]>
git.proxmox.com Git - mirror_lxcfs.git/blob - pam/pam_cgfs.c
3 * Copyright © 2016 Canonical, Inc
4 * Author: Serge Hallyn <serge.hallyn@ubuntu.com>
5 * Author: Christian Brauner <christian.brauner@ubuntu.com>
7 * When a user logs in, this pam module will create cgroups which the user may
8 * administer. It handles both pure cgroupfs v1 and pure cgroupfs v2, as well as
9 * mixed mounts, where some controllers are mounted in a standard cgroupfs v1
10 * hierarchy location (/sys/fs/cgroup/<controller>) and others are in the
11 * cgroupfs v2 hierarchy.
12 * Writeable cgroups are either created for all controllers or, if specified,
13 * for any controllers listed on the command line.
14 * The cgroup created will be "user/$user/0" for the first session,
15 * "user/$user/1" for the second, etc.
17 * Systems with a systemd init system are treated specially, both with respect
18 * to cgroupfs v1 and cgroupfs v2. For both, cgroupfs v1 and cgroupfs v2, We
19 * check whether systemd already placed us in a cgroup it created:
21 * user.slice/user-uid.slice/session-n.scope
23 * by checking whether uid == our uid. If it did, we simply chown the last
24 * part (session-n.scope). If it did not we create a cgroup as outlined above
25 * (user/$user/n) and chown it to our uid.
26 * The same holds for cgroupfs v2 where this assumptions becomes crucial:
27 * We __have to__ be placed in our under the cgroup systemd created for us on
28 * login, otherwise things like starting an xserver or similar will not work.
30 * All requested cgroups must be mounted under /sys/fs/cgroup/$controller,
31 * no messing around with finding mountpoints.
33 * See COPYING file for details.
49 #include <linux/unistd.h>
50 #include <sys/mount.h>
51 #include <sys/param.h>
53 #include <sys/types.h>
56 #define PAM_SM_SESSION
57 #include <security/_pam_macros.h>
58 #include <security/pam_modules.h>
62 #ifndef CGROUP_SUPER_MAGIC
63 #define CGROUP_SUPER_MAGIC 0x27e0eb
66 #ifndef CGROUP2_SUPER_MAGIC
67 #define CGROUP2_SUPER_MAGIC 0x63677270
70 /* Taken over modified from the kernel sources. */
71 #define NBITS 32 /* bits in uint32_t */
72 #define DIV_ROUND_UP(n, d) (((n) + (d)-1) / (d))
73 #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, NBITS)
75 static enum cg_mount_mode
{
80 CGROUP_UNINITIALIZED
= 3,
81 } cg_mount_mode
= CGROUP_UNINITIALIZED
;
83 /* Common helper functions. Most of these have been taken from LXC. */
84 static void append_line(char **dest
, size_t oldlen
, char *new, size_t newlen
);
85 static int append_null_to_list(void ***list
);
86 static void batch_realloc(char **mem
, size_t oldlen
, size_t newlen
);
87 static inline void clear_bit(unsigned bit
, uint32_t *bitarr
)
89 bitarr
[bit
/ NBITS
] &= ~(1 << (bit
% NBITS
));
91 static char *copy_to_eol(char *s
);
92 static bool file_exists(const char *f
);
93 static void free_string_list(char **list
);
94 static char *get_mountpoint(char *line
);
95 static bool get_uid_gid(const char *user
, uid_t
*uid
, gid_t
*gid
);
96 static int handle_login(const char *user
, uid_t uid
, gid_t gid
);
97 static inline bool is_set(unsigned bit
, uint32_t *bitarr
)
99 return (bitarr
[bit
/ NBITS
] & (1 << (bit
% NBITS
))) != 0;
101 /* __typeof__ should be safe to use with all compilers. */
102 typedef __typeof__(((struct statfs
*)NULL
)->f_type
) fs_type_magic
;
103 static bool has_fs_type(const struct statfs
*fs
, fs_type_magic magic_val
);
104 static bool is_lxcfs(const char *line
);
105 static bool is_cgv1(char *line
);
106 static bool is_cgv2(char *line
);
107 static bool mkdir_p(const char *root
, char *path
);
108 static void *must_alloc(size_t sz
);
109 static void must_add_to_list(char ***clist
, char *entry
);
110 static void must_append_controller(char **klist
, char **nlist
, char ***clist
,
112 static void must_append_string(char ***list
, char *entry
);
113 static char *must_copy_string(const char *entry
);
114 static char *must_make_path(const char *first
, ...) __attribute__((sentinel
));
115 static void *must_realloc(void *orig
, size_t sz
);
116 static void mysyslog(int err
, const char *format
, ...) __attribute__((sentinel
));
117 static char *read_file(char *fnam
);
118 static int read_from_file(const char *filename
, void* buf
, size_t count
);
119 static int recursive_rmdir(char *dirname
);
120 static inline void set_bit(unsigned bit
, uint32_t *bitarr
)
122 bitarr
[bit
/ NBITS
] |= (1 << (bit
% NBITS
));
124 static bool string_in_list(char **list
, const char *entry
);
125 static char *string_join(const char *sep
, const char **parts
, bool use_as_prefix
);
126 static void trim(char *s
);
127 static bool write_int(char *path
, int v
);
128 static ssize_t
write_nointr(int fd
, const void* buf
, size_t count
);
129 static int write_to_file(const char *filename
, const void *buf
, size_t count
,
132 /* cgroupfs prototypes. */
133 static bool cg_belongs_to_uid_gid(const char *path
, uid_t uid
, gid_t gid
);
134 static uint32_t *cg_cpumask(char *buf
, size_t nbits
);
135 static bool cg_copy_parent_file(char *path
, char *file
);
136 static char *cg_cpumask_to_cpulist(uint32_t *bitarr
, size_t nbits
);
137 static bool cg_enter(const char *cgroup
);
138 static void cg_escape(void);
139 static bool cg_filter_and_set_cpus(char *path
, bool am_initialized
);
140 static ssize_t
cg_get_max_cpus(char *cpulist
);
