/*
* 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/Assertions.h>
#include <AK/MemMem.h>
#include <AK/String.h>
#include <AK/Types.h>
#include <Kernel/Arch/i386/CPU.h>
#include <Kernel/Heap/kmalloc.h>
#include <Kernel/StdLib.h>
#include <Kernel/VM/MemoryManager.h>
String copy_string_from_user(const char* user_str, size_t user_str_size)
{
bool is_user = Kernel::is_user_range(VirtualAddress(user_str), user_str_size);
ASSERT(is_user); // For now assert to catch bugs, but technically not an error
if (!is_user)
return {};
Kernel::SmapDisabler disabler;
void* fault_at;
ssize_t length = Kernel::safe_strnlen(user_str, user_str_size, fault_at);
if (length < 0) {
klog() << "copy_string_from_user(" << user_str << ", " << user_str_size << ") failed at " << VirtualAddress(fault_at) << " (strnlen)";
return {};
}
if (length == 0)
return String::empty();
char* buffer;
auto copied_string = StringImpl::create_uninitialized((size_t)length, buffer);
if (!Kernel::safe_memcpy(buffer, user_str, (size_t)length, fault_at)) {
klog() << "copy_string_from_user(" << user_str << ", " << user_str_size << ") failed at " << VirtualAddress(fault_at) << " (memcpy)";
return {};
}
return copied_string;
}
String copy_string_from_user(Userspace<const char*> user_str, size_t user_str_size)
{
return copy_string_from_user(user_str.unsafe_userspace_ptr(), user_str_size);
}
extern "C" {
bool copy_to_user(void* dest_ptr, const void* src_ptr, size_t n)
{
bool is_user = Kernel::is_user_range(VirtualAddress(dest_ptr), n);
ASSERT(is_user); // For now assert to catch bugs, but technically not an error
if (!is_user)
return false;
ASSERT(!Kernel::is_user_range(VirtualAddress(src_ptr), n));
Kernel::SmapDisabler disabler;
void* fault_at;
if (!Kernel::safe_memcpy(dest_ptr, src_ptr, n, fault_at)) {
ASSERT(VirtualAddress(fault_at) >= VirtualAddress(dest_ptr) && VirtualAddress(fault_at) <= VirtualAddress((FlatPtr)dest_ptr + n));
klog() << "copy_to_user(" << dest_ptr << ", " << src_ptr << ", " << n << ") failed at " << VirtualAddress(fault_at);
return false;
}
return true;
}
bool copy_from_user(void* dest_ptr, const void* src_ptr, size_t n)
{
bool is_user = Kernel::is_user_range(VirtualAddress(src_ptr), n);
ASSERT(is_user); // For now assert to catch bugs, but technically not an error
if (!is_user)
return false;
ASSERT(!Kernel::is_user_range(VirtualAddress(dest_ptr), n));
Kernel::SmapDisabler disabler;
void* fault_at;
if (!Kernel::safe_memcpy(dest_ptr, src_ptr, n, fault_at)) {
ASSERT(VirtualAddress(fault_at) >= VirtualAddress(src_ptr) && VirtualAddress(fault_at) <= VirtualAddress((FlatPtr)src_ptr + n));
klog() << "copy_from_user(" << dest_ptr << ", " << src_ptr << ", " << n << ") failed at " << VirtualAddress(fault_at);
return false;
}
return true;
}
void* memcpy(void* dest_ptr, const void* src_ptr, size_t n)
{
size_t dest = (size_t)dest_ptr;
size_t src = (size_t)src_ptr;
// FIXME: Support starting at an unaligned address.
