Introduce BPF Program Snapshot helper (bps)

A simple program to list all bpf programs of a system.

[root@arch-fb-vm1 bcc]# ./build/introspection/bps -h
BPF Program Snapshot (bps):
List of all BPF programs loaded into the system.

Usage: bps [bpf-prog-id]
    [bpf-prog-id] If specified, it shows the details info of the bpf-prog

* List all bpf programs *
[root@arch-fb-vm1 bcc]# ./build/introspection/bps
      BID TYPE                 UID  #MAPS LoadTime     NAME
       82 kprobe                 0      1 Oct19/23:52  map_perf_test
       83 kprobe                 0      1 Oct19/23:52  map_perf_test
       84 kprobe                 0      1 Oct19/23:52  map_perf_test
       85 kprobe                 0      1 Oct19/23:52  map_perf_test
       86 kprobe                 0      4 Oct19/23:52  map_perf_test
       87 kprobe                 0      1 Oct19/23:52  map_perf_test
       88 kprobe                 0      1 Oct19/23:52  map_perf_test
       89 kprobe                 0      1 Oct19/23:52  map_perf_test

* List a particular bpf program *
[root@arch-fb-vm1 bcc]# ./build/introspection/bps 86
      BID TYPE                 UID  #MAPS LoadTime     NAME
       86 kprobe                 0      4 Oct19/23:52  map_perf_test

     MID TYPE            FLAGS         KeySz  ValueSz  MaxEnts NAME
     120 lru hash        0x0               4        8    10000 lru_hash_map
     129 lru hash        0x0               4        8       43 lru_hash_lookup
     123 array of maps   0x0               4        4     1024 array_of_lru_ha
     121 lru hash        0x2               4        8    10000 nocommon_lru_ha

* JIT disabled *
[root@arch-fb-vm1 bpf]# sysctl -w net.core.bpf_jit_enable=0
[root@arch-fb-vm1 bpf]# ./test_progs
[root@arch-fb-vm1 bcc]# ./build/introspection/bps
      BID TYPE                 UID  #MAPS LoadTime     NAME
      94- socket filter          0      1 Oct19/23:55  test_obj_id
      95- socket filter          0      1 Oct19/23:55  test_obj_id

* Run without CAP_SYS_ADMIN *
[kafai@arch-fb-vm1 ~]$ ./bps 1
Require CAP_SYS_ADMIN capability.  Please retry as root

* Older kernel *
[root@arch-fb-vm2 build]# uname -r
4.12.14
[root@arch-fb-vm2 build]# ./introspection/bps 1
Kernel does not support BPF introspection
Signed-off-by: Martin KaFai Lau <kafai@fb.com>

CMakeLists.txt

@@ -83,6 +83,7 @@ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall ${CXX_ISYSTEM_DIRS}")
 
 add_subdirectory(src)
+add_subdirectory(introspection)
 if(ENABLE_CLANG_JIT)
 add_subdirectory(examples)
 add_subdirectory(man)

SPECS/bcc+clang.spec

@@ -96,5 +96,6 @@ Command line tools for BPF Compiler Collection (BCC)
 %exclude /usr/share/bcc/examples/*/*/*.pyo
 
 %files -n bcc-tools
+/usr/share/bcc/introspection/*
 /usr/share/bcc/tools/*
 /usr/share/bcc/man/*

SPECS/bcc.spec

@@ -113,6 +113,7 @@ Command line tools for BPF Compiler Collection (BCC)
 %exclude /usr/share/bcc/examples/*/*/*.pyo
 
 %files -n bcc-tools
+/usr/share/bcc/introspection/*
 /usr/share/bcc/tools/*
 /usr/share/bcc/man/*
 

introspection/CMakeLists.txt

+# Copyright (c) Facebook, Inc.
+# Licensed under the Apache License, Version 2.0 (the "License")
+
+include_directories(${CMAKE_SOURCE_DIR}/src/cc)
+include_directories(${CMAKE_SOURCE_DIR}/src/cc/api)
+
+option(INSTALL_INTROSPECTION "Install BPF introspection tools" ON)
+
+add_executable(bps bps.c)
+target_link_libraries(bps bcc-static)
+
+install (TARGETS bps DESTINATION share/bcc/introspection)

