[libc][NFC] Port raw syscall users to existing syscall_wrappers (#208039)

Several call sites still invoked syscall_impl directly (or carried
their own SYS_* fallback ladders) for syscalls that already have a
wrapper in src/__support/OSUtil/linux/syscall_wrappers.

This PR removes these syscalls in favor of the syscall_wrappers.

libc/src/__support/File/linux/CMakeLists.txt

@@ -11,12 +11,13 @@ add_object_library(
     libc.hdr.sys_stat_macros
     libc.hdr.types.FILE
     libc.hdr.types.off_t
-    libc.include.sys_syscall
     libc.src.__support.CPP.new
-    libc.src.__support.OSUtil.osutil
+    libc.src.__support.OSUtil.linux.syscall_wrappers.close
     libc.src.__support.OSUtil.linux.syscall_wrappers.fcntl
     libc.src.__support.OSUtil.linux.syscall_wrappers.lseek
     libc.src.__support.OSUtil.linux.syscall_wrappers.open
+    libc.src.__support.OSUtil.linux.syscall_wrappers.read
+    libc.src.__support.OSUtil.linux.syscall_wrappers.write
     libc.src.__support.error_or
     libc.src.__support.File.file
     libc.src.errno.errno
@@ -33,6 +34,7 @@ add_object_library(
     libc.hdr.sys_stat_macros
     libc.src.__support.OSUtil.linux.stat.kernel_statx_types
     libc.src.__support.OSUtil.osutil
+    libc.src.__support.OSUtil.linux.syscall_wrappers.close
     libc.src.__support.OSUtil.linux.syscall_wrappers.open
     libc.src.__support.OSUtil.linux.syscall_wrappers.fcntl
     libc.src.__support.OSUtil.linux.syscall_wrappers.statx

libc/src/__support/File/linux/dir.cpp

@@ -15,6 +15,7 @@
 #include "hdr/fcntl_macros.h"    // For open flags
 #include "hdr/sys_stat_macros.h" // For S_ISDIR
 #include "src/__support/OSUtil/linux/stat/kernel_statx_types.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/close.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/fcntl.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/open.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/statx.h"
@@ -42,9 +43,9 @@ ErrorOr<size_t> platform_fetch_dirents(int fd, cpp::span<uint8_t> buffer) {
 }
 
 int platform_closedir(int fd) {
-  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_close, fd);
-  if (ret < 0)
-    return static_cast<int>(-ret);
+  auto ret = linux_syscalls::close(fd);
+  if (!ret)
+    return ret.error();
   return 0;
 }
 

libc/src/__support/File/linux/file.cpp

@@ -14,36 +14,34 @@
 #include "hdr/types/off_t.h"
 #include "src/__support/CPP/new.h"
 #include "src/__support/File/file.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/close.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/fcntl.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/lseek.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/open.h"
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/OSUtil/linux/syscall_wrappers/read.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/write.h"
 #include "src/__support/alloc-checker.h"
 #include "src/__support/libc_errno.h" // For error macros
 #include "src/__support/macros/config.h"
 
-#include <sys/syscall.h>      // For syscall numbers
-
 namespace LIBC_NAMESPACE_DECL {
 
 FileIOResult linux_file_write(File *f, const void *data, size_t size) {
   auto *lf = reinterpret_cast<LinuxFile *>(f);
-  int ret =
-      LIBC_NAMESPACE::syscall_impl<int>(SYS_write, lf->get_fd(), data, size);
-  if (ret < 0) {
-    return {0, -ret};
+  auto ret = linux_syscalls::write(lf->get_fd(), data, size);
+  if (!ret) {
+    return {0, ret.error()};
   }
-  return ret;
+  return static_cast<size_t>(ret.value());
 }
 
 FileIOResult linux_file_read(File *f, void *buf, size_t size) {
   auto *lf = reinterpret_cast<LinuxFile *>(f);
-  int ret =
-      LIBC_NAMESPACE::syscall_impl<int>(SYS_read, lf->get_fd(), buf, size);
-  if (ret < 0) {
-    return {0, -ret};
+  auto ret = linux_syscalls::read(lf->get_fd(), buf, size);
+  if (!ret) {
+    return {0, ret.error()};
   }
-  return ret;
+  return static_cast<size_t>(ret.value());
 }
 
