Re: POSIX XXXat() methods

On 2020-07-20 16:33, Joel Sherrill wrote:
> Eshan has been looking for generic implementations of the 15 POSIX methods
> like openat(), mkdirat(), etc. He has searched the normal places I know of
> and hasn't found implementations of most of them that don't just call a
> dedicated system call. Here is his analysis.
> 
> https://docs.google.com/spreadsheets/d/1nEniQOs9TxDy5fb7P0_XFg7VknQDldG1BDFWSoqdKg0/edit?usp=sharing
> 
> It appears that many could be implemented generically but with possible
> overhead of saving current working directory, changing, returning, etc. and
> likely race conditions.
> 
> Does anyone have any ideas on where to get generic implementations to port?
> Or implementation strategies to write OS agnostic versions?

Would those used by Cygwin in the other half of your favourite repo qualify,
although AFAIK they are under LGPL3+ with a section 4 Combined Works Linking
Exception and section 5 Combined Libraries allows choice of terms with conditions:

https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=winsup/CYGWIN_LICENSE
https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=winsup/COPYING.LIB

Add openat, faccessat, fchmodat, fchownat, fstatat,
futimesat, linkat, mkdirat, mkfifoat, mknodat, readlinkat, renameat,
symlinkat, unlinkat to list of implemented Solaris functions.

https://sourceware.org/git/?p=newlib-cygwin.git;a=blobdiff;f=winsup/cygwin/syscalls.cc;h=1a2572186c320c15275f458a8dad7623e09d40b7;hp=28533a58b961e2e379a6bda3904e7ecfa072cf75;hb=c57b57e5c43ab112e50d5e214b8cef61f8027946;hpb=ca48eb65e9f332484b1fe00ae373a1121091cbfb

and check around that time and search the logs for others; POSIX compat xref in:

https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=winsup/doc/posix.xml;h=8e88245acc0f6e1de10c8fecd81be6e1529dd0a2;hb=HEAD


readable:

https://cygwin.com/cygwin-api/

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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