1 #!/bin/sh
2 # SPDX-License-Identifier: GPL-2.0
3 # description: Test tracefs GID mount option
4 # requires: "[gid=<gid>]":README
5
6 fail() {
7 local msg="$1"
8
9 echo "FAILED: $msg"
10 exit_fail
11 }
12
13 find_alternate_gid() {
14 local original_gid="$1"
15 tac /etc/group | grep -v ":$original_gid:" | head -1 | cut -d: -f3
16 }
17
18 mount_tracefs_with_options() {
19 local mount_point="$1"
20 local options="$2"
21
22 mount -t tracefs -o "$options" nodev "$mount_point"
23
24 setup
25 }
26
27 unmount_tracefs() {
28 local mount_point="$1"
29
30 # Need to make sure the mount isn't busy so that we can umount it
31 (cd $mount_point; finish_ftrace;)
32
33 cleanup
34 }
35
36 create_instance() {
37 local mount_point="$1"
38 local instance="$mount_point/instances/$(mktemp -u test-XXXXXX)"
39
40 mkdir "$instance"
41 echo "$instance"
42 }
43
44 remove_instance() {
45 local instance="$1"
46
47 rmdir "$instance"
48 }
49
50 check_gid() {
51 local mount_point="$1"
52 local expected_gid="$2"
53
54 echo "Checking permission group ..."
55
56 cd "$mount_point"
57
58 for file in "." "events" "events/sched" "events/sched/sched_switch" "events/sched/sched_switch/enable"; do
59 local gid=`stat -c "%g" $file`
60 if [ "$gid" -ne "$expected_gid" ]; then
61 cd - # Return to the previous working directory (tracefs root)
62 fail "$(realpath $file): Expected group $expected_gid; Got group $gid"
63 fi
64 done
65
66 cd - # Return to the previous working directory (tracefs root)
67 }
68
69 test_gid_mount_option() {
70 local mount_point=$(get_mount_point)
71 local mount_options=$(get_mnt_options "$mount_point")
72 local original_group=$(stat -c "%g" .)
73 local other_group=$(find_alternate_gid "$original_group")
74
75 # Set up mount options with new GID for testing
76 local new_options=`echo "$mount_options" | sed -e "s/gid=[0-9]*/gid=$other_group/"`
77 if [ "$new_options" = "$mount_options" ]; then
78 new_options="$mount_options,gid=$other_group"
79 mount_options="$mount_options,gid=$original_group"
80 fi
81
82 # Unmount existing tracefs instance and mount with new GID
83 unmount_tracefs "$mount_point"
84 mount_tracefs_with_options "$mount_point" "$new_options"
85
86 check_gid "$mount_point" "$other_group"
87
88 # Check that files created after the mount inherit the GID
89 local instance=$(create_instance "$mount_point")
90 check_gid "$instance" "$other_group"
91 remove_instance "$instance"
92
93 # Unmount and remount with the original GID
94 unmount_tracefs "$mount_point"
95 mount_tracefs_with_options "$mount_point" "$mount_options"
96 check_gid "$mount_point" "$original_group"
97 }
98
99 test_gid_mount_option
100
101 exit 0
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