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mirror of https://github.com/rui314/mold.git synced 2024-11-14 16:31:42 +03:00
mold/archive-file.h
2021-10-05 11:24:48 +09:00

171 lines
3.9 KiB
C++

#pragma once
#include "mold.h"
namespace mold {
struct ArHdr {
char ar_name[16];
char ar_date[12];
char ar_uid[6];
char ar_gid[6];
char ar_mode[8];
char ar_size[10];
char ar_fmag[2];
};
enum class FileType {
UNKNOWN,
ELF_OBJ,
ELF_DSO,
MACH_OBJ,
MACH_DYLIB,
AR,
THIN_AR,
TEXT,
LLVM_BITCODE,
};
template <typename C>
bool is_text_file(MappedFile<C> *mf) {
u8 *data = mf->data;
return mf->size >= 4 && isprint(data[0]) && isprint(data[1]) &&
isprint(data[2]) && isprint(data[3]);
}
template <typename C>
FileType get_file_type(MappedFile<C> *mf) {
std::string_view data = mf->get_contents();
if (data.starts_with("\177ELF")) {
switch (*(u16 *)(data.data() + 16)) {
case 1: // ET_REL
return FileType::ELF_OBJ;
case 3: // ET_DYN
return FileType::ELF_DSO;
}
return FileType::UNKNOWN;
}
if (data.starts_with("\xcf\xfa\xed\xfe")) {
switch (*(u32 *)(data.data() + 12)) {
case 1: // MH_OBJECT
return FileType::MACH_OBJ;
case 6: // MH_DYLIB
return FileType::MACH_DYLIB;
}
return FileType::UNKNOWN;
}
if (data.starts_with("!<arch>\n"))
return FileType::AR;
if (data.starts_with("!<thin>\n"))
return FileType::THIN_AR;
if (is_text_file(mf))
return FileType::TEXT;
if (data.starts_with("\xDE\xC0\x17\x0B"))
return FileType::LLVM_BITCODE;
if (data.starts_with("BC\xC0\xDE"))
return FileType::LLVM_BITCODE;
return FileType::UNKNOWN;
}
template <typename C>
std::vector<MappedFile<C> *>
read_thin_archive_members(C &ctx, MappedFile<C> *mf) {
u8 *begin = mf->data;
u8 *data = begin + 8;
std::vector<MappedFile<C> *> vec;
std::string_view strtab;
while (data < begin + mf->size) {
// Each header is aligned to a 2 byte boundary.
if ((begin - data) % 2)
data++;
ArHdr &hdr = *(ArHdr *)data;
u8 *body = data + sizeof(hdr);
u64 size = atol(hdr.ar_size);
// Read a string table.
if (!memcmp(hdr.ar_name, "// ", 3)) {
strtab = {(char *)body, size};
data = body + size;
continue;
}
// Skip a symbol table.
if (!memcmp(hdr.ar_name, "/ ", 2)) {
data = body + size;
continue;
}
if (hdr.ar_name[0] != '/')
Fatal(ctx) << mf->name << ": filename is not stored as a long filename";
const char *start = strtab.data() + atoi(hdr.ar_name + 1);
std::string name(start, (const char *)strstr(start, "/\n"));
std::string path = name.starts_with('/') ?
name : std::string(path_dirname(mf->name)) + "/" + name;
vec.push_back(MappedFile<C>::must_open(ctx, path));
data = body;
}
return vec;
}
template <typename C>
std::vector<MappedFile<C> *>
read_fat_archive_members(C &ctx, MappedFile<C> *mf) {
u8 *begin = mf->data;
u8 *data = begin + 8;
std::vector<MappedFile<C> *> vec;
std::string_view strtab;
while (begin + mf->size - data >= 2) {
if ((begin - data) % 2)
data++;
ArHdr &hdr = *(ArHdr *)data;
u8 *body = data + sizeof(hdr);
u64 size = atol(hdr.ar_size);
data = body + size;
if (!memcmp(hdr.ar_name, "// ", 3)) {
strtab = {(char *)body, size};
continue;
}
if (!memcmp(hdr.ar_name, "/ ", 2) ||
!memcmp(hdr.ar_name, "__.SYMDEF/", 10))
continue;
std::string name;
if (hdr.ar_name[0] == '/') {
const char *start = strtab.data() + atoi(hdr.ar_name + 1);
name = {start, (const char *)strstr(start, "/\n")};
} else {
name = {hdr.ar_name, strchr(hdr.ar_name, '/')};
}
vec.push_back(mf->slice(ctx, name, body - begin, size));
}
return vec;
}
template <typename C>
std::vector<MappedFile<C> *>
read_archive_members(C &ctx, MappedFile<C> *mf) {
switch (get_file_type(mf)) {
case FileType::AR:
return read_fat_archive_members(ctx, mf);
case FileType::THIN_AR:
return read_thin_archive_members(ctx, mf);
default:
unreachable();
}
}
} // namespace mold