Interesting. It seems like `os.access(path, os.W_OK)` must be returning
`False` in our python code for `upstream/emscripten/cache`.
Are you able to touch a new file in `upstream/emscripten/cache`?
What does python show when you run: python3 -c "import os;
print(os.access('upstream/emscripten/cache', os.W_OK))"
On Thu, Oct 31, 2024 at 7:56 AM John Dallman <[email protected]> wrote:
> > Can you try running `emcc` with `EMCC_DEBUG=1` as well as `EMCC_CACHE`
> set?
>
> Done.
>
> > Do you see the ` 'Using home-directory for emscripten cache due to
> read-only root` message?
>
> Yes, I do. I have:
>
> $ touch $EMCC_CACHE/test.jgd
> $ ls -l $EMCC_CACHE
> total 0
> -rw-rw-r-- 1 jgd UK-Parasolid-GG 0 Oct 31 14:42 test.jgd
> $ ls -ld $EMCC_CACHE
> drwxrwxr-x 2 kerman UK-Parasolid-GG 4096 Oct 31 14:42
> /local/kernel_webasm/tools/emcache/
> $ python3 --version
> Python 3.6.8
>
> > Where is your emscripten config coming from? Are you using `source
> emsdk_env.sh`?
>
> Yes, I'm sourcing that script. I have not altered any config files.
>
> > Making `emsdk/upstream/emscripten/cache` group writable is the correct
> solution, there
> > should be no need to serate of alternate cache directories in this case
> I think.
>
> Checking that:
>
> $ whoami
> kerman
> $ pwd
> /local/kernel_webasm/tools/emsdk
> $ ls -ld upstream/emscripten/cache
> drwxrwxr-x 4 kerman UK-Parasolid-GG 4096 Oct 24 23:29
> upstream/emscripten/cache
> $ ls -l upstream/emscripten/cache
> total 12
> drwxr-xr-x 2 kerman UK-Parasolid-GG 4096 Oct 24 23:29 build
> -rwxr-xr-x 1 kerman UK-Parasolid-GG 0 Oct 24 23:29 cache.lock
> drwxr-xr-x 5 kerman UK-Parasolid-GG 4096 Oct 24 23:18 sysroot
> -rw-r--r-- 1 kerman UK-Parasolid-GG 1 Oct 24 23:18 sysroot_install.stamp
>
> Those files were extracted with those timestamps: Oct 24 is well before I
> installed this Emscripten, and I don't work that late at night. Is the
> presence of that cache.lock file the problem?
>
> Thanks,
>
> John
>
>
> On Wed, Oct 30, 2024 at 6:33 PM 'Sam Clegg' via emscripten-discuss <
> [email protected]> wrote:
>
>>
>>
>> On Wed, Oct 30, 2024 at 5:46 AM John Dallman <[email protected]>
>> wrote:
>>
>>> This doesn't seem to be working. I'm using two accounts: "kerman" is my
>>> system management account, which can sudo, and "jgd" is my personal
>>> account. Both are members of the same primary group.
>>>
>>> I installed 3.1.70, the latest as of today, into
>>> /local/kernel_webasm/tools, and made emsdk/upstream/emscripten/cache
>>> group-writable. I then did a compile as jgd and found
>>> ~jgd/.emscripten_cache was populated and used. I removed that and thought
>>> again.
>>>
>>> I tried making the emsdk directory group-writable, and tried again.
>>> ~jgd/.emscripten_cache was populated and used. I removed it again.
>>>
>>> I created a cache directory, /local/kernel_webasm/tools/emcache/, made
>>> sure it was group-writable, and in my jgd session, did:
>>>
>>> EMCC_CACHE=/local/kernel_webasm/tools/emcache
>>> export EMCC_CACHE
>>>
>>> I tried compiling again, and once again, ~jgd/.emscripten_cache was
>>> populated and used.
>>>
>>
>> Something strange must be going on here. Can you try running `emcc`
>> with `EMCC_DEBUG=1` as well as `EMCC_CACHE` set? Do you see the ` 'Using
>> home-directory for emscripten cache due to read-only root` message?
>>
>> The `CACHE = os.path.expanduser(os.path.join('~', '.emscripten_cache'))`
>> should not even execute when you have an explicit cache configured.
>>
>> Where is your emscripten config coming from? Are you using `source
>> emsdk_env.sh`?
>>
>> Making `emsdk/upstream/emscripten/cache` group writable is the correct
>> solution, there should be no need to serate of alternate cache directories
>> in this case I think.
>>
>> cheers,
>> sam
>>
>> P.S. I am about to land a change that completely removes the fallback to
>> `$HOME/.emscripten_cache`:
>> https://github.com/emscripten-core/emscripten/pull/22801
>>
>>
>>
>>> I'm running Rocky Linux 8.10. I really do want to have many accounts
>>> capable of using the same Emscripten installation, because putting it on a
>>> network drive makes standardizing development tools very much easier.
>>>
>>> Thanks,
>>>
>>> John
>>>
>>> On Tue, Oct 29, 2024 at 9:28 PM 'Sam Clegg' via emscripten-discuss <
>>> [email protected]> wrote:
>>>
>>>> The emscripten cache actually defaults to living inside of the
>>>> emscripten directory. The line where this occurs is `CACHE =
>>>> path_from_root('cache')`. Then `os.path.expanduser(os.path.join('~',
>>>> '.emscripten_cache'))` location is only used when the emscripten directory
>>>> is read only.
