[libc] Implement gettimeofday

[rtenneti]

Summary

Implement gettimeofday per
.../onlinepubs/9699919799/functions/gettimeofday.html.
This call clock_gettime to implement gettimeofday function.

Tested:
Limited unit test: This makes a call and checks that no error was
returned. Used nanosleep for 100 microseconds and verfified it
returns a value that elapses more than 100 microseconds and less
than 300 microseconds.

Co-authored-by: Jeff Bailey <[e-mail]>

[jeffbailey]

Did you intend to land this without review?

• smime.p7s3 KBDownload

[rtenneti]

It was a mistake, I was trying to upload an update to the patch by removing
tabs (I am guessing I must have have done git push and that might have
submitted the changes).

I would appreciate it if the following changes could be reviewed.

Thanks much
Raman

[michaelrj]

libc/spec/posix.td

48

these are already defined in spec.td as StructTimevalType and StructTimevalPtr

1083–1087

why did you move this?

libc/src/time/gettimeofday.cpp

14

we try to avoid calling entrypoints from other entrypoints. Here instead of calling clock_gettime it would be better to copy the code since it's just a simple syscall wrapper. If it was more complex then it would be better to extract it into a shared utility.

[sivachandra]

libc/spec/posix.td

1083–1087

They were likely rearranged to be in alphabetical order.

libc/test/src/time/gettimeofday_test.cpp

33

The less than check is always going to be flaky. Instead, verify that the next value is greater than or equal to 200 microseconds from the old value. Repeat with a 1000 microsecond delay to reinforce.

[rtenneti]

Made the changes in https://reviews.llvm.org/D138064

Thanks for the comments.

libc/config/linux/aarch64/entrypoints.txt

list(APPEND TARGET_LIBC_ENTRYPOINTS
     libc.src.threads.tss_set
 
     # time.h entrypoints
     libc.src.time.asctime
     libc.src.time.asctime_r
     libc.src.time.clock_gettime
     libc.src.time.clock
     libc.src.time.difftime
+    libc.src.time.gettimeofday
     libc.src.time.gmtime
     libc.src.time.gmtime_r
     libc.src.time.mktime
     libc.src.time.nanosleep
     libc.src.time.time
 
     # unistd.h entrypoints
     libc.src.unistd.environ

libc/config/linux/api.td

let Types = [
     "size_t",
     "__bsearchcompare_t",
     "__qsortcompare_t",
     "__atexithandler_t",
   ];
 }
 
 def TimeAPI : PublicAPI<"time.h"> {
-  let Types = ["clock_t", "time_t", "struct tm", "struct timespec", "clockid_t",];
+  let Types = [
+    "clock_t",
+    "time_t",
+    "struct tm",
+    "struct timespec",
+    "struct timeval",
+    "clockid_t",
+  ];
 }
 
 def ErrnoAPI : PublicAPI<"errno.h"> {
   let Macros = [
     ErrnoMacro,
     // We largely depend on linux/errno.h to give us the
     // various error macro definitions. However, some libc
     // implementations have chosen to provide definitions

 }
 
 def SysResourceAPI : PublicAPI<"sys/resource.h"> {
   let Types = ["rlim_t", "struct rlimit"];
 }
 
 def SysStatAPI : PublicAPI<"sys/stat.h"> {
   let Types = ["mode_t", "dev_t", "ino_t", "nlink_t", "uid_t", "gid_t", "off_t",
-               "struct timespec", "blksize_t", "blkcnt_t", "struct stat"];
+               "struct timespec", "struct timeval", "blksize_t", "blkcnt_t",
+         "struct stat"];
 }
 
 def SysWaitAPI : PublicAPI<"sys/wait.h"> {
   let Types = ["pid_t", "struct rusage"];
 }
 
 def SysSendfileAPI : PublicAPI<"sys/sendfile.h"> {
   let Types = ["off_t", "size_t", "ssize_t"];

libc/config/linux/x86_64/entrypoints.txt

list(APPEND TARGET_LIBC_ENTRYPOINTS
     libc.src.threads.tss_set
 
     # time.h entrypoints
     libc.src.time.asctime
     libc.src.time.asctime_r
     libc.src.time.clock_gettime
     libc.src.time.clock
     libc.src.time.difftime
+    libc.src.time.gettimeofday
     libc.src.time.gmtime
     libc.src.time.gmtime_r
     libc.src.time.mktime
     libc.src.time.nanosleep
     libc.src.time.time
 