141 static int cg_get_version_of_mntpt(const char *path
);
142 static bool cg_init(uid_t uid
, gid_t gid
);
143 static void cg_mark_to_make_rw(const char *cstring
);
144 static void cg_prune_empty_cgroups(const char *user
);
145 static bool cg_systemd_created_user_slice(const char *base_cgroup
,
146 const char *init_cgroup
,
147 const char *in
, uid_t uid
);
148 static bool cg_systemd_chown_existing_cgroup(const char *mountpoint
,
149 const char *base_cgroup
, uid_t uid
,
151 bool systemd_user_slice
);
152 static bool cg_systemd_under_user_slice_1(const char *in
, uid_t uid
);
153 static bool cg_systemd_under_user_slice_2(const char *base_cgroup
,
154 const char *init_cgroup
, uid_t uid
);
155 static void cg_systemd_prune_init_scope(char *cg
);
156 static bool is_lxcfs(const char *line
);
158 /* cgroupfs v1 prototypes. */
159 struct cgv1_hierarchy
{
165 bool create_rw_cgroup
;
166 bool systemd_user_slice
;
169 static struct cgv1_hierarchy
**cgv1_hierarchies
;
171 static void cgv1_add_controller(char **clist
, char *mountpoint
,
172 char *base_cgroup
, char *init_cgroup
);
173 static bool cgv1_controller_in_clist(char *cgline
, char *c
);
174 static bool cgv1_controller_lists_intersect(char **l1
, char **l2
);
175 static bool cgv1_controller_list_is_dup(struct cgv1_hierarchy
**hlist
,
177 static bool cgv1_create(const char *cgroup
, uid_t uid
, gid_t gid
,
179 static bool cgv1_create_one(struct cgv1_hierarchy
*h
, const char *cgroup
,
180 uid_t uid
, gid_t gid
, bool *existed
);
181 static bool cgv1_enter(const char *cgroup
);
182 static void cgv1_escape(void);
183 static bool cgv1_get_controllers(char ***klist
, char ***nlist
);
184 static char *cgv1_get_current_cgroup(char *basecginfo
, char *controller
);
185 static char **cgv1_get_proc_mountinfo_controllers(char **klist
, char **nlist
,
187 static bool cgv1_handle_cpuset_hierarchy(struct cgv1_hierarchy
*h
,
189 static bool cgv1_handle_root_cpuset_hierarchy(struct cgv1_hierarchy
*h
);
190 static bool cgv1_init(uid_t uid
, gid_t gid
);
191 static void cgv1_mark_to_make_rw(char **clist
);
192 static char *cgv1_must_prefix_named(char *entry
);
193 static bool cgv1_prune_empty_cgroups(const char *user
);
194 static bool cgv1_remove_one(struct cgv1_hierarchy
*h
, const char *cgroup
);
195 static bool is_cgv1(char *line
);
197 /* cgroupfs v2 prototypes. */
198 struct cgv2_hierarchy
{
204 bool create_rw_cgroup
;
205 bool systemd_user_slice
;
208 /* Actually this should only be a single hierarchy. But for the sake of
209 * parallelism and because the layout of the cgroupfs v2 is still somewhat
210 * changing, we'll leave it as an array of structs.
212 static struct cgv2_hierarchy
**cgv2_hierarchies
;
214 static void cgv2_add_controller(char **clist
, char *mountpoint
,
215 char *base_cgroup
, char *init_cgroup
,
216 bool systemd_user_slice
);
217 static bool cgv2_create(const char *cgroup
, uid_t uid
, gid_t gid
,
219 static bool cgv2_enter(const char *cgroup
);
220 static void cgv2_escape(void);
221 static char *cgv2_get_current_cgroup(int pid
);
222 static bool cgv2_init(uid_t uid
, gid_t gid
);
223 static void cgv2_mark_to_make_rw(char **clist
);
224 static bool cgv2_prune_empty_cgroups(const char *user
);
225 static bool cgv2_remove(const char *cgroup
);
226 static bool is_cgv2(char *line
);
228 /* Common helper functions. Most of these have been taken from LXC. */
229 static void mysyslog(int err
, const char *format
, ...)
233 va_start(args
, format
);
234 openlog("PAM-CGFS", LOG_CONS
| LOG_PID
, LOG_AUTH
);
235 vsyslog(err
, format
, args
);
240 /* realloc() pointer; do not fail. */
241 static void *must_realloc(void *orig
, size_t sz
)
246 ret
= realloc(orig
, sz
);
252 /* realloc() pointer in batch sizes; do not fail. */
253 #define BATCH_SIZE 50
254 static void batch_realloc(char **mem
, size_t oldlen
, size_t newlen
)
256 int newbatches
= (newlen
/ BATCH_SIZE
) + 1;
257 int oldbatches
= (oldlen
/ BATCH_SIZE
) + 1;
259 if (!*mem
|| newbatches
> oldbatches
)
260 *mem
= must_realloc(*mem
, newbatches
* BATCH_SIZE
);
263 /* Append lines as is to pointer; do not fail. */
264 static void append_line(char **dest
, size_t oldlen
, char *new, size_t newlen
)
266 size_t full
= oldlen
+ newlen
;
268 batch_realloc(dest
, oldlen
, full
+ 1);
270 memcpy(*dest
+ oldlen
, new, newlen
+ 1);
273 /* Read in whole file and return allocated pointer. */
274 static char *read_file(char *fnam
)
278 char *line
= NULL
, *buf
= NULL
;
279 size_t len
= 0, fulllen
= 0;
281 f
= fopen(fnam
, "r");
285 while ((linelen
= getline(&line
, &len
, f
)) != -1) {
286 append_line(&buf
, fulllen
, line
, linelen
);
296 /* Given a pointer to a null-terminated array of pointers, realloc to add one
297 * entry, and point the new entry to NULL. Do not fail. Return the index to the
298 * second-to-last entry - that is, the one which is now available for use
299 * (keeping the list null-terminated).
301 static int append_null_to_list(void ***list
)
306 for (; (*list
)[newentry
]; newentry
++) {
310 *list
= must_realloc(*list
, (newentry
+ 2) * sizeof(void **));
311 (*list
)[newentry
+ 1] = NULL
;
316 /* Make allocated copy of string; do not fail. */
317 static char *must_copy_string(const char *entry
)
331 /* Append new entry to null-terminated array of pointer; make sure that array of
332 * pointers will still be null-terminated.
