From c21d912a027056c30ee86c1ce021322e89f474c3 Mon Sep 17 00:00:00 2001 From: Ludovic Courtès Date: Mon, 29 Apr 2019 21:39:38 +0200 Subject: processes: 'process-open-files' ignores disappeared /proc/PID/fd entries. Previously, 'process-open-files' would throw ENOENT if an entry had vanished after the 'scandir' call and before the 'readlink' call. * guix/scripts/processes.scm (process-open-files): Catch ENOENT errors from 'readlink'. --- guix/scripts/processes.scm | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/guix/scripts/processes.scm b/guix/scripts/processes.scm index 6a2f603599..2dd3bbf30a 100644 --- a/guix/scripts/processes.scm +++ b/guix/scripts/processes.scm @@ -1,5 +1,5 @@ ;;; GNU Guix --- Functional package management for GNU -;;; Copyright © 2018 Ludovic Courtès +;;; Copyright © 2018, 2019 Ludovic Courtès ;;; ;;; This file is part of GNU Guix. ;;; @@ -103,9 +103,16 @@ processes." (let ((directory (string-append "/proc/" (number->string (process-id process)) "/fd"))) - (map (lambda (fd) - (readlink (string-append directory "/" fd))) - (or (scandir directory string->number) '())))) + (filter-map (lambda (fd) + ;; There's a TOCTTOU race here, hence the 'catch'. + (catch 'system-error + (lambda () + (readlink (string-append directory "/" fd))) + (lambda args + (if (= ENOENT (system-error-errno args)) + #f + (apply throw args))))) + (or (scandir directory string->number) '())))) ;; Daemon session. (define-record-type -- cgit v1.2.3