[libc] implement faccessat

[michaelrj-google]

Described in POSIX: https://pubs.opengroup.org/onlinepubs/9799919799/functions/access.html

The faccessat function is a syscall wrapper that checks if a file is available.

This will be very similar to the access syscall wrapper, implemented here:

llvm-project/libc/src/unistd/linux/access.cpp

Line 24 in 2e83f10

#elif defined(SYS_faccessat)

Here's a checklist for what you'll need to do for this:

• Add the implementation of faccessat in /src/unistd
• Add tests for faccessat in /test/src/unistd
• Add faccessat to entrypoints.txt for at least x86_64 and whatever you're building on
• Add faccessat to include/unistd.yaml

(Reserved for specific assignee)

[llvmbot]

@llvm/issue-subscribers-libc

Author: Michael Jones (michaelrj-google)

Described in POSIX: https://pubs.opengroup.org/onlinepubs/9799919799/functions/access.html

The faccessat function is a syscall wrapper that checks if a file is available.

This will be very similar to the access syscall wrapper, implemented here:

llvm-project/libc/src/unistd/linux/access.cpp

Line 24 in 2e83f10

#elif defined(SYS_faccessat)

Here's a checklist for what you'll need to do for this:

• Add the implementation of faccessat in /src/unistd
• Add tests for faccessat in /test/src/unistd
• Add faccessat to entrypoints.txt for at least x86_64 and whatever you're building on
• Add faccessat to include/unistd.yaml

(Reserved for specific assignee)

[mleleszi]

Hey @michaelrj-google, I'd like to work on this!

[michaelrj-google]

completed in #161065