drake's avatar Fred Drake

Use methoddesc and memberdesc, as needed.

Added description of BastionClass, since it is referred to in the Bastion
description as subclassable.
parent 182bd2d1
\section{Standard Module \sectcode{Bastion}}
\label{module-Bastion}
\stmodindex{Bastion}
\setindexsubitem{(in module Bastion)}
% I'm concerned that the word 'bastion' won't be understood by people
% for whom English is a second language, making the module name
......@@ -17,7 +16,8 @@ other, unsafe attributes.
% I've punted on the issue of documenting keyword arguments for now.
\begin{funcdesc}{Bastion}{object\optional{, filter, name, class}}
\begin{funcdesc}{Bastion}{object\optional{, filter\optional{,
name\optional{, class}}}}
Protect the object \var{object}, returning a bastion for the
object. Any attempt to access one of the object's attributes will
have to be approved by the \var{filter} function; if the access is
......@@ -32,8 +32,17 @@ will be \samp{<Bastion for \var{name}>} if a value for
\var{name} is provided; otherwise, \samp{repr(\var{object})} will be
used.
\var{class}, if present, would be a subclass of \class{BastionClass};
\var{class}, if present, should be a subclass of \class{BastionClass};
see the code in \file{bastion.py} for the details. Overriding the
default \class{BastionClass} will rarely be required.
\end{funcdesc}
\begin{classdesc}{BastionClass}{getfunc, name}
Class which actually implements bastion objects. This is the default
class used by \function{Bastion()}. The \var{getfunc} parameter is a
function which returns the value of an attribute which should be
exposed to the restricted execution environment when called with the
name of the attribute as the only parameter. \var{name} is used to
construct the \function{repr()} of the \class{BastionClass} instance.
\end{classdesc}
......@@ -50,8 +50,7 @@ instance won't have any effect; instead, create a subclass of
Instances of the new class will then use those new values. All these
attributes are tuples of strings.
\setindexsubitem{(RExec object attribute)}
\begin{datadesc}{nok_builtin_names}
\begin{memberdesc}{nok_builtin_names}
Contains the names of built-in functions which will \emph{not} be
available to programs running in the restricted environment. The
value for \class{RExec} is \code{('open',} \code{'reload',}
......@@ -61,9 +60,9 @@ override this variable should probably start with the value from the
base class and concatenate additional forbidden functions --- when new
dangerous built-in functions are added to Python, they will also be
added to this module.)
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_builtin_modules}
\begin{memberdesc}{ok_builtin_modules}
Contains the names of built-in modules which can be safely imported.
The value for \class{RExec} is \code{('audioop',} \code{'array',}
\code{'binascii',} \code{'cmath',} \code{'errno',} \code{'imageop',}
......@@ -72,16 +71,16 @@ The value for \class{RExec} is \code{('audioop',} \code{'array',}
\code{'strop',} \code{'struct',} \code{'time')}. A similar remark
about overriding this variable applies --- use the value from the base
class as a starting point.
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_path}
\begin{memberdesc}{ok_path}
Contains the directories which will be searched when an \keyword{import}
is performed in the restricted environment.
The value for \class{RExec} is the same as \code{sys.path} (at the time
the module is loaded) for unrestricted code.
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_posix_names}
\begin{memberdesc}{ok_posix_names}
% Should this be called ok_os_names?
Contains the names of the functions in the \module{os} module which will be
available to programs running in the restricted environment. The
......@@ -90,68 +89,69 @@ value for \class{RExec} is \code{('error',} \code{'fstat',}
\code{'times',} \code{'uname',} \code{'getpid',} \code{'getppid',}
\code{'getcwd',} \code{'getuid',} \code{'getgid',} \code{'geteuid',}
\code{'getegid')}.
