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Message-Id: <1438959032-8637-11-git-send-email-acme@kernel.org>
Date: Fri, 7 Aug 2015 11:50:18 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org, Wang Nan <wangnan0@...wei.com>,
Brendan Gregg <brendan.d.gregg@...il.com>,
Daniel Borkmann <daniel@...earbox.net>,
David Ahern <dsahern@...il.com>, He Kuang <hekuang@...wei.com>,
Jiri Olsa <jolsa@...nel.org>, Kaixu Xia <xiakaixu@...wei.com>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Namhyung Kim <namhyung@...nel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Zefan Li <lizefan@...wei.com>, pi3orama@....com,
Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 10/24] bpf tools: Collect eBPF programs from their own sections
From: Wang Nan <wangnan0@...wei.com>
This patch collects all programs in an object file into an array of
'struct bpf_program' for further processing. That structure is for
representing each eBPF program. 'bpf_prog' should be a better name, but
it has been used by linux/filter.h. Although it is a kernel space name,
I still prefer to call it 'bpf_program' to prevent possible confusion.
bpf_object__add_program() creates a new 'struct bpf_program' object.
It first init a variable in stack using bpf_program__init(), then if
success, enlarges obj->programs array and copy the new object in.
Signed-off-by: Wang Nan <wangnan0@...wei.com>
Acked-by: Alexei Starovoitov <ast@...mgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: David Ahern <dsahern@...il.com>
Cc: He Kuang <hekuang@...wei.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Kaixu Xia <xiakaixu@...wei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Zefan Li <lizefan@...wei.com>
Cc: pi3orama@....com
Link: http://lkml.kernel.org/r/1435716878-189507-13-git-send-email-wangnan0@huawei.com
[ Made bpf_object__add_program() propagate the error (-EINVAL or -ENOMEM) ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
tools/lib/bpf/libbpf.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 114 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9b016c086867..102156f322b6 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -78,12 +78,27 @@ void libbpf_set_print(libbpf_print_fn_t warn,
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
#endif
+/*
+ * bpf_prog should be a better name but it has been used in
+ * linux/filter.h.
+ */
+struct bpf_program {
+ /* Index in elf obj file, for relocation use. */
+ int idx;
+ char *section_name;
+ struct bpf_insn *insns;
+ size_t insns_cnt;
+};
+
struct bpf_object {
char license[64];
u32 kern_version;
void *maps_buf;
size_t maps_buf_sz;
+ struct bpf_program *programs;
+ size_t nr_programs;
+
/*
* Information when doing elf related work. Only valid if fd
* is valid.
@@ -100,6 +115,85 @@ struct bpf_object {
};
#define obj_elf_valid(o) ((o)->efile.elf)
+static void bpf_program__exit(struct bpf_program *prog)
+{
+ if (!prog)
+ return;
+
+ zfree(&prog->section_name);
+ zfree(&prog->insns);
+ prog->insns_cnt = 0;
+ prog->idx = -1;
+}
+
+static int
+bpf_program__init(void *data, size_t size, char *name, int idx,
+ struct bpf_program *prog)
+{
+ if (size < sizeof(struct bpf_insn)) {
+ pr_warning("corrupted section '%s'\n", name);
+ return -EINVAL;
+ }
+
+ bzero(prog, sizeof(*prog));
+
+ prog->section_name = strdup(name);
+ if (!prog->section_name) {
+ pr_warning("failed to alloc name for prog %s\n",
+ name);
+ goto errout;
+ }
+
+ prog->insns = malloc(size);
+ if (!prog->insns) {
+ pr_warning("failed to alloc insns for %s\n", name);
+ goto errout;
+ }
+ prog->insns_cnt = size / sizeof(struct bpf_insn);
+ memcpy(prog->insns, data,
+ prog->insns_cnt * sizeof(struct bpf_insn));
+ prog->idx = idx;
+
+ return 0;
+errout:
+ bpf_program__exit(prog);
+ return -ENOMEM;
+}
+
+static int
+bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
+ char *name, int idx)
+{
+ struct bpf_program prog, *progs;
+ int nr_progs, err;
+
+ err = bpf_program__init(data, size, name, idx, &prog);
+ if (err)
+ return err;
+
+ progs = obj->programs;
+ nr_progs = obj->nr_programs;
+
+ progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
+ if (!progs) {
+ /*
+ * In this case the original obj->programs
+ * is still valid, so don't need special treat for
+ * bpf_close_object().
+ */
+ pr_warning("failed to alloc a new program '%s'\n",
+ name);
+ bpf_program__exit(&prog);
+ return -ENOMEM;
+ }
+
+ pr_debug("found program %s\n", prog.section_name);
+ obj->programs = progs;
+ obj->nr_programs = nr_progs + 1;
+ progs[nr_progs] = prog;
+ return 0;
+}
+
static struct bpf_object *bpf_object__new(const char *path,
void *obj_buf,
size_t obj_buf_sz)
@@ -342,6 +436,17 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
err = -EEXIST;
} else
obj->efile.symbols = data;
+ } else if ((sh.sh_type == SHT_PROGBITS) &&
+ (sh.sh_flags & SHF_EXECINSTR) &&
+ (data->d_size > 0)) {
+ err = bpf_object__add_program(obj, data->d_buf,
+ data->d_size, name, idx);
+ if (err) {
+ char errmsg[128];
+ strerror_r(-err, errmsg, sizeof(errmsg));
+ pr_warning("failed to alloc program %s (%s): %s",
+ name, obj->path, errmsg);
+ }
}
if (err)
goto out;
@@ -415,11 +520,20 @@ struct bpf_object *bpf_object__open_buffer(void *obj_buf,
void bpf_object__close(struct bpf_object *obj)
{
+ size_t i;
+
if (!obj)
return;
bpf_object__elf_finish(obj);
zfree(&obj->maps_buf);
+
+ if (obj->programs && obj->nr_programs) {
+ for (i = 0; i < obj->nr_programs; i++)
+ bpf_program__exit(&obj->programs[i]);
+ }
+ zfree(&obj->programs);
+
free(obj);
}
--
2.1.0
--
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