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main.cc
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#include "mold.h"
#include "tbb/global_control.h"
#include "tbb/task_group.h"
#include <fcntl.h>
#include <functional>
#include <iostream>
#include <libgen.h>
#include <regex>
#include <signal.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include <unordered_set>
#define DAEMON_TIMEOUT 30
static tbb::task_group parser_tg;
static bool preloading;
static char *output_tmpfile;
static char *socket_tmpfile;
static bool is_text_file(MemoryMappedFile *mb) {
return mb->size() >= 4 &&
isprint(mb->data()[0]) &&
isprint(mb->data()[1]) &&
isprint(mb->data()[2]) &&
isprint(mb->data()[3]);
}
enum FileType { UNKNOWN, OBJ, DSO, AR, THIN_AR, TEXT };
static FileType get_file_type(MemoryMappedFile *mb) {
if (mb->size() >= 20 && memcmp(mb->data(), "\177ELF", 4) == 0) {
ElfEhdr &ehdr = *(ElfEhdr *)mb->data();
if (ehdr.e_type == ET_REL)
return OBJ;
if (ehdr.e_type == ET_DYN)
return DSO;
return UNKNOWN;
}
if (mb->size() >= 8 && memcmp(mb->data(), "!<arch>\n", 8) == 0)
return AR;
if (mb->size() >= 8 && memcmp(mb->data(), "!<thin>\n", 8) == 0)
return THIN_AR;
if (is_text_file(mb))
return TEXT;
return UNKNOWN;
}
static ObjectFile *new_object_file(MemoryMappedFile *mb, std::string archive_name) {
ObjectFile *file = new ObjectFile(mb, archive_name);
parser_tg.run([=]() { file->parse(); });
return file;
}
static SharedFile *new_shared_file(MemoryMappedFile *mb, bool as_needed) {
SharedFile *file = new SharedFile(mb, as_needed);
parser_tg.run([=]() { file->parse(); });
return file;
}
void read_file(MemoryMappedFile *mb, bool as_needed) {
typedef std::tuple<std::string, u64, u64> Key;
static std::map<Key, std::vector<ObjectFile *>> cache;
auto get_key = [](MemoryMappedFile *mb) -> Key {
return {mb->name, mb->size(), mb->mtime};
};
auto lookup = [&](MemoryMappedFile *mb) {
Key k = get_key(mb);
std::vector<ObjectFile *> objs = cache[k];
cache[k].clear();
return objs;
};
switch (get_file_type(mb)) {
case OBJ:
if (preloading) {
cache[get_key(mb)] = {new_object_file(mb, "")};
return;
}
if (std::vector<ObjectFile *> objs = lookup(mb); !objs.empty())
out::objs.push_back(objs[0]);
else
out::objs.push_back(new_object_file(mb, ""));
return;
case DSO:
out::dsos.push_back(new_shared_file(mb, as_needed));
return;
case AR:
if (preloading) {
for (MemoryMappedFile *child : read_fat_archive_members(mb))
cache[get_key(mb)].push_back(new_object_file(child, mb->name));
return;
}
if (std::vector<ObjectFile *> objs = lookup(mb); !objs.empty()) {
append(out::objs, objs);
} else {
for (MemoryMappedFile *child : read_archive_members(mb))
out::objs.push_back(new_object_file(child, mb->name));
}
return;
case THIN_AR:
if (preloading) {
for (MemoryMappedFile *child : read_thin_archive_members(mb))
cache[get_key(child)].push_back(new_object_file(child, mb->name));
return;
}
for (MemoryMappedFile *child : read_thin_archive_members(mb)) {
if (std::vector<ObjectFile *> objs = lookup(child); !objs.empty())
out::objs.push_back(objs[0]);
else
out::objs.push_back(new_object_file(child, mb->name));
}
return;
case TEXT:
parse_linker_script(mb, as_needed);
return;
default:
error(mb->name + ": unknown file type");
}
}
template <typename T>
static std::vector<std::span<T>> split(std::vector<T> &input, int unit) {
assert(input.size() > 0);
std::span<T> span(input);
std::vector<std::span<T>> vec;
while (span.size() >= unit) {
vec.push_back(span.subspan(0, unit));
span = span.subspan(unit);
}
if (!span.empty())
vec.push_back(span);
return vec;
}
static void resolve_symbols() {
ScopedTimer t("resolve_symbols");
// Register defined symbols
tbb::parallel_for_each(out::objs, [](ObjectFile *file) { file->resolve_symbols(); });
tbb::parallel_for_each(out::dsos, [](SharedFile *file) { file->resolve_symbols(); });
// Mark reachable objects and DSOs to decide which files to include
// into an output.
