Commit Graph

23 Commits

Author SHA1 Message Date
Sven Anderson
05b4e70014 cutil: enable PtrGuard by default
Signed-off-by: Sven Anderson <sven@redhat.com>
2022-04-28 14:39:48 +00:00
Robert Vasek
74ca850366 cutil: added BufferGroup
BufferGroup is a helper structure that holds Go-allocated slices of
C-allocated strings and their respective lengths. Useful for C functions
that consume byte buffers with explicit length instead of null-terminated
strings.
2022-03-09 14:02:56 +00:00
Sven Anderson
3b859f8f80 cutil: fix revive error
Signed-off-by: Sven Anderson <sven@redhat.com>
2022-02-08 15:17:34 +00:00
Robert Vasek
0443277bb9 rados: implement binding for rados_write_op_cmpext
This commit implements binding for rados_write_op_cmpext RADOS Write operation.
Includes a unit test.

Signed-off-by: Robert Vasek <robert.vasek@cern.ch>
2021-12-08 19:07:12 +00:00
Sven Anderson
87f4563118 format: run gofmt on all files
Signed-off-by: Sven Anderson <sven@redhat.com>
2021-10-04 18:58:35 +00:00
Sven Anderson
3210885d21 ptrguard: simplify pointer size assert
Signed-off-by: Sven Anderson <sven@redhat.com>
2021-10-04 06:58:23 +00:00
Sven Anderson
46300ecae8 cutil: fix race condition in ptrguard tests
The finalizer of an object is called in a separate go routine, so we
might have to check several times for its completion.

Fixes: #545

Signed-off-by: Sven Anderson <sven@redhat.com>
2021-08-12 10:02:40 -04:00
Sven Anderson
1c719b199e tests: add benchmarks for PtrGuard related types
Signed-off-by: Sven Anderson <sven@redhat.com>
2021-06-01 09:19:59 +00:00
Sven Anderson
c45fa95b32 rados: remove pointer arithmetic on C-buffers
This change uses slices on top of C allocated array memory in order
to have a simple (no pointer arithmetic) and safe (boundary-checked)
access to its elements.

Signed-off-by: Sven Anderson <sven@redhat.com>
2021-05-03 16:20:34 +00:00
Sven Anderson
014a3f6308 ptrguard: assert pointer and uintptr have same size
Uintptr are guaranteed to be at least of the size of a pointer.  However, in
theory it could be larger.  Since the code of PtrGuard assumes both have the
same size and to be on the safe side, this change adds a compile-time check,
that the sizes of uintptr and pointers are the same.

Signed-off-by: Sven Anderson <sven@anderson.de>
2021-03-26 11:41:14 +00:00
Sven Anderson
1c72979ce0 ptrguard: assert that //go:uintptrescapes actually works
This adds a test that assures that the special //go:uintptrescapes comment
before the storeUntilRelease() function works as intended, that is the
garbage collector doesn't touch the object referenced by the uintptr until
the function returns after Release() is called.  The test will fail if the
//go:uintptrescapes comment is disabled (removed) or stops working in future
versions of go.

Signed-off-by: Sven Anderson <sven@redhat.com>
2021-03-19 09:47:19 -04:00
Sven Anderson
b8a803ccbb cutil: use SyncBuffer for iovec type
The main motivation for PtrGuard was read and write buffers as they
are used in iovec.  This change uses SyncBuffer for the iovec
implementation, so that the no-copy PtrGuard implementation can be
enabled with the with_ptrguard build tag.

Signed-off-by: Sven Anderson <sven@redhat.com>
2021-02-08 11:09:25 -05:00
Sven Anderson
430dea5b7f cutil: add SyncBuffer abstraction layer to PtrGuard
In order to be able to swich on and off PtrGuard usage, SyncBuffer
implements a typical usage pattern of PtrGuard, that is a data buffer
referenced from inside a C allocated struct, in two ways: 1) using a
PtrGuard to dierctly store a pointer to the Go buffer in C memory, or
2) allocating a C buffer of same size and syncing data back with
C.memcpy().  The implementation can be chosen with the with_ptrguard
build tag.

