On 11.10.18 23:35, Bob Proulx wrote:
> The smallest of details can break the largest of programs. :-)
>
> Good to hear you have things resolved and now working for you!
Thanks all for your insights and help!
Cheers, Dirk
Dirk Wetter wrote:
> PS + @Bob: fd 5 is not a tty in the program -- but interactively in
> this PoC you want to make sure it is not taken yet.
Understood. I originally mentioned the isatty() thing because that is
how libc decides to line buffer or not. But Chet has confirmed that
bash's internal
On 10/11/18 12:53 PM, Dirk Wetter wrote:
> This all -- including cat -- sounded reasonable. But it seems using sockets
> the internal printf
> as opposed to the one from coreutils is still causing fragmentation other
> than expected with
> strace PoC:
Bash line-buffers stdout, so newlines caus
On 11.10.18 18:53, Dirk Wetter wrote:
> bash 0$ exec 5<>/dev/tcp/81.169.199.25/443
> bash 0$ printf
> '\x16\x03\x01\x02\x00\x01\x00\x01\xfc\x03\x03\x54\x51\x1e\x7a\xde\xad\xbe\xef\x31\x33\x07\x00\x00\x00\x00\x00\xcf\xbd\x39\x04\xcc\x16\x0b\x85\x03\x90\x9f\x77\x04\x33\xd4\xde\x20\x44\xb8\x92\x56\
On 23.09.18 20:29, Bob Proulx wrote:
> Robert Elz wrote:
> $ { command printf "one\n"; sleep 1; command printf "two\n" ;} | strace -v
> -o /tmp/dd.strace.out -e write,read dd status=none ibs=1M obs=1M ; head
> /tmp/*.strace.out
> one
> two
> ...
> read(0, "one\n", 1048576)
On 9/26/18 2:17 AM, Dirk Wetter wrote:
>> then what happens if "$data" is
>> a paragraph of text with embedded newlines. In that case,
>> it sounds like bash might break apart the single printf
>> output into smaller packets rather than transmitting the
>> entirety of "$data" in 1 write (presumin
On 9/25/18 2:15 PM, L A Walsh wrote:
>
>
> On 9/24/2018 6:05 AM, Greg Wooledge wrote:
>> On Sat, Sep 22, 2018 at 11:50:17AM +0200, dirk+b...@testssl.sh wrote:
>>
>>> On 9/22/18 7:30 AM, Bob Proulx wrote:
>>>
dirk+b...@testssl.sh wrote:
> printf -- "$data" >&5 2>/dev/n
> On 9/25/18 9:04 AM, dirk+b...@testssl.sh wrote:
> > env or exec: never thought about it (thanks!) but as both are external
> > commands, that would mean upon every call one additional external program.
> > (yes, I know that there is such thing as a fs buffer). Subshells also costs
> > resources.
On 9/25/18 3:46 PM, Chet Ramey wrote:
> On 9/25/18 9:04 AM, dirk+b...@testssl.sh wrote:
>
>> FYI: I ended up checking with type before whether an external printf
>> exists and set a variable for this and then just call this variable.
>>
>> env or exec: never thought about it (thanks!) but as bo
On 9/25/18 8:25 AM, Greg Wooledge wrote:
> On Tue, Sep 25, 2018 at 05:15:02AM -0700, L A Walsh wrote:
>> On 9/24/2018 6:05 AM, Greg Wooledge wrote:
>>> On Sat, Sep 22, 2018 at 11:50:17AM +0200, dirk+b...@testssl.sh wrote:
On 9/22/18 7:30 AM, Bob Proulx wrote:
> dirk+b...@testssl.sh wrote:
On 9/25/18 9:04 AM, dirk+b...@testssl.sh wrote:
> FYI: I ended up checking with type before whether an external printf
> exists and set a variable for this and then just call this variable.
