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LibELF: Use StringView instead of "const char*" in dynamic linker code

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There's no reason to use C strings more than absolutely necessary.
This commit is contained in:
Andreas Kling 2021-02-20 19:20:08 +01:00
parent 2c3f284b06
commit 0c0127dc3f
6 changed files with 36 additions and 41 deletions
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33
Userland/Libraries/LibELF/DynamicObject.cpp
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@ -31,7 +31,6 @@
#include <LibELF/DynamicLinker.h>
#include <LibELF/DynamicObject.h>
#include <LibELF/exec_elf.h>
#include <stdio.h>
#include <string.h>
namespace ELF {
@ -71,7 +70,7 @@ void DynamicObject::dump() const
});
if (m_has_soname)
builder.appendf("DT_SONAME: %s\n", soname()); // FIXME: Valdidate that this string is null terminated?
builder.appendff("DT_SONAME: {}\n", soname()); // FIXME: Valdidate that this string is null terminated?
dbgln_if(DYNAMIC_LOAD_DEBUG, "Dynamic section at address {} contains {} entries:", m_dynamic_address.as_ptr(), num_dynamic_sections);
dbgln_if(DYNAMIC_LOAD_DEBUG, "{}", builder.string_view());
@ -249,17 +248,16 @@ const DynamicObject::RelocationSection DynamicObject::plt_relocation_section() c
return RelocationSection(Section(*this, m_plt_relocation_offset_location, m_size_of_plt_relocation_entry_list, m_size_of_relocation_entry, "DT_JMPREL"));
}
u32 DynamicObject::HashSection::calculate_elf_hash(const char* name) const
u32 DynamicObject::HashSection::calculate_elf_hash(const StringView& name) const
{
// SYSV ELF hash algorithm
// Note that the GNU HASH algorithm has less collisions
uint32_t hash = 0;
while (*name != '\0') {
for (auto ch : name) {
hash = hash << 4;
hash += *name;
name++;
hash += ch;
const uint32_t top_nibble_of_hash = hash & 0xF0000000U;
hash ^= top_nibble_of_hash >> 24;
@ -269,24 +267,23 @@ u32 DynamicObject::HashSection::calculate_elf_hash(const char* name) const
return hash;
}
u32 DynamicObject::HashSection::calculate_gnu_hash(const char* name) const
u32 DynamicObject::HashSection::calculate_gnu_hash(const StringView& name) const
{
// GNU ELF hash algorithm
u32 hash = 5381;
for (; *name != '\0'; ++name) {
hash = hash * 33 + *name;
}
for (auto ch : name)
hash = hash * 33 + ch;
return hash;
}
const DynamicObject::Symbol DynamicObject::HashSection::lookup_symbol(const char* name) const
auto DynamicObject::HashSection::lookup_symbol(const StringView& name) const -> Symbol
{
return (this->*(m_lookup_function))(name);
}
const DynamicObject::Symbol DynamicObject::HashSection::lookup_elf_symbol(const char* name) const
const DynamicObject::Symbol DynamicObject::HashSection::lookup_elf_symbol(const StringView& name) const
{
u32 hash_value = calculate_elf_hash(name);
@ -305,7 +302,7 @@ const DynamicObject::Symbol DynamicObject::HashSection::lookup_elf_symbol(const
for (u32 i = buckets[hash_value % num_buckets]; i; i = chains[i]) {
auto symbol = m_dynamic.symbol(i);
if (strcmp(name, symbol.name()) == 0) {
if (name == symbol.name()) {
dbgln_if(DYNAMIC_LOAD_DEBUG, "Returning SYSV dynamic symbol with index {} for {}: {}", i, symbol.name(), symbol.address().as_ptr());
return symbol;
}
@ -313,7 +310,7 @@ const DynamicObject::Symbol DynamicObject::HashSection::lookup_elf_symbol(const
return Symbol::create_undefined(m_dynamic);
}
const DynamicObject::Symbol DynamicObject::HashSection::lookup_gnu_symbol(const char* name) const
const DynamicObject::Symbol DynamicObject::HashSection::lookup_gnu_symbol(const StringView& name) const
{
// Algorithm reference: https://ent-voy.blogspot.com/2011/02/
// TODO: Handle 64bit bloomwords for ELF_CLASS64
@ -350,7 +347,7 @@ const DynamicObject::Symbol DynamicObject::HashSection::lookup_gnu_symbol(const
for (hash1 &= ~1;; ++current_sym) {
hash2 = *(current_chain++);
const auto symbol = m_dynamic.symbol(current_sym);
if ((hash1 == (hash2 & ~1)) && strcmp(name, symbol.name()) == 0) {
if ((hash1 == (hash2 & ~1)) && name == symbol.name()) {
dbgln_if(DYNAMIC_LOAD_DEBUG, "Returning GNU dynamic symbol with index {} for {}: {}", current_sym, symbol.name(), symbol.address().as_ptr());
return symbol;
}
@ -362,9 +359,9 @@ const DynamicObject::Symbol DynamicObject::HashSection::lookup_gnu_symbol(const
return Symbol::create_undefined(m_dynamic);
}
const char* DynamicObject::symbol_string_table_string(Elf32_Word index) const
StringView DynamicObject::symbol_string_table_string(Elf32_Word index) const
{
return (const char*)base_address().offset(m_string_table_offset + index).as_ptr();
return StringView { (const char*)base_address().offset(m_string_table_offset + index).as_ptr() };
}
DynamicObject::InitializationFunction DynamicObject::init_section_function() const
@ -465,7 +462,7 @@ static const char* name_for_dtag(Elf32_Sword d_tag)
}
}
Optional<DynamicObject::SymbolLookupResult> DynamicObject::lookup_symbol(const char* name) const
Optional<DynamicObject::SymbolLookupResult> DynamicObject::lookup_symbol(const StringView& name) const
{
auto res = hash_section().lookup_symbol(name);
if (res.is_undefined())