integer truncation in truncate on Windows

[simonster]

While ios_trunc accepts a size argument of type size_t, it calls _chsize, which takes a long (32-bit int on Windows), and it doesn't check for overflow. As a result, this fails:

open("some_file_name", "w") do f
    truncate(f, 2^31+1)
end

ios_trunc should probably be modified to use _chsize_s.

(Originally reported as JuliaIO/JLD2.jl#50.)

[jaakkor2]

Looks like it used to be _chsize_s, but was changed to _chsize here https://github.com/JuliaLang/julia/pull/3011/files back in 2013 due to MinGW compilation problems.

If defined(__MINGW32__) continue to use _chsize, otherwise _chsize_s on Windows?

[vtjnash]

MinGW is long dead

[jaakkor2]

Consequence of this bug: on Windows 64-bit files larger than 2 GB cannot be truncated. For example, JLD2-files are now limited to 2 GB size.

Looks like cygwin64/mingw64-x86_64 is used to compile the version downloadable at https://julialang.org/downloads/ . And looks like mingw64 has _chsize_s defined in mingw-w64/mingw-w64-crt/secapi/_chsize_s.c . But I do not find references to --enable-secure-api option in Julia code.

If we are targeting systems newer than Windows XP, _chsize_s should be ok, but I have no possibility to do testing now. Help wanted :)