From 3677d0a13171bb1dc8db0af84d48dea14a899962 Mon Sep 17 00:00:00 2001 From: "Daniel T. Lee" Date: Sun, 23 Aug 2020 17:53:33 +0900 Subject: 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 Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200823085334.9413-3-danieltimlee@gmail.com --- samples/bpf/test_probe_write_user_user.c | 49 +++++++++++++++++++++++++------- 1 file changed, 39 insertions(+), 10 deletions(-) (limited to 'samples/bpf/test_probe_write_user_user.c') diff --git a/samples/bpf/test_probe_write_user_user.c b/samples/bpf/test_probe_write_user_user.c index 045eb5e30f54..00ccfb834e45 100644 --- a/samples/bpf/test_probe_write_user_user.c +++ b/samples/bpf/test_probe_write_user_user.c @@ -1,21 +1,22 @@ // SPDX-License-Identifier: GPL-2.0 #include #include -#include #include #include -#include "bpf_load.h" +#include #include -#include #include #include int main(int ac, char **argv) { - int serverfd, serverconnfd, clientfd; - socklen_t sockaddr_len; - struct sockaddr serv_addr, mapped_addr, tmp_addr; struct sockaddr_in *serv_addr_in, *mapped_addr_in, *tmp_addr_in; + struct sockaddr serv_addr, mapped_addr, tmp_addr; + int serverfd, serverconnfd, clientfd, map_fd; + struct bpf_link *link = NULL; + struct bpf_program *prog; + struct bpf_object *obj; + socklen_t sockaddr_len; char filename[256]; char *ip; @@ -24,10 +25,35 @@ int main(int ac, char **argv) tmp_addr_in = (struct sockaddr_in *)&tmp_addr; 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"); + return 0; + } + + prog = bpf_object__find_program_by_name(obj, "bpf_prog1"); + if (libbpf_get_error(prog)) { + fprintf(stderr, "ERROR: finding a prog in obj file failed\n"); + 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, "dnat_map"); + if (map_fd < 0) { + fprintf(stderr, "ERROR: finding a map in obj file failed\n"); + goto cleanup; + } - if (load_bpf_file(filename)) { - printf("%s", bpf_log_buf); - return 1; + link = bpf_program__attach(prog); + if (libbpf_get_error(link)) { + fprintf(stderr, "ERROR: bpf_program__attach failed\n"); + link = NULL; + goto cleanup; } assert((serverfd = socket(AF_INET, SOCK_STREAM, 0)) > 0); @@ -51,7 +77,7 @@ int main(int ac, char **argv) mapped_addr_in->sin_port = htons(5555); mapped_addr_in->sin_addr.s_addr = inet_addr("255.255.255.255"); - assert(!bpf_map_update_elem(map_fd[0], &mapped_addr, &serv_addr, BPF_ANY)); + assert(!bpf_map_update_elem(map_fd, &mapped_addr, &serv_addr, BPF_ANY)); assert(listen(serverfd, 5) == 0); @@ -75,5 +101,8 @@ int main(int ac, char **argv) /* Is the server's getsockname = the socket getpeername */ assert(memcmp(&serv_addr, &tmp_addr, sizeof(struct sockaddr_in)) == 0); +cleanup: + bpf_link__destroy(link); + bpf_object__close(obj); return 0; } -- cgit v1.2.3