334 static void must_append_string(char ***list
, char *entry
)
339 newentry
= append_null_to_list((void ***)list
);
340 copy
= must_copy_string(entry
);
341 (*list
)[newentry
] = copy
;
344 /* Remove newlines from string. */
345 static void trim(char *s
)
347 size_t len
= strlen(s
);
349 while ((len
> 0) && s
[len
- 1] == '\n')
353 /* Allocate pointer; do not fail. */
354 static void *must_alloc(size_t sz
)
356 return must_realloc(NULL
, sz
);
359 /* Make allocated copy of string. End of string is taken to be '\n'. */
360 static char *copy_to_eol(char *s
)
362 char *newline
, *sret
;
365 newline
= strchr(s
, '\n');
370 sret
= must_alloc(len
+ 1);
371 memcpy(sret
, s
, len
);
377 /* Check if given entry under /proc/<pid>/mountinfo is a fuse.lxcfs mount. */
378 static bool is_lxcfs(const char *line
)
380 char *p
= strstr(line
, " - ");
384 return strncmp(p
, " - fuse.lxcfs ", 14) == 0;
387 /* Check if given entry under /proc/<pid>/mountinfo is a cgroupfs v1 mount. */
388 static bool is_cgv1(char *line
)
390 char *p
= strstr(line
, " - ");
394 return strncmp(p
, " - cgroup ", 10) == 0;
397 /* Check if given entry under /proc/<pid>/mountinfo is a cgroupfs v2 mount. */
398 static bool is_cgv2(char *line
)
400 char *p
= strstr(line
, " - ");
404 return strncmp(p
, " - cgroup2 ", 11) == 0;
407 /* Given a null-terminated array of strings, check whether @entry is one of the
410 static bool string_in_list(char **list
, const char *entry
)
414 for (it
= list
; it
&& *it
; it
++)
415 if (strcmp(*it
, entry
) == 0)
421 /* Free null-terminated array of strings. */
422 static void free_string_list(char **list
)
426 for (it
= list
; it
&& *it
; it
++)
431 /* Concatenate all passed-in strings into one path. Do not fail. If any piece
432 * is not prefixed with '/', add a '/'. Does not remove duplicate '///' from the
435 static char *must_make_path(const char *first
, ...)
441 full_len
= strlen(first
);
443 dest
= must_copy_string(first
);
445 va_start(args
, first
);
446 while ((cur
= va_arg(args
, char *)) != NULL
) {
447 full_len
+= strlen(cur
);
452 dest
= must_realloc(dest
, full_len
+ 1);
464 /* Write single integer to file. */
465 static bool write_int(char *path
, int v
)
470 f
= fopen(path
, "w");
474 if (fprintf(f
, "%d\n", v
) < 0)
483 /* Check if a given file exists. */
484 static bool file_exists(const char *f
)
488 return stat(f
, &statbuf
) == 0;
491 /* Create directory and (if necessary) its parents. */
492 static bool mkdir_p(const char *root
, char *path
)
496 if (strlen(path
) < strlen(root
))
499 if (strlen(path
) == strlen(root
))
502 b
= path
+ strlen(root
) + 1;
504 while (*b
&& (*b
== '/'))
510 while (*e
&& *e
!= '/')
517 if (file_exists(path
))
520 if (mkdir(path
, 0755) < 0) {
521 lxcfs_debug("Failed to create %s: %s.\n", path
, strerror(errno
));
536 /* Recursively remove directory and its parents. */
537 static int recursive_rmdir(char *dirname
)
539 struct dirent
*direntp
;
543 dir
= opendir(dirname
);
547 while ((direntp
= readdir(dir
))) {
554 if (!strcmp(direntp
->d_name
, ".") ||
555 !strcmp(direntp
->d_name
, ".."))
558 pathname
= must_make_path(dirname
, direntp
->d_name
, NULL
);
560 if (lstat(pathname
, &st
)) {
562 lxcfs_debug("Failed to stat %s.\n", pathname
);
567 if (!S_ISDIR(st
.st_mode
))
570 if (recursive_rmdir(pathname
) < 0)
576 if (rmdir(dirname
) < 0) {
578 lxcfs_debug("Failed to delete %s: %s.\n", dirname
, strerror(errno
));
582 if (closedir(dir
) < 0) {
584 lxcfs_debug("Failed to delete %s: %s.\n", dirname
, strerror(errno
));
591 /* Add new entry to null-terminated array of pointers. Make sure array is still
594 static void must_add_to_list(char ***clist
, char *entry
)
598 newentry
= append_null_to_list((void ***)clist
);
599 (*clist
)[newentry
] = must_copy_string(entry
);
602 /* Get mountpoint from a /proc/<pid>/mountinfo line. */
603 static char *get_mountpoint(char *line
)
611 for (i
= 0; i
< 4; i
++) {
623 sret
= must_alloc(len
+ 1);
624 memcpy(sret
, p
, len
);
630 /* Create list of cgroupfs v1 controller found under /proc/self/cgroup. Skips
631 * the 0::/some/path cgroupfs v2 hierarchy listed. Splits controllers into
632 * kernel controllers (@klist) and named controllers (@nlist).
634 static bool cgv1_get_controllers(char ***klist
, char ***nlist
)
640 f
= fopen("/proc/self/cgroup", "r");
644 while (getline(&line
, &len
, f
) != -1) {
646 char *saveptr
= NULL
;
648 p
= strchr(line
, ':');
658 /* Skip the v2 hierarchy. */
662 for (tok
= strtok_r(p
, ",", &saveptr
); tok
;
663 tok
= strtok_r(NULL
, ",", &saveptr
)) {
664 if (strncmp(tok
, "name=", 5) == 0)
665 must_append_string(nlist
, tok
);
667 must_append_string(klist
, tok
);
677 /* Get list of controllers for cgroupfs v2 hierarchy by looking at
678 * cgroup.controllers and/or cgroup.subtree_control of a given (parent) cgroup.
