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From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
	<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
	Andrii Nakryiko <andriin@fb.com>, Hao Luo <haoluo@google.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Song Liu <songliubraving@fb.com>,
	Quentin Monnet <quentin@isovalent.com>
Subject: [RFC PATCH bpf-next 5/8] tools/bpftool: minimize bootstrap bpftool
Date: Fri, 12 Jun 2020 15:31:47 -0700	[thread overview]
Message-ID: <20200612223150.1177182-6-andriin@fb.com> (raw)
In-Reply-To: <20200612223150.1177182-1-andriin@fb.com>

Build minimal "bootstrap mode" bpftool to enable skeleton (and, later,
vmlinux.h generation), instead of building almost complete, but slightly
different (w/o skeletons, etc) bpftool to bootstrap complete bpftool build.

Current approach doesn't scale well (engineering-wise) when adding more BPF
programs to bpftool and other complicated functionality, as it requires
constant adjusting of the code to work in both bootstrapped mode and normal
mode.

So it's better to build only minimal bpftool version that supports only BPF
skeleton code generation and BTF-to-C conversion. Thankfully, this is quite
easy to accomplish due to internal modularity of bpftool commands. This will
also allow to keep adding new functionality to bpftool in general, without the
need to care about bootstrap mode for those new parts of bpftool.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/bpf/bpftool/.gitignore |  2 +-
 tools/bpf/bpftool/Makefile   | 30 +++++++++++++-----------------
 tools/bpf/bpftool/main.c     | 11 +++++++++--
 tools/bpf/bpftool/main.h     | 27 +++++++++++++++------------
 4 files changed, 38 insertions(+), 32 deletions(-)

diff --git a/tools/bpf/bpftool/.gitignore b/tools/bpf/bpftool/.gitignore
index 26cde83e1ca3..ce721adf3161 100644
--- a/tools/bpf/bpftool/.gitignore
+++ b/tools/bpf/bpftool/.gitignore
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 *.d
-/_bpftool
+/bpftool-bootstrap
 /bpftool
 bpftool*.8
 bpf-helpers.*
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 9e85f101be85..eec2da4d45d2 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -116,40 +116,36 @@ CFLAGS += -DHAVE_LIBBFD_SUPPORT
 SRCS += $(BFD_SRCS)
 endif
 
+BPFTOOL_BOOTSTRAP := $(if $(OUTPUT),$(OUTPUT)bpftool-bootstrap,./bpftool-bootstrap)
+
+BOOTSTRAP_OBJS = $(addprefix $(OUTPUT),main.o common.o json_writer.o gen.o btf.o)
 OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
-_OBJS = $(filter-out $(OUTPUT)prog.o,$(OBJS)) $(OUTPUT)_prog.o
 
-ifeq ($(feature-clang-bpf-global-var),1)
-	__OBJS = $(OBJS)
-else
-	__OBJS = $(_OBJS)
+ifneq ($(feature-clang-bpf-global-var),1)
+	CFLAGS += -DBPFTOOL_WITHOUT_SKELETONS
 endif
 
-$(OUTPUT)_prog.o: prog.c
-	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -DBPFTOOL_WITHOUT_SKELETONS -o $@ $<
-
-$(OUTPUT)_bpftool: $(_OBJS) $(LIBBPF)
-	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(_OBJS) $(LIBS)
-
 skeleton/profiler.bpf.o: skeleton/profiler.bpf.c $(LIBBPF)
 	$(QUIET_CLANG)$(CLANG) \
 		-I$(srctree)/tools/include/uapi/ \
 		-I$(LIBBPF_PATH) -I$(srctree)/tools/lib \
 		-g -O2 -target bpf -c $< -o $@
 
-profiler.skel.h: $(OUTPUT)_bpftool skeleton/profiler.bpf.o
-	$(QUIET_GEN)$(OUTPUT)./_bpftool gen skeleton skeleton/profiler.bpf.o > $@
+profiler.skel.h: $(BPFTOOL_BOOTSTRAP) skeleton/profiler.bpf.o
+	$(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) gen skeleton skeleton/profiler.bpf.o > $@
 
 $(OUTPUT)prog.o: prog.c profiler.skel.h
-	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<
 
 $(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c
 	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<
 
 $(OUTPUT)feature.o: | zdep
 
-$(OUTPUT)bpftool: $(__OBJS) $(LIBBPF)
-	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(__OBJS) $(LIBS)
+$(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(BOOTSTRAP_OBJS) $(LIBS)
+
+$(OUTPUT)bpftool: $(OBJS) $(LIBBPF)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)
 
