Merge branch 'master' into core-updates

7 files changed, 672 insertions, 29 deletions

diff --git a/guix/build-system/haskell.scm b/guix/build-system/haskell.scm
new file mode 100644
index 0000000000..79faa5a09e
--- /dev/null
+++ b/guix/build-system/haskell.scm
@@ -0,0 +1,135 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 Federico Beffa <beffa@fbengineering.ch>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix build-system haskell)
+  #:use-module (guix store)
+  #:use-module (guix utils)
+  #:use-module (guix packages)
+  #:use-module (guix derivations)
+  #:use-module (guix build-system)
+  #:use-module (guix build-system gnu)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-26)
+  #:export (haskell-build
+            haskell-build-system))
+
+;; Commentary:
+;;
+;; Standard build procedure for Haskell packages using 'Setup.hs'.  This is
+;; implemented as an extension of 'gnu-build-system'.
+;;
+;; Code:
+
+(define (default-haskell)
+  "Return the default Haskell package."
+  ;; Lazily resolve the binding to avoid a circular dependency.
+  (let ((haskell (resolve-interface '(gnu packages haskell))))
+    (module-ref haskell 'ghc)))
+
+(define* (lower name
+                #:key source inputs native-inputs outputs system target
+                (haskell (default-haskell))
+                #:allow-other-keys
+                #:rest arguments)
+  "Return a bag for NAME."
+  (define private-keywords
+    '(#:target #:haskell #:inputs #:native-inputs))
+
+  (and (not target)                               ;XXX: no cross-compilation
+       (bag
+         (name name)
+         (system system)
+         (host-inputs `(,@(if source
+                              `(("source" ,source))
+                              '())
+                        ,@inputs
+
+                        ;; Keep the standard inputs of 'gnu-build-system'.
+                        ,@(standard-packages)))
+         (build-inputs `(("haskell" ,haskell)
+                         ,@native-inputs))
+         (outputs outputs)
+         (build haskell-build)
+         (arguments (strip-keyword-arguments private-keywords arguments)))))
+
+(define* (haskell-build store name inputs
+                        #:key source
+                        (haddock? #t)
+                        (haddock-flags ''())
+                        (tests? #t)
+                        (test-target "test")
+                        (configure-flags ''())
+                        (phases '(@ (guix build haskell-build-system)
+                                    %standard-phases))
+                        (outputs '("out"))
+                        (search-paths '())
+                        (system (%current-system))
+                        (guile #f)
+                        (imported-modules '((guix build haskell-build-system)
+                                            (guix build gnu-build-system)
+                                            (guix build utils)))
+                        (modules '((guix build haskell-build-system)
+                                   (guix build utils))))
+  "Build SOURCE using HASKELL, and with INPUTS.  This assumes that SOURCE
+provides a 'Setup.hs' file as its build system."
+  (define builder
+    `(begin
+       (use-modules ,@modules)
+       (haskell-build #:name ,name
+                      #:source ,(match (assoc-ref inputs "source")
+                                  (((? derivation? source))
+                                   (derivation->output-path source))
+                                  ((source)
+                                   source)
+                                  (source
+                                   source))
+                      #:configure-flags ,configure-flags
+                      #:haddock-flags ,haddock-flags
+                      #:system ,system
+                      #:test-target ,test-target
+                      #:tests? ,tests?
+                      #:haddock? ,haddock?
+                      #:phases ,phases
+                      #:outputs %outputs
+                      #:search-paths ',(map search-path-specification->sexp
+                                            search-paths)
+                      #:inputs %build-inputs)))
+
+  (define guile-for-build
+    (match guile
+      ((? package?)