     # unistd.h entrypoints
     libc.src.unistd.environ

libc/docs/date_and_time.rst

 clock_getres
 clock_gettime         |check|
 clock_nanosleep
 clock_settime
 ctime
 ctime_r
 difftime              |check|
 getdate
+gettimeofday          |check|
 gmtime                |check|
 gmtime_r              |check|
 localtime
 localtime_r
 mktime                |check|
 nanosleep             |check|
 strftime
 strptime

libc/include/CMakeLists.txt

add_gen_header(
   DEPENDS
     .llvm_libc_common_h
     .llvm-libc-macros.time_macros
     .llvm-libc-types.time_t
     .llvm-libc-types.clock_t
     .llvm-libc-types.clockid_t
     .llvm-libc-types.struct_tm
     .llvm-libc-types.struct_timespec
+    .llvm-libc-types.struct_timeval
 )
 
 add_gen_header(
   threads
   DEF_FILE threads.h.def
   GEN_HDR threads.h
   DEPENDS
     .llvm_libc_common_h

libc/spec/posix.td

 def StructDirent : NamedType<"struct dirent">;
 def StructDirentPtr : PtrType<StructDirent>;
 def StructDirentPtrPtr : PtrType<StructDirentPtr>;
 def ConstStructDirentPtrPtr : ConstType<StructDirentPtrPtr>;
 
 def StructTimeSpec : NamedType<"struct timespec">;
 def StructTimeSpecPtr : PtrType<StructTimeSpec>;
 
+def StructTimeVal : NamedType<"struct timeval">;
+def StructTimeValPtr : PtrType<StructTimeVal>;
+
 def ExecArgvT : NamedType<"__exec_argv_t">;
 def ExecEnvpT : NamedType<"__exec_envp_t">;
 
 def AtForkCallbackT : NamedType<"__atfork_callback_t">;
 
 def PosixSpawnFileActionsT : NamedType<"posix_spawn_file_actions_t">;
 def PosixSpawnFileActionsTPtr : PtrType<PosixSpawnFileActionsT>;
 def ConstPosixSpawnFileActionsTPtr : ConstType<PosixSpawnFileActionsTPtr>;
[
           [ArgSpec<ConstStructRLimitPtr>]
         >,
     ]
   >;
 
   HeaderSpec SysStat = HeaderSpec<
     "sys/stat.h",
     [], // Macros
-    [ModeTType, DevT, InoT, UidT, GidT, StructTimeSpec, BlkSizeT, BlkCntT, OffTType, NLinkT, StatType], // Types
+    [
+        ModeTType,
+  DevT,
+  InoT,
+  UidT,
+  GidT,
+  StructTimeSpec,
+  StructTimeVal,
+  BlkSizeT,
+  BlkCntT,
+  OffTType,
+  NLinkT,
+  StatType,
+    ], // Types
     [], // Enumerations
     [
         FunctionSpec<
           "chmod",
           RetValSpec<IntType>,
           [ArgSpec<ConstCharPtr>, ArgSpec<ModeTType>]
         >,
         FunctionSpec<
HeaderSpec Dirent = HeaderSpec<
               [ArgSpec<DIRPtr>]
           >,
       ]
   >;
 
   HeaderSpec Time = HeaderSpec<
       "time.h",
       [], // Macros
-      [ClockIdT, StructTimeSpec], // Types
+      [ClockIdT, StructTimeSpec, StructTimeVal], // Types
       [], // Enumerations
       [
           FunctionSpec<
+              "clock_gettime",
+              RetValSpec<IntType>,
+              [ArgSpec<ClockIdT>, ArgSpec<StructTimeSpecPtr>]
+          >,
+          FunctionSpec<
+              "gettimeofday",
+              RetValSpec<IntType>,
+              [ArgSpec<StructTimeValPtr>, ArgSpec<VoidPtr>]
+          >,
+          FunctionSpec<
               "nanosleep",
               RetValSpec<IntType>,
               [
-                ArgSpec<StructTimeSpecPtr>,
-                ArgSpec<StructTimeSpecPtr>,
-              ]
+             ArgSpec<StructTimeSpecPtr>,
+             ArgSpec<StructTimeSpecPtr>,
+        ]
           >,
-          FunctionSpec<
-              "clock_gettime",
-              RetValSpec<IntType>,
-              [ArgSpec<ClockIdT>,ArgSpec<StructTimeSpecPtr>]
-          >,
       ]
   >;
 