 $(OUTPUT)%.o: %.c
 	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<
@@ -157,7 +153,7 @@ $(OUTPUT)%.o: %.c
 clean: $(LIBBPF)-clean
 	$(call QUIET_CLEAN, bpftool)
 	$(Q)$(RM) -- $(OUTPUT)bpftool $(OUTPUT)*.o $(OUTPUT)*.d
-	$(Q)$(RM) -- $(OUTPUT)_bpftool profiler.skel.h skeleton/profiler.bpf.o
+	$(Q)$(RM) -- $(BPFTOOL_BOOTSTRAP) profiler.skel.h skeleton/profiler.bpf.o
 	$(Q)$(RM) -r -- $(OUTPUT)libbpf/
 	$(call QUIET_CLEAN, core-gen)
 	$(Q)$(RM) -- $(OUTPUT)FEATURE-DUMP.bpftool
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 46bd716a9d86..bf4d7487552a 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -92,9 +92,16 @@ int cmd_select(const struct cmd *cmds, int argc, char **argv,
 	if (argc < 1 && cmds[0].func)
 		return cmds[0].func(argc, argv);
 
-	for (i = 0; cmds[i].func; i++)
-		if (is_prefix(*argv, cmds[i].cmd))
+	for (i = 0; cmds[i].cmd; i++) {
+		if (is_prefix(*argv, cmds[i].cmd)) {
+			if (!cmds[i].func) {
+				p_err("command '%s' is not supported in bootstrap mode",
+				      cmds[i].cmd);
+				return -1;
+			}
 			return cmds[i].func(argc - 1, argv + 1);
+		}
+	}
 
 	help(argc - 1, argv + 1);
 
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 4338ab9d86d4..aad7be74e8a7 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -194,19 +194,22 @@ int mount_bpffs_for_pin(const char *name);
 int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(int *, char ***));
 int do_pin_fd(int fd, const char *name);
 
-int do_prog(int argc, char **arg);
-int do_map(int argc, char **arg);
-int do_link(int argc, char **arg);
-int do_event_pipe(int argc, char **argv);
-int do_cgroup(int argc, char **arg);
-int do_perf(int argc, char **arg);
-int do_net(int argc, char **arg);
-int do_tracelog(int argc, char **arg);
-int do_feature(int argc, char **argv);
-int do_btf(int argc, char **argv);
+/* commands available in bootstrap mode */
 int do_gen(int argc, char **argv);
-int do_struct_ops(int argc, char **argv);
-int do_iter(int argc, char **argv);
+int do_btf(int argc, char **argv);
+
+/* non-bootstrap only commands */
+int do_prog(int argc, char **arg) __weak;
+int do_map(int argc, char **arg) __weak;
+int do_link(int argc, char **arg) __weak;
+int do_event_pipe(int argc, char **argv) __weak;
+int do_cgroup(int argc, char **arg) __weak;
+int do_perf(int argc, char **arg) __weak;
+int do_net(int argc, char **arg) __weak;
+int do_tracelog(int argc, char **arg) __weak;
+int do_feature(int argc, char **argv) __weak;
+int do_struct_ops(int argc, char **argv) __weak;
+int do_iter(int argc, char **argv) __weak;
 
 int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
 int prog_parse_fd(int *argc, char ***argv);
-- 
2.24.1


  parent reply	other threads:[~2020-06-12 22:34 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-12 22:31 [RFC PATCH bpf-next 0/8] libbpf ksym support and bpftool show PIDs Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 1/8] libbpf: generalize libbpf externs support Andrii Nakryiko
     [not found]   ` <CA+khW7hAYVdoQX5-j0z1iGEVZeww4BBu4NXzy5eS5OwDRYqe2w@mail.gmail.com>
2020-06-15 18:55     ` Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 2/8] libbpf: add support for extracting kernel symbol addresses Andrii Nakryiko
     [not found]   ` <CA+khW7hFZzp_K_xydSFw0O3LYB22_fC=Z4wG7i9Si+phGHn4cQ@mail.gmail.com>
2020-06-15 19:08     ` Andrii Nakryiko
2020-06-16  8:05       ` Hao Luo
2020-06-17  1:24         ` Hao Luo
2020-06-17  1:36           ` Andrii Nakryiko
2020-06-18  7:53             ` Hao Luo
2020-06-12 22:31 ` [RFC PATCH bpf-next 3/8] selftests/bpf: add __ksym extern selftest Andrii Nakryiko
     [not found]   ` <CA+khW7jxdS1KRpk2syVGjDqbyn3wAd3Eh_LEMAEhkPUehuXMwg@mail.gmail.com>
2020-06-15 19:11     ` Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 4/8] tools/bpftool: move map/prog parsing logic into common Andrii Nakryiko
2020-06-12 22:31 ` Andrii Nakryiko [this message]
2020-06-12 22:31 ` [RFC PATCH bpf-next 6/8] tools/bpftool: generalize BPF skeleton support and generate vmlinux.h Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 7/8] libbpf: wrap source argument of BPF_CORE_READ macro in parentheses Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 8/8] tools/bpftool: show PIDs with FDs open against BPF map/prog/link/btf Andrii Nakryiko
2020-06-13  3:45   ` Alexei Starovoitov
2020-06-13  5:57     ` Andrii Nakryiko
2020-06-13 22:14       ` Arnaldo Carvalho de Melo
2020-06-15  9:04         ` Toke Høiland-Jørgensen
2020-06-15  9:30           ` Quentin Monnet

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