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mirror of https://github.com/rui314/mold.git synced 2024-10-05 09:07:10 +03:00
mold/elf/linker-script.cc
Rui Ueyama 809652d740 [ELF] Handle glob patterns other than * for local: in version scripts
Previously, we didn't handle version scripts like this correctly:

  ver {
    global: *;
    local: foo*;
  }

We didn't handle `local:` part correctly except for `*`.

Fixes https://github.com/rui314/mold/issues/277
2022-01-20 08:51:04 +09:00

438 lines
12 KiB
C++

// On Linux, /usr/lib/x86_64-linux-gnu/libc.so is not actually
// a shared object file but an ASCII text file containing a linker
// script to include a "real" libc.so file. Therefore, we need to
// support a (very limited) subset of the linker script language.
#include "mold.h"
#include <cctype>
#include <iomanip>
namespace mold::elf {
template <typename E>
static thread_local MappedFile<Context<E>> *current_file;
template <typename E>
void read_version_script(Context<E> &ctx, std::span<std::string_view> &tok);
static std::string_view get_line(std::string_view input, const char *pos) {
assert(input.data() <= pos);
assert(pos < input.data() + input.size());
i64 start = input.rfind('\n', pos - input.data());
if (start == input.npos)
start = 0;
else
start++;
i64 end = input.find('\n', pos - input.data());
if (end == input.npos)
end = input.size();
return input.substr(start, end - start);
}
template <typename E>
class SyntaxError {
public:
SyntaxError(Context<E> &ctx, std::string_view errpos) : out(ctx) {
std::string_view contents = current_file<E>->get_contents();
std::string_view line = get_line(contents, errpos.data());
i64 lineno = 1;
for (i64 i = 0; contents.data() + i < line.data(); i++)
if (contents[i] == '\n')
lineno++;
i64 column = errpos.data() - line.data();
std::stringstream ss;
ss << current_file<E>->name << ":" << lineno << ": ";
i64 indent = (i64)ss.tellp() + strlen("mold: ");
ss << line << "\n" << std::setw(indent + column) << " " << "^ ";
out << ss.str();
}
template <class T> SyntaxError &operator<<(T &&val) {
out << std::forward<T>(val);
return *this;
}
[[noreturn]] ~SyntaxError() = default;
Fatal<Context<E>> out;
};
template <typename E>
static std::vector<std::string_view>
tokenize(Context<E> &ctx, std::string_view input) {
std::vector<std::string_view> vec;
while (!input.empty()) {
if (isspace(input[0])) {
input = input.substr(1);
continue;
}
if (input.starts_with("/*")) {
i64 pos = input.find("*/", 2);
if (pos == std::string_view::npos)
SyntaxError(ctx, input) << "unclosed comment";
input = input.substr(pos + 2);
continue;
}
if (input[0] == '#') {
i64 pos = input.find("\n", 1);
if (pos == std::string_view::npos)
break;
input = input.substr(pos + 1);
continue;
}
if (input[0] == '"') {
i64 pos = input.find('"', 1);
if (pos == std::string_view::npos)
SyntaxError(ctx, input) << "unclosed string literal";
vec.push_back(input.substr(0, pos + 1));
input = input.substr(pos + 1);
continue;
}
i64 pos = input.find_first_not_of(
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
"0123456789_.$/\\~=+[]*?-!^:");
if (pos == 0)
pos = 1;
else if (pos == input.npos)
pos = input.size();
vec.push_back(input.substr(0, pos));
input = input.substr(pos);
}
return vec;
}
template <typename E>
static std::span<std::string_view>
skip(Context<E> &ctx, std::span<std::string_view> tok, std::string_view str) {
if (tok.empty())
Fatal(ctx) << current_file<E>->name << ": expected '" << str
<< "', but got EOF";
if (tok[0] != str)
SyntaxError(ctx, tok[0]) << "expected '" << str << "'";
return tok.subspan(1);
}
static std::string_view unquote(std::string_view s) {
if (s.size() > 0 && s[0] == '"') {
assert(s[s.size() - 1] == '"');
return s.substr(1, s.size() - 2);
}
return s;
}
template <typename E>
