cmd/pprof: add readline support similar to upstream

The upstream pprof implements the readline feature using
the github.com/chzyer/readline package in its pprof.go main.

It would be ideal to use the same readline support package as
the upstream for better user experience and code maintenance.
However, bringing in third-party packages requires more work
than I envisioned (e.g. clean up the vendored code to meet the
expected standard - iow don't break builders).

As a result, this change implements the similar feature
for the pprof command included in the go distribution
(cmd/pprof/pprof.go) using golang.org/x/crypto/ssh/terminal
for now.

Auto-completion is not yet supported (same in the upstream).

The feature is enabled only in linux, windows, darwin, and
only when terminal support is available.

This change brings in new vendored packages,
golang.org/x/crypto/ssh/terminal and
golang.org/x/sys/{unix,windows}.

For #14041

Change-Id: If4a790796acf2ab20f7e81268b9d9354c5a5cd2b
Reviewed-on: https://go-review.googlesource.com/112436
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 255 insertions, 0 deletions

diff --git a/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux_arm.go b/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux_arm.go
new file mode 100644
index 0000000000..c59f8588f1
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux_arm.go
@@ -0,0 +1,255 @@
+// 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 arm,linux
+
+package unix
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: int32(sec), Nsec: int32(nsec)}
+}
+
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: int32(sec), Usec: int32(usec)}
+}
+
+func Pipe(p []int) (err error) {
+	if len(p) != 2 {
+		return EINVAL
+	}
+	var pp [2]_C_int
+	err = pipe2(&pp, 0)
+	p[0] = int(pp[0])
+	p[1] = int(pp[1])
+	return
+}
+
+//sysnb pipe2(p *[2]_C_int, flags int) (err error)
+
+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
+}
+
+// Underlying system call writes to newoffset via pointer.
+// Implemented in assembly to avoid allocation.
+func seek(fd int, offset int64, whence int) (newoffset int64, err syscall.Errno)
+
+func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
+	newoffset, errno := seek(fd, offset, whence)
+	if errno != 0 {
+		return 0, errno
+	}
+	return newoffset, nil
+}
+
+//sys	accept(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (fd int, err error)
+//sys	accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error)
+//sys	bind(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
+//sys	connect(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
+//sysnb	getgroups(n int, list *_Gid_t) (nn int, err error) = SYS_GETGROUPS32
+//sysnb	setgroups(n int, list *_Gid_t) (err error) = SYS_SETGROUPS32
+//sys	getsockopt(s int, level int, name int, val unsafe.Pointer, vallen *_Socklen) (err error)
+//sys	setsockopt(s int, level int, name int, val unsafe.Pointer, vallen uintptr) (err error)
+//sysnb	socket(domain int, typ int, proto int) (fd int, err error)
+//sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
+//sysnb	getsockname(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
+//sys	recvfrom(fd int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, err error)
+//sys	sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
+//sysnb	socketpair(domain int, typ int, flags int, fd *[2]int32) (err error)
+//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error)
+//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error)
+
+// 64-bit file system and 32-bit uid calls
+// (16-bit uid calls are not always supported in newer kernels)
+//sys	Dup2(oldfd int, newfd int) (err error)
+//sys	Fchown(fd int, uid int, gid int) (err error) = SYS_FCHOWN32
+//sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
+//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
+//sysnb	Getegid() (egid int) = SYS_GETEGID32
+//sysnb	Geteuid() (euid int) = SYS_GETEUID32
+//sysnb	Getgid() (gid int) = SYS_GETGID32
+//sysnb	Getuid() (uid int) = SYS_GETUID32
+//sysnb	InotifyInit() (fd int, err error)
+//sys	Lchown(path string, uid int, gid int) (err error) = SYS_LCHOWN32
+//sys	Listen(s int, n int) (err error)
+//sys	Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
+//sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) = SYS_SENDFILE64
