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|
//go:build !remote
package emulation
import (
"debug/elf"
"encoding/binary"
"fmt"
"sync"
"github.com/sirupsen/logrus"
)
type elfPlatform struct {
platform string
osabi []elf.OSABI
class elf.Class
data elf.Data
alsoNone bool // also try with data=none,version=0
machine elf.Machine
flags []uint32
}
var (
// knownELFPlatformHeaders is a mapping from target platform names and
// plausible headers for the binaries built for those platforms. Call
// getKnownELFPlatformHeaders() instead of reading this map directly.
knownELFPlatformHeaders = make(map[string][][]byte)
knownELFPlatformHeadersOnce sync.Once
// knownELFPlatforms is a table of target platforms that we built a
// trivial program for, and the other fields are filled in based on
// what we got when we ran eu-readelf -h against the results.
knownELFPlatforms = []elfPlatform{
{
platform: "linux/386",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS32,
data: elf.ELFDATA2LSB,
alsoNone: true,
machine: elf.EM_386,
},
{
platform: "linux/amd64",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2LSB,
alsoNone: true,
machine: elf.EM_X86_64,
},
{
platform: "linux/arm",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS32,
data: elf.ELFDATA2LSB,
machine: elf.EM_ARM,
},
{
platform: "linux/arm64",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2LSB,
machine: elf.EM_AARCH64,
},
{
platform: "linux/arm64be",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2MSB,
machine: elf.EM_AARCH64,
},
{
platform: "linux/loong64",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2LSB,
machine: elf.EM_LOONGARCH,
},
{
platform: "linux/mips",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS32,
data: elf.ELFDATA2MSB,
machine: elf.EM_MIPS,
flags: []uint32{0, 2}, // elf.EF_MIPS_PIC set, or not
},
{
platform: "linux/mipsle",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS32,
data: elf.ELFDATA2LSB,
machine: elf.EM_MIPS_RS3_LE,
flags: []uint32{0, 2}, // elf.EF_MIPS_PIC set, or not
},
{
platform: "linux/mips64",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2MSB,
machine: elf.EM_MIPS,
flags: []uint32{0, 2}, // elf.EF_MIPS_PIC set, or not
},
{
platform: "linux/mips64le",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2LSB,
machine: elf.EM_MIPS_RS3_LE,
flags: []uint32{0, 2}, // elf.EF_MIPS_PIC set, or not
},
{
platform: "linux/ppc",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS32,
data: elf.ELFDATA2MSB,
machine: elf.EM_PPC,
},
{
platform: "linux/ppc64",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2MSB,
machine: elf.EM_PPC64,
},
{
platform: "linux/ppc64le",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2LSB,
machine: elf.EM_PPC64,
},
{
platform: "linux/riscv32",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS32,
data: elf.ELFDATA2LSB,
machine: elf.EM_RISCV,
},
{
platform: "linux/riscv64",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2LSB,
machine: elf.EM_RISCV,
},
{
platform: "linux/s390x",
osabi: []elf.OSABI{elf.ELFOSABI_NONE, elf.ELFOSABI_LINUX},
class: elf.ELFCLASS64,
data: elf.ELFDATA2MSB,
machine: elf.EM_S390,
},
}
)
// header generates an approximation of what the initial N bytes of a binary
// built for a given target looks like
func (e *elfPlatform) header() ([][]byte, error) {
var headers [][]byte
osabi := e.osabi
if len(osabi) == 0 {
osabi = []elf.OSABI{elf.ELFOSABI_NONE}
}
for i := range osabi {
flags := e.flags
if len(flags) == 0 {
flags = []uint32{0}
}
for f := range flags {
var endian binary.ByteOrder
var entrySize, phoffSize, shoffSize int
header := make([]byte, 40)
copy(header, elf.ELFMAG)
switch e.class {
case elf.ELFCLASS32:
entrySize, phoffSize, shoffSize = 2, 2, 2
case elf.ELFCLASS64:
entrySize, phoffSize, shoffSize = 4, 4, 4
}
switch e.data {
case elf.ELFDATA2LSB:
endian = binary.LittleEndian
case elf.ELFDATA2MSB:
endian = binary.BigEndian
default:
return nil, fmt.Errorf("internal error in entry for %q", e.platform)
}
header[elf.EI_OSABI] = byte(osabi[i])
header[elf.EI_CLASS] = byte(e.class)
header[elf.EI_DATA] = byte(e.data)
header[elf.EI_VERSION] = byte(elf.EV_CURRENT)
header[elf.EI_ABIVERSION] = 0
endian.PutUint16(header[16:], uint16(elf.ET_EXEC))
endian.PutUint16(header[18:], uint16(e.machine))
endian.PutUint32(header[20:], uint32(elf.EV_CURRENT))
endian.PutUint32(header[24+entrySize+phoffSize+shoffSize:], flags[f])
headers = append(headers, append([]byte{}, header...))
if e.alsoNone {
header[elf.EI_DATA] = byte(elf.ELFDATANONE)
header[elf.EI_VERSION] = byte(elf.EV_NONE)
endian.PutUint32(header[20:], uint32(elf.EV_NONE))
headers = append(headers, append([]byte{}, header...))
}
}
}
return headers, nil
}
func getKnownELFPlatformHeaders() map[string][][]byte {
knownELFPlatformHeadersOnce.Do(func() {
for _, p := range knownELFPlatforms {
headerList, err := p.header()
if err != nil {
logrus.Errorf("generating headers for %q: %v\n", p.platform, err)
continue
}
knownELFPlatformHeaders[p.platform] = headerList
}
})
return knownELFPlatformHeaders
}
|
