From: Andrii Nakryiko <andriin@fb.com>
Date: Fri, 31 Jul 2020 11:28:29 -0700
Subject: tools/bpftool: Add `link detach` subcommand
Patch-mainline: v5.9-rc1
Git-commit: 0e8c7c07f090668566db2030a027a360ffd00938
References: bsc#1177028
Add ability to force-detach BPF link. Also add missing error message, if
specified link ID is wrong.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200731182830.286260-5-andriin@fb.com
Acked-by: Gary Lin <glin@suse.com>
---
tools/bpf/bpftool/link.c | 37 ++++++++++++++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -22,6 +22,8 @@ static const char * const link_type_name
static int link_parse_fd(int *argc, char ***argv)
{
+ int fd;
+
if (is_prefix(**argv, "id")) {
unsigned int id;
char *endptr;
@@ -35,7 +37,10 @@ static int link_parse_fd(int *argc, char
}
NEXT_ARGP();
- return bpf_link_get_fd_by_id(id);
+ fd = bpf_link_get_fd_by_id(id);
+ if (fd < 0)
+ p_err("failed to get link with ID %d: %s", id, strerror(errno));
+ return fd;
} else if (is_prefix(**argv, "pinned")) {
char *path;
@@ -316,6 +321,34 @@ static int do_pin(int argc, char **argv)
return err;
}
+static int do_detach(int argc, char **argv)
+{
+ int err, fd;
+
+ if (argc != 2) {
+ p_err("link specifier is invalid or missing\n");
+ return 1;
+ }
+
+ fd = link_parse_fd(&argc, &argv);
+ if (fd < 0)
+ return 1;
+
+ err = bpf_link_detach(fd);
+ if (err)
+ err = -errno;
+ close(fd);
+ if (err) {
+ p_err("failed link detach: %s", strerror(-err));
+ return 1;
+ }
+
+ if (json_output)
+ jsonw_null(json_wtr);
+
+ return 0;
+}
+
static int do_help(int argc, char **argv)
{
if (json_output) {
@@ -326,6 +359,7 @@ static int do_help(int argc, char **argv
fprintf(stderr,
"Usage: %1$s %2$s { show | list } [LINK]\n"
" %1$s %2$s pin LINK FILE\n"
+ " %1$s %2$s detach LINK\n"
" %1$s %2$s help\n"
"\n"
" " HELP_SPEC_LINK "\n"
@@ -341,6 +375,7 @@ static const struct cmd cmds[] = {
{ "list", do_show },
{ "help", do_help },
{ "pin", do_pin },
+ { "detach", do_detach },
{ 0 }
};