static std::span<std::string_view>
read_output_format(Context<E> &ctx, std::span<std::string_view> tok) {
tok = skip(ctx, tok, "(");
while (!tok.empty() && tok[0] != ")")
tok = tok.subspan(1);
if (tok.empty())
Fatal(ctx) << current_file<E>->name << ": expected ')', but got EOF";
return tok.subspan(1);
}
template <typename E>
static bool is_in_sysroot(Context<E> &ctx, std::string path) {
std::string rel =
to_abs_path(path).lexically_relative(to_abs_path(ctx.arg.sysroot));
return rel != "." && !rel.starts_with("../");
}
template <typename E>
static MappedFile<Context<E>> *resolve_path(Context<E> &ctx, std::string_view tok) {
std::string str(unquote(tok));
// GNU ld prepends the sysroot if a pathname starts with '/' and the
// script being processed is in the sysroot. We do the same.
if (str.starts_with('/') && is_in_sysroot(ctx, current_file<E>->name))
return MappedFile<Context<E>>::must_open(ctx, ctx.arg.sysroot + str);
if (str.starts_with('=')) {
std::string path;
if (ctx.arg.sysroot.empty())
path = str.substr(1);
else
path = ctx.arg.sysroot + str.substr(1);
return MappedFile<Context<E>>::must_open(ctx, path);
}
if (str.starts_with("-l"))
return find_library(ctx, str.substr(2));
if (MappedFile<Context<E>> *mf = open_library(ctx, str))
return mf;
for (std::string_view dir : ctx.arg.library_paths) {
std::string path = std::string(dir) + "/" + str;
if (MappedFile<Context<E>> *mf = open_library(ctx, path))
return mf;
}
SyntaxError(ctx, tok) << "library not found: " << str;
}
template <typename E>
static std::span<std::string_view>
read_group(Context<E> &ctx, std::span<std::string_view> tok) {
tok = skip(ctx, tok, "(");
while (!tok.empty() && tok[0] != ")") {
if (tok[0] == "AS_NEEDED") {
bool orig = ctx.as_needed;
ctx.as_needed = true;
tok = read_group(ctx, tok.subspan(1));
ctx.as_needed = orig;
continue;
}
MappedFile<Context<E>> *mf = resolve_path(ctx, tok[0]);
read_file(ctx, mf);
tok = tok.subspan(1);
}
if (tok.empty())
Fatal(ctx) << current_file<E>->name << ": expected ')', but got EOF";
return tok.subspan(1);
}
template <typename E>
void parse_linker_script(Context<E> &ctx, MappedFile<Context<E>> *mf) {
current_file<E> = mf;
std::vector<std::string_view> vec = tokenize(ctx, mf->get_contents());
std::span<std::string_view> tok = vec;
while (!tok.empty()) {
if (tok[0] == "OUTPUT_FORMAT") {
tok = read_output_format(ctx, tok.subspan(1));
} else if (tok[0] == "INPUT" || tok[0] == "GROUP") {
tok = read_group(ctx, tok.subspan(1));
} else if (tok[0] == "VERSION") {
tok = tok.subspan(1);
tok = skip(ctx, tok, "{");
read_version_script(ctx, tok);
tok = skip(ctx, tok, "}");
} else if (tok[0] == ";") {
tok = tok.subspan(1);
} else {
SyntaxError(ctx, tok[0]) << "unknown linker script token";
}
}
}
template <typename E>
i64 get_script_output_type(Context<E> &ctx, MappedFile<Context<E>> *mf) {
current_file<E> = mf;
std::vector<std::string_view> vec = tokenize(ctx, mf->get_contents());
std::span<std::string_view> tok = vec;
if (tok.size() >= 3 && tok[0] == "OUTPUT_FORMAT" && tok[1] == "(") {
if (tok[2] == "elf64-x86-64")
return EM_X86_64;
if (tok[2] == "elf32-i386")
return EM_386;
}
return -1;
}
static bool read_label(std::span<std::string_view> &tok,
std::string label) {
if (tok.size() >= 1 && tok[0] == label + ":") {
tok = tok.subspan(1);
return true;
}
if (tok.size() >= 2 && tok[0] == label && tok[1] == ":") {
tok = tok.subspan(2);
return true;
}
return false;
}
template <typename E>
static void
read_version_script_commands(Context<E> &ctx, std::span<std::string_view> &tok,
VersionPattern &pat, VersionPattern &local_pat,
bool is_cpp) {
bool is_global = true;
while (!tok.empty() && tok[0] != "}") {
if (read_label(tok, "global")) {
is_global = true;
continue;
}
if (read_label(tok, "local")) {
is_global = false;
continue;
}
