Commit d40fc181 authored by Joe Stringer's avatar Joe Stringer Committed by Arnaldo Carvalho de Melo
Browse files

samples/bpf: Make samples more libbpf-centric 



Switch all of the sample code to use the function names from
tools/lib/bpf so that they're consistent with that, and to declare their
own log buffers. This allow the next commit to be purely devoted to
getting rid of the duplicate library in samples/bpf.

Committer notes:

Testing it:

On a fedora rawhide container, with clang/llvm 3.9, sharing the host
linux kernel git tree:

  # make O=/tmp/build/linux/ headers_install
  # make O=/tmp/build/linux -C samples/bpf/

Since I forgot to make it privileged, just tested it outside the
container, using what it generated:

  # uname -a
  Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
  # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/
  # ls -la offwaketime
  -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime
  # file offwaketime
  offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped
  # readelf -SW offwaketime_kern.o  | grep PROGBITS
  [ 2] .text             PROGBITS        0000000000000000 000040 000000 00  AX  0   0  4
  [ 3] kprobe/try_to_wake_up PROGBITS        0000000000000000 000040 0000d8 00  AX  0   0  8
  [ 5] tracepoint/sched/sched_switch PROGBITS        0000000000000000 000118 000318 00  AX  0   0  8
  [ 7] maps              PROGBITS        0000000000000000 000430 000050 00  WA  0   0  4
  [ 8] license           PROGBITS        0000000000000000 000480 000004 00  WA  0   0  1
  [ 9] version           PROGBITS        0000000000000000 000484 000004 00  WA  0   0  4
  # ./offwaketime | head -5
  swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106
  CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2
  Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5
  firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13
  JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2
  #

Signed-off-by: default avatarJoe Stringer <joe@ovn.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent a5580c7f

samples/bpf/bpf_load.c

+13 −4
Original line number Diff line number Diff line
@@ -22,7 +22,6 @@ 
#include <poll.h>

#include <ctype.h>

#include "libbpf.h"

#include "bpf_helpers.h"

#include "bpf_load.h"



#define DEBUGFS "/sys/kernel/debug/tracing/"
@@ -30,17 +29,26 @@ 
static char license[128];

static int kern_version;

static bool processed_sec[128];

char bpf_log_buf[BPF_LOG_BUF_SIZE];

int map_fd[MAX_MAPS];

int prog_fd[MAX_PROGS];

int event_fd[MAX_PROGS];

int prog_cnt;

int prog_array_fd = -1;



struct bpf_map_def {

	unsigned int type;

	unsigned int key_size;

	unsigned int value_size;

	unsigned int max_entries;

	unsigned int map_flags;

};



static int populate_prog_array(const char *event, int prog_fd)

{

	int ind = atoi(event), err;



	err = bpf_update_elem(prog_array_fd, &ind, &prog_fd, BPF_ANY);

	err = bpf_map_update_elem(prog_array_fd, &ind, &prog_fd, BPF_ANY);

	if (err < 0) {

		printf("failed to store prog_fd in prog_array\n");

		return -1;
@@ -87,9 +95,10 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) 
		return -1;

	}



	fd = bpf_prog_load(prog_type, prog, size, license, kern_version);

	fd = bpf_load_program(prog_type, prog, size, license, kern_version,

			      bpf_log_buf, BPF_LOG_BUF_SIZE);

	if (fd < 0) {

		printf("bpf_prog_load() err=%d\n%s", errno, bpf_log_buf);

		printf("bpf_load_program() err=%d\n%s", errno, bpf_log_buf);

		return -1;

	}

samples/bpf/bpf_load.h

+3 −0
Original line number Diff line number Diff line 
#ifndef __BPF_LOAD_H

#define __BPF_LOAD_H



#include "libbpf.h"



#define MAX_MAPS 32

#define MAX_PROGS 32



extern int map_fd[MAX_MAPS];

extern int prog_fd[MAX_PROGS];

extern int event_fd[MAX_PROGS];

extern char bpf_log_buf[BPF_LOG_BUF_SIZE];

extern int prog_cnt;



/* parses elf file compiled by llvm .c->.o

samples/bpf/fds_example.c

+5 −4
Original line number Diff line number Diff line
@@ -58,8 +58,9 @@ static int bpf_prog_create(const char *object) 
		assert(!load_bpf_file((char *)object));

		return prog_fd[0];

