binutils-gdb/gold/archive.cc

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// archive.cc -- archive support for gold
#include "gold.h"
#include <cerrno>
#include <cstring>
#include <climits>
#include <vector>
#include "elfcpp.h"
#include "fileread.h"
#include "symtab.h"
#include "object.h"
#include "archive.h"
namespace gold
{
// The header of an entry in the archive. This is all readable text,
// padded with spaces where necesary. If the contents of an archive
// are all text file, the entire archive is readable.
struct Archive::Archive_header
{
// The entry name.
char ar_name[16];
// The file modification time.
char ar_date[12];
// The user's UID in decimal.
char ar_uid[6];
// The user's GID in decimal.
char ar_gid[6];
// The file mode in octal.
char ar_mode[8];
// The file size in decimal.
char ar_size[10];
// The final magic code.
char ar_fmag[2];
};
// Archive methods.
const char Archive::armag[sarmag] =
{
'!', '<', 'a', 'r', 'c', 'h', '>', '\n'
};
const char Archive::arfmag[2] = { '`', '\n' };
// Get a view into the underlying file.
const unsigned char*
Archive::get_view(off_t start, off_t size)
{
return this->input_file_->file().get_view(start, size);
}
// Set up the archive: read the symbol map and the extended name
// table.
void
Archive::setup()
{
// The first member of the archive should be the symbol table.
std::string armap_name;
off_t armap_size = this->read_header(sarmag, &armap_name);
if (!armap_name.empty())
{
fprintf(stderr, _("%s: %s: no archive symbol table (run ranlib)\n"),
program_name, this->name().c_str());
gold_exit(false);
}
// Read in the entire armap.
const unsigned char* p = this->get_view(sarmag + sizeof(Archive_header),
armap_size);
// Numbers in the armap are always big-endian.
const elfcpp::Elf_Word* pword = reinterpret_cast<const elfcpp::Elf_Word*>(p);
unsigned int nsyms = elfcpp::read_elf_word<true>(pword);
++pword;
// Note that the addition is in units of sizeof(elfcpp::Elf_Word).
const char* pnames = reinterpret_cast<const char*>(pword + nsyms);
this->armap_.resize(nsyms);
for (unsigned int i = 0; i < nsyms; ++i)
{
this->armap_[i].name = pnames;
this->armap_[i].offset = elfcpp::read_elf_word<true>(pword);
pnames += strlen(pnames) + 1;
++pword;
}
if (reinterpret_cast<const unsigned char*>(pnames) - p > armap_size)
{
fprintf(stderr, _("%s: %s: bad archive symbol table names\n"),
program_name, this->name().c_str());
gold_exit(false);
}
// See if there is an extended name table.
off_t off = sarmag + sizeof(Archive_header) + armap_size;
if ((off & 1) != 0)
++off;
std::string xname;
off_t extended_size = this->read_header(off, &xname);
if (xname == "/")
{
p = this->get_view(off + sizeof(Archive_header), extended_size);
const char* px = reinterpret_cast<const char*>(p);
this->extended_names_.assign(px, extended_size);
}
// Opening the file locked it. Unlock it now.
this->input_file_->file().unlock();
}
// Read the header of an archive member at OFF. Fail if something
// goes wrong. Return the size of the member. Set *PNAME to the name
// of the member.
off_t
Archive::read_header(off_t off, std::string* pname)
{
const unsigned char* p = this->get_view(off, sizeof(Archive_header));
const Archive_header* hdr = reinterpret_cast<const Archive_header*>(p);
if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0)
{
fprintf(stderr, _("%s; %s: malformed archive header at %ld\n"),
program_name, this->name().c_str(),
static_cast<long>(off));
gold_exit(false);
}
const int size_string_size = sizeof hdr->ar_size;
char size_string[size_string_size + 1];
memcpy(size_string, hdr->ar_size, size_string_size);
char* ps = size_string + size_string_size;
while (ps[-1] == ' ')
--ps;
*ps = '\0';
errno = 0;
char* end;
off_t member_size = strtol(size_string, &end, 10);
if (*end != '\0'
|| member_size < 0
|| (member_size == LONG_MAX && errno == ERANGE))
{
fprintf(stderr, _("%s: %s: malformed archive header size at %ld\n"),
program_name, this->name().c_str(),
static_cast<long>(off));
gold_exit(false);
}
if (hdr->ar_name[0] != '/')
{
const char* name_end = strchr(hdr->ar_name, '/');
if (name_end == NULL
|| name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name))
{
fprintf(stderr, _("%s: %s: malformed archive header name at %ld\n"),
program_name, this->name().c_str(),
static_cast<long>(off));
gold_exit(false);
}
pname->assign(hdr->ar_name, name_end - hdr->ar_name);
}
else if (hdr->ar_name[1] == ' ')
{
// This is the symbol table.
