pk-crypto: Add pretty-printer to 'gcry-error' exceptions.

* guix/pk-crypto.scm (string->canonical-sexp, sign, generate-key): Pass
  the procedure name as the first argument to 'throw'.
  (gcrypt-error-printer): New procedure.
  <top level>: Add call to 'set-exception-printer!'.
* guix/nar.scm (restore-one-item): Add 'proc' parameter to 'catch'
  handler for 'gcry-error.
* guix/scripts/archive.scm (%options, generate-key-pair, authorize-key):
  Likewise.
* guix/scripts/substitute-binary.scm (narinfo-signature->canonical-sexp):
  Likewise.

guix/nar.scm

@@ -370,7 +370,7 @@ protected from GC."
     (let ((signature (catch 'gcry-error
                        (lambda ()
                          (string->canonical-sexp signature))
-                       (lambda (err . _)
+                       (lambda (key proc err)
                          (raise (condition
                                  (&message
                                   (message "signature is not a valid \

guix/pk-crypto.scm

@@ -143,7 +143,7 @@ thrown along with 'gcry-error'."
              (err  (proc sexp (string->pointer str "ISO-8859-1") 0 1)))
         (if (= 0 err)
             (pointer->canonical-sexp (dereference-pointer sexp))
-            (throw 'gcry-error err))))))
+            (throw 'gcry-error 'string->canonical-sexp err))))))
 
 (define-syntax GCRYSEXP_FMT_ADVANCED
   (identifier-syntax 3))
@@ -296,7 +296,7 @@ is 'private-key'.)"
                         (canonical-sexp->pointer secret-key))))
         (if (= 0 err)
             (pointer->canonical-sexp (dereference-pointer sig))
-            (throw 'gry-error err))))))
+            (throw 'gcry-error 'sign err))))))
 
 (define verify
   (let* ((ptr  (libgcrypt-func "gcry_pk_verify"))
@@ -318,7 +318,7 @@ s-expression like: (genkey (rsa (nbits 4:2048)))."
              (err (proc key (canonical-sexp->pointer params))))
         (if (zero? err)
             (pointer->canonical-sexp (dereference-pointer key))
-            (throw 'gcry-error err))))))
+            (throw 'gcry-error 'generate-key err))))))
 
 (define find-sexp-token
   (let* ((ptr  (libgcrypt-func "gcry_sexp_find_token"))
@@ -403,4 +403,13 @@ use pattern matching."
 
        (write sexp)))))
 
+(define (gcrypt-error-printer port key args default-printer)
+  "Print the gcrypt error specified by ARGS."
+  (match args
+    ((proc err)
+     (format port "In procedure ~a: ~a: ~a"
+             proc (error-source err) (error-string err)))))
+
+(set-exception-printer! 'gcry-error gcrypt-error-printer)
+
 ;;; pk-crypto.scm ends here

guix/scripts/archive.scm

@@ -123,7 +123,7 @@ Export/import one or more packages from/to the store.\n"))
                               (string->canonical-sexp
                                (or arg %key-generation-parameters))))
                          (alist-cons 'generate-key params result)))
-                     (lambda (key err)
+                     (lambda (key proc err)
                        (leave (_ "invalid key generation parameters: ~a: ~a~%")
                               (error-source err)
                               (error-string err))))))
@@ -248,7 +248,7 @@ this may take time...~%"))
   (let* ((pair   (catch 'gcry-error
                    (lambda ()
                      (generate-key parameters))
-                   (lambda (key err)
+                   (lambda (key proc err)
                      (leave (_ "key generation failed: ~a: ~a~%")
                             (error-source err)
                             (error-string err)))))
@@ -275,7 +275,7 @@ the input port."
     (catch 'gcry-error
       (lambda ()
         (string->canonical-sexp (get-string-all (current-input-port))))
-      (lambda (key err)
+      (lambda (key proc err)
         (leave (_ "failed to read public key: ~a: ~a~%")
                (error-source err) (error-string err)))))
 

guix/scripts/substitute-binary.scm

@@ -252,7 +252,7 @@ failure."
                 (catch 'gcry-error
                   (lambda ()
                     (string->canonical-sexp signature))
-                  (lambda (err . rest)
+                  (lambda (key proc err)
                     (leave (_ "signature is not a valid \
 s-expression: ~s~%")
                            signature))))))))