+       (package-derivation store guile system #:graft? #f))
+      (#f                                         ; the default
+       (let* ((distro (resolve-interface '(gnu packages commencement)))
+              (guile  (module-ref distro 'guile-final)))
+         (package-derivation store guile system #:graft? #f)))))
+
+  (build-expression->derivation store name builder
+                                #:inputs inputs
+                                #:system system
+                                #:modules imported-modules
+                                #:outputs outputs
+                                #:guile-for-build guile-for-build))
+
+(define haskell-build-system
+  (build-system
+    (name 'haskell)
+    (description "The standard Haskell build system")
+    (lower lower)))
+
+;;; haskell.scm ends here
diff --git a/guix/build/glib-or-gtk-build-system.scm b/guix/build/glib-or-gtk-build-system.scm
index 9c0104365d..15d7de2236 100644
--- a/guix/build/glib-or-gtk-build-system.scm
+++ b/guix/build/glib-or-gtk-build-system.scm
@@ -140,7 +140,9 @@ add a dependency of that output on GLib and GTK+."
      ((output . directory)
       (unless (member output glib-or-gtk-wrap-excluded-outputs)
         (let* ((bindir       (string-append directory "/bin"))
-               (bin-list     (find-files bindir ".*"))
+               (libexecdir   (string-append directory "/libexec"))
+               (bin-list     (append (find-files bindir ".*")
+                                     (find-files libexecdir ".*")))
                (datadirs     (data-directories
                               (alist-cons output directory inputs)))
                (gtk-mod-dirs (gtk-module-directories
diff --git a/guix/build/haskell-build-system.scm b/guix/build/haskell-build-system.scm
new file mode 100644
index 0000000000..52b9c79d2f
--- /dev/null
+++ b/guix/build/haskell-build-system.scm
@@ -0,0 +1,220 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 Federico Beffa <beffa@fbengineering.ch>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix build haskell-build-system)
+  #:use-module ((guix build gnu-build-system) #:prefix gnu:)
+  #:use-module (guix build utils)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (ice-9 rdelim)
+  #:use-module (ice-9 regex)
+  #:use-module (ice-9 match)
+  #:export (%standard-phases
+            haskell-build))
+
+;; Commentary:
+;;
+;; Builder-side code of the standard Haskell package build procedure.
+;;
+;; The Haskell compiler, to find libraries, relies on a library database with
+;; a binary cache. For GHC the cache has to be named 'package.cache'. If every
+;; library would generate the cache at build time, then they would clash in
+;; profiles. For this reason we do not generate the cache when we generate
+;; libraries substitutes. Instead:
+;;
+;; - At build time we use the 'setup-compiler' phase to generate a temporary
+;;   library database and its cache.
+;;
+;; - We generate the cache when a profile is created.
+;;
+;; Code:
+
+;; Directory where we create the temporary libraries database with its cache
+;; as required by the compiler.
+(define %tmp-db-dir
+  (string-append (or (getenv "TMP") "/tmp")
+                 "/package.conf.d"))
+
+(define (run-setuphs command params)
+  (let ((setup-file (cond
+                     ((file-exists? "Setup.hs")
+                      "Setup.hs")
+                     ((file-exists? "Setup.lhs")
+                      "Setup.lhs")
+                     (else
+                      #f))))
+    (if setup-file
+        (begin
+          (format #t "running \"runhaskell Setup.hs\" with command ~s \
+and parameters ~s~%"
+                  command params)
+          (zero? (apply system* "runhaskell" setup-file command params)))
+        (error "no Setup.hs nor Setup.lhs found"))))
+
+(define* (configure #:key outputs inputs tests? (configure-flags '())
+                    #:allow-other-keys)
+  "Configure a given Haskell package."
+  (let* ((out (assoc-ref outputs "out"))
+         (input-dirs (match inputs
+                       (((_ . dir) ...)
+                        dir)
+                       (_ '())))
+         (params (append `(,(string-append "--prefix=" out))
+                         `(,(string-append
+                             "--docdir=" out "/share/doc/"
+                             (package-name-version out)))
+                         `(,(string-append "--package-db=" %tmp-db-dir))
+                         '("--global")
+                         `(,(string-append
+                             "--extra-include-dirs="
+                             (list->search-path-as-string
+                              (search-path-as-list '("include") input-dirs)
+                              ":")))
+                         `(,(string-append
+                             "--extra-lib-dirs="
+                             (list->search-path-as-string
+                              (search-path-as-list '("lib") input-dirs)
+                              ":")))
+                         (if tests?