 ErrorOr<off_t> linux_file_seek(File *f, off_t offset, int whence) {
@@ -54,9 +52,9 @@ ErrorOr<off_t> linux_file_seek(File *f, off_t offset, int whence) {
 int linux_file_close(File *f) {
   File::remove_file(f);
   auto *lf = reinterpret_cast<LinuxFile *>(f);
-  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_close, lf->get_fd());
-  if (ret < 0) {
-    return -ret;
+  auto ret = linux_syscalls::close(lf->get_fd());
+  if (!ret) {
+    return ret.error();
   }
   delete lf;
   return 0;

libc/src/__support/OSUtil/linux/CMakeLists.txt

@@ -25,12 +25,15 @@ add_header_library(
   HDRS
     auxv.h
   DEPENDS
+    libc.hdr.errno_macros
     libc.hdr.fcntl_macros
     libc.hdr.sys_auxv_macros
     libc.hdr.sys_mman_macros
+    libc.src.__support.OSUtil.linux.syscall_wrappers.close
     libc.src.__support.OSUtil.linux.syscall_wrappers.mmap
     libc.src.__support.OSUtil.linux.syscall_wrappers.munmap
     libc.src.__support.OSUtil.linux.syscall_wrappers.open
+    libc.src.__support.OSUtil.linux.syscall_wrappers.read
     libc.src.__support.OSUtil.osutil
     libc.src.__support.common
     libc.src.__support.CPP.optional

libc/src/__support/OSUtil/linux/auxv.h

@@ -9,12 +9,15 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_AUXV_H
 #define LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_AUXV_H
 
+#include "hdr/errno_macros.h"    // For EINTR
 #include "hdr/fcntl_macros.h"    // For open flags
 #include "hdr/sys_auxv_macros.h" // For AT_ macros
 #include "hdr/sys_mman_macros.h" // For mmap flags
+#include "src/__support/OSUtil/linux/syscall_wrappers/close.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/mmap.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/munmap.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/open.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/read.h"
 #include "src/__support/OSUtil/syscall.h"
 #include "src/__support/common.h"
 #include "src/__support/threads/callonce.h"
@@ -122,18 +125,20 @@ LIBC_INLINE void Vector::fallback_initialize_unsync() {
   uint8_t *cursor = reinterpret_cast<uint8_t *>(vector);
   bool has_error = false;
   while (avaiable_size != 0) {
-    long bytes_read =
-        syscall_impl<long>(SYS_read, fd.value(), cursor, avaiable_size);
-    if (bytes_read <= 0) {
-      if (bytes_read == -EINTR)
+    ErrorOr<ssize_t> bytes_read =
+        linux_syscalls::read(fd.value(), cursor, avaiable_size);
+    if (!bytes_read.has_value()) {
+      if (bytes_read.error() == EINTR)
         continue;
-      has_error = bytes_read < 0;
+      has_error = true;
       break;
     }
-    avaiable_size -= bytes_read;
-    cursor += bytes_read;
+    if (bytes_read.value() == 0)
+      break;
+    avaiable_size -= bytes_read.value();
+    cursor += bytes_read.value();
   }
-  syscall_impl<long>(SYS_close, fd.value());
+  linux_syscalls::close(fd.value());
   if (has_error) {
     linux_syscalls::munmap(vector, AUXV_MMAP_SIZE);
     return;

libc/src/__support/threads/linux/CMakeLists.txt

@@ -41,10 +41,13 @@ add_object_library(
     libc.src.__support.CPP.string_view
     libc.src.__support.common
     libc.src.__support.error_or
+    libc.src.__support.OSUtil.linux.syscall_wrappers.close
     libc.src.__support.OSUtil.linux.syscall_wrappers.mmap
     libc.src.__support.OSUtil.linux.syscall_wrappers.mprotect
     libc.src.__support.OSUtil.linux.syscall_wrappers.munmap
     libc.src.__support.OSUtil.linux.syscall_wrappers.open
+    libc.src.__support.OSUtil.linux.syscall_wrappers.read
+    libc.src.__support.OSUtil.linux.syscall_wrappers.write
     libc.src.__support.threads.thread_common
   COMPILE_OPTIONS
     ${libc_opt_high_flag}

libc/src/__support/threads/linux/thread.cpp

@@ -11,10 +11,13 @@
 #include "src/__support/CPP/atomic.h"
 #include "src/__support/CPP/string_view.h"
 #include "src/__support/CPP/stringstream.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/close.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/mmap.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/mprotect.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/munmap.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/open.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/read.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/write.h"
 #include "src/__support/OSUtil/syscall.h" // For syscall functions.
 #include "src/__support/common.h"
 #include "src/__support/error_or.h"
@@ -435,13 +438,13 @@ int Thread::set_name(const cpp::string_view &name) {
   if (!fd)
     return fd.error();
 
