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authorLudovic Courtès <ludo@gnu.org>2017-11-12 22:02:22 +0100
committerLudovic Courtès <ludo@gnu.org>2017-11-12 22:42:17 +0100
commitb8f59cdc20e9d83ce63523ef917e95fcee07f134 (patch)
tree15ebea7f4b9c0c170f68760ed9e2807cd6863e9e /nix
parent6a98b9f34e6190a2e1d11bedd5853aa94cf25ca7 (diff)
downloadpatches-b8f59cdc20e9d83ce63523ef917e95fcee07f134.tar
patches-b8f59cdc20e9d83ce63523ef917e95fcee07f134.tar.gz
list-runtime-roots: Do not use 'lsof'.
This makes things a bit faster (0.8s instead of 1.4s on my laptop). * nix/scripts/list-runtime-roots.in (lsof-roots): Remove. (proc-fd-roots): Return the empty list when 'scandir' returns #f. (referenced-files): New procedure. Use it at the top level.
Diffstat (limited to 'nix')
-rw-r--r--nix/scripts/list-runtime-roots.in79
1 files changed, 21 insertions, 58 deletions
diff --git a/nix/scripts/list-runtime-roots.in b/nix/scripts/list-runtime-roots.in
index a6938087b5..6f0e7f5b6a 100644
--- a/nix/scripts/list-runtime-roots.in
+++ b/nix/scripts/list-runtime-roots.in
@@ -26,7 +26,6 @@
(use-modules (ice-9 ftw)
(ice-9 regex)
(ice-9 rdelim)
- (ice-9 popen)
(srfi srfi-1)
(srfi srfi-26)
(rnrs io ports))
@@ -59,7 +58,7 @@ or the empty list."
(and target
(string-prefix? "/" target)
target)))
- (scandir dir string->number))))
+ (or (scandir dir string->number) '()))))
(define (proc-maps-roots dir)
"Return the list of store files referenced by DIR, which is a
@@ -107,61 +106,25 @@ or the empty list."
(call-with-input-file environ
get-string-all))))
-(define (lsof-roots)
- "Return the list of roots as found by calling `lsof'."
- (define parent (getpid))
-
- (catch 'system-error
- (lambda ()
- (let ((pipe (catch 'system-error
+(define (referenced-files)
+ "Return the list of referenced store items."
+ (append-map (lambda (pid)
+ (let ((proc (string-append %proc-directory "/" pid)))
+ (catch 'system-error
(lambda ()
- (open-pipe* OPEN_READ "lsof" "-n" "-w" "-F" "n"))
+ (append (proc-exe-roots proc)
+ (proc-cwd-roots proc)
+ (proc-fd-roots proc)
+ (proc-maps-roots proc)
+ (proc-environ-roots proc)))
(lambda args
- ;; In Guile 2.0.5, when (ice-9 popen) was still written
- ;; in Scheme, 'open-pipe*' would leave the child process
- ;; behind it when 'execlp' failed (that was mostly
- ;; harmless though, because the uncaught exception would
- ;; cause it to terminate after printing a backtrace.)
- ;; Make sure that doesn't happen.
- (if (= (getpid) parent)
- (apply throw args)
- (begin
- (format (current-error-port)
- "failed to execute 'lsof': ~a~%"
- (strerror (system-error-errno args)))
- (primitive-exit 1)))))))
- (define %file-rx
- (make-regexp "^n/(.*)$"))
-
- ;; We're going to read it all.
- (setvbuf pipe _IOFBF 16384)
-
- (let loop ((line (read-line pipe))
- (roots '()))
- (cond ((eof-object? line)
- (begin
- (close-pipe pipe)
- roots))
- ((regexp-exec %file-rx line)
- =>
- (lambda (match)
- (loop (read-line pipe)
- (cons (string-append "/"
- (match:substring match 1))
- roots))))
- (else
- (loop (read-line pipe) roots))))))
- (lambda _
- '())))
-
-(let ((proc (format #f "~a/~a" %proc-directory (getpid))))
- (for-each (cut simple-format #t "~a~%" <>)
- (delete-duplicates
- (let ((proc-roots (if (file-exists? proc)
- (append (proc-exe-roots proc)
- (proc-cwd-roots proc)
- (proc-fd-roots proc)
- (proc-maps-roots proc)
- (proc-environ-roots proc))
- '())))
- (append proc-roots (lsof-roots))))))
+ ;; There's a TOCTTOU race that we need to handle.
+ (if (= ENOENT (system-error-errno args))
+ '()
+ (apply throw args))))))
+ (scandir %proc-directory string->number
+ (lambda (a b)
+ (< (string->number a) (string->number b))))))
+
+(for-each (cut simple-format #t "~a~%" <>)
+ (delete-duplicates (referenced-files)))