+                             '("--enable-tests")
+                             '())
+                         configure-flags)))
+    (run-setuphs "configure" params)))
+
+(define* (build #:rest empty)
+  "Build a given Haskell package."
+  (run-setuphs "build" '()))
+
+(define* (install #:rest empty)
+  "Install a given Haskell package."
+  (run-setuphs "copy" '()))
+
+(define (package-name-version store-dir)
+  "Given a store directory STORE-DIR return 'name-version' of the package."
+  (let* ((base (basename store-dir)))
+    (string-drop base
+                 (+ 1 (string-index base #\-)))))
+
+(define (grep rx port)
+  "Given a regular-expression RX including a group, read from PORT until the
+first match and return the content of the group."
+  (let ((line (read-line port)))
+    (if (eof-object? line)
+        #f
+        (let ((rx-result (regexp-exec rx line)))
+          (if rx-result
+              (match:substring rx-result 1)
+              (grep rx port))))))
+
+(define* (setup-compiler #:key system inputs outputs #:allow-other-keys)
+  "Setup the compiler environment."
+  (let* ((haskell (assoc-ref inputs "haskell"))
+         (name-version (package-name-version haskell)))
+    (cond
+     ((string-match "ghc" name-version)
+      (make-ghc-package-database system inputs outputs))
+     (else
+      (format #t
+              "Compiler ~a not supported~%" name-version)))))
+
+(define (make-ghc-package-database system inputs outputs)
+  "Generate the GHC package database."
+  (let* ((haskell  (assoc-ref inputs "haskell"))
+         (input-dirs (match inputs
+                       (((_ . dir) ...)
+                        dir)
+                       (_ '())))
+         (conf-dirs (search-path-as-list
+                     `(,(string-append "lib/" system "-"
+                                       (package-name-version haskell)
+                                       "/package.conf.d"))
+                     input-dirs))
+         (conf-files (append-map (cut find-files <> "\\.conf$") conf-dirs)))
+    (mkdir-p %tmp-db-dir)
+    (for-each (lambda (file)
+                (copy-file file
+                           (string-append %tmp-db-dir "/" (basename file))))
+              conf-files)
+    (zero? (system* "ghc-pkg"
+                    (string-append "--package-db=" %tmp-db-dir)
+                    "recache"))))
+
+(define* (register #:key name system inputs outputs #:allow-other-keys)
+  "Generate the compiler registration file for a given Haskell package.  Don't
+generate the cache as it would clash in user profiles."
+  (let* ((out (assoc-ref outputs "out"))
+         (haskell  (assoc-ref inputs "haskell"))
+         (lib (string-append out "/lib"))
+         (config-dir (string-append lib "/" system
+                                    "-" (package-name-version haskell)
+                                    "/package.conf.d"))
+         (id-rx (make-regexp "^id: *(.*)$"))
+         (lib-rx (make-regexp "lib.*\\.(a|so)"))
+         (config-file (string-append config-dir "/" name ".conf"))
+         (params
+          (list (string-append "--gen-pkg-config=" config-file))))
+    (unless (null? (find-files lib lib-rx))
+      (mkdir-p config-dir)
+      (run-setuphs "register" params)
+      (let ((config-file-name+id
+             (call-with-ascii-input-file config-file (cut grep id-rx <>))))
+        (rename-file config-file
+                     (string-append config-dir "/" config-file-name+id
+                                    ".conf"))))
+    #t))
+
+(define* (check #:key tests? test-target #:allow-other-keys)
+  "Run the test suite of a given Haskell package."
+  (if tests?
+      (run-setuphs test-target '())
+      (begin
+        (format #t "test suite not run~%")
+        #t)))
+
+(define* (haddock #:key outputs haddock? haddock-flags #:allow-other-keys)
+  "Run the test suite of a given Haskell package."