std::vector<ObjectFile *> root;
for (ObjectFile *file : out::objs)
if (file->is_alive)
root.push_back(file);
tbb::parallel_do(
root,
[&](ObjectFile *file, tbb::parallel_do_feeder<ObjectFile *> &feeder) {
for (ObjectFile *obj : file->mark_live_objects())
feeder.add(obj);
});
// Eliminate unused archive members and as-needed DSOs.
erase(out::objs, [](InputFile *file) { return !file->is_alive; });
erase(out::dsos, [](InputFile *file) { return !file->is_alive; });
}
static void eliminate_comdats() {
ScopedTimer t("comdat");
tbb::parallel_for_each(out::objs, [](ObjectFile *file) {
file->resolve_comdat_groups();
});
tbb::parallel_for_each(out::objs, [](ObjectFile *file) {
file->eliminate_duplicate_comdat_groups();
});
}
static void handle_mergeable_strings() {
ScopedTimer t("resolve_strings");
// Resolve mergeable string pieces
tbb::parallel_for_each(out::objs, [](ObjectFile *file) {
for (MergeableSection *m : file->mergeable_sections) {
for (StringPieceRef &ref : m->pieces) {
MergeableSection *cur = ref.piece->isec;
while (!cur || cur->file->priority > m->file->priority)
if (ref.piece->isec.compare_exchange_weak(cur, m))
break;
}
}
});
// Calculate the total bytes of mergeable strings for each input section.
tbb::parallel_for_each(out::objs, [](ObjectFile *file) {
for (MergeableSection *m : file->mergeable_sections) {
u32 offset = 0;
for (StringPieceRef &ref : m->pieces) {
StringPiece &piece = *ref.piece;
if (piece.isec == m && piece.output_offset == -1) {
ref.piece->output_offset = offset;
offset += ref.piece->size;
}
}
m->size = offset;
}
});
// Assign each mergeable input section a unique index.
for (ObjectFile *file : out::objs) {
for (MergeableSection *m : file->mergeable_sections) {
m->offset = m->parent.shdr.sh_size;
m->parent.shdr.sh_size += m->size;
}
}
}
// So far, each input section has a pointer to its corresponding
// output section, but there's no reverse edge to get a list of
// input sections from an output section. This function creates it.
//
// An output section may contain millions of input sections.
// So, we append input sections to output sections in parallel.
static void bin_sections() {
ScopedTimer t("bin_sections");
int unit = (out::objs.size() + 127) / 128;
std::vector<std::span<ObjectFile *>> slices = split(out::objs, unit);
int num_osec = OutputSection::instances.size();
std::vector<std::vector<std::vector<InputChunk *>>> groups(slices.size());
for (int i = 0; i < groups.size(); i++)
groups[i].resize(num_osec);
tbb::parallel_for(0, (int)slices.size(), [&](int i) {
for (ObjectFile *file : slices[i])
for (InputSection *isec : file->sections)
if (isec)
groups[i][isec->output_section->idx].push_back(isec);
});
std::vector<int> sizes(num_osec);
for (std::span<std::vector<InputChunk *>> group : groups)
for (int i = 0; i < group.size(); i++)
sizes[i] += group[i].size();
tbb::parallel_for(0, num_osec, [&](int j) {
OutputSection::instances[j]->members.reserve(sizes[j]);
for (int i = 0; i < groups.size(); i++)
append(OutputSection::instances[j]->members, groups[i][j]);
});
}
static void check_duplicate_symbols() {
ScopedTimer t("check_undef_syms");
auto is_error = [](ObjectFile *file, int i) {
const ElfSym &esym = file->elf_syms[i];
Symbol &sym = *file->symbols[i];
bool is_weak = (esym.st_bind == STB_WEAK);
bool is_eliminated =
!esym.is_abs() && !esym.is_common() && !file->sections[esym.st_shndx];
return esym.is_defined() && !is_weak && !is_eliminated && sym.file != file;
};
std::atomic_bool has_error = false;
tbb::parallel_for_each(out::objs, [&](ObjectFile *file) {
if (!file->is_alive)
return;
for (int i = file->first_global; i < file->elf_syms.size(); i++) {
if (is_error(file, i)) {
file->has_error = true;
has_error = true;
return;
}
}
});
for (ObjectFile *file : out::objs)
if (file->has_error)
for (int i = file->first_global; i < file->elf_syms.size(); i++)
