f120919f99
Function open_obj_pinned() prints error messages when it fails to open a
link in the BPF virtual file system. However, in some occasions it is
not desirable to print an error, for example when we parse all links
under the bpffs root, and the error is due to some paths actually being
symbolic links.
Example output:
# ls -l /sys/fs/bpf/
lrwxrwxrwx 1 root root 0 Oct 18 19:00 ip -> /sys/fs/bpf/tc/
drwx------ 3 root root 0 Oct 18 19:00 tc
lrwxrwxrwx 1 root root 0 Oct 18 19:00 xdp -> /sys/fs/bpf/tc/
# bpftool --bpffs prog show
Error: bpf obj get (/sys/fs/bpf): Permission denied
Error: bpf obj get (/sys/fs/bpf): Permission denied
# strace -e bpf bpftool --bpffs prog show
bpf(BPF_OBJ_GET, {pathname="/sys/fs/bpf/ip", bpf_fd=0}, 72) = -1 EACCES (Permission denied)
Error: bpf obj get (/sys/fs/bpf): Permission denied
bpf(BPF_OBJ_GET, {pathname="/sys/fs/bpf/xdp", bpf_fd=0}, 72) = -1 EACCES (Permission denied)
Error: bpf obj get (/sys/fs/bpf): Permission denied
...
To fix it, pass a bool as a second argument to the function, and prevent
it from printing an error when the argument is set to true.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.