+  (if haddock?
+      (let* ((out (assoc-ref outputs "out"))
+             (doc-src (string-append (getcwd) "/dist/doc"))
+             (doc-dest (string-append out "/share/doc/"
+                                      (package-name-version out))))
+        (if (run-setuphs "haddock" haddock-flags)
+            (begin
+              (copy-recursively doc-src doc-dest)
+              #t)
+            #f))
+      #t))
+
+(define %standard-phases
+  (modify-phases gnu:%standard-phases
+    (add-before configure setup-compiler setup-compiler)
+    (add-after install haddock haddock)
+    (add-after install register register)
+    (replace install install)
+    (replace check check)
+    (replace build build)
+    (replace configure configure)))
+
+(define* (haskell-build #:key inputs (phases %standard-phases)
+                        #:allow-other-keys #:rest args)
+  "Build the given Haskell package, applying all of PHASES in order."
+  (apply gnu:gnu-build
+         #:inputs inputs #:phases phases
+         args))
+
+;;; haskell-build-system.scm ends here
diff --git a/guix/scripts/package.scm b/guix/scripts/package.scm
index 3cc7ae760f..6190f3286d 100644
--- a/guix/scripts/package.scm
+++ b/guix/scripts/package.scm
@@ -232,6 +232,41 @@ DURATION-RELATION with the current time."
          filter-by-duration)
         (else #f)))
 
+(define (delete-matching-generations store profile pattern)
+  "Delete from PROFILE all the generations matching PATTERN.  PATTERN must be
+a string denoting a set of generations: the empty list means \"all generations
+but the current one\", a number designates a generation, and other patterns
+denote ranges as interpreted by 'matching-derivations'."
+  (let ((current (generation-number profile)))
+    (cond ((not (file-exists? profile))            ; XXX: race condition
+           (raise (condition (&profile-not-found-error
+                              (profile profile)))))
+          ((string-null? pattern)
+           (delete-generations (%store) profile
+                               (delv current (profile-generations profile))))
+          ;; Do not delete the zeroth generation.
+          ((equal? 0 (string->number pattern))
+           #t)
+
+          ;; If PATTERN is a duration, match generations that are
+          ;; older than the specified duration.
+          ((matching-generations pattern profile
+                                 #:duration-relation >)
+           =>
+           (lambda (numbers)
+             (when (memv current numbers)
+               (warning (_ "not removing generation ~a, which is current~%")
+                        current))
+
+             ;; Make sure we don't inadvertently remove the current
+             ;; generation.
+             (let ((numbers (delv current numbers)))
+               (when (null-list? numbers)
+                 (leave (_ "no matching generation~%")))
+               (delete-generations (%store) profile numbers))))
+          (else
+           (leave (_ "invalid syntax: ~a~%") pattern)))))
+
 
 ;;;
 ;;; Package specifications.
@@ -751,9 +786,6 @@ more information.~%"))
     (define dry-run? (assoc-ref opts 'dry-run?))
     (define profile  (assoc-ref opts 'profile))
 
-    (define current-generation-number
-      (generation-number profile))
-
     ;; First roll back if asked to.
     (cond ((and (assoc-ref opts 'roll-back?)
                 (not dry-run?))
@@ -782,30 +814,7 @@ more information.~%"))
            (for-each
             (match-lambda
              (('delete-generations . pattern)
-              (cond ((not (file-exists? profile)) ; XXX: race condition
-                     (raise (condition (&profile-not-found-error
-                                        (profile profile)))))
-                    ((string-null? pattern)
-                     (delete-generations
-                      (%store) profile
-                      (delete current-generation-number
-                              (profile-generations profile))))
-                    ;; Do not delete the zeroth generation.
-                    ((equal? 0 (string->number pattern))
-                     (exit 0))
-
-                    ;; If PATTERN is a duration, match generations that are
-                    ;; older than the specified duration.
