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- /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- * list of conditions and the following disclaimer.
- *
- * 2. 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 HOLDER 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.
- */
- #ifdef __serenity__
- # include <Kernel/API/Syscall.h>
- #endif
- #include <AK/ScopeGuard.h>
- #include <LibCore/File.h>
- #include <errno.h>
- #include <fcntl.h>
- #include <libgen.h>
- #include <stdio.h>
- #include <string.h>
- #include <sys/stat.h>
- #include <unistd.h>
- namespace Core {
- Result<NonnullRefPtr<File>, String> File::open(const String& filename, IODevice::OpenMode mode, mode_t permissions)
- {
- auto file = File::construct(filename);
- if (!file->open_impl(mode, permissions))
- return String(file->error_string());
- return file;
- }
- File::File(const StringView& filename, Object* parent)
- : IODevice(parent)
- , m_filename(filename)
- {
- }
- File::~File()
- {
- if (m_should_close_file_descriptor == ShouldCloseFileDescriptor::Yes && mode() != NotOpen)
- close();
- }
- bool File::open(int fd, IODevice::OpenMode mode, ShouldCloseFileDescriptor should_close)
- {
- set_fd(fd);
- set_mode(mode);
- m_should_close_file_descriptor = should_close;
- return true;
- }
- bool File::open(IODevice::OpenMode mode)
- {
- return open_impl(mode, 0666);
- }
- bool File::open_impl(IODevice::OpenMode mode, mode_t permissions)
- {
- ASSERT(!m_filename.is_null());
- int flags = 0;
- if ((mode & IODevice::ReadWrite) == IODevice::ReadWrite) {
- flags |= O_RDWR | O_CREAT;
- } else if (mode & IODevice::ReadOnly) {
- flags |= O_RDONLY;
- } else if (mode & IODevice::WriteOnly) {
- flags |= O_WRONLY | O_CREAT;
- bool should_truncate = !((mode & IODevice::Append) || (mode & IODevice::MustBeNew));
- if (should_truncate)
- flags |= O_TRUNC;
- }
- if (mode & IODevice::Append)
- flags |= O_APPEND;
- if (mode & IODevice::Truncate)
- flags |= O_TRUNC;
- if (mode & IODevice::MustBeNew)
- flags |= O_EXCL;
- int fd = ::open(m_filename.characters(), flags, permissions);
- if (fd < 0) {
- set_error(errno);
- return false;
- }
- set_fd(fd);
- set_mode(mode);
- return true;
- }
- bool File::is_directory() const
- {
- struct stat stat;
- if (fstat(fd(), &stat) < 0)
- return false;
- return S_ISDIR(stat.st_mode);
- }
- bool File::is_directory(const String& filename)
- {
- struct stat st;
- if (stat(filename.characters(), &st) < 0)
- return false;
- return S_ISDIR(st.st_mode);
- }
- bool File::exists(const String& filename)
- {
- struct stat st;
- return stat(filename.characters(), &st) == 0;
- }
- String File::real_path_for(const String& filename)
- {
- if (filename.is_null())
- return {};
- auto* path = realpath(filename.characters(), nullptr);
- String real_path(path);
- free(path);
- return real_path;
- }
- bool File::ensure_parent_directories(const String& path)
- {
- ASSERT(path.starts_with("/"));
- int saved_errno = 0;
- ScopeGuard restore_errno = [&saved_errno] { errno = saved_errno; };
- char* parent_buffer = strdup(path.characters());
- ScopeGuard free_buffer = [parent_buffer] { free(parent_buffer); };
- const char* parent = dirname(parent_buffer);
- int rc = mkdir(parent, 0755);
- saved_errno = errno;
- if (rc == 0 || errno == EEXIST)
- return true;
- if (errno != ENOENT)
- return false;
- bool ok = ensure_parent_directories(parent);
- saved_errno = errno;
- if (!ok)
- return false;
- rc = mkdir(parent, 0755);
- saved_errno = errno;
- return rc == 0;
- }
- #ifdef __serenity__
- String File::read_link(const StringView& link_path)
- {
- // First, try using a 64-byte buffer, that ought to be enough for anybody.
- char small_buffer[64];
- Syscall::SC_readlink_params small_params {
- { link_path.characters_without_null_termination(), link_path.length() },
- { small_buffer, sizeof(small_buffer) }
- };
- int rc = syscall(SC_readlink, &small_params);
- if (rc < 0) {
- errno = -rc;
- return {};
- }
- size_t size = rc;
- // If the call was successful, the syscall (unlike the LibC wrapper)
- // returns the full size of the link. Let's see if our small buffer
- // was enough to read the whole link.
- if (size <= sizeof(small_buffer))
- return { small_buffer, size };
- // Nope, but at least now we know the right size.
- char* large_buffer_ptr;
- auto large_buffer = StringImpl::create_uninitialized(size, large_buffer_ptr);
- Syscall::SC_readlink_params large_params {
- { link_path.characters_without_null_termination(), link_path.length() },
- { large_buffer_ptr, (size_t)size }
- };
- rc = syscall(SC_readlink, &large_params);
- if (rc < 0) {
- errno = -rc;
- return {};
- }
- size_t new_size = rc;
- if (new_size == size)
- return { *large_buffer };
- // If we're here, the symlink has changed while we were looking at it.
- // If it became shorter, our buffer is valid, we just have to trim it a bit.
- if (new_size < size)
- return { large_buffer_ptr, new_size };
- // Otherwise, here's not much we can do, unless we want to loop endlessly
- // in this case. Let's leave it up to the caller whether to loop.
- errno = -EAGAIN;
- return {};
- }
- #else
- // This is a sad version for other systems. It has to always make a copy of the
- // link path, and to always make two syscalls to get the right size first.
- String File::read_link(const StringView& link_path)
- {
- String link_path_str = link_path;
- struct stat statbuf;
- int rc = lstat(link_path_str.characters(), &statbuf);
- if (rc < 0)
- return {};
- char* buffer_ptr;
- auto buffer = StringImpl::create_uninitialized(statbuf.st_size, buffer_ptr);
- rc = readlink(link_path_str.characters(), buffer_ptr, statbuf.st_size);
- if (rc < 0)
- return {};
- // (See above.)
- if (rc == statbuf.st_size)
- return { *buffer };
- return { buffer_ptr, (size_t)rc };
- }
- #endif
- static RefPtr<File> stdin_file;
- static RefPtr<File> stdout_file;
- static RefPtr<File> stderr_file;
- NonnullRefPtr<File> File::standard_input()
- {
- if (!stdin_file) {
- stdin_file = File::construct();
- stdin_file->open(STDIN_FILENO, IODevice::ReadOnly, ShouldCloseFileDescriptor::No);
- }
- return *stdin_file;
- }
- NonnullRefPtr<File> File::standard_output()
- {
- if (!stdout_file) {
- stdout_file = File::construct();
- stdout_file->open(STDOUT_FILENO, IODevice::WriteOnly, ShouldCloseFileDescriptor::No);
- }
- return *stdout_file;
- }
- NonnullRefPtr<File> File::standard_error()
- {
- if (!stderr_file) {
- stderr_file = File::construct();
- stderr_file->open(STDERR_FILENO, IODevice::WriteOnly, ShouldCloseFileDescriptor::No);
- }
- return *stderr_file;
- }
- }
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