gcc/libgo/go/syscall/libcall_glibc.go
Paul E. Murphy c560591408 libgo: fix ptrace syscall hooks into glibc
ptrace is actually declared as a variadic function.  On ppc64le
the ABI requires to the caller to allocate space for the parameters
and allows the caller to modify them.

On ppc64le, depending on how and what version of GCC is used,
it will save to parameter save area.  This happened to clobber
a saved LR, and caused syscall.TestExecPtrace to fail with a timeout
when the tracee segfaults, and waits for the parent process to inspect.

Wrap this function to avoid directly calling glibc's ptrace from go.

Fixes golang/go#36698
Fixes go/92567

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/254755
2020-09-17 12:14:09 -07:00

136 lines
4.0 KiB
Go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build hurd linux
// glibc library calls.
package syscall
import (
"internal/race"
"unsafe"
)
//sys Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error)
//__go_openat(dirfd _C_int, path *byte, flags _C_int, mode Mode_t) _C_int
//sys futimesat(dirfd int, path *byte, times *[2]Timeval) (err error)
//futimesat(dirfd _C_int, path *byte, times *[2]Timeval) _C_int
func Futimesat(dirfd int, path string, tv []Timeval) (err error) {
if len(tv) != 2 {
return EINVAL
}
return futimesat(dirfd, StringBytePtr(path), (*[2]Timeval)(unsafe.Pointer(&tv[0])))
}
func Futimes(fd int, tv []Timeval) (err error) {
// Believe it or not, this is the best we can do on GNU/Linux
// (and is what glibc does).
return Utimes("/proc/self/fd/"+itoa(fd), tv)
}
//sys ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
//__go_ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long
//sys accept4(fd int, sa *RawSockaddrAny, len *Socklen_t, flags int) (nfd int, err error)
//accept4(fd _C_int, sa *RawSockaddrAny, len *Socklen_t, flags _C_int) _C_int
func Accept4(fd int, flags int) (nfd int, sa Sockaddr, err error) {
var rsa RawSockaddrAny
var len Socklen_t = SizeofSockaddrAny
nfd, err = accept4(fd, &rsa, &len, flags)
if err != nil {
return -1, nil, err
}
sa, err = anyToSockaddr(&rsa)
if err != nil {
Close(nfd)
return -1, nil, err
}
return nfd, sa, nil
}
//sysnb Dup3(oldfd int, newfd int, flags int) (err error)
//dup3(oldfd _C_int, newfd _C_int, flags _C_int) _C_int
//sys Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
//faccessat(dirfd _C_int, pathname *byte, mode _C_int, flags _C_int) _C_int
//sys Fallocate(fd int, mode uint32, off int64, len int64) (err error)
//fallocate(fd _C_int, mode _C_int, offset Offset_t, len Offset_t) _C_int
//sys Fchmodat(dirfd int, path string, mode uint32, flags int) (err error)
//fchmodat(dirfd _C_int, pathname *byte, mode Mode_t, flags _C_int) _C_int
//sys Fchownat(dirfd int, path string, uid int, gid int, flags int) (err error)
//fchownat(dirfd _C_int, path *byte, owner Uid_t, group Gid_t, flags _C_int) _C_int
//sys Flock(fd int, how int) (err error)
//flock(fd _C_int, how _C_int) _C_int
func Getdents(fd int, buf []byte) (n int, err error) {
var p *byte
if len(buf) > 0 {
p = &buf[0]
} else {
p = (*byte)(unsafe.Pointer(&_zero))
}
s := SYS_GETDENTS64
if s == 0 {
s = SYS_GETDENTS
}
r1, _, errno := Syscall(uintptr(s), uintptr(fd), uintptr(unsafe.Pointer(p)), uintptr(len(buf)))
n = int(r1)
if n < 0 {
err = errno
}
return
}
func ReadDirent(fd int, buf []byte) (n int, err error) {
return Getdents(fd, buf)
}
//sys Mkdirat(dirfd int, path string, mode uint32) (err error)
//mkdirat(dirfd _C_int, path *byte, mode Mode_t) _C_int
//sys Mknodat(dirfd int, path string, mode uint32, dev int) (err error)
//mknodat(dirfd _C_int, path *byte, mode Mode_t, dev _dev_t) _C_int
//sysnb pipe2(p *[2]_C_int, flags int) (err error)
//pipe2(p *[2]_C_int, flags _C_int) _C_int
func Pipe2(p []int, flags int) (err error) {
if len(p) != 2 {
return EINVAL
}
var pp [2]_C_int
err = pipe2(&pp, flags)
p[0] = int(pp[0])
p[1] = int(pp[1])
return
}
//sys sendfile(outfd int, infd int, offset *Offset_t, count int) (written int, err error)
//sendfile64(outfd _C_int, infd _C_int, offset *Offset_t, count Size_t) Ssize_t
func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
if race.Enabled {
race.ReleaseMerge(unsafe.Pointer(&ioSync))
}
var soff Offset_t
var psoff *Offset_t
if offset != nil {
soff = Offset_t(*offset)
psoff = &soff
}
written, err = sendfile(outfd, infd, psoff, count)
if offset != nil {
*offset = int64(soff)
}
return
}
//sys SyncFileRange(fd int, off int64, n int64, flags int) (err error)
//sync_file_range(fd _C_int, off Offset_t, n Offset_t, flags _C_uint) _C_int