20 files changed, 260 insertions, 15 deletions
diff --git a/libc/src/__support/time/CMakeLists.txt b/libc/src/__support/time/CMakeLists.txt
index 8247e79..3851037 100644
--- a/libc/src/__support/time/CMakeLists.txt
+++ b/libc/src/__support/time/CMakeLists.txt
@@ -19,3 +19,12 @@ add_object_library(
   DEPENDS
     libc.src.__support.time.${LIBC_TARGET_OS}.clock_gettime
 )
+
+if(TARGET libc.src.__support.time.${LIBC_TARGET_OS}.clock_settime)  
+  add_object_library(
+    clock_settime
+    ALIAS
+    DEPENDS
+      libc.src.__support.time.${LIBC_TARGET_OS}.clock_settime
+  )
+endif()
diff --git a/libc/src/__support/time/clock_settime.h b/libc/src/__support/time/clock_settime.h
new file mode 100644
index 0000000..d8d305c
--- /dev/null
+++ b/libc/src/__support/time/clock_settime.h
@@ -0,0 +1,22 @@
+//===--- clock_settime linux implementation ---------------------*- 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___SUPPORT_TIME_CLOCK_SETTIME_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_CLOCK_SETTIME_H
+
+#include "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/error_or.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
+ErrorOr<int> clock_settime(clockid_t clockid, const timespec *ts);
+} // namespace internal
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_CLOCK_SETTIME_H
diff --git a/libc/src/__support/time/linux/CMakeLists.txt b/libc/src/__support/time/linux/CMakeLists.txt
index 6fec7ee..4785295 100644
--- a/libc/src/__support/time/linux/CMakeLists.txt
+++ b/libc/src/__support/time/linux/CMakeLists.txt
@@ -14,6 +14,21 @@ add_object_library(
     libc.src.__support.OSUtil.linux.vdso
 )
 
