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 <linux/kernel.h>
  13 #include "util/util.h"
  14 #include "util/debug.h"
  15 #include "util/perf-hooks.h"
  16
  17 static sigjmp_buf jmpbuf;
  18 static const struct perf_hook_desc *current_perf_hook;
  19
  20 void perf_hooks__invoke(const struct perf_hook_desc *desc)
  21 {
  22         if (!(desc && desc->p_hook_func && *desc->p_hook_func))
  23                 return;
  24
  25         if (sigsetjmp(jmpbuf, 1)) {
  26                 pr_warning("Fatal error (SEGFAULT) in perf hook '%s'\n",
  27                            desc->hook_name);
  28                 *(current_perf_hook->p_hook_func) = NULL;
  29         } else {
  30                 current_perf_hook = desc;
  31                 (**desc->p_hook_func)(desc->hook_ctx);
  32         }
  33         current_perf_hook = NULL;
  34 }
  35
  36 void perf_hooks__recover(void)
  37 {
  38         if (current_perf_hook)
  39                 siglongjmp(jmpbuf, 1);
  40 }
  41
  42 #define PERF_HOOK(name)                                 \
  43 perf_hook_func_t __perf_hook_func_##name = NULL;        \
  44 struct perf_hook_desc __perf_hook_desc_##name =         \
  45         {.hook_name = #name,                            \
  46          .p_hook_func = &__perf_hook_func_##name,       \
  47          .hook_ctx = NULL};
  48 #include "perf-hooks-list.h"
  49 #undef PERF_HOOK
  50
  51 #define PERF_HOOK(name)         \
  52         &__perf_hook_desc_##name,
  53
  54 static struct perf_hook_desc *perf_hooks[] = {
  55 #include "perf-hooks-list.h"
  56 };
  57 #undef PERF_HOOK
  58
  59 int perf_hooks__set_hook(const char *hook_name,
  60                          perf_hook_func_t hook_func,
  61                          void *hook_ctx)
  62 {
  63         unsigned int i;
  64
  65         for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) {
  66                 if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0)
  67                         continue;
  68
  69                 if (*(perf_hooks[i]->p_hook_func))
  70                         pr_warning("Overwrite existing hook: %s\n", hook_name);
  71                 *(perf_hooks[i]->p_hook_func) = hook_func;
  72                 perf_hooks[i]->hook_ctx = hook_ctx;
  73                 return 0;
  74         }
  75         return -ENOENT;
  76 }
  77
  78 perf_hook_func_t perf_hooks__get_hook(const char *hook_name)
  79 {
  80         unsigned int i;
  81
  82         for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) {
  83                 if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0)
  84                         continue;
  85
  86                 return *(perf_hooks[i]->p_hook_func);
  87         }
  88         return ERR_PTR(-ENOENT);
  89 }