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serenity/Kernel/Syscalls/read.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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 23:38:15 +02:00
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
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* SPDX-License-Identifier: BSD-2-Clause
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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. :^)
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*/
Meta: Split debug defines into multiple headers. The following script was used to make these changes: #!/bin/bash set -e tmp=$(mktemp -d) echo "tmp=$tmp" find Kernel \( -name '*.cpp' -o -name '*.h' \) | sort > $tmp/Kernel.files find . \( -path ./Toolchain -prune -o -path ./Build -prune -o -path ./Kernel -prune \) -o \( -name '*.cpp' -o -name '*.h' \) -print | sort > $tmp/EverythingExceptKernel.files cat $tmp/Kernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/Kernel.macros cat $tmp/EverythingExceptKernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/EverythingExceptKernel.macros comm -23 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/Kernel.unique comm -1 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/EverythingExceptKernel.unique cat $tmp/Kernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/Kernel.header cat $tmp/EverythingExceptKernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/EverythingExceptKernel.header for macro in $(cat $tmp/Kernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.new-includes ||: done cat $tmp/Kernel.new-includes | sort > $tmp/Kernel.new-includes.sorted for macro in $(cat $tmp/EverythingExceptKernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.old-includes ||: done cat $tmp/Kernel.old-includes | sort > $tmp/Kernel.old-includes.sorted comm -23 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.new comm -13 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.old comm -12 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.mixed for file in $(cat $tmp/Kernel.includes.new) do sed -i -E 's/#include <AK\/Debug\.h>/#include <Kernel\/Debug\.h>/' $file done for file in $(cat $tmp/Kernel.includes.mixed) do echo "mixed include in $file, requires manual editing." done
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#include <Kernel/Debug.h>
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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. :^)
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#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
namespace Kernel {
Kernel: Add bitwise operators for Thread::FileBlocker::BlockFlags enum Switch to using type-safe bitwise operators for the BlockFlags class, this cleans up a lot of boilerplate casts which are necessary when the enum is declared as `enum class`.
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using BlockFlags = Thread::FileBlocker::BlockFlags;
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 20:59:35 +02:00
KResultOr<FlatPtr> Process::sys$readv(int fd, Userspace<const struct iovec*> iov, int iov_count)
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
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{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
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REQUIRE_PROMISE(stdio);
if (iov_count < 0)
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
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return EINVAL;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
Kernel: Refuse excessively long iovec list, also in readv This bug is a good example why copy-paste code should eventually be eliminated from the code base: Apparently the code was copied from read.cpp before c6027ed7cce901dc0d2b6f68002a911178ae587f, so the same bug got introduced here. To recap: A malicious program can ask the Kernel to prepare sys-ing to a huge amount of iovecs. The Kernel must first copy all the vector locations into 'vecs', and before that allocates an arbitrary amount of memory: vecs.resize(iov_count); This can cause Kernel memory exhaustion, triggered by any malicious userland program.
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// Arbitrary pain threshold.
if (iov_count > (int)MiB)
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
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return EFAULT;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
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u64 total_length = 0;
Vector<iovec, 32> vecs;
Kernel: Harden sys$readv / sys$writev Vector usage against OOM.
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if (!vecs.try_resize(iov_count))
return ENOMEM;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
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if (!copy_n_from_user(vecs.data(), iov, iov_count))
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
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return EFAULT;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
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for (auto& vec : vecs) {
total_length += vec.iov_len;
if (total_length > NumericLimits<i32>::max())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
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return EINVAL;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
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}
Kernel: Don't copy a Vector<FileDescriptionAndFlags> Instead of copying a Vector everytime we need to enumerate a Process' file descriptions, we can just temporarily lock so it won't change.
2021-06-22 21:22:17 +03:00
auto description = fds().file_description(fd);
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
if (!description)
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
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return EBADF;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
if (!description->is_readable())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
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return EBADF;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
if (description->is_directory())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
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return EISDIR;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
int nread = 0;
for (auto& vec : vecs) {
if (description->is_blocking()) {
if (!description->can_read()) {
Kernel: Add bitwise operators for Thread::FileBlocker::BlockFlags enum Switch to using type-safe bitwise operators for the BlockFlags class, this cleans up a lot of boilerplate casts which are necessary when the enum is declared as `enum class`.
2021-03-07 03:01:11 -08:00
auto unblock_flags = BlockFlags::None;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EINTR;
Kernel: Add bitwise operators for Thread::FileBlocker::BlockFlags enum Switch to using type-safe bitwise operators for the BlockFlags class, this cleans up a lot of boilerplate casts which are necessary when the enum is declared as `enum class`.