if (is_error(file, i))
std::cerr << "duplicate symbol: " << to_string(file)
<< ": " << to_string(file->symbols[i]->file) << ": "
<< file->symbols[i]->name << "\n";
if (has_error)
_exit(1);
}
static void set_isec_offsets() {
ScopedTimer t("isec_offsets");
tbb::parallel_for_each(OutputSection::instances, [&](OutputSection *osec) {
if (osec->members.empty())
return;
std::vector<std::span<InputChunk *>> slices = split(osec->members, 10000);
std::vector<u64> size(slices.size());
std::vector<u32> alignments(slices.size());
tbb::parallel_for(0, (int)slices.size(), [&](int i) {
u64 off = 0;
u32 align = 1;
for (InputChunk *isec : slices[i]) {
off = align_to(off, isec->shdr.sh_addralign);
isec->offset = off;
off += isec->shdr.sh_size;
align = std::max<u32>(align, isec->shdr.sh_addralign);
}
size[i] = off;
alignments[i] = align;
});
u32 align = *std::max_element(alignments.begin(), alignments.end());
std::vector<u64> start(slices.size());
for (int i = 1; i < slices.size(); i++)
start[i] = align_to(start[i - 1] + size[i - 1], align);
tbb::parallel_for(1, (int)slices.size(), [&](int i) {
for (InputChunk *isec : slices[i])
isec->offset += start[i];
});
osec->shdr.sh_size = start.back() + size.back();
osec->shdr.sh_addralign = align;
});
}
static void scan_rels() {
ScopedTimer t("scan_rels");
// Scan relocations to find dynamic symbols.
tbb::parallel_for_each(out::objs, [&](ObjectFile *file) {
for (InputSection *isec : file->sections) {
if (isec)
isec->scan_relocations();
}
});
// If there was a relocation that refers an undefined symbol,
// report an error.
bool has_error = false;
for (ObjectFile *file : out::objs) {
if (file->has_error) {
has_error = true;
for (InputSection *isec : file->sections)
if (isec)
isec->report_undefined_symbols();
}
}
if (has_error)
_exit(1);
// Aggregate dynamic symbols to a single vector.
std::vector<InputFile *> files;
append(files, out::objs);
append(files, out::dsos);
std::vector<std::vector<Symbol *>> vec(files.size());
tbb::parallel_for(0, (int)files.size(), [&](int i) {
for (Symbol *sym : files[i]->symbols)
if (sym->file == files[i])
if (sym->flags)
vec[i].push_back(sym);
});
// Assign offsets in additional tables for each dynamic symbol.
for (Symbol *sym : flatten(vec)) {
if (sym->is_imported || (sym->flags & NEEDS_DYNSYM))
out::dynsym->add_symbol(sym);
if (sym->flags & NEEDS_GOT)
out::got->add_got_symbol(sym);
if (sym->flags & NEEDS_PLT)
out::plt->add_symbol(sym);
if (sym->flags & NEEDS_GOTTPOFF)
out::got->add_gottpoff_symbol(sym);
if (sym->flags & NEEDS_TLSGD)
out::got->add_tlsgd_symbol(sym);
if (sym->flags & NEEDS_TLSLD)
out::got->add_tlsld_symbol(sym);
if (sym->flags & NEEDS_COPYREL) {
out::copyrel->add_symbol(sym);
assert(sym->file->is_dso);
for (Symbol *alias : ((SharedFile *)sym->file)->find_aliases(sym)) {
if (sym == alias)
continue;
assert(alias->copyrel_offset == -1);
alias->copyrel_offset = sym->copyrel_offset;
out::dynsym->add_symbol(alias);
}
}
}
}
static void export_dynamic() {
ScopedTimer t("export_dynamic");
tbb::parallel_for(0, (int)out::objs.size(), [&](int i) {
ObjectFile *file = out::objs[i];
for (Symbol *sym : std::span(file->symbols).subspan(file->first_global))
if (sym->file == file && config.export_dynamic)
sym->ver_idx = VER_NDX_GLOBAL;
});
for (std::string_view name : config.globals)
Symbol::intern(name)->ver_idx = VER_NDX_GLOBAL;
std::vector<std::vector<Symbol *>> vec(out::objs.size());
tbb::parallel_for(0, (int)out::objs.size(), [&](int i) {
ObjectFile *file = out::objs[i];
for (Symbol *sym : std::span(file->symbols).subspan(file->first_global))
if (sym->file == file && sym->ver_idx != VER_NDX_LOCAL)
vec[i].push_back(sym);
});
for (Symbol *sym : flatten(vec))
out::dynsym->add_symbol(sym);
}
static void fill_symbol_versions() {
ScopedTimer t("fill_symbol_versions");
// Create a list of versioned symbols and sort by file and version.