>>>>
>>>> When using emsdk the cache location should always be
>>>> `emsdk/upstream/emscripten/cache`. emsdk also shipped with a
>>>> pre-populated cache so most system libraries are already built there.
>>>>
>>>> For those who want to use a different cache location you can use the
>>>> `EMCC_CACHE` environment variable or the `CACHE` key in your emscripten
>>>> config file (both of these override the default). However, it doesn't
>>>> sounds like you need to do either of those things and the default location
>>>> inside the emsdk tree should work for you. Side note: emcc will also
>>>> using the $HOME location if the in-tree location is not writable. You can
>>>> set `EMCC_FROZEN_CACHE` if you want to accept this read-only location
>>>> (obviously new libraries cannot be placed there in that case though). See
>>>> https://github.com/emscripten-core/emscripten/blob/31f9fb3c71b1aacf5edf65e35515d41b59c10391/tools/config.py#L82-L92
>>>> .
>>>>
>>>> cheers,
>>>> sam
>>>>
>>>> On Mon, Oct 28, 2024 at 10:25 AM John Dallman <[email protected]>
>>>> wrote:
>>>>
>>>>> Greetings, all!
>>>>>
>>>>> I have a somewhat unusual first project with Emscripten. I need to get
>>>>> a domain-specific C-like language generating WebAssembly. This is not too
>>>>> bad, because the DSL compiles into C code, which I then feed to the C
>>>>> compiler for the relevant platform. At this level, WebAssembly is "just
>>>>> another platform" but as always, the details are more complicated.
>>>>>
>>>>> I need to provide declarations for the platform's C run-time library
>>>>> functions, types, constants, and so on to the DSL. This is a fairly
>>>>> routine
>>>>> task, given the platform's C headers, but there are a few things about the
>>>>> Emscripten headers that are puzzling me.
>>>>>
>>>>> To forestall the obvious question, no, I can't just use the provided
>>>>> headers. The DSL is C-like, but has some syntax differences. Unlike C++,
>>>>> many C programs are not valid programs in the DSL, which gives much more
>>>>> freedom in the language design. It's a separate development that split
>>>>> from
>>>>> normal C in the mid-eighties and is still very much worth using for its
>>>>> specialised role. Yes, new hires have to learn it, which takes about two
>>>>> days for someone who knows C or C++. Learning about the specialised
>>>>> application area it is used for takes much longer.
>>>>>
>>>>> I'm running Emscripten on Linux. I started by looking at Emscripten
>>>>> 3.1.41, since that's the version used by a couple of other product teams
>>>>> that work on my site. That is fairly simple when I run a few emcc compiles
>>>>> with -H to get a report of what files are referenced. The top-level
>>>>> headers
>>>>> come from emsdk/upstream/emscripten/cache/sysroot/include. A few
>>>>> Clang-associated ones come from emsdk/upstream/lib/clang/17/include.
>>>>> That's
>>>>> all fine with me.
>>>>>
>>>>> Then I decided to check the latest emsdk, and found that with 3.1.69,
>>>>> the headers come from a different place. It builds a cache of the headers
>>>>> and other files it uses under ~/.emscripten_cache. The problems with that
>>>>> are:
>>>>>
>>>>> Storage: It will take 36MB in the user directory of everyone who ever
>>>>> compiles with Emscripten. We keep all our user directories on a server
>>>>> disk, because that's enormously convenient in many ways. But we really
>>>>> don't want to burn space with duplicates of that cache.
>>>>>
>>>>> Version lock: We need to be able to have several Emscripten versions
>>>>> in use simultaneously, by the same account, without conflicts. Our reason
>>>>> for this is that we plan to release products on WebAssembly, and from time
>>>>> to time, update the version of Emscripten we use, to get access to new C
>>>>> and C++ standards, compiler bug fixes, and so on. But we will not update
>>>>> the tools used to build a product version that's been released and is
>>>>> under
>>>>> maintenance, because we'd have to re-do a lot of the QA that we do at a
>>>>> release. So the service accounts that run our builds can't have caches of
>>>>> version-specific headers in their user directories.
>>>>>
>>>>> I need a way to tell Emscripten to put that cache somewhere else. I
>>>>> did some grep'ing of the Emscripten scripts, and found this line, in both
>>>>> 3.1.41 and 3.1.69:
>>>>>
>>>>> upstream/emscripten/tools/config.py: CACHE =
>>>>> os.path.expanduser(os.path.join('~', '.emscripten_cache'))
>>>>>
>>>>> I have not yet attempted to read the Python code and learn how it all
>>>>> works, because that could take ages; I don't know Python well at all and
>>>>> am
>>>>> not keen on it. I'm a naturally low-level programmer, much happier with
>>>>> assembly code than object orientation
>>>>>
>>>>> Is there an environment variable I can use to relocate that cache?
>>>>>
>>>>> Thanks very much,
>>>>>
>>>>> John
>>>>>
>>>>> --
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>>>>>
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