if (!(dest & 0x3) && !(src & 0x3) && n >= 12) {
size_t size_ts = n / sizeof(size_t);
asm volatile(
"rep movsl\n"
: "=S"(src), "=D"(dest)
: "S"(src), "D"(dest), "c"(size_ts)
: "memory");
n -= size_ts * sizeof(size_t);
if (n == 0)
return dest_ptr;
}
asm volatile(
"rep movsb\n" ::"S"(src), "D"(dest), "c"(n)
: "memory");
return dest_ptr;
}
void* memmove(void* dest, const void* src, size_t n)
{
if (dest < src)
return memcpy(dest, src, n);
u8* pd = (u8*)dest;
const u8* ps = (const u8*)src;
for (pd += n, ps += n; n--;)
*--pd = *--ps;
return dest;
}
const void* memmem(const void* haystack, size_t haystack_length, const void* needle, size_t needle_length)
{
return AK::memmem(haystack, haystack_length, needle, needle_length);
}
[[nodiscard]] bool memset_user(void* dest_ptr, int c, size_t n)
{
bool is_user = Kernel::is_user_range(VirtualAddress(dest_ptr), n);
ASSERT(is_user); // For now assert to catch bugs, but technically not an error
if (!is_user)
return false;
Kernel::SmapDisabler disabler;
void* fault_at;
if (!Kernel::safe_memset(dest_ptr, c, n, fault_at)) {
klog() << "memset(" << dest_ptr << ", " << n << ") failed at " << VirtualAddress(fault_at);
return false;
}
return true;
}
void* memset(void* dest_ptr, int c, size_t n)
{
size_t dest = (size_t)dest_ptr;
// FIXME: Support starting at an unaligned address.
if (!(dest & 0x3) && n >= 12) {
size_t size_ts = n / sizeof(size_t);
size_t expanded_c = (u8)c;
expanded_c |= expanded_c << 8;
expanded_c |= expanded_c << 16;
asm volatile(
"rep stosl\n"
: "=D"(dest)
: "D"(dest), "c"(size_ts), "a"(expanded_c)
: "memory");
n -= size_ts * sizeof(size_t);
if (n == 0)
return dest_ptr;
}
asm volatile(
"rep stosb\n"
: "=D"(dest), "=c"(n)
: "0"(dest), "1"(n), "a"(c)
: "memory");
return dest_ptr;
}
size_t strlen(const char* str)
{
size_t len = 0;
while (*(str++))
++len;
return len;
}
size_t strnlen(const char* str, size_t maxlen)
{
size_t len = 0;
for (; len < maxlen && *str; str++)
len++;
return len;
}
int strcmp(const char* s1, const char* s2)
{
for (; *s1 == *s2; ++s1, ++s2) {
if (*s1 == 0)
return 0;
}
return *(const u8*)s1 < *(const u8*)s2 ? -1 : 1;
}
int memcmp(const void* v1, const void* v2, size_t n)
{
auto* s1 = (const u8*)v1;
auto* s2 = (const u8*)v2;
while (n-- > 0) {
if (*s1++ != *s2++)
return s1[-1] < s2[-1] ? -1 : 1;
}
return 0;
}
int strncmp(const char* s1, const char* s2, size_t n)
{
if (!n)
return 0;
do {
if (*s1 != *s2++)
return *(const unsigned char*)s1 - *(const unsigned char*)--s2;
if (*s1++ == 0)
break;
} while (--n);
return 0;
}
char* strstr(const char* haystack, const char* needle)
{
char nch;
char hch;
if ((nch = *needle++) != 0) {
size_t len = strlen(needle);
do {
do {
if ((hch = *haystack++) == 0)
return nullptr;
} while (hch != nch);
} while (strncmp(haystack, needle, len) != 0);
--haystack;
}
return const_cast<char*>(haystack);
}
void* realloc(void* p, size_t s)
{
return krealloc(p, s);
}
void free(void* p)
{
return kfree(p);
}
// Functions that are automatically called by the C++ compiler.
// Declare them first, to tell the silly compiler that they are indeed being used.
[[noreturn]] void __stack_chk_fail();
[[noreturn]] void __stack_chk_fail_local();
extern "C" int __cxa_atexit(void (*)(void*), void*, void*);
[[noreturn]] void __cxa_pure_virtual();
[[noreturn]] void __stack_chk_fail()
{
ASSERT_NOT_REACHED();
}
[[noreturn]] void __stack_chk_fail_local()
{
ASSERT_NOT_REACHED();
}
extern "C" int __cxa_atexit(void (*)(void*), void*, void*)
{
ASSERT_NOT_REACHED();
return 0;
}
[[noreturn]] void __cxa_pure_virtual()
{
ASSERT_NOT_REACHED();
}
}