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[PATCH v11 20/39] bpf tools: Introduce accessors for struct bpf_program

From Wang Nan <wangnan0@huawei.com>
Newsgroups linux.kernel
Subject [PATCH v11 20/39] bpf tools: Introduce accessors for struct bpf_program
Date 2015-07-08 15:30 +0200
Message-ID <pJXAg-3fG-61@gated-at.bofh.it> (permalink)
References <pJXqx-3bZ-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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This patch introduces accessors for user of libbpf to retrieve section
name and fd of a opened/loaded eBPF program. 'struct bpf_prog_handler'
is used for that purpose. Accessors of programs section name and file
descriptor are provided. Set/get private data are also impelmented.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: acme@kernel.org
Link: http://lkml.kernel.org/r/1435716878-189507-21-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/libbpf.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tools/lib/bpf/libbpf.h | 25 +++++++++++++++
 2 files changed, 107 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d826d5b..b1575c4 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -98,6 +98,10 @@ struct bpf_program {
 	int nr_reloc;
 
 	int fd;
+
+	struct bpf_object *obj;
+	void *priv;
+	bpf_program_clear_priv_t clear_priv;
 };
 
 struct bpf_object {
@@ -150,6 +154,12 @@ static void bpf_program__clear(struct bpf_program *prog)
 	if (!prog)
 		return;
 
+	if (prog->clear_priv)
+		prog->clear_priv(prog, prog->priv);
+
+	prog->priv = NULL;
+	prog->clear_priv = NULL;
+
 	bpf_program__unload(prog);
 	zfree(&prog->section_name);
 	zfree(&prog->insns);
@@ -224,6 +234,7 @@ bpf_program__new(struct bpf_object *obj, void *data, size_t size,
 
 	obj->programs = progs;
 	obj->nr_programs = nr_progs + 1;
+	prog.obj = obj;
 	progs[nr_progs] = prog;
 	return &progs[nr_progs];
 }
@@ -934,3 +945,74 @@ void bpf_object__close(struct bpf_object *obj)
 
 	free(obj);
 }
+
+struct bpf_program *
+bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
+{
+	size_t idx;
+
+	if (!obj->programs)
+		return NULL;
+	/* First handler */
+	if (prev == NULL)
+		return &obj->programs[0];
+
+	if (prev->obj != obj) {
+		pr_warning("error: program handler doesn't match object\n");
+		return NULL;
+	}
+
+	idx = (prev - obj->programs) + 1;
+	if (idx >= obj->nr_programs)
+		return NULL;
+	return &obj->programs[idx];
+}
+
+int bpf_program__set_private(struct bpf_program *prog,
+			     void *priv,
+			     bpf_program_clear_priv_t clear_priv)
+{
+	if (prog->priv && prog->clear_priv)
+		prog->clear_priv(prog, prog->priv);
+
+	prog->priv = priv;
+	prog->clear_priv = clear_priv;
+	return 0;
+}
+
+int bpf_program__get_private(struct bpf_program *prog, void **ppriv)
+{
+	*ppriv = prog->priv;
+	return 0;
+}
+
+int bpf_program__get_title(struct bpf_program *prog,
+			   const char **ptitle, bool dup)
+{
+	const char *title;
+
+	if (!ptitle)
+		return -EINVAL;
+
+	title = prog->section_name;
+	if (dup) {
+		title = strdup(title);
+		if (!title) {
+			pr_warning("failed to strdup program title\n");
+			*ptitle = NULL;
+			return -ENOMEM;
+		}
+	}
+
+	*ptitle = title;
+	return 0;
+}
+
+int bpf_program__get_fd(struct bpf_program *prog, int *pfd)
+{
+	if (!pfd)
+		return -EINVAL;
+
+	*pfd = prog->fd;
+	return 0;
+}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 3e69600..9e0e102 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -9,6 +9,7 @@
 #define __BPF_LIBBPF_H
 
