tools/testing/selftests/bpf/prog_tests/trace_printk.c

   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
  11 void 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
  70 cleanup:
  71         trace_printk__destroy(skel);
  72         free(buf);
  73         if (fp)
  74                 fclose(fp);
  75 }