grafts: Add (guix build debug-link) and use it.

Fixes <https://bugs.gnu.org/19973>.
Reported by Mark H Weaver <mhw@netris.org>.

* guix/build/debug-link.scm: New file.
* guix/build/graft.scm (%graft-hooks): New variable.
(graft): Add #:hooks and honor it.
* guix/grafts.scm (graft-derivation/shallow): Add (guix build
debug-link) and (guix elf) to #:modules.
* tests/debug-link.scm: New file.
* Makefile.am (MODULES): Add guix/build/debug-link.scm.
(SCM_TESTS): Add tests/debug-link.scm.

1 files changed, 158 insertions, 0 deletions

diff --git a/tests/debug-link.scm b/tests/debug-link.scm
new file mode 100644
index 00000000000..2dde3cb4607
--- /dev/null
+++ b/tests/debug-link.scm
@@ -0,0 +1,158 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2018 Ludovic Courtès <ludo@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 (test-debug-link)
+  #:use-module (guix elf)
+  #:use-module (guix build utils)
+  #:use-module (guix build debug-link)
+  #:use-module (guix gexp)
+  #:use-module (guix store)
+  #:use-module (guix tests)
+  #:use-module (guix monads)
+  #:use-module (guix derivations)
+  #:use-module (gnu packages bootstrap)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-64)
+  #:use-module (rnrs io ports)
+  #:use-module (ice-9 match))
+
+(define %guile-executable
+  (match (false-if-exception (readlink "/proc/self/exe"))
+    ((? string? program)
+     (and (file-exists? program) (elf-file? program)
+          program))
+    (_
+     #f)))
+
+(define read-elf
+  (compose parse-elf get-bytevector-all))
+
+(define %store
+  (open-connection-for-tests))
+
+(define-syntax-rule (test-assertm name exp)
+  (test-assert name
+    (run-with-store %store exp
+                    #:guile-for-build (%guile-for-build))))
+
+
+(test-begin "debug-link")
+
+(unless %guile-executable (test-skip 1))
+(test-assert "elf-debuglink"
+  (let ((elf (call-with-input-file %guile-executable read-elf)))
+    (match (call-with-values (lambda () (elf-debuglink elf)) list)
+      ((#f #f)                                    ;no '.gnu_debuglink' section
+       (pk 'no-debuglink #t))
+      (((? string? file) (? integer? crc))
+       (string-suffix? ".debug" file)))))
+
+;; Since we need %BOOTSTRAP-GCC and co., we have to skip the following tests
+;; when networking is unreachable because we'd fail to download it.
+(unless (network-reachable?) (test-skip 1))
+(test-assertm "elf-debuglink"
+  ;; Check whether we can compute the CRC just like objcopy, and whether we
+  ;; can retrieve it.
+  (let* ((code (plain-file "test.c" "int main () { return 42; }"))
+         (exp  (with-imported-modules '((guix build utils)
+                                        (guix build debug-link)
+                                        (guix elf))
+                 #~(begin
+                     (use-modules (guix build utils)
+                                  (guix build debug-link)
+                                  (guix elf)
+                                  (rnrs io ports))
+
+                     (define read-elf
+                       (compose parse-elf get-bytevector-all))
+
+                     (setenv "PATH" (string-join '(#$%bootstrap-gcc
+                                                   #$%bootstrap-binutils)
+                                                 "/bin:" 'suffix))
+                     (invoke "gcc" "-O0" "-g" #$code "-o" "exe")
+                     (copy-file "exe" "exe.debug")
+                     (invoke "strip" "--only-keep-debug" "exe.debug")
+                     (invoke "strip" "--strip-debug" "exe")
+                     (invoke "objcopy" "--add-gnu-debuglink=exe.debug"
+                             "exe")
+                     (call-with-values (lambda ()
+                                         (elf-debuglink
+                                          (call-with-input-file "exe"
+                                            read-elf)))
+                       (lambda (file crc)
+                         (call-with-output-file #$output
+                           (lambda (port)
+                             (let ((expected (call-with-input-file "exe.debug"
+                                               debuglink-crc32)))
+                               (write (list file (= crc expected))
+                                      port))))))))))
+    (mlet* %store-monad ((drv (gexp->derivation "debuglink" exp))
+                         (x   (built-derivations (list drv))))
+      (call-with-input-file (derivation->output-path drv)
+        (lambda (port)
+          (return (match (read port)
+                    (("exe.debug" #t) #t)
+                    (x                (pk 'fail x #f)))))))))
+
+(unless (network-reachable?) (test-skip 1))
+(test-assertm "set-debuglink-crc"
+  ;; Check whether 'set-debuglink-crc' successfully updates the CRC.
+  (let* ((code  (plain-file "test.c" "int main () { return 42; }"))
+         (debug (plain-file "exe.debug" "a"))
+         (exp   (with-imported-modules '((guix build utils)
+                                         (guix build debug-link)
+                                         (guix elf))
+                  #~(begin
+                      (use-modules (guix build utils)
+                                   (guix build debug-link)
+                                   (guix elf)
+                                   (rnrs io ports))
+
+                      (define read-elf
+                        (compose parse-elf get-bytevector-all))
+
+                      (setenv "PATH" (string-join '(#$%bootstrap-gcc
+                                                    #$%bootstrap-binutils)
+                                                  "/bin:" 'suffix))
+                      (invoke "gcc" "-O0" "-g" #$code "-o" "exe")
+                      (copy-file "exe" "exe.debug")
+                      (invoke "strip" "--only-keep-debug" "exe.debug")
+                      (invoke "strip" "--strip-debug" "exe")
+                      (invoke "objcopy" "--add-gnu-debuglink=exe.debug"
+                              "exe")
+                      (set-debuglink-crc "exe" #$debug)
+                      (call-with-values (lambda ()
+                                          (elf-debuglink
+                                           (call-with-input-file "exe"
+                                             read-elf)))
+                        (lambda (file crc)
+                          (call-with-output-file #$output
+                            (lambda (port)
+                              (write (list file crc) port)))))))))
+    (mlet* %store-monad ((drv (gexp->derivation "debuglink" exp))
+                         (x   (built-derivations (list drv))))
+      (call-with-input-file (derivation->output-path drv)
+        (lambda (port)
+          (return (match (read port)
+                    (("exe.debug" crc)
+                     (= crc (debuglink-crc32 (open-input-string "a"))))
+                    (x
+                     (pk 'fail x #f)))))))))
+
+(test-end "debug-link")