679 static bool cgv2_get_controllers(char ***klist)
685 /* Get current cgroup from /proc/self/cgroup for the cgroupfs v2 hierarchy. */
686 static char *cgv2_get_current_cgroup(int pid
)
690 char *current_cgroup
;
692 /* The largest integer that can fit into long int is 2^64. This is a
693 * 20-digit number. */
694 #define __PIDLEN /* /proc */ 5 + /* /pid-to-str */ 21 + /* /cgroup */ 7 + /* \0 */ 1
697 ret
= snprintf(path
, __PIDLEN
, "/proc/%d/cgroup", pid
);
698 if (ret
< 0 || ret
>= __PIDLEN
)
701 cgroups_v2
= read_file(path
);
705 current_cgroup
= strstr(cgroups_v2
, "0::/");
709 current_cgroup
= current_cgroup
+ 3;
710 copy
= copy_to_eol(current_cgroup
);
722 /* Given two null-terminated lists of strings, return true if any string is in
725 static bool cgv1_controller_lists_intersect(char **l1
, char **l2
)
732 for (it
= l1
; it
&& *it
; it
++)
733 if (string_in_list(l2
, *it
))
739 /* For a null-terminated list of controllers @clist, return true if any of those
740 * controllers is already listed the null-terminated list of hierarchies @hlist.
741 * Realistically, if one is present, all must be present.
743 static bool cgv1_controller_list_is_dup(struct cgv1_hierarchy
**hlist
, char **clist
)
745 struct cgv1_hierarchy
**it
;
747 for (it
= hlist
; it
&& *it
; it
++)
748 if ((*it
)->controllers
)
749 if (cgv1_controller_lists_intersect((*it
)->controllers
, clist
))
755 /* Set boolean to mark controllers under which we are supposed create a
758 static void cgv1_mark_to_make_rw(char **clist
)
760 struct cgv1_hierarchy
**it
;
762 for (it
= cgv1_hierarchies
; it
&& *it
; it
++)
763 if ((*it
)->controllers
)
764 if (cgv1_controller_lists_intersect((*it
)->controllers
, clist
))
765 (*it
)->create_rw_cgroup
= true;
768 /* Set boolean to mark whether we are supposed to create a writeable cgroup in
769 * the cgroupfs v2 hierarchy.
771 static void cgv2_mark_to_make_rw(char **clist
)
773 if (string_in_list(clist
, "unified"))
774 if (cgv2_hierarchies
)
775 (*cgv2_hierarchies
)->create_rw_cgroup
= true;
778 /* Wrapper around cgv{1,2}_mark_to_make_rw(). */
779 static void cg_mark_to_make_rw(const char *cstring
)
782 char *saveptr
= NULL
;
785 copy
= must_copy_string(cstring
);
787 for (tok
= strtok_r(copy
, ",", &saveptr
); tok
;
788 tok
= strtok_r(NULL
, ",", &saveptr
))
789 must_add_to_list(&clist
, tok
);
793 cgv1_mark_to_make_rw(clist
);
794 cgv2_mark_to_make_rw(clist
);
796 free_string_list(clist
);
799 /* Prefix any named controllers with "name=", e.g. "name=systemd". */
800 static char *cgv1_must_prefix_named(char *entry
)
807 s
= must_alloc(len
+ 6);
809 ret
= snprintf(s
, len
+ 6, "name=%s", entry
);
810 if (ret
< 0 || (size_t)ret
>= (len
+ 6))
816 /* Append kernel controller in @klist or named controller in @nlist to @clist */
817 static void must_append_controller(char **klist
, char **nlist
, char ***clist
, char *entry
)
822 if (string_in_list(klist
, entry
) && string_in_list(nlist
, entry
))
825 newentry
= append_null_to_list((void ***)clist
);
827 if (strncmp(entry
, "name=", 5) == 0)
828 copy
= must_copy_string(entry
);
829 else if (string_in_list(klist
, entry
))
830 copy
= must_copy_string(entry
);
832 copy
= cgv1_must_prefix_named(entry
);
834 (*clist
)[newentry
] = copy
;
837 /* Get the controllers from a mountinfo line. There are other ways we could get
838 * this info. For lxcfs, field 3 is /cgroup/controller-list. For cgroupfs, we
839 * could parse the mount options. But we simply assume that the mountpoint must
840 * be /sys/fs/cgroup/controller-list
842 static char **cgv1_get_proc_mountinfo_controllers(char **klist
, char **nlist
, char *line
)
846 char *saveptr
= NULL
;
851 for (i
= 0; i
< 4; i
++) {
860 if (strncmp(p
, "/sys/fs/cgroup/", 15) != 0)
870 for (tok
= strtok_r(p
, ",", &saveptr
); tok
;
871 tok
= strtok_r(NULL
, ",", &saveptr
))
872 must_append_controller(klist
, nlist
, &aret
, tok
);
877 /* Check if a cgroupfs v2 controller is present in the string @cgline. */
878 static bool cgv1_controller_in_clist(char *cgline
, char *c
)
881 char *tok
, *eol
, *tmp
;
882 char *saveptr
= NULL
;
884 eol
= strchr(cgline
, ':');
889 tmp
= alloca(len
+ 1);
890 memcpy(tmp
, cgline
, len
);
893 for (tok
= strtok_r(tmp
, ",", &saveptr
); tok
;
894 tok
= strtok_r(NULL
, ",", &saveptr
)) {
895 if (strcmp(tok
, c
) == 0)
901 /* Get current cgroup from the /proc/<pid>/cgroup file passed in via @basecginfo
902 * of a given cgv1 controller passed in via @controller.
904 static char *cgv1_get_current_cgroup(char *basecginfo
, char *controller
)
916 if (cgv1_controller_in_clist(p
, controller
)) {
922 return copy_to_eol(p
);
934 /* Remove /init.scope from string @cg. This will mostly affect systemd-based
937 #define INIT_SCOPE "/init.scope"
938 static void cg_systemd_prune_init_scope(char *cg
)
945 point
= cg
+ strlen(cg
) - strlen(INIT_SCOPE
);
949 if (strcmp(point
, INIT_SCOPE
) == 0) {
957 /* Add new info about a mounted cgroupfs v1 hierarchy. Includes the controllers
958 * mounted into that hierarchy (e.g. cpu,cpuacct), the mountpoint of that
959 * hierarchy (/sys/fs/cgroup/<controller>, the base cgroup of the current
960 * process gathered from /proc/self/cgroup, and the init cgroup of PID1 gathered
961 * from /proc/1/cgroup.
