granicus.if.org Git - strace/blob - delay.c

   1 /*
   2  * Copyright (c) 2018 The strace developers.
   3  * All rights reserved.
   4  *
   5  * SPDX-License-Identifier: LGPL-2.1-or-later
   6  */
   7
   8 #include "defs.h"
   9
  10 struct inject_delay_data {
  11         struct timespec ts_enter;
  12         struct timespec ts_exit;
  13 };
  14
  15 static struct inject_delay_data *delay_data_vec;
  16 static size_t delay_data_vec_capacity; /* size of the arena */
  17 static size_t delay_data_vec_size;     /* size of the used arena */
  18
  19 static timer_t delay_timer = (timer_t) -1;
  20 static bool delay_timer_is_armed;
  21
  22 static void
  23 expand_delay_data_vec(void)
  24 {
  25         const size_t old_capacity = delay_data_vec_capacity;
  26         delay_data_vec = xgrowarray(delay_data_vec, &delay_data_vec_capacity,
  27                                     sizeof(*delay_data_vec));
  28         memset(delay_data_vec + old_capacity, 0,
  29                (delay_data_vec_capacity - old_capacity)
  30                * sizeof(*delay_data_vec));
  31 }
  32
  33 uint16_t
  34 alloc_delay_data(void)
  35 {
  36         const uint16_t rval = delay_data_vec_size;
  37
  38         if (rval < delay_data_vec_size)
  39                 error_func_msg_and_die("delay index overflow");
  40
  41         if (delay_data_vec_size == delay_data_vec_capacity)
  42                 expand_delay_data_vec();
  43
  44         ++delay_data_vec_size;
  45         return rval;
  46 }
  47
  48 void
  49 fill_delay_data(uint16_t delay_idx, struct timespec *val, bool isenter)
  50 {
  51         if (delay_idx >= delay_data_vec_size)
  52                 error_func_msg_and_die("delay_idx >= delay_data_vec_size");
  53
  54         struct timespec *ts;
  55         if (isenter)
  56                 ts = &(delay_data_vec[delay_idx].ts_enter);
  57         else
  58                 ts = &(delay_data_vec[delay_idx].ts_exit);
  59
  60         *ts = *val;
  61 }
  62
  63 static bool
  64 is_delay_timer_created(void)
  65 {
  66         return delay_timer != (timer_t) -1;
  67 }
  68
  69 bool
  70 is_delay_timer_armed(void)
  71 {
  72         return delay_timer_is_armed;
  73 }
  74
  75 void
  76 delay_timer_expired(void)
  77 {
  78         delay_timer_is_armed = false;
  79 }
  80
  81 void
  82 arm_delay_timer(const struct tcb *const tcp)
  83 {
  84         const struct itimerspec its = {
  85                 .it_value = tcp->delay_expiration_time
  86         };
  87
  88         if (timer_settime(delay_timer, TIMER_ABSTIME, &its, NULL))
  89                 perror_msg_and_die("timer_settime");
  90
  91         delay_timer_is_armed = true;
  92
  93         debug_func_msg("timer set to %lld.%09ld for pid %d",
  94                        (long long) tcp->delay_expiration_time.tv_sec,
  95                        (long) tcp->delay_expiration_time.tv_nsec,
  96                        tcp->pid);
  97 }
  98
  99 void
 100 delay_tcb(struct tcb *tcp, uint16_t delay_idx, bool isenter)
 101 {
 102         if (delay_idx >= delay_data_vec_size)
 103                 error_func_msg_and_die("delay_idx >= delay_data_vec_size");
 104
 105         debug_func_msg("delaying pid %d on %s",
 106                        tcp->pid, isenter ? "enter" : "exit");
 107         tcp->flags |= TCB_DELAYED;
 108
 109         struct timespec *ts_diff;
 110         if (isenter)
 111                 ts_diff = &(delay_data_vec[delay_idx].ts_enter);
 112         else
 113                 ts_diff = &(delay_data_vec[delay_idx].ts_exit);
 114
 115         struct timespec ts_now;
 116         clock_gettime(CLOCK_MONOTONIC, &ts_now);
 117         ts_add(&tcp->delay_expiration_time, &ts_now, ts_diff);
 118
 119         if (is_delay_timer_created()) {
 120                 struct itimerspec its;
 121                 if (timer_gettime(delay_timer, &its))
 122                         perror_msg_and_die("timer_gettime");
 123
 124                 const struct timespec *const ts_old = &its.it_value;
 125                 if (ts_nz(ts_old) && ts_cmp(ts_diff, ts_old) > 0)
 126                         return;
 127         } else {
 128                 if (timer_create(CLOCK_MONOTONIC, NULL, &delay_timer))
 129                         perror_msg_and_die("timer_create");
 130         }
 131
 132         arm_delay_timer(tcp);
 133 }