selftests/proc/proc-uptime-001.c

0001 /*
0002  * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
0003  *
0004  * Permission to use, copy, modify, and distribute this software for any
0005  * purpose with or without fee is hereby granted, provided that the above
0006  * copyright notice and this permission notice appear in all copies.
0007  *
0008  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
0009  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
0010  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
0011  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
0012  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
0013  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
0014  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
0015  */
0016 // Test that values in /proc/uptime increment monotonically.
0017 #undef NDEBUG
0018 #include <assert.h>
0019 #include <stdint.h>
0020 #include <sys/types.h>
0021 #include <sys/stat.h>
0022 #include <fcntl.h>
0023
0024 #include "proc-uptime.h"
0025
0026 int main(void)
0027 {
0028     uint64_t start, u0, u1, i0, i1;
0029     int fd;
0030
0031     fd = open("/proc/uptime", O_RDONLY);
0032     assert(fd >= 0);
0033
0034     proc_uptime(fd, &u0, &i0);
0035     start = u0;
0036     do {
0037         proc_uptime(fd, &u1, &i1);
0038         assert(u1 >= u0);
0039         assert(i1 >= i0);
0040         u0 = u1;
0041         i0 = i1;
0042     } while (u1 - start < 100);
0043
0044     return 0;
0045 }