proc: selftests: test /proc/uptime
The only tests I could come up with for /proc/uptime are:
- test that values increase monotonically for 1 second,
- bounce around CPUs and test the same thing.
Avoid glibc like plague for affinity given patches like this:
https://marc.info/?l=linux-kernel&m=152130031912594&w=4
Link: http://lkml.kernel.org/r/20180317165235.GB3445@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/tools/testing/selftests/proc/proc-uptime.h b/tools/testing/selftests/proc/proc-uptime.h
new file mode 100644
index 0000000..d584419
--- /dev/null
+++ b/tools/testing/selftests/proc/proc-uptime.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright _ 2018 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#undef NDEBUG
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static unsigned long long xstrtoull(const char *p, char **end)
+{
+ if (*p == '0') {
+ *end = (char *)p + 1;
+ return 0;
+ } else if ('1' <= *p && *p <= '9') {
+ unsigned long long val;
+
+ errno = 0;
+ val = strtoull(p, end, 10);
+ assert(errno == 0);
+ return val;
+ } else
+ assert(0);
+}
+
+static void proc_uptime(int fd, uint64_t *uptime, uint64_t *idle)
+{
+ uint64_t val1, val2;
+ char buf[64], *p;
+ ssize_t rv;
+
+ /* save "p < end" checks */
+ memset(buf, 0, sizeof(buf));
+ rv = pread(fd, buf, sizeof(buf), 0);
+ assert(0 <= rv && rv <= sizeof(buf));
+ buf[sizeof(buf) - 1] = '\0';
+
+ p = buf;
+
+ val1 = xstrtoull(p, &p);
+ assert(p[0] == '.');
+ assert('0' <= p[1] && p[1] <= '9');
+ assert('0' <= p[2] && p[2] <= '9');
+ assert(p[3] == ' ');
+
+ val2 = (p[1] - '0') * 10 + p[2] - '0';
+ *uptime = val1 * 100 + val2;
+
+ p += 4;
+
+ val1 = xstrtoull(p, &p);
+ assert(p[0] == '.');
+ assert('0' <= p[1] && p[1] <= '9');
+ assert('0' <= p[2] && p[2] <= '9');
+ assert(p[3] == '\n');
+
+ val2 = (p[1] - '0') * 10 + p[2] - '0';
+ *idle = val1 * 100 + val2;
+
+ assert(p + 4 == buf + rv);
+}