I am trying to investigate an access violation issue in code. As you can see some of the value for address contains apostrophe character (like in 7fb`80246000).
0:000> !address -summary
--- Usage Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
Free 424 7fb`80246000 ( 7.982 Tb) 99.78%
The tick mark (grave accent) is just used to separate the lower 4 bytes from the higher 4 bytes of a 64-bit number.
7fb`80246000
is the same as
0x7fb80246000
It is purely for visual aesthetics (making the value easier to parse by humans).
Related
I am interested in the maximum length of the header name, header value.
And are there any restrictions on the maximum number of parameters?
None of the relevant specifications define a maximum length for a header name or value, but rfc5321 section 4.5.3.1.6 states that the maximum line length is 1000 octets (aka 1000 bytes) including the terminating <CR><LF> sequence.
How does that affect maximum header name/value lengths, you might ask?
It doesn't affect the maximum header value length at all because rfc5322 section 3.2.2 defines CFWS (Comment Folding WhiteSpace) which is further used in the BNF grammar definitions for headers, which basically allows header values to be infinite in length.
That said, while there is no explicit maximum length for a header field name, there is a practical one.
The maximum line length is 1000 octets (including the terminating <CR><LF> sequence).
The recommended maximum line length is 78 octets (see rfc5322 section 2.1.1).
The syntactical definition of a header looks like this:
optional-field = field-name ":" unstructured CRLF
field-name = 1*ftext
ftext = %d33-57 / ; Printable US-ASCII
%d59-126 ; characters not including
; ":".
(where optional-field is any header field that is not pre-defined in the specification such as "To", "From", "Date", "Subject", etc). This syntax definition can be found in rfc5322 section 3.6.8.
Header field names cannot be folded (as seen by the syntax definition).
Since it must be possible to represent a header field name and the colon (":") all within 998 bytes (1000 bytes minus the <CR><LF> sequence), we can safely conclude that the maximum length of a header field name is 997 bytes (or, since header field names are constrained to US-ASCII, 997 characters) and SHOULD be constrained to fit within a recommended maximum line length of 78 bytes, meaning the maximum header field name SHOULD be a maximum of 77 bytes/characters.
One thing that makes me particularly like about Smalltalk is that it
has the power to do arithemtic calculations of numbers with the base
of different integers. I guess no other language can do the same.
Please see the codes below.
Transcript show: 16raf * 32; cr.
Transcript show: 7r21 - 5r32; cr.
The output is
5600
-2
I understand that if the number is hexadecimal(16-based), abcdef can
be employed. But what if the integer I want to be the base is 250. On some position, there's 60. How can I type that number in squeak ?
Short answer: you cannot type arbitrary numbers for arbitrary bases above 36 without changing the parser.
Longer answer:
You can use arbitrary base above 36, but you will run into trouble print and write numbers that would need symbols above 36.
You can check all the symbols for a base:
base := 36.
number := 0.
1 to: base - 1 do: [ :i |
number := number * base + i
].
number printStringBase: base.
the above results in the following
'123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
This is also hard-coded when printing in SmallInteger>>printOn:base:length:padded:
Note that for a number that is smaller than base, printStringBase: will just use ascii directly.
36 printStringBase: 37 '['
But even if you were to remove the hardcoded limitation and used ascii directly, you aren't helping yourself.
Sooner or later you will need ascii symbols that have different meaning in the syntax. For example following Z (ascii 90) is [ (ascii 91), which is used to start block.
So 37r2[ will be parsed into 37r2 and [ will be reserved for block (and thus will result in syntax error).
But otherwise you can use any base
2001rSpaceOdyssey -> 57685915098460127668088707185846682264
I have a quick question. Its most likely user error so I apologize before I begin.
I’m trying to setup threshold for a device so that it will alert us when one of our printers is in a certain state. (Jammed, out of toner, no paper etc) I’ve found the specific oid that handles this. (1.3.6.1.2.1.25.3.5.1.2.1) The specific oid is called hrPrinterDetectedErrorState under the HOST-RESOURCE-MIB. I’ve verified that I can see the oid via SNMPWALK. My problem is interpreting the data its spitting out. What i'm reading in the MIB and what i'm seeing via SNMPWALK are different.