-  int retval = LIBC_NAMESPACE::syscall_impl<int>(SYS_write, fd.value(),
-                                                 name.data(), name.size());
-  LIBC_NAMESPACE::syscall_impl<long>(SYS_close, fd.value());
+  auto write_result =
+      linux_syscalls::write(fd.value(), name.data(), name.size());
+  linux_syscalls::close(fd.value());
 
-  if (retval < 0)
-    return -retval;
-  else if (retval != int(name.size()))
+  if (!write_result)
+    return write_result.error();
+  else if (write_result.value() != static_cast<ssize_t>(name.size()))
     return EIO;
   else
     return 0;
@@ -471,11 +474,12 @@ int Thread::get_name(cpp::StringStream &name) const {
   if (!fd)
     return fd.error();
 
-  int retval = LIBC_NAMESPACE::syscall_impl<int>(SYS_read, fd.value(),
-                                                 name_buffer, NAME_SIZE_MAX);
-  LIBC_NAMESPACE::syscall_impl<long>(SYS_close, fd.value());
-  if (retval < 0)
-    return -retval;
+  auto read_result =
+      linux_syscalls::read(fd.value(), name_buffer, NAME_SIZE_MAX);
+  linux_syscalls::close(fd.value());
+  if (!read_result)
+    return read_result.error();
+  int retval = static_cast<int>(read_result.value());
   if (retval == NAME_SIZE_MAX)
     return ERANGE;
   if (name_buffer[retval - 1] == '\n')

libc/src/sched/linux/CMakeLists.txt

@@ -20,7 +20,8 @@ add_entrypoint_object(
     libc.hdr.types.cpu_set_t
     libc.hdr.types.pid_t
     libc.hdr.types.size_t
-    libc.src.__support.OSUtil.osutil
+    libc.src.__support.CPP.span
+    libc.src.__support.OSUtil.linux.syscall_wrappers.sched_getaffinity
     libc.src.errno.errno
 )
 

libc/src/sched/linux/sched_getaffinity.cpp

@@ -9,7 +9,8 @@
 #include "src/sched/sched_getaffinity.h"
 
 #include "hdr/stdint_proxy.h"
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/CPP/span.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/sched_getaffinity.h"
 #include "src/__support/common.h"
 #include "src/__support/libc_errno.h"
 #include "src/__support/macros/config.h"
@@ -17,18 +18,19 @@
 #include "hdr/types/cpu_set_t.h"
 #include "hdr/types/pid_t.h"
 #include "hdr/types/size_t.h"
-#include <sys/syscall.h> // For syscall numbers.
 
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, sched_getaffinity,
                    (pid_t tid, size_t cpuset_size, cpu_set_t *mask)) {
-  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_sched_getaffinity, tid,
-                                              cpuset_size, mask);
-  if (ret < 0) {
-    libc_errno = -ret;
+  auto result = linux_syscalls::sched_getaffinity(
+      tid, cpp::span<unsigned char>(reinterpret_cast<unsigned char *>(mask),
+                                    cpuset_size));
+  if (!result) {
+    libc_errno = result.error();
     return -1;
   }
+  int ret = result.value();
   if (size_t(ret) < cpuset_size) {
     // This means that only |ret| bytes in |mask| have been set. We will have to
     // zero out the remaining bytes.

libc/src/spawn/linux/CMakeLists.txt

@@ -11,6 +11,7 @@ add_entrypoint_object(
     libc.include.spawn
     libc.include.sys_syscall
     libc.src.__support.OSUtil.osutil
+    libc.src.__support.OSUtil.linux.syscall_wrappers.close
     libc.src.__support.OSUtil.linux.syscall_wrappers.dup2
     libc.src.__support.OSUtil.linux.syscall_wrappers.open
     libc.src.spawn.file_actions

libc/src/spawn/linux/posix_spawn.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/spawn/posix_spawn.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/close.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/dup2.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/open.h"
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
@@ -40,8 +41,6 @@ pid_t fork() {
 #endif
 }
 
