2005-01-24 22:25:14

by Nick Pollitt

[permalink] [raw]
Subject: Configure mangles hex values


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2005-01-24 22:49:17

by Nick Pollitt

[permalink] [raw]
Subject: Re: Configure mangles hex values

Sorry about previous message.

The hex function in scripts/Configure strips the leading 0x from hex values.
The 0x needs to be there in autoconf.h, and stripping it out causes the
following problematic scenario:

If I start with a hex value in my config file like this:
CONFIG_LOWMEM_SIZE=0x40000000
and then run make oldconfig, it strips out the '0x' so I end up with this:
CONFIG_LOWMEM_SIZE=40000000
Then if I run make xconfig, it doesn't think this is a valid hex value, so it
replaces my value with the default:
CONFIG_LOWMEM_SIZE=0x20000000

The following patch removes the lines that strip out 0x, and inserts the 0x if
appropriate.

--- scripts/Configure.orig 2005-01-24 13:31:55.000000000 -0800
+++ scripts/Configure 2005-01-24 13:34:20.000000000 -0800
@@ -378,15 +378,18 @@
function hex () {
old=$(eval echo "\${$2}")
def=${old:-$3}
- def=${def#*[x,X]}
while :; do
readln "$1 ($2) [$def] " "$def" "$old"
- ans=${ans#*[x,X]}
- if expr "$ans" : '[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
- define_hex "$2" "0x$ans"
+ if expr "$ans" : '0x[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
+ define_hex "$2" "$ans"
break
else
- help "$2"
+ if expr "$ans" : '[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
+ define_hex "$2" "0x$ans"
+ break
+ else
+ help "$2"
+ fi
fi
done
}

2005-01-25 13:09:10

by Marcelo Tosatti

[permalink] [raw]
Subject: Re: Configure mangles hex values



Hi Nick,

Curiosity: What was the reason for stripping the leading 0x?

On Mon, Jan 24, 2005 at 02:41:56PM -0800, Nick Pollitt wrote:
> Sorry about previous message.
>
> The hex function in scripts/Configure strips the leading 0x from hex values.
> The 0x needs to be there in autoconf.h, and stripping it out causes the
> following problematic scenario:
>
> If I start with a hex value in my config file like this:
> CONFIG_LOWMEM_SIZE=0x40000000
> and then run make oldconfig, it strips out the '0x' so I end up with this:
> CONFIG_LOWMEM_SIZE=40000000
> Then if I run make xconfig, it doesn't think this is a valid hex value, so it
> replaces my value with the default:
> CONFIG_LOWMEM_SIZE=0x20000000
>
> The following patch removes the lines that strip out 0x, and inserts the 0x if
> appropriate.
>
> --- scripts/Configure.orig 2005-01-24 13:31:55.000000000 -0800
> +++ scripts/Configure 2005-01-24 13:34:20.000000000 -0800
> @@ -378,15 +378,18 @@
> function hex () {
> old=$(eval echo "\${$2}")
> def=${old:-$3}
> - def=${def#*[x,X]}
> while :; do
> readln "$1 ($2) [$def] " "$def" "$old"
> - ans=${ans#*[x,X]}
> - if expr "$ans" : '[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
> - define_hex "$2" "0x$ans"
> + if expr "$ans" : '0x[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
> + define_hex "$2" "$ans"
> break
> else
> - help "$2"
> + if expr "$ans" : '[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
> + define_hex "$2" "0x$ans"
> + break
> + else
> + help "$2"
> + fi
> fi
> done
> }

2005-01-25 17:26:23

by Nick Pollitt

[permalink] [raw]
Subject: Re: Configure mangles hex values

Hello. I'm thinking that the 0x was stripped for purely cosmetic reasons
rather than anything functional. I had originally thought that the readln
function might need the formatting, but taking a closer look at it now I
don't see any need.

Nick

On Tuesday 25 January 2005 1:20 am, Marcelo Tosatti wrote:
> Hi Nick,
>
> Curiosity: What was the reason for stripping the leading 0x?
>
> On Mon, Jan 24, 2005 at 02:41:56PM -0800, Nick Pollitt wrote:
> > Sorry about previous message.
> >
> > The hex function in scripts/Configure strips the leading 0x from hex
> > values. The 0x needs to be there in autoconf.h, and stripping it out
> > causes the following problematic scenario:
> >
> > If I start with a hex value in my config file like this:
> > CONFIG_LOWMEM_SIZE=0x40000000
> > and then run make oldconfig, it strips out the '0x' so I end up with
> > this: CONFIG_LOWMEM_SIZE=40000000
> > Then if I run make xconfig, it doesn't think this is a valid hex value,
> > so it replaces my value with the default:
> > CONFIG_LOWMEM_SIZE=0x20000000
> >
> > The following patch removes the lines that strip out 0x, and inserts the
> > 0x if appropriate.
> >
> > --- scripts/Configure.orig 2005-01-24 13:31:55.000000000 -0800
> > +++ scripts/Configure 2005-01-24 13:34:20.000000000 -0800
> > @@ -378,15 +378,18 @@
> > function hex () {
> > old=$(eval echo "\${$2}")
> > def=${old:-$3}
> > - def=${def#*[x,X]}
> > while :; do
> > readln "$1 ($2) [$def] " "$def" "$old"
> > - ans=${ans#*[x,X]}
> > - if expr "$ans" : '[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
> > - define_hex "$2" "0x$ans"
> > + if expr "$ans" : '0x[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
> > + define_hex "$2" "$ans"
> > break
> > else
> > - help "$2"
> > + if expr "$ans" : '[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
> > + define_hex "$2" "0x$ans"
> > + break
> > + else
> > + help "$2"
> > + fi
> > fi
> > done
> > }

2005-01-26 01:14:56

by Keith Owens

[permalink] [raw]
Subject: Re: Configure mangles hex values

On Tue, 25 Jan 2005 09:25:57 -0800,
Nick Pollitt <[email protected]> wrote:
>Hello. I'm thinking that the 0x was stripped for purely cosmetic reasons
>rather than anything functional. I had originally thought that the readln
>function might need the formatting, but taking a closer look at it now I
>don't see any need.

Agreed. Apply the patch.