introspection/bps.c

+#include <time.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <sysexits.h>
+
+#include "libbpf.h"
+
+static const char * const prog_type_strings[] = {
+  [BPF_PROG_TYPE_UNSPEC] = "unspec",
+  [BPF_PROG_TYPE_SOCKET_FILTER] = "socket filter",
+  [BPF_PROG_TYPE_KPROBE] = "kprobe",
+  [BPF_PROG_TYPE_SCHED_CLS] = "sched cls",
+  [BPF_PROG_TYPE_SCHED_ACT] = "sched act",
+  [BPF_PROG_TYPE_TRACEPOINT] = "tracepoint",
+  [BPF_PROG_TYPE_XDP] = "xdp",
+  [BPF_PROG_TYPE_PERF_EVENT] = "perf event",
+  [BPF_PROG_TYPE_CGROUP_SKB] = "cgroup skb",
+  [BPF_PROG_TYPE_CGROUP_SOCK] = "cgroup sock",
+  [BPF_PROG_TYPE_LWT_IN] = "lwt in",
+  [BPF_PROG_TYPE_LWT_OUT] = "lwt out",
+  [BPF_PROG_TYPE_LWT_XMIT] = "lwt xmit",
+  [BPF_PROG_TYPE_SOCK_OPS] = "sock ops",
+  [BPF_PROG_TYPE_SK_SKB] = "sk skb",
+};
+
+static const char * const map_type_strings[] = {
+  [BPF_MAP_TYPE_UNSPEC] = "unspec",
+  [BPF_MAP_TYPE_HASH] = "hash",
+  [BPF_MAP_TYPE_ARRAY] = "array",
+  [BPF_MAP_TYPE_PROG_ARRAY] = "prog array",
+  [BPF_MAP_TYPE_PERF_EVENT_ARRAY] = "perf-ev array",
+  [BPF_MAP_TYPE_PERCPU_HASH] = "percpu hash",
+  [BPF_MAP_TYPE_PERCPU_ARRAY] = "percpu array",
+  [BPF_MAP_TYPE_STACK_TRACE] = "stack trace",
+  [BPF_MAP_TYPE_CGROUP_ARRAY] = "cgroup array",
+  [BPF_MAP_TYPE_LRU_HASH] = "lru hash",
+  [BPF_MAP_TYPE_LRU_PERCPU_HASH] = "lru percpu hash",
+  [BPF_MAP_TYPE_LPM_TRIE] = "lpm trie",
+  [BPF_MAP_TYPE_ARRAY_OF_MAPS] = "array of maps",
+  [BPF_MAP_TYPE_HASH_OF_MAPS] = "hash of maps",
+  [BPF_MAP_TYPE_DEVMAP] = "devmap",
+  [BPF_MAP_TYPE_SOCKMAP] = "sockmap",
+};
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
+#define LAST_KNOWN_PROG_TYPE (ARRAY_SIZE(prog_type_strings) - 1)
+#define LAST_KNOWN_MAP_TYPE (ARRAY_SIZE(map_type_strings) - 1)
+#define min(x, y) ((x) < (y) ? (x) : (y))
+
+static inline uint64_t ptr_to_u64(const void *ptr)
+{
+  return (uint64_t) (unsigned long) ptr;
+}
+
+static inline void * u64_to_ptr(uint64_t ptr)
+{
+  return (void *) (unsigned long ) ptr;
+}
+
+static int handle_get_next_errno(int eno)
+{
+  switch (eno) {
+    case ENOENT:
+      return 0;
+    case EINVAL:
+      fprintf(stderr, "Kernel does not support BPF introspection\n");
+      return EX_UNAVAILABLE;
+    case EPERM:
+      fprintf(stderr,
+              "Require CAP_SYS_ADMIN capability.  Please retry as root\n");
+      return EX_NOPERM;
+    default:
+      fprintf(stderr, "%s\n", strerror(errno));
+      return 1;
+  }
+}
+
+static void print_prog_hdr(void)
+{
+  printf("%9s %-15s %8s %6s %-12s %-15s\n",
+         "BID", "TYPE", "UID", "#MAPS", "LoadTime", "NAME");
+}
+
+static void print_prog_info(const struct bpf_prog_info *prog_info)
+{
+  struct timespec real_time_ts, boot_time_ts;
+  time_t wallclock_load_time = 0;
+  char unknown_prog_type[16];
+  const char *prog_type;
+  char load_time[16];
+  struct tm load_tm;
+
+  if (prog_info->type > LAST_KNOWN_PROG_TYPE) {
+    snprintf(unknown_prog_type, sizeof(unknown_prog_type), "<%u>",
+             prog_info->type);
+    unknown_prog_type[sizeof(unknown_prog_type) - 1] = '\0';
