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kernel/linux-rt-4.4.41/tools/lib/bpf/bpf.c 1.93 KB
5113f6f70   김현기   kernel add
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  /*
   * common eBPF ELF operations.
   *
   * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
   * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
   * Copyright (C) 2015 Huawei Inc.
   */
  
  #include <stdlib.h>
  #include <memory.h>
  #include <unistd.h>
  #include <asm/unistd.h>
  #include <linux/bpf.h>
  #include "bpf.h"
  
  /*
   * When building perf, unistd.h is override. Define __NR_bpf is
   * required to be defined.
   */
  #ifndef __NR_bpf
  # if defined(__i386__)
  #  define __NR_bpf 357
  # elif defined(__x86_64__)
  #  define __NR_bpf 321
  # elif defined(__aarch64__)
  #  define __NR_bpf 280
  # else
  #  error __NR_bpf not defined. libbpf does not support your arch.
  # endif
  #endif
  
  static __u64 ptr_to_u64(void *ptr)
  {
  	return (__u64) (unsigned long) ptr;
  }
  
  static int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
  		   unsigned int size)
  {
  	return syscall(__NR_bpf, cmd, attr, size);
  }
  
  int bpf_create_map(enum bpf_map_type map_type, int key_size,
  		   int value_size, int max_entries)
  {
  	union bpf_attr attr;
  
  	memset(&attr, '\0', sizeof(attr));
  
  	attr.map_type = map_type;
  	attr.key_size = key_size;
  	attr.value_size = value_size;
  	attr.max_entries = max_entries;
  
  	return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
  }
  
  int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
  		     size_t insns_cnt, char *license,
  		     u32 kern_version, char *log_buf, size_t log_buf_sz)
  {
  	int fd;
  	union bpf_attr attr;
  
  	bzero(&attr, sizeof(attr));
  	attr.prog_type = type;
  	attr.insn_cnt = (__u32)insns_cnt;
  	attr.insns = ptr_to_u64(insns);
  	attr.license = ptr_to_u64(license);
  	attr.log_buf = ptr_to_u64(NULL);
  	attr.log_size = 0;
  	attr.log_level = 0;
  	attr.kern_version = kern_version;
  
  	fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
  	if (fd >= 0 || !log_buf || !log_buf_sz)
  		return fd;
  
  	/* Try again with log */
  	attr.log_buf = ptr_to_u64(log_buf);
  	attr.log_size = log_buf_sz;
  	attr.log_level = 1;
  	log_buf[0] = 0;
  	return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
  }