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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2015 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <sys/mount.h> | |
23 | ||
24 | #include "util.h" | |
25 | #include "strv.h" | |
26 | #include "mkdir.h" | |
27 | #include "fileio.h" | |
28 | #include "cgroup-util.h" | |
29 | ||
34829a32 LP |
30 | #include "nspawn-cgroup.h" |
31 | ||
32 | int chown_cgroup(pid_t pid, uid_t uid_shift) { | |
33 | _cleanup_free_ char *path = NULL, *fs = NULL; | |
34 | _cleanup_close_ int fd = -1; | |
35 | const char *fn; | |
36 | int r; | |
37 | ||
38 | r = cg_pid_get_path(NULL, pid, &path); | |
39 | if (r < 0) | |
40 | return log_error_errno(r, "Failed to get container cgroup path: %m"); | |
41 | ||
42 | r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, path, NULL, &fs); | |
43 | if (r < 0) | |
44 | return log_error_errno(r, "Failed to get file system path for container cgroup: %m"); | |
45 | ||
46 | fd = open(fs, O_RDONLY|O_CLOEXEC|O_DIRECTORY); | |
47 | if (fd < 0) | |
48 | return log_error_errno(errno, "Failed to open %s: %m", fs); | |
49 | ||
50 | FOREACH_STRING(fn, | |
51 | ".", | |
52 | "tasks", | |
53 | "notify_on_release", | |
54 | "cgroup.procs", | |
55 | "cgroup.clone_children", | |
56 | "cgroup.controllers", | |
57 | "cgroup.subtree_control", | |
58 | "cgroup.populated") | |
59 | if (fchownat(fd, fn, uid_shift, uid_shift, 0) < 0) | |
60 | log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_WARNING, errno, | |
61 | "Failed to chown() cgroup file %s, ignoring: %m", fn); | |
62 | ||
63 | return 0; | |
64 | } | |
65 | ||
66 | int sync_cgroup(pid_t pid, bool unified_requested) { | |
67 | _cleanup_free_ char *cgroup = NULL; | |
68 | char tree[] = "/tmp/unifiedXXXXXX", pid_string[DECIMAL_STR_MAX(pid) + 1]; | |
69 | bool undo_mount = false; | |
70 | const char *fn; | |
71 | int unified, r; | |
72 | ||
73 | unified = cg_unified(); | |
74 | if (unified < 0) | |
75 | return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m"); | |
76 | ||
77 | if ((unified > 0) == unified_requested) | |
78 | return 0; | |
79 | ||
80 | /* When the host uses the legacy cgroup setup, but the | |
81 | * container shall use the unified hierarchy, let's make sure | |
82 | * we copy the path from the name=systemd hierarchy into the | |
83 | * unified hierarchy. Similar for the reverse situation. */ | |
84 | ||
85 | r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cgroup); | |
86 | if (r < 0) | |
87 | return log_error_errno(r, "Failed to get control group of " PID_FMT ": %m", pid); | |
88 | ||
89 | /* In order to access the unified hierarchy we need to mount it */ | |
90 | if (!mkdtemp(tree)) | |
91 | return log_error_errno(errno, "Failed to generate temporary mount point for unified hierarchy: %m"); | |
92 | ||
93 | if (unified) | |
94 | r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "none,name=systemd,xattr"); | |
95 | else | |
96 | r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "__DEVEL__sane_behavior"); | |
97 | if (r < 0) { | |
98 | r = log_error_errno(errno, "Failed to mount unified hierarchy: %m"); | |
99 | goto finish; | |
100 | } | |
101 | ||
102 | undo_mount = true; | |
103 | ||
104 | fn = strjoina(tree, cgroup, "/cgroup.procs"); | |
105 | (void) mkdir_parents(fn, 0755); | |
106 | ||
107 | sprintf(pid_string, PID_FMT, pid); | |
108 | r = write_string_file(fn, pid_string, 0); | |
109 | if (r < 0) | |
110 | log_error_errno(r, "Failed to move process: %m"); | |
111 | ||
112 | finish: | |
113 | if (undo_mount) | |
114 | (void) umount(tree); | |
115 | ||
116 | (void) rmdir(tree); | |
117 | return r; | |
118 | } | |
119 | ||
120 | int create_subcgroup(pid_t pid, bool unified_requested) { | |
121 | _cleanup_free_ char *cgroup = NULL; | |
122 | const char *child; | |
123 | int unified, r; | |
124 | CGroupMask supported; | |
125 | ||
126 | /* In the unified hierarchy inner nodes may only only contain | |
127 | * subgroups, but not processes. Hence, if we running in the | |
128 | * unified hierarchy and the container does the same, and we | |
129 | * did not create a scope unit for the container move us and | |
130 | * the container into two separate subcgroups. */ | |
131 | ||
132 | if (!unified_requested) | |
133 | return 0; | |
134 | ||
135 | unified = cg_unified(); | |
136 | if (unified < 0) | |
137 | return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m"); | |
138 | if (unified == 0) | |
139 | return 0; | |
140 | ||
141 | r = cg_mask_supported(&supported); | |
142 | if (r < 0) | |
143 | return log_error_errno(r, "Failed to determine supported controllers: %m"); | |
144 | ||
145 | r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &cgroup); | |
146 | if (r < 0) | |
147 | return log_error_errno(r, "Failed to get our control group: %m"); | |
148 | ||
149 | child = strjoina(cgroup, "/payload"); | |
150 | r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, pid); | |
151 | if (r < 0) | |
152 | return log_error_errno(r, "Failed to create %s subcgroup: %m", child); | |
153 | ||
154 | child = strjoina(cgroup, "/supervisor"); | |
155 | r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, 0); | |
156 | if (r < 0) | |
157 | return log_error_errno(r, "Failed to create %s subcgroup: %m", child); | |
158 | ||
159 | /* Try to enable as many controllers as possible for the new payload. */ | |
160 | (void) cg_enable_everywhere(supported, supported, cgroup); | |
161 | return 0; | |
162 | } |