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Merge pull request #1751 from restic/fix-archiver

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archiver: Use lstat before open/fstat
This commit is contained in:
Alexander Neumann 2018-05-01 23:15:32 +02:00
commit 9d6890a236
1 changed files with 40 additions and 36 deletions
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76
internal/archiver/archiver.go
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@ -7,7 +7,6 @@ import (
"path"
"runtime"
"sort"
"syscall"
"time"
"github.com/restic/restic/internal/debug"
@ -331,36 +330,19 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
fn.absTarget = abstarget
var fi os.FileInfo
var errFI error
file, errOpen := arch.FS.OpenFile(target, fs.O_RDONLY|fs.O_NOFOLLOW|fs.O_NONBLOCK, 0)
if errOpen == nil {
fi, errFI = file.Stat()
}
fi, err := arch.FS.Lstat(target)
if !arch.Select(abstarget, fi) {
debug.Log("%v is excluded", target)
if file != nil {
_ = file.Close()
}
return FutureNode{}, true, nil
}
if errOpen != nil {
debug.Log(" open error %#v", errOpen)
// test if the open failed because target is a symbolic link or a socket
if e, ok := errOpen.(*os.PathError); ok && (e.Err == syscall.ELOOP || e.Err == syscall.ENXIO) {
// in this case, redo the stat and carry on
fi, errFI = arch.FS.Lstat(target)
} else {
return FutureNode{}, false, errors.Wrap(errOpen, "OpenFile")
if err != nil {
debug.Log("lstat() for %v returned error: %v", target, err)
err = arch.error(abstarget, fi, err)
if err != nil {
return FutureNode{}, false, errors.Wrap(err, "Lstat")
}
}
if errFI != nil {
_ = file.Close()
return FutureNode{}, false, errors.Wrap(errFI, "Stat")
return FutureNode{}, true, nil
}
switch {
@ -368,6 +350,39 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
debug.Log(" %v regular file", target)
start := time.Now()
// reopen file and do an fstat() on the open file to check it is still
// a file (and has not been exchanged for e.g. a symlink)
file, err := arch.FS.OpenFile(target, fs.O_RDONLY|fs.O_NOFOLLOW|fs.O_NONBLOCK, 0)
if err != nil {
debug.Log("Openfile() for %v returned error: %v", target, err)
err = arch.error(abstarget, fi, err)
if err != nil {
return FutureNode{}, false, errors.Wrap(err, "Lstat")
}
return FutureNode{}, true, nil
}
fi, err = file.Stat()
if err != nil {
debug.Log("stat() on opened file %v returned error: %v", target, err)
_ = file.Close()
err = arch.error(abstarget, fi, err)
if err != nil {
return FutureNode{}, false, errors.Wrap(err, "Lstat")
}
return FutureNode{}, true, nil
}
// make sure it's still a file
if !fs.IsRegularFile(fi) {
err = errors.Errorf("file %v changed type, refusing to archive")
err = arch.error(abstarget, fi, err)
if err != nil {
return FutureNode{}, false, err
}
return FutureNode{}, true, nil
}
// use previous node if the file hasn't changed
if previous != nil && !fileChanged(fi, previous) {
debug.Log("%v hasn't changed, returning old node", target)
@ -386,8 +401,6 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
arch.CompleteItem(snPath, previous, node, stats, time.Since(start))
})
file = nil
case fi.IsDir():
debug.Log(" %v dir", target)
@ -400,7 +413,6 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
if err == nil {
arch.CompleteItem(snItem, previous, fn.node, fn.stats, time.Since(start))
} else {
_ = file.Close()
return FutureNode{}, false, err
}
@ -413,18 +425,10 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
fn.node, err = arch.nodeFromFileInfo(target, fi)
if err != nil {
_ = file.Close()
return FutureNode{}, false, err
}
}
if file != nil {
err = file.Close()
if err != nil {
return fn, false, errors.Wrap(err, "Close")
}
}
debug.Log("return after %.3f", time.Since(start).Seconds())
return fn, false, nil