>
> env or exec: never thought about it (thanks!) but as both are external
> commands, that would mean upon
On 9/23/18 8:26 PM, Chet Ramey wrote:
> On 9/22/18 4:22 PM, Bob Proulx wrote:
>
>> Note that I *did* provide you with a way to do what you wanted to do. :-)
>>
>> It was also noted in another message that the external standalone
>> printf command line utility did buffer as you desired. That see
On Tue, Sep 25, 2018 at 05:15:02AM -0700, L A Walsh wrote:
> On 9/24/2018 6:05 AM, Greg Wooledge wrote:
> > On Sat, Sep 22, 2018 at 11:50:17AM +0200, dirk+b...@testssl.sh wrote:
> > > On 9/22/18 7:30 AM, Bob Proulx wrote:
> > > > dirk+b...@testssl.sh wrote:
> > > > > printf -- "$data" >&5 2>/dev/nu
On 9/24/2018 6:05 AM, Greg Wooledge wrote:
On Sat, Sep 22, 2018 at 11:50:17AM +0200, dirk+b...@testssl.sh wrote:
On 9/22/18 7:30 AM, Bob Proulx wrote:
dirk+b...@testssl.sh wrote:
printf -- "$data" >&5 2>/dev/null
What happens if $data contains % format strings? Wha
On Sat, Sep 22, 2018 at 11:50:17AM +0200, dirk+b...@testssl.sh wrote:
> On 9/22/18 7:30 AM, Bob Proulx wrote:
> > dirk+b...@testssl.sh wrote:
> >> printf -- "$data" >&5 2>/dev/null
> >
> > What happens if $data contains % format strings? What happens if the
> > format contains a sequence such as
On 9/23/18 2:46 PM, Bob Proulx wrote:
> Chet Ramey wrote:
>> It's that bash sets stdout and stderr to be line-buffered, not anything
>> printf-specific.
>
> Shouldn't bash set stdout buffering based upon the output descriptor
> being a tty or not the same as other libc stdio behavior?
It's been s
Chet Ramey wrote:
> It's that bash sets stdout and stderr to be line-buffered, not anything
> printf-specific.
Shouldn't bash set stdout buffering based upon the output descriptor
being a tty or not the same as other libc stdio behavior?
Bob
Chet Ramey wrote:
> Bob Proulx wrote:
> > It was also noted in another message that the external standalone
> > printf command line utility did buffer as you desired. That seems
> > another very good solution too. Simply use "command printf ..." to
> > force using the external version.
>
> This
Robert Elz wrote:
> Bob Proulx wrote:
> | Using the same buffer size
> | for input and output is usually most efficient.
>
> Yes, but as the objective seemed to be to make big packets, that is probably
> not as important.
The original complaint concerned flushing a data blob content upon
ever
On 9/22/18 4:22 PM, Bob Proulx wrote:
> Note that I *did* provide you with a way to do what you wanted to do. :-)
>
> It was also noted in another message that the external standalone
> printf command line utility did buffer as you desired. That seems
> another very good solution too. Simply us
On 9/22/18 6:49 AM, dirk+b...@testssl.sh wrote:
>
>
> On 9/22/18 12:38 PM, Ilkka Virta wrote:
>> On 22.9. 02:34, Chet Ramey wrote:
>>> Newline? It's probably that stdout is line-buffered and the newline causes
>>> a flush, which results in a write(2).
>>
>> Mostly out of curiosity, what kind of b
Date:Sat, 22 Sep 2018 23:51:08 -0600
From:Bob Proulx
Message-ID: <20180922231240358868...@bob.proulx.com>
| Using the same buffer size
| for input and output is usually most efficient.
