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Kernel: Move syscall implementations out of Process.cpp

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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. :^)
This commit is contained in:
Andreas Kling 2020-07-30 23:38:15 +02:00
parent 027c450d6d
commit 949aef4aef
73 changed files with 6774 additions and 4485 deletions
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188
Kernel/Syscalls/module.cpp Normal file
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@ -0,0 +1,188 @@
/*
* 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 <Kernel/FileSystem/FileDescription.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/KSyms.h>
#include <Kernel/Module.h>
#include <Kernel/Process.h>
#include <LibELF/Loader.h>
namespace Kernel {
extern HashMap<String, OwnPtr<Module>>* g_modules;
int Process::sys$module_load(const char* user_path, size_t path_length)
{
if (!is_superuser())
return -EPERM;
REQUIRE_NO_PROMISES;
auto path = get_syscall_path_argument(user_path, path_length);
if (path.is_error())
return path.error();
auto description_or_error = VFS::the().open(path.value(), O_RDONLY, 0, current_directory());
if (description_or_error.is_error())
return description_or_error.error();
auto& description = description_or_error.value();
auto payload_or_error = description->read_entire_file();
if (payload_or_error.is_error())
return payload_or_error.error();
auto payload = payload_or_error.value();
auto storage = KBuffer::create_with_size(payload.size());
memcpy(storage.data(), payload.data(), payload.size());
payload.clear();
auto elf_image = make<ELF::Image>(storage.data(), storage.size());
if (!elf_image->parse())
return -ENOEXEC;
HashMap<String, u8*> section_storage_by_name;
auto module = make<Module>();
elf_image->for_each_section_of_type(SHT_PROGBITS, [&](const ELF::Image::Section& section) {
if (!section.size())
return IterationDecision::Continue;
auto section_storage = KBuffer::copy(section.raw_data(), section.size(), Region::Access::Read | Region::Access::Write | Region::Access::Execute);
section_storage_by_name.set(section.name(), section_storage.data());
module->sections.append(move(section_storage));
return IterationDecision::Continue;
});
bool missing_symbols = false;
elf_image->for_each_section_of_type(SHT_PROGBITS, [&](const ELF::Image::Section& section) {
if (!section.size())
return IterationDecision::Continue;
auto* section_storage = section_storage_by_name.get(section.name()).value_or(nullptr);
ASSERT(section_storage);
section.relocations().for_each_relocation([&](const ELF::Image::Relocation& relocation) {
auto& patch_ptr = *reinterpret_cast<ptrdiff_t*>(section_storage + relocation.offset());
switch (relocation.type()) {
case R_386_PC32: {
// PC-relative relocation
dbg() << "PC-relative relocation: " << relocation.symbol().name();
u32 symbol_address = address_for_kernel_symbol(relocation.symbol().name());
if (symbol_address == 0)
missing_symbols = true;
dbg() << " Symbol address: " << (void*)symbol_address;
ptrdiff_t relative_offset = (char*)symbol_address - ((char*)&patch_ptr + 4);
patch_ptr = relative_offset;
break;
}
case R_386_32: // Absolute relocation
dbg() << "Absolute relocation: '" << relocation.symbol().name() << "' value:" << relocation.symbol().value() << ", index:" << relocation.symbol_index();
if (relocation.symbol().bind() == STB_LOCAL) {
auto* section_storage_containing_symbol = section_storage_by_name.get(relocation.symbol().section().name()).value_or(nullptr);
ASSERT(section_storage_containing_symbol);
u32 symbol_address = (ptrdiff_t)(section_storage_containing_symbol + relocation.symbol().value());
if (symbol_address == 0)
missing_symbols = true;
dbg() << " Symbol address: " << (void*)symbol_address;
patch_ptr += symbol_address;
} else if (relocation.symbol().bind() == STB_GLOBAL) {
u32 symbol_address = address_for_kernel_symbol(relocation.symbol().name());
if (symbol_address == 0)
missing_symbols = true;
dbg() << " Symbol address: " << (void*)symbol_address;
patch_ptr += symbol_address;
} else {
ASSERT_NOT_REACHED();
}
break;
}
return IterationDecision::Continue;
});
return IterationDecision::Continue;
});
if (missing_symbols)
return -EINVAL;
auto* text_base = section_storage_by_name.get(".text").value_or(nullptr);
if (!text_base) {
dbg() << "No .text section found in module!";
return -EINVAL;
}
elf_image->for_each_symbol([&](const ELF::Image::Symbol& symbol) {
dbg() << " - " << symbol.type() << " '" << symbol.name() << "' @ " << (void*)symbol.value() << ", size=" << symbol.size();
if (symbol.name() == "module_init") {
module->module_init = (ModuleInitPtr)(text_base + symbol.value());
} else if (symbol.name() == "module_fini") {
module->module_fini = (ModuleFiniPtr)(text_base + symbol.value());
} else if (symbol.name() == "module_name") {
const u8* storage = section_storage_by_name.get(symbol.section().name()).value_or(nullptr);
if (storage)
module->name = String((const char*)(storage + symbol.value()));
}
return IterationDecision::Continue;
});
if (!module->module_init)
return -EINVAL;
if (g_modules->contains(module->name)) {
dbg() << "a module with the name " << module->name << " is already loaded; please unload it first";
return -EEXIST;
}
module->module_init();
auto name = module->name;
g_modules->set(name, move(module));
return 0;
}
int Process::sys$module_unload(const char* user_name, size_t name_length)
{
if (!is_superuser())
return -EPERM;
REQUIRE_NO_PROMISES;
auto module_name = validate_and_copy_string_from_user(user_name, name_length);
if (module_name.is_null())
return -EFAULT;
auto it = g_modules->find(module_name);
if (it == g_modules->end())
return -ENOENT;
if (it->value->module_fini)
it->value->module_fini();
g_modules->remove(it);
return 0;
}
}