tools/perf/util/perf-hooks.c

   1 /*
   2  * perf_hooks.c
   3  *
   4  * Copyright (C) 2016 Wang Nan <wangnan0@huawei.com>
   5  * Copyright (C) 2016 Huawei Inc.
   6  */
   7
   8 #include <errno.h>
   9 #include <stdlib.h>
  10 #include <setjmp.h>
  11 #include <linux/err.h>
  12 #include "util/util.h"
  13 #include "util/debug.h"
  14 #include "util/perf-hooks.h"
  15
  16 static sigjmp_buf jmpbuf;
  17 static const struct perf_hook_desc *current_perf_hook;
  18
  19 void perf_hooks__invoke(const struct perf_hook_desc *desc)
  20 {
  21         if (!(desc && desc->p_hook_func && *desc->p_hook_func))
  22                 return;
  23
  24         if (sigsetjmp(jmpbuf, 1)) {
  25                 pr_warning("Fatal error (SEGFAULT) in perf hook '%s'\n",
  26                            desc->hook_name);
  27                 *(current_perf_hook->p_hook_func) = NULL;
  28         } else {
  29                 current_perf_hook = desc;
  30                 (**desc->p_hook_func)(desc->hook_ctx);
  31         }
  32         current_perf_hook = NULL;
  33 }
  34
  35 void perf_hooks__recover(void)
  36 {
  37         if (current_perf_hook)
  38                 siglongjmp(jmpbuf, 1);
  39 }
  40
  41 #define PERF_HOOK(name)                                 \
  42 perf_hook_func_t __perf_hook_func_##name = NULL;        \
  43 struct perf_hook_desc __perf_hook_desc_##name =         \
  44         {.hook_name = #name,                            \
  45          .p_hook_func = &__perf_hook_func_##name,       \
  46          .hook_ctx = NULL};
  47 #include "perf-hooks-list.h"
  48 #undef PERF_HOOK
  49
  50 #define PERF_HOOK(name)         \
  51         &__perf_hook_desc_##name,
  52
  53 static struct perf_hook_desc *perf_hooks[] = {
  54 #include "perf-hooks-list.h"
  55 };
  56 #undef PERF_HOOK
  57
  58 int perf_hooks__set_hook(const char *hook_name,
  59                          perf_hook_func_t hook_func,
  60                          void *hook_ctx)
  61 {
  62         unsigned int i;
  63
  64         for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) {
  65                 if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0)
  66                         continue;
  67
  68                 if (*(perf_hooks[i]->p_hook_func))
  69                         pr_warning("Overwrite existing hook: %s\n", hook_name);
  70                 *(perf_hooks[i]->p_hook_func) = hook_func;
  71                 perf_hooks[i]->hook_ctx = hook_ctx;
  72                 return 0;
  73         }
  74         return -ENOENT;
  75 }
  76
  77 perf_hook_func_t perf_hooks__get_hook(const char *hook_name)
  78 {
  79         unsigned int i;
  80
  81         for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) {
  82                 if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0)
  83                         continue;
  84
  85                 return *(perf_hooks[i]->p_hook_func);
  86         }
  87         return ERR_PTR(-ENOENT);
  88 }