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// Inferno utils/include/ar.h
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/include/ar.h
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package ld
import (
"cmd/internal/bio"
"cmd/internal/objabi"
"cmd/link/internal/sym"
"encoding/binary"
"fmt"
"io"
"os"
)
const (
SARMAG = 8
SAR_HDR = 16 + 44
)
const (
ARMAG = "!<arch>\n"
)
type ArHdr struct {
name string
date string
uid string
gid string
mode string
size string
fmag string
}
// hostArchive reads an archive file holding host objects and links in
// required objects. The general format is the same as a Go archive
// file, but it has an armap listing symbols and the objects that
// define them. This is used for the compiler support library
// libgcc.a.
func hostArchive(ctxt *Link, name string) {
f, err := bio.Open(name)
if err != nil {
if os.IsNotExist(err) {
// It's OK if we don't have a libgcc file at all.
if ctxt.Debugvlog != 0 {
ctxt.Logf("skipping libgcc file: %v\n", err)
}
return
}
Exitf("cannot open file %s: %v", name, err)
}
defer f.Close()
var magbuf [len(ARMAG)]byte
if _, err := io.ReadFull(f, magbuf[:]); err != nil {
Exitf("file %s too short", name)
}
if string(magbuf[:]) != ARMAG {
Exitf("%s is not an archive file", name)
}
var arhdr ArHdr
l := nextar(f, f.Offset(), &arhdr)
if l <= 0 {
Exitf("%s missing armap", name)
}
var armap archiveMap
if arhdr.name == "/" || arhdr.name == "/SYM64/" {
armap = readArmap(name, f, arhdr)
} else {
Exitf("%s missing armap", name)
}
loaded := make(map[uint64]bool)
any := true
for any {
var load []uint64
for _, s := range ctxt.Syms.Allsym {
for i := range s.R {
r := &s.R[i] // Copying sym.Reloc has measurable impact on performance
if r.Sym != nil && r.Sym.Type == sym.SXREF {
if off := armap[r.Sym.Name]; off != 0 && !loaded[off] {
load = append(load, off)
loaded[off] = true
}
}
}
}
for _, off := range load {
l := nextar(f, int64(off), &arhdr)
if l <= 0 {
Exitf("%s missing archive entry at offset %d", name, off)
}
pname := fmt.Sprintf("%s(%s)", name, arhdr.name)
l = atolwhex(arhdr.size)
libgcc := sym.Library{Pkg: "libgcc"}
h := ldobj(ctxt, f, &libgcc, l, pname, name)
f.MustSeek(h.off, 0)
h.ld(ctxt, f, h.pkg, h.length, h.pn)
}
any = len(load) > 0
}
}
// archiveMap is an archive symbol map: a mapping from symbol name to
// offset within the archive file.
type archiveMap map[string]uint64
// readArmap reads the archive symbol map.
func readArmap(filename string, f *bio.Reader, arhdr ArHdr) archiveMap {
is64 := arhdr.name == "/SYM64/"
wordSize := 4
if is64 {
wordSize = 8
}
contents := make([]byte, atolwhex(arhdr.size))
if _, err := io.ReadFull(f, contents); err != nil {
Exitf("short read from %s", filename)
}
var c uint64
if is64 {
c = binary.BigEndian.Uint64(contents)
} else {
c = uint64(binary.BigEndian.Uint32(contents))
}
contents = contents[wordSize:]
ret := make(archiveMap)
names := contents[c*uint64(wordSize):]
for i := uint64(0); i < c; i++ {
n := 0
for names[n] != 0 {
n++
}
name := string(names[:n])
names = names[n+1:]
// For Mach-O and PE/386 files we strip a leading
// underscore from the symbol name.
if objabi.GOOS == "darwin" || (objabi.GOOS == "windows" && objabi.GOARCH == "386") {
if name[0] == '_' && len(name) > 1 {
name = name[1:]
}
}
var off uint64
if is64 {
off = binary.BigEndian.Uint64(contents)
} else {
off = uint64(binary.BigEndian.Uint32(contents))
}
contents = contents[wordSize:]
ret[name] = off
}
return ret
}
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