+    prog_type = unknown_prog_type;
+  } else {
+    prog_type = prog_type_strings[prog_info->type];
+  }
+
+  if (!clock_gettime(CLOCK_REALTIME, &real_time_ts) &&
+      !clock_gettime(CLOCK_BOOTTIME, &boot_time_ts) &&
+      real_time_ts.tv_sec >= boot_time_ts.tv_sec)
+    wallclock_load_time =
+      (real_time_ts.tv_sec - boot_time_ts.tv_sec) +
+      prog_info->load_time / 1000000000;
+
+  if (wallclock_load_time && localtime_r(&wallclock_load_time, &load_tm))
+    strftime(load_time, sizeof(load_time), "%b%d/%H:%M", &load_tm);
+  else
+    snprintf(load_time, sizeof(load_time), "<%llu>",
+             prog_info->load_time / 1000000000);
+  load_time[sizeof(load_time) - 1] = '\0';
+
+  if (prog_info->jited_prog_len)
+    printf("%9u %-15s %8u %6u %-12s %-15s\n",
+           prog_info->id, prog_type, prog_info->created_by_uid,
+           prog_info->nr_map_ids, load_time, prog_info->name);
+  else
+    printf("%8u- %-15s %8u %6u %-12s %-15s\n",
+           prog_info->id, prog_type, prog_info->created_by_uid,
+           prog_info->nr_map_ids, load_time, prog_info->name);
+}
+
+static void print_map_hdr(void)
+{
+  printf("%8s %-15s %-10s %8s %8s %8s %-15s\n",
+         "MID", "TYPE", "FLAGS", "KeySz", "ValueSz", "MaxEnts",
+         "NAME");
+}
+
+static void print_map_info(const struct bpf_map_info *map_info)
+{
+  char unknown_map_type[16];
+  const char *map_type;
+
+  if (map_info->type > LAST_KNOWN_MAP_TYPE) {
+    snprintf(unknown_map_type, sizeof(unknown_map_type),
+             "<%u>", map_info->type);
+    unknown_map_type[sizeof(unknown_map_type) - 1] = '\0';
+    map_type = unknown_map_type;
+  } else {
+    map_type = map_type_strings[map_info->type];
+  }
+
+  printf("%8u %-15s 0x%-8x %8u %8u %8u %-15s\n",
+         map_info->id, map_type, map_info->map_flags, map_info->key_size,
+         map_info->value_size, map_info->max_entries,
+         map_info->name);
+}
+
+static int print_one_prog(uint32_t prog_id)
+{
+  const uint32_t usual_nr_map_ids = 64;
+  uint32_t nr_map_ids = usual_nr_map_ids;
+  struct bpf_prog_info prog_info;
+  uint32_t *map_ids =  NULL;
+  uint32_t info_len;
+  int ret = 0;
+  int prog_fd;
+  uint32_t i;
+
+  prog_fd = bpf_prog_get_fd_by_id(prog_id);
+  if (prog_fd == -1) {
+    if (errno == ENOENT) {
+      fprintf(stderr, "BID:%u not found\n", prog_id);
+      return EX_DATAERR;
+    } else {
+      return handle_get_next_errno(errno);
+    }
+  }
+
+  /* Retry at most one time for larger map_ids array */
+  for (i = 0; i < 2; i++) {
+    bzero(&prog_info, sizeof(prog_info));
+    prog_info.map_ids = ptr_to_u64(realloc(map_ids,
+                                           nr_map_ids * sizeof(*map_ids)));
+    if (!prog_info.map_ids) {
+      fprintf(stderr,
+              "Cannot allocate memory for %u map_ids for BID:%u\n",
+              nr_map_ids, prog_id);
+      close(prog_fd);
+      free(map_ids);
+      return 1;
+    }
+
+    map_ids = u64_to_ptr(prog_info.map_ids);
+    prog_info.nr_map_ids = nr_map_ids;
+    info_len = sizeof(prog_info);
+    ret = bpf_obj_get_info(prog_fd, &prog_info, &info_len);