pname->clear();
}
else if (hdr->ar_name[1] == '/')
{
// This is the extended name table.
pname->assign(1, '/');
}
else
{
errno = 0;
long x = strtol(hdr->ar_name + 1, &end, 10);
if (*end != ' '
|| x < 0
|| (x == LONG_MAX && errno == ERANGE)
|| static_cast<size_t>(x) >= this->extended_names_.size())
{
fprintf(stderr, _("%s: %s: bad extended name index at %ld\n"),
program_name, this->name().c_str(),
static_cast<long>(off));
gold_exit(false);
}
const char* name = this->extended_names_.data() + x;
const char* name_end = strchr(name, '/');
if (static_cast<size_t>(name_end - name) > this->extended_names_.size()
|| name_end[1] != '\n')
{
fprintf(stderr, _("%s: %s: bad extended name entry at header %ld\n"),
program_name, this->name().c_str(),
static_cast<long>(off));
gold_exit(false);
}
pname->assign(name, name_end - name);
}
return member_size;
}
// Select members from the archive and add them to the link. We walk
// through the elements in the archive map, and look each one up in
// the symbol table. If it exists as a strong undefined symbol, we
// pull in the corresponding element. We have to do this in a loop,
// since pulling in one element may create new undefined symbols which
// may be satisfied by other objects in the archive.
void
Archive::add_symbols(Symbol_table* symtab, Layout* layout,
Input_objects* input_objects)
{
size_t armap_size = this->armap_.size();
std::vector<bool> seen;
seen.resize(this->armap_.size());
seen.clear();
bool added_new_object;
do
{
added_new_object = false;
off_t last = -1;
for (size_t i = 0; i < armap_size; ++i)
{
if (seen[i])
continue;
if (this->armap_[i].offset == last)
{
seen[i] = true;
continue;
}
Symbol* sym = symtab->lookup(this->armap_[i].name);
if (sym == NULL)
continue;
else if (sym->shnum() != elfcpp::SHN_UNDEF)
{
seen[i] = true;
continue;
}
else if (sym->binding() == elfcpp::STB_WEAK)
continue;
// We want to include this object in the link.
last = this->armap_[i].offset;
this->include_member(symtab, layout, input_objects, last);
added_new_object = true;
}
}
while (added_new_object);
}
// Include an archive member in the link. OFF is the file offset of
// the member header.
void
Archive::include_member(Symbol_table* symtab, Layout* layout,
Input_objects* input_objects, off_t off)
{
std::string n;
this->read_header(off, &n);
size_t memoff = off + sizeof(Archive_header);
// Read enough of the file to pick up the entire ELF header.
int ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
off_t bytes;
const unsigned char* p = this->input_file_->file().get_view(memoff,
ehdr_size,
&bytes);
if (bytes < 4)
{
fprintf(stderr, _("%s: %s: member at %ld is not an ELF object"),
program_name, this->name().c_str(),
static_cast<long>(off));
gold_exit(false);
}
static unsigned char elfmagic[4] =
{
elfcpp::ELFMAG0, elfcpp::ELFMAG1,
elfcpp::ELFMAG2, elfcpp::ELFMAG3
};
if (memcmp(p, elfmagic, 4) != 0)
{
fprintf(stderr, _("%s: %s: member at %ld is not an ELF object"),
program_name, this->name().c_str(),
static_cast<long>(off));
gold_exit(false);
}
Object* obj = make_elf_object((std::string(this->input_file_->filename())
+ "(" + n + ")"),
this->input_file_, memoff, p, bytes);
input_objects->add_object(obj);
Read_symbols_data sd;
obj->read_symbols(&sd);
obj->layout(layout, &sd);
obj->add_symbols(symtab, &sd);
}
// Add_archive_symbols methods.
Add_archive_symbols::~Add_archive_symbols()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the next
// input file.
}
// Return whether we can add the archive symbols. We are blocked by
// this_blocker_. We block next_blocker_. We also lock the file.
Task::Is_runnable_type
Add_archive_symbols::is_runnable(Workqueue*)
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return IS_BLOCKED;
return IS_RUNNABLE;
}
class Add_archive_symbols::Add_archive_symbols_locker : public Task_locker
{
public:
Add_archive_symbols_locker(Task_token& token, Workqueue* workqueue,
Archive* archive)
: blocker_(token, workqueue), archlock_(*archive)
{ }
private:
Task_locker_block blocker_;
Task_locker_obj<Archive> archlock_;
};
Task_locker*
Add_archive_symbols::locks(Workqueue* workqueue)
{
return new Add_archive_symbols_locker(*this->next_blocker_,
workqueue,
this->archive_);
}
void
Add_archive_symbols::run(Workqueue*)
{
this->archive_->add_symbols(this->symtab_, this->layout_,
this->input_objects_);
}
} // End namespace gold.