Yes, but as the objective seemed to be to make big packets, that is probably
n
Robert Elz wrote:
> ps: f there was actually a desire to use dd to do re-buffering, the
> correct usage is not to use "bs=" (which simply does read write with
> a buffer that size) but "obs=" which reads (using ibs if needed, which it
> would not be here), copies to an output buffer and writes only
Date:Sat, 22 Sep 2018 14:22:19 -0600
From:Bob Proulx
Message-ID: <20180922111950901701...@bob.proulx.com>
| Primarily a shell script is a command and control program. It is very
| good for that purpose. It is typically used for that purpose. That
| is the ma
I see that you have subscribed now. Awesome! If you and others would
be so kind as to list-reply instead of CC'ing me directly that would
be great. I read the replies on the mailing list.
dirk+b...@testssl.sh wrote:
> Bob Proulx wrote:
> > You are doing something that is quite unusual. You are
On 9/22/18 6:38 AM, Ilkka Virta wrote:
> On 22.9. 02:34, Chet Ramey wrote:
>> Newline? It's probably that stdout is line-buffered and the newline causes
>> a flush, which results in a write(2).
>
> Mostly out of curiosity, what kind of buffering logic does Bash (or the
> builtin printf in particul
On 9/22/18 4:21 AM, dirk+b...@testssl.sh wrote:
>
>
> On 9/22/18 1:34 AM, Chet Ramey wrote:
>> On 9/21/18 4:13 PM, dirk+b...@testssl.sh wrote:
>>>
>>> Hello there,
>>>
>>> we discovered a strange phenomenon in the project testssl.sh:
>>>
>>> After opening a TCP socket with a fd (here: 5), when wr
On 9/22/18 12:30 PM, Ilkka Virta wrote:
> The coreutils printf seems to output 'foo\nbar\n' as a single write, though
> (unless
> it goes to the terminal, so the usual stdio buffering), so you might be able
> to use
> that.
thx. Might be not that portable but we'll see.
> In any case, if a
On 9/22/18 12:38 PM, Ilkka Virta wrote:
> On 22.9. 02:34, Chet Ramey wrote:
>> Newline? It's probably that stdout is line-buffered and the newline causes
>> a flush, which results in a write(2).
>
> Mostly out of curiosity, what kind of buffering logic does Bash (or the
> builtin
> printf in p
On 22.9. 02:34, Chet Ramey wrote:
Newline? It's probably that stdout is line-buffered and the newline causes
a flush, which results in a write(2).
Mostly out of curiosity, what kind of buffering logic does Bash (or the
builtin printf in particular) use? It doesn't seem to be the usual stdio
l
On 22.9. 12:50, dirk+b...@testssl.sh wrote:
cat has a problem with binary chars, right? And: see below.
No, it just loops with read() and write(), it shouldn't touch any of the
bytes (except for cat -A and such). But it probably doesn't help in
coalescing the write blocks, it's likely to just
On 9/22/18 7:30 AM, Bob Proulx wrote:
> dirk+b...@testssl.sh wrote:
>> we discovered a strange phenomenon in the project testssl.sh:
>
> You are doing something that is quite unusual. You are using a shell
> script direction on a TCP socket. That isn't very common.
Do you think there shoul
On 9/22/18 1:34 AM, Chet Ramey wrote:
> On 9/21/18 4:13 PM, dirk+b...@testssl.sh wrote:
>>
>> Hello there,
>>
>> we discovered a strange phenomenon in the project testssl.sh:
>>
>> After opening a TCP socket with a fd (here: 5), when writing to it,
>> it seems that
>>
>> printf -- "$data" >&5 2>
dirk+b...@testssl.sh wrote:
> we discovered a strange phenomenon in the project testssl.sh:
You are doing something that is quite unusual. You are using a shell
script direction on a TCP socket. That isn't very common. More
typically one would use a C program instead. So it isn't surprising
th
On 9/21/18 4:13 PM, dirk+b...@testssl.sh wrote:
>
> Hello there,
>
> we discovered a strange phenomenon in the project testssl.sh:
>
> After opening a TCP socket with a fd (here: 5), when writing to it,
> it seems that
>
> printf -- "$data" >&5 2>/dev/null
>
> does not do what it is intended.
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