1#!/bin/sh
2# Test df's behavior when the mount list contains duplicate entries.
3# This test is skipped on systems that lack LD_PRELOAD support; that's fine.
4
5# Copyright (C) 2012-2023 Free Software Foundation, Inc.
6
7# This program is free software: you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11
12# This program is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16
17# You should have received a copy of the GNU General Public License
18# along with this program.  If not, see <https://www.gnu.org/licenses/>.
19
20. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
21print_ver_ df
22require_gcc_shared_
23
24# We use --local here so as to not activate
25# potentially very many remote mounts.
26df --local --output=target >LOCAL_FS || skip_ 'df fails'
27grep '^/$' LOCAL_FS || skip_ 'no root file system found'
28
29# Get real targets to substitute for /NONROOT and /REMOTE below.
30export CU_NONROOT_FS=$(grep /. LOCAL_FS | head -n1)
31export CU_REMOTE_FS=$(grep /. LOCAL_FS | tail -n+2 | head -n1)
32
33unique_entries=1
34test -z "$CU_NONROOT_FS" || unique_entries=$(expr $unique_entries + 1)
35test -z "$CU_REMOTE_FS" || unique_entries=$(expr $unique_entries + 2)
36
37grep '^#define HAVE_MNTENT_H 1' $CONFIG_HEADER > /dev/null \
38      || skip_ "no mntent.h available to confirm the interface"
39
40grep '^#define HAVE_GETMNTENT 1' $CONFIG_HEADER > /dev/null \
41      || skip_ "getmntent is not used on this system"
42
43# Simulate an mtab file to test various cases.
44cat > k.c <<EOF || framework_failure_
45#define _GNU_SOURCE
46#include <stdio.h>
47#include <stdlib.h>
48#include <errno.h>
49#include <mntent.h>
50#include <string.h>
51#include <dlfcn.h>
52
53#define STREQ(a, b) (strcmp (a, b) == 0)
54
55FILE* fopen(const char *path, const char *mode)
56{
57  static FILE* (*fopen_func)(char const *, char const *);
58
59  /* get reference to original (libc provided) fopen */
60  if (!fopen_func)
61    {
62      fopen_func = (FILE*(*)(char const *, char const *))
63                   dlsym(RTLD_NEXT, "fopen");
64      if (!fopen_func)
65        {
66          fprintf (stderr, "Failed to find fopen()\n");
67          errno = ESRCH;
68          return NULL;
69        }
70    }
71
72  /* Returning ENOENT here will get read_file_system_list()
73     to fall back to using getmntent() below.  */
74  if (STREQ (path, "/proc/self/mountinfo"))
75    {
76      errno = ENOENT;
77      return NULL;
78    }
79  else
80    return fopen_func(path, mode);
81}
82
83#define STREQ(a, b) (strcmp (a, b) == 0)
84
85struct mntent *getmntent (FILE *fp)
86{
87  static char *nonroot_fs;
88  static char *remote_fs;
89  static int done;
90
91  /* Prove that LD_PRELOAD works. */
92  if (!done)
93    {
94      fclose (fopen ("x", "w"));
95      ++done;
96    }
97
98  static struct mntent mntents[] = {
99    {.mnt_fsname="/short",  .mnt_dir="/invalid/mount/dir",       .mnt_opts=""},
100    {.mnt_fsname="fsname",  .mnt_dir="/",                        .mnt_opts=""},
101    {.mnt_fsname="/fsname", .mnt_dir="/.",                       .mnt_opts=""},
102    {.mnt_fsname="/fsname", .mnt_dir="/",                        .mnt_opts=""},
103    {.mnt_fsname="virtfs",  .mnt_dir="/NONROOT", .mnt_type="t1", .mnt_opts=""},
104    {.mnt_fsname="virtfs2", .mnt_dir="/NONROOT", .mnt_type="t2", .mnt_opts=""},
105    {.mnt_fsname="netns",   .mnt_dir="net:[1234567]",            .mnt_opts=""},
