libc: Implement times function

https://pubs.opengroup.org/onlinepubs/009604599/functions/times.html

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: If2cccfedd532a77f86035d16d36d94ae38d8f09c

include/sys/times.h

@@ -0,0 +1,81 @@
+/****************************************************************************
+ * include/sys/times.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_SYS_TIMES_H
+#define __INCLUDE_SYS_TIMES_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <sys/types.h>
+
+/****************************************************************************
+ * Public Type Definitions
+ ****************************************************************************/
+
+/* Structure describing CPU time used by a process and its children.  */
+
+struct tms
+{
+  clock_t tms_utime;  /* User CPU time.  */
+  clock_t tms_stime;  /* System CPU time.  */
+  clock_t tms_cutime; /* User CPU time of dead children.  */
+  clock_t tms_cstime; /* System CPU time of dead children.  */
+};
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: times
+ *
+ * Description:
+ *   The times() function shall fill the tms structure pointed to by buffer
+ *   with time-accounting information.
+ *
+ * Returned Value:
+ *   Upon successful completion, times() shall return the elapsed real time,
+ *   in clock ticks, since an arbitrary point in the past (for example,
+ *   system start-up time). This point does not change from one invocation
+ *   of times() within the process to another. The return value may overflow
+ *   the possible range of type clock_t. If times() fails, (clock_t)-1 shall
+ *   be returned and errno set to indicate the error.
+ *
+ ****************************************************************************/
+
+clock_t times(FAR struct tms *buffer);
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __INCLUDE_SYS_TIMES_H */

libs/libc/unistd/Make.defs

@@ -23,7 +23,7 @@
 CSRCS += lib_access.c lib_daemon.c lib_swab.c lib_pathconf.c lib_sysconf.c
 CSRCS += lib_getopt_common.c lib_getopt.c lib_getopt_long.c
 CSRCS += lib_getopt_longonly.c lib_getoptvars.c lib_getoptargp.c
-CSRCS += lib_getopterrp.c lib_getoptindp.c lib_getoptoptp.c
+CSRCS += lib_getopterrp.c lib_getoptindp.c lib_getoptoptp.c lib_times.c
 CSRCS += lib_alarm.c lib_fstatvfs.c lib_statvfs.c lib_sleep.c lib_nice.c
 CSRCS += lib_usleep.c lib_seteuid.c lib_setegid.c lib_geteuid.c lib_getegid.c
 CSRCS += lib_setreuid.c lib_setregid.c lib_getrusage.c lib_utime.c lib_utimes.c

libs/libc/unistd/lib_times.c

@@ -0,0 +1,61 @@
+/****************************************************************************
+ * libs/libc/unistd/lib_times.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <errno.h>
+#include <string.h>
+#include <sys/times.h>
+#include <time.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: times
+ *
+ * Description:
+ *   The times() function shall fill the tms structure pointed to by buffer
+ *   with time-accounting information.
+ *
+ * Returned Value:
+ *   Upon successful completion, times() shall return the elapsed real time,
+ *   in clock ticks, since an arbitrary point in the past (for example,
+ *   system start-up time). This point does not change from one invocation
+ *   of times() within the process to another. The return value may overflow
+ *   the possible range of type clock_t. If times() fails, (clock_t)-1 shall
+ *   be returned and errno set to indicate the error.
+ *
+ ****************************************************************************/
+
+clock_t times(FAR struct tms *buffer)
+{
+  if (buffer == NULL)
+    {
+      set_errno(EINVAL);
+      return -1;
+    }
+
+  memset(buffer, 0, sizeof(*buffer));
+  return clock();
+}