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_sys_names}
\begin{memberdesc}{ok_sys_names}
Contains the names of the functions and variables in the \module{sys}
module which will be available to programs running in the restricted
environment. The value for \class{RExec} is \code{('ps1',}
\code{'ps2',} \code{'copyright',} \code{'version',} \code{'platform',}
\code{'exit',} \code{'maxint')}.
\end{datadesc}
\end{memberdesc}
\class{RExec} instances support the following methods:
\setindexsubitem{(RExec object method)}
\begin{funcdesc}{r_eval}{code}
\begin{methoddesc}{r_eval}{code}
\var{code} must either be a string containing a Python expression, or
a compiled code object, which will be evaluated in the restricted
environment's \module{__main__} module. The value of the expression or
code object will be returned.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_exec}{code}
\begin{methoddesc}{r_exec}{code}
\var{code} must either be a string containing one or more lines of
Python code, or a compiled code object, which will be executed in the
restricted environment's \module{__main__} module.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_execfile}{filename}
\begin{methoddesc}{r_execfile}{filename}
Execute the Python code contained in the file \var{filename} in the
restricted environment's \module{__main__} module.
\end{funcdesc}
\end{methoddesc}
Methods whose names begin with \samp{s_} are similar to the functions
beginning with \samp{r_}, but the code will be granted access to
restricted versions of the standard I/O streams \code{sys.stdin},
\code{sys.stderr}, and \code{sys.stdout}.
\begin{funcdesc}{s_eval}{code}
\begin{methoddesc}{s_eval}{code}
\var{code} must be a string containing a Python expression, which will
be evaluated in the restricted environment.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_exec}{code}
\begin{methoddesc}{s_exec}{code}
\var{code} must be a string containing one or more lines of Python code,
which will be executed in the restricted environment.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_execfile}{code}
\begin{methoddesc}{s_execfile}{code}
Execute the Python code contained in the file \var{filename} in the
restricted environment.
\end{funcdesc}
\end{methoddesc}
\class{RExec} objects must also support various methods which will be
implicitly called by code executing in the restricted environment.
Overriding these methods in a subclass is used to change the policies
enforced by a restricted environment.
\begin{funcdesc}{r_import}{modulename\optional{, globals, locals, fromlist}}
\begin{methoddesc}{r_import}{modulename\optional{, globals\optional{,
locals\optional{, fromlist}}}}
Import the module \var{modulename}, raising an \exception{ImportError}
exception if the module is considered unsafe.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_open}{filename\optional{, mode\optional{, bufsize}}}
\begin{methoddesc}{r_open}{filename\optional{, mode\optional{, bufsize}}}
Method called when \function{open()} is called in the restricted
environment. The arguments are identical to those of \function{open()},
and a file object (or a class instance compatible with file objects)
......@@ -159,32 +159,33 @@ should be returned. \class{RExec}'s default behaviour is allow opening
any file for reading, but forbidding any attempt to write a file. See
the example below for an implementation of a less restrictive
\method{r_open()}.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_reload}{module}
\begin{methoddesc}{r_reload}{module}
Reload the module object \var{module}, re-parsing and re-initializing it.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_unload}{module}
\begin{methoddesc}{r_unload}{module}
Unload the module object \var{module} (i.e., remove it from the
restricted environment's \code{sys.modules} dictionary).
\end{funcdesc}
\end{methoddesc}
And their equivalents with access to restricted standard I/O streams:
\begin{funcdesc}{s_import}{modulename\optional{, globals, locals, fromlist}}
\begin{methoddesc}{s_import}{modulename\optional{, globals\optional{,
locals\optional{, fromlist}}}}
Import the module \var{modulename}, raising an \exception{ImportError}
exception if the module is considered unsafe.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_reload}{module}
\begin{methoddesc}{s_reload}{module}
Reload the module object \var{module}, re-parsing and re-initializing it.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_unload}{module}
\begin{methoddesc}{s_unload}{module}
Unload the module object \var{module}.
% XXX what are the semantics of this?
\end{funcdesc}
\end{methoddesc}
\subsection{An example}
......
