x/sys: add BLK* constants (specifically BLKGETSIZE64 and BLKRRPART)

[stapelberg]

I’m about to send the following change for review, adding the BLK* constants which I’m using in a program to re-read the partition table:

--- i/unix/mkerrors.sh
+++ w/unix/mkerrors.sh
@@ -353,7 +353,8 @@ ccflags="$@"
                $2 ~ /^GRND_/ ||
                $2 ~ /^SPLICE_/ ||
                $2 !~ "WMESGLEN" &&
-               $2 ~ /^W[A-Z0-9]+$/ {printf("\t%s = C.%s\n", $2, $2)}
+               $2 ~ /^W[A-Z0-9]+$/ ||
+               $2 ~ /^BLK/ {printf("\t%s = C.%s\n", $2, $2)}
                $2 ~ /^__WCOREFLAG$/ {next}
                $2 ~ /^__W[A-Z0-9]+$/ {printf("\t%s = C.%s\n", substr($2,3), $2)}

I have a question about the process, though: when running GOARCH=amd64 GOOS=linux ./mkerrors.sh -m64 |gofmt >zerrors_linux_amd64.go I get a significant diff. I’m running the command on a Debian stretch system with linux-libc-dev 4.9.2-2.

Should the command be run on a specific system? If so, which one? Is there documentation about this which I’ve missed?

[ianlancetaylor]

Diffs are unfortunately expected, for various historical reasons. The workaround is to run the script and then discard any changes unrelated to what you are doing. At some point we should try to clean this up, but of course that should be independent of any real changes.

[bradfitz]

Cleaning up the process for regenerating the files is bug #15282.

[gopherbot]

CL https://golang.org/cl/37640 mentions this issue.