diff options
Diffstat (limited to 'guix/scripts/environment.scm')
| -rw-r--r-- | guix/scripts/environment.scm | 382 |
1 files changed, 314 insertions, 68 deletions
diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm index 2408420e18..2cc5f366a7 100644 --- a/guix/scripts/environment.scm +++ b/guix/scripts/environment.scm @@ -25,13 +25,19 @@ #:use-module (guix profiles) #:use-module (guix search-paths) #:use-module (guix utils) + #:use-module (guix build utils) #:use-module (guix monads) #:use-module ((guix gexp) #:select (lower-inputs)) #:use-module (guix scripts) #:use-module (guix scripts build) + #:use-module (gnu build linux-container) + #:use-module (gnu system linux-container) + #:use-module (gnu system file-systems) #:use-module (gnu packages) + #:use-module (gnu packages bash) #:use-module (ice-9 format) #:use-module (ice-9 match) + #:use-module (ice-9 rdelim) #:use-module (srfi srfi-1) #:use-module (srfi srfi-11) #:use-module (srfi srfi-26) @@ -60,6 +66,12 @@ OUTPUT) tuples." (define %default-shell (or (getenv "SHELL") "/bin/sh")) +(define %network-configuration-files + '("/etc/resolv.conf" + "/etc/nsswitch.conf" + "/etc/services" + "/etc/hosts")) + (define (purify-environment) "Unset almost all environment variables. A small number of variables such as 'HOME' and 'USER' are left untouched." @@ -124,6 +136,18 @@ COMMAND or an interactive shell in that environment.\n")) --search-paths display needed environment variable definitions")) (display (_ " -s, --system=SYSTEM attempt to build for SYSTEM--e.g., \"i686-linux\"")) + (display (_ " + -C, --container run command within an isolated container")) + (display (_ " + -N, --network allow containers to access the network")) + (display (_ " + --share=SPEC for containers, share writable host file system + according to SPEC")) + (display (_ " + --expose=SPEC for containers, expose read-only host file system + according to SPEC")) + (display (_ " + --bootstrap use bootstrap binaries to build the environment")) (newline) (show-build-options-help) (newline) @@ -136,12 +160,21 @@ COMMAND or an interactive shell in that environment.\n")) (define %default-options ;; Default to opening a new shell. - `((exec . (,%default-shell)) - (system . ,(%current-system)) + `((system . ,(%current-system)) (substitutes? . #t) (max-silent-time . 3600) (verbosity . 0))) +(define (tag-package-arg opts arg) + "Return a two-element list with the form (TAG ARG) that tags ARG with either +'ad-hoc' in OPTS has the 'ad-hoc?' key set to #t, or 'inputs' otherwise." + ;; Normally, the transitive inputs to a package are added to an environment, + ;; but the ad-hoc? flag changes the meaning of a package argument such that + ;; the package itself is added to the environment instead. + (if (assoc-ref opts 'ad-hoc?) + `(ad-hoc-package ,arg) + `(package ,arg))) + (define %options ;; Specification of the command-line options. (cons* (option '(#\h "help") #f #f @@ -162,10 +195,14 @@ COMMAND or an interactive shell in that environment.\n")) (alist-cons 'search-paths #t result))) (option '(#\l "load") #t #f (lambda (opt name arg result) - (alist-cons 'load arg result))) + (alist-cons 'load + (tag-package-arg result arg) + result))) (option '(#\e "expression") #t #f (lambda (opt name arg result) - (alist-cons 'expression arg result))) + (alist-cons 'expression + (tag-package-arg result arg) + result))) (option '("ad-hoc") #f #f (lambda (opt name arg result) (alist-cons 'ad-hoc? #t result))) @@ -176,6 +213,25 @@ COMMAND or an interactive shell in that environment.