963 static void cgv1_add_controller(char **clist
, char *mountpoint
, char *base_cgroup
, char *init_cgroup
)
965 struct cgv1_hierarchy
*new;
968 new = must_alloc(sizeof(*new));
969 new->controllers
= clist
;
970 new->mountpoint
= mountpoint
;
971 new->base_cgroup
= base_cgroup
;
972 new->fullcgpath
= NULL
;
973 new->create_rw_cgroup
= false;
974 new->init_cgroup
= init_cgroup
;
975 new->systemd_user_slice
= false;
977 newentry
= append_null_to_list((void ***)&cgv1_hierarchies
);
978 cgv1_hierarchies
[newentry
] = new;
981 /* Add new info about the mounted cgroupfs v2 hierarchy. Can (but doesn't
982 * currently) include the controllers mounted into the hierarchy (e.g. memory,
983 * pids, blkio), the mountpoint of that hierarchy (Should usually be
984 * /sys/fs/cgroup but some init systems seems to think it might be a good idea
985 * to also mount empty cgroupfs v2 hierarchies at /sys/fs/cgroup/systemd.), the
986 * base cgroup of the current process gathered from /proc/self/cgroup, and the
987 * init cgroup of PID1 gathered from /proc/1/cgroup.
989 static void cgv2_add_controller(char **clist
, char *mountpoint
, char *base_cgroup
, char *init_cgroup
, bool systemd_user_slice
)
991 struct cgv2_hierarchy
*new;
994 new = must_alloc(sizeof(*new));
995 new->controllers
= clist
;
996 new->mountpoint
= mountpoint
;
997 new->base_cgroup
= base_cgroup
;
998 new->fullcgpath
= NULL
;
999 new->create_rw_cgroup
= false;
1000 new->init_cgroup
= init_cgroup
;
1001 new->systemd_user_slice
= systemd_user_slice
;
1003 newentry
= append_null_to_list((void ***)&cgv2_hierarchies
);
1004 cgv2_hierarchies
[newentry
] = new;
1007 /* In Ubuntu 14.04, the paths created for us were
1008 * '/user/$uid.user/$something.session' This can be merged better with
1009 * systemd_created_slice_for_us(), but keeping it separate makes it easier to
1010 * reason about the correctness.
1012 static bool cg_systemd_under_user_slice_1(const char *in
, uid_t uid
)
1020 copy
= must_copy_string(in
);
1021 if (strlen(copy
) < strlen("/user/1.user/1.session"))
1023 p
= copy
+ strlen(copy
) - 1;
1025 /* skip any trailing '/' (shouldn't be any, but be sure) */
1026 while (p
>= copy
&& *p
== '/')
1031 /* Get last path element */
1032 while (p
>= copy
&& *p
!= '/')
1036 /* make sure it is something.session */
1037 len
= strlen(p
+ 1);
1038 if (len
< strlen("1.session") ||
1039 strncmp(p
+ 1 + len
- 8, ".session", 8) != 0)
1042 /* ok last path piece checks out, now check the second to last */
1044 while (p
>= copy
&& *(--p
) != '/')
1046 if (sscanf(p
+ 1, "%d.user/", &id
) != 1)
1059 /* So long as our path relative to init starts with /user.slice/user-$uid.slice,
1060 * assume it belongs to $uid and chown it
1062 static bool cg_systemd_under_user_slice_2(const char *base_cgroup
,
1063 const char *init_cgroup
, uid_t uid
)
1067 size_t curlen
, initlen
;
1069 curlen
= strlen(base_cgroup
);
1070 initlen
= strlen(init_cgroup
);
1071 if (curlen
<= initlen
)
1074 if (strncmp(base_cgroup
, init_cgroup
, initlen
) != 0)
1077 ret
= snprintf(buf
, 100, "/user.slice/user-%d.slice/", (int)uid
);
1078 if (ret
< 0 || ret
>= 100)
1082 initlen
= 0; // skip the '/'
1084 return strncmp(base_cgroup
+ initlen
, buf
, strlen(buf
)) == 0;
1087 /* The systemd-created path is: user-$uid.slice/session-c$session.scope. If that
1088 * is not the end of our systemd path, then we're not part of the PAM call that
1089 * created that path.
1091 * The last piece is chowned to $uid, the user- part not.
1092 * Note: If the user creates paths that look like what we're looking for to
1094 * - they fool us, we create new cgroups, and they get auto-logged-out.
1095 * - they fool a root sudo, systemd cgroup is not changed but chowned, and they
1096 * lose ownership of their cgroups
1098 static bool cg_systemd_created_user_slice(const char *base_cgroup
,
1099 const char *init_cgroup
,
1100 const char *in
, uid_t uid
)
1108 copy
= must_copy_string(in
);
1110 /* An old version of systemd has already created a cgroup for us. */
1111 if (cg_systemd_under_user_slice_1(in
, uid
))
1114 /* A new version of systemd has already created a cgroup for us. */
1115 if (cg_systemd_under_user_slice_2(base_cgroup
, init_cgroup
, uid
))
1118 if (strlen(copy
) < strlen("/user-0.slice/session-0.scope"))
1121 p
= copy
+ strlen(copy
) - 1;
1122 /* Skip any trailing '/' (shouldn't be any, but be sure). */
1123 while (p
>= copy
&& *p
== '/')
1129 /* Get last path element */
1130 while (p
>= copy
&& *p
!= '/')
1136 /* Make sure it is session-something.scope. */
1137 len
= strlen(p
+ 1);
1138 if (strncmp(p
+ 1, "session-", strlen("session-")) != 0 ||
1139 strncmp(p
+ 1 + len
- 6, ".scope", 6) != 0)
1142 /* Ok last path piece checks out, now check the second to last. */
1144 while (p
>= copy
&& *(--p
) != '/')
1147 if (sscanf(p
+ 1, "user-%d.slice/", &id
) != 1)
1160 /* Chown existing cgroup that systemd has already created for us. */
1161 static bool cg_systemd_chown_existing_cgroup(const char *mountpoint
,
1162 const char *base_cgroup
, uid_t uid
,
1163 gid_t gid
, bool systemd_user_slice
)
1167 if (!systemd_user_slice
)
1170 path
= must_make_path(mountpoint
, base_cgroup
, NULL
);