Here is the description of oid from the MIB:
"This object represents any error conditions detected
by the printer. The error conditions are encoded as
bits in an octet string, with the following
definitions:
Condition Bit #
lowPaper 0
noPaper 1
lowToner 2
noToner 3
doorOpen 4
jammed 5
offline 6
serviceRequested 7
inputTrayMissing 8
outputTrayMissing 9
markerSupplyMissing 10
outputNearFull 11
outputFull 12
inputTrayEmpty 13
overduePreventMaint 14
Bits are numbered starting with the most significant
bit of the first byte being bit 0, the least
significant bit of the first byte being bit 7, the
most significant bit of the second byte being bit 8,
and so on. A one bit encodes that the condition was
detected, while a zero bit encodes that the condition
was not detected.
This object is useful for alerting an operator to
specific warning or error conditions that may occur,
especially those requiring human intervention."
The odd part is that SNMPWALK says the oid is a Hex-String while the MIB specifies that it should be a Octet-String. Are the two different? Do I need to convert the data that is output by SNMPWALK somehow to get it to match up with what the MIB is saying?
To test everything, I put the printer into several different “States.” I then ran an SNMPWALK on the device to see what the oid output. Here are the results. As you will see, these results don’t match up to what the MIB specifies.
Case 1: Opened the toner door
Expected Output based on MIB: 4
SNMP Output: 08
Case 2: Removed Toner & Closed the door
Expected Output based on MIB: 1
SNMP Output: 10
Case 3: Placed 1 sheet of paper and printed a 2 page document. The printer ran out of paper.
Expected Output based on MIB: 0 or 1
SNMP Output: #
I’m confused at the output. I just need to know how to read the oid so I can setup thresholds so that when it sees, for example, a 08 it performs a certain action.
Thanks for your help!
You are reading this wrong. The data you receive back should actually be interpreted as a bit array and every bit is its own value for the specific alarm in your case
Expected Output based on MIB: 4
SNMP Output: 08
You actually get back the output:
00001000 00000000
The first byte here covers those values
lowPaper 0
noPaper 1
lowToner 2
noToner 3
doorOpen 4
jammed 5
offline 6
serviceRequested 7
So lowPaper is bit 0, noPaper is bit 1, lowToner is bit 2, etc. And doorOpen is bit 4 and as you can see that bit is set, indicating that the door is open.
EDIT:
This is very dependent on the device and implementation. To know how to parse it right involves a lot of trial and error (at least from my experience). As an example if you get back the message 9104, this could be either be
91 and 04 are separate so you first translate 91 to binary from hex and then the
same thing with 04
91: 10010001
04: 00000100
Which would mean low paper, noToner, service requested and inputTrayEmpty. This looks like the most likely way this works.
If you only get one byte back this then means you should only look for alarms in the first 8 bits. As a example of things you need to look out for: If the only alarm present is doorOpen you could be getting back only 08 but it would actually be 0008 where the first 2 hex chars are actually the second part of the alarms but aren't shown because they are none present. So in your case you actually first have to switch the bytes (if there are 4) parse the first two and the second two on their own and then you get the actual result.
As I said there is no real standard here from what i have seen and you have to just work with it until you are sure you know how the data is sent and how to parse it.
Powershell function to interpret the hrPrinterDetectedErrorState octetstring. (I feel like there's some more often used way to do this?) I've been using this module, but it doesn't even resolve hostnames to ip addresses.
The data property returned is just a string not an octetstring type. None of the printers are snmp v3.
https://www.powershellgallery.com/packages/SNMP/1.0.0.1
A single byte would have to be padded with a zero. Most of the time only one byte is sent. The bytes are in the, I think confusing, order that it's documented in. Converting two bytes to an integer results in a different order (depending on big endian or little endian order).
function snmpmessage {
param($data)
[flags()] Enum hrPrinterDetectedErrorState
{
# more common group
LowPaper = 0x0080
NoPaper = 0x0040
LowToner = 0x0020
NoToner = 0x0010
DoorOpen = 0x0008
Jammed = 0x0004
Offline = 0x0002
ServiceRequested = 0x0001
InputTrayMissing = 0x8000
OutputTrayMissing = 0x4000
MarkerSupplyMissing = 0x2000
OutputNearFull = 0x1000
OutputFull = 0x0800
InputTrayEmpty = 0x0400
OverduePreventMaint = 0x0200
}
$bytes = [byte[]][char[]]$data
if ($bytes.count -eq 1) { $bytes = $bytes[0],0 } # pad 0
$code = [bitconverter]::ToUInt16($bytes, ($startIndex=0))
[hrPrinterDetectedErrorState]$code
}
snmpmessage -join [char[]](1,4)
ServiceRequested, InputTrayEmpty
snmpmessage '#' # 0x40
NoPaper
Or:
$hrPrinterDetectedErrorState = '1.3.6.1.2.1.25.3.5.1.2.1'
$hostname = 'myprinter01'