 #include <stdio.h>
+#include <stdbool.h>
 
 /*
  * In include/linux/compiler-gcc.h, __printf is defined. However
@@ -34,6 +35,30 @@ void bpf_object__close(struct bpf_object *object);
 int bpf_object__load(struct bpf_object *obj);
 int bpf_object__unload(struct bpf_object *obj);
 
+/* Accessors of bpf_program. */
+struct bpf_program;
+struct bpf_program *bpf_program__next(struct bpf_program *prog,
+				      struct bpf_object *obj);
+
+#define bpf_object__for_each_program(pos, obj)		\
+	for ((pos) = bpf_program__next(NULL, (obj));	\
+	     (pos) != NULL;				\
+	     (pos) = bpf_program__next((pos), (obj)))
+
+typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
+					 void *);
+
+int bpf_program__set_private(struct bpf_program *prog, void *priv,
+			     bpf_program_clear_priv_t clear_priv);
+
+int bpf_program__get_private(struct bpf_program *prog,
+			     void **ppriv);
+
+int bpf_program__get_title(struct bpf_program *prog,
+			   const char **ptitle, bool dup);
+
+int bpf_program__get_fd(struct bpf_program *prog, int *pfd);
+
 /*
  * We don't need __attribute__((packed)) now since it is
  * unnecessary for 'bpf_map_def' because they are all aligned.
-- 
1.8.3.4

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Thread

[PATCH v11 00/39] perf tools: filtering events using eBPF programs - part1 Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 03/39] bpf tools: Introduce 'bpf' library and add bpf feature check Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 35/39] perf tools: Add bpf_fd field to evsel and config it Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 28/39] perf tools: Make perf depend on libbpf Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 34/39] perf record: Load all eBPF object into kernel Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 13/39] bpf tools: Collect relocation sections from SHT_REL sections Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 22/39] bpf tools: Link all bpf objects onto a list Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 02/39] tracing, perf: Implement BPF programs attached to uprobes Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 07/39] bpf tools: Check endianness and make libbpf fail early Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 38/39] perf record: Add clang options for compiling BPF scripts Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 33/39] perf record: Probe at kprobe points Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 32/39] perf probe: Attach trace_probe_event with perf_probe_event Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 36/39] perf tools: Attach eBPF program to perf event Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 23/39] perf tools: Introduce llvm config options Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 11/39] bpf tools: Collect symbol table from SHT_SYMTAB section Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 10/39] bpf tools: Collect map definitions from 'maps' section Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:20 +0200
  [PATCH v11 19/39] bpf tools: Load eBPF programs in object files into kernel Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 18/39] bpf tools: Introduce bpf_load_program() to bpf.c Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 15/39] bpf tools: Add bpf.c/h for common bpf operations Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 29/39] perf record: Enable passing bpf object file to --event Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 05/39] bpf tools: Open eBPF object file and do basic validation Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 27/39] perf tests: Add LLVM test for eBPF on-the-fly compiling Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 09/39] bpf tools: Collect version and license from ELF sections Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 31/39] perf tools: Parse probe points of eBPF programs during preparation Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 17/39] bpf tools: Relocate eBPF programs Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 16/39] bpf tools: Create eBPF maps defined in an object file Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 14/39] bpf tools: Record map accessing instructions for each program Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 25/39] perf tools: Auto detecting kernel build directory Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 39/39] bpf tools: Load a program with different instance using preprocessor Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 04/39] bpf tools: Allow caller to set printing function Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 21/39] bpf tools: Introduce accessors for struct bpf_object Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 06/39] bpf tools: Read eBPF object from buffer Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 24/39] perf tools: Call clang to compile C source to object code Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 20/39] bpf tools: Introduce accessors for struct bpf_program Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 37/39] perf tools: Suppress probing messages when probing by BPF loading Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  [PATCH v11 26/39] perf tools: Auto detecting kernel include options Wang Nan <wangnan0@huawei.com> - 2015-07-08 15:30 +0200
  Re: [PATCH v11 00/39] perf tools: filtering events using eBPF  programs - part1 Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-08 16:10 +0200

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