From ccea821befc96a2c5e0c64b1a18eef0f31abe0a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Mon, 10 Nov 2014 18:14:20 +0100
Subject: [PATCH] syscalls: Add 'mount-points'.

* guix/build/syscalls.scm (mount-points): New procedure.
* tests/syscalls.scm ("mount-points"): New test.
---
 guix/build/syscalls.scm | 13 +++++++++++++
 tests/syscalls.scm      |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 7e5245fcc6..9765820836 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -31,6 +31,7 @@
             MS_MOVE
             mount
             umount
+            mount-points
             swapon
             swapoff
             processes
@@ -166,6 +167,18 @@ constants from <sys/mount.h>."
         (when update-mtab?
           (remove-from-mtab target))))))
 
+(define (mount-points)
+  "Return the mounts points for currently mounted file systems."
+  (call-with-input-file "/proc/mounts"
+    (lambda (port)
+      (let loop ((result '()))
+        (let ((line (read-line port)))
+          (if (eof-object? line)
+              (reverse result)
+              (match (string-tokenize line)
+                ((source mount-point _ ...)
+                 (loop (cons mount-point result))))))))))
+
 (define swapon
   (let* ((ptr  (dynamic-func "swapon" (dynamic-link)))
          (proc (pointer->procedure int ptr (list '* int))))
diff --git a/tests/syscalls.scm b/tests/syscalls.scm
index 161e036e19..d65ec82740 100644
--- a/tests/syscalls.scm
+++ b/tests/syscalls.scm
@@ -44,6 +44,9 @@
       ;; Both return values have been encountered in the wild.
       (memv (system-error-errno args) (list EPERM ENOENT)))))
 
+(test-assert "mount-points"
+  (member "/" (mount-points)))
+
 (test-assert "swapon, ENOENT/EPERM"
   (catch 'system-error
     (lambda ()