guix package: Gracefully handle EPIPE on '--search'.

* guix/scripts/package.scm (guix-package): Wrap body of 'search' in
  'leave-on-EPIPE'.

config: '%state-directory' always honors $NIX_STATE_DIR.

* guix/config.scm.in (%state-directory): Honor $NIX_STATE_DIR.
* guix/scripts/package.scm (%profile-directory): Use %state-directory
  directly.
* guix/store.scm (%default-socket-path, log-file): Likewise.

archive: Add '--missing'.

* guix/scripts/archive.scm (show-help, %options): Add '--missing'.
  (guix-archive)[lines]: New procedure.
  Use it to honor '--missing'.
* tests/guix-archive.sh: Add tests.
* doc/guix.texi (Invoking guix archive): Document '--missing'.

archive: Make sure $sysconfdir/guix exists.

* guix/pki.scm (ensure-acl): Make sure the directory of %ACL-FILE
  exists.
* guix/scripts/archive.scm (generate-key-pair): Likewise for
  %PUBLIC-KEY-FILE.

guix build: Add '--no-build-hook'.

* guix/scripts/build.scm (%default-options): Add 'build-hook?' pair.
  (show-help, %options): Add --no-build-hook.
  (guix-build): Pass the 'build-hook?' value to 'set-build-options'.
* doc/guix.texi (Invoking guix build): Document '--no-build-hook'.

guix package: Gracefully deal with EPIPE on stdout for --list-*.

* guix/scripts/package.scm (leave-on-EPIPE): New macro.
  (guix-package): Use it for 'list-installed', 'list-available', and
  '--list-generations'.
* tests/guix-package.sh: Add test.

archive: Add '--authorize'.

* guix/scripts/archive.scm (authorize-key): New procedure.
  (guix-archive): Call it when OPTS contains 'authorize-key'.
* tests/guix-archive.sh: Add test with invalid public key.
* guix/pki.scm: Export '%acl-file'.
* doc/guix.texi (Invoking guix archive): Make it clear that '--import'
  works only with authorized keys.  Document '--authorize'.

archive: Add '--generate-key'.

* guix/pk-crypto.scm (error-source, error-string): New procedures.
* guix/pki.scm (%private-key-file): New variable.
* guix/scripts/archive.scm (show-help): Document '--generate-key'.
  (%options): Add "generate-key".
  (generate-key-pair): New procedure.
  (guix-archive): Call 'generate-key' when OPTS contains a
  'generate-key' pair.
* doc/guix.texi (Setting Up the Daemon): Suggest generating a key pair.
  (Invoking guix archive): Document '--generate-key'.

authenticate: Consistently use 'leave' for fatal error reporting.

* guix/scripts/authenticate.scm (guix-authenticate): Replace all uses of
  'format' + 'exit' with 'leave'.

authenticate: Disallow imports signed with unauthorized keys.

* guix/scripts/authenticate.scm (signature-sexp): Remove.
  (guix-authenticate): Upon '-verify', check whether the signature's
  public key passes 'authorized-key?'.

Move 'with-atomic-file-output' to (guix utils).

* guix/scripts/substitute-binary.scm (with-atomic-file-output): Move to...
* guix/utils.scm (with-atomic-file-output): ... here.

authenticate: Store the public key as part of the signature.

* guix/scripts/authenticate.scm (signature-sexp): New procedure.
  (guix-authenticate): Use it to produce the signature.  Adjust
  verification code accordingly.
* tests/store.scm ("import corrupt path"): Adjust test accordingly.

pk-crypto: Rename 'gcry-sexp' to 'canonical-sexp'.

* guix/pk-crypto.scm: Rename procedures, variables, etc. from
  'gcry-sexp' to 'canonical-sexp'.  Add comment with references.
* guix/scripts/authenticate.scm, tests/pk-crypto.scm: Adjust
  accordingly.

Add 'guix archive'.

* guix/scripts/archive.scm, tests/guix-archive.sh: New files.
* Makefile.am (MODULES): Add 'archive.scm'.
  (SH_TESTS): Add 'guix-archive.sh'.
* doc/guix.texi (Invoking guix archive): New section.
* guix/scripts/build.scm: Export 'derivation-from-expression'.
* guix/scripts/package.scm: Export 'specification->package+output'.

guix build: Improve procedural decomposition.

* guix/scripts/build.scm (%store): Remove.
  (derivation-from-expression): Add 'store' parameter.  Adjust caller
  accordingly.
  (register-root): New procedure, formerly within 'guix-build'.
  (options->derivations): New procedure, formerly inline within
  'guix-build'.
  (guix-build): Adjust accordingly.

Factorize package search between 'guix package' and 'guix build'.

* guix/scripts/package.scm (newest-available-packages): Remove.
  (find-best-packages-by-name): Move to...
* gnu/packages.scm (find-best-packages-by-name): ... here.
  (find-newest-available-packages): Memoize.
* guix/scripts/build.scm (specification->package): New procedure,
  formerly called 'find-package' within 'guix-build'.
  (guix-build): Adjust accordingly.

daemon: Implement signed archive import/export.

* guix/scripts/authenticate.scm, nix/scripts/guix-authenticate.in,
  tests/signing-key.pub, tests/signing-key.sec: New files.
* po/POTFILES.in: Add 'guix/scripts/authenticate.scm'.
* guix/store.scm (dump-port): New procedure.
  (process-stderr): Add 'user-port' optional parameter.  Handle
  the %STDERR-WRITE and %STDERR-READ cases as expected.
  (import-paths, export-path, export-paths): New procedures.
* tests/store.scm ("export/import several paths", "import corrupt
  path"): New tests.
* Makefile.am (MODULES): Add 'guix/scripts/authenticate.scm'.
  (EXTRA_DIST): Add 'tests/signing-key.{pub,sec}'.
* daemon.am (libstore_a_CPPFLAGS)[-DNIX_CONF_DIR]: Change 'NIX_CONF_DIR'
  to .../guix.  Change 'OPENSSL_PATH' to 'guix-authenticate'.
* config-daemon.ac: Instantiate 'nix/scripts/guix-authenticate'.
* nix/nix-daemon/guix-daemon.cc (main): Augment $PATH to include
  'settings.nixLibexecDir'.
* test-env.in: Export 'NIX_CONF_DIR' and 'NIX_LIBEXEC_DIR'.  Populate
  $NIX_CONF_DIR.

pull: Move build code to (guix build pull).

* guix/build/pull.scm: New file.
* Makefile.am (MODULES): Add it.
* guix/scripts/pull.scm (unpack): Use it.

guix package: allow multiple arguments after -i, -r, and -u.

* guix/scripts/package.scm (%options): Adapt option processors to accept and
  return a second seed value: 'arg-handler', which handles bare arguments (if
  not false).  The install, remove, and upgrade option processors return an
  arg-handler that repeat the same operation.  All other option processors
  return #f as the arg-handler.  Make the arguments to install and remove
  optional.  The upgrade option processor deletes (upgrade . #f) from the
  alist before adding a new entry.
  (guix-package): Procedures passed to 'args-fold*' accept the new seed value
  'arg-handler'.  The 'operand-proc' uses 'arg-handler' (if not false).

* doc/guix.texi (Invoking guix package): Update docs.

* tests/guix-package.sh: Add test.

pull: Compile guix/ files before gnu/ files.

* guix/scripts/pull.scm (unpack)[builder]: Build files under guix/
  before files under gnu/.