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-rw-r--r--gnu/services.scm32
1 files changed, 32 insertions, 0 deletions
diff --git a/gnu/services.scm b/gnu/services.scm
index f6dc56d940..6509a9014e 100644
--- a/gnu/services.scm
+++ b/gnu/services.scm
@@ -89,6 +89,7 @@
system-service-type
provenance-service-type
+ system-provenance
boot-service-type
cleanup-service-type
activation-service-type
@@ -423,6 +424,19 @@ be parsed by tools; it's potentially more future-proof than code."
(branch ,(channel-branch channel))
(commit ,(channel-commit channel))))
+(define (sexp->channel sexp)
+ "Return the channel corresponding to SEXP, an sexp as found in the
+\"provenance\" file produced by 'provenance-service-type'."
+ (match sexp
+ (('channel ('name name)
+ ('url url)
+ ('branch branch)
+ ('commit commit)
+ rest ...)
+ ;; XXX: In the future REST may include a channel introduction.
+ (channel (name name) (url url)
+ (branch branch) (commit commit)))))
+
(define (provenance-file channels config-file)
"Return a 'provenance' file describing CHANNELS, a list of channels, and
CONFIG-FILE, which can be either #f or a <local-file> containing the OS
@@ -474,6 +488,24 @@ channels in use and CONFIG-FILE, if it is true."
itself: the channels used when building the system, and its configuration
file, when available.")))
+(define (system-provenance system)
+ "Given SYSTEM, the file name of a system generation, return two values: the
+list of channels SYSTEM is built from, and its configuration file. If that
+information is missing, return the empty list (for channels) and possibly
+#false (for the configuration file)."
+ (catch 'system-error
+ (lambda ()
+ (match (call-with-input-file (string-append system "/provenance")
+ read)
+ (('provenance ('version 0)
+ ('channels channels ...)
+ ('configuration-file config-file))
+ (values (map sexp->channel channels)
+ config-file))
+ (_
+ (values '() #f))))
+ (lambda _
+ (values '() #f))))
;;;
;;; Cleanup.