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Date: Wed, 1 Jul 2015 02:14:07 +0000
From: Wang Nan <wangnan0@...wei.com>
To: <acme@...nel.org>, <ast@...mgrid.com>, <brendan.d.gregg@...il.com>,
<daniel@...earbox.net>, <namhyung@...nel.org>,
<masami.hiramatsu.pt@...achi.com>, <paulus@...ba.org>,
<a.p.zijlstra@...llo.nl>, <mingo@...hat.com>, <jolsa@...nel.org>,
<dsahern@...il.com>
CC: <linux-kernel@...r.kernel.org>, <lizefan@...wei.com>,
<hekuang@...wei.com>, <xiakaixu@...wei.com>, <pi3orama@....com>
Subject: [RFC PATCH v10 19/50] bpf tools: Load eBPF programs in object files into kernel
This patch utilizes previous introduced bpf_load_program to load
programs in the ELF file into kernel. Result is stored in 'fd' field
in 'struct bpf_program'.
During loading, it allocs a log buffer and free it before return.
Note that that buffer is not passed to bpf_load_program() if the first
loading try is successful. Doesn't use a statically allocated log
buffer to avoid potention multi-thread problem.
Instructions collected during opening is cleared after loading.
load_program() is created for loading a 'struct bpf_insn' array into
kernel, bpf_program__load() calls it. By this design we have a function
loads instructions into kernel. It will be used by further patches,
which creates different instances from a program and load them into
kernel.
Signed-off-by: Wang Nan <wangnan0@...wei.com>
---
tools/lib/bpf/libbpf.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 90 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9d42774..33452f8 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -96,6 +96,8 @@ struct bpf_program {
int map_idx;
} *reloc_desc;
int nr_reloc;
+
+ int fd;
};
struct bpf_object {
@@ -135,11 +137,20 @@ struct bpf_object {
};
#define obj_elf_valid(o) ((o)->efile.elf)
+static void bpf_program__unload(struct bpf_program *prog)
+{
+ if (!prog)
+ return;
+
+ zclose(prog->fd);
+}
+
static void bpf_program__clear(struct bpf_program *prog)
{
if (!prog)
return;
+ bpf_program__unload(prog);
zfree(&prog->section_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
@@ -199,6 +210,7 @@ bpf_program__new(struct bpf_object *obj, void *data, size_t size,
memcpy(prog->insns, data,
prog->insns_cnt * sizeof(struct bpf_insn));
prog->idx = idx;
+ prog->fd = -1;
return prog;
out:
@@ -711,6 +723,79 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
return 0;
}
+static int
+load_program(struct bpf_insn *insns, int insns_cnt,
+ char *license, u32 kern_version, int *pfd)
+{
+ int ret;
+ char *log_buf;
+
+ if (!insns || !insns_cnt)
+ return -EINVAL;
+
+ log_buf = malloc(BPF_LOG_BUF_SIZE);
+ if (!log_buf)
+ pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
+
+ ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
+ insns_cnt, license, kern_version,
+ log_buf, BPF_LOG_BUF_SIZE);
+
+ if (ret >= 0) {
+ *pfd = ret;
+ ret = 0;
+ goto out;
+ }
+
+ ret = -EINVAL;
+ pr_warning("load bpf program failed: %s\n", strerror(errno));
+
+ if (log_buf) {
+ pr_warning("-- BEGIN DUMP LOG ---\n");
+ pr_warning("\n%s\n", log_buf);
+ pr_warning("-- END LOG --\n");
+ }
+
+out:
+ free(log_buf);
+ return ret;
+}
+
+static int
+bpf_program__load(struct bpf_program *prog,
+ char *license, u32 kern_version)
+{
+ int err, fd;
+
+ err = load_program(prog->insns, prog->insns_cnt,
+ license, kern_version, &fd);
+ if (!err)
+ prog->fd = fd;
+
+ if (err)
+ pr_warning("failed to load program '%s'\n",
+ prog->section_name);
+ zfree(&prog->insns);
+ prog->insns_cnt = 0;
+ return err;
+}
+
+static int
+bpf_object__load_progs(struct bpf_object *obj)
+{
+ size_t i;
+ int err;
+
+ for (i = 0; i < obj->nr_programs; i++) {
+ err = bpf_program__load(&obj->programs[i],
+ obj->license,
+ obj->kern_version);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
static int bpf_object__validate(struct bpf_object *obj)
{
if (obj->kern_version == 0) {
@@ -788,6 +873,9 @@ int bpf_object__unload(struct bpf_object *obj)
zfree(&obj->map_fds);
obj->nr_map_fds = 0;
+ for (i = 0; i < obj->nr_programs; i++)
+ bpf_program__unload(&obj->programs[i]);
+
return 0;
}
@@ -806,6 +894,8 @@ int bpf_object__load(struct bpf_object *obj)
goto out;
if (bpf_object__relocate(obj))
goto out;
+ if (bpf_object__load_progs(obj))
+ goto out;
return 0;
out:
--
1.8.3.4
--
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