53 lines
861 B
C
53 lines
861 B
C
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/*
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* gcc time_past.c -o time_past.so -shared -ldl
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* LD_PRELOAD=./time_past.so PAST_DAYS=2 ./test
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*/
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#define _GNU_SOURCE
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#include <dlfcn.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <stdarg.h>
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#include <fcntl.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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typedef time_t (*time_type) (time_t *t);
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static time_type next_time;
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static int time_past = 0;
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static char *past = NULL;
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time_t time (time_t *t)
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{
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time_t res;
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if (NULL == next_time)
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{
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next_time = dlsym (RTLD_NEXT, "time");
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assert (NULL != next_time);
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}
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if (NULL == past) {
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const char *past = getenv ("PAST_DAYS");
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if (NULL == past) {
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fputs ("No PAST_DAYS defined\n", stderr);
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}
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time_past = atoi (past);
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}
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res = next_time (t);
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res -= 24*60*60*time_past;
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if (NULL != t) {
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*t = res;
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}
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return res;
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}
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