1//===-- Linux implementation of truncate ----------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/unistd/truncate.h"
10
11#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
12#include "src/__support/common.h"
13#include "src/errno/libc_errno.h"
14
15#include <stdint.h> // For uint64_t.
16#include <sys/syscall.h> // For syscall numbers.
17#include <unistd.h>
18
19namespace LIBC_NAMESPACE {
20
21LLVM_LIBC_FUNCTION(int, truncate, (const char *path, off_t len)) {
22#ifdef SYS_truncate
23 int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_truncate, ts: path, ts: len);
24#elif defined(SYS_truncate64)
25 // Same as truncate but can handle large offsets
26 static_assert(sizeof(off_t) == 8);
27 int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_truncate64, path, (long)len,
28 (long)(((uint64_t)(len)) >> 32));
29#else
30#error "truncate and truncate64 syscalls not available."
31#endif
32 if (ret < 0) {
33 libc_errno = -ret;
34 return -1;
35 }
36 return 0;
37}
38
39} // namespace LIBC_NAMESPACE
40

source code of libc/src/unistd/linux/truncate.cpp