\n")) (lambda (opt name arg result) (alist-cons 'system arg (alist-delete 'system result eq?)))) + (option '(#\C "container") #f #f + (lambda (opt name arg result) + (alist-cons 'container? #t result))) + (option '(#\N "network") #f #f + (lambda (opt name arg result) + (alist-cons 'network? #t result))) + (option '("share") #t #f + (lambda (opt name arg result) + (alist-cons 'file-system-mapping + (specification->file-system-mapping arg #t) + result))) + (option '("expose") #t #f + (lambda (opt name arg result) + (alist-cons 'file-system-mapping + (specification->file-system-mapping arg #f) + result))) + (option '("bootstrap") #f #f + (lambda (opt name arg result) + (alist-cons 'bootstrap? #t result))) %standard-build-options)) (define (pick-all alist key) @@ -189,29 +245,40 @@ COMMAND or an interactive shell in that environment.\n")) (_ memo))) '() alist)) +(define (compact lst) + "Remove all #f elements from LST." + (filter identity lst)) + (define (options/resolve-packages opts) "Return OPTS with package specification strings replaced by actual packages." - (append-map (match-lambda - (('package . (? string? spec)) - (let-values (((package output) - (specification->package+output spec))) - `((package ,package ,output)))) - (('expression . str) - ;; Add all the outputs of the package STR evaluates to. - (match (read/eval str) - ((? package? package) - (map (lambda (output) - `(package ,package ,output)) - (package-outputs package))))) - (('load . file) - ;; Add all the outputs of the package defined in FILE. - (let ((package (load* file (make-user-module '())))) - (map (lambda (output) - `(package ,package ,output)) - (package-outputs package)))) - (opt (list opt))) - opts)) + (define (package->outputs package mode) + (map (lambda (output) + (list mode package output)) + (package-outputs package))) + + (define (packages->outputs packages mode) + (match packages + ((? package? package) + (package->outputs package mode)) + (((? package? packages) ...) + (append-map (cut package->outputs <> mode) packages)))) + + (compact + (append-map (match-lambda + (('package mode (? string? spec)) + (let-values (((package output) + (specification->package+output spec))) + (list (list mode package output)))) + (('expression mode str) + ;; Add all the outputs of the package STR evaluates to. + (packages->outputs (read/eval str) mode)) + (('load mode file) + ;; Add all the outputs of the package defined in FILE. + (let ((module (make-user-module '()))) + (packages->outputs (load* file module) mode))) + (_ '(#f))) + opts))) (define (build-inputs inputs opts) "Build the derivations in INPUTS, a list of (DERIVATION) or (DERIVATION @@ -227,14 +294,145 @@ OUTPUT) tuples, using the build options in OPTS." (if dry-run? (return #f) (mbegin %store-monad - (set-build-options-from-command-line* opts) (built-derivations derivations) (return derivations)))))))) +(define requisites* (store-lift requisites)) + +(define (inputs->requisites inputs) + "Convert INPUTS, a list of input tuples or store path strings, into a set of +requisite store items i.e. the union closure of all the inputs." + (define (input->requisites input) + (requisites* + (match input + ((drv output) + (derivation->output-path drv output)) + ((drv) + (derivation->output-path drv)) + ((? direct-store-path? path) + path)))) + + (mlet %store-monad ((reqs (sequence %store-monad + (map input->requisites inputs)))) + (return (delete-duplicates (concatenate reqs))))) + +(define (status->exit-code status) + "Compute the exit code made from STATUS, a value as returned by 'waitpid', +and suitable for 'exit'." + ;; See <bits/waitstatus.h>. + (or (status:exit-val status) + (logior #x80 (status:term-sig status)))) + +(define exit/status (compose exit status->exit-code)) +(define primitive-exit/status (compose primitive-exit status->exit-code)) + +(define (launch-environment command inputs paths pure?) + "Run COMMAND in a new environment containing INPUTS, using the native search +paths defined by the list PATHS. When PURE?, pre-existing environment +variables are cleared before setting the new ones." + (create-environment inputs paths pure?) + (apply system* command)) + +(define* (launch-environment/container #:key command