mirror of
https://github.com/LadybirdBrowser/ladybird.git
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494ead3eb8
These are needed by `libcxxabi`'s demangle support. `memchr` is taken straight-up from the `LibC/string.cpp` source code.
452 lines
13 KiB
C++
452 lines
13 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Assertions.h>
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#include <AK/MemMem.h>
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#include <AK/String.h>
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#include <AK/Types.h>
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#include <Kernel/Arch/x86/SmapDisabler.h>
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#include <Kernel/Heap/kmalloc.h>
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#include <Kernel/StdLib.h>
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#include <Kernel/VM/MemoryManager.h>
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String copy_string_from_user(const char* user_str, size_t user_str_size)
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{
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bool is_user = Kernel::is_user_range(VirtualAddress(user_str), user_str_size);
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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void* fault_at;
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ssize_t length = Kernel::safe_strnlen(user_str, user_str_size, fault_at);
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if (length < 0) {
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dbgln("copy_string_from_user({:p}, {}) failed at {} (strnlen)", static_cast<const void*>(user_str), user_str_size, VirtualAddress { fault_at });
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return {};
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}
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if (length == 0)
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return String::empty();
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char* buffer;
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auto copied_string = StringImpl::create_uninitialized((size_t)length, buffer);
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if (!Kernel::safe_memcpy(buffer, user_str, (size_t)length, fault_at)) {
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dbgln("copy_string_from_user({:p}, {}) failed at {} (memcpy)", static_cast<const void*>(user_str), user_str_size, VirtualAddress { fault_at });
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return {};
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}
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return copied_string;
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}
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String copy_string_from_user(Userspace<const char*> user_str, size_t user_str_size)
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{
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return copy_string_from_user(user_str.unsafe_userspace_ptr(), user_str_size);
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}
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Kernel::KResultOr<NonnullOwnPtr<Kernel::KString>> try_copy_kstring_from_user(const char* user_str, size_t user_str_size)
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{
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bool is_user = Kernel::is_user_range(VirtualAddress(user_str), user_str_size);
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if (!is_user)
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return EFAULT;
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Kernel::SmapDisabler disabler;
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void* fault_at;
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ssize_t length = Kernel::safe_strnlen(user_str, user_str_size, fault_at);
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if (length < 0) {
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dbgln("copy_kstring_from_user({:p}, {}) failed at {} (strnlen)", static_cast<const void*>(user_str), user_str_size, VirtualAddress { fault_at });
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return EFAULT;
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}
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char* buffer;
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auto new_string = Kernel::KString::try_create_uninitialized(length, buffer);
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if (!new_string)
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return ENOMEM;
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buffer[length] = '\0';
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if (length == 0)
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return new_string.release_nonnull();
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if (!Kernel::safe_memcpy(buffer, user_str, (size_t)length, fault_at)) {
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dbgln("copy_kstring_from_user({:p}, {}) failed at {} (memcpy)", static_cast<const void*>(user_str), user_str_size, VirtualAddress { fault_at });
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return EFAULT;
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}
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return new_string.release_nonnull();
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}
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Kernel::KResultOr<NonnullOwnPtr<Kernel::KString>> try_copy_kstring_from_user(Userspace<const char*> user_str, size_t user_str_size)
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{
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return try_copy_kstring_from_user(user_str.unsafe_userspace_ptr(), user_str_size);
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}
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[[nodiscard]] Optional<Time> copy_time_from_user(const timespec* ts_user)
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{
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timespec ts;
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if (!copy_from_user(&ts, ts_user, sizeof(timespec))) {
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return {};
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}
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return Time::from_timespec(ts);
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}
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[[nodiscard]] Optional<Time> copy_time_from_user(const timeval* tv_user)
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{
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timeval tv;
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if (!copy_from_user(&tv, tv_user, sizeof(timeval))) {
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return {};
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}
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return Time::from_timeval(tv);
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}
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template<>
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[[nodiscard]] Optional<Time> copy_time_from_user<const timeval>(Userspace<const timeval*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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template<>
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[[nodiscard]] Optional<Time> copy_time_from_user<timeval>(Userspace<timeval*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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template<>
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[[nodiscard]] Optional<Time> copy_time_from_user<const timespec>(Userspace<const timespec*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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template<>
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[[nodiscard]] Optional<Time> copy_time_from_user<timespec>(Userspace<timespec*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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Optional<u32> user_atomic_fetch_add_relaxed(volatile u32* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_add_relaxed(var, val);
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}
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Optional<u32> user_atomic_exchange_relaxed(volatile u32* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_exchange_relaxed(var, val);
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}
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Optional<u32> user_atomic_load_relaxed(volatile u32* var)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_load_relaxed(var);
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}
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bool user_atomic_store_relaxed(volatile u32* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return false; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return false;
