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Closed
Tracked by #51211
ycsin opened this issue Jul 3, 2023 · 4 comments · Fixed by #73799
Closed
Tracked by #51211

posix: implement mmap() #59950

ycsin opened this issue Jul 3, 2023 · 4 comments · Fixed by #73799
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@cfriedt
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area: POSIX POSIX API Library Enhancement Changes/Updates/Additions to existing features Good first issue Good for a first time contributor to take

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@ycsin
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ycsin commented Jul 3, 2023

There are currently 20 missing POSIX functions with trivial implementations, mmap() is one of them.

mmap - map pages of memory

The mmap() function shall establish a mapping between an address space of a process and a memory object.
...

See https://pubs.opengroup.org/onlinepubs/9699919799/functions/mmap.html

See RFC #51211 for more info.
@ycsin ycsin added Feature Request A request for a new feature Good first issue Good for a first time contributor to take area: POSIX POSIX API Library labels Jul 3, 2023
@ycsin ycsin mentioned this issue Jul 3, 2023
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@ycsin ycsin moved this to LTS3 Goals in Release Plan Jul 3, 2023
@ycsin ycsin added this to the v3.5.0 milestone Jul 3, 2023
@cfriedt cfriedt assigned cfriedt and unassigned cfriedt Jul 4, 2023
@cfriedt cfriedt removed the status in Release Plan Sep 12, 2023
@nashif nashif removed this from Release Plan Sep 13, 2023
@cfriedt cfriedt removed this from the v3.5.0 milestone Oct 13, 2023
@KaiserS0ze
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Hi @ycsin I am a first-time contributor. Can I take a crack at this?

@ycsin
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ycsin commented Nov 20, 2023

Hi @ycsin I am a first-time contributor. Can I take a crack at this?

Hi, please feel free to submit PR for anything

@cfriedt
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cfriedt commented Nov 20, 2023 •
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mmap() can actually get very complicated. It certainly isn't trivial.

We can definitely start out simple though.

Where should we get the file descriptor? How do we differentiate between real and special files? Some of these things might be tricky and there could be dependencies on other POSIX API calls (e.g. stat?)

  1. memory (identity / physical)
  2. memory (virtual)
  3. Device memory (physical)
  4. Regular File from file system, read-only (physical)
    ..

@KaiserS0ze
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Thanks. Yes, I think there are a lot of edge cases. I will start off with a simple implementation.

@nashif nashif added Enhancement Changes/Updates/Additions to existing features and removed Feature Request A request for a new feature labels Jan 19, 2024
@cfriedt cfriedt mentioned this issue Jun 11, 2024
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area: POSIX POSIX API Library Enhancement Changes/Updates/Additions to existing features Good first issue Good for a first time contributor to take
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posix: add support for mmap, memlock, shared memory, and mprotect cfriedt/zephyr
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@nashif @cfriedt @ycsin @KaiserS0ze