LXR linux/tools/testing/selftests/bpf/prog_tests/trace

   1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright (c) 2020, Oracle and/or its affiliates. */
   3
   4#include <test_progs.h>
   5
   6#include "trace_printk.skel.h"
   7
   8#define TRACEBUF        "/sys/kernel/debug/tracing/trace_pipe"
   9#define SEARCHMSG       "testing,testing"
  10
  11void test_trace_printk(void)
  12{
  13        int err, iter = 0, duration = 0, found = 0;
  14        struct trace_printk__bss *bss;
  15        struct trace_printk *skel;
  16        char *buf = NULL;
  17        FILE *fp = NULL;
  18        size_t buflen;
  19
  20        skel = trace_printk__open();
  21        if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
  22                return;
  23
  24        err = trace_printk__load(skel);
  25        if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
  26                goto cleanup;
  27
  28        bss = skel->bss;
  29
  30        err = trace_printk__attach(skel);
  31        if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
  32                goto cleanup;
  33
  34        fp = fopen(TRACEBUF, "r");
  35        if (CHECK(fp == NULL, "could not open trace buffer",
  36                  "error %d opening %s", errno, TRACEBUF))
  37                goto cleanup;
  38
  39        /* We do not want to wait forever if this test fails... */
  40        fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
  41
  42        /* wait for tracepoint to trigger */
  43        usleep(1);
  44        trace_printk__detach(skel);
  45
  46        if (CHECK(bss->trace_printk_ran == 0,
  47                  "bpf_trace_printk never ran",
  48                  "ran == %d", bss->trace_printk_ran))
  49                goto cleanup;
  50
  51        if (CHECK(bss->trace_printk_ret <= 0,
  52                  "bpf_trace_printk returned <= 0 value",
  53                  "got %d", bss->trace_printk_ret))
  54                goto cleanup;
  55
  56        /* verify our search string is in the trace buffer */
  57        while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
  58                if (strstr(buf, SEARCHMSG) != NULL)
  59                        found++;
  60                if (found == bss->trace_printk_ran)
  61                        break;
  62                if (++iter > 1000)
  63                        break;
  64        }
  65
  66        if (CHECK(!found, "message from bpf_trace_printk not found",
  67                  "no instance of %s in %s", SEARCHMSG, TRACEBUF))
  68                goto cleanup;
  69
  70cleanup:
  71        trace_printk__destroy(skel);
  72        free(buf);
  73        if (fp)
  74                fclose(fp);
  75}
  76