xref: /llvm-project/libc/src/fcntl/linux/open.cpp (revision 5ff3ff33ff930e4ec49da7910612d8a41eb068cb)
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 <fcntl.h>
17 #include <stdarg.h>
18 #include <sys/syscall.h> // For syscall numbers.
19 
20 namespace LIBC_NAMESPACE_DECL {
21 
22 LLVM_LIBC_FUNCTION(int, open, (const char *path, int flags, ...)) {
23   mode_t mode_flags = 0;
24   // O_TMPFILE is a multi-bit flag so we test all bits by checking for equality
25   // with O_TMPFILE
26   if ((flags & O_CREAT) || (flags & O_TMPFILE) == O_TMPFILE) {
27     va_list varargs;
28     va_start(varargs, flags);
29     mode_flags = va_arg(varargs, mode_t);
30     va_end(varargs);
31   }
32 
33 #ifdef SYS_open
34   int fd = LIBC_NAMESPACE::syscall_impl<int>(SYS_open, path, flags, mode_flags);
35 #else
36   int fd = LIBC_NAMESPACE::syscall_impl<int>(SYS_openat, AT_FDCWD, path, flags,
37                                              mode_flags);
38 #endif
39   if (fd > 0)
40     return fd;
41 
42   libc_errno = -fd;
43   return -1;
44 }
45 
46 } // namespace LIBC_NAMESPACE_DECL
47