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Kernel: Reimplement the dbgputch and dbgputstr syscalls

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This rewrites the dbgputch and dbgputstr system calls as wrappers of
kstdio.h.

This fixes a bug where only the Kernel's debug output was also sent to
a serial debugger, while the userspace's debug output was only sent to
the Bochs debugger.

This also fixes a bug where debug output from one process would
sometimes "interrupt" the debug output from another process in the
middle of a line.
This commit is contained in:
Max Wipfli 2021-06-23 17:55:08 +02:00 • committed by Andreas Kling
parent 67067904f5
commit 84c0f98fb2
1 changed files with 8 additions and 14 deletions
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22
Kernel/Syscalls/debug.cpp
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@ -4,10 +4,10 @@
* SPDX-License-Identifier: BSD-2-Clause * SPDX-License-Identifier: BSD-2-Clause
*/ */
#include <Kernel/IO.h>
#include <Kernel/KSyms.h> #include <Kernel/KSyms.h>
#include <Kernel/Process.h> #include <Kernel/Process.h>
#include <Kernel/UserOrKernelBuffer.h> #include <Kernel/UserOrKernelBuffer.h>
#include <Kernel/kstdio.h>
namespace Kernel { namespace Kernel {
@ -19,26 +19,20 @@ KResultOr<int> Process::sys$dump_backtrace()
KResultOr<int> Process::sys$dbgputch(u8 ch) KResultOr<int> Process::sys$dbgputch(u8 ch)
{ {
IO::out8(IO::BOCHS_DEBUG_PORT, ch); dbgputch(ch);
return 0; return 0;
} }
KResultOr<size_t> Process::sys$dbgputstr(Userspace<const u8*> characters, size_t size) KResultOr<size_t> Process::sys$dbgputstr(Userspace<const u8*> characters, size_t size)
{ {
if (size <= 0) if (size == 0)
return 0; return 0;
if (size > NumericLimits<ssize_t>::max()) auto result = try_copy_kstring_from_user(reinterpret_cast<char const*>(characters.unsafe_userspace_ptr()), size);
return EINVAL; if (result.is_error())
return result.error();
auto buffer = UserOrKernelBuffer::for_user_buffer(characters, size); dbgputstr(reinterpret_cast<const char*>(result.value()->characters()), size);
if (!buffer.has_value()) return size;
return EFAULT;
return buffer.value().read_buffered<1024>(size, [&](u8 const* buffer, size_t buffer_size) {
for (size_t i = 0; i < buffer_size; ++i)
IO::out8(IO::BOCHS_DEBUG_PORT, buffer[i]);
return buffer_size;
});
} }
} }