1 /* 2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com> 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 #undef NDEBUG 17 #include <assert.h> 18 #include <errno.h> 19 #include <string.h> 20 #include <stdlib.h> 21 #include <unistd.h> 22 #include <time.h> 23 24 #include "proc.h" 25 26 static uint64_t clock_boottime(void) 27 { 28 struct timespec ts; 29 int err; 30 31 err = clock_gettime(CLOCK_BOOTTIME, &ts); 32 assert(err >= 0); 33 34 return (ts.tv_sec * 100) + (ts.tv_nsec / 10000000); 35 } 36 37 static uint64_t proc_uptime(int fd) 38 { 39 uint64_t val1, val2; 40 char buf[64], *p; 41 ssize_t rv; 42 43 /* save "p < end" checks */ 44 memset(buf, 0, sizeof(buf)); 45 rv = pread(fd, buf, sizeof(buf), 0); 46 assert(0 <= rv && rv <= sizeof(buf)); 47 buf[sizeof(buf) - 1] = '\0'; 48 49 p = buf; 50 51 val1 = xstrtoull(p, &p); 52 assert(p[0] == '.'); 53 assert('0' <= p[1] && p[1] <= '9'); 54 assert('0' <= p[2] && p[2] <= '9'); 55 assert(p[3] == ' '); 56 57 val2 = (p[1] - '0') * 10 + p[2] - '0'; 58 59 return val1 * 100 + val2; 60 } 61