   HeaderSpec SysWait = HeaderSpec<
     "sys/wait.h",
     [], // Macros
     [PidT, StructRUsage],
     [], // Enumerations

libc/src/time/CMakeLists.txt

SRCS
     difftime.cpp
   HDRS
     difftime.h
   DEPENDS
     libc.include.time
 )
 
 add_entrypoint_object(
+  gettimeofday
+  SRCS
+    gettimeofday.cpp
+  HDRS
+    gettimeofday.h
+  DEPENDS
+    .clock_gettime
+    libc.include.errno
+    libc.include.time
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
+
+add_entrypoint_object(
   gmtime
   SRCS
     gmtime.cpp
   HDRS
     gmtime.h
   DEPENDS
     .time_utils
     libc.include.time

libc/src/time/gettimeofday.h

+//===-- Implementation header of gettimeofday -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_TIME_GETTIMEOFDAY_H
+#define LLVM_LIBC_SRC_TIME_GETTIMEOFDAY_H
+
+#include <time.h>
+
+namespace __llvm_libc {
+
+int gettimeofday(struct timeval *tv, void *tz);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_TIME_GETTIMEOFDAY_H
+
+#include "include/time.h"

libc/src/time/gettimeofday.cpp

+//===-- Implementation of gettimeofday function ---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/time/gettimeofday.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/time/clock_gettime.h"
+
+#include <errno.h>
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, gettimeofday,
+                   (struct timeval * tv, [[maybe_unused]] void *unused)) {
+  if (tv == nullptr)
+    return 0;
+  clockid_t clockid = CLOCK_REALTIME;
+  struct timespec tp;
+  long ret_val = __llvm_libc::clock_gettime(clockid, &tp);
+  if (ret_val < 0)
+    return -1;
+  tv->tv_sec = tp.tv_sec;
+  tv->tv_usec = tp.tv_nsec / 1000;
+  return 0;
+}
+
+} // namespace __llvm_libc

libc/test/src/time/CMakeLists.txt

SUITE
     libc_time_unittests
   SRCS
     difftime_test.cpp
   DEPENDS
     libc.src.time.difftime
 )
 
 add_libc_unittest(
+  gettimeofday
+  SUITE
+    libc_time_unittests
+  SRCS
+    gettimeofday_test.cpp
+  HDRS
+    TmHelper.h
+    TmMatcher.h
+  CXX_STANDARD
+    20
+  DEPENDS
+    libc.include.errno
+    libc.include.time
+    libc.src.time.gettimeofday
+    libc.src.time.nanosleep
+)
+
+add_libc_unittest(
   gmtime
   SUITE
     libc_time_unittests
   SRCS
     gmtime_test.cpp
   HDRS
     TmMatcher.h
   DEPENDS

libc/test/src/time/gettimeofday_test.cpp

+//===-- Unittests for gettimeofday ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <errno.h>
+#include <time.h>
+
+#include "src/time/gettimeofday.h"
+#include "src/time/nanosleep.h"
+#include "test/ErrnoSetterMatcher.h"
+#include "utils/UnitTest/Test.h"
+
+namespace cpp = __llvm_libc::cpp;
+
+TEST(LlvmLibcGettimeofday, SmokeTest) {
+  using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
+  void *tz = nullptr;
+  struct timeval tv;
+  int ret = __llvm_libc::gettimeofday(&tv, tz);
+  ASSERT_EQ(ret, 0);
+
+  // Sleep for 200 microsceconds.
+  struct timespec tim = {0, 200 * 1000};
+  struct timespec tim2 = {0, 0};
+  ret = __llvm_libc::nanosleep(&tim, &tim2);
+
+  // Call gettimeofday again and verify that it is more 100 microscecods and
+  // less than 300 microseconds,
+  struct timeval tv1;
+  ret = __llvm_libc::gettimeofday(&tv1, tz);
+  ASSERT_EQ(ret, 0);
+  ASSERT_GT(tv1.tv_usec - tv.tv_usec, 100);
+  ASSERT_LT(tv1.tv_usec - tv.tv_usec, 300);
+}