我写了一个简单的程序附加到execve
使用 kprobe 进行系统调用,但我看不到相关输出。
这是我的 one.c(BPF 程序):
#include <errno.h>
#include <bpf/bpf.h>
#include <stdio.h>
#include <string.h>
#include "bpf_load.h"
#include "bpf_util.h"
#include "libbpf.h"
#define SEC(NAME) __attribute__((section(NAME), used))
SEC("kprobe/execve")
int bpf_prog1(struct pt_regs *ctx)
{
char m[]="hello world";
bpf_trace_printk(m,sizeof(m));
return 0;
}
char _license[] SEC("license") = "GPL";
bpf_load.c(用户空间加载器):
#include "bpf_load.h"
#include <stdio.h>
#include <linux/bpf.h>
#include <sys/resource.h>
int main(int argc, char **argv) {
if (load_bpf_file("one.o")) {
printf("%s", bpf_log_buf);
return 1;
}
return 0;
}
和生成文件:
CLANG = clang
EXECABLE = monitor-exec
BPFCODE = one
BPFTOOLS = /kernel-src/samples/bpf
BPFLOADER = $(BPFTOOLS)/bpf_load.c
INCLUDE += -I/kernel-src/samples/bpf
INCLUDE += -I/kernel-src/tools/lib
CCINCLUDE += -I/kernel-src/tools/testing/selftests/bpf
CCINCLUDE += -I/kernel-src/tools/lib/bpf
CCINCLUDE += ${INCLUDE}
LOADINCLUDE += -I/kernel-src/tools/include
LOADINCLUDE += -I/kernel-src/tools/perf
LOADINCLUDE += ${INCLUDE}
LIBRARY_PATH = -L/usr/local/lib64
BPFSO = -lbpf
.PHONY: clean bpfload build
clean:
rm -f *.o *.so $(EXECABLE)
build: ${BPFCODE.c} ${BPFLOADER}
$(CLANG) -O2 -DHAVE_ATTR_TEST=0 -target bpf -c $(BPFCODE:=.c) $(CCINCLUDE) -o ${BPFCODE:=.o}
bpfload: build
clang -o $(EXECABLE) -DHAVE_ATTR_TEST=0 -lelf $(LOADINCLUDE) $(LIBRARY_PATH) $(BPFSO) \
$(BPFLOADER) loader.c
$(EXECABLE): bpfload
.DEFAULT_GOAL := $(EXECABLE)
到目前为止,我没有从 Makefile 中收到任何错误。
当我执行时,我得到以下输出./monitor-exec
invalid relo for insn[6].code 0x85
bpf_load_program() err=22
last insn is not an exit or jmp
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
last insn is not an exit or jmp
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
我无法理解我做错了什么。我只是附加一个 kprobe 并且应该打印hello world
当该系统调用发生时。