On 10 Mar 2009, at 03:21, Daniel Eischen wrote:
On Wed, 26 Mar 2008, Doug Rabson wrote:
dfr 2008-03-26 15:23:13 UTC
FreeBSD src repository
Modified files:
lib/libc/sys Symbol.map fcntl.2
[ ... ]
sys/sys fcntl.h lockf.h
[ ... ]
Log:
Add the new kernel-mode NFS Lock Manager. To use it instead of the
user-mode lock manager, build a kernel with the NFSLOCKD option and
add '-k' to 'rpc_lockd_flags' in rc.conf.
Sorry to notice this 1 year too late, but doesn't this
break ABI? You have changed the size (increased) of
struct flock and haven't really provided a compat version
of fcntl() that will work with binaries built before
the change.
I added new fcntl commands for the new structures. The old commands
were renamed to F_OGETLK, F_OSETLK and F_OSETLKW and continue to use
the old structures. A new kernel translates old fcntl commands to the
equivalent new commands. A new libc will detect when its running on an
old kernel and will translate the new fcntl commands to the equivalent
old ones.
Is there any way that the new field can be accidentally
used by the kernel from a binary built against the older
struct flock?
No.
Now that we have symbol versioning, the way this normally
should be handled is by adding a compat fcntl() for
FBSD_1.0 in libc, and placing the new fcntl() in FBSD_1.1.
And since libthr wraps fcntl() for cancellation points,
I believe it would also need the same compat functions.
I thought about this but in the end it was simpler to add new fcntl
commands. The libthr compat issue is dealt with by calling
__fcntl_compat() for commands other than F_DUPFD, F_SETFD, F_SETFL,
F_GETFD or F_GETFL.
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