std::vector<Symbol *> syms = out::dynsym->symbols;
erase(syms, [](Symbol *sym){ return sym->ver_idx < 2; });
if (syms.empty())
return;
sort(syms, [](Symbol *a, Symbol *b) {
return std::make_tuple(((SharedFile *)a->file)->soname, a->ver_idx) <
std::make_tuple(((SharedFile *)b->file)->soname, b->ver_idx);
});
// Compute sizes of .gnu.version and .gnu.version_r sections.
out::versym->contents.resize(out::dynsym->symbols.size() + 1, 1);
out::versym->contents[0] = 0;
int sz = sizeof(ElfVerneed) + sizeof(ElfVernaux);
for (int i = 1; i < syms.size(); i++) {
if (syms[i - 1]->file != syms[i]->file)
sz += sizeof(ElfVerneed) + sizeof(ElfVernaux);
else if (syms[i - 1]->ver_idx != syms[i]->ver_idx)
sz += sizeof(ElfVernaux);
}
out::verneed->contents.resize(sz);
// Fill .gnu.versoin_r.
u8 *buf = (u8 *)&out::verneed->contents[0];
u16 version = 1;
ElfVerneed *verneed = nullptr;
ElfVernaux *aux = nullptr;
auto add_aux = [&](Symbol *sym) {
SharedFile *file = (SharedFile *)sym->file;
std::string_view verstr = file->version_strings[sym->ver_idx];
verneed->vn_cnt += 1;
if (aux)
aux->vna_next = sizeof(ElfVernaux);
aux = (ElfVernaux *)buf;
buf += sizeof(*aux);
aux->vna_hash = elf_hash(verstr);
aux->vna_other = ++version;
aux->vna_name = out::dynstr->add_string(verstr);
};
auto add_verneed = [&](Symbol *sym) {
SharedFile *file = (SharedFile *)sym->file;
out::verneed->shdr.sh_info += 1;
if (verneed)
verneed->vn_next = buf - (u8 *)verneed;
verneed = (ElfVerneed *)buf;
buf += sizeof(*verneed);
verneed->vn_version = 1;
verneed->vn_file = out::dynstr->find_string(file->soname);
verneed->vn_aux = sizeof(ElfVerneed);
aux = nullptr;
add_aux(sym);
};
add_verneed(syms[0]);
out::versym->contents[syms[0]->dynsym_idx] = version;
for (int i = 1; i < syms.size(); i++) {
if (syms[i - 1]->file != syms[i]->file)
add_verneed(syms[i]);
else if (syms[i - 1]->ver_idx != syms[i]->ver_idx)
add_aux(syms[i]);
out::versym->contents[syms[i]->dynsym_idx] = version;
}
}
static void clear_padding(u64 filesize) {
ScopedTimer t("clear_padding");
auto zero = [](OutputChunk *chunk, u64 next_start) {
u64 pos = chunk->shdr.sh_offset;
if (chunk->shdr.sh_type != SHT_NOBITS)
pos += chunk->shdr.sh_size;
memset(out::buf + pos, 0, next_start - pos);
};
for (int i = 1; i < out::chunks.size(); i++)
zero(out::chunks[i - 1], out::chunks[i]->shdr.sh_offset);
zero(out::chunks.back(), filesize);
}
// We want to sort output sections in the following order.