106    {.mnt_fsname="rem:ote1",.mnt_dir="/REMOTE",                  .mnt_opts=""},
107    {.mnt_fsname="rem:ote1",.mnt_dir="/REMOTE",                  .mnt_opts=""},
108    {.mnt_fsname="rem:ote2",.mnt_dir="/REMOTE",                  .mnt_opts=""},
109  };
110
111  if (done == 1)
112    {
113      nonroot_fs = getenv ("CU_NONROOT_FS");
114      if (!nonroot_fs || !*nonroot_fs)
115        nonroot_fs = "/"; /* merge into / entries.  */
116
117      remote_fs = getenv ("CU_REMOTE_FS");
118    }
119
120  if (done == 1 && !getenv ("CU_TEST_DUPE_INVALID"))
121    done++;  /* skip the first entry.  */
122
123  while (done++ <= 10)
124    {
125      if (!mntents[done-2].mnt_type)
126        mntents[done-2].mnt_type = "-";
127      if (!mntents[done-2].mnt_opts)
128        mntents[done-2].mnt_opts = "-";
129      if (STREQ (mntents[done-2].mnt_dir, "/NONROOT"))
130        mntents[done-2].mnt_dir = nonroot_fs;
131      if (STREQ (mntents[done-2].mnt_dir, "/REMOTE"))
132        {
133          if (!remote_fs || !*remote_fs)
134            continue;
135          else
136            mntents[done-2].mnt_dir = remote_fs;
137        }
138      return &mntents[done-2];
139    }
140
141  return NULL;
142}
143EOF
144
145# Then compile/link it:
146gcc_shared_ k.c k.so \
147  || framework_failure_ 'failed to build shared library'
148
149# Test if LD_PRELOAD works:
150LD_PRELOAD=$LD_PRELOAD:./k.so df
151test -f x || skip_ "internal test failure: maybe LD_PRELOAD doesn't work?"
152
153# The fake mtab file should only contain entries
154# having the same device number; thus the output should
155# consist of a header and unique entries.
156LD_PRELOAD=$LD_PRELOAD:./k.so df -T >out || fail=1
157test $(wc -l <out) -eq $(expr 1 + $unique_entries) || { fail=1; cat out; }
158
159# With --total we should suppress the duplicate but separate remote file system
160LD_PRELOAD=$LD_PRELOAD:./k.so df --total >out || fail=1
161test "$CU_REMOTE_FS" && elide_remote=1 || elide_remote=0
162test $(wc -l <out) -eq $(expr 2 + $unique_entries - $elide_remote) ||
163  { fail=1; cat out; }
164
165# Ensure we don't fail when unable to stat (currently) unavailable entries
166LD_PRELOAD=$LD_PRELOAD:./k.so CU_TEST_DUPE_INVALID=1 df -T >out || fail=1
167test $(wc -l <out) -eq $(expr 1 + $unique_entries) || { fail=1; cat out; }
168
169# df should also prefer "/fsname" over "fsname"
170if test "$unique_entries" = 2; then
171  test $(grep -c '/fsname' <out) -eq 1 || { fail=1; cat out; }
172  # ... and "/fsname" with '/' as Mounted on over '/.'
173  test $(grep -cF '/.' <out) -eq 0 || { fail=1; cat out; }
174fi
175
176# df should use the last seen devname (mnt_fsname) and devtype (mnt_type)
177test $(grep -c 'virtfs2.*t2' <out) -eq 1 || { fail=1; cat out; }
178
179# Ensure that filtering duplicates does not affect -a processing.
180LD_PRELOAD=$LD_PRELOAD:./k.so df -a >out || fail=1
181total_fs=6; test "$CU_REMOTE_FS" && total_fs=$(expr $total_fs + 3)
182test $(wc -l <out) -eq $total_fs || { fail=1; cat out; }
183# Ensure placeholder "-" values used for the eclipsed "virtfs"
184test $(grep -c 'virtfs *-' <out) -eq 1 || { fail=1; cat out; }
185
186# Ensure that filtering duplicates does not affect
187# argument processing (now without the fake getmntent()).
188df '.' '.' >out || fail=1
189test $(wc -l <out) -eq 3 || { fail=1; cat out; }
190
191Exit $fail
192