\section{Standard Module \sectcode{Bastion}}
\label{module-Bastion}
\stmodindex{Bastion}
\setindexsubitem{(in module Bastion)}
% I'm concerned that the word 'bastion' won't be understood by people
% for whom English is a second language, making the module name
......@@ -17,7 +16,8 @@ other, unsafe attributes.
% I've punted on the issue of documenting keyword arguments for now.
\begin{funcdesc}{Bastion}{object\optional{, filter, name, class}}
\begin{funcdesc}{Bastion}{object\optional{, filter\optional{,
name\optional{, class}}}}
Protect the object \var{object}, returning a bastion for the
object. Any attempt to access one of the object's attributes will
have to be approved by the \var{filter} function; if the access is
......@@ -32,8 +32,17 @@ will be \samp{<Bastion for \var{name}>} if a value for
\var{name} is provided; otherwise, \samp{repr(\var{object})} will be
used.
\var{class}, if present, would be a subclass of \class{BastionClass};
\var{class}, if present, should be a subclass of \class{BastionClass};
see the code in \file{bastion.py} for the details. Overriding the
default \class{BastionClass} will rarely be required.
\end{funcdesc}
\begin{classdesc}{BastionClass}{getfunc, name}
Class which actually implements bastion objects. This is the default
class used by \function{Bastion()}. The \var{getfunc} parameter is a
function which returns the value of an attribute which should be
exposed to the restricted execution environment when called with the
name of the attribute as the only parameter. \var{name} is used to
construct the \function{repr()} of the \class{BastionClass} instance.
\end{classdesc}
......@@ -50,8 +50,7 @@ instance won't have any effect; instead, create a subclass of
Instances of the new class will then use those new values. All these
attributes are tuples of strings.
\setindexsubitem{(RExec object attribute)}
\begin{datadesc}{nok_builtin_names}
\begin{memberdesc}{nok_builtin_names}
Contains the names of built-in functions which will \emph{not} be
available to programs running in the restricted environment. The
value for \class{RExec} is \code{('open',} \code{'reload',}
......@@ -61,9 +60,9 @@ override this variable should probably start with the value from the
base class and concatenate additional forbidden functions --- when new
dangerous built-in functions are added to Python, they will also be
added to this module.)
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_builtin_modules}
\begin{memberdesc}{ok_builtin_modules}
Contains the names of built-in modules which can be safely imported.
The value for \class{RExec} is \code{('audioop',} \code{'array',}
\code{'binascii',} \code{'cmath',} \code{'errno',} \code{'imageop',}
......@@ -72,16 +71,16 @@ The value for \class{RExec} is \code{('audioop',} \code{'array',}
\code{'strop',} \code{'struct',} \code{'time')}. A similar remark
about overriding this variable applies --- use the value from the base
class as a starting point.
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_path}
\begin{memberdesc}{ok_path}
Contains the directories which will be searched when an \keyword{import}
is performed in the restricted environment.
The value for \class{RExec} is the same as \code{sys.path} (at the time
the module is loaded) for unrestricted code.
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_posix_names}
\begin{memberdesc}{ok_posix_names}
% Should this be called ok_os_names?
Contains the names of the functions in the \module{os} module which will be
available to programs running in the restricted environment. The
......@@ -90,68 +89,69 @@ value for \class{RExec} is \code{('error',} \code{'fstat',}
\code{'times',} \code{'uname',} \code{'getpid',} \code{'getppid',}
\code{'getcwd',} \code{'getuid',} \code{'getgid',} \code{'geteuid',}
\code{'getegid')}.
\end{datadesc}
\end{memberdesc}
\begin{datadesc}{ok_sys_names}
\begin{memberdesc}{ok_sys_names}
Contains the names of the functions and variables in the \module{sys}
module which will be available to programs running in the restricted
environment. The value for \class{RExec} is \code{('ps1',}
\code{'ps2',} \code{'copyright',} \code{'version',} \code{'platform',}
\code{'exit',} \code{'maxint')}.