bash user-mappings + inputs paths network?) + "Run COMMAND within a Linux container. The environment features INPUTS, a +list of derivations to be shared from the host system. Environment variables +are set according to PATHS, a list of native search paths. The global shell +is BASH, a file name for a GNU Bash binary in the store. When NETWORK?, +access to the host system network is permitted. USER-MAPPINGS, a list of file +system mappings, contains the user-specified host file systems to mount inside +the container." + (mlet %store-monad ((reqs (inputs->requisites + (cons (direct-store-path bash) inputs)))) + (return + (let* ((cwd (getcwd)) + ;; Bind-mount all requisite store items, user-specified mappings, + ;; /bin/sh, the current working directory, and possibly networking + ;; configuration files within the container. + (mappings + (append user-mappings + ;; Current working directory. + (list (file-system-mapping + (source cwd) + (target cwd) + (writable? #t))) + ;; When in Rome, do as Nix build.cc does: Automagically + ;; map common network configuration files. + (if network? + (filter-map (lambda (file) + (and (file-exists? file) + (file-system-mapping + (source file) + (target file) + (writable? #f)))) + %network-configuration-files) + '()) + ;; Mappings for the union closure of all inputs. + (map (lambda (dir) + (file-system-mapping + (source dir) + (target dir) + (writable? #f))) + reqs))) + (file-systems (append %container-file-systems + (map mapping->file-system mappings)))) + (exit/status + (call-with-container (map file-system->spec file-systems) + (lambda () + ;; Setup global shell. + (mkdir-p "/bin") + (symlink bash "/bin/sh") + + ;; Setup directory for temporary files. + (mkdir-p "/tmp") + (for-each (lambda (var) + (setenv var "/tmp")) + ;; The same variables as in Nix's 'build.cc'. + '("TMPDIR" "TEMPDIR" "TMP" "TEMP")) + + ;; From Nix build.cc: + ;; + ;; Set HOME to a non-existing path to prevent certain + ;; programs from using /etc/passwd (or NIS, or whatever) + ;; to locate the home directory (for example, wget looks + ;; for ~/.wgetrc). I.e., these tools use /etc/passwd if + ;; HOME is not set, but they will just assume that the + ;; settings file they are looking for does not exist if + ;; HOME is set but points to some non-existing path. + (setenv "HOME" "/homeless-shelter") + + ;; For convenience, start in the user's current working + ;; directory rather than the root directory. + (chdir cwd) + + (primitive-exit/status + ;; A container's environment is already purified, so no need to + ;; request it be purified again. + (launch-environment command inputs paths #f))) + #:namespaces (if network? + (delq 'net %namespaces) ; share host network + %namespaces))))))) + +(define (environment-bash container? bootstrap? system) + "Return a monadic value in the store monad for the version of GNU Bash +needed in the environment for SYSTEM, if any. If CONTAINER? is #f, return #f. +If CONTAINER? and BOOTSTRAP?, return the store path for the bootstrap Bash. +Otherwise, return the derivation for the Bash package." + (with-monad %store-monad + (cond + ((and container? (not bootstrap?)) + (package->derivation bash)) + ;; Use the bootstrap Bash instead. + ((and container? bootstrap?) + (interned-file + (search-bootstrap-binary "bash" system))) + (else + (return #f))))) + (define (parse-args args) "Parse the list of command line arguments ARGS." (define (handle-argument arg result) - (alist-cons 'package arg result)) + (alist-cons 'package (tag-package-arg result arg) result)) ;; The '--' token is used to separate the command to run from the rest of ;; the operands. @@ -245,55 +443,103 @@ OUTPUT) tuples, using the build options in OPTS." opts (alist-cons 'exec command opts))))) +(define (assert-container-features) + "Check if containers can be created and exit with an informative error +message if any test fails." + (unless (user-namespace-supported?) + (report-error (_ "cannot create container: user namespaces unavailable\n")) + (leave (_ "is your kernel version < 3.10?