summaryrefslogtreecommitdiff
path: root/samples/bpf/bpf_load.c
diff options
context:
space:
mode:
Diffstat (limited to 'samples/bpf/bpf_load.c')
-rw-r--r--samples/bpf/bpf_load.c125
1 files changed, 117 insertions, 8 deletions
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 1831d236382b..38dac5a53b51 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -8,29 +8,70 @@
#include <unistd.h>
#include <string.h>
#include <stdbool.h>
+#include <stdlib.h>
#include <linux/bpf.h>
#include <linux/filter.h>
+#include <linux/perf_event.h>
+#include <sys/syscall.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <poll.h>
#include "libbpf.h"
#include "bpf_helpers.h"
#include "bpf_load.h"
+#define DEBUGFS "/sys/kernel/debug/tracing/"
+
static char license[128];
+static int kern_version;
static bool processed_sec[128];
int map_fd[MAX_MAPS];
int prog_fd[MAX_PROGS];
+int event_fd[MAX_PROGS];
int prog_cnt;
static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
{
- int fd;
bool is_socket = strncmp(event, "socket", 6) == 0;
-
- if (!is_socket)
- /* tracing events tbd */
+ bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
+ bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
+ enum bpf_prog_type prog_type;
+ char buf[256];
+ int fd, efd, err, id;
+ struct perf_event_attr attr = {};
+
+ attr.type = PERF_TYPE_TRACEPOINT;
+ attr.sample_type = PERF_SAMPLE_RAW;
+ attr.sample_period = 1;
+ attr.wakeup_events = 1;
+
+ if (is_socket) {
+ prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
+ } else if (is_kprobe || is_kretprobe) {
+ prog_type = BPF_PROG_TYPE_KPROBE;
+ } else {
+ printf("Unknown event '%s'\n", event);
return -1;
+ }
+
+ if (is_kprobe || is_kretprobe) {
+ if (is_kprobe)
+ event += 7;
+ else
+ event += 10;
+
+ snprintf(buf, sizeof(buf),
+ "echo '%c:%s %s' >> /sys/kernel/debug/tracing/kprobe_events",
+ is_kprobe ? 'p' : 'r', event, event);
+ err = system(buf);
+ if (err < 0) {
+ printf("failed to create kprobe '%s' error '%s'\n",
+ event, strerror(errno));
+ return -1;
+ }
+ }
- fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER,
- prog, size, license);
+ fd = bpf_prog_load(prog_type, prog, size, license, kern_version);
if (fd < 0) {
printf("bpf_prog_load() err=%d\n%s", errno, bpf_log_buf);
@@ -39,6 +80,41 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
prog_fd[prog_cnt++] = fd;
+ if (is_socket)
+ return 0;
+
+ strcpy(buf, DEBUGFS);
+ strcat(buf, "events/kprobes/");
+ strcat(buf, event);
+ strcat(buf, "/id");
+
+ efd = open(buf, O_RDONLY, 0);
+ if (efd < 0) {
+ printf("failed to open event %s\n", event);
+ return -1;
+ }
+
+ err = read(efd, buf, sizeof(buf));
+ if (err < 0 || err >= sizeof(buf)) {
+ printf("read from '%s' failed '%s'\n", event, strerror(errno));
+ return -1;
+ }
+
+ close(efd);
+
+ buf[err] = 0;
+ id = atoi(buf);
+ attr.config = id;
+
+ efd = perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
+ if (efd < 0) {
+ printf("event %d fd %d err %s\n", id, efd, strerror(errno));
+ return -1;
+ }
+ event_fd[prog_cnt - 1] = efd;
+ ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
+ ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
+
return 0;
}
@@ -135,6 +211,9 @@ int load_bpf_file(char *path)
if (gelf_getehdr(elf, &ehdr) != &ehdr)
return 1;
+ /* clear all kprobes */
+ i = system("echo \"\" > /sys/kernel/debug/tracing/kprobe_events");
+
/* scan over all elf sections to get license and map info */
for (i = 1; i < ehdr.e_shnum; i++) {
@@ -149,6 +228,14 @@ int load_bpf_file(char *path)
if (strcmp(shname, "license") == 0) {
processed_sec[i] = true;
memcpy(license, data->d_buf, data->d_size);
+ } else if (strcmp(shname, "version") == 0) {
+ processed_sec[i] = true;
+ if (data->d_size != sizeof(int)) {
+ printf("invalid size of version section %zd\n",
+ data->d_size);
+ return 1;
+ }
+ memcpy(&kern_version, data->d_buf, sizeof(int));
} else if (strcmp(shname, "maps") == 0) {
processed_sec[i] = true;
if (load_maps(data->d_buf, data->d_size))
@@ -178,7 +265,8 @@ int load_bpf_file(char *path)
if (parse_relo_and_apply(data, symbols, &shdr, insns))
continue;
- if (memcmp(shname_prog, "events/", 7) == 0 ||
+ if (memcmp(shname_prog, "kprobe/", 7) == 0 ||
+ memcmp(shname_prog, "kretprobe/", 10) == 0 ||
memcmp(shname_prog, "socket", 6) == 0)
load_and_attach(shname_prog, insns, data_prog->d_size);
}
@@ -193,7 +281,8 @@ int load_bpf_file(char *path)
if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
continue;
- if (memcmp(shname, "events/", 7) == 0 ||
+ if (memcmp(shname, "kprobe/", 7) == 0 ||
+ memcmp(shname, "kretprobe/", 10) == 0 ||
memcmp(shname, "socket", 6) == 0)
load_and_attach(shname, data->d_buf, data->d_size);
}
@@ -201,3 +290,23 @@ int load_bpf_file(char *path)
close(fd);
return 0;
}
+
+void read_trace_pipe(void)
+{
+ int trace_fd;
+
+ trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
+ if (trace_fd < 0)
+ return;
+
+ while (1) {
+ static char buf[4096];
+ ssize_t sz;
+
+ sz = read(trace_fd, buf, sizeof(buf));
+ if (sz > 0) {
+ buf[sz] = 0;
+ puts(buf);
+ }
+ }
+}