\end{datadesc}
\end{memberdesc}
\class{RExec} instances support the following methods:
\setindexsubitem{(RExec object method)}
\begin{funcdesc}{r_eval}{code}
\begin{methoddesc}{r_eval}{code}
\var{code} must either be a string containing a Python expression, or
a compiled code object, which will be evaluated in the restricted
environment's \module{__main__} module. The value of the expression or
code object will be returned.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_exec}{code}
\begin{methoddesc}{r_exec}{code}
\var{code} must either be a string containing one or more lines of
Python code, or a compiled code object, which will be executed in the
restricted environment's \module{__main__} module.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_execfile}{filename}
\begin{methoddesc}{r_execfile}{filename}
Execute the Python code contained in the file \var{filename} in the
restricted environment's \module{__main__} module.
\end{funcdesc}
\end{methoddesc}
Methods whose names begin with \samp{s_} are similar to the functions
beginning with \samp{r_}, but the code will be granted access to
restricted versions of the standard I/O streams \code{sys.stdin},
\code{sys.stderr}, and \code{sys.stdout}.
\begin{funcdesc}{s_eval}{code}
\begin{methoddesc}{s_eval}{code}
\var{code} must be a string containing a Python expression, which will
be evaluated in the restricted environment.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_exec}{code}
\begin{methoddesc}{s_exec}{code}
\var{code} must be a string containing one or more lines of Python code,
which will be executed in the restricted environment.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_execfile}{code}
\begin{methoddesc}{s_execfile}{code}
Execute the Python code contained in the file \var{filename} in the
restricted environment.
\end{funcdesc}
\end{methoddesc}
\class{RExec} objects must also support various methods which will be
implicitly called by code executing in the restricted environment.
Overriding these methods in a subclass is used to change the policies
enforced by a restricted environment.
\begin{funcdesc}{r_import}{modulename\optional{, globals, locals, fromlist}}
\begin{methoddesc}{r_import}{modulename\optional{, globals\optional{,
locals\optional{, fromlist}}}}
Import the module \var{modulename}, raising an \exception{ImportError}
exception if the module is considered unsafe.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_open}{filename\optional{, mode\optional{, bufsize}}}
\begin{methoddesc}{r_open}{filename\optional{, mode\optional{, bufsize}}}
Method called when \function{open()} is called in the restricted
environment. The arguments are identical to those of \function{open()},
and a file object (or a class instance compatible with file objects)
......@@ -159,32 +159,33 @@ should be returned. \class{RExec}'s default behaviour is allow opening
any file for reading, but forbidding any attempt to write a file. See
the example below for an implementation of a less restrictive
\method{r_open()}.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_reload}{module}
\begin{methoddesc}{r_reload}{module}
Reload the module object \var{module}, re-parsing and re-initializing it.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{r_unload}{module}
\begin{methoddesc}{r_unload}{module}
Unload the module object \var{module} (i.e., remove it from the
restricted environment's \code{sys.modules} dictionary).
\end{funcdesc}
\end{methoddesc}
And their equivalents with access to restricted standard I/O streams:
\begin{funcdesc}{s_import}{modulename\optional{, globals, locals, fromlist}}
\begin{methoddesc}{s_import}{modulename\optional{, globals\optional{,
locals\optional{, fromlist}}}}
Import the module \var{modulename}, raising an \exception{ImportError}
exception if the module is considered unsafe.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_reload}{module}
\begin{methoddesc}{s_reload}{module}
Reload the module object \var{module}, re-parsing and re-initializing it.
\end{funcdesc}
\end{methoddesc}
\begin{funcdesc}{s_unload}{module}
\begin{methoddesc}{s_unload}{module}
Unload the module object \var{module}.
% XXX what are the semantics of this?
\end{funcdesc}
\end{methoddesc}
\subsection{An example}
......
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