+    if (ret) {
+      fprintf(stderr, "Cannot get info for BID:%u. %s(%d)\n",
+              prog_id, strerror(errno), errno);
+      close(prog_fd);
+      free(map_ids);
+      return ret;
+    }
+
+    if (prog_info.nr_map_ids <= nr_map_ids)
+      break;
+
+    nr_map_ids = prog_info.nr_map_ids;
+  }
+  close(prog_fd);
+
+  print_prog_hdr();
+  print_prog_info(&prog_info);
+  printf("\n");
+
+  /* Print all map_info used by the prog */
+  print_map_hdr();
+  nr_map_ids = min(prog_info.nr_map_ids, nr_map_ids);
+  for (i = 0; i < nr_map_ids; i++) {
+    struct bpf_map_info map_info = {};
+    uint32_t info_len = sizeof(map_info);
+    int map_fd;
+
+    map_fd = bpf_map_get_fd_by_id(map_ids[i]);
+    if (map_fd == -1) {
+      if (errno == -ENOENT)
+        continue;
+
+      fprintf(stderr,
+              "Cannot get fd for map:%u. %s(%d)\n",
+              map_ids[i], strerror(errno), errno);
+      ret = map_fd;
+      break;
+    }
+
+    ret = bpf_obj_get_info(map_fd, &map_info, &info_len);
+    close(map_fd);
+    if (ret) {
+      fprintf(stderr, "Cannot get info for map:%u. %s(%d)\n",
+              map_ids[i], strerror(errno), errno);
+      break;
+    }
+
+    print_map_info(&map_info);
+  }
+
+  free(map_ids);
+  return ret;
+}
+
+int print_all_progs(void)
+{
+  uint32_t next_id = 0;
+
+  print_prog_hdr();
+
+  while (!bpf_prog_get_next_id(next_id, &next_id)) {
+    struct bpf_prog_info prog_info = {};
+    uint32_t prog_info_len = sizeof(prog_info);
+    int prog_fd;
+    int ret;
+
+    prog_fd = bpf_prog_get_fd_by_id(next_id);
+    if (prog_fd < 0) {
+      if (errno == ENOENT)
+        continue;
+      fprintf(stderr,
+              "Cannot get fd for BID:%u. %s(%d)\n",
+              next_id, strerror(errno), errno);
+      return 1;
+    }
+
+    ret = bpf_obj_get_info(prog_fd, &prog_info, &prog_info_len);
+    close(prog_fd);
+    if (ret) {
+      fprintf(stderr,
+              "Cannot get bpf_prog_info for BID:%u. %s(%d)\n",
+              next_id, strerror(errno), errno);
+      return ret;
+    }
+
+    print_prog_info(&prog_info);
+  }
+
+  return handle_get_next_errno(errno);
+}
+
+void usage(void)
+{
+  printf("BPF Program Snapshot (bps):\n"
+         "List of all BPF programs loaded into the system.\n\n");
+  printf("Usage: bps [bpf-prog-id]\n");
+  printf("    [bpf-prog-id] If specified, it shows the details info of the bpf-prog\n");
+  printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+  if (argc > 1) {
+    if (!isdigit(*argv[1])) {
+      usage();
+      return EX_USAGE;
+    }
+    return print_one_prog((uint32_t)atoi(argv[1]));
+  }
+
+  return print_all_progs();
+}

tests/python/test_trace4.py

@@ -28,7 +28,8 @@ class TestKprobeRgx(TestCase):
     def test_send1(self):
         k1 = self.b["stats"].Key(1)
         k2 = self.b["stats"].Key(2)
-        self.assertEqual(self.b["stats"][k1].val, self.b["stats"][k2].val + 1)
+        self.assertTrue(self.b["stats"][k1].val >= 2)
+        self.assertTrue(self.b["stats"][k2].val == 1)
 
 class TestKprobeReplace(TestCase):
     def setUp(self):