x/sys/unix: please add syscall definitions for FreeBSD

[yurivict]

See the downstream bug report: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230736

[ianlancetaylor]

The bug report is asking for at least the following system calls to be added to the FreeBSD target:

SYS_SEMOP
SYS_SEMGET
SYS_SEMCTL
SYS_MSGSND
SYS_MSGRCV
SYS_MSGGET
SYS_MSGCTL
SYS_SHMAT
SYS_SHMDT
SYS_SHMGET

These values should not be added to the syscall package, which is frozen, but they should be added to the golang.org/x/sys/unix package.

[yurivict]

Actually, all system calls that are defined in the FreeBSD kernel should be defined in go, including module-dependent ones.

[ianlancetaylor]

@yurivict I agree. Not sure what you mean by writing "actually."

[yurivict]

Some of the system calls are labeled as optional. All of them, including the optional ones, should be available in go.

[jharshman]

Just poking around to see why this is, and it looks like there are a lot of un-implemented system calls. See syscall_freebsd.go

The mksysnum_freebsd.pl regex filters syscalls of type NOSTD which accounts for missing ones.

[yurivict]

mksysnum_freebsd.pl shouldn't filter out NOSTD calls.
They are regular calls defined in kernel modules that might be missing on some systems, but are usually present.

[gopherbot]

Change https://golang.org/cl/129855 mentions this issue: unix: add NOSTD syscall numbers on FreeBSD