	} else {

		return bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER,

				     insns, sizeof(insns), "GPL", 0);

		return bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER,

					insns, sizeof(insns), "GPL", 0,

					bpf_log_buf, BPF_LOG_BUF_SIZE);

	}

}
@@ -83,12 +84,12 @@ static int bpf_do_map(const char *file, uint32_t flags, uint32_t key, 
	}



	if ((flags & BPF_F_KEY_VAL) == BPF_F_KEY_VAL) {

		ret = bpf_update_elem(fd, &key, &value, 0);

		ret = bpf_map_update_elem(fd, &key, &value, 0);

		printf("bpf: fd:%d u->(%u:%u) ret:(%d,%s)\n", fd, key, value,

		       ret, strerror(errno));

		assert(ret == 0);

	} else if (flags & BPF_F_KEY) {

		ret = bpf_lookup_elem(fd, &key, &value);

		ret = bpf_map_lookup_elem(fd, &key, &value);

		printf("bpf: fd:%d l->(%u):%u ret:(%d,%s)\n", fd, key, value,

		       ret, strerror(errno));

		assert(ret == 0);

samples/bpf/lathist_user.c

+1 −1
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ static void get_data(int fd) 
	for (c = 0; c < MAX_CPU; c++) {

		for (i = 0; i < MAX_ENTRIES; i++) {

			key = c * MAX_ENTRIES + i;

			bpf_lookup_elem(fd, &key, &value);

			bpf_map_lookup_elem(fd, &key, &value);



			cpu_hist[c].data[i] = value;

			if (value > cpu_hist[c].max)

samples/bpf/libbpf.c

+11 −12
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size, 
	return syscall(__NR_bpf, BPF_MAP_CREATE, &attr, sizeof(attr));

}



int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags)

int bpf_map_update_elem(int fd, void *key, void *value, unsigned long long flags)

{

	union bpf_attr attr = {

		.map_fd = fd,
@@ -44,7 +44,7 @@ int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags) 
	return syscall(__NR_bpf, BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));

}



int bpf_lookup_elem(int fd, void *key, void *value)

int bpf_map_lookup_elem(int fd, void *key, void *value)

{

	union bpf_attr attr = {

		.map_fd = fd,
@@ -55,7 +55,7 @@ int bpf_lookup_elem(int fd, void *key, void *value) 
	return syscall(__NR_bpf, BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));

}



int bpf_delete_elem(int fd, void *key)

int bpf_map_delete_elem(int fd, void *key)

{

	union bpf_attr attr = {

		.map_fd = fd,
@@ -65,7 +65,7 @@ int bpf_delete_elem(int fd, void *key) 
	return syscall(__NR_bpf, BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));

}



int bpf_get_next_key(int fd, void *key, void *next_key)

int bpf_map_get_next_key(int fd, void *key, void *next_key)

{

	union bpf_attr attr = {

		.map_fd = fd,
@@ -78,19 +78,18 @@ int bpf_get_next_key(int fd, void *key, void *next_key) 


#define ROUND_UP(x, n) (((x) + (n) - 1u) & ~((n) - 1u))



char bpf_log_buf[LOG_BUF_SIZE];



int bpf_prog_load(enum bpf_prog_type prog_type,

int bpf_load_program(enum bpf_prog_type prog_type,

		     const struct bpf_insn *insns, int prog_len,

		  const char *license, int kern_version)

		     const char *license, int kern_version,

		     char *log_buf, size_t log_buf_sz)

{

	union bpf_attr attr = {

		.prog_type = prog_type,

		.insns = ptr_to_u64((void *) insns),

		.insn_cnt = prog_len / sizeof(struct bpf_insn),

		.license = ptr_to_u64((void *) license),

		.log_buf = ptr_to_u64(bpf_log_buf),

		.log_size = LOG_BUF_SIZE,

		.log_buf = ptr_to_u64(log_buf),

		.log_size = log_buf_sz,

		.log_level = 1,

	};
@@ -99,7 +98,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type, 
	 */

	attr.kern_version = kern_version;



	bpf_log_buf[0] = 0;

	log_buf[0] = 0;



	return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));

}

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