xattr: add -s(ymlink) flag

On Linux and FreeBSD-derivatives, it is possible to set extended
attributes on symlinks themselves (in addition to their targets). This
was already supported by the xattr library, but we didn't expose it in
the CLI interface. Borrow the flag from the MacOS tool we borrow our
flag conventions from[1].

[1]: https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man1/xattr.1.html

Signed-off-by: Aleksa Sarai <asarai@suse.de>

1 files changed, 14 insertions, 6 deletions

diff --git a/xattr/tool.py b/xattr/tool.py
index 5cdecbd..a7cfb47 100755
--- a/xattr/tool.py
+++ b/xattr/tool.py
@@ -45,10 +45,10 @@ def usage(e=None):
         print("")
 
     name = os.path.basename(sys.argv[0])
-    print("usage: %s [-lz] file [file ...]" % (name,))
-    print("       %s -p [-lz] attr_name file [file ...]" % (name,))
-    print("       %s -w [-z] attr_name attr_value file [file ...]" % (name,))
-    print("       %s -d attr_name file [file ...]" % (name,))
+    print("usage: %s [-slz] file [file ...]" % (name,))
+    print("       %s -p [-slz] attr_name file [file ...]" % (name,))
+    print("       %s -w [-sz] attr_name attr_value file [file ...]" % (name,))
+    print("       %s -d [-s] attr_name file [file ...]" % (name,))
     print("")
     print("The first form lists the names of all xattrs on the given file(s).")
     print("The second form (-p) prints the value of the xattr attr_name.")
@@ -57,6 +57,7 @@ def usage(e=None):
     print("")
     print("options:")
     print("  -h: print this help")
+    print("  -s: act on symbolic links themselves rather than their targets")
     print("  -l: print long format (attr_name: attr_value)")
     print("  -z: compress or decompress (if compressed) attribute value in zip format")
 
@@ -81,7 +82,7 @@ def _dump(src, length=16):
 
 def main():
     try:
-        (optargs, args) = getopt.getopt(sys.argv[1:], "hlpwdz", ["help"])
+        (optargs, args) = getopt.getopt(sys.argv[1:], "hlpwdzs", ["help"])
     except getopt.GetoptError as e:
         usage(e)
 
@@ -90,6 +91,7 @@ def main():
     read = False
     write = False
     delete = False
+    nofollow = False
     compress = lambda x: x
     decompress = compress
     status = 0
@@ -99,6 +101,8 @@ def main():
             usage()
         elif opt == "-l":
             long_format = True
+        elif opt == "-s":
+            nofollow = True
         elif opt == "-p":
             read = True
             if write or delete:
@@ -134,6 +138,10 @@ def main():
     else:
         multiple_files = False
 
+    options = 0
+    if nofollow:
+        options |= xattr.XATTR_NOFOLLOW
+
     for filename in args:
         def onError(e):
             if not os.path.exists(filename):
@@ -142,7 +150,7 @@ def main():
                 sys.stderr.write(str(e) + "\n")
 
         try:
-            attrs = xattr.xattr(filename)
+            attrs = xattr.xattr(filename, options=options)
         except (IOError, OSError) as e:
             onError(e)
             continue