From 95e765b1cc43ac521bd4fd501e00774e34401449 Mon Sep 17 00:00:00 2001 From: dustin-ward Date: Thu, 18 Aug 2022 14:02:41 -0400 Subject: [PATCH] x/sys/unix: make ReadDirent available on zOS Currently ReadDirent is not available on zOS. This implementation modifies the current darwin implementation to work on zOS. Also make tests available on zOS. Fixes golang/go#54528 Fixes golang/go#54587 Change-Id: I62a09d0068ec8c5fdc849a411ce43bdf14ca3926 Reviewed-on: https://go-review.googlesource.com/c/sys/+/424778 Reviewed-by: Ian Lance Taylor TryBot-Result: Gopher Robot Reviewed-by: Joedian Reid Reviewed-by: Bill O'Farrell Run-TryBot: Ian Lance Taylor Auto-Submit: Ian Lance Taylor --- unix/dirent.go | 4 +- unix/dirent_test.go | 4 +- unix/getdirentries_test.go | 4 +- unix/syscall_zos_s390x.go | 173 ++++++++++++++++++++++++++++++++++++- unix/ztypes_zos_s390x.go | 11 ++- 5 files changed, 188 insertions(+), 8 deletions(-) diff --git a/unix/dirent.go b/unix/dirent.go index e74e5eaa3..2499f977b 100644 --- a/unix/dirent.go +++ b/unix/dirent.go @@ -2,8 +2,8 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris -// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris +//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos +// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos package unix diff --git a/unix/dirent_test.go b/unix/dirent_test.go index cbe12b0aa..1a011ddf5 100644 --- a/unix/dirent_test.go +++ b/unix/dirent_test.go @@ -2,8 +2,8 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris -// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris +//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos +// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos package unix_test diff --git a/unix/getdirentries_test.go b/unix/getdirentries_test.go index 592c0e6af..6f78e4964 100644 --- a/unix/getdirentries_test.go +++ b/unix/getdirentries_test.go @@ -2,8 +2,8 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -//go:build darwin || dragonfly || freebsd || openbsd || netbsd -// +build darwin dragonfly freebsd openbsd netbsd +//go:build darwin || dragonfly || freebsd || openbsd || netbsd || zos +// +build darwin dragonfly freebsd openbsd netbsd zos package unix_test diff --git a/unix/syscall_zos_s390x.go b/unix/syscall_zos_s390x.go index f8616f454..68b2f3e1c 100644 --- a/unix/syscall_zos_s390x.go +++ b/unix/syscall_zos_s390x.go @@ -9,8 +9,10 @@ package unix import ( "bytes" + "fmt" "runtime" "sort" + "strings" "sync" "syscall" "unsafe" @@ -55,7 +57,13 @@ func (d *Dirent) NameString() string { if d == nil { return "" } - return string(d.Name[:d.Namlen]) + s := string(d.Name[:]) + idx := strings.IndexByte(s, 0) + if idx == -1 { + return s + } else { + return s[:idx] + } } func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) { @@ -1230,6 +1238,14 @@ func Readdir(dir uintptr) (*Dirent, error) { return &ent, err } +func readdir_r(dirp uintptr, entry *direntLE, result **direntLE) (err error) { + r0, _, e1 := syscall_syscall(SYS___READDIR_R_A, dirp, uintptr(unsafe.Pointer(entry)), uintptr(unsafe.Pointer(result))) + if int64(r0) == -1 { + err = errnoErr(Errno(e1)) + } + return +} + func Closedir(dir uintptr) error { _, _, e := syscall_syscall(SYS_CLOSEDIR, dir, 0, 0) if e != 0 { @@ -1821,3 +1837,158 @@ func Unmount(name string, mtm int) (err error) { } return err } + +func fdToPath(dirfd int) (path string, err error) { + var buffer [1024]byte + // w_ctrl() + ret := runtime.CallLeFuncByPtr(runtime.XplinkLibvec+SYS_W_IOCTL<<4, + []uintptr{uintptr(dirfd), 17, 1024, uintptr(unsafe.Pointer(&buffer[0]))}) + if ret == 0 { + zb := bytes.IndexByte(buffer[:], 0) + if zb == -1 { + zb = len(buffer) + } + // __e2a_l() + runtime.CallLeFuncByPtr(runtime.XplinkLibvec+SYS___E2A_L<<4, + []uintptr{uintptr(unsafe.Pointer(&buffer[0])), uintptr(zb)}) + return string(buffer[:zb]), nil + } + // __errno() + errno := int(*(*int32)(unsafe.Pointer(runtime.CallLeFuncByPtr(runtime.XplinkLibvec+SYS___ERRNO<<4, + []uintptr{})))) + // __errno2() + errno2 := int(runtime.CallLeFuncByPtr(runtime.XplinkLibvec+SYS___ERRNO2<<4, + []uintptr{})) + // strerror_r() + ret = runtime.CallLeFuncByPtr(runtime.XplinkLibvec+SYS_STRERROR_R<<4, + []uintptr{uintptr(errno), uintptr(unsafe.Pointer(&buffer[0])), 1024}) + if ret == 0 { + zb := bytes.IndexByte(buffer[:], 0) + if zb == -1 { + zb = len(buffer) + } + return "", fmt.Errorf("%s (errno2=0x%x)", buffer[:zb], errno2) + } else { + return "", fmt.Errorf("fdToPath errno %d (errno2=0x%x)", errno, errno2) + } +} + +func direntLeToDirentUnix(dirent *direntLE, dir uintptr, path string) (Dirent, error) { + var d Dirent + + d.Ino = uint64(dirent.Ino) + offset, err := Telldir(dir) + if err != nil { + return d, err + } + + d.Off = int64(offset) + s := string(bytes.Split(dirent.Name[:], []byte{0})[0]) + copy(d.Name[:], s) + + d.Reclen = uint16(24 + len(d.NameString())) + var st Stat_t + path = path + "/" + s + err = Lstat(path, &st) + if err != nil { + return d, err + } + + d.Type = uint8(st.Mode >> 24) + return d, err +} + +func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) { + // Simulation of Getdirentries port from the Darwin implementation. + // COMMENTS FROM DARWIN: + // It's not the full required semantics, but should handle the case + // of calling Getdirentries or ReadDirent repeatedly. + // It won't handle assigning the results of lseek to *basep, or handle + // the directory being edited underfoot. + + skip, err := Seek(fd, 0, 1 /* SEEK_CUR */) + if err != nil { + return 0, err + } + + // Get path from fd to avoid unavailable call (fdopendir) + path, err := fdToPath(fd) + if err != nil { + return 0, err + } + d, err := Opendir(path) + if err != nil { + return 0, err + } + defer Closedir(d) + + var cnt int64 + for { + var entryLE direntLE + var entrypLE *direntLE + e := readdir_r(d, &entryLE, &entrypLE) + if e != nil { + return n, e + } + if entrypLE == nil { + break + } + if skip > 0 { + skip-- + cnt++ + continue + } + + // Dirent on zos has a different structure + entry, e := direntLeToDirentUnix(&entryLE, d, path) + if e != nil { + return n, e + } + + reclen := int(entry.Reclen) + if reclen > len(buf) { + // Not enough room. Return for now. + // The counter will let us know where we should start up again. + // Note: this strategy for suspending in the middle and + // restarting is O(n^2) in the length of the directory. Oh well. + break + } + + // Copy entry into return buffer. + s := unsafe.Slice((*byte)(unsafe.Pointer(&entry)), reclen) + copy(buf, s) + + buf = buf[reclen:] + n += reclen + cnt++ + } + // Set the seek offset of the input fd to record + // how many files we've already returned. + _, err = Seek(fd, cnt, 0 /* SEEK_SET */) + if err != nil { + return n, err + } + + return n, nil +} + +func ReadDirent(fd int, buf []byte) (n int, err error) { + var base = (*uintptr)(unsafe.Pointer(new(uint64))) + return Getdirentries(fd, buf, base) +} + +func direntIno(buf []byte) (uint64, bool) { + return readInt(buf, unsafe.Offsetof(Dirent{}.Ino), unsafe.Sizeof(Dirent{}.Ino)) +} + +func direntReclen(buf []byte) (uint64, bool) { + return readInt(buf, unsafe.Offsetof(Dirent{}.Reclen), unsafe.Sizeof(Dirent{}.Reclen)) +} + +func direntNamlen(buf []byte) (uint64, bool) { + reclen, ok := direntReclen(buf) + if !ok { + return 0, false + } + return reclen - uint64(unsafe.Offsetof(Dirent{}.Name)), true +} diff --git a/unix/ztypes_zos_s390x.go b/unix/ztypes_zos_s390x.go index 4ab638cb9..aec1efcb3 100644 --- a/unix/ztypes_zos_s390x.go +++ b/unix/ztypes_zos_s390x.go @@ -339,7 +339,7 @@ type Statfs_t struct { Flags uint64 } -type Dirent struct { +type direntLE struct { Reclen uint16 Namlen uint16 Ino uint32 @@ -347,6 +347,15 @@ type Dirent struct { Name [256]byte } +type Dirent struct { + Ino uint64 + Off int64 + Reclen uint16 + Type uint8 + Name [256]uint8 + _ [5]byte +} + type FdSet struct { Bits [64]int32 }