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[Help] [Solution Found] Script on N900 not calculating correctly.

I am having a issue with a script I am trying to write and I just can't work out why it's not working.

The issue is that on my N900 the multiply command on line 47 doesn't multiply correctly.
It however seems to work fine on my Ubuntu desktop which is puzzling me.
I have tried multiple methods to calculate but it just isn't correct.
I am trying to multiply a value by 100 (to get percent) and you can clearly tell that it isn't doing so.

The script is to calculate swap de-fragmentation without needing iostat

Any help will be greatly appreciated. Thanks

Re: [Help] Require help with script on N900.

quickly trying this in N9 at least it works...

~ #
~ # oneh=100 ; getcurrent=123 ; timeshundred=$(($getcurrent*$oneh)) ; echo $timeshundred
12300
~ #

So it seems that N900 has different shell... What does it give as an answer there?

Re: [Help] Require help with script on N900.

Quote:

Originally Posted by juiceme (Post 1301402)

works on the n900 too:

Code:

/home/user # oneh=100 ; getcurrent=123 ;timeshundred=$(($get

current*$oneh)) ; echo $timeshundred

12300

/home/user #

Re: [Help] Require help with script on N900.

Okaay, then there is no other possibility than for some reason $getcurrent does not evaluate to a number.

Re: [Help] Require help with script on N900.

Did you try the same script in bash? There are some minor differences between ash and bash ;)

Try to run the script from bash, need to have bash3 (packagename) installed though.

Re: [Help] Require help with script on N900.

No idea why it wouldn't work. Maybe try replacing timeshundred formula with $(expr $oneh \* $getcurrent) ?

Re: [Help] Require help with script on N900.

Quote:

Originally Posted by thedead1440 (Post 1301403)

works on the n900 too:

Code:

/home/user # oneh=100 ; getcurrent=123 ;timeshundred=$(($get

current*$oneh)) ; echo $timeshundred

12300

/home/user #

Okay so a completely fresh script on the N900 in question with the above works.
So is there something I have done further back in the script that is effecting it?

I have tried "let" and "expr" style claculations with the same results.
I also originally tried just putting "$getcurrent*100" and got the issue.

Installing bash now to see if it makes a difference.

Re: [Help] [Solution Found] Require help with script not working correctly on N900.

Quote:

Originally Posted by mr_pingu (Post 1301417)

Did you try the same script in bash? There are some minor differences between ash and bash ;)

Try to run the script from bash, need to have bash3 (packagename) installed though.

Bash3 installed.
Changed to #!/bin/bash
Works a treat, thank you.
Is this a bug in ash/busybox?
Is there another way of doing this so my application doesn't depend on bash3?

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

Not a bug of busybox, more of a feature which most of us don't like. Remember busybox is written in mind to be used on embedded devices so basically it's a stripped down version of bash.

It would probably possible to rewrite without the dependence on bash but then you should knock on somebody else door. I am not a good coder/scripter.

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

Quote:

Originally Posted by mr_pingu (Post 1301452)

Remember busybox is written in mind to be used on embedded devices so basically it's a stripped down version of bash.

Seems odd to make it calculate a simple multiplication incorrectly. I can understand stripping commands to make a lightweight version. Making commands not work correctly is plain stupid IMO.

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

What is the output of $getcurrent during execution?
I would also guess anon-numeric string?
Or what is the error message. Or full output of script.

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

good point but AFAIK it doesn't support all the typical calculation shizzle :( However you could use the "dc" applet delivered with busybox

Code:

 dc --help

BusyBox v1.20.2 (Debian 1.20.2power4+thumb0) multi-call binary.



Usage: dc EXPRESSION...



Tiny RPN calculator. Operations:

+, add, -, sub, *, mul, /, div, %, mod, **, exp, and, or, not, eor,

p - print top of the stack (without popping),

f - print entire stack,

o - pop the value and set output radix (must be 10, 16, 8 or 2).

Examples: 'dc 2 2 add p' -> 4, 'dc 8 8 * 2 2 + / p' -> 16

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

Quote:

Originally Posted by peterleinchen (Post 1301458)

Or what is the error message. Or full output of script.

BASH

Code:

/media/mmc1 $ bash swapblocks.sh 

261896 ublocks

134090752 ubytes

130948 ukbytes, 127 umbytes, 0 ugbytes

838852608 totalswapbytes

1 lasttotalsb

134090751 getcurrent

13409075100 timeshundred

15 % Swap Fragmented

ASH

Code:

/media/mmc1 $ sh swapblocks.sh   

261896 ublocks

134090752 ubytes

130948 ukbytes, 127 umbytes, 0 ugbytes

838852608 totalswapbytes

1 lasttotalsb

134090751 getcurrent

524173212 timeshundred

0 % Swap Fragmented

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

Quote:

Originally Posted by mr_pingu (Post 1301467)

However you could use the "dc" applet delivered with busybox

Not an option, bbpower only function.