\n"))) + + (unless (unprivileged-user-namespace-supported?) + (report-error (_ "cannot create container: unprivileged user cannot create user namespaces\n")) + (leave (_ "please set /proc/sys/kernel/unprivileged_userns_clone to \"1\"\n"))) + + (unless (setgroups-supported?) + (report-error (_ "cannot create container: /proc/self/setgroups does not exist\n")) + (leave (_ "is your kernel version < 3.19?\n")))) + ;; Entry point. (define (guix-environment . args) (with-error-handling - (let* ((opts (parse-args args)) - (pure? (assoc-ref opts 'pure)) - (ad-hoc? (assoc-ref opts 'ad-hoc?)) - (command (assoc-ref opts 'exec)) - (packages (pick-all (options/resolve-packages opts) 'package)) - (inputs (if ad-hoc? - (append-map (match-lambda - ((package output) - (package+propagated-inputs package - output))) - packages) - (append-map (compose bag-transitive-inputs - package->bag - first) - packages))) - (paths (delete-duplicates - (cons $PATH - (append-map (match-lambda - ((label (? package? p) _ ...) - (package-native-search-paths p)) - (_ - '())) - inputs)) - eq?))) + (let* ((opts (parse-args args)) + (pure? (assoc-ref opts 'pure)) + (container? (assoc-ref opts 'container?)) + (network? (assoc-ref opts 'network?)) + (bootstrap? (assoc-ref opts 'bootstrap?)) + (system (assoc-ref opts 'system)) + (command (or (assoc-ref opts 'exec) + ;; Spawn a shell if the user didn't specify + ;; anything in particular. + (if container? + ;; The user's shell is likely not available + ;; within the container. + '("/bin/sh") + (list %default-shell)))) + (packages (options/resolve-packages opts)) + (mappings (pick-all opts 'file-system-mapping)) + (inputs (delete-duplicates + (append-map (match-lambda + (('ad-hoc-package package output) + (package+propagated-inputs package + output)) + (('package package output) + (bag-transitive-inputs + (package->bag package)))) + packages))) + (paths (delete-duplicates + (cons $PATH + (append-map (match-lambda + ((label (? package? p) _ ...) + (package-native-search-paths p)) + (_ + '())) + inputs)) + eq?))) + + (when container? (assert-container-features)) + (with-store store + (set-build-options-from-command-line store opts) (run-with-store store - (mlet %store-monad ((inputs (lower-inputs - (map (match-lambda + (mlet* %store-monad ((inputs (lower-inputs + (map (match-lambda ((label item) (list item)) ((label item output) (list item output))) - inputs) - #:system (assoc-ref opts 'system)))) + inputs) + #:system system)) + ;; Containers need a Bourne shell at /bin/sh. + (bash (environment-bash container? + bootstrap? + system))) (mbegin %store-monad - ;; First build INPUTS. This is necessary even for - ;; --search-paths. - (build-inputs inputs opts) - (cond ((assoc-ref opts 'dry-run?) - (return #t)) - ((assoc-ref opts 'search-paths) - (show-search-paths inputs paths pure?) - (return #t)) - (else - (create-environment inputs paths pure?) - (return - (exit - (status:exit-val - (apply system* command))))))))))))) + ;; First build the inputs. This is necessary even for + ;; --search-paths. Additionally, we might need to build bash + ;; for a container. + (build-inputs (if (derivation? bash) + `((,bash "out") ,@inputs) + inputs) + opts) + (cond + ((assoc-ref opts 'dry-run?) + (return #t)) + ((assoc-ref opts 'search-paths) + (show-search-paths inputs paths pure?) + (return #t)) + (container? + (let ((bash-binary + (if bootstrap? + bash + (string-append (derivation->output-path bash) + "/bin/sh")))) + (launch-environment/container #:command command + #:bash bash-binary + #:user-mappings mappings + #:inputs inputs + #:paths paths + #:network? network?))) + (else + (return + (exit/status + (launch-environment command inputs paths pure?)))))))))))) |