xref: /aosp_15_r20/external/llvm-libc/src/fcntl/linux/open.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Implementation of open --------------------------------------------===//
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/fcntl/open.h"
10 
11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
12 #include "src/__support/common.h"
13 #include "src/__support/macros/config.h"
14 #include "src/errno/libc_errno.h"
15 
16 #include "hdr/fcntl_macros.h"
17 #include "hdr/types/mode_t.h"
18 #include <stdarg.h>
19 #include <sys/syscall.h> // For syscall numbers.
20 
21 namespace LIBC_NAMESPACE_DECL {
22 
23 LLVM_LIBC_FUNCTION(int, open, (const char *path, int flags, ...)) {
24   mode_t mode_flags = 0;
25   // O_TMPFILE is a multi-bit flag so we test all bits by checking for equality
26   // with O_TMPFILE
27   if ((flags & O_CREAT) || (flags & O_TMPFILE) == O_TMPFILE) {
28     va_list varargs;
29     va_start(varargs, flags);
30     mode_flags = va_arg(varargs, mode_t);
31     va_end(varargs);
32   }
33 
34 #ifdef SYS_open
35   int fd = LIBC_NAMESPACE::syscall_impl<int>(SYS_open, path, flags, mode_flags);
36 #else
37   int fd = LIBC_NAMESPACE::syscall_impl<int>(SYS_openat, AT_FDCWD, path, flags,
38                                              mode_flags);
39 #endif
40   if (fd > 0)
41     return fd;
42 
43   libc_errno = -fd;
44   return -1;
45 }
46 
47 } // namespace LIBC_NAMESPACE_DECL
48