From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Cc: w6b7rk5yu4mt25v3 <w6b7rk5yu4mt25v3@protonmail.com>
Subject: Re: Fw: Re: Why do these mprotect always fail?
Date: Wed, 15 Feb 2023 13:13:36 +0100 [thread overview]
Message-ID: <Y+zMcAP/eIZ1DTi8@calimero.vinschen.de> (raw)
In-Reply-To: <TlepM9ESIu1ZpPCpz1vzmSoBKsKnuUABID2BREun8gb9tEPApKByf5s-_DHR9C6h48OdPFnU5uZ0Xc4JTTd-gtPH2RqhOHgOiSh-spI9K88=@protonmail.com>
On Feb 15 11:14, w6b7rk5yu4mt25v3 via Cygwin wrote:
> Corinna Vinschen wrote:
>
> > cygwin-developers is for developers woking on Cygwin itself, not for
> > developers using Cygwin to develop something else. I dropped the ML
> > from the recipient list.
> >
> > And please don't top-post. Thanks.
> >
> > On Feb 15 09:43, w6b7rk5yu4mt25v3 via Cygwin wrote:
> >
> > > Almost forgot, PAGE_SIZE is set to 4096. This is a Linux application,
> > > when I compile on Cygwin it complained that PAGE_SIZE is redefined but
> > > the compilation was success nevertheless. Only when I run the
> > > application, I always exited with "Unable to mprotect".
> >
> >
> > PAGESIZE is 64K on Cygwin. If you change that, it breaks and you can
> > keep the pieces.
> >
> > It would be nice to send a complete, self-contained STC() in plain C,
> > so reproducing your issue is simple and doesn't require to rework
> > your code to get a running, debuggable testcase.
>
> PAGE_SIZE is just a naming conflict. If you change it to something
> else, JIT_PAGE_SIZE for example, it still fails.
You're misunderstanding what PAGESIZE or PAGE_SIZE means. It's the
system page size used for mappings, and it's a fixed value defined by
the system and provided to you by the system headers and, especially,
sysconf(_SC_PAGE_SIZE).
It's *NOT* something you can just change and think the result will still
work. Especially given that mmap doesn't know that you changed a macro
in your application code...
> The problem is Cygwin
> is not fine with the particular value 4096 but the program needs the
> value to be exactly 4096.
Sorry, but that can't work. If the program actually demands it, it's
non-portable.
Corinna
next prev parent reply other threads:[~2023-02-15 12:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-15 9:38 w6b7rk5yu4mt25v3
2023-02-15 9:43 ` w6b7rk5yu4mt25v3
2023-02-15 10:32 ` Corinna Vinschen
2023-02-15 11:14 ` Fw: " w6b7rk5yu4mt25v3
2023-02-15 12:13 ` Corinna Vinschen [this message]
2023-02-15 12:40 ` w6b7rk5yu4mt25v3
2023-02-15 13:02 ` Oskar Skog
2023-02-15 15:31 ` Fw: " w6b7rk5yu4mt25v3
2023-02-15 16:33 ` Corinna Vinschen
2023-02-15 17:20 ` [EXTERNAL] " Lavrentiev, Anton (NIH/NLM/NCBI) [C]
2023-02-19 13:08 ` w6b7rk5yu4mt25v3
2023-02-19 15:40 ` Fw: " w6b7rk5yu4mt25v3
2023-02-15 13:41 ` Corinna Vinschen
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