On 10/04/2012 07:36 PM, Ondrej Oprala wrote:
> Hi, I haven't heard from this thread in a while, are there still things
> to be done here?
Hi Ondrej,
FWIW, I've rebased your patch to Git master.
(The only change I made - besides resolving the conflicts -
was to declare devlist_head static to make syntax-check happy.)
However, that implementation needs further discussion:
* IMO, "df -a" should not skip bind mounts, and instead
print all of the lines.
* It doesn't play well with Robert's suggestion for hiding
the 'rootfs' entry, because dev_examined() already added
the entry for the '/' file system before the rootfs entry is
skipped, which makes the real '/' entry also be skipped.
http://lists.gnu.org/archive/html/coreutils/2012-11/msg00091.html
But also Robert's patch deserves further discussion.
IMO e.g. "df -t rootfs" and again "df -a" should not skip
rootfs. And read_file_system_list must be called with true
param to make it work.
* It still allocates one devlist entry more than needed.
Have a nice day,
Berny
From 7d2c56e52b0a8c2cdc802576b33b2870621b11c5 Mon Sep 17 00:00:00 2001
From: Ondrej Oprala <oopr...@redhat.com>
Date: Thu, 29 Nov 2012 18:21:27 +0100
Subject: [PATCH] df: Fix outputting filesystem duplicities caused by
bind-mounts
* NEWS: Mention the fix.
* src/df.c (devlist_add): Add another entry to the global
device number list.
(dev_examined): Check if a filesystem has been examined already.
* tests/df/df-dup-remove.sh: Add a new test simulating mtab entries.
* tests/local.mk: Add the test to the list.
---
NEWS | 3 ++
src/df.c | 70 +++++++++++++++++++++++++++++++++++++++++++-
tests/df/df-dup-remove.sh | 69 ++++++++++++++++++++++++++++++++++++++++++++
tests/local.mk | 1 +
4 files changed, 141 insertions(+), 2 deletions(-)
create mode 100755 tests/df/df-dup-remove.sh
diff --git a/NEWS b/NEWS
index d4aebeb..d0e13f6 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,9 @@ GNU coreutils NEWS -*-
outline -*-
another range. Before, "echo 123|cut --output-delim=: -b2-,3" would print
"2:3". Now it prints "23". [bug introduced in 5.3.0]
+ df now properly outputs filesystem information with bind mounts
+ present on the system.
+
install -m M SOURCE DEST no longer has a race condition where DEST's
permissions are temporarily derived from SOURCE instead of from M.
diff --git a/src/df.c b/src/df.c
index cac26b7..0a1a691 100644
--- a/src/df.c
+++ b/src/df.c
@@ -43,6 +43,17 @@
proper_name ("David MacKenzie"), \
proper_name ("Paul Eggert")
+/* Filled with device numbers of examined filesystems to avoid
+ duplicities in output. */
+struct devlist
+{
+ dev_t dev_num;
+ struct devlist *dev_next;
+};
+
+/* Device list help pointer. */
+static struct devlist *devlist_head;
+
/* If true, show even file systems with zero size or
uninteresting types. */
static bool show_all_fs;
@@ -1076,6 +1087,48 @@ get_entry (char const *name, struct stat const *statp)
get_point (name, statp);
}
+/* Add a device number of the soon-to-be examined
+ filesystem to the global list devlist. */
+
+static void
+devlist_add (dev_t dev_num)
+{
+ struct devlist *devlist = devlist_head;
+ while (devlist->dev_next)
+ devlist = devlist->dev_next;
+
+ if (!devlist->dev_num)
+ devlist->dev_num = dev_num;
+ else
+ {
+ devlist->dev_next = xmalloc (sizeof *devlist);
+ devlist = devlist->dev_next;
+ devlist->dev_num = dev_num;
+ devlist->dev_next = NULL;
+ }
+}
+
+/* Check if the device was already examined. */
+
+static bool
+dev_examined (struct devlist *devlist, char *mount_dir)
+{
+ dev_t dev_num;
+ struct stat buf;
+ stat (mount_dir, &buf);
+
+ dev_num = buf.st_dev;
+ while (devlist)
+ {
+ if (devlist->dev_num == dev_num)
+ return true;
+ devlist = devlist->dev_next;
+ }
+
+ devlist_add (dev_num);
+ return false;
+}
+
/* Show all mounted file systems, except perhaps those that are of
an unselected type or are empty. */
@@ -1083,10 +1136,23 @@ static void
get_all_entries (void)
{
struct mount_entry *me;
+ struct devlist *devlist = xmalloc (sizeof *devlist);
+ devlist_head = devlist;
+
+ devlist->dev_num = 0;
+ devlist->dev_next = NULL;
for (me = mount_list; me; me = me->me_next)
- get_dev (me->me_devname, me->me_mountdir, NULL, me->me_type,
- me->me_dummy, me->me_remote, NULL, true);
+ if (!dev_examined (devlist, me->me_mountdir))
+ get_dev (me->me_devname, me->me_mountdir, NULL, me->me_type,
+ me->me_dummy, me->me_remote, NULL, true);
+
+ while (devlist)
+ {
+ devlist = devlist->dev_next;
+ free (devlist_head);
+ devlist_head = devlist;
+ }
}
/* Add FSTYPE to the list of file system types to display. */
diff --git a/tests/df/df-dup-remove.sh b/tests/df/df-dup-remove.sh
new file mode 100755
index 0000000..d097d4a
--- /dev/null
+++ b/tests/df/df-dup-remove.sh
@@ -0,0 +1,69 @@
+#!/bin/sh
+# Test df's behaviour when the mount list contains duplicit entries.
+# This test is skipped on systems that lack LD_PRELOAD support; that's fine.
+
+# Copyright (C) 2012 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ df
+
+df || skip_ "df fails"
+
+# Simulate "mtab" failure.
+cat > k.c <<'EOF' || framework_failure_
+#include <stdio.h>
+#include <mntent.h>
+
+struct mntent *getmntent (FILE *fp)
+{
+ /* Prove that LD_PRELOAD works. */
+ static int done = 0;
+ if (!done)
+ {
+ fclose (fopen ("x", "w"));
+ ++done;
+ }
+ /* Now simulate an mtab file with
+ two entries. */
+
+ static struct mntent mntent;
+
+ while (done++ < 3)
+ {
+ mntent.mnt_fsname = "fsname";
+ mntent.mnt_dir = "/";
+ mntent.mnt_type = "-";
+
+ return &mntent;
+ }
+ return NULL;
+}
+EOF
+
+# Then compile/link it:
+gcc --std=gnu99 -shared -fPIC -ldl -O2 k.c -o k.so \
+ || skip_ "getmntent hack does not work on this platform"
+
+# Test if LD_PRELOAD works:
+LD_PRELOAD=./k.so df
+test -f x || skip_ "internal test failure: maybe LD_PRELOAD doesn't work?"
+
+#The fake mtab file should only contain 2 entries, both
+#having the same device number; thus the output should
+#consist of a header and one entry
+test $(LD_PRELOAD=./k.so df | wc -l) -eq 2 || fail=1
+
+Exit $fail
diff --git a/tests/local.mk b/tests/local.mk
index 1b0ace4..8f5def2 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -457,6 +457,7 @@ all_tests = \
tests/df/unreadable.sh \
tests/df/total-unprocessed.sh \
tests/df/no-mtab-status.sh \
+ tests/df/df-dup-remove.sh \
tests/dd/direct.sh \
tests/dd/misc.sh \
tests/dd/nocache.sh \
--
1.7.7