//
// alloc readonly data
// alloc readonly code
// alloc writable tdata
// alloc writable tbss
// alloc writable data
// alloc writable bss
// nonalloc
static int get_section_rank(const ElfShdr &shdr) {
bool alloc = shdr.sh_flags & SHF_ALLOC;
bool writable = shdr.sh_flags & SHF_WRITE;
bool exec = shdr.sh_flags & SHF_EXECINSTR;
bool tls = shdr.sh_flags & SHF_TLS;
bool nobits = shdr.sh_type == SHT_NOBITS;
return (!alloc << 5) | (writable << 4) | (exec << 3) | (!tls << 2) | nobits;
}
static u64 set_osec_offsets(std::span<OutputChunk *> chunks) {
ScopedTimer t("osec_offset");
u64 fileoff = 0;
u64 vaddr = config.image_base;
for (OutputChunk *chunk : chunks) {
if (chunk->starts_new_ptload)
vaddr = align_to(vaddr, PAGE_SIZE);
if (vaddr % PAGE_SIZE > fileoff % PAGE_SIZE)
fileoff += vaddr % PAGE_SIZE - fileoff % PAGE_SIZE;
else if (vaddr % PAGE_SIZE < fileoff % PAGE_SIZE)
fileoff = align_to(fileoff, PAGE_SIZE) + vaddr % PAGE_SIZE;
fileoff = align_to(fileoff, chunk->shdr.sh_addralign);
vaddr = align_to(vaddr, chunk->shdr.sh_addralign);
chunk->shdr.sh_offset = fileoff;
if (chunk->shdr.sh_flags & SHF_ALLOC)
chunk->shdr.sh_addr = vaddr;
bool is_bss = chunk->shdr.sh_type == SHT_NOBITS;
if (!is_bss)
fileoff += chunk->shdr.sh_size;
bool is_tbss = is_bss && (chunk->shdr.sh_flags & SHF_TLS);
if (!is_tbss)
vaddr += chunk->shdr.sh_size;
}
return fileoff;
}
static void fix_synthetic_symbols(std::span<OutputChunk *> chunks) {
auto start = [](OutputChunk *chunk, Symbol *sym) {
if (sym) {
sym->shndx = chunk->shndx;
sym->value = chunk->shdr.sh_addr;
}
};
auto stop = [](OutputChunk *chunk, Symbol *sym) {
if (sym) {
sym->shndx = chunk->shndx;
sym->value = chunk->shdr.sh_addr + chunk->shdr.sh_size;
}
};
// __bss_start
for (OutputChunk *chunk : chunks) {
if (chunk->kind == OutputChunk::REGULAR && chunk->name == ".bss") {
start(chunk, out::__bss_start);
break;
}
}
// __ehdr_start
for (OutputChunk *chunk : chunks) {
if (chunk->shndx == 1) {
out::__ehdr_start->shndx = 1;
out::__ehdr_start->value = out::ehdr->shdr.sh_addr;
break;
}
}
// __rela_iplt_start and __rela_iplt_end
start(out::relplt, out::__rela_iplt_start);
stop(out::relplt, out::__rela_iplt_end);
// __{init,fini}_array_{start,end}
for (OutputChunk *chunk : chunks) {
switch (chunk->shdr.sh_type) {
case SHT_INIT_ARRAY:
start(chunk, out::__init_array_start);
stop(chunk, out::__init_array_end);
break;
case SHT_FINI_ARRAY:
start(chunk, out::__fini_array_start);
stop(chunk, out::__fini_array_end);
break;
}
}
// _end, end, _etext, etext, _edata and edata
for (OutputChunk *chunk : chunks) {
if (chunk->kind == OutputChunk::HEADER)
continue;
if (chunk->shdr.sh_flags & SHF_ALLOC)
stop(chunk, out::_end);
if (chunk->shdr.sh_flags & SHF_EXECINSTR)
stop(chunk, out::_etext);
if (chunk->shdr.sh_type != SHT_NOBITS && chunk->shdr.sh_flags & SHF_ALLOC)
stop(chunk, out::_edata);
}
// _DYNAMIC
if (out::dynamic)
start(out::dynamic, out::_DYNAMIC);
// _GLOBAL_OFFSET_TABLE_
if (out::gotplt)
start(out::gotplt, out::_GLOBAL_OFFSET_TABLE_);
// __start_ and __stop_ symbols
for (OutputChunk *chunk : chunks) {
if (is_c_identifier(chunk->name)) {
start(chunk, Symbol::intern("__start_" + std::string(chunk->name)));
stop(chunk, Symbol::intern("__stop_" + std::string(chunk->name)));
}
}
}
static u32 get_umask() {
u32 mask = umask(0);
umask(mask);
return mask;
}
void cleanup() {
if (output_tmpfile)
unlink(output_tmpfile);
if (socket_tmpfile)
unlink(socket_tmpfile);
}
static void signal_handler(int) {
cleanup();
_exit(1);
}
static u8 *open_output_file(u64 filesize) {
ScopedTimer t("open_file");
Counter counter("filesize", filesize);
std::string dir = dirname(strdup(config.output.c_str()));
output_tmpfile = strdup((dir + "/.mold-XXXXXX").c_str());
int fd = mkstemp(output_tmpfile);
if (fd == -1)
error("cannot open " + std::string(output_tmpfile) + ": " + strerror(errno));
