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authorDaniel T. Lee <danieltimlee@gmail.com>2020-08-23 17:53:33 +0900
committerAlexei Starovoitov <ast@kernel.org>2020-08-24 20:59:35 -0700
commit3677d0a13171bb1dc8db0af84d48dea14a899962 (patch)
tree3de96b317e44d7e1eb175a4be093101f317e88ff /samples/bpf/spintest_user.c
parent35a8b6dd339f04cbcb0b2d085334263542a12b70 (diff)
downloadlinux-stericsson-3677d0a13171bb1dc8db0af84d48dea14a899962.tar.gz
samples: bpf: Refactor kprobe tracing programs with libbpf
For the problem of increasing fragmentation of the bpf loader programs, instead of using bpf_loader.o, which is used in samples/bpf, this commit refactors the existing kprobe tracing programs with libbbpf bpf loader. - For kprobe events pointing to system calls, the SYSCALL() macro in trace_common.h was used. - Adding a kprobe event and attaching a bpf program to it was done through bpf_program_attach(). - Instead of using the existing BPF MAP definition, MAP definition has been refactored with the new BTF-defined MAP format. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200823085334.9413-3-danieltimlee@gmail.com
Diffstat (limited to 'samples/bpf/spintest_user.c')
-rw-r--r--samples/bpf/spintest_user.c68
1 files changed, 55 insertions, 13 deletions
diff --git a/samples/bpf/spintest_user.c b/samples/bpf/spintest_user.c
index fb430ea2ef51..847da9284fa8 100644
--- a/samples/bpf/spintest_user.c
+++ b/samples/bpf/spintest_user.c
@@ -1,40 +1,77 @@
// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <unistd.h>
-#include <linux/bpf.h>
#include <string.h>
#include <assert.h>
#include <sys/resource.h>
#include <bpf/libbpf.h>
-#include "bpf_load.h"
+#include <bpf/bpf.h>
#include "trace_helpers.h"
int main(int ac, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ char filename[256], symbol[256];
+ struct bpf_object *obj = NULL;
+ struct bpf_link *links[20];
long key, next_key, value;
- char filename[256];
+ struct bpf_program *prog;
+ int map_fd, i, j = 0;
+ const char *title;
struct ksym *sym;
- int i;
- snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
- setrlimit(RLIMIT_MEMLOCK, &r);
+ if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+ perror("setrlimit(RLIMIT_MEMLOCK)");
+ return 1;
+ }
if (load_kallsyms()) {
printf("failed to process /proc/kallsyms\n");
return 2;
}
- if (load_bpf_file(filename)) {
- printf("%s", bpf_log_buf);
- return 1;
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+ obj = bpf_object__open_file(filename, NULL);
+ if (libbpf_get_error(obj)) {
+ fprintf(stderr, "ERROR: opening BPF object file failed\n");
+ obj = NULL;
+ goto cleanup;
+ }
+
+ /* load BPF program */
+ if (bpf_object__load(obj)) {
+ fprintf(stderr, "ERROR: loading BPF object file failed\n");
+ goto cleanup;
+ }
+
+ map_fd = bpf_object__find_map_fd_by_name(obj, "my_map");
+ if (map_fd < 0) {
+ fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+ goto cleanup;
+ }
+
+ bpf_object__for_each_program(prog, obj) {
+ title = bpf_program__title(prog, false);
+ if (sscanf(title, "kprobe/%s", symbol) != 1)
+ continue;
+
+ /* Attach prog only when symbol exists */
+ if (ksym_get_addr(symbol)) {
+ links[j] = bpf_program__attach(prog);
+ if (libbpf_get_error(links[j])) {
+ fprintf(stderr, "bpf_program__attach failed\n");
+ links[j] = NULL;
+ goto cleanup;
+ }
+ j++;
+ }
}
for (i = 0; i < 5; i++) {
key = 0;
printf("kprobing funcs:");
- while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
- bpf_map_lookup_elem(map_fd[0], &next_key, &value);
+ while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) {
+ bpf_map_lookup_elem(map_fd, &next_key, &value);
assert(next_key == value);
sym = ksym_search(value);
key = next_key;
@@ -48,10 +85,15 @@ int main(int ac, char **argv)
if (key)
printf("\n");
key = 0;
- while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0)
- bpf_map_delete_elem(map_fd[0], &next_key);
+ while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0)
+ bpf_map_delete_elem(map_fd, &next_key);
sleep(1);
}
+cleanup:
+ for (j--; j >= 0; j--)
+ bpf_link__destroy(links[j]);
+
+ bpf_object__close(obj);
return 0;
}