Consider replacing GetTempFileName with GetTempPath and GetRandomFileName

[jbagga]

dotnet-install.ps1 uses GetTempFileName, however

The GetTempFileName method will raise an IOException if it is used to create more than 65535 files without deleting previous temporary files.

See https://github.com/aspnet/Coherence-Signed/issues/510 for more information.

cc @Eilon

[birbilis]

Maybe should consider fixing GetTempFileName? The average programmer wouldn't expect it bombs at 65535 files

[birbilis]

seeing the fix at https://github.com/dotnet/cli/blob/f0ee1e44114f161ce9268103d18ce32d2a995d0f/scripts/obtain/dotnet-install.ps1#L631 and at another line in there - copying the url here since the dotnet/aspnetcore-internal link above is not public or is broken link

[birbilis]

note that the original code was creating an empty temp file (that is the behaviour of GetTempFilename). For a replacement function that tries to do that (doesn't try it in a loop to avoid infinite recursion if one can't write to temp folder for anyother reason) see https://dotnetfiddle.net/bmFVSX