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_store_relaxed(var, val);
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}
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Optional<bool> user_atomic_compare_exchange_relaxed(volatile u32* var, u32& expected, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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VERIFY(!Kernel::is_user_range(VirtualAddress(&expected), sizeof(expected)));
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_compare_exchange_relaxed(var, expected, val);
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}
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Optional<u32> user_atomic_fetch_and_relaxed(volatile u32* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_and_relaxed(var, val);
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}
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Optional<u32> user_atomic_fetch_and_not_relaxed(volatile u32* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_and_not_relaxed(var, val);
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}
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Optional<u32> user_atomic_fetch_or_relaxed(volatile u32* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_or_relaxed(var, val);
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}
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Optional<u32> user_atomic_fetch_xor_relaxed(volatile u32* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_xor_relaxed(var, val);
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}
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extern "C" {
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bool copy_to_user(void* dest_ptr, const void* src_ptr, size_t n)
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{
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bool is_user = Kernel::is_user_range(VirtualAddress(dest_ptr), n);
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if (!is_user)
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return false;
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VERIFY(!Kernel::is_user_range(VirtualAddress(src_ptr), n));
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Kernel::SmapDisabler disabler;
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void* fault_at;
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if (!Kernel::safe_memcpy(dest_ptr, src_ptr, n, fault_at)) {
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VERIFY(VirtualAddress(fault_at) >= VirtualAddress(dest_ptr) && VirtualAddress(fault_at) <= VirtualAddress((FlatPtr)dest_ptr + n));
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dbgln("copy_to_user({:p}, {:p}, {}) failed at {}", dest_ptr, src_ptr, n, VirtualAddress { fault_at });
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return false;
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}
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return true;
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}
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bool copy_from_user(void* dest_ptr, const void* src_ptr, size_t n)
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{
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bool is_user = Kernel::is_user_range(VirtualAddress(src_ptr), n);
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if (!is_user)
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return false;
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VERIFY(!Kernel::is_user_range(VirtualAddress(dest_ptr), n));
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Kernel::SmapDisabler disabler;
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void* fault_at;
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if (!Kernel::safe_memcpy(dest_ptr, src_ptr, n, fault_at)) {
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VERIFY(VirtualAddress(fault_at) >= VirtualAddress(src_ptr) && VirtualAddress(fault_at) <= VirtualAddress((FlatPtr)src_ptr + n));
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dbgln("copy_from_user({:p}, {:p}, {}) failed at {}", dest_ptr, src_ptr, n, VirtualAddress { fault_at });
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return false;
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}
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return true;
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}
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void* memcpy(void* dest_ptr, const void* src_ptr, size_t n)
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{
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size_t dest = (size_t)dest_ptr;
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size_t src = (size_t)src_ptr;
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// FIXME: Support starting at an unaligned address.
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if (!(dest & 0x3) && !(src & 0x3) && n >= 12) {
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size_t size_ts = n / sizeof(size_t);
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#if ARCH(I386)
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asm volatile(
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"rep movsl\n"
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: "=S"(src), "=D"(dest)
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: "S"(src), "D"(dest), "c"(size_ts)
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: "memory");
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#else
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asm volatile(
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"rep movsq\n"
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: "=S"(src), "=D"(dest)
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: "S"(src), "D"(dest), "c"(size_ts)
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: "memory");
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#endif
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n -= size_ts * sizeof(size_t);
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if (n == 0)
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return dest_ptr;
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}
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asm volatile(
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"rep movsb\n" ::"S"(src), "D"(dest), "c"(n)
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: "memory");
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return dest_ptr;
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}
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void* memmove(void* dest, const void* src, size_t n)
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{
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if (dest < src)
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return memcpy(dest, src, n);
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u8* pd = (u8*)dest;
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const u8* ps = (const u8*)src;
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for (pd += n, ps += n; n--;)
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*--pd = *--ps;
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return dest;
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}
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const void* memmem(const void* haystack, size_t haystack_length, const void* needle, size_t needle_length)
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{
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return AK::memmem(haystack, haystack_length, needle, needle_length);
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}
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[[nodiscard]] bool memset_user(void* dest_ptr, int c, size_t n)
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{
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bool is_user = Kernel::is_user_range(VirtualAddress(dest_ptr), n);
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if (!is_user)
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return false;
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Kernel::SmapDisabler disabler;
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void* fault_at;
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if (!Kernel::safe_memset(dest_ptr, c, n, fault_at)) {
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dbgln("memset_user({:p}, {}, {}) failed at {}", dest_ptr, c, n, VirtualAddress { fault_at });
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return false;
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}
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return true;
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}
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void* memset(void* dest_ptr, int c, size_t n)
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{
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size_t dest = (size_t)dest_ptr;
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// FIXME: Support starting at an unaligned address.