-                    ((matching-generations pattern profile
-                                           #:duration-relation >)
-                     =>
-                     (lambda (numbers)
-                       (if (null-list? numbers)
-                           (exit 1)
-                           (delete-generations (%store) profile numbers))))
-                    (else
-                     (leave (_ "invalid syntax: ~a~%")
-                            pattern)))
+              (delete-matching-generations (%store) profile pattern)
 
               (process-actions
                (alist-delete 'delete-generations opts)))
diff --git a/guix/scripts/publish.scm b/guix/scripts/publish.scm
new file mode 100644
index 0000000000..c7c66fefbe
--- /dev/null
+++ b/guix/scripts/publish.scm
@@ -0,0 +1,243 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 David Thompson <davet@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix scripts publish)
+  #:use-module ((system repl server) #:prefix repl:)
+  #:use-module (ice-9 binary-ports)
+  #:use-module (ice-9 format)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 regex)
+  #:use-module (rnrs io ports)
+  #:use-module (rnrs bytevectors)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-2)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-37)
+  #:use-module (web http)
+  #:use-module (web request)
+  #:use-module (web response)
+  #:use-module (web server)
+  #:use-module (web uri)
+  #:use-module (guix base32)
+  #:use-module (guix base64)
+  #:use-module (guix config)
+  #:use-module (guix derivations)
+  #:use-module (guix hash)
+  #:use-module (guix pki)
+  #:use-module (guix pk-crypto)
+  #:use-module (guix store)
+  #:use-module (guix serialization)
+  #:use-module (guix ui)
+  #:export (guix-publish))
+
+(define (show-help)
+  (format #t (_ "Usage: guix publish [OPTION]...
+Publish ~a over HTTP.\n") %store-directory)
+  (display (_ "
+  -p, --port=PORT        listen on PORT"))
+  (display (_ "
+  -r, --repl[=PORT]      spawn REPL server on PORT"))
+  (newline)
+  (display (_ "
+  -h, --help             display this help and exit"))
+  (display (_ "
+  -V, --version          display version information and exit"))
+  (newline)
+  (show-bug-report-information))
+
+(define %options
+  (list (option '(#\h "help") #f #f
+                (lambda _
+                  (show-help)
+                  (exit 0)))
+        (option '(#\V "version") #f #f
+                (lambda _
+                  (show-version-and-exit "guix publish")))
+        (option '(#\p "port") #t #f
+                (lambda (opt name arg result)
+                  (alist-cons 'port (string->number* arg) result)))
+        (option '(#\r "repl") #f #t
+                (lambda (opt name arg result)
+                  ;; If port unspecified, use default Guile REPL port.
+                  (let ((port (and arg (string->number* arg))))
+                    (alist-cons 'repl (or port 37146) result))))))
+
+(define %default-options
+  '((port . 8080)
+    (repl . #f)))
+
+(define (lazy-read-file-sexp file)
+  "Return a promise to read the canonical sexp from FILE."
+  (delay
+    (call-with-input-file file
+      (compose string->canonical-sexp
+               get-string-all))))
+
+(define %private-key
+  (lazy-read-file-sexp %private-key-file))
+
+(define %public-key
+  (lazy-read-file-sexp %public-key-file))
+
+(define %nix-cache-info
+  `(("StoreDir" . ,%store-directory)
+    ("WantMassQuery" . 0)
+    ("Priority" . 100)))
+
+(define (load-derivation file)
+  "Read the derivation from FILE."
+  (call-with-input-file file read-derivation))
+
+(define (signed-string s)
+  "Sign the hash of the string S with the daemon's key."
+  (let* ((public-key (force %public-key))
+         (hash (bytevector->hash-data (sha256 (string->utf8 s))
+                                      #:key-type (key-type public-key))))
+    (signature-sexp hash (force %private-key) public-key)))
+
+(define base64-encode-string
+  (compose base64-encode string->utf8))
+
+(define (narinfo-string store-path path-info key)
+  "Generate a narinfo key/value string for STORE-PATH using the details in
+PATH-INFO.  The narinfo is signed with KEY."
