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ladybird/Kernel/Syscalls/futex.cpp

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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 21:38:15 +00:00
/*
* 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/Time.h>
#include <Kernel/Process.h>
namespace Kernel {
Kernel: Mark compilation-unit-only functions as static This enables a nice warning in case a function becomes dead code. Also, in case of signal_trampoline_dummy, marking it external (non-static) prevents it from being 'optimized away', which would lead to surprising and weird linker errors. I found these places by using -Wmissing-declarations. The Kernel still shows these issues, which I think are false-positives, but don't want to touch: - Kernel/Arch/i386/CPU.cpp:1081:17: void Kernel::enter_thread_context(Kernel::Thread*, Kernel::Thread*) - Kernel/Arch/i386/CPU.cpp:1170:17: void Kernel::context_first_init(Kernel::Thread*, Kernel::Thread*, Kernel::TrapFrame*) - Kernel/Arch/i386/CPU.cpp:1304:16: u32 Kernel::do_init_context(Kernel::Thread*, u32) - Kernel/Arch/i386/CPU.cpp:1347:17: void Kernel::pre_init_finished() - Kernel/Arch/i386/CPU.cpp:1360:17: void Kernel::post_init_finished() No idea, not gonna touch it. - Kernel/init.cpp:104:30: void Kernel::init() - Kernel/init.cpp:167:30: void Kernel::init_ap(u32, Kernel::Processor*) - Kernel/init.cpp:184:17: void Kernel::init_finished(u32) Called by boot.S. - Kernel/init.cpp:383:16: int Kernel::__cxa_atexit(void (*)(void*), void*, void*) - Kernel/StdLib.cpp:285:19: void __cxa_pure_virtual() - Kernel/StdLib.cpp:300:19: void __stack_chk_fail() - Kernel/StdLib.cpp:305:19: void __stack_chk_fail_local() Not sure how to tell the compiler that the compiler is already using them. Also, maybe __cxa_atexit should go into StdLib.cpp? - Kernel/Modules/TestModule.cpp:31:17: void module_init() - Kernel/Modules/TestModule.cpp:40:17: void module_fini() Could maybe go into a new header. This would also provide type-checking for new modules.
2020-08-10 19:12:13 +00:00
static void compute_relative_timeout_from_absolute(const timeval& absolute_time, timeval& relative_time)
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 21:38:15 +00:00
{
// Convert absolute time to relative time of day.
timeval_sub(absolute_time, kgettimeofday(), relative_time);
}
Kernel: Mark compilation-unit-only functions as static This enables a nice warning in case a function becomes dead code. Also, in case of signal_trampoline_dummy, marking it external (non-static) prevents it from being 'optimized away', which would lead to surprising and weird linker errors. I found these places by using -Wmissing-declarations. The Kernel still shows these issues, which I think are false-positives, but don't want to touch: - Kernel/Arch/i386/CPU.cpp:1081:17: void Kernel::enter_thread_context(Kernel::Thread*, Kernel::Thread*) - Kernel/Arch/i386/CPU.cpp:1170:17: void Kernel::context_first_init(Kernel::Thread*, Kernel::Thread*, Kernel::TrapFrame*) - Kernel/Arch/i386/CPU.cpp:1304:16: u32 Kernel::do_init_context(Kernel::Thread*, u32) - Kernel/Arch/i386/CPU.cpp:1347:17: void Kernel::pre_init_finished() - Kernel/Arch/i386/CPU.cpp:1360:17: void Kernel::post_init_finished() No idea, not gonna touch it. - Kernel/init.cpp:104:30: void Kernel::init() - Kernel/init.cpp:167:30: void Kernel::init_ap(u32, Kernel::Processor*) - Kernel/init.cpp:184:17: void Kernel::init_finished(u32) Called by boot.S. - Kernel/init.cpp:383:16: int Kernel::__cxa_atexit(void (*)(void*), void*, void*) - Kernel/StdLib.cpp:285:19: void __cxa_pure_virtual() - Kernel/StdLib.cpp:300:19: void __stack_chk_fail() - Kernel/StdLib.cpp:305:19: void __stack_chk_fail_local() Not sure how to tell the compiler that the compiler is already using them. Also, maybe __cxa_atexit should go into StdLib.cpp? - Kernel/Modules/TestModule.cpp:31:17: void module_init() - Kernel/Modules/TestModule.cpp:40:17: void module_fini() Could maybe go into a new header. This would also provide type-checking for new modules.
