Re: Concatenating/inserting strings with backslashes
Brian Candler wrote: > Here's something weird. I'm trying to concatenate some strings which contain > (i.e. not a newline). Well... that's all pretty hacky. It's made worse by Reply-Message being automatically expanded, whereas other attributes aren't. Try your tests below using Filter-Id, and they will be different. The server has grown over the years in a fairly ad-hoc way. I welcome suggestions for sanitizing how it deals with string. Alan DeKok. - List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html
RE: Concatenating/inserting strings with backslashes
> Brian Candler wrote
>
> > try:
> >
> > if (%{reply:Reply-Message} =~ /(.*)/) {
> >update reply {
> > Reply-Message = "stuff %{1}"
> >}
> > }
>
> Nice idea, but it appears to suffer the same expansion problem.
>
> As you have written it gives this error:
>
> Bare %{...} is invalid in condition at: %{reply:Reply-Message} =~ /(.*)/)
>
> Adding the double quotes:
Oh right.
I usually do this with e.g. User-Name without having to specify the attribute
list
explicitly; I forget whether syntax works to do that with a raw variable.
I know outer.VarName works raw, so maybe just reply:Reply-Message
without the braces or quotes?
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Re: Concatenating/inserting strings with backslashes
> try:
>
> if (%{reply:Reply-Message} =~ /(.*)/) {
>update reply {
> Reply-Message = "stuff %{1}"
>}
> }
Nice idea, but it appears to suffer the same expansion problem.
As you have written it gives this error:
Bare %{...} is invalid in condition at: %{reply:Reply-Message} =~ /(.*)/)
Adding the double quotes:
update reply {
Reply-Message := "foo"
}
if ("%{reply:Reply-Message}" =~ /(.*)/) {
update reply {
Reply-Message := "%{1}nbar"
}
}
if ("%{reply:Reply-Message}" =~ /(.*)/) {
update reply {
Reply-Message := "%{1}nbaz"
}
}
This gives foo bar baz
update reply {
Reply-Message := "foo"
}
if ("%{reply:Reply-Message}" =~ /(.*)/) {
update reply {
Reply-Message := "%{1}nbar"
}
}
if ("%{reply:Reply-Message}" =~ /(.*)/) {
update reply {
Reply-Message := "%{1}nbaz"
}
}
This gives foo bar baz
Regards,
Brian.
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Re: Concatenating/inserting strings with backslashes
On 09/11/12 15:39, Brian Candler wrote:
Here's something weird. I'm trying to concatenate some strings which contain
(i.e. not a newline).
Uh oh... here be dragons!
In a normal string literal, I have to enter four backslashes:
update reply {
Reply-Message := "anb"
}
("\\n" gives a newline, "\\\n" gives backslash followed by newline)
Yeah; I think there is a similar thing happening here to the regexp
stuff I discussed on -devel recently.
I think what happens in the code is this:
1. lib/token.c:gettoken loads the config file and performs backslash
processing on any quoted strings
2. conffile.c:cf_pairtovp loads the VP update list at config load
time, and sets the "do_xlat" flag on any that are double-quoted
3. modcall.c:modcall calls radius_update_attrlist
4. evaluate.c:radius_update_attrlist checks the "do_xlat" flag on the
VP, which was set at config load, and calls expand_string (which calls
radius_xlat) followed by pairparsevalue.
The net effect is that:
update x {
Foo = "an"
}
...is de-escaped many times:
* into "an" by the gettoken / config file loader
* into "an" by radius_xlat
* into "a" by pairparsevalue (on the result of radius_xlat)
This kind of thing is pretty common - exim has a similar problem. It's
difficult to know what to do about it in a manner that's universally
satisfactory.
One solution is to not process "\x" anywhere except loading from config
files, but that's likely a very significant backwards compatibility
break... you also might *want* to provide a way for people to interpret
escapes again (though this can be done with an xlat e.g.
"%{unescape:%{something-that-returns-backslash-n}}" == ""
Others options exist. Personally I find the existing behaviour quite
surprising, but it's also something I very seldom run into, so don't
worry too much about.
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RE: Concatenating/inserting strings with backslashes
> Brian Candler writes:
> Or is there another way I can concatenate strings, which doesn't involve
> expanding them into another string?
The workaround I've used for this is to feed the value through a regexp
match to get it into %{1}, which does not seem to be subject to unescaping.
try:
if (%{reply:Reply-Message} =~ /(.*)/) {
update reply {
Reply-Message = "stuff %{1}"
}
}
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Concatenating/inserting strings with backslashes
Here's something weird. I'm trying to concatenate some strings which contain
(i.e. not a newline).
In a normal string literal, I have to enter four backslashes:
update reply {
Reply-Message := "anb"
}
("\\n" gives a newline, "\\\n" gives backslash followed by newline)
But when I try to insert one string into another it goes completely haywire.
update reply {
Reply-Message := "foonbar"
}
update reply {
Reply-Message := "%{reply:Reply-Message}nbaz"
}
This gives me "foo" "bar" "baz". That is, even the
second n is being collapsed into a newline!
Some more test cases:
update reply {
Reply-Message := "foonbar"
}
update reply {
Reply-Message := "quxnbaz"
}
correctly gives me "qux" "baz"
update reply {
Reply-Message := "foonbar"
}
update reply {
Reply-Message := "%{Wibble:-qux}nbaz"
}
gives me "baz". In fact, I need *eight* backslashes to get a
literal backslash here:
Reply-Message := "%{Wibble:-qux}nbaz"
So somehow, the presence of a string expansion within a string affects the
interpretation of subsequent backslashes within that string.
Now, this works:
update reply {
Reply-Message := "foonbar"
}
update reply {
Reply-Message := "%{reply:Reply-Message}nbaz"
}
But then if I do another layer of string insertion they get translated to
newlines again.
update reply {
Reply-Message := "foonbar"
}
update reply {
Reply-Message := "%{reply:Reply-Message}nbaz"
}
update reply {
Reply-Message := "%{reply:Reply-Message}"
}
This seems pretty broken to me, but if someone would care to explain how to
deal with it, please do.
Or is there another way I can concatenate strings, which doesn't involve
expanding them into another string?
Thanks,
Brian.
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