1172 /* A cgroup within name=systemd has already been created. So we only
1175 if (chown(path
, uid
, gid
) < 0)
1176 mysyslog(LOG_WARNING
, "Failed to chown %s to %d:%d: %s.\n",
1177 path
, (int)uid
, (int)gid
, strerror(errno
), NULL
);
1178 lxcfs_debug("Chowned %s to %d:%d.\n", path
, (int)uid
, (int)gid
);
1184 /* Detect and store information about cgroupfs v1 hierarchies. */
1185 static bool cgv1_init(uid_t uid
, gid_t gid
)
1188 struct cgv1_hierarchy
**it
;
1191 char **klist
= NULL
, **nlist
= NULL
;
1194 basecginfo
= read_file("/proc/self/cgroup");
1198 f
= fopen("/proc/self/mountinfo", "r");
1204 cgv1_get_controllers(&klist
, &nlist
);
1206 while (getline(&line
, &len
, f
) != -1) {
1207 char **controller_list
= NULL
;
1208 char *mountpoint
, *base_cgroup
;
1210 if (is_lxcfs(line
) || !is_cgv1(line
))
1213 controller_list
= cgv1_get_proc_mountinfo_controllers(klist
, nlist
, line
);
1214 if (!controller_list
)
1217 if (cgv1_controller_list_is_dup(cgv1_hierarchies
,
1219 free(controller_list
);
1223 mountpoint
= get_mountpoint(line
);
1225 free_string_list(controller_list
);
1229 base_cgroup
= cgv1_get_current_cgroup(basecginfo
, controller_list
[0]);
1231 free_string_list(controller_list
);
1236 lxcfs_debug("Detected cgroupfs v1 controller \"%s\" with "
1237 "mountpoint \"%s\" and cgroup \"%s\".\n",
1238 controller_list
[0], mountpoint
, base_cgroup
);
1239 cgv1_add_controller(controller_list
, mountpoint
, base_cgroup
,
1242 free_string_list(klist
);
1243 free_string_list(nlist
);
1248 /* Retrieve init cgroup path for all controllers. */
1249 basecginfo
= read_file("/proc/1/cgroup");
1253 for (it
= cgv1_hierarchies
; it
&& *it
; it
++) {
1254 if ((*it
)->controllers
) {
1255 char *init_cgroup
, *user_slice
;
1256 /* We've already stored the controller and received its
1257 * current cgroup. If we now fail to retrieve its init
1258 * cgroup, we should probably fail.
1260 init_cgroup
= cgv1_get_current_cgroup(basecginfo
, (*it
)->controllers
[0]);
1265 cg_systemd_prune_init_scope(init_cgroup
);
1266 (*it
)->init_cgroup
= init_cgroup
;
1267 lxcfs_debug("cgroupfs v1 controller \"%s\" has init "
1269 (*(*it
)->controllers
), init_cgroup
);
1270 /* Check whether systemd has already created a cgroup
1273 user_slice
= must_make_path((*it
)->mountpoint
, (*it
)->base_cgroup
, NULL
);
1274 if (cg_systemd_created_user_slice((*it
)->base_cgroup
, (*it
)->init_cgroup
, user_slice
, uid
))
1275 (*it
)->systemd_user_slice
= true;
1283 /* __typeof__ should be safe to use with all compilers. */
1284 typedef __typeof__(((struct statfs
*)NULL
)->f_type
) fs_type_magic
;
1285 /* Check whether given mountpoint has mount type specified via @magic_val. */
1286 static bool has_fs_type(const struct statfs
*fs
, fs_type_magic magic_val
)
1288 return (fs
->f_type
== (fs_type_magic
)magic_val
);
1291 /* Check whether @path is a cgroupfs v1 or cgroupfs v2 mount. Returns -1 if
1292 * statfs fails. If @path is null /sys/fs/cgroup is checked.
1294 static int cg_get_version_of_mntpt(const char *path
)
1300 ret
= statfs(path
, &sb
);
1302 ret
= statfs("/sys/fs/cgroup", &sb
);
1307 if (has_fs_type(&sb
, CGROUP_SUPER_MAGIC
))
1309 else if (has_fs_type(&sb
, CGROUP2_SUPER_MAGIC
))
1315 /* Detect and store information about the cgroupfs v2 hierarchy. Currently only
1316 * deals with the empty v2 hierachy as we do not retrieve enabled controllers.
1318 static bool cgv2_init(uid_t uid
, gid_t gid
)
1322 char *current_cgroup
= NULL
, *init_cgroup
= NULL
;
1327 current_cgroup
= cgv2_get_current_cgroup(getpid());
1328 if (!current_cgroup
) {
1329 /* No v2 hierarchy present. We're done. */
1334 init_cgroup
= cgv2_get_current_cgroup(1);
1336 /* If we're here and didn't fail already above, then something's
1337 * certainly wrong, so error this time.
1341 cg_systemd_prune_init_scope(init_cgroup
);
1343 /* Check if the v2 hierarchy is mounted at its standard location.
1344 * If so we can skip the rest of the work here. Although the unified
1345 * hierarchy can be mounted multiple times, each of those mountpoints
1346 * will expose identical information.
1348 if (cg_get_version_of_mntpt("/sys/fs/cgroup") == 2) {
1350 bool has_user_slice
= false;
1352 mountpoint
= must_copy_string("/sys/fs/cgroup");
1356 user_slice
= must_make_path(mountpoint
, current_cgroup
, NULL
);
1357 if (cg_systemd_created_user_slice(current_cgroup
, init_cgroup
, user_slice
, uid
))
1358 has_user_slice
= true;
1361 cgv2_add_controller(NULL
, mountpoint
, current_cgroup
, init_cgroup
, has_user_slice
);
1367 f
= fopen("/proc/self/mountinfo", "r");
1371 /* we support simple cgroup mounts and lxcfs mounts */
1372 while (getline(&line
, &len
, f
) != -1) {
1374 bool has_user_slice
= false;
1378 mountpoint
= get_mountpoint(line
);
1382 user_slice
= must_make_path(mountpoint
, current_cgroup
, NULL
);
1383 if (cg_systemd_created_user_slice(current_cgroup
, init_cgroup
, user_slice
, uid
))
1384 has_user_slice
= true;
1387 cgv2_add_controller(NULL
, mountpoint
, current_cgroup
, init_cgroup
, has_user_slice
);
1388 /* Although the unified hierarchy can be mounted multiple times,
1389 * each of those mountpoints will expose identical information.
