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ladybird/Kernel/Syscalls/link.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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 08:24:48 +00:00
* SPDX-License-Identifier: BSD-2-Clause
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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. :^)
2020-07-30 21:38:15 +00:00
*/
#include <AK/StringView.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Process.h>
namespace Kernel {
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 18:59:35 +00:00
KResultOr<FlatPtr> Process::sys$link(Userspace<const Syscall::SC_link_params*> user_params)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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
{
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 18:20:12 +00:00
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
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REQUIRE_PROMISE(cpath);
Syscall::SC_link_params params;
Kernel: Make copy_to/from_user safe and remove unnecessary checks Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
2020-09-12 03:11:07 +00:00
if (!copy_from_user(&params, user_params))
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 12:49:16 +00:00
return EFAULT;
Kernel: Use try_copy_kstring_from_user() in sys$link()
2021-08-05 21:13:39 +00:00
auto old_path_or_error = try_copy_kstring_from_user(params.old_path);
if (old_path_or_error.is_error())
return old_path_or_error.error();
auto new_path_or_error = try_copy_kstring_from_user(params.new_path);
if (new_path_or_error.is_error())
return new_path_or_error.error();
return VirtualFileSystem::the().link(old_path_or_error.value()->view(), new_path_or_error.value()->view(), current_directory());
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 18:59:35 +00:00
KResultOr<FlatPtr> Process::sys$symlink(Userspace<const Syscall::SC_symlink_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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 18:20:12 +00:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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 21:38:15 +00:00
REQUIRE_PROMISE(cpath);
Syscall::SC_symlink_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: 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 12:49:16 +00:00
return EFAULT;
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$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-30 21:38:15 +00:00
auto target = get_syscall_path_argument(params.target);
if (target.is_error())
return target.error();
auto linkpath = get_syscall_path_argument(params.linkpath);
if (linkpath.is_error())
return linkpath.error();
Kernel: Rename VFS => VirtualFileSystem
2021-07-10 22:25:24 +00:00
return VirtualFileSystem::the().symlink(target.value()->view(), linkpath.value()->view(), current_directory());
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$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
}
}
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