src/lib/lttng-ust-common/ust-cancelstate.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2021 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  */
   6
   7 #include <pthread.h>
   8 #include <errno.h>
   9 #include <error.h>
  10 #include <urcu/tls-compat.h>
  11 #include <lttng/ust-cancelstate.h>
  12
  13 #include "common/logging.h"
  14
  15 struct ust_cancelstate {
  16         int nesting;
  17         int oldstate;   /* oldstate for outermost nesting */
  18 };
  19
  20 static DEFINE_URCU_TLS(struct ust_cancelstate, thread_state);
  21
  22 int lttng_ust_cancelstate_disable_push(void)
  23 {
  24         struct ust_cancelstate *state = &URCU_TLS(thread_state);
  25         int ret, oldstate;
  26
  27         if (state->nesting++)
  28                 goto end;
  29         ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
  30         if (ret) {
  31                 ERR("pthread_setcancelstate: %s", strerror(ret));
  32                 return -1;
  33         }
  34         state->oldstate = oldstate;
  35 end:
  36         return 0;
  37 }
  38
  39 int lttng_ust_cancelstate_disable_pop(void)
  40 {
  41         struct ust_cancelstate *state = &URCU_TLS(thread_state);
  42         int ret, oldstate;
  43
  44         if (!state->nesting)
  45                 return -1;
  46         if (--state->nesting)
  47                 goto end;
  48         ret = pthread_setcancelstate(state->oldstate, &oldstate);
  49         if (ret) {
  50                 ERR("pthread_setcancelstate: %s", strerror(ret));
  51                 return -1;
  52         }
  53         if (oldstate != PTHREAD_CANCEL_DISABLE) {
  54                 ERR("pthread_setcancelstate: unexpected oldstate");
  55                 return -1;
  56         }
  57 end:
  58         return 0;
  59 }
  60
  61