+  (let* ((url        (string-append "nar/" (basename store-path)))
+         (hash       (bytevector->base32-string
+                      (path-info-hash path-info)))
+         (size       (path-info-nar-size path-info))
+         (references (string-join
+                      (map basename (path-info-references path-info))
+                      " "))
+         (deriver (path-info-deriver path-info))
+         (base-info  (format #f
+                             "StorePath: ~a
+URL: ~a
+Compression: none
+NarHash: sha256:~a
+NarSize: ~d
+References: ~a~%"
+                             store-path url hash size references))
+         ;; Do not render a "Deriver" or "System" line if we are rendering
+         ;; info for a derivation.
+         (info (if (string-null? deriver)
+                   base-info
+                   (let ((drv (load-derivation deriver)))
+                     (format #f "~aSystem: ~a~%Deriver: ~a~%"
+                             base-info (derivation-system drv)
+                             (basename deriver)))))
+         (signature  (base64-encode-string
+                      (canonical-sexp->string (signed-string info)))))
+    (format #f "~aSignature: 1;~a;~a~%" info (gethostname) signature)))
+
+(define (not-found request)
+  "Render 404 response for REQUEST."
+  (values (build-response #:code 404)
+          (string-append "Resource not found: "
+                         (uri-path (request-uri request)))))
+
+(define (render-nix-cache-info)
+  "Render server information."
+  (values '((content-type . (text/plain)))
+          (lambda (port)
+            (for-each (match-lambda
+                       ((key . value)
+                        (format port "~a: ~a~%" key value)))
+                      %nix-cache-info))))
+
+(define (render-narinfo store request hash)
+  "Render metadata for the store path corresponding to HASH."
+  (let* ((store-path (hash-part->path store hash))
+         (path-info (and (not (string-null? store-path))
+                         (query-path-info store store-path))))
+    (if path-info
+        (values '((content-type . (application/x-nix-narinfo)))
+                (cut display
+                     (narinfo-string store-path path-info (force %private-key))
+                     <>))
+        (not-found request))))
+
+(define (render-nar request store-item)
+  "Render archive of the store path corresponding to STORE-ITEM."
+  (let ((store-path (string-append %store-directory "/" store-item)))
+    ;; The ISO-8859-1 charset *must* be used otherwise HTTP clients will
+    ;; interpret the byte stream as UTF-8 and arbitrarily change invalid byte
+    ;; sequences.
+    (if (file-exists? store-path)
+        (values '((content-type . (application/x-nix-archive
+                                   (charset . "ISO-8859-1"))))
+                (lambda (port)
+                  (write-file store-path port)))
+        (not-found request))))
+
+(define extract-narinfo-hash
+  (let ((regexp (make-regexp "^([a-df-np-sv-z0-9]{32}).narinfo$")))
+    (lambda (str)
+      "Return the hash within the narinfo resource string STR, or false if STR
+is invalid."
+      (and=> (regexp-exec regexp str)
+             (cut match:substring <> 1)))))
+
+(define (get-request? request)
+  "Return #t if REQUEST uses the GET method."
+  (eq? (request-method request) 'GET))
+
+(define (request-path-components request)
+  "Split the URI path of REQUEST into a list of component strings.  For
+example: \"/foo/bar\" yields '(\"foo\" \"bar\")."
+  (split-and-decode-uri-path (uri-path (request-uri request))))
+
+(define (make-request-handler store)
+  (lambda (request body)
+    (format #t "~a ~a~%"
+            (request-method request)
+            (uri-path (request-uri request)))
+    (if (get-request? request) ; reject POST, PUT, etc.