-void close(int fd) { LIBC_NAMESPACE::syscall_impl<long>(SYS_close, fd); }
-
 // All exits from child_process are error exits. So, we use a simple
 // exit implementation which exits with code 127.
 void exit() {
@@ -75,7 +74,7 @@ void child_process(const char *__restrict path,
         if (actual_fd != open_act->fd) {
           bool dup2_result =
               linux_syscalls::dup2(actual_fd, open_act->fd).has_value();
-          close(actual_fd); // The old fd is not needed anymore.
+          linux_syscalls::close(actual_fd); // The old fd is not needed anymore.
           if (!dup2_result)
             exit();
         }
@@ -83,7 +82,7 @@ void child_process(const char *__restrict path,
       }
       case BaseSpawnFileAction::CLOSE: {
         auto *close_act = reinterpret_cast<SpawnFileCloseAction *>(act);
-        close(close_act->fd);
+        linux_syscalls::close(close_act->fd);
         break;
       }
       case BaseSpawnFileAction::DUP2: {

libc/src/stdio/linux/CMakeLists.txt

@@ -5,10 +5,10 @@ add_entrypoint_object(
   HDRS
     ../remove.h
   DEPENDS
+    libc.hdr.errno_macros
     libc.hdr.fcntl_macros
     libc.include.unistd
-    libc.include.sys_syscall
-    libc.src.__support.OSUtil.osutil
+    libc.src.__support.OSUtil.linux.syscall_wrappers.unlinkat
     libc.src.errno.errno
 )
 

libc/src/stdio/linux/remove.cpp

@@ -8,26 +8,25 @@
 
 #include "src/stdio/remove.h"
 
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/OSUtil/linux/syscall_wrappers/unlinkat.h"
 #include "src/__support/common.h"
 
+#include "hdr/errno_macros.h" // For EISDIR.
 #include "hdr/fcntl_macros.h" // For AT_* macros.
 #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, remove, (const char *path)) {
   // We first try unlinking it as a file. If it is ia file, it will succeed. If
   // it fails with EISDIR, we will try unlinking it as a directory.
-  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_unlinkat, AT_FDCWD, path, 0);
-  if (ret == -EISDIR)
-    ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_unlinkat, AT_FDCWD, path,
-                                            AT_REMOVEDIR);
-  if (ret >= 0)
+  auto ret = linux_syscalls::unlinkat(AT_FDCWD, path, 0);
+  if (!ret && ret.error() == EISDIR)
+    ret = linux_syscalls::unlinkat(AT_FDCWD, path, AT_REMOVEDIR);
+  if (ret)
     return 0;
-  libc_errno = -ret;
+  libc_errno = ret.error();
   return -1;
 }
 

libc/src/sys/ipc/linux/CMakeLists.txt

@@ -1,14 +1,3 @@
-add_header_library(
-  kernel_statx
-  HDRS
-    kernel_statx.h
-  DEPENDS
-    libc.hdr.fcntl_macros
-    libc.include.sys_syscall
-    libc.src.__support.error_or
-    libc.src.__support.OSUtil.osutil
-)
-
 add_entrypoint_object(
   ftok
   SRCS
@@ -16,8 +5,10 @@ add_entrypoint_object(
   HDRS
     ../ftok.h
   DEPENDS
-    .kernel_statx
+    libc.hdr.fcntl_macros
     libc.hdr.types.key_t
+    libc.src.__support.OSUtil.linux.stat.kernel_statx_types
+    libc.src.__support.OSUtil.linux.syscall_wrappers.statx
     libc.src.__support.common
     libc.src.errno.errno
 )

libc/src/sys/ipc/linux/ftok.cpp

@@ -7,18 +7,19 @@
 //===----------------------------------------------------------------------===//
 #include "src/sys/ipc/ftok.h"
 
+#include "hdr/fcntl_macros.h" // For AT_FDCWD.
+#include "src/__support/OSUtil/linux/stat/kernel_statx_types.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/statx.h"
 #include "src/__support/common.h"
-#include "src/__support/error_or.h"
 #include "src/__support/libc_errno.h"
 
-#include "kernel_statx.h"
-
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(key_t, ftok, (const char *path, int id)) {
-  struct statx xbuf;
+  internal::kernel_statx_buf xbuf;
 
