| 1 | //===-- Linux implementation of ftruncate ---------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "src/unistd/ftruncate.h" |
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| 10 | |
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| 11 | #include "src/__support/OSUtil/syscall.h" // For internal syscall function. |
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| 12 | #include "src/__support/common.h" |
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| 13 | |
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| 14 | #include "src/errno/libc_errno.h" |
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| 15 | #include <stdint.h> // For uint64_t. |
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| 16 | #include <sys/syscall.h> // For syscall numbers. |
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| 17 | #include <unistd.h> |
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| 18 | |
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| 19 | namespace LIBC_NAMESPACE { |
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| 20 | |
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| 21 | LLVM_LIBC_FUNCTION(int, ftruncate, (int fd, off_t len)) { |
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| 22 | #ifdef SYS_ftruncate |
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| 23 | int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_ftruncate, ts: fd, ts: len); |
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| 24 | #elif defined(SYS_ftruncate64) |
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| 25 | // Same as ftruncate but can handle large offsets |
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| 26 | static_assert(sizeof(off_t) == 8); |
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| 27 | int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_ftruncate64, fd, (long)len, |
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| 28 | (long)(((uint64_t)(len)) >> 32)); |
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| 29 | #else |
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| 30 | #error "ftruncate and ftruncate64 syscalls not available." |
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| 31 | #endif |
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| 32 | |
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| 33 | if (ret < 0) { |
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| 34 | libc_errno = -ret; |
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| 35 | return -1; |
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| 36 | } |
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| 37 | return 0; |
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| 38 | } |
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| 39 | |
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| 40 | } // namespace LIBC_NAMESPACE |
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| 41 | |
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