if (rename(config.output.c_str(), output_tmpfile) == 0) {
close(fd);
fd = open(output_tmpfile, O_RDWR | O_CREAT, 0777);
if (fd == -1) {
if (errno != ETXTBSY)
error("cannot open " + config.output + ": " + strerror(errno));
unlink(output_tmpfile);
fd = open(output_tmpfile, O_RDWR | O_CREAT, 0777);
if (fd == -1)
error("cannot open " + config.output + ": " + strerror(errno));
}
}
if (ftruncate(fd, filesize))
error("ftruncate failed");
if (fchmod(fd, (0777 & ~get_umask())) == -1)
error("fchmod failed");
void *buf = mmap(nullptr, filesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (buf == MAP_FAILED)
error(config.output + ": mmap failed: " + strerror(errno));
close(fd);
if (config.filler != -1)
memset(buf, config.filler, filesize);
return (u8 *)buf;
}
MemoryMappedFile *find_library(std::string name, std::span<std::string_view> lib_paths) {
for (std::string_view dir : lib_paths) {
std::string root = dir.starts_with("/") ? config.sysroot : "";
std::string stem = root + std::string(dir) + "/lib" + name;
if (!config.is_static)
if (MemoryMappedFile *mb = MemoryMappedFile::open(stem + ".so"))
return mb;
if (MemoryMappedFile *mb = MemoryMappedFile::open(stem + ".a"))
return mb;
}
error("library not found: " + name);
}
static std::vector<std::string> add_dashes(std::string name) {
std::vector<std::string> opts;
opts.push_back("-" + name);
if (!name.starts_with("o"))
opts.push_back("--" + name);
return opts;
}
static bool read_arg(std::span<std::string_view> &args, std::string_view &arg,
std::string name) {
if (name.size() == 1) {
if (args[0] == "-" + name) {
if (args.size() == 1)
error("option -" + name + ": argument missing");
arg = args[1];
args = args.subspan(2);
return true;
}
if (args[0].starts_with("-" + name)) {
arg = args[0].substr(name.size() + 1);
args = args.subspan(1);
return true;
}
return false;
}
for (std::string opt : add_dashes(name)) {
if (args[0] == opt) {
if (args.size() == 1)
error("option " + name + ": argument missing");
arg = args[1];
args = args.subspan(2);
return true;
}
if (args[0].starts_with(opt + "=")) {
arg = args[0].substr(opt.size() + 1);
args = args.subspan(1);
return true;
}
}
return false;
}
static bool read_flag(std::span<std::string_view> &args, std::string name) {
for (std::string opt : add_dashes(name)) {
if (args[0] == opt) {
args = args.subspan(1);
return true;
}
}
return false;
}
static bool read_z_flag(std::span<std::string_view> &args, std::string name) {
if (args.size() >= 2 && args[0] == "-z" && args[1] == name) {
args = args.subspan(2);
return true;
}
if (!args.empty() && args[0] == "-z" + name) {
args = args.subspan(1);
return true;
}
return false;
}
static bool read_equal(std::span<std::string_view> &args, std::string_view &arg,
std::string name, std::string default_) {
for (std::string opt : add_dashes(name)) {
if (args[0] == opt) {
arg = default_;
args = args.subspan(1);
return true;
}
}
for (std::string opt : add_dashes(name)) {
if (args[0].starts_with(opt + "=")) {
arg = args[0].substr(opt.size() + 1);
args = args.subspan(1);
return true;
}
}
return false;
}
static u64 parse_hex(std::string opt, std::string_view value) {
if (!value.starts_with("0x") && !value.starts_with("0X"))
error("option -" + opt + ": not a hexadecimal number");
value = value.substr(2);
if (value.find_first_not_of("0123456789abcdefABCDEF") != std::string_view::npos)
error("option -" + opt + ": not a hexadecimal number");
return std::stol(std::string(value), nullptr, 16);
}
static u64 parse_number(std::string opt, std::string_view value) {
if (value.find_first_not_of("0123456789") != std::string_view::npos)
error("option -" + opt + ": not a number");
return std::stol(std::string(value));
}
// Exiting from a program with large memory usage is slow --
// it may take a few hundred milliseconds. To hide the latency,
// we fork a child and let it do the actual linking work.
