RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-15 07:04:59 +00:00
Code Issues Activity Actions

Kernel: Add a writev() syscall for writing multiple buffers in one go.

Browse source 
We then use this immediately in the WindowServer/LibGUI communication in
order to send both message + optional "extra data" with a single syscall.
This commit is contained in:
Andreas Kling 2019-05-10 03:19:25 +02:00
parent e6443649cb
commit 99aead4857
8 changed files with 111 additions and 54 deletions
Download patch file Download diff file Expand all files Collapse all files

105
Kernel/Process.cpp
View file

@ -818,6 +818,77 @@ int Process::sys$ptsname_r(int fd, char* buffer, ssize_t size)
return 0;
}
ssize_t Process::sys$writev(int fd, const struct iovec* iov, int iov_count)
{
if (iov_count < 0)
return -EINVAL;
if (!validate_read_typed(iov, iov_count))
return -EFAULT;
// FIXME: Return EINVAL if sum of iovecs is greater than INT_MAX
auto* descriptor = file_descriptor(fd);
if (!descriptor)
return -EBADF;
int nwritten = 0;
for (int i = 0; i < iov_count; ++i) {
int rc = do_write(*descriptor, (const byte*)iov[i].iov_base, iov[i].iov_len);
if (rc < 0) {
if (nwritten == 0)
return rc;
return nwritten;
}
nwritten += rc;
}
if (current->has_unmasked_pending_signals()) {
current->block(Thread::State::BlockedSignal);
if (nwritten == 0)
return -EINTR;
}
return nwritten;
}
ssize_t Process::do_write(FileDescriptor& descriptor, const byte* data, int data_size)
{
ssize_t nwritten = 0;
if (!descriptor.is_blocking())
return descriptor.write(data, data_size);
while (nwritten < data_size) {
#ifdef IO_DEBUG
dbgprintf("while %u < %u\n", nwritten, size);
#endif
if (!descriptor.can_write()) {
#ifdef IO_DEBUG
dbgprintf("block write on %d\n", fd);
#endif
current->block(Thread::State::BlockedWrite, descriptor);
}
ssize_t rc = descriptor.write(data + nwritten, data_size - nwritten);
#ifdef IO_DEBUG
dbgprintf(" -> write returned %d\n", rc);
#endif
if (rc < 0) {
// FIXME: Support returning partial nwritten with errno.
ASSERT(nwritten == 0);
return rc;
}
if (rc == 0)
break;
if (current->has_unmasked_pending_signals()) {
current->block(Thread::State::BlockedSignal);
if (nwritten == 0)
return -EINTR;
}
nwritten += rc;
}
return nwritten;
}
ssize_t Process::sys$write(int fd, const byte* data, ssize_t size)
{
if (size < 0)
@ -832,39 +903,7 @@ ssize_t Process::sys$write(int fd, const byte* data, ssize_t size)
auto* descriptor = file_descriptor(fd);
if (!descriptor)
return -EBADF;
ssize_t nwritten = 0;
if (descriptor->is_blocking()) {
while (nwritten < (ssize_t)size) {
#ifdef IO_DEBUG
dbgprintf("while %u < %u\n", nwritten, size);
#endif
if (!descriptor->can_write()) {
#ifdef IO_DEBUG
dbgprintf("block write on %d\n", fd);
#endif
current->block(Thread::State::BlockedWrite, *descriptor);
}
ssize_t rc = descriptor->write((const byte*)data + nwritten, size - nwritten);
#ifdef IO_DEBUG
dbgprintf(" -> write returned %d\n", rc);
#endif
if (rc < 0) {
// FIXME: Support returning partial nwritten with errno.
ASSERT(nwritten == 0);
return rc;
}
if (rc == 0)
break;
if (current->has_unmasked_pending_signals()) {
current->block(Thread::State::BlockedSignal);
if (nwritten == 0)
return -EINTR;
}
nwritten += rc;
}
} else {
nwritten = descriptor->write((const byte*)data, size);
}
auto nwritten = do_write(*descriptor, data, size);
if (current->has_unmasked_pending_signals()) {
current->block(Thread::State::BlockedSignal);
if (nwritten == 0)