Commit Graph

5 Commits

Author SHA1 Message Date
Michal Privoznik
95b9db4ee2 lib: Prefer WITH_* prefix for #if conditionals
Currently, we are mixing: #if HAVE_BLAH with #if WITH_BLAH.
Things got way better with Pavel's work on meson, but apparently,
mixing these two lead to confusing and easy to miss bugs (see
31fb929eca for instance). While we were forced to use HAVE_
prefix with autotools, we are free to chose our own prefix with
meson and since WITH_ prefix appears to be more popular let's use
it everywhere.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-09-02 10:28:10 +02:00
Michal Privoznik
9fe6c1dc7f virbpf: Set errno instead of reporting errors
The virbpf module wraps syscalls to BPF. However, if the kernel
headers used at the compile time don't have support for BPF the
module offers stubs which return a negative one to signal error
to the caller. But there is a slight discrepancy between real
functions and these stubs. While the former set errno and return
-1 the latter report an error (without setting the errno) and
return -1. This is not optimal because the caller might see stale
errno and overwrite the error message with a less accurate one.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2020-03-10 17:10:57 +01:00
Michal Privoznik
02bf7cc68b virbpf: Fix typecast to __aligned_u64 type
In functions implemented here we fill this attr union (type of
bpf_attr) and just pass it to syscall(2). Thing is that some of
the union members are type of __aligned_u64. This is not regular
uint64_t. This one is explicitly aligned to 8 bytes, while
uint64_t can be aligned to 4 bytes (on 32 bits). We've used
explicit typecast to uint64_t to shut compiler which would
otherwise complain of assigning a pointer into an integer. Well,
we have uintptr_t just for that.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2019-11-18 08:59:13 +01:00
Michal Privoznik
c07a33bef9 virbpf: Check if syscall() is available
There are some OSes which don't have syscall() nor
<sys/syscall.h>. We already check for the header file in
configure phase, so we just need to add check for
HAVE_SYS_SYSCALL_H to HAVE_DECL_BPF_PROG_QUERY.

While I'm at it, some header files we are including are not
needed, so their includes can be safely dropped.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2019-11-16 06:39:23 +01:00
Pavel Hrdina
07946d6e39 util: introduce virbpf helpers
In order to implement devices controller with cgroup v2 we need to
add support for BPF programs, cgroup v2 doesn't have devices controller.

This introduces required helpers wrapping linux syscalls.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-11-15 12:58:00 +01:00