From a6c02e29c1e1f2bb810839dc40e3f289cb2de393 Mon Sep 17 00:00:00 2001
From: vcbchang <vcbchang@qq.com>
Date: Mon, 2 Aug 2021 11:14:13 +0800
Subject: [PATCH] =?UTF-8?q?fix:=E4=BF=AE=E5=A4=8D=E5=9C=A8=E4=BD=BF?=
 =?UTF-8?q?=E7=94=A8GetCputime=E6=97=B6=E7=94=B1clockid=E8=AE=A1=E7=AE=97p?=
 =?UTF-8?q?id=E6=88=96tid=E6=97=B6=E5=87=BA=E7=8E=B0=E7=9A=84=E9=94=99?=
 =?UTF-8?q?=E8=AF=AF?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

【背景】原来代码在计算由clockid计算pid或tid时用的是移位的方式，由于对于有符号和无符号数结果可能不一致，故这里对计算方法做了修改，修改为计算clockid的逆运算。

【修改方案】
计算pid或tid为计算clockid的逆运算

re #I4249G
Signed-off-by: vcbchang <vcbchang@qq.com>
Change-Id: I2952232ec7d8fc2d0c47163b00d0c772648a2bf8
---
 compat/posix/src/time.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/compat/posix/src/time.c b/compat/posix/src/time.c
index 865f8dbd..42ee50ae 100644
--- a/compat/posix/src/time.c
+++ b/compat/posix/src/time.c
@@ -452,11 +452,25 @@ int clock_settime(clockid_t clockID, const struct timespec *tp)
 }
 
 #ifdef LOSCFG_KERNEL_CPUP
+inline UINT32 GetTidFromClockID(clockid_t clockID)
+{
+    // In musl/src/thread/pthread_getcpuclockid.c, we know 'clockid = (-tid - 1) * 8 + 6' 
+    UINT32 tid = -(clockID - 6) / 8 - 1; // 6 8 1 inverse operation from clockID to tid
+    return tid;
+}
+
+inline const pid_t GetPidFromClockID(clockid_t clockID)
+{
+    // In musl/src/time/clock_getcpuclockid.c, we know 'clockid = (-pid - 1) * 8 + 2'
+    const pid_t pid = -(clockID - 2) / 8 - 1; // 2 8 1 inverse operation from clockID to pid
+    return pid;
+}
+
 static int PthreadGetCputime(clockid_t clockID, struct timespec *ats)
 {
     uint64_t runtime;
     UINT32 intSave;
-    UINT32 tid = ((UINT32) ~((UINT32)(clockID) >> CPUCLOCK_ID_OFFSET));
+    UINT32 tid = GetTidFromClockID(clockID);
 
     if (OS_TID_CHECK_INVALID(tid)) {
         return -EINVAL;
@@ -482,7 +496,7 @@ static int ProcessGetCputime(clockid_t clockID, struct timespec *ats)
 {
     UINT64 runtime;
     UINT32 intSave;
-    const pid_t pid = ((pid_t) ~((UINT32)(clockID) >> CPUCLOCK_ID_OFFSET));
+    const pid_t pid = GetPidFromClockID(clockID);
     LosProcessCB *spcb = NULL;
 
     if (OsProcessIDUserCheckInvalid(pid) || pid < 0) {
@@ -524,7 +538,7 @@ static int GetCputime(clockid_t clockID, struct timespec *tp)
 static int CheckClock(const clockid_t clockID)
 {
     int error = 0;
-    const pid_t pid = ((pid_t) ~((UINT32)(clockID) >> CPUCLOCK_ID_OFFSET));
+    const pid_t pid = GetPidFromClockID(clockID);
 
     if (!((UINT32)clockID & CPUCLOCK_PERTHREAD_MASK)) {
         LosProcessCB *spcb = NULL;
-- 
GitLab