if (tok[0] == "extern") {
tok = tok.subspan(1);
if (!tok.empty() && tok[0] == "\"C\"") {
tok = tok.subspan(1);
tok = skip(ctx, tok, "{");
read_version_script_commands(ctx, tok, pat, local_pat, false);
} else {
tok = skip(ctx, tok, "\"C++\"");
tok = skip(ctx, tok, "{");
read_version_script_commands(ctx, tok, pat, local_pat, true);
}
tok = skip(ctx, tok, "}");
tok = skip(ctx, tok, ";");
continue;
}
if (tok[0] == "*") {
ctx.default_version = (is_global ? pat.ver_idx : VER_NDX_LOCAL);
} else if (is_global) {
if (is_cpp)
pat.cpp_patterns.push_back(unquote(tok[0]));
else
pat.patterns.push_back(unquote(tok[0]));
} else {
if (is_cpp)
local_pat.cpp_patterns.push_back(unquote(tok[0]));
else
local_pat.patterns.push_back(unquote(tok[0]));
}
tok = tok.subspan(1);
if (!tok.empty() && tok[0] == "}")
return;
tok = skip(ctx, tok, ";");
}
}
template <typename E>
void read_version_script(Context<E> &ctx, std::span<std::string_view> &tok) {
u16 next_ver = VER_NDX_LAST_RESERVED + ctx.arg.version_definitions.size() + 1;
while (!tok.empty() && tok[0] != "}") {
VersionPattern pat;
if (tok[0] == "{") {
pat.ver_idx = VER_NDX_GLOBAL;
} else {
pat.ver_idx = next_ver++;
ctx.arg.version_definitions.push_back(std::string(tok[0]));
tok = tok.subspan(1);
}
VersionPattern local_pat;
local_pat.ver_idx = VER_NDX_LOCAL;
tok = skip(ctx, tok, "{");
read_version_script_commands(ctx, tok, pat, local_pat, false);
tok = skip(ctx, tok, "}");
if (!tok.empty() && tok[0] != ";")
tok = tok.subspan(1);
tok = skip(ctx, tok, ";");
ctx.version_patterns.push_back(pat);
if (!local_pat.patterns.empty() || !local_pat.cpp_patterns.empty())
ctx.version_patterns.push_back(local_pat);
}
}
template <typename E>
void parse_version_script(Context<E> &ctx, std::string path) {
current_file<E> = MappedFile<Context<E>>::must_open(ctx, path);
std::vector<std::string_view> vec =
tokenize(ctx, current_file<E>->get_contents());
std::span<std::string_view> tok = vec;
read_version_script(ctx, tok);
if (!tok.empty())
SyntaxError(ctx, tok[0]) << "trailing garbage token";
}
template <typename E>
void read_dynamic_list_commands(Context<E> &ctx,
std::span<std::string_view> &tok,
VersionPattern &pat,
bool is_cpp) {
while (!tok.empty() && tok[0] != "}") {
if (tok[0] == "extern") {
tok = tok.subspan(1);
if (!tok.empty() && tok[0] == "\"C\"") {
tok = tok.subspan(1);
tok = skip(ctx, tok, "{");
read_dynamic_list_commands(ctx, tok, pat, false);
} else {
tok = skip(ctx, tok, "\"C++\"");
tok = skip(ctx, tok, "{");
read_dynamic_list_commands(ctx, tok, pat, true);
}
tok = skip(ctx, tok, "}");
tok = skip(ctx, tok, ";");
continue;
}
if (tok[0] == "*")
ctx.default_version = VER_NDX_GLOBAL;
else if (is_cpp)
pat.cpp_patterns.push_back(unquote(tok[0]));
else
pat.patterns.push_back(unquote(tok[0]));
tok = skip(ctx, tok.subspan(1), ";");
}
}
template <typename E>
void parse_dynamic_list(Context<E> &ctx, std::string path) {
current_file<E> = MappedFile<Context<E>>::must_open(ctx, path);
std::vector<std::string_view> vec =
tokenize(ctx, current_file<E>->get_contents());
std::span<std::string_view> tok = vec;
tok = skip(ctx, tok, "{");
VersionPattern pat;
pat.ver_idx = VER_NDX_GLOBAL;
read_dynamic_list_commands(ctx, tok, pat, false);
ctx.version_patterns.push_back(pat);
tok = skip(ctx, tok, "}");
tok = skip(ctx, tok, ";");
if (!tok.empty())
SyntaxError(ctx, tok[0]) << "trailing garbage token";
}
#define INSTANTIATE(E) \
template \
void parse_linker_script(Context<E> &ctx, MappedFile<Context<E>> *mf); \
template \
i64 get_script_output_type(Context<E> &ctx, MappedFile<Context<E>> *mf); \
template \
void parse_version_script(Context<E> &ctx, std::string path); \
template \
void parse_dynamic_list(Context<E> &ctx, std::string path)
INSTANTIATE(X86_64);
INSTANTIATE(I386);
INSTANTIATE(ARM64);
} // namespace mold::elf