$ip = (Resolve-DnsName $hostname).ipaddress
$result = Get-SnmpData -ip $ip -oid $hrPrinterDetectedErrorState -v v1
snmpmessage $result.data
LowToner
# ?
# $octetstring = [Lextm.SharpSnmpLib.OctetString]::new($result.data)
In windbg, I can list loaded modules with lm.
How can I find the memory footprint of those assemblies?
I'm analyzing a dump of a process suspected of using too much memory, and one thing I'm noticing is the number of assemblies, but not sure what's the size they occupy in memory.
Also, they don't seem to be in contiguous memory positions. Or are they if I sort lm's output some way?
Thanks!
The !address -summary gives you a good overview.
Check the Image row
0:008> !address -summary
--- Usage Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
Free 212 b13cb000 ( 2.769 Gb) 69.23%
Heap 455 25281000 ( 594.504 Mb) 47.18% 14.51%
<unknown> 861 2168d000 ( 534.551 Mb) 42.42% 13.05%
Image 662 4e8e000 ( 78.555 Mb) 6.23% 1.92%
Stack 156 3400000 ( 52.000 Mb) 4.13% 1.27%
Other 39 54000 ( 336.000 kb) 0.03% 0.01%
TEB 52 34000 ( 208.000 kb) 0.02% 0.00%
PEB 1 1000 ( 4.000 kb) 0.00% 0.00%
You can check each module's size by using lmvm module_name. There is an ImageSize output indicating the hexidecimal size of that module.
Edited: Another way is to first lm to show all modules, and then use !lmi start_address or !lmi module_name to get information about a specific module. !lmi has a Size field that indicates image size.
Note that for .NET 4 native images loaded, you have to use !lmi start_address, as module name resolution fails.
I am trying to import certain data into my SAS datset using this piece of code:
Data Names_And_More;
Infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt';
Input Name & $20.
Phone : $20.
Height & $10.
Mixed & $10.;
run;
The data in the file is as below:
Roger Cody (908)782-1234 5ft. 10in. 50 1/8
Thomas Jefferson (315)848-8484 6ft. 1in. 23 1/2
Marco Polo (800)123-4567 5Ft. 6in. 40
Brian Watson (518)355-1766 5ft. 10in 89 3/4
Michael DeMarco (445)232-2233 6ft. 76 1/3
I have been trying to learn SAS and while going through Ron Cody's book Learning SAS by example,I found to import the kind of data above, we can use 'the ampersand (&) informat modifier. The ampersand, like the colon,says to use the supplied informat, but the delimiter is now two or more blanks instead of just one.' (Ron's words, not mine). However, while importing this the result (dataset) is as follows:
Name Phone Height Mixed
Roger Cody (908)782- Thomas Jefferson Marco Polo
Also, for further details the SAS log is as follows:
419 Data Names_And_More;
420 Infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt';
421 Input Name & $20.
422 Phone : $20.
423 Height & $10.
424 Mixed & $10.
425 ;run;
NOTE:
The infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt' is:
File Name=C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt,
RECFM=V,LRECL=256
NOTE:
LOST CARD.
Name=Brian Watson (518)35 Phone=Michael Height=DeMarco (4 Mixed= ERROR=1 N=2
NOTE: 5 records were read from the infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3
Portable\Names_and_More.txt'.
The minimum record length was 37.
The maximum record length was 47.
NOTE: SAS went to a new line when INPUT statement reached past the end of a line.
NOTE: The data set WORK.NAMES_AND_MORE has 1 observations and 4 variables.
NOTE: DATA statement used (Total process time):
real time 0.17 seconds
cpu time 0.14 seconds
I am looking for some help with this one. It'd be great if someone can explain what exactly is happening, what am I doing wrong and how to correct this error.
Thanks
The answer is in the explanation in Ron Cody's book. & means you need two spaces to separate varaibles; so you need a second space after the name (and other fields with &).
Wrong:
Roger Cody (908)782-1234 5ft. 10in. 50 1/8
Right:
Roger Cody (908)782-1234 5ft. 10in. 50 1/8