[libc-commits] [libc] 8cd4ecf - [libc] Unify lseek implementations
Mikhail R. Gadelha via libc-commits
libc-commits at lists.llvm.org
Wed Sep 6 07:56:51 PDT 2023
Author: Mikhail R. Gadelha
Date: 2023-09-06T11:56:41-03:00
New Revision: 8cd4ecfa6001eed7486fa3618bbd6bde47a0b075
URL: https://github.com/llvm/llvm-project/commit/8cd4ecfa6001eed7486fa3618bbd6bde47a0b075
DIFF: https://github.com/llvm/llvm-project/commit/8cd4ecfa6001eed7486fa3618bbd6bde47a0b075.diff
LOG: [libc] Unify lseek implementations
In patch D157792, the calls to SYS_llseek/SYS_llseek for 32-bit systems
were fixed in lseek.cpp but there was another implementation in file.cpp
that was missed.
To reduce the code duplication, this patch unifies both call sites to
use a new lseekimpl function.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D159208
Added:
libc/src/__support/File/linux/lseekImpl.h
Modified:
libc/src/__support/File/linux/file.cpp
libc/src/unistd/linux/lseek.cpp
Removed:
################################################################################
diff --git a/libc/src/__support/File/linux/file.cpp b/libc/src/__support/File/linux/file.cpp
index 611d45ea7ac4d61..2d4481bc4b56370 100644
--- a/libc/src/__support/File/linux/file.cpp
+++ b/libc/src/__support/File/linux/file.cpp
@@ -11,6 +11,7 @@
#include "src/__support/File/file.h"
#include "src/__support/CPP/new.h"
+#include "src/__support/File/linux/lseekImpl.h"
#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
#include "src/errno/libc_errno.h" // For error macros
@@ -40,32 +41,10 @@ FileIOResult linux_file_read(File *f, void *buf, size_t size) {
ErrorOr<long> linux_file_seek(File *f, long offset, int whence) {
auto *lf = reinterpret_cast<LinuxFile *>(f);
- long result;
-#ifdef SYS_lseek
- int ret =
- __llvm_libc::syscall_impl<int>(SYS_lseek, lf->get_fd(), offset, whence);
- result = ret;
-#elif defined(SYS_llseek)
- int ret = __llvm_libc::syscall_impl<int>(SYS_llseek, lf->get_fd(),
- (long)(((uint64_t)(offset)) >> 32),
- (long)offset, &result, whence);
- result = ret;
-#elif defined(SYS_llseek)
- int ret = __llvm_libc::syscall_impl<int>(SYS_llseek, lf->get_fd(),
- (long)(((uint64_t)(offset)) >> 32),
- (long)offset, &result, whence);
- result = ret;
-#elif defined(SYS__llseek)
- int ret = __llvm_libc::syscall_impl<int>(
- SYS__llseek, lf->get_fd(), offset >> 32, offset, &result, whence);
-#else
-#error "lseek, llseek and _llseek syscalls not available."
-#endif
-
- if (ret < 0)
- return Error(-ret);
-
- return result;
+ auto result = internal::lseekimpl(lf->get_fd(), offset, whence);
+ if (!result.has_value())
+ return result.error();
+ return result.value();
}
int linux_file_close(File *f) {
diff --git a/libc/src/__support/File/linux/lseekImpl.h b/libc/src/__support/File/linux/lseekImpl.h
new file mode 100644
index 000000000000000..8594cd3536fcdca
--- /dev/null
+++ b/libc/src/__support/File/linux/lseekImpl.h
@@ -0,0 +1,50 @@
+//===-- Linux implementation of lseek -------------------------------------===//
+//
+// 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_FILE_LINUX_LSEEKIMPL_H
+#define LLVM_LIBC_SRC_SUPPORT_FILE_LINUX_LSEEKIMPL_H
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/errno/libc_errno.h"
+
+#include <stdint.h> // For uint64_t.
+#include <sys/syscall.h> // For syscall numbers.
+#include <unistd.h> // For off_t.
+
+namespace __llvm_libc {
+namespace internal {
+
+LIBC_INLINE ErrorOr<off_t> lseekimpl(int fd, off_t offset, int whence) {
+ off_t result;
+#ifdef SYS_lseek
+ int ret = __llvm_libc::syscall_impl<int>(SYS_lseek, fd, offset, whence);
+ result = ret;
+#elif defined(SYS_llseek) || defined(SYS__llseek)
+ static_assert(sizeof(size_t) == 4, "size_t must be 32 bits.");
+#ifdef SYS_llseek
+ constexpr long LLSEEK_SYSCALL_NO = SYS_llseek;
+#elif defined(SYS__llseek)
+ constexpr long LLSEEK_SYSCALL_NO = SYS__llseek;
+#endif
+ off_t offset_64 = offset;
+ int ret = __llvm_libc::syscall_impl<int>(
+ LLSEEK_SYSCALL_NO, fd, offset_64 >> 32, offset_64, &result, whence);
+#else
+#error "lseek, llseek and _llseek syscalls not available."
+#endif
+ if (ret < 0)
+ return Error(-ret);
+ return result;
+}
+
+} // namespace internal
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_SUPPORT_FILE_LINUX_LSEEKIMPL_H
diff --git a/libc/src/unistd/linux/lseek.cpp b/libc/src/unistd/linux/lseek.cpp
index 87900e2f8c08f50..3ab0084269e2db9 100644
--- a/libc/src/unistd/linux/lseek.cpp
+++ b/libc/src/unistd/linux/lseek.cpp
@@ -9,38 +9,22 @@
#include "src/unistd/lseek.h"
#include "src/errno/libc_errno.h"
+#include "src/__support/File/linux/lseekImpl.h"
#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
#include "src/__support/common.h"
-#include <stdint.h>
#include <sys/syscall.h> // For syscall numbers.
-#include <unistd.h>
+#include <unistd.h> // For off_t.
namespace __llvm_libc {
LLVM_LIBC_FUNCTION(off_t, lseek, (int fd, off_t offset, int whence)) {
- off_t result;
-#ifdef SYS_lseek
- int ret = __llvm_libc::syscall_impl<int>(SYS_lseek, fd, offset, whence);
- result = ret;
-#elif defined(SYS_llseek) || defined(SYS__llseek)
-#ifdef SYS_llseek
- constexpr long LLSEEK_SYSCALL_NO = SYS_llseek;
-#elif defined(SYS__llseek)
- constexpr long LLSEEK_SYSCALL_NO = SYS__llseek;
-#endif
- uint64_t offset_64 = static_cast<uint64_t>(offset);
- int ret = __llvm_libc::syscall_impl<int>(
- LLSEEK_SYSCALL_NO, fd, offset_64 >> 32, offset_64, &result, whence);
-#else
-#error "lseek, llseek and _llseek syscalls not available."
-#endif
-
- if (ret < 0) {
- libc_errno = -ret;
+ auto result = internal::lseekimpl(fd, offset, whence);
+ if (!result.has_value()) {
+ libc_errno = result.error();
return -1;
}
- return result;
+ return result.value();
}
} // namespace __llvm_libc
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