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03a8357e84
This is dirty but pretty cool! If we have a pending, unmasked signal for a process that's blocked inside the kernel, we set up alternate stacks for that process and unblock it to execute the signal handler. A slightly different return trampoline is used here: since we need to get back into the kernel, a dedicated syscall is used (sys$sigreturn.) This restores the TSS contents of the process to the state it was in while we were originally blocking in the kernel. NOTE: There's currently only one "kernel resume TSS" so signal nesting definitely won't work.
34 lines
602 B
C++
34 lines
602 B
C++
#include "FullDevice.h"
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#include "Limits.h"
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#include <LibC/errno_numbers.h>
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#include <AK/StdLib.h>
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#include <AK/kstdio.h>
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FullDevice::FullDevice()
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: CharacterDevice(1, 7)
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{
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}
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FullDevice::~FullDevice()
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{
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}
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bool FullDevice::hasDataAvailableForRead() const
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{
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return true;
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}
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Unix::ssize_t FullDevice::read(byte* buffer, Unix::size_t bufferSize)
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{
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Unix::size_t count = min(GoodBufferSize, bufferSize);
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memset(buffer, 0, count);
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return count;
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}
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Unix::ssize_t FullDevice::write(const byte*, Unix::size_t bufferSize)
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{
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if (bufferSize == 0)
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return 0;
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return -ENOSPC;
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}
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