delve/pkg/proc/native/ptrace_linux_386.go
chainhelen f3a191cd73
pkg/proc,service: support linux/386 (#1884)
Implement debugging function for 386 on linux with reference to AMD64.
There are a few remaining problems that need to be solved in another time.

1. The stacktrace of cgo are not exactly as expected.
2. Not implement `core` for now.
3. Not implement `call` for now. Can't not find `runtime·debugCallV1` or
   similar function in $GOROOT/src/runtime/asm_386.s.

Update #20
2020-03-10 09:34:40 -07:00

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package native
import "C"
import (
"fmt"
"syscall"
"unsafe"
sys "golang.org/x/sys/unix"
"github.com/go-delve/delve/pkg/proc/linutil"
)
// PtraceGetRegset returns floating point registers of the specified thread
// using PTRACE.
// See i386_linux_fetch_inferior_registers in gdb/i386-linux-nat.c.html
// and i386_supply_xsave in gdb/i386-tdep.c.html
// and Section 13.1 (and following) of Intel® 64 and IA-32 Architectures Software Developers Manual, Volume 1: Basic Architecture
func PtraceGetRegset(tid int) (regset linutil.I386Xstate, err error) {
_, _, err = syscall.Syscall6(syscall.SYS_PTRACE, sys.PTRACE_GETFPREGS, uintptr(tid), uintptr(0), uintptr(unsafe.Pointer(&regset.I386PtraceFpRegs)), 0, 0)
if err == syscall.Errno(0) || err == syscall.ENODEV {
// ignore ENODEV, it just means this CPU doesn't have X87 registers (??)
err = nil
}
var xstateargs [_X86_XSTATE_MAX_SIZE]byte
iov := sys.Iovec{Base: &xstateargs[0], Len: _X86_XSTATE_MAX_SIZE}
_, _, err = syscall.Syscall6(syscall.SYS_PTRACE, sys.PTRACE_GETREGSET, uintptr(tid), _NT_X86_XSTATE, uintptr(unsafe.Pointer(&iov)), 0, 0)
if err != syscall.Errno(0) {
if err == syscall.ENODEV || err == syscall.EIO {
// ignore ENODEV, it just means this CPU or kernel doesn't support XSTATE, see https://github.com/go-delve/delve/issues/1022
// also ignore EIO, it means that we are running on an old kernel (pre 2.6.34) and PTRACE_GETREGSET is not implemented
err = nil
}
return
} else {
err = nil
}
regset.Xsave = xstateargs[:iov.Len]
err = linutil.I386XstateRead(regset.Xsave, false, &regset)
return
}
// PtraceGetTls return the addr of tls by PTRACE_GET_THREAD_AREA for specify thread.
// See http://man7.org/linux/man-pages/man2/ptrace.2.html for detail about PTRACE_GET_THREAD_AREA.
// struct user_desc at https://golang.org/src/runtime/sys_linux_386.s
// type UserDesc struct {
// EntryNumber uint32
// BaseAddr uint32
// Limit uint32
// Flag uint32
// }
func PtraceGetTls(gs int32, tid int) (uint32, error) {
ud := [4]uint32{}
// Gs usually is 0x33
_, _, err := syscall.Syscall6(syscall.SYS_PTRACE, sys.PTRACE_GET_THREAD_AREA, uintptr(tid), uintptr(gs>>3), uintptr(unsafe.Pointer(&ud)), 0, 0)
if err == syscall.ENODEV || err == syscall.EIO {
return 0, fmt.Errorf("%s", err)
}
return uint32(ud[1]), nil
}
// ProcessVmRead calls process_vm_readv
func ProcessVmRead(tid int, addr uintptr, data []byte) (int, error) {
len_iov := uint32(len(data))
local_iov := sys.Iovec{Base: &data[0], Len: len_iov}
remote_iov := sys.Iovec{Base: (*byte)(unsafe.Pointer(addr)), Len: len_iov}
p_local := uintptr(unsafe.Pointer(&local_iov))
p_remote := uintptr(unsafe.Pointer(&remote_iov))
n, _, err := syscall.Syscall6(sys.SYS_PROCESS_VM_READV, uintptr(tid), p_local, 1, p_remote, 1, 0)
if err != syscall.Errno(0) {
return 0, err
}
return int(n), nil
}
// ProcessVmWrite calls process_vm_writev
func ProcessVmWrite(tid int, addr uintptr, data []byte) (int, error) {
len_iov := uint32(len(data))
local_iov := sys.Iovec{Base: &data[0], Len: len_iov}
remote_iov := sys.Iovec{Base: (*byte)(unsafe.Pointer(addr)), Len: len_iov}
p_local := uintptr(unsafe.Pointer(&local_iov))
p_remote := uintptr(unsafe.Pointer(&remote_iov))
n, _, err := syscall.Syscall6(sys.SYS_PROCESS_VM_WRITEV, uintptr(tid), p_local, 1, p_remote, 1, 0)
if err != syscall.Errno(0) {
return 0, err
}
return int(n), nil
}