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if (!has_flag(unblock_flags, BlockFlags::Read))
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EAGAIN;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
// TODO: handle exceptions in unblock_flags
}
}
auto buffer = UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len);
if (!buffer.has_value())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EFAULT;
Kernel+LibC: Implement readv We already had writev, so let's just add readv too.
2021-02-12 05:40:03 +03:30
auto result = description->read(buffer.value(), vec.iov_len);
if (result.is_error())
return result.error();
nread += result.value();
}
return nread;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 20:59:35 +02:00
KResultOr<FlatPtr> Process::sys$read(int fd, Userspace<u8*> buffer, size_t size)
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 23:38:15 +02:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 11:20:12 -07:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 23:38:15 +02:00
REQUIRE_PROMISE(stdio);
if (size == 0)
return 0;
Kernel: Remove various other uses of ssize_t
2021-06-16 16:44:15 +02:00
if (size > NumericLimits<ssize_t>::max())
return EINVAL;
Everywhere: Replace dbgln<flag>(...) with dbgln_if(flag, ...) Replacement made by `find Kernel Userland -name '*.h' -o -name '*.cpp' | sed -i -Ee 's/dbgln\b<(\w+)>\(/dbgln_if(\1, /g'`
2021-02-07 15:33:24 +03:30
dbgln_if(IO_DEBUG, "sys$read({}, {}, {})", fd, buffer.ptr(), size);
Kernel: Don't copy a Vector<FileDescriptionAndFlags> Instead of copying a Vector everytime we need to enumerate a Process' file descriptions, we can just temporarily lock so it won't change.
2021-06-22 21:22:17 +03:00
auto description = fds().file_description(fd);
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 23:38:15 +02:00
if (!description)
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EBADF;
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 23:38:15 +02:00
if (!description->is_readable())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EBADF;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 23:38:15 +02:00
if (description->is_directory())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EISDIR;
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 23:38:15 +02:00
if (description->is_blocking()) {
if (!description->can_read()) {
Kernel: Add bitwise operators for Thread::FileBlocker::BlockFlags enum Switch to using type-safe bitwise operators for the BlockFlags class, this cleans up a lot of boilerplate casts which are necessary when the enum is declared as `enum class`.
2021-03-07 03:01:11 -08:00
auto unblock_flags = BlockFlags::None;
AK: Simplify constructors and conversions from nullptr_t Problem: - Many constructors are defined as `{}` rather than using the ` = default` compiler-provided constructor. - Some types provide an implicit conversion operator from `nullptr_t` instead of requiring the caller to default construct. This violates the C++ Core Guidelines suggestion to declare single-argument constructors explicit (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit). Solution: - Change default constructors to use the compiler-provided default constructor. - Remove implicit conversion operators from `nullptr_t` and change usage to enforce type consistency without conversion.
2021-01-10 16:29:28 -07:00
if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EINTR;
Kernel: Add bitwise operators for Thread::FileBlocker::BlockFlags enum Switch to using type-safe bitwise operators for the BlockFlags class, this cleans up a lot of boilerplate casts which are necessary when the enum is declared as `enum class`.
2021-03-07 03:01:11 -08:00
if (!has_flag(unblock_flags, BlockFlags::Read))
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EAGAIN;
Kernel: Move block condition evaluation out of the Scheduler This makes the Scheduler a lot leaner by not having to evaluate block conditions every time it is invoked. Instead evaluate them as the states change, and unblock threads at that point. This also implements some more waitid/waitpid/wait features and behavior. For example, WUNTRACED and WNOWAIT are now supported. And wait will now not return EINTR when SIGCHLD is delivered at the same time.
2020-11-29 16:05:27 -07:00
// TODO: handle exceptions in unblock_flags
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 23:38:15 +02:00
}
}
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.
2020-09-11 21:11:07 -06:00
auto user_buffer = UserOrKernelBuffer::for_user_buffer(buffer, size);
if (!user_buffer.has_value())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 13:49:16 +01:00
return EFAULT;
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.
2020-09-11 21:11:07 -06:00
auto result = description->read(user_buffer.value(), size);
Kernel: Make File::write() and File::read() return KResultOr<size_t> Instead of returning a ssize_t where negative values mean error, we now return KResultOr<size_t> and use the error state to report errors exclusively.
2020-08-04 18:02:23 +02:00
if (result.is_error())
return result.error();
return result.value();
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 23:38:15 +02:00
}
}
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