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| author | Ludovic Courtès <ludo@gnu.org> | 2023-01-30 22:20:18 +0100 |
|---|---|---|
| committer | Ludovic Courtès <ludo@gnu.org> | 2023-01-30 22:24:27 +0100 |
| commit | 0ef8fe22ed8985c9656835fc25ab3463d55b6669 (patch) | |
| tree | 87f453456f8d29da3c4eca9f8f495e17ce9a3d97 | |
| parent | 52eb3db19cb9e5c294c86a8552a4baaa5b473672 (diff) | |
linux-container: 'container-excursion' forks to join the PID namespace.
Fixes <https://issues.guix.gnu.org/61156>.
* gnu/build/linux-container.scm (container-excursion): Add extra call to
'primitive-fork' and invoke THUNK in the child process.
* tests/containers.scm ("container-excursion"): Remove extra
'primitive-fork' call, now unnecessary.
("container-excursion*, /proc"): New test.
| -rw-r--r-- | gnu/build/linux-container.scm | 13 | ||||
| -rw-r--r-- | tests/containers.scm | 46 |
2 files changed, 40 insertions, 19 deletions
diff --git a/gnu/build/linux-container.scm b/gnu/build/linux-container.scm index d11c49c0d8..dee6885400 100644 --- a/gnu/build/linux-container.scm +++ b/gnu/build/linux-container.scm @@ -1,6 +1,6 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2015 David Thompson <davet@gnu.org> -;;; Copyright © 2017-2019, 2022 Ludovic Courtès <ludo@gnu.org> +;;; Copyright © 2017-2019, 2022, 2023 Ludovic Courtès <ludo@gnu.org> ;;; ;;; This file is part of GNU Guix. ;;; @@ -432,7 +432,16 @@ return the exit status, an integer as returned by 'waitpid'." '("user" "ipc" "uts" "net" "pid" "mnt")) (purify-environment) (chdir "/") - (thunk)))) + + ;; Per setns(2), changing the PID namespace only applies to child + ;; processes, not to the process itself. Thus fork so that THUNK runs + ;; in the right PID namespace, which also gives it access to /proc. + (match (primitive-fork) + (0 (call-with-clean-exit thunk)) + (pid (primitive-exit + (match (waitpid pid) + ((_ . status) + (or (status:exit-val status) 127))))))))) (pid (match (waitpid pid) ((_ . status) diff --git a/tests/containers.scm b/tests/containers.scm index 1378b10f22..70d5ba2d30 100644 --- a/tests/containers.scm +++ b/tests/containers.scm @@ -1,6 +1,6 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2015 David Thompson <davet@gnu.org> -;;; Copyright © 2016, 2017, 2019 Ludovic Courtès <ludo@gnu.org> +;;; Copyright © 2016, 2017, 2019, 2023 Ludovic Courtès <ludo@gnu.org> ;;; ;;; This file is part of GNU Guix. ;;; @@ -31,7 +31,8 @@ #:use-module (guix tests) #:use-module (srfi srfi-1) #:use-module (srfi srfi-64) - #:use-module (ice-9 match)) + #:use-module (ice-9 match) + #:use-module ((ice-9 ftw) #:select (scandir))) (define (assert-exit x) (primitive-exit (if x 0 1))) @@ -176,21 +177,11 @@ (close start-in) (container-excursion pid (lambda () - ;; Fork again so that the pid is within the context of - ;; the joined pid namespace instead of the original pid - ;; namespace. - (match (primitive-fork) - (0 - ;; Check that all of the namespace identifiers are - ;; the same as the container process. - (assert-exit - (equal? container-namespaces - (namespaces (getpid))))) - (fork-pid - (match (waitpid fork-pid) - ((_ . status) - (primitive-exit - (status:exit-val status))))))))))) + ;; Check that all of the namespace identifiers are + ;; the same as the container process. + (assert-exit + (equal? container-namespaces + (namespaces (getpid))))))))) (close end-in) ;; Stop the container. (write 'done end-out) @@ -237,6 +228,27 @@ (* 6 7)))) (skip-if-unsupported) +(test-equal "container-excursion*, /proc" + '("1" "2") + (call-with-temporary-directory + (lambda (root) + (let* ((pid (run-container root '() + %namespaces 1 + (lambda () + (sleep 100)))) + (result (container-excursion* pid + (lambda () + ;; We expect to see exactly two processes in this + ;; namespace. + (scandir "/proc" + (lambda (file) + (char-set-contains? + char-set:digit + (string-ref file 0)))))))) + (kill pid SIGKILL) + result)))) + +(skip-if-unsupported) (test-equal "eval/container, exit status" 42 (let* ((store (open-connection-for-tests)) |