Signed-off-by: Sven Anderson <sven@redhat.com>
2021-02-08 11:09:25 -05:00
Sven Anderson
ac57250a5b cutil: add some useful function aliases
Signed-off-by: Sven Anderson <sven@redhat.com>
2021-02-08 11:09:25 -05:00
Sven Anderson
2bfdee2508 cutil: add test for PtrGuard
Signed-off-by: Sven Anderson <sven@redhat.com>
2021-02-08 14:50:56 +00:00
Sven Anderson
0451edaf71 cutil: add PtrGuard for storing Go pointers in C memory
Signed-off-by: Sven Anderson <sven@redhat.com>
2021-02-08 14:50:56 +00:00
Sven Anderson
0130c60281 cutil: add general C type, function and const aliases
This change adds a new pointer alias CPtr, that should always only
contains pointers to C allocated memory and should always used for
such pointers in order to keep them separate from Go pointers more
easily. This is helpful, since only CPtr are allowed to be stored in
C allocated memory, and Go pointers can only be passed to C functions
if they don't point to memory not containing Go pointers again, that
is all pointers in such memory must be CPtr.

The change also adds aliases for C.malloc and C.free that return and
accept the CPtr type as a little safety measure.

Additionally there are some useful constants defined.

Signed-off-by: Sven Anderson <sven@redhat.com>
2021-01-20 14:46:03 +00:00
Sven Anderson
c8f26a841b rbd: eliminate invalid unsafe.Pointers
Although it seems to be stable with the current Go versions,
unsafe.Pointers that are created by applying arithmetic on nil
pointers are explicitly not allowed[1], and could potentially lead to
panics by the garbage collector.  To be on the safe side, this change
goes back to minimal inline wrappers for the callback registrations,
which should be zero-cost.  For the callbacks themselves fortunately
no wrappers are required, because CGo happily converts void* to
uintptr arguments.  The potentially problematic VoidPtr helper is
removed again.

[1] https://golang.org/pkg/unsafe/#Pointer

Signed-off-by: Sven Anderson <sven@redhat.com>
2020-11-09 08:58:22 +00:00
John Mulligan
ebea82dda5 cutil: add Iovec type wrapping C struct iovec arrays
This type is useful for passing disparate buffers to be read or
written in a single call. Functions using this type exist in cephfs
and rbd. Currently this is needed for cephfs calls.

Signed-off-by: John Mulligan <jmulligan@redhat.com>
2020-08-28 10:07:34 -04:00
Sven Anderson
4706453428 rbd: remove unnecessary C wrapper functions
Signed-off-by: Sven Anderson <sven@redhat.com>
2020-08-28 09:51:06 -04:00
John Mulligan
e5d1a53060 cutil: add SplitBuffer and SplitSparseBuffer helper functions
Add SplitBuffer and SplitSparseBuffer functions for extracting a list
of strings from a single buffer, typically returned in C code, from
a single Go buffer. The SplitBuffer variant will return empty strings
if multiple nulls are found in sequence, assuming that the C code
packs data between on single null byte (expect the final byte).
The SplitSparseBuffer variant assumes that the C code may not
tightly pack the data with single null bytes and thus will not
return any empty strings (unless the input buffer is empty
or only contains nulls).
Most of the code in the go-ceph codebase is doing the latter but
probably should have been doing the former. Thus both approaches
are provided.

Signed-off-by: John Mulligan <jmulligan@redhat.com>
2020-07-23 16:38:39 -04:00
John Mulligan
e2a78eec02 cutil: allow passing free functions to command output type
The *_command functions in librados and libcephfs document the use
of specific free functions for data allocated. These functions are
currently just wrappers around C's free() function. However, to be
more strictly compliant this change adds a free-function callback
to the CommandOutput type and the specific free functions are now
used outside the unit tests.

Signed-off-by: John Mulligan <jmulligan@redhat.com>
2020-05-12 17:18:08 -04:00
John Mulligan
e40744fdf6 cutil: add a new internal package for c+go utility functions
Now we have sufficient boilerplate in our code for interacting with
various types and ceph calls with similar needs we establish a new
internal package, "cutil" (C utilities).

Note that many of the return types are wrapped. This is due to the
limits placed on us by cgo.  Despite the irritating limitations Go
places on "exporting" C types it still ought to help in the long run for
patterns that are very common or patterns that are subtle and we want to
write specific tests for.

Signed-off-by: John Mulligan <jmulligan@redhat.com>
2020-05-12 17:18:08 -04:00