+add_object_library(
+  clock_settime
+  HDRS
+    ../clock_settime.h
+  SRCS
+    clock_settime.cpp
+  DEPENDS
+    libc.include.sys_syscall
+    libc.hdr.types.struct_timespec
+    libc.hdr.types.clockid_t
+    libc.src.__support.common
+    libc.src.__support.error_or
+    libc.src.__support.OSUtil.osutil
+)
+
 add_header_library(
   clock_conversion
   HDRS
diff --git a/libc/src/__support/time/linux/clock_settime.cpp b/libc/src/__support/time/linux/clock_settime.cpp
new file mode 100644
index 0000000..dd42610
--- /dev/null
+++ b/libc/src/__support/time/linux/clock_settime.cpp
@@ -0,0 +1,53 @@
+//===--- clock_settime linux implementation ---------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/__support/time/clock_settime.h"
+#include "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/OSUtil/syscall.h"
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+#include <sys/syscall.h>
+
+#if defined(SYS_clock_settime64)
+#include <linux/time_types.h>
+#endif
+
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
+ErrorOr<int> clock_settime(clockid_t clockid, const timespec *ts) {
+  int ret;
+#if defined(SYS_clock_settime)
+  ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_settime,
+                                          static_cast<long>(clockid),
+                                          reinterpret_cast<long>(ts));
+#elif defined(SYS_clock_settime64)
+  static_assert(
+      sizeof(time_t) == sizeof(int64_t),
+      "SYS_clock_settime64 requires struct timespec with 64-bit members.");
+
+  __kernel_timespec ts64{};
+
+  // Populate the 64-bit kernel structure from the user-provided timespec
+  ts64.tv_sec = static_cast<decltype(ts64.tv_sec)>(ts->tv_sec);
+  ts64.tv_nsec = static_cast<decltype(ts64.tv_nsec)>(ts->tv_nsec);
+
+  ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_settime64,
+                                          static_cast<long>(clockid),
+                                          reinterpret_cast<long>(&ts64));
+#else
+#error "SYS_clock_settime and SYS_clock_settime64 syscalls not available."
+#endif
+  if (ret < 0)
+    return Error(-ret);
+  return ret;
+}
+
+} // namespace internal
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/time/CMakeLists.txt b/libc/src/time/CMakeLists.txt
index ec942e3..4d647c2 100644
--- a/libc/src/time/CMakeLists.txt
+++ b/libc/src/time/CMakeLists.txt
@@ -245,3 +245,11 @@ add_entrypoint_object(
   DEPENDS
     .${LIBC_TARGET_OS}.clock_getres
 )
+
+add_entrypoint_object(
+  clock_settime
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.clock_settime
+)
+
diff --git a/libc/src/time/clock_settime.h b/libc/src/time/clock_settime.h
new file mode 100644
index 0000000..9321dd1
--- /dev/null
+++ b/libc/src/time/clock_settime.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for clock_settime function --------*- 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_CLOCK_SETTIME_H
+#define LLVM_LIBC_SRC_TIME_CLOCK_SETTIME_H
+
+#include "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int clock_settime(clockid_t clockid, const timespec *tp);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_TIME_CLOCK_SETTIME_H
diff --git a/libc/src/time/linux/CMakeLists.txt b/libc/src/time/linux/CMakeLists.txt
index a6ec7c7..6ea0459 100644
--- a/libc/src/time/linux/CMakeLists.txt
+++ b/libc/src/time/linux/CMakeLists.txt
@@ -55,6 +55,19 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  clock_settime
+  SRCS
+    clock_settime.cpp
+  HDRS
+    ../clock_settime.h
+  DEPENDS
+    libc.hdr.types.clockid_t
+    libc.hdr.types.struct_timespec
+    libc.src.__support.time.clock_settime
+    libc.src.errno.errno
+)
+
+add_entrypoint_object(
   gettimeofday
   SRCS
     gettimeofday.cpp
diff --git a/libc/src/time/linux/clock.cpp b/libc/src/time/linux/clock.cpp
index c38697c..c560bd1 100644
--- a/libc/src/time/linux/clock.cpp
+++ b/libc/src/time/linux/clock.cpp
@@ -19,7 +19,7 @@ namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(clock_t, clock, ()) {
   using namespace time_units;
-  struct timespec ts;
+  timespec ts;
   auto result = internal::clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
   if (!result.has_value()) {
     libc_errno = result.error();
diff --git a/libc/src/time/linux/clock_gettime.cpp b/libc/src/time/linux/clock_gettime.cpp
index b3fcd2b..52ace2a 100644
--- a/libc/src/time/linux/clock_gettime.cpp
+++ b/libc/src/time/linux/clock_gettime.cpp
@@ -15,8 +15,7 @@
 namespace LIBC_NAMESPACE_DECL {
 
 // TODO(michaelrj): Move this into time/linux with the other syscalls.
-LLVM_LIBC_FUNCTION(int, clock_gettime,
-                   (clockid_t clockid, struct timespec *ts)) {
+LLVM_LIBC_FUNCTION(int, clock_gettime, (clockid_t clockid, timespec *ts)) {
   auto result = internal::clock_gettime(clockid, ts);
 
   // A negative return value indicates an error with the magnitude of the
diff --git a/libc/src/time/linux/clock_settime.cpp b/libc/src/time/linux/clock_settime.cpp
new file mode 100644
index 0000000..3c582cf
--- /dev/null
+++ b/libc/src/time/linux/clock_settime.cpp
@@ -0,0 +1,30 @@
+//===---------- Linux implementation of the POSIX clock_settime 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/clock_settime.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/time/clock_settime.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, clock_settime,
+                   (clockid_t clockid, const timespec *ts)) {
+  auto result = internal::clock_settime(clockid, ts);
+
+  // A negative return value indicates an error with the magnitude of the
+  // value being the error code.
+  if (!result.has_value()) {
+    libc_errno = result.error();
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/time/linux/nanosleep.cpp b/libc/src/time/linux/nanosleep.cpp
index e5df158..a30b97d 100644
--- a/libc/src/time/linux/nanosleep.cpp
+++ b/libc/src/time/linux/nanosleep.cpp
@@ -18,8 +18,7 @@
 
