github.com/pkg/sftp@v1.13.6/attrs.go (about)

     1  package sftp
     2  
     3  // ssh_FXP_ATTRS support
     4  // see https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt#section-5
     5  
     6  import (
     7  	"os"
     8  	"time"
     9  )
    10  
    11  const (
    12  	sshFileXferAttrSize        = 0x00000001
    13  	sshFileXferAttrUIDGID      = 0x00000002
    14  	sshFileXferAttrPermissions = 0x00000004
    15  	sshFileXferAttrACmodTime   = 0x00000008
    16  	sshFileXferAttrExtended    = 0x80000000
    17  
    18  	sshFileXferAttrAll = sshFileXferAttrSize | sshFileXferAttrUIDGID | sshFileXferAttrPermissions |
    19  		sshFileXferAttrACmodTime | sshFileXferAttrExtended
    20  )
    21  
    22  // fileInfo is an artificial type designed to satisfy os.FileInfo.
    23  type fileInfo struct {
    24  	name string
    25  	stat *FileStat
    26  }
    27  
    28  // Name returns the base name of the file.
    29  func (fi *fileInfo) Name() string { return fi.name }
    30  
    31  // Size returns the length in bytes for regular files; system-dependent for others.
    32  func (fi *fileInfo) Size() int64 { return int64(fi.stat.Size) }
    33  
    34  // Mode returns file mode bits.
    35  func (fi *fileInfo) Mode() os.FileMode { return toFileMode(fi.stat.Mode) }
    36  
    37  // ModTime returns the last modification time of the file.
    38  func (fi *fileInfo) ModTime() time.Time { return time.Unix(int64(fi.stat.Mtime), 0) }
    39  
    40  // IsDir returns true if the file is a directory.
    41  func (fi *fileInfo) IsDir() bool { return fi.Mode().IsDir() }
    42  
    43  func (fi *fileInfo) Sys() interface{} { return fi.stat }
    44  
    45  // FileStat holds the original unmarshalled values from a call to READDIR or
    46  // *STAT. It is exported for the purposes of accessing the raw values via
    47  // os.FileInfo.Sys(). It is also used server side to store the unmarshalled
    48  // values for SetStat.
    49  type FileStat struct {
    50  	Size     uint64
    51  	Mode     uint32
    52  	Mtime    uint32
    53  	Atime    uint32
    54  	UID      uint32
    55  	GID      uint32
    56  	Extended []StatExtended
    57  }
    58  
    59  // StatExtended contains additional, extended information for a FileStat.
    60  type StatExtended struct {
    61  	ExtType string
    62  	ExtData string
    63  }
    64  
    65  func fileInfoFromStat(stat *FileStat, name string) os.FileInfo {
    66  	return &fileInfo{
    67  		name: name,
    68  		stat: stat,
    69  	}
    70  }
    71  
    72  // FileInfoUidGid extends os.FileInfo and adds callbacks for Uid and Gid retrieval,
    73  // as an alternative to *syscall.Stat_t objects on unix systems.
    74  type FileInfoUidGid interface {
    75  	os.FileInfo
    76  	Uid() uint32
    77  	Gid() uint32
    78  }
    79  
    80  // FileInfoUidGid extends os.FileInfo and adds a callbacks for extended data retrieval.
    81  type FileInfoExtendedData interface {
    82  	os.FileInfo
    83  	Extended() []StatExtended
    84  }
    85  
    86  func fileStatFromInfo(fi os.FileInfo) (uint32, *FileStat) {
    87  	mtime := fi.ModTime().Unix()
    88  	atime := mtime
    89  	var flags uint32 = sshFileXferAttrSize |
    90  		sshFileXferAttrPermissions |
    91  		sshFileXferAttrACmodTime
    92  
    93  	fileStat := &FileStat{
    94  		Size:  uint64(fi.Size()),
    95  		Mode:  fromFileMode(fi.Mode()),
    96  		Mtime: uint32(mtime),
    97  		Atime: uint32(atime),
    98  	}
    99  
   100  	// os specific file stat decoding
   101  	fileStatFromInfoOs(fi, &flags, fileStat)
   102  
   103  	// The call above will include the sshFileXferAttrUIDGID in case
   104  	// the os.FileInfo can be casted to *syscall.Stat_t on unix.
   105  	// If fi implements FileInfoUidGid, retrieve Uid, Gid from it instead.
   106  	if fiExt, ok := fi.(FileInfoUidGid); ok {
   107  		flags |= sshFileXferAttrUIDGID
   108  		fileStat.UID = fiExt.Uid()
   109  		fileStat.GID = fiExt.Gid()
   110  	}
   111  
   112  	// if fi implements FileInfoExtendedData, retrieve extended data from it
   113  	if fiExt, ok := fi.(FileInfoExtendedData); ok {
   114  		fileStat.Extended = fiExt.Extended()
   115  		if len(fileStat.Extended) > 0 {
   116  			flags |= sshFileXferAttrExtended
   117  		}
   118  	}
   119  
   120  	return flags, fileStat
   121  }