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if (!(dest & 0x3) && n >= 12) {
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size_t size_ts = n / sizeof(size_t);
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size_t expanded_c = explode_byte((u8)c);
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#if ARCH(I386)
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asm volatile(
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"rep stosl\n"
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: "=D"(dest)
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: "D"(dest), "c"(size_ts), "a"(expanded_c)
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: "memory");
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#else
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asm volatile(
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"rep stosq\n"
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: "=D"(dest)
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: "D"(dest), "c"(size_ts), "a"(expanded_c)
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: "memory");
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#endif
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n -= size_ts * sizeof(size_t);
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if (n == 0)
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return dest_ptr;
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}
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asm volatile(
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"rep stosb\n"
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: "=D"(dest), "=c"(n)
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: "0"(dest), "1"(n), "a"(c)
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: "memory");
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return dest_ptr;
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}
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size_t strlen(const char* str)
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{
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size_t len = 0;
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while (*(str++))
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++len;
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return len;
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}
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size_t strnlen(const char* str, size_t maxlen)
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{
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size_t len = 0;
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for (; len < maxlen && *str; str++)
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len++;
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return len;
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}
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int strcmp(const char* s1, const char* s2)
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{
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for (; *s1 == *s2; ++s1, ++s2) {
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if (*s1 == 0)
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return 0;
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}
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return *(const u8*)s1 < *(const u8*)s2 ? -1 : 1;
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}
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int memcmp(const void* v1, const void* v2, size_t n)
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{
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auto* s1 = (const u8*)v1;
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auto* s2 = (const u8*)v2;
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while (n-- > 0) {
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if (*s1++ != *s2++)
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return s1[-1] < s2[-1] ? -1 : 1;
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}
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return 0;
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}
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int strncmp(const char* s1, const char* s2, size_t n)
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{
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if (!n)
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return 0;
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do {
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if (*s1 != *s2++)
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return *(const unsigned char*)s1 - *(const unsigned char*)--s2;
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if (*s1++ == 0)
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break;
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} while (--n);
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return 0;
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}
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char* strstr(const char* haystack, const char* needle)
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{
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char nch;
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char hch;
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if ((nch = *needle++) != 0) {
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size_t len = strlen(needle);
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do {
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do {
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if ((hch = *haystack++) == 0)
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return nullptr;
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} while (hch != nch);
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} while (strncmp(haystack, needle, len) != 0);
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--haystack;
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}
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return const_cast<char*>(haystack);
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}
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void* memchr(const void* ptr, int c, size_t size)
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{
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char ch = c;
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auto* cptr = (const char*)ptr;
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for (size_t i = 0; i < size; ++i) {
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if (cptr[i] == ch)
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return const_cast<char*>(cptr + i);
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}
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return nullptr;
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}
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void* malloc(size_t s)
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{
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return kmalloc(s);
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}
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void* realloc(void* p, size_t s)
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{
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return krealloc(p, s);
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}
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void free(void* p)
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{
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return kfree(p);
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}
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// Functions that are automatically called by the C++ compiler.
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// Declare them first, to tell the silly compiler that they are indeed being used.
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[[noreturn]] void __stack_chk_fail() __attribute__((used));
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[[noreturn]] void __stack_chk_fail_local() __attribute__((used));
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extern "C" int __cxa_atexit(void (*)(void*), void*, void*);
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[[noreturn]] void __cxa_pure_virtual();
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[[noreturn]] void __stack_chk_fail()
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{
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VERIFY_NOT_REACHED();
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}
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[[noreturn]] void __stack_chk_fail_local()
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{
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VERIFY_NOT_REACHED();
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}
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extern "C" int __cxa_atexit(void (*)(void*), void*, void*)
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{
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VERIFY_NOT_REACHED();
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return 0;
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}
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[[noreturn]] void __cxa_pure_virtual()
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{
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VERIFY_NOT_REACHED();
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}
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}
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