 namespace LIBC_NAMESPACE_DECL {
 
-LLVM_LIBC_FUNCTION(int, nanosleep,
-                   (const struct timespec *req, struct timespec *rem)) {
+LLVM_LIBC_FUNCTION(int, nanosleep, (const timespec *req, timespec *rem)) {
 #if SYS_nanosleep
   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_nanosleep, req, rem);
 #elif defined(SYS_clock_nanosleep_time64)
diff --git a/libc/src/time/linux/timespec_get.cpp b/libc/src/time/linux/timespec_get.cpp
index a4d4372..031cb9f 100644
--- a/libc/src/time/linux/timespec_get.cpp
+++ b/libc/src/time/linux/timespec_get.cpp
@@ -15,7 +15,7 @@
 
 namespace LIBC_NAMESPACE_DECL {
 
-LLVM_LIBC_FUNCTION(int, timespec_get, (struct timespec * ts, int base)) {
+LLVM_LIBC_FUNCTION(int, timespec_get, (timespec * ts, int base)) {
   clockid_t clockid;
   switch (base) {
   case TIME_UTC:
diff --git a/libc/src/time/strftime.cpp b/libc/src/time/strftime.cpp
index 89b7d9b..ff8c05a 100644
--- a/libc/src/time/strftime.cpp
+++ b/libc/src/time/strftime.cpp
@@ -23,10 +23,10 @@ LLVM_LIBC_FUNCTION(size_t, strftime,
       printf_core::WriteMode::FILL_BUFF_AND_DROP_OVERFLOW>::value>
       wb(buffer, (buffsz > 0 ? buffsz - 1 : 0));
   printf_core::Writer writer(wb);
-  int ret = strftime_core::strftime_main(&writer, format, timeptr);
+  auto ret = strftime_core::strftime_main(&writer, format, timeptr);
   if (buffsz > 0) // if the buffsz is 0 the buffer may be a null pointer.
     wb.buff[wb.buff_cur] = '\0';
-  return (ret < 0 || static_cast<size_t>(ret) >= buffsz) ? 0 : ret;
+  return (!ret.has_value() || ret.value() >= buffsz) ? 0 : ret.value();
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/time/strftime_core/CMakeLists.txt b/libc/src/time/strftime_core/CMakeLists.txt
index 3ffd283..a9aa573c 100644
--- a/libc/src/time/strftime_core/CMakeLists.txt
+++ b/libc/src/time/strftime_core/CMakeLists.txt
@@ -43,6 +43,7 @@ add_header_library(
     .core_structs
     .parser
     .converter
+    libc.src.__support.error_or
     libc.src.stdio.printf_core.writer
     libc.hdr.types.struct_tm
 )
diff --git a/libc/src/time/strftime_core/strftime_main.h b/libc/src/time/strftime_core/strftime_main.h
index 2b136d8..855a441 100644
--- a/libc/src/time/strftime_core/strftime_main.h
+++ b/libc/src/time/strftime_core/strftime_main.h
@@ -10,6 +10,7 @@
 #define LLVM_LIBC_SRC_STDIO_STRFTIME_CORE_STRFTIME_MAIN_H
 