+        (match (request-path-components request)
+          ;; /nix-cache-info
+          (("nix-cache-info")
+           (render-nix-cache-info))
+          ;; /<hash>.narinfo
+          (((= extract-narinfo-hash (? string? hash)))
+           (render-narinfo store request hash))
+          ;; /nar/<store-item>
+          (("nar" store-item)
+           (render-nar request store-item))
+          (_ (not-found request)))
+        (not-found request))))
+
+(define (run-publish-server port store)
+  (run-server (make-request-handler store)
+              'http
+              `(#:addr ,INADDR_ANY
+                #:port ,port)))
+
+(define (guix-publish . args)
+  (with-error-handling
+    (let* ((opts (args-fold* args %options
+                             (lambda (opt name arg result)
+                               (leave (_ "~A: unrecognized option~%") name))
+                             (lambda (arg result)
+                               (leave (_ "~A: extraneuous argument~%") arg))
+                             %default-options))
+           (port (assoc-ref opts 'port))
+           (repl-port (assoc-ref opts 'repl)))
+      (format #t (_ "publishing ~a on port ~d~%") %store-directory port)
+      (when repl-port
+        (repl:spawn-server (repl:make-tcp-server-socket #:port repl-port)))
+      (with-store store
+        (run-publish-server (assoc-ref opts 'port) store)))))
diff --git a/guix/store.scm b/guix/store.scm
index 3d6b06989c..10b9062db2 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -60,6 +60,7 @@
             valid-path?
             query-path-hash
             hash-part->path
+            query-path-info
             add-text-to-store
             add-to-store
             build-things
@@ -79,6 +80,13 @@
             substitutable-paths
             substitutable-path-info
 
+            path-info?
+            path-info-deriver
+            path-info-hash
+            path-info-references
+            path-info-registration-time
+            path-info-nar-size
+
             references
             requisites
             referrers
@@ -212,6 +220,24 @@
                 (cons (substitutable path deriver refs dl-size nar-size)
                       result))))))
 
+;; Information about a store path.
+(define-record-type <path-info>
+  (path-info deriver hash references registration-time nar-size)
+  path-info?
+  (deriver path-info-deriver)
+  (hash path-info-hash)
+  (references path-info-references)
+  (registration-time path-info-registration-time)
+  (nar-size path-info-nar-size))
+
+(define (read-path-info p)
+  (let ((deriver  (read-store-path p))
+        (hash     (base16-string->bytevector (read-string p)))
+        (refs     (read-store-path-list p))
+        (registration-time (read-int p))
+        (nar-size (read-long-long p)))
+    (path-info deriver hash refs registration-time nar-size)))
+
 (define-syntax write-arg
   (syntax-rules (integer boolean file string string-list string-pairs
                  store-path store-path-list base16)
@@ -236,7 +262,7 @@
 
 (define-syntax read-arg
   (syntax-rules (integer boolean string store-path store-path-list
-                 substitutable-path-list base16)
+                 substitutable-path-list path-info base16)
     ((_ integer p)
      (read-int p))
     ((_ boolean p)
@@ -249,6 +275,8 @@
      (read-store-path-list p))
     ((_ substitutable-path-list p)
      (read-substitutable-path-list p))
+    ((_ path-info p)
+     (read-path-info p))
     ((_ base16 p)
      (base16-string->bytevector (read-string p)))))
 
@@ -541,6 +569,10 @@ string).  Raise an error if no such path exists."
      ;; /HASH.narinfo.
      (query-path-from-hash-part server hash-part))))
 
+(define-operation (query-path-info (store-path path))
+  "Return the info (hash, references, etc.) for PATH."
+  path-info)
+
 (define add-text-to-store
   ;; A memoizing version of `add-to-store', to avoid repeated RPCs with
   ;; the very same arguments during a given session.
diff --git a/guix/ui.scm b/guix/ui.scm
index 9e75a35d16..5ca5afe457 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -902,6 +902,8 @@ found."
        (format (current-error-port)
                (_ "guix: unrecognized option '~a'~%") o)
        (show-guix-usage))
+      (("help" args ...)
+       (show-guix-help))
       ((command args ...)
        (apply run-guix-command
               (string->symbol command)