+//sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) = SYS__NEWSELECT
+//sys	Setfsgid(gid int) (err error) = SYS_SETFSGID32
+//sys	Setfsuid(uid int) (err error) = SYS_SETFSUID32
+//sysnb	Setregid(rgid int, egid int) (err error) = SYS_SETREGID32
+//sysnb	Setresgid(rgid int, egid int, sgid int) (err error) = SYS_SETRESGID32
+//sysnb	Setresuid(ruid int, euid int, suid int) (err error) = SYS_SETRESUID32
+//sysnb	Setreuid(ruid int, euid int) (err error) = SYS_SETREUID32
+//sys	Shutdown(fd int, how int) (err error)
+//sys	Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error)
+//sys	Stat(path string, stat *Stat_t) (err error) = SYS_STAT64
+
+// Vsyscalls on amd64.
+//sysnb	Gettimeofday(tv *Timeval) (err error)
+//sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
+//sys	Pause() (err error)
+
+func Time(t *Time_t) (Time_t, error) {
+	var tv Timeval
+	err := Gettimeofday(&tv)
+	if err != nil {
+		return 0, err
+	}
+	if t != nil {
+		*t = Time_t(tv.Sec)
+	}
+	return Time_t(tv.Sec), nil
+}
+
+func Utime(path string, buf *Utimbuf) error {
+	tv := []Timeval{
+		{Sec: buf.Actime},
+		{Sec: buf.Modtime},
+	}
+	return Utimes(path, tv)
+}
+
+//sys   Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
+//sys   Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
+//sys	Truncate(path string, length int64) (err error) = SYS_TRUNCATE64
+//sys	Ftruncate(fd int, length int64) (err error) = SYS_FTRUNCATE64
+
+func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
+	_, _, e1 := Syscall6(SYS_ARM_FADVISE64_64, uintptr(fd), uintptr(advice), uintptr(offset), uintptr(offset>>32), uintptr(length), uintptr(length>>32))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+//sys	mmap2(addr uintptr, length uintptr, prot int, flags int, fd int, pageOffset uintptr) (xaddr uintptr, err error)
+
+func Fstatfs(fd int, buf *Statfs_t) (err error) {
+	_, _, e := Syscall(SYS_FSTATFS64, uintptr(fd), unsafe.Sizeof(*buf), uintptr(unsafe.Pointer(buf)))
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func Statfs(path string, buf *Statfs_t) (err error) {
+	pathp, err := BytePtrFromString(path)
+	if err != nil {
+		return err
+	}
+	_, _, e := Syscall(SYS_STATFS64, uintptr(unsafe.Pointer(pathp)), unsafe.Sizeof(*buf), uintptr(unsafe.Pointer(buf)))
+	if e != 0 {
+		err = e
+	}
+	return
+}
+
+func mmap(addr uintptr, length uintptr, prot int, flags int, fd int, offset int64) (xaddr uintptr, err error) {
+	page := uintptr(offset / 4096)
+	if offset != int64(page)*4096 {
+		return 0, EINVAL
+	}
+	return mmap2(addr, length, prot, flags, fd, page)
+}
+
+type rlimit32 struct {
+	Cur uint32
+	Max uint32
+}
+
+//sysnb getrlimit(resource int, rlim *rlimit32) (err error) = SYS_UGETRLIMIT
+
+const rlimInf32 = ^uint32(0)
+const rlimInf64 = ^uint64(0)
+
+func Getrlimit(resource int, rlim *Rlimit) (err error) {
+	err = prlimit(0, resource, nil, rlim)
+	if err != ENOSYS {
+		return err
+	}
+
+	rl := rlimit32{}
+	err = getrlimit(resource, &rl)
+	if err != nil {
+		return
+	}
+
+	if rl.Cur == rlimInf32 {
+		rlim.Cur = rlimInf64
+	} else {
+		rlim.Cur = uint64(rl.Cur)
+	}
+
+	if rl.Max == rlimInf32 {
+		rlim.Max = rlimInf64
+	} else {
+		rlim.Max = uint64(rl.Max)
+	}
+	return
+}
+
+//sysnb setrlimit(resource int, rlim *rlimit32) (err error) = SYS_SETRLIMIT
+
+func Setrlimit(resource int, rlim *Rlimit) (err error) {
+	err = prlimit(0, resource, rlim, nil)
+	if err != ENOSYS {
+		return err
+	}
+
+	rl := rlimit32{}
+	if rlim.Cur == rlimInf64 {
+		rl.Cur = rlimInf32
+	} else if rlim.Cur < uint64(rlimInf32) {
+		rl.Cur = uint32(rlim.Cur)
+	} else {
+		return EINVAL
+	}
+	if rlim.Max == rlimInf64 {
+		rl.Max = rlimInf32
+	} else if rlim.Max < uint64(rlimInf32) {
+		rl.Max = uint32(rlim.Max)
+	} else {
+		return EINVAL
+	}
+
+	return setrlimit(resource, &rl)
+}
+
+func (r *PtraceRegs) PC() uint64 { return uint64(r.Uregs[15]) }
+
+func (r *PtraceRegs) SetPC(pc uint64) { r.Uregs[15] = uint32(pc) }
+
+func (iov *Iovec) SetLen(length int) {
+	iov.Len = uint32(length)
+}
+
+func (msghdr *Msghdr) SetControllen(length int) {
+	msghdr.Controllen = uint32(length)
+}
+
+func (cmsg *Cmsghdr) SetLen(length int) {
+	cmsg.Len = uint32(length)
+}
+
+//sys	poll(fds *PollFd, nfds int, timeout int) (n int, err error)
+
+func Poll(fds []PollFd, timeout int) (n int, err error) {
+	if len(fds) == 0 {
+		return poll(nil, 0, timeout)
+	}
+	return poll(&fds[0], len(fds), timeout)
+}