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Get OS uptime

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Julien Delplanque

Mar 19, 2015; 5:58am

Get OS uptime

205 posts

Hi everyone,

I can't find out how to get the uptime of the OS from pharo.

I tried:

(FileLocator root / 'proc' / 'uptime') readStream contents.

and

(FileSystem disk root / 'proc' / 'uptime') readStream contents.

but all what I get is an empty string ''.

I don't know if there are messages in some specific classes to do this
(in OSProcess for example?).

Thanks in advance.

Julien

EstebanLM

Mar 19, 2015; 10:01am

Re: Get OS uptime

6187 posts

'/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].

is better way.

but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)

you should use OSProcess instead (installable from Configurations Browser)

(PipeableOSProcess command: 'uptime') upToEndOfFile.

Esteban

> On 19 Mar 2015, at 07:07, Julien Delplanque <[hidden email]> wrote:
>
> Hi everyone,
>
> I can't find out how to get the uptime of the OS from pharo.
>
> I tried:
>
> (FileLocator root / 'proc' / 'uptime') readStream contents.
>
> and
>
> (FileSystem disk root / 'proc' / 'uptime') readStream contents.
>
> but all what I get is an empty string ''.
>
> I don't know if there are messages in some specific classes to do this
> (in OSProcess for example?).
>
> Thanks in advance.
>
> Julien
>

... [show rest of quote]

Julien Delplanque

Mar 19, 2015; 10:25am

Re: Get OS uptime

205 posts

On 19/03/15 11:10, Esteban Lorenzano wrote:

> '/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].
>
> is better way.
>
> but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)
>
> you should use OSProcess instead (installable from Configurations Browser)
>
> (PipeableOSProcess command: 'uptime') upToEndOfFile.
>
> Esteban

Oh, I didn't know '/proc' doesn't contains real files. I tought there
were files in this directory since you do 'cat /proc/uptime' in a shell.

EstebanLM

Mar 19, 2015; 10:41am

Re: Get OS uptime

6187 posts

> On 19 Mar 2015, at 11:35, Julien Delplanque <[hidden email]> wrote:
>
>
> On 19/03/15 11:10, Esteban Lorenzano wrote:
>> '/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].
>>
>> is better way.
>>
>> but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)
>>
>> you should use OSProcess instead (installable from Configurations Browser)
>>
>> (PipeableOSProcess command: 'uptime') upToEndOfFile.
>>
>> Esteban
> Oh, I didn't know '/proc' doesn't contains real files. I tought there
> were files in this directory since you do 'cat /proc/uptime' in a shell.

... [show rest of quote]

that’s the O.S. cheating you :)

Esteban

Julien Delplanque

Mar 19, 2015; 11:01am

Re: Get OS uptime

205 posts

On 19/03/15 11:51, Esteban Lorenzano wrote:

>> On 19 Mar 2015, at 11:35, Julien Delplanque <[hidden email]> wrote:
>>
>>
>> On 19/03/15 11:10, Esteban Lorenzano wrote:
>>> '/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].
>>>
>>> is better way.
>>>
>>> but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)
>>>
>>> you should use OSProcess instead (installable from Configurations Browser)
>>>
>>> (PipeableOSProcess command: 'uptime') upToEndOfFile.
>>>
>>> Esteban
>> Oh, I didn't know '/proc' doesn't contains real files. I tought there
>> were files in this directory since you do 'cat /proc/uptime' in a shell.
> that’s the O.S. cheating you :)
>
> Esteban
>

... [show rest of quote]

Haha ok, nice to know :)

Julien

NorbertHartl

Mar 19, 2015; 11:58am

Re: Get OS uptime

3479 posts

In reply to this post by EstebanLM

> Am 19.03.2015 um 11:51 schrieb Esteban Lorenzano <[hidden email]>:
>
>
>> On 19 Mar 2015, at 11:35, Julien Delplanque <[hidden email]> wrote:
>>
>>
>> On 19/03/15 11:10, Esteban Lorenzano wrote:
>>> '/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].
>>>
>>> is better way.
>>>
>>> but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)
>>>
>>> you should use OSProcess instead (installable from Configurations Browser)
>>>
>>> (PipeableOSProcess command: 'uptime') upToEndOfFile.
>>>
>>> Esteban
>> Oh, I didn't know '/proc' doesn't contains real files. I tought there
>> were files in this directory since you do 'cat /proc/uptime' in a shell.
>
> that’s the O.S. cheating you :)
>

... [show rest of quote]

Can you elaborate on that statement. What is a "real" file and why are the files in /proc not real?

