Merge branch 'libbpf: Textual representation of enums'

Daniel Müller says:

====================

This patch set introduces the means for querying a textual representation of
the following BPF related enum types:
- enum bpf_map_type
- enum bpf_prog_type
- enum bpf_attach_type
- enum bpf_link_type

To make that possible, we introduce a new public function for each of the types:
libbpf_bpf_<type>_type_str.

Having a way to query a textual representation has been asked for in the past
(by systemd, among others). Such representations can generally be useful in
tracing and logging contexts, among others. At this point, at least one client,
bpftool, maintains such a mapping manually, which is prone to get out of date as
new enum variants are introduced. libbpf is arguably best situated to keep this
list complete and up-to-date. This patch series adds BTF based tests to ensure
that exhaustiveness is upheld moving forward.

The libbpf provided textual representation can be inferred from the
corresponding enum variant name by removing the prefix and lowercasing the
remainder. E.g., BPF_PROG_TYPE_SOCKET_FILTER -> socket_filter. Unfortunately,
bpftool does not use such a programmatic approach for some of the
bpf_attach_type variants. We decided in favor of changing its behavior to work
with libbpf representations. However, for user inputs, specifically, we do
maintain support for the traditionally used names around (please see patch
"bpftool: Use libbpf_bpf_attach_type_str").

The patch series is structured as follows:
- for each enumeration type in {bpf_prog_type, bpf_map_type, bpf_attach_type,
  bpf_link_type}:
  - we first introduce the corresponding public libbpf API function
  - we then add BTF based self-tests
  - we lastly adjust bpftool to use the libbpf provided functionality

Signed-off-by: Daniel Müller <deso@posteo.net>
Cc: Quentin Monnet <quentin@isovalent.com>
---
Changelog:
v3 -> v4:
- use full string comparison for newly added attach types
- switched away from erroneously used kdoc-style comments
- removed unused prog_types variable and containing section from
  test_bpftool_synctypes.py
- adjusted wording in documentation of get_types_from_array function
- split various test_bpftool_synctypes.py changes into commits where they are
  required to eliminate temporary failures of this test

v2 -> v3:
- use LIBBPF_1.0.0 section in libbpf.map for newly added exports

v1 -> v2:
- adjusted bpftool to work with algorithmically determined attach types as
  libbpf now uses (just removed prefix from enum name and lowercased the rest)
  - adjusted tests, man page, and completion script to work with the new names
  - renamed bpf_attach_type_str -> bpf_attach_type_input_str
  - for input: added special cases that accept the traditionally used strings as
    well
- changed 'char const *' -> 'const char *'
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

1 files changed, 36 insertions, 46 deletions

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index c740142c24d8..a45b42ee8ab0 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -31,52 +31,6 @@
 #define BPF_FS_MAGIC		0xcafe4a11
 #endif
 