Code:

dc --help

-sh: dc: not found

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

int32!

Do your calc not as byte, but as kB or MB (not that exact, but hey you also do not round the percentage ;))

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

Add.: @peterleinchen beat me!

Quote:

Originally Posted by sixwheeledbeast (Post 1301468)

BASH

Code:

/media/mmc1 $ bash swapblocks.sh 

261896 ublocks

134090752 ubytes

130948 ukbytes, 127 umbytes, 0 ugbytes

838852608 totalswapbytes

1 lasttotalsb

134090751 getcurrent

13409075100 timeshundred

15 % Swap Fragmented

ASH

Code:

/media/mmc1 $ sh swapblocks.sh   

261896 ublocks

134090752 ubytes

130948 ukbytes, 127 umbytes, 0 ugbytes

838852608 totalswapbytes

1 lasttotalsb

134090751 getcurrent

524173212 timeshundred

0 % Swap Fragmented

524173212 is ((134090751 * 100) mod 2*1024**3), meaning busybox does only 32-bit signed arithmetic.

Didn't look at the script, but I guess that whenever you read values that are expected to overflow a signed 32-bit number, you should do some kind of "renormalization" (e.g. divide by 1000, or by 1000000, as appropriate), and keep track of the "multiplier" in another variable. If you really need it, that is.

Don't know at the moment if dc or bc are included in busybox(-power), but AWK is always there, and does (or should do) the job correctly.

Re: [Help] [Solution Found] Script on N900 not calculating correctly.

Thank you all. Makes sense now.
Here's the fixed script and output, for anybody interested.
Should be able to use in FlopSwap now.

Code:

#!/bin/sh



# Setup notification banner

banner(){

o=org

f=freedesktop

n=Notifications

run-standalone.sh dbus-send --type=method_call \

--dest=$o.$f.$n /$o/$f/$n $o.$f.$n.SystemNoteInfoprint string:"$1"

}



# Setup notification dialog

dialog(){

o=org

f=freedesktop

n=Notifications

run-standalone.sh dbus-send --type=method_call \

--dest=$o.$f.$n /$o/$f/$n $o.$f.$n.SystemNoteDialog string:"$1" uint32: string:

}



#Get current swap from /proc/swaps

disk=$(cat /proc/swaps | awk '/dev/ {print $1}' | cut -d "/" -f 3)

#Get blocks used since boot from /proc/diskstats

ublocks=$(awk '{if ($3=="'"$disk"'") print $10}' /proc/diskstats)

echo $ublocks ublocks

#Multiply blocks by 512 to get used bytes

ubytes=$(($ublocks*512))

#Calculate used bytes into Kb, Mb and Gb

echo $ubytes ubytes

ukbytes=$(($ubytes/1024))

umbytes=$(($ubytes/1024/1024))

ugbytes=$(($ubytes/1024/1024/1024))

echo $ukbytes ukbytes, $umbytes umbytes, $ugbytes ugbytes

#Get Swap size from /proc/swaps

swapsize=$(awk '{if ($1=="'"/dev/$disk"'") print $3}' /proc/swaps)

#Divide by 1024 to get swap size in megabytes

swapsizembytes=$(($swapsize/1024))

echo $swapsizembytes swapsizembytes

#Get last megabytes value from /tmp folder

lasttotalsmb=$(cat /tmp/flopswaplast | awk '{print $1}')

echo $lasttotalsmb lasttotalsmb

#Subtract last from current value to get latest used value

getcurrent=$(($umbytes-$lasttotalsmb))

echo $getcurrent getcurrent

timeshundred=$(($getcurrent*100))

echo $timeshundred timeshundred

#Get divide to get percent

getpercent=$(($timeshundred/$swapsizembytes))

echo $getpercent % Fresh Swap Written

#Print banner

banner "$getpercent % Fresh Swap Written

$getcurrent Mb of $swapsizembytes Mb"

#If 94% show warning dialog

if [ $getpercent -ge 94 ]; then

dialog "



***Fresh Swap Recommended***

Used \"$getcurrent Mb ($getpercent)\" of \"$swapsizembytes Mb\"

Device $(hostname) on $(date)



"

fi

Code:

/media/mmc1 $ sh swapblocks.sh 

262984 ublocks

134647808 ubytes

131492 ukbytes, 128 umbytes, 0 ugbytes

799 swapsizembytes

1 lasttotalsmb

127 getcurrent

12700 timeshundred

15 % Fresh Swap Written