Norbert

EstebanLM

Mar 19, 2015; 12:17pm

Re: Get OS uptime

6187 posts

On 19 Mar 2015, at 13:08, Norbert Hartl <[hidden email]> wrote:

Am 19.03.2015 um 11:51 schrieb Esteban Lorenzano <[hidden email]>:

On 19 Mar 2015, at 11:35, Julien Delplanque <[hidden email]> wrote:

On 19/03/15 11:10, Esteban Lorenzano wrote:
'/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].

is better way.

but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)

you should use OSProcess instead (installable from Configurations Browser)

(PipeableOSProcess command: 'uptime') upToEndOfFile.

Esteban
Oh, I didn't know '/proc' doesn't contains real files. I tought there
were files in this directory since you do 'cat /proc/uptime' in a shell.
... [show rest of quote]

that’s the O.S. cheating you :)

... [show rest of quote]
Can you elaborate on that statement. What is a "real" file and why are the files in /proc not real?

... [show rest of quote]

better: http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/proc.html

"proc is very special in that it is also a virtual filesystem. It's sometimes referred to as a process information pseudo-file system. It doesn't contain 'real' files but runtime system information (e.g. system memory, devices mounted, hardware configuration, etc). For this reason it can be regarded as a control and information centre for the kernel. In fact, quite a lot of system utilities are simply calls to files in this directory.”

last part of that sentence is what made me think that *maybe* FilePlugin should thread them as regular files… :)

Esteban

Norbert

Damien Pollet-2

Mar 19, 2015; 12:17pm

Re: Get OS uptime

103 posts

In reply to this post by NorbertHartl

/proc are entries in the filesystem, as such I don't see why the file plugin would fail to access them… unless you cannot use block devices and such like any other file? In Unix, everything is a file, except those that have to be special-cased apart?

On 19 March 2015 at 13:08, Norbert Hartl <[hidden email]> wrote:

> Am 19.03.2015 um 11:51 schrieb Esteban Lorenzano <[hidden email]>:

>
>
>> On 19 Mar 2015, at 11:35, Julien Delplanque <[hidden email]> wrote:
>>
>>
>> On 19/03/15 11:10, Esteban Lorenzano wrote:
>>> '/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].
>>>
>>> is better way.
>>>
>>> but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)
>>>
>>> you should use OSProcess instead (installable from Configurations Browser)
>>>
>>> (PipeableOSProcess command: 'uptime') upToEndOfFile.
>>>
>>> Esteban
>> Oh, I didn't know '/proc' doesn't contains real files. I tought there
>> were files in this directory since you do 'cat /proc/uptime' in a shell.
>
> that’s the O.S. cheating you :)
>

Can you elaborate on that statement. What is a "real" file and why are the files in /proc not real?

Norbert

... [show rest of quote]

EstebanLM

Mar 19, 2015; 12:18pm

Re: Get OS uptime

6187 posts

In reply to this post by EstebanLM

On 19 Mar 2015, at 13:26, Esteban Lorenzano <[hidden email]> wrote:

On 19 Mar 2015, at 13:08, Norbert Hartl <[hidden email]> wrote:

Am 19.03.2015 um 11:51 schrieb Esteban Lorenzano <[hidden email]>:

On 19 Mar 2015, at 11:35, Julien Delplanque <[hidden email]> wrote:

On 19/03/15 11:10, Esteban Lorenzano wrote:
'/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].

is better way.

but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)

you should use OSProcess instead (installable from Configurations Browser)

(PipeableOSProcess command: 'uptime') upToEndOfFile.

Esteban
Oh, I didn't know '/proc' doesn't contains real files. I tought there
were files in this directory since you do 'cat /proc/uptime' in a shell.

that’s the O.S. cheating you :)

... [show rest of quote]
Can you elaborate on that statement. What is a "real" file and why are the files in /proc not real?
... [show rest of quote]

better: http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/proc.html

"proc is very special in that it is also a virtual filesystem. It's sometimes referred to as a process information pseudo-file system. It doesn't contain 'real' files but runtime system information (e.g. system memory, devices mounted, hardware configuration, etc). For this reason it can be regarded as a control and information centre for the kernel. In fact, quite a lot of system utilities are simply calls to files in this directory.”

last part of that sentence is what made me think that *maybe* FilePlugin should thread them as regular files… :)

... [show rest of quote]

s/thread/treat

Esteban

Norbert

NorbertHartl

Mar 19, 2015; 12:59pm

Re: Get OS uptime

3479 posts

In reply to this post by EstebanLM

Am 19.03.2015 um 13:26 schrieb Esteban Lorenzano <[hidden email]>:

On 19 Mar 2015, at 13:08, Norbert Hartl <[hidden email]> wrote:

Am 19.03.2015 um 11:51 schrieb Esteban Lorenzano <[hidden email]>:

On 19 Mar 2015, at 11:35, Julien Delplanque <[hidden email]> wrote:

On 19/03/15 11:10, Esteban Lorenzano wrote:
'/proc/uptime' asFileReference readStreamDo: [ :stream | stream contents ].

is better way.

but you will still get an empty string because actually ‘/proc’ does not contains real files… so the file plugin does not applies there (and is another debate if it should…)

you should use OSProcess instead (installable from Configurations Browser)

(PipeableOSProcess command: 'uptime') upToEndOfFile.

