root/tools/perf/tests/sdt.c

DEFINITIONS

1. target_function
2. build_id_cache__add_file
3. get_self_path
4. search_cached_probe
5. test__sdt_event
6. test__sdt_event

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <limits.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <unistd.h>
   7 #include <sys/epoll.h>
   8 #include <util/symbol.h>
   9 #include <linux/filter.h>
  10 #include "tests.h"
  11 #include "debug.h"
  12 #include "probe-file.h"
  13 #include "build-id.h"
  14 #include "util.h"
  15 
  16 /* To test SDT event, we need libelf support to scan elf binary */
  17 #if defined(HAVE_SDT_EVENT) && defined(HAVE_LIBELF_SUPPORT)
  18 
  19 #include <sys/sdt.h>
  20 
  21 static int target_function(void)
  22 {
  23         DTRACE_PROBE(perf, test_target);
  24         return TEST_OK;
  25 }
  26 
  27 /* Copied from builtin-buildid-cache.c */
  28 static int build_id_cache__add_file(const char *filename)
  29 {
  30         char sbuild_id[SBUILD_ID_SIZE];
  31         u8 build_id[BUILD_ID_SIZE];
  32         int err;
  33 
  34         err = filename__read_build_id(filename, &build_id, sizeof(build_id));
  35         if (err < 0) {
  36                 pr_debug("Failed to read build id of %s\n", filename);
  37                 return err;
  38         }
  39 
  40         build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
  41         err = build_id_cache__add_s(sbuild_id, filename, NULL, false, false);
  42         if (err < 0)
  43                 pr_debug("Failed to add build id cache of %s\n", filename);
  44         return err;
  45 }
  46 
  47 static char *get_self_path(void)
  48 {
  49         char *buf = calloc(PATH_MAX, sizeof(char));
  50 
  51         if (buf && readlink("/proc/self/exe", buf, PATH_MAX - 1) < 0) {
  52                 pr_debug("Failed to get correct path of perf\n");
  53                 free(buf);
  54                 return NULL;
  55         }
  56         return buf;
  57 }
  58 
  59 static int search_cached_probe(const char *target,
  60                                const char *group, const char *event)
  61 {
  62         struct probe_cache *cache = probe_cache__new(target, NULL);
  63         int ret = 0;
  64 
  65         if (!cache) {
  66                 pr_debug("Failed to open probe cache of %s\n", target);
  67                 return -EINVAL;
  68         }
  69 
  70         if (!probe_cache__find_by_name(cache, group, event)) {
  71                 pr_debug("Failed to find %s:%s in the cache\n", group, event);
  72                 ret = -ENOENT;
  73         }
  74         probe_cache__delete(cache);
  75 
  76         return ret;
  77 }
  78 
  79 int test__sdt_event(struct test *test __maybe_unused, int subtests __maybe_unused)
  80 {
  81         int ret = TEST_FAIL;
  82         char __tempdir[] = "./test-buildid-XXXXXX";
  83         char *tempdir = NULL, *myself = get_self_path();
  84 
  85         if (myself == NULL || mkdtemp(__tempdir) == NULL) {
  86                 pr_debug("Failed to make a tempdir for build-id cache\n");
  87                 goto error;
  88         }
  89         /* Note that buildid_dir must be an absolute path */
  90         tempdir = realpath(__tempdir, NULL);
  91         if (tempdir == NULL)
  92                 goto error_rmdir;
  93 
  94         /* At first, scan itself */
  95         set_buildid_dir(tempdir);
  96         if (build_id_cache__add_file(myself) < 0)
  97                 goto error_rmdir;
  98 
  99         /* Open a cache and make sure the SDT is stored */
 100         if (search_cached_probe(myself, "sdt_perf", "test_target") < 0)
 101                 goto error_rmdir;
 102 
 103         /* TBD: probing on the SDT event and collect logs */
 104 
 105         /* Call the target and get an event */
 106         ret = target_function();
 107 
 108 error_rmdir:
 109         /* Cleanup temporary buildid dir */
 110         rm_rf(__tempdir);
 111 error:
 112         free(tempdir);
 113         free(myself);
 114         return ret;
 115 }
 116 #else
 117 int test__sdt_event(struct test *test __maybe_unused, int subtests __maybe_unused)
 118 {
 119         pr_debug("Skip SDT event test because SDT support is not compiled\n");
 120         return TEST_SKIP;
 121 }
 122 #endif