serenity/Kernel/Syscalls/write.cpp
Andreas Kling 949aef4aef Kernel: Move syscall implementations out of Process.cpp
This is something I've been meaning to do for a long time, and here we
finally go. This patch moves all sys$foo functions out of Process.cpp
and into files in Kernel/Syscalls/.

It's not exactly one syscall per file (although it could be, but I got
a bit tired of the repetitive work here..)

This makes hacking on individual syscalls a lot less painful since you
don't have to rebuild nearly as much code every time. I'm also hopeful
that this makes it easier to understand individual syscalls. :^)
2020-07-30 23:40:57 +02:00

146 lines
4.4 KiB
C++

/*
* 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.
*/
#include <AK/NumericLimits.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
namespace Kernel {
ssize_t Process::sys$writev(int fd, const struct iovec* iov, int iov_count)
{
REQUIRE_PROMISE(stdio);
if (iov_count < 0)
return -EINVAL;
if (!validate_read_typed(iov, iov_count))
return -EFAULT;
u64 total_length = 0;
Vector<iovec, 32> vecs;
vecs.resize(iov_count);
copy_from_user(vecs.data(), iov, iov_count * sizeof(iovec));
for (auto& vec : vecs) {
if (!validate_read(vec.iov_base, vec.iov_len))
return -EFAULT;
total_length += vec.iov_len;
if (total_length > NumericLimits<i32>::max())
return -EINVAL;
}
auto description = file_description(fd);
if (!description)
return -EBADF;
if (!description->is_writable())
return -EBADF;
int nwritten = 0;
for (auto& vec : vecs) {
int rc = do_write(*description, (const u8*)vec.iov_base, vec.iov_len);
if (rc < 0) {
if (nwritten == 0)
return rc;
return nwritten;
}
nwritten += rc;
}
return nwritten;
}
ssize_t Process::do_write(FileDescription& description, const u8* data, int data_size)
{
ssize_t nwritten = 0;
if (!description.is_blocking()) {
if (!description.can_write())
return -EAGAIN;
}
if (description.should_append()) {
#ifdef IO_DEBUG
dbg() << "seeking to end (O_APPEND)";
#endif
description.seek(0, SEEK_END);
}
while (nwritten < data_size) {
#ifdef IO_DEBUG
dbg() << "while " << nwritten << " < " << size;
#endif
if (!description.can_write()) {
if (!description.is_blocking()) {
// Short write: We can no longer write to this non-blocking description.
ASSERT(nwritten > 0);
return nwritten;
}
#ifdef IO_DEBUG
dbg() << "block write on " << description.absolute_path();
#endif
if (Thread::current()->block<Thread::WriteBlocker>(description).was_interrupted()) {
if (nwritten == 0)
return -EINTR;
}
}
ssize_t rc = description.write(data + nwritten, data_size - nwritten);
#ifdef IO_DEBUG
dbg() << " -> write returned " << rc;
#endif
if (rc < 0) {
if (nwritten)
return nwritten;
return rc;
}
if (rc == 0)
break;
nwritten += rc;
}
return nwritten;
}
ssize_t Process::sys$write(int fd, const u8* data, ssize_t size)
{
REQUIRE_PROMISE(stdio);
if (size < 0)
return -EINVAL;
if (size == 0)
return 0;
if (!validate_read(data, size))
return -EFAULT;
#ifdef DEBUG_IO
dbg() << "sys$write(" << fd << ", " << (const void*)(data) << ", " << size << ")";
#endif
auto description = file_description(fd);
if (!description)
return -EBADF;
if (!description->is_writable())
return -EBADF;
return do_write(*description, data, size);
}
}