support _POSIX_CPUTIME

Bug: 18490039
Change-Id: I01fa83b48e1b908de1f227b6e4f98e280bcd50ee
diff --git a/libc/Android.mk b/libc/Android.mk
index ef1fb9b..13fc297 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -98,6 +98,7 @@
     bionic/chown.cpp \
     bionic/clearenv.cpp \
     bionic/clock.cpp \
+    bionic/clock_getcpuclockid.cpp \
     bionic/clock_nanosleep.cpp \
     bionic/clone.cpp \
     bionic/__cmsg_nxthdr.cpp \
diff --git a/libc/bionic/clock_getcpuclockid.cpp b/libc/bionic/clock_getcpuclockid.cpp
new file mode 100644
index 0000000..5511eb4
--- /dev/null
+++ b/libc/bionic/clock_getcpuclockid.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <time.h>
+
+#include "private/ErrnoRestorer.h"
+
+int clock_getcpuclockid(pid_t pid, clockid_t* clockid) {
+  ErrnoRestorer errno_restorer;
+
+  // The tid is stored in the top bits, but negated.
+  clockid_t result = ~static_cast<clockid_t>(pid) << 3;
+  // Bits 0 and 1: clock type (0 = CPUCLOCK_PROF, 1 = CPUCLOCK_VIRT, 2 = CPUCLOCK_SCHED).
+  result |= 2;
+  // Bit 2: thread (set) or process (clear). Bit 2 already 0.
+
+  timespec ts;
+  if (clock_getres(result, &ts) == -1) {
+    return ESRCH;
+  }
+
+  *clockid = result;
+  return 0;
+}
diff --git a/libc/include/machine/posix_limits.h b/libc/include/machine/posix_limits.h
index e5a299b..939a1de 100644
--- a/libc/include/machine/posix_limits.h
+++ b/libc/include/machine/posix_limits.h
@@ -41,7 +41,7 @@
 #define _POSIX_CHILD_MAX            25
 #define _POSIX_CHOWN_RESTRICTED     1  /* yes, chown requires appropriate privileges */
 #define _POSIX_CLOCK_SELECTION      200809L
-#define _POSIX_CPUTIME              -1  /* clock_getcpuclockid() not implemented */
+#define _POSIX_CPUTIME              200809L
 #define _POSIX_DELAYTIMER_MAX       32
 #define _POSIX_FSYNC                200809L  /* fdatasync() supported */
 #define _POSIX_HOST_NAME_MAX        255
diff --git a/libc/include/time.h b/libc/include/time.h
index e34eb34..1b0f6a1 100644
--- a/libc/include/time.h
+++ b/libc/include/time.h
@@ -85,6 +85,8 @@
 
 extern clock_t clock(void) __LIBC_ABI_PUBLIC__;
 
+extern int clock_getcpuclockid(pid_t, clockid_t*) __LIBC_ABI_PUBLIC__;
+
 extern int clock_getres(clockid_t, struct timespec*) __LIBC_ABI_PUBLIC__;
 extern int clock_gettime(clockid_t, struct timespec*) __LIBC_ABI_PUBLIC__;
 extern int clock_nanosleep(clockid_t, int, const struct timespec*, struct timespec*) __LIBC_ABI_PUBLIC__;