2020-08-10 19:12:13 +00:00
static void compute_relative_timeout_from_absolute(const timespec& absolute_time, timeval& relative_time)
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
{
timeval tv_absolute_time;
timespec_to_timeval(absolute_time, tv_absolute_time);
compute_relative_timeout_from_absolute(tv_absolute_time, relative_time);
}
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
WaitQueue& Process::futex_queue(Userspace<const i32*> userspace_address)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 21:38:15 +00:00
{
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
auto& queue = m_futex_queues.ensure(userspace_address.ptr());
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
if (!queue)
queue = make<WaitQueue>();
return *queue;
}
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
int Process::sys$futex(Userspace<const Syscall::SC_futex_params*> user_params)
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
{
REQUIRE_PROMISE(thread);
Syscall::SC_futex_params params;
Kernel: Make copy_to/from_user safe and remove unnecessary checks Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
2020-09-12 03:11:07 +00:00
if (!copy_from_user(&params, user_params))
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 21:38:15 +00:00
return -EFAULT;
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
switch (params.futex_op) {
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 21:38:15 +00:00
case FUTEX_WAIT: {
i32 user_value;
Kernel: Make copy_to/from_user safe and remove unnecessary checks Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
2020-09-12 03:11:07 +00:00
if (!copy_from_user(&user_value, params.userspace_address))
return -EFAULT;
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
if (user_value != params.val)
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 21:38:15 +00:00
return -EAGAIN;
timespec ts_abstimeout { 0, 0 };
Kernel: Make copy_to/from_user safe and remove unnecessary checks Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
2020-09-12 03:11:07 +00:00
if (params.timeout && !copy_from_user(&ts_abstimeout, params.timeout))
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
return -EFAULT;
timeval* optional_timeout = nullptr;
timeval relative_timeout { 0, 0 };
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
if (params.timeout) {
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 21:38:15 +00:00
compute_relative_timeout_from_absolute(ts_abstimeout, relative_timeout);
optional_timeout = &relative_timeout;
}
// FIXME: This is supposed to be interruptible by a signal, but right now WaitQueue cannot be interrupted.
Kernel: Make copy_to/from_user safe and remove unnecessary checks Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
2020-09-12 03:11:07 +00:00
WaitQueue& wait_queue = futex_queue((FlatPtr)params.userspace_address);
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
Thread::BlockResult result = Thread::current()->wait_on(wait_queue, "Futex", optional_timeout);
if (result == Thread::BlockResult::InterruptedByTimeout) {
return -ETIMEDOUT;
}
break;
}
case FUTEX_WAKE:
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
if (params.val == 0)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 21:38:15 +00:00
return 0;
Kernel: Use Userspace<T> for the futex syscall Utilizie Userspace<T> for the syscall argument itself, as well as internally in the SC_futex_params struct. We were double validating the SC_futex_params.timeout validation, that was removed as well.
2020-08-05 06:53:23 +00:00
if (params.val == 1) {
Kernel: Make copy_to/from_user safe and remove unnecessary checks Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
2020-09-12 03:11:07 +00:00
futex_queue((FlatPtr)params.userspace_address).wake_one();
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
} else {
Kernel: Make copy_to/from_user safe and remove unnecessary checks Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
2020-09-12 03:11:07 +00:00
futex_queue((FlatPtr)params.userspace_address).wake_n(params.val);
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 21:38:15 +00:00
}
break;
}
return 0;
}
}
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