-const char * const attach_type_name[__MAX_BPF_ATTACH_TYPE] = {
-	[BPF_CGROUP_INET_INGRESS]	= "ingress",
-	[BPF_CGROUP_INET_EGRESS]	= "egress",
-	[BPF_CGROUP_INET_SOCK_CREATE]	= "sock_create",
-	[BPF_CGROUP_INET_SOCK_RELEASE]	= "sock_release",
-	[BPF_CGROUP_SOCK_OPS]		= "sock_ops",
-	[BPF_CGROUP_DEVICE]		= "device",
-	[BPF_CGROUP_INET4_BIND]		= "bind4",
-	[BPF_CGROUP_INET6_BIND]		= "bind6",
-	[BPF_CGROUP_INET4_CONNECT]	= "connect4",
-	[BPF_CGROUP_INET6_CONNECT]	= "connect6",
-	[BPF_CGROUP_INET4_POST_BIND]	= "post_bind4",
-	[BPF_CGROUP_INET6_POST_BIND]	= "post_bind6",
-	[BPF_CGROUP_INET4_GETPEERNAME]	= "getpeername4",
-	[BPF_CGROUP_INET6_GETPEERNAME]	= "getpeername6",
-	[BPF_CGROUP_INET4_GETSOCKNAME]	= "getsockname4",
-	[BPF_CGROUP_INET6_GETSOCKNAME]	= "getsockname6",
-	[BPF_CGROUP_UDP4_SENDMSG]	= "sendmsg4",
-	[BPF_CGROUP_UDP6_SENDMSG]	= "sendmsg6",
-	[BPF_CGROUP_SYSCTL]		= "sysctl",
-	[BPF_CGROUP_UDP4_RECVMSG]	= "recvmsg4",
-	[BPF_CGROUP_UDP6_RECVMSG]	= "recvmsg6",
-	[BPF_CGROUP_GETSOCKOPT]		= "getsockopt",
-	[BPF_CGROUP_SETSOCKOPT]		= "setsockopt",
-	[BPF_SK_SKB_STREAM_PARSER]	= "sk_skb_stream_parser",
-	[BPF_SK_SKB_STREAM_VERDICT]	= "sk_skb_stream_verdict",
-	[BPF_SK_SKB_VERDICT]		= "sk_skb_verdict",
-	[BPF_SK_MSG_VERDICT]		= "sk_msg_verdict",
-	[BPF_LIRC_MODE2]		= "lirc_mode2",
-	[BPF_FLOW_DISSECTOR]		= "flow_dissector",
-	[BPF_TRACE_RAW_TP]		= "raw_tp",
-	[BPF_TRACE_FENTRY]		= "fentry",
-	[BPF_TRACE_FEXIT]		= "fexit",
-	[BPF_MODIFY_RETURN]		= "mod_ret",
-	[BPF_LSM_MAC]			= "lsm_mac",
-	[BPF_SK_LOOKUP]			= "sk_lookup",
-	[BPF_TRACE_ITER]		= "trace_iter",
-	[BPF_XDP_DEVMAP]		= "xdp_devmap",
-	[BPF_XDP_CPUMAP]		= "xdp_cpumap",
-	[BPF_XDP]			= "xdp",
-	[BPF_SK_REUSEPORT_SELECT]	= "sk_skb_reuseport_select",
-	[BPF_SK_REUSEPORT_SELECT_OR_MIGRATE]	= "sk_skb_reuseport_select_or_migrate",
-	[BPF_PERF_EVENT]		= "perf_event",
-	[BPF_TRACE_KPROBE_MULTI]	= "trace_kprobe_multi",
-};
-
 void p_err(const char *fmt, ...)
 {
 	va_list ap;
@@ -1009,3 +963,39 @@ bool equal_fn_for_key_as_id(const void *k1, const void *k2, void *ctx)
 {
 	return k1 == k2;
 }
+
+const char *bpf_attach_type_input_str(enum bpf_attach_type t)
+{
+	switch (t) {
+	case BPF_CGROUP_INET_INGRESS:		return "ingress";
+	case BPF_CGROUP_INET_EGRESS:		return "egress";
+	case BPF_CGROUP_INET_SOCK_CREATE:	return "sock_create";
+	case BPF_CGROUP_INET_SOCK_RELEASE:	return "sock_release";
+	case BPF_CGROUP_SOCK_OPS:		return "sock_ops";
+	case BPF_CGROUP_DEVICE:			return "device";
+	case BPF_CGROUP_INET4_BIND:		return "bind4";
+	case BPF_CGROUP_INET6_BIND:		return "bind6";
+	case BPF_CGROUP_INET4_CONNECT:		return "connect4";
+	case BPF_CGROUP_INET6_CONNECT:		return "connect6";
+	case BPF_CGROUP_INET4_POST_BIND:	return "post_bind4";
+	case BPF_CGROUP_INET6_POST_BIND:	return "post_bind6";
+	case BPF_CGROUP_INET4_GETPEERNAME:	return "getpeername4";
+	case BPF_CGROUP_INET6_GETPEERNAME:	return "getpeername6";
+	case BPF_CGROUP_INET4_GETSOCKNAME:	return "getsockname4";
+	case BPF_CGROUP_INET6_GETSOCKNAME:	return "getsockname6";
+	case BPF_CGROUP_UDP4_SENDMSG:		return "sendmsg4";
+	case BPF_CGROUP_UDP6_SENDMSG:		return "sendmsg6";
+	case BPF_CGROUP_SYSCTL:			return "sysctl";
+	case BPF_CGROUP_UDP4_RECVMSG:		return "recvmsg4";
+	case BPF_CGROUP_UDP6_RECVMSG:		return "recvmsg6";
+	case BPF_CGROUP_GETSOCKOPT:		return "getsockopt";
+	case BPF_CGROUP_SETSOCKOPT:		return "setsockopt";
+	case BPF_TRACE_RAW_TP:			return "raw_tp";
+	case BPF_TRACE_FENTRY:			return "fentry";
+	case BPF_TRACE_FEXIT:			return "fexit";
+	case BPF_MODIFY_RETURN:			return "mod_ret";
+	case BPF_SK_REUSEPORT_SELECT:		return "sk_skb_reuseport_select";
+	case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE:	return "sk_skb_reuseport_select_or_migrate";
+	default:	return libbpf_bpf_attach_type_str(t);
+	}
+}