tools/nolibc: add timer functions

This is used in various selftests and will be handy when integrating
those with nolibc.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20250428-nolibc-misc-v2-9-3c043eeab06c@linutronix.de
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

tools/include/nolibc/time.h

@@ -15,6 +15,7 @@
 #include "types.h"
 #include "sys.h"
 
+#include <linux/signal.h>
 #include <linux/time.h>
 
 static __inline__
@@ -120,4 +121,89 @@ time_t time(time_t *tptr)
 	return tv.tv_sec;
 }
 
+
+/*
+ * int timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid);
+ * int timer_gettime(timer_t timerid, struct itimerspec *curr_value);
+ * int timer_settime(timer_t timerid, int flags, const struct itimerspec *new_value, struct itimerspec *old_value);
+ */
+
+static __attribute__((unused))
+int sys_timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid)
+{
+	return my_syscall3(__NR_timer_create, clockid, evp, timerid);
+}
+
+static __attribute__((unused))
+int timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid)
+{
+	return __sysret(sys_timer_create(clockid, evp, timerid));
+}
+
+static __attribute__((unused))
+int sys_timer_delete(timer_t timerid)
+{
+	return my_syscall1(__NR_timer_delete, timerid);
+}
+
+static __attribute__((unused))
+int timer_delete(timer_t timerid)
+{
+	return __sysret(sys_timer_delete(timerid));
+}
+
+static __attribute__((unused))
+int sys_timer_gettime(timer_t timerid, struct itimerspec *curr_value)
+{
+#if defined(__NR_timer_gettime)
+	return my_syscall2(__NR_timer_gettime, timerid, curr_value);
+#elif defined(__NR_timer_gettime64)
+	struct __kernel_itimerspec kcurr_value;
+	int ret;
+
+	ret = my_syscall2(__NR_timer_gettime64, timerid, &kcurr_value);
+	__nolibc_timespec_kernel_to_user(&kcurr_value.it_interval, &curr_value->it_interval);
+	__nolibc_timespec_kernel_to_user(&kcurr_value.it_value, &curr_value->it_value);
+	return ret;
+#else
+	return __nolibc_enosys(__func__, timerid, curr_value);
+#endif
+}
+
+static __attribute__((unused))
+int timer_gettime(timer_t timerid, struct itimerspec *curr_value)
+{
+	return __sysret(sys_timer_gettime(timerid, curr_value));
+}
+
+static __attribute__((unused))
+int sys_timer_settime(timer_t timerid, int flags,
+		      const struct itimerspec *new_value, struct itimerspec *old_value)
+{
+#if defined(__NR_timer_settime)
+	return my_syscall4(__NR_timer_settime, timerid, flags, new_value, old_value);
+#elif defined(__NR_timer_settime64)
+	struct __kernel_itimerspec knew_value, kold_value;
+	int ret;
+
+	__nolibc_timespec_user_to_kernel(&new_value->it_value, &knew_value.it_value);
+	__nolibc_timespec_user_to_kernel(&new_value->it_interval, &knew_value.it_interval);
+	ret = my_syscall4(__NR_timer_settime64, timerid, flags, &knew_value, &kold_value);
+	if (old_value) {
+		__nolibc_timespec_kernel_to_user(&kold_value.it_interval, &old_value->it_interval);
+		__nolibc_timespec_kernel_to_user(&kold_value.it_value, &old_value->it_value);
+	}
+	return ret;
+#else
+	return __nolibc_enosys(__func__, timerid, flags, new_value, old_value);
+#endif
+}
+
+static __attribute__((unused))
+int timer_settime(timer_t timerid, int flags,
+		  const struct itimerspec *new_value, struct itimerspec *old_value)
+{
+	return __sysret(sys_timer_settime(timerid, flags, new_value, old_value));
+}
+
 #endif /* _NOLIBC_TIME_H */

tools/include/nolibc/types.h

@@ -188,6 +188,7 @@ struct stat {
 };
 
 typedef __kernel_clockid_t clockid_t;
+typedef int timer_t;
 
 /* WARNING, it only deals with the 4096 first majors and 256 first minors */
 #define makedev(major, minor) ((dev_t)((((major) & 0xfff) << 8) | ((minor) & 0xff)))

tools/testing/selftests/nolibc/nolibc-test.c

@@ -905,6 +905,56 @@ int test_stat_timestamps(void)
 	return 0;
 }
 
+int test_timer(void)
+{
+	struct itimerspec timerspec;
+	struct sigevent evp;
+	timer_t timer;
+	int ret;
+
+	evp.sigev_notify = SIGEV_NONE;
+
+	ret = timer_create(CLOCK_MONOTONIC, &evp, &timer);
+	if (ret)
+		return ret;
+
+	timerspec = (struct itimerspec) {
+		.it_value.tv_sec = 1000000,
+	};
+	ret = timer_settime(timer, 0, &timerspec, NULL);
+	if (ret)
+		goto err;
+
+	timerspec = (struct itimerspec) {
+		.it_value.tv_sec = -1,
+		.it_value.tv_nsec = -1,
+		.it_interval.tv_sec = -1,
+		.it_interval.tv_nsec = -1,
+	};
+	ret = timer_gettime(timer, &timerspec);
+	if (ret)
+		goto err;
+
+	errno = EINVAL;
+	ret = -1;
+
+	if (timerspec.it_interval.tv_sec || timerspec.it_interval.tv_nsec)
+		goto err;
+
+	if (timerspec.it_value.tv_sec > 1000000)
+		goto err;
+
+	ret = timer_delete(timer);
+	if (ret)
+		return ret;
+
+	return 0;
+
+err:
+	timer_delete(timer);
+	return ret;
+}
+
 int test_uname(void)
 {
 	struct utsname buf;
@@ -1186,6 +1236,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(stat_fault);        EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break;
 		CASE_TEST(stat_timestamps);   EXPECT_SYSZR(1, test_stat_timestamps()); break;
 		CASE_TEST(symlink_root);      EXPECT_SYSER(1, symlink("/", "/"), -1, EEXIST); break;
+		CASE_TEST(timer);             EXPECT_SYSZR(1, test_timer()); break;
 		CASE_TEST(uname);             EXPECT_SYSZR(proc, test_uname()); break;
 		CASE_TEST(uname_fault);       EXPECT_SYSER(1, uname(NULL), -1, EFAULT); break;
 		CASE_TEST(unlink_root);       EXPECT_SYSER(1, unlink("/"), -1, EISDIR); break;