Esteban
Oh, I didn't know '/proc' doesn't contains real files. I tought there
were files in this directory since you do 'cat /proc/uptime' in a shell.
... [show rest of quote]

that’s the O.S. cheating you :)

... [show rest of quote]
Can you elaborate on that statement. What is a "real" file and why are the files in /proc not real?
... [show rest of quote]

better: http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/proc.html

"proc is very special in that it is also a virtual filesystem. It's sometimes referred to as a process information pseudo-file system. It doesn't contain 'real' files but runtime system information (e.g. system memory, devices mounted, hardware configuration, etc). For this reason it can be regarded as a control and information centre for the kernel. In fact, quite a lot of system utilities are simply calls to files in this directory.”

last part of that sentence is what made me think that *maybe* FilePlugin should thread them as regular files… :)

... [show rest of quote]

That's my point. Or better I like to know how the plugin can distinguish them. Usually there shouldn't be a difference. I know the /proc filesystem. It is what unix is all about. Make every information available as file. You say it is a virtual filesystem? Yes, but there are only virtual filesystems in linux. Below is always a device driver accessing disks, cdroms, etc. Memory or the kernel does not make a difference. They are all the same and they should according to unix. So I still not understand the problem.

Norbert

Martin Bähr

Mar 19, 2015; 1:39pm

Re: Get OS uptime

169 posts

Excerpts from Norbert Hartl's message of 2015-03-19 14:09:28 +0100:
> That's my point. Or better I like to know how the plugin can distinguish
> them. Usually there shouldn't be a difference. I know the /proc filesystem.
> It is what unix is all about. Make every information available as file. You
> say it is a virtual filesystem? Yes, but there are only virtual filesystems
> in linux. Below is always a device driver accessing disks, cdroms, etc.
> Memory or the kernel does not make a difference. They are all the same and
> they should according to unix. So I still not understand the problem.

files in /proc are not seekable.
that or something related may be the problem.

compare this strace:

/proc/uptime:
lstat64("/proc/uptime", {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
open("/proc/uptime", O_RDONLY) = 8
fstat64(8, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xfffffffff722e000
fstat64(8, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
_llseek(8, 0, [0], SEEK_SET) = 0
_llseek(8, 0, [0], SEEK_SET) = 0
_llseek(8, 0, [0], SEEK_SET) = 0
_llseek(8, 0, [0], SEEK_SET) = 0
close(8) = 0

/etc/profile:
lstat64("/etc/profile", {st_mode=S_IFREG|0644, st_size=1750, ...}) = 0
open("/etc/profile", O_RDONLY) = 8
fstat64(8, {st_mode=S_IFREG|0644, st_size=1750, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xfffffffff722e000
fstat64(8, {st_mode=S_IFREG|0644, st_size=1750, ...}) = 0
_llseek(8, 0, [0], SEEK_SET) = 0
read(8, "# /etc/profile\n\n# System wide en"..., 1750) = 1750
_llseek(8, 1750, [1750], SEEK_SET) = 0
_llseek(8, 1750, [1750], SEEK_SET) = 0
read(8, "", 4096) = 0
_llseek(8, 0, [0], SEEK_SET) = 0
close(8) = 0

/proc/uptime comes with a filesize of 0, and this, pharo tries to read 0 bytes from it.
or rather, since there is no read() call, it concludes that there is nothing to read.

greetings, martin.

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Michal Balda

Mar 19, 2015; 2:09pm

Re: Get OS uptime

10 posts

In reply to this post by Julien Delplanque

Hi,
your solution does not work because files in /proc are virtual and have
no size (their size will be reported as 0).
FileStream>>contents sends #size to determine the length and that will
return 0 for all files in /proc.

So the solution is to use something that does not use #size, like:

(FileLocator root / 'proc' / 'uptime') readStream upToEnd

Michal

On 19.3.2015 07:07, Julien Delplanque wrote:

> Hi everyone,
>
> I can't find out how to get the uptime of the OS from pharo.
>
> I tried:
>
> (FileLocator root / 'proc' / 'uptime') readStream contents.
>
> and
>
> (FileSystem disk root / 'proc' / 'uptime') readStream contents.
>
> but all what I get is an empty string ''.
>
> I don't know if there are messages in some specific classes to do this
> (in OSProcess for example?).
>
> Thanks in advance.
>
> Julien
>

... [show rest of quote]