1390 * So let the first mountpoint we find, win.
1396 lxcfs_debug("Detected cgroupfs v2 hierarchy at mountpoint \"%s\" with "
1397 "current cgroup \"%s\" and init cgroup \"%s\".\n",
1398 mountpoint
, current_cgroup
, init_cgroup
);
1408 /* Detect and store information about mounted cgroupfs v1 hierarchies and the
1409 * cgroupfs v2 hierarchy.
1410 * Detect whether we are on a pure cgroupfs v1, cgroupfs v2, or mixed system,
1411 * where some controllers are mounted into their standard cgroupfs v1 locations
1412 * (/sys/fs/cgroup/<controller>) and others are mounted into the cgroupfs v2
1413 * hierarchy (/sys/fs/cgroup).
1415 static bool cg_init(uid_t uid
, gid_t gid
)
1417 if (!cgv1_init(uid
, gid
))
1420 if (!cgv2_init(uid
, gid
))
1423 if (cgv1_hierarchies
&& cgv2_hierarchies
) {
1424 cg_mount_mode
= CGROUP_MIXED
;
1425 lxcfs_debug("%s\n", "Detected cgroupfs v1 and v2 hierarchies.");
1426 } else if (cgv1_hierarchies
&& !cgv2_hierarchies
) {
1427 cg_mount_mode
= CGROUP_PURE_V1
;
1428 lxcfs_debug("%s\n", "Detected cgroupfs v1 hierarchies.");
1429 } else if (cgv2_hierarchies
&& !cgv1_hierarchies
) {
1430 cg_mount_mode
= CGROUP_PURE_V2
;
1431 lxcfs_debug("%s\n", "Detected cgroupfs v2 hierarchies.");
1433 cg_mount_mode
= CGROUP_UNKNOWN
;
1434 mysyslog(LOG_ERR
, "Could not detect cgroupfs hierarchy.\n", NULL
);
1437 if (cg_mount_mode
== CGROUP_UNKNOWN
)
1443 /* Try to move/migrate us into @cgroup in a cgroupfs v1 hierarchy. */
1444 static bool cgv1_enter(const char *cgroup
)
1446 struct cgv1_hierarchy
**it
;
1448 for (it
= cgv1_hierarchies
; it
&& *it
; it
++) {
1450 bool entered
= false;
1452 if (!(*it
)->controllers
|| !(*it
)->mountpoint
||
1453 !(*it
)->init_cgroup
|| !(*it
)->create_rw_cgroup
)
1456 for (controller
= (*it
)->controllers
; controller
&& *controller
;
1460 /* We've already been placed in a user slice, so we
1461 * don't need to enter the cgroup again.
1463 if ((*it
)->systemd_user_slice
) {
1468 path
= must_make_path((*it
)->mountpoint
,
1473 if (!file_exists(path
)) {
1475 path
= must_make_path((*it
)->mountpoint
,
1481 lxcfs_debug("Attempting to enter cgroupfs v1 hierarchy in \"%s\" cgroup.\n", path
);
1482 entered
= write_int(path
, (int)getpid());
1487 lxcfs_debug("Failed to enter cgroupfs v1 hierarchy in \"%s\" cgroup.\n", path
);
1497 /* Try to move/migrate us into @cgroup in the cgroupfs v2 hierarchy. */
1498 static bool cgv2_enter(const char *cgroup
)
1500 struct cgv2_hierarchy
*v2
;
1502 bool entered
= false;
1504 if (!cgv2_hierarchies
)
1507 v2
= *cgv2_hierarchies
;
1509 if (!v2
->mountpoint
|| !v2
->base_cgroup
)
1512 if (!v2
->create_rw_cgroup
|| v2
->systemd_user_slice
)
1515 path
= must_make_path(v2
->mountpoint
, v2
->base_cgroup
, cgroup
, "/cgroup.procs", NULL
);
1516 lxcfs_debug("Attempting to enter cgroupfs v2 hierarchy in cgroup \"%s\".\n", path
);
1517 entered
= write_int(path
, (int)getpid());
1519 lxcfs_debug("Failed to enter cgroupfs v2 hierarchy in cgroup \"%s\".\n", path
);
1529 /* Wrapper around cgv{1,2}_enter(). */
1530 static bool cg_enter(const char *cgroup
)
1532 if (!cgv1_enter(cgroup
)) {
1533 mysyslog(LOG_WARNING
, "cgroupfs v1: Failed to enter cgroups.\n", NULL
);
1537 if (!cgv2_enter(cgroup
)) {
1538 mysyslog(LOG_WARNING
, "cgroupfs v2: Failed to enter cgroups.\n", NULL
);
1545 /* Escape to root cgroup in all detected cgroupfs v1 hierarchies. */
1546 static void cgv1_escape(void)
1548 struct cgv1_hierarchy
**it
;
1550 /* In case systemd hasn't already placed us in a user slice for the
1551 * cpuset v1 controller we will reside in the root cgroup. This means
1552 * that cgroup.clone_children will not have been initialized for us so
1555 for (it
= cgv1_hierarchies
; it
&& *it
; it
++)
1556 if (!cgv1_handle_root_cpuset_hierarchy(*it
))
1557 mysyslog(LOG_WARNING
, "cgroupfs v1: Failed to initialize cpuset.\n", NULL
);
1559 if (!cgv1_enter("/"))
1560 mysyslog(LOG_WARNING
, "cgroupfs v1: Failed to escape to init's cgroup.\n", NULL
);
1563 /* Escape to root cgroup in the cgroupfs v2 hierarchy. */
1564 static void cgv2_escape(void)
1566 if (!cgv2_enter("/"))
1567 mysyslog(LOG_WARNING
, "cgroupfs v2: Failed to escape to init's cgroup.\n", NULL
);
1570 /* Wrapper around cgv{1,2}_escape(). */
1571 static void cg_escape(void)
1577 /* Get uid and gid for @user. */
1578 static bool get_uid_gid(const char *user
, uid_t
*uid
, gid_t
*gid
)
1580 struct passwd
*pwent
;
1582 pwent
= getpwnam(user
);
1586 *uid
= pwent
->pw_uid
;
1587 *gid
= pwent
->pw_gid
;
1592 /* Check if cgroup belongs to our uid and gid. If so, reuse it. */
1593 static bool cg_belongs_to_uid_gid(const char *path
