Handle EINTR #657
Description
In WebKit/WebKit#34268 we discovered that some code I copied from bubblewrap is not properly handling EINTR, specifically the calls to sendmsg() and recvmsg() in utils.c.
I had considered submitting a quick pull request, but quickly discovered these aren't the only places. E.g. the call to openat() in load_file_at() in utils.c has the same problem. Unfortunately there's no easy way to check a large codebase for places with missing error handling.