 #include "hdr/types/struct_tm.h"
+#include "src/__support/error_or.h"
 #include "src/__support/macros/config.h"
 #include "src/stdio/printf_core/writer.h"
 #include "src/time/strftime_core/converter.h"
@@ -20,8 +21,8 @@ namespace LIBC_NAMESPACE_DECL {
 namespace strftime_core {
 
 template <printf_core::WriteMode write_mode>
-int strftime_main(printf_core::Writer<write_mode> *writer,
-                  const char *__restrict str, const tm *timeptr) {
+ErrorOr<size_t> strftime_main(printf_core::Writer<write_mode> *writer,
+                              const char *__restrict str, const tm *timeptr) {
   Parser parser(str);
   int result = 0;
   for (strftime_core::FormatSection cur_section = parser.get_next_section();
@@ -33,11 +34,10 @@ int strftime_main(printf_core::Writer<write_mode> *writer,
       result = writer->write(cur_section.raw_string);
 
     if (result < 0)
-      return result;
+      return Error(-result);
   }
 
-  // TODO: Use ErrorOr<size_t>
-  return static_cast<int>(writer->get_chars_written());
+  return writer->get_chars_written();
 }
 
 } // namespace strftime_core
diff --git a/libc/src/time/strftime_l.cpp b/libc/src/time/strftime_l.cpp
index 409f868..2ec9063 100644
--- a/libc/src/time/strftime_l.cpp
+++ b/libc/src/time/strftime_l.cpp
@@ -26,10 +26,10 @@ LLVM_LIBC_FUNCTION(size_t, strftime_l,
       printf_core::WriteMode::FILL_BUFF_AND_DROP_OVERFLOW>::value>
       wb(buffer, (buffsz > 0 ? buffsz - 1 : 0));
   printf_core::Writer writer(wb);
-  int ret = strftime_core::strftime_main(&writer, format, timeptr);
+  auto ret = strftime_core::strftime_main(&writer, format, timeptr);
   if (buffsz > 0) // if the buffsz is 0 the buffer may be a null pointer.
     wb.buff[wb.buff_cur] = '\0';
-  return (ret < 0 || static_cast<size_t>(ret) >= buffsz) ? 0 : ret;
+  return (!ret.has_value() || ret.value() >= buffsz) ? 0 : ret.value();
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/unistd/CMakeLists.txt b/libc/src/unistd/CMakeLists.txt
index 337480c..b7444a4 100644
--- a/libc/src/unistd/CMakeLists.txt
+++ b/libc/src/unistd/CMakeLists.txt
@@ -77,6 +77,13 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  fchown
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.fchown
+)
+
+add_entrypoint_object(
   fork
   ALIAS
   DEPENDS
diff --git a/libc/src/unistd/fchown.h b/libc/src/unistd/fchown.h
new file mode 100644
index 0000000..9ea4442
--- /dev/null
+++ b/libc/src/unistd/fchown.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for fchown ------------------------*- 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_UNISTD_FCHOWN_H
+#define LLVM_LIBC_SRC_UNISTD_FCHOWN_H
+
+#include "hdr/types/gid_t.h"
+#include "hdr/types/uid_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int fchown(int fildes, uid_t owner, gid_t group);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_UNISTD_FCHOWN_H
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
index c2dacc6..c45b6ef 100644
--- a/libc/src/unistd/linux/CMakeLists.txt
+++ b/libc/src/unistd/linux/CMakeLists.txt
@@ -121,6 +121,20 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  fchown
+  SRCS
+    fchown.cpp
+  HDRS
+    ../fchown.h
+  DEPENDS
+    libc.hdr.types.uid_t
+    libc.hdr.types.gid_t
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
+
+add_entrypoint_object(
   fork
   SRCS
     fork.cpp
diff --git a/libc/src/unistd/linux/fchown.cpp b/libc/src/unistd/linux/fchown.cpp
new file mode 100644
index 0000000..9cf3d13
--- /dev/null
+++ b/libc/src/unistd/linux/fchown.cpp
@@ -0,0 +1,31 @@
+//===-- Linux implementation of fchown ------------------------------------===//
+//
+// 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/unistd/fchown.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+
+#include "hdr/types/gid_t.h"
+#include "hdr/types/uid_t.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, fchown, (int fildes, uid_t owner, gid_t group)) {
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_fchown, fildes, owner, group);
+  if (ret < 0) {
+    libc_errno = -ret;
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL