platform_bionic/libc/bionic/open.cpp

/*
 * Copyright (C) 2008 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <fcntl.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>

#include "private/bionic_fortify.h"

extern "C" int __openat(int, const char*, int, int);

static inline int force_O_LARGEFILE(int flags) {
#if defined(__LP64__)
  return flags; // No need, and aarch64's strace gets confused.
#else
  return flags | O_LARGEFILE;
#endif
}

static inline bool needs_mode(int flags) {
  return ((flags & O_CREAT) == O_CREAT) || ((flags & O_TMPFILE) == O_TMPFILE);
}

int creat(const char* pathname, mode_t mode) {
  return open(pathname, O_CREAT | O_TRUNC | O_WRONLY, mode);
}
__strong_alias(creat64, creat);

int open(const char* pathname, int flags, ...) {
  mode_t mode = 0;

  if (needs_mode(flags)) {
    va_list args;
    va_start(args, flags);
    mode = static_cast<mode_t>(va_arg(args, int));
    va_end(args);
  }

  return __openat(AT_FDCWD, pathname, force_O_LARGEFILE(flags), mode);
}
__strong_alias(open64, open);

int __open_2(const char* pathname, int flags) {
  if (needs_mode(flags)) __fortify_fatal("open: called with O_CREAT/O_TMPFILE but no mode");
  return __openat(AT_FDCWD, pathname, force_O_LARGEFILE(flags), 0);
}

int openat(int fd, const char *pathname, int flags, ...) {
  mode_t mode = 0;

  if (needs_mode(flags)) {
    va_list args;
    va_start(args, flags);
    mode = static_cast<mode_t>(va_arg(args, int));
    va_end(args);
  }

  return __openat(fd, pathname, force_O_LARGEFILE(flags), mode);
}
__strong_alias(openat64, openat);

int __openat_2(int fd, const char* pathname, int flags) {
  if (needs_mode(flags)) __fortify_fatal("open: called with O_CREAT/O_TMPFILE but no mode");
  return __openat(fd, pathname, force_O_LARGEFILE(flags), 0);
}