static std::function<void()> fork_child() {
int pipefd[2];
if (pipe(pipefd) == -1) {
perror("pipe");
exit(1);
}
pid_t pid = fork();
if (pid == -1) {
perror("fork");
exit(1);
}
if (pid > 0) {
// Parent
close(pipefd[1]);
int r = read(pipefd[0], (char[1]){}, 1);
_exit(r != 1);
}
// Child
close(pipefd[0]);
return [=]() { write(pipefd[1], (char []){1}, 1); };
}
static std::string compute_sha1(char **argv) {
SHA1 sha1;
for (int i = 0; argv[i]; i++)
if (!strcmp(argv[i], "-preload") && !strcmp(argv[i], "--preload"))
sha1.update((u8 *)argv[i], strlen(argv[i]) + 1);
u8 digest[21];
memset(digest, 0, sizeof(digest));
sha1.get_result(digest);
static char chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
std::string res;
for (int i = 0; i < sizeof(digest); i += 3) {
u32 x = (digest[i + 2] << 16) | (digest[i + 1] << 8) | digest[i];
res += chars[x & 0b111111];
res += chars[(x >> 6) & 0b111111];
res += chars[(x >> 12) & 0b111111];
res += chars[(x >> 18) & 0b111111];
}
return res;
}
static void send_fd(int conn, int fd) {
struct iovec iov;
char dummy = '1';
iov.iov_base = &dummy;
iov.iov_len = 1;
struct msghdr msg;
memset(&msg, 0, sizeof(msg));
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
char buf[CMSG_SPACE(sizeof(int))];
msg.msg_control = buf;
msg.msg_controllen = CMSG_LEN(sizeof(int));
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
*(int *)CMSG_DATA(cmsg) = fd;
if (sendmsg(conn, &msg, 0) == -1)
error("sendmsg failed: " + std::string(strerror(errno)));
}
static int recv_fd(int conn) {
struct iovec iov;
char buf[1];
iov.iov_base = buf;
iov.iov_len = sizeof(buf);
struct msghdr msg;
memset(&msg, 0, sizeof(msg));
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
char cmsgbuf[CMSG_SPACE(sizeof(int))];
msg.msg_control = (caddr_t)cmsgbuf;
msg.msg_controllen = sizeof(cmsgbuf);
int len = recvmsg(conn, &msg, 0);
if (len <= 0)
error("recvmsg failed: " + std::string(strerror(errno)));
struct cmsghdr *cmsg;
cmsg = CMSG_FIRSTHDR(&msg);
return *(int *)CMSG_DATA(cmsg);
}
static int daemonize(char **argv) {
compute_sha1(argv);
if (daemon(1, 0) == -1)
error("daemon failed: " + std::string(strerror(errno)));
int sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock == -1)
error("socket failed: " + std::string(strerror(errno)));
socket_tmpfile = strdup(("/tmp/mold-" + compute_sha1(argv)).c_str());
struct sockaddr_un name;
memset(&name, 0, sizeof(name));
name.sun_family = AF_UNIX;
strcpy(name.sun_path, socket_tmpfile);
if (bind(sock, (struct sockaddr *)&name, sizeof(name)) == -1) {
if (errno != EADDRINUSE)
error("bind failed: " + std::string(strerror(errno)));
unlink(socket_tmpfile);
if (bind(sock, (struct sockaddr *)&name, sizeof(name)) == -1)
error("bind failed: " + std::string(strerror(errno)));
}
if (listen(sock, 0) == -1)
error("listen failed: " + std::string(strerror(errno)));
return sock;
}
static int wait_for_client(int sock) {
fd_set rfds;
FD_ZERO(&rfds);
FD_SET(sock, &rfds);
struct timeval tv;
tv.tv_sec = DAEMON_TIMEOUT;
tv.tv_usec = 0;
int res = select(sock + 1, &rfds, NULL, NULL, &tv);
if (res == -1)
error("select failed: " + std::string(strerror(errno)));
if (res == 0) {
std::cout << "timeout\n";
exit(0);
}
int conn = accept(sock, NULL, NULL);
if (conn == -1)
error("accept failed: " + std::string(strerror(errno)));
return conn;