, uid_t uid
, gid_t gid
)
1595 struct stat statbuf
;
1597 if (stat(path
, &statbuf
) < 0)
1600 if (!(statbuf
.st_uid
== uid
) || !(statbuf
.st_gid
== gid
))
1606 /* Create cpumask from cpulist aka turn:
1614 static uint32_t *cg_cpumask(char *buf
, size_t nbits
)
1617 char *saveptr
= NULL
;
1618 size_t arrlen
= BITS_TO_LONGS(nbits
);
1619 uint32_t *bitarr
= calloc(arrlen
, sizeof(uint32_t));
1623 for (; (token
= strtok_r(buf
, ",", &saveptr
)); buf
= NULL
) {
1625 unsigned start
= strtoul(token
, NULL
, 0);
1626 unsigned end
= start
;
1628 char *range
= strchr(token
, '-');
1630 end
= strtoul(range
+ 1, NULL
, 0);
1631 if (!(start
<= end
)) {
1641 while (start
<= end
)
1642 set_bit(start
++, bitarr
);
1648 static char *string_join(const char *sep
, const char **parts
, bool use_as_prefix
)
1652 size_t sep_len
= strlen(sep
);
1653 size_t result_len
= use_as_prefix
* sep_len
;
1658 /* calculate new string length */
1659 for (p
= (char **)parts
; *p
; p
++)
1660 result_len
+= (p
> (char **)parts
) * sep_len
+ strlen(*p
);
1662 result
= calloc(result_len
+ 1, sizeof(char));
1667 strcpy(result
, sep
);
1668 for (p
= (char **)parts
; *p
; p
++) {
1669 if (p
> (char **)parts
)
1670 strcat(result
, sep
);
1677 /* The largest integer that can fit into long int is 2^64. This is a
1680 #define __IN_TO_STR_LEN 21
1681 /* Turn cpumask into simple, comma-separated cpulist. */
1682 static char *cg_cpumask_to_cpulist(uint32_t *bitarr
, size_t nbits
)
1686 char numstr
[__IN_TO_STR_LEN
] = {0};
1687 char **cpulist
= NULL
;
1689 for (i
= 0; i
<= nbits
; i
++) {
1690 if (is_set(i
, bitarr
)) {
1691 ret
= snprintf(numstr
, __IN_TO_STR_LEN
, "%zu", i
);
1692 if (ret
< 0 || (size_t)ret
>= __IN_TO_STR_LEN
) {
1693 free_string_list(cpulist
);
1696 must_append_string(&cpulist
, numstr
);
1699 return string_join(",", (const char **)cpulist
, false);
1702 static ssize_t
cg_get_max_cpus(char *cpulist
)
1705 char *maxcpus
= cpulist
;
1708 c1
= strrchr(maxcpus
, ',');
1712 c2
= strrchr(maxcpus
, '-');
1721 /* If the above logic is correct, c1 should always hold a valid string
1726 cpus
= strtoul(c1
, NULL
, 0);
1733 static ssize_t
write_nointr(int fd
, const void* buf
, size_t count
)
1737 ret
= write(fd
, buf
, count
);
1738 if (ret
< 0 && errno
== EINTR
)
1743 static int write_to_file(const char *filename
, const void* buf
, size_t count
, bool add_newline
)
1745 int fd
, saved_errno
;
1748 fd
= open(filename
, O_WRONLY
| O_TRUNC
| O_CREAT
| O_CLOEXEC
, 0666);
1751 ret
= write_nointr(fd
, buf
, count
);
1754 if ((size_t)ret
!= count
)
1757 ret
= write_nointr(fd
, "\n", 1);
1765 saved_errno
= errno
;
1767 errno
= saved_errno
;
1771 #define __ISOL_CPUS "/sys/devices/system/cpu/isolated"
1772 static bool cg_filter_and_set_cpus(char *path
, bool am_initialized
)
1774 char *lastslash
, *fpath
, oldv
;
1778 ssize_t maxposs
= 0, maxisol
= 0;
1779 char *cpulist
= NULL
, *posscpus
= NULL
, *isolcpus
= NULL
;
1780 uint32_t *possmask
= NULL
, *isolmask
= NULL
;
1781 bool bret
= false, flipped_bit
= false;
1783 lastslash
= strrchr(path
, '/');
1784 if (!lastslash
) { // bug... this shouldn't be possible
1785 lxcfs_debug("Invalid path: %s.\n", path
);
1790 fpath
= must_make_path(path
, "cpuset.cpus", NULL
);
1791 posscpus
= read_file(fpath
);
1793 lxcfs_debug("Could not read file: %s.\n", fpath
);
1797 /* Get maximum number of cpus found in possible cpuset. */
1798 maxposs
= cg_get_max_cpus(posscpus
);
1802 if (!file_exists(__ISOL_CPUS
)) {
1803 /* This system doesn't expose isolated cpus. */
1804 lxcfs_debug("%s", "Path: "__ISOL_CPUS
" to read isolated cpus from does not exist.\n");
1806 /* No isolated cpus but we weren't already initialized by
1807 * someone. We should simply copy the parents cpuset.cpus
1810 if (!am_initialized
) {
1811 lxcfs_debug("%s", "Copying cpuset of parent cgroup.\n");
1814 /* No isolated cpus but we were already initialized by someone.
1815 * Nothing more to do for us.
1820 isolcpus
= read_file(__ISOL_CPUS
);
1822 lxcfs_debug("%s", "Could not read file "__ISOL_CPUS
"\n");
1825 if (!isdigit(isolcpus
[0])) {
1826 lxcfs_debug("%s", "No isolated cpus detected.\n");
1828 /* No isolated cpus but we weren't already initialized by
1829 * someone. We should simply copy the parents cpuset.cpus
1832 if (!am_initialized
) {
1833 lxcfs_debug("%s", "Copying cpuset of parent cgroup.\n");
1836 /* No isolated cpus but we were already initialized by someone.
1837 * Nothing more to do for us.
1842 /* Get maximum number of cpus found in isolated cpuset. */
1843 maxisol
= cg_get_max_cpus(isolcpus
);
