/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :viâ
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â Copyright 2021 Justine Alexandra Roberts Tunney                              â
â                                                                              â
â Permission to use, copy, modify, and/or distribute this software for         â
â any purpose with or without fee is hereby granted, provided that the         â
â above copyright notice and this permission notice appear in all copies.      â
â                                                                              â
â THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                â
â WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                â
â WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             â
â AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         â
â DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        â
â PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               â
â TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             â
â PERFORMANCE OF THIS SOFTWARE.                                                â
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ*/
#include "libc/calls/calls.h"
#include "libc/calls/syscall-nt.internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/intrin/asan.internal.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/sysv/errfuns.h"
#include "libc/zipos/zipos.internal.h"

/**
 * Changes permissions on file, e.g.:
 *
 *     CHECK_NE(-1, fchmodat(AT_FDCWD, "foo/bar.txt", 0644));
 *     CHECK_NE(-1, fchmodat(AT_FDCWD, "o/default/program.com", 0755));
 *     CHECK_NE(-1, fchmodat(AT_FDCWD, "privatefolder/", 0700));
 *
 * @param path must exist
 * @param mode contains octal flags (base 8)
 * @param flags can have `AT_SYMLINK_NOFOLLOW`
 * @raise ENOTSUP if `dirfd` or `path` use zip file system
 * @errors ENOENT, ENOTDIR, ENOSYS
 * @asyncsignalsafe
 * @see fchmod()
 */
int fchmodat(int dirfd, const char *path, uint32_t mode, int flags) {
  int rc;
  if (IsAsan() && !__asan_is_valid_str(path)) {
    rc = efault();
  } else if (_weaken(__zipos_notat) &&
             (rc = __zipos_notat(dirfd, path)) == -1) {
    rc = enotsup();
  } else if (!IsWindows()) {
    rc = sys_fchmodat(dirfd, path, mode, flags);
  } else {
    rc = sys_fchmodat_nt(dirfd, path, mode, flags);
  }
  STRACE("fchmodat(%s, %#s, %#o, %d) â %d% m", DescribeDirfd(dirfd), path, mode,
         flags, rc);
  return rc;
}