-  ErrorOr<int> err = statx_for_ftok(path, xbuf);
+  auto err = linux_syscalls::statx(
+      AT_FDCWD, path, 0, internal::KERNEL_STATX_BASIC_STATS_MASK, &xbuf);
 
   if (!err.has_value()) {
     libc_errno = err.error();

libc/src/sys/ipc/linux/kernel_statx.h

@@ -1,34 +0,0 @@
-//===-- Wrapper over SYS_statx syscall for ftok ---------------------------===//
-//
-// 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_SYS_IPC_LINUX_KERNEL_STATX_H
-#define LLVM_LIBC_SRC_SYS_IPC_LINUX_KERNEL_STATX_H
-
-#include "hdr/fcntl_macros.h"
-#include "src/__support/OSUtil/syscall.h"
-#include "src/__support/error_or.h"
-#include "sys/syscall.h"
-
-#include <linux/stat.h>
-
-namespace LIBC_NAMESPACE_DECL {
-
-LIBC_INLINE ErrorOr<int> statx_for_ftok(const char *path, struct statx &xbuf) {
-
-  // store the file stats metadata into xbuf
-  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_statx, AT_FDCWD, path, 0,
-                                              STATX_BASIC_STATS, &xbuf);
-
-  if (ret < 0)
-    return Error(-ret);
-  return 0;
-}
-
-} // namespace LIBC_NAMESPACE_DECL
-
-#endif // LLVM_LIBC_SRC_SYS_IPC_LINUX_KERNEL_STATX_H

libc/src/sys/mman/linux/CMakeLists.txt

@@ -306,6 +306,7 @@ add_entrypoint_object(
   HDRS
     ../shm_unlink.h
   DEPENDS
+    libc.src.__support.OSUtil.linux.syscall_wrappers.unlink
     libc.src.errno.errno
     .shm_common
 )

libc/src/sys/mman/linux/shm_unlink.cpp

@@ -8,37 +8,26 @@
 
 #include "src/sys/mman/shm_unlink.h"
 
-#include "hdr/fcntl_macros.h"
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
-#include "src/__support/libc_errno.h"     // For internal errno.
+#include "src/__support/OSUtil/linux/syscall_wrappers/unlink.h"
+#include "src/__support/libc_errno.h" // For internal errno.
 #include "src/__support/macros/config.h"
 #include "src/sys/mman/linux/shm_common.h"
-#include <sys/syscall.h> // For SYS_unlink, SYS_unlinkat
 
 namespace LIBC_NAMESPACE_DECL {
 
-// TODO: move the unlink syscall to a shared utility.
-
 LLVM_LIBC_FUNCTION(int, shm_unlink, (const char *name)) {
   auto path_result = shm_common::translate_name(name);
   if (!path_result.has_value()) {
     libc_errno = path_result.error();
     return -1;
   }
-#ifdef SYS_unlink
-  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_unlink, path_result->data());
-#elif defined(SYS_unlinkat)
-  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_unlinkat, AT_FDCWD,
-                                              path_result->data(), 0);
-#else
-#error "unlink and unlinkat syscalls not available."
-#endif
 
-  if (ret < 0) {
-    libc_errno = -ret;
+  auto result = linux_syscalls::unlink(path_result->data());
+  if (!result) {
+    libc_errno = result.error();
     return -1;
   }
-  return ret;
+  return 0;
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/sys/time/linux/CMakeLists.txt

@@ -8,10 +8,8 @@ add_entrypoint_object(
     libc.hdr.types.struct_timespec
     libc.hdr.types.struct_timeval
     libc.hdr.fcntl_macros
-    libc.src.__support.OSUtil.osutil
     libc.src.__support.OSUtil.linux.syscall_wrappers.utimensat
     libc.include.sys_stat
-    libc.include.sys_syscall
     libc.include.fcntl
     libc.src.__support.libc_errno
 )

libc/src/sys/time/linux/utimes.cpp

@@ -13,17 +13,12 @@
 #include "hdr/types/struct_timeval.h"
 
 #include "src/__support/OSUtil/linux/syscall_wrappers/utimensat.h"
-#include "src/__support/OSUtil/syscall.h"
 #include "src/__support/libc_errno.h"
 
-#include <sys/syscall.h>
-
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, utimes,
                    (const char *path, const struct timeval times[2])) {
-#if defined(SYS_utimensat) || defined(SYS_utimensat_time64)
-
   // the utimensat syscall requires a timespec struct, not timeval.
   struct timespec ts[2];
   struct timespec *ts_ptr = nullptr; // default value if times is nullptr
@@ -64,8 +59,5 @@ LLVM_LIBC_FUNCTION(int, utimes,
   }
 
   return 0;
-#else
-#error "utimensat or utimensat_time64 syscalls not available."
-#endif // SYS_utimensat || SYS_utimensat_time64
 }
 } // namespace LIBC_NAMESPACE_DECL

libc/startup/linux/x86_64/CMakeLists.txt

@@ -7,6 +7,7 @@ add_startup_object(
     libc.hdr.sys_mman_macros
     libc.include.sys_syscall
     libc.src.__support.OSUtil.osutil
+    libc.src.__support.OSUtil.linux.syscall_wrappers.getrandom
     libc.src.__support.OSUtil.linux.syscall_wrappers.mmap
     libc.src.__support.OSUtil.linux.syscall_wrappers.munmap
     libc.src.string.memory_utils.inline_memcpy

libc/startup/linux/x86_64/tls.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "hdr/sys_mman_macros.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/getrandom.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/mmap.h"
 #include "src/__support/OSUtil/linux/syscall_wrappers/munmap.h"
 #include "src/__support/macros/config.h"
@@ -57,11 +58,11 @@ void init_tls(TLSDescriptor &tls_descriptor) {
   // Setting the stack guard to a random value.
   // We cannot call the get_random function here as the function sets errno on
   // failure. Since errno is implemented via a thread local variable, we cannot
-  // use errno before TLS is setup.
-  long stack_guard_retval =
-      syscall_impl(SYS_getrandom, reinterpret_cast<long>(stack_guard_addr),
-                   sizeof(uint64_t), 0);
-  if (stack_guard_retval < 0)
+  // use errno before TLS is setup. The linux_syscalls wrapper is safe as it
+  // reports errors via ErrorOr instead of errno.
+  ErrorOr<ssize_t> stack_guard_retval =
+      linux_syscalls::getrandom(stack_guard_addr, sizeof(uint64_t), 0);
+  if (!stack_guard_retval.has_value())
     syscall_impl(SYS_exit, 1);
 
   tls_descriptor = {tls_size_with_addr, reinterpret_cast<uintptr_t>(tls_addr),

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -1603,10 +1603,12 @@ libc_support_library(
         ":__support_file_file",
         ":__support_libc_errno",
         ":__support_macros_config",
+        ":__support_osutil_linux_syscall_wrappers_close",
         ":__support_osutil_linux_syscall_wrappers_fcntl",
         ":__support_osutil_linux_syscall_wrappers_lseek",
         ":__support_osutil_linux_syscall_wrappers_open",
-        ":__support_osutil_syscall",
+        ":__support_osutil_linux_syscall_wrappers_read",
+        ":__support_osutil_linux_syscall_wrappers_write",
         ":hdr_fcntl_macros",
         ":hdr_stdint_proxy",
         ":hdr_stdio_macros",
@@ -2932,11 +2934,14 @@ libc_support_library(
     }),
     deps = [
         ":__support_common",
+        ":__support_osutil_linux_syscall_wrappers_close",
         ":__support_osutil_linux_syscall_wrappers_mmap",
         ":__support_osutil_linux_syscall_wrappers_munmap",
         ":__support_osutil_linux_syscall_wrappers_open",
+        ":__support_osutil_linux_syscall_wrappers_read",
         ":__support_osutil_syscall",
         ":__support_threads_callonce",
+        ":hdr_errno_macros",
         ":hdr_fcntl_macros",
         ":hdr_sys_auxv_macros",
         ":hdr_sys_mman_macros",
@@ -15702,8 +15707,9 @@ libc_function(
         ":__support_common",
         ":__support_libc_errno",
         ":__support_macros_config",
-        ":__support_osutil_syscall",
+        ":__support_osutil_linux_syscall_wrappers_unlinkat",
         ":errno",
+        ":hdr_errno_macros",
         ":hdr_fcntl_macros",
         ":hdr_stdio_overlay",
         ":types_FILE",
@@ -16090,9 +16096,8 @@ libc_function(
         ":__support_common",
         ":__support_libc_errno",
         ":__support_macros_config",
-        ":__support_osutil_syscall",
+        ":__support_osutil_linux_syscall_wrappers_unlink",
         ":errno",
-        ":hdr_fcntl_macros",
         ":shm_common",
         ":types_mode_t",
     ],