From: Dmitry Bogatov <[email protected]>
* module/ice-9/xattr.scm (xattr-get): convert exception to #f
if errno was ENOATTR
---
module/ice-9/xattr.scm | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/module/ice-9/xattr.scm b/module/ice-9/xattr.scm
index 090b233..804d374 100644
--- a/module/ice-9/xattr.scm
+++ b/module/ice-9/xattr.scm
@@ -101,14 +101,25 @@
(%ret = (if (port? file)
(c-attr-getf (port->fdes file) attrname attrvalue
valuelength flags)
(c-attr-get file attrname attrvalue valuelength flags)))
- (unless (zero? %ret)
- (c-scm-syserror "xattr-get"))
;; No matter how long actual value is, attrvalue is bytevector
;; with length of `max-valuelen'. We need only first `valuelength'
;; from it. It is unexpectedly complicated to splice bytevectory.
- (let ()
- (define value
- (pointer->bytevector (bytevector->pointer attrvalue) valuelength))
- (if decode?
- (bytevector->string value "utf-8")
- (bytevector-copy value)))))
+ (define result
+ (delay
+ (let ((value (pointer->bytevector (bytevector->pointer attrvalue)
+ valuelength)))
+ (if decode?
+ (bytevector->string value "utf-8")
+ (bytevector-copy value))))) ; unshare with 64Kb bytevector
+ (define (xattr-get/syserror) (c-scm-syserror "xattr-get"))
+ ;; Really ugly way to get errno. We throw exception via internal
+ ;; Guile function 'scm_syserror' just to catch it and extract errno.
+ ;; If it is ENODATA (ENOATTR in manual page) it is not exceptional,
+ ;; and we return #f.
+ (if (zero? %ret)
+ (force result)
+ (catch #t xattr-get/syserror
+ (lambda _args
+ (unless (eqv? ENODATA (system-error-errno _args))
+ (xattr-get/syserror))
+ #f)))))
--
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