os: reset dirinfo when seeking on Darwin
The first Readdirnames calls opendir and caches the result.
The behavior of that cached opendir result isn't specified on a seek
of the underlying fd. Free the opendir result on a seek so that
we'll allocate a new one the next time around.
Also fix wasm behavior in this regard, so that a seek to the
file start resets the Readdirnames position, regardless of platform.
p.s. I hate the Readdirnames API.
Fixes #35767.
Change-Id: Ieffb61b3c5cdd42591f69ab13f932003966f2297
Reviewed-on: https://go-review.googlesource.com/c/go/+/209961
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/os/dir_darwin.go b/src/os/dir_darwin.go
index 2f9ba78..a274dd1 100644
--- a/src/os/dir_darwin.go
+++ b/src/os/dir_darwin.go
@@ -24,6 +24,16 @@
d.dir = 0
}
+func (f *File) seekInvalidate() {
+ if f.dirinfo == nil {
+ return
+ }
+ // Free cached dirinfo, so we allocate a new one if we
+ // access this file as a directory again. See #35767.
+ f.dirinfo.close()
+ f.dirinfo = nil
+}
+
func (f *File) readdirnames(n int) (names []string, err error) {
if f.dirinfo == nil {
dir, call, errno := f.pfd.OpenDir()
diff --git a/src/os/dir_unix.go b/src/os/dir_unix.go
index e0c4989..2856a2d 100644
--- a/src/os/dir_unix.go
+++ b/src/os/dir_unix.go
@@ -26,6 +26,8 @@
func (d *dirInfo) close() {}
+func (f *File) seekInvalidate() {}
+
func (f *File) readdirnames(n int) (names []string, err error) {
// If this file has no dirinfo, create one.
if f.dirinfo == nil {
diff --git a/src/os/file_unix.go b/src/os/file_unix.go
index 31c43eb..6945937 100644
--- a/src/os/file_unix.go
+++ b/src/os/file_unix.go
@@ -295,6 +295,7 @@
// relative to the current offset, and 2 means relative to the end.
// It returns the new offset and an error, if any.
func (f *File) seek(offset int64, whence int) (ret int64, err error) {
+ f.seekInvalidate()
ret, err = f.pfd.Seek(offset, whence)
runtime.KeepAlive(f)
return ret, err
diff --git a/src/syscall/fs_js.go b/src/syscall/fs_js.go
index f7079e9..16d9f58 100644
--- a/src/syscall/fs_js.go
+++ b/src/syscall/fs_js.go
@@ -34,6 +34,7 @@
type jsFile struct {
path string
entries []string
+ dirIdx int // entries[:dirIdx] have already been returned in ReadDirent
pos int64
seeked bool
}
@@ -141,8 +142,8 @@
}
n := 0
- for len(f.entries) > 0 {
- entry := f.entries[0]
+ for f.dirIdx < len(f.entries) {
+ entry := f.entries[f.dirIdx]
l := 2 + len(entry)
if l > len(buf) {
break
@@ -152,7 +153,7 @@
copy(buf[2:], entry)
buf = buf[l:]
n += l
- f.entries = f.entries[1:]
+ f.dirIdx++
}
return n, nil
@@ -470,6 +471,7 @@
}
f.seeked = true
+ f.dirIdx = 0 // Reset directory read position. See issue 35767.
f.pos = newPos
return newPos, nil
}
diff --git a/test/fixedbugs/issue35767.go b/test/fixedbugs/issue35767.go
new file mode 100644
index 0000000..b930faa
--- /dev/null
+++ b/test/fixedbugs/issue35767.go
@@ -0,0 +1,51 @@
+// run
+
+// Copyright 2019 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.
+
+package main
+
+import (
+ "log"
+ "os"
+)
+
+func main() {
+ wd, err := os.Getwd()
+ if err != nil {
+ log.Fatal(err)
+ }
+ f, err := os.Open(wd)
+ if err != nil {
+ log.Fatal(err)
+ }
+ dirnames1, err := f.Readdirnames(0)
+ if err != nil {
+ log.Fatal(err)
+ }
+
+ ret, err := f.Seek(0, 0)
+ if err != nil {
+ log.Fatal(err)
+ }
+ if ret != 0 {
+ log.Fatalf("seek result not zero: %d", ret)
+ }
+
+ dirnames2, err := f.Readdirnames(0)
+ if err != nil {
+ log.Fatal(err)
+ return
+ }
+
+ if len(dirnames1) != len(dirnames2) {
+ log.Fatalf("listings have different lengths: %d and %d\n", len(dirnames1), len(dirnames2))
+ }
+ for i, n1 := range dirnames1 {
+ n2 := dirnames2[i]
+ if n1 != n2 {
+ log.Fatalf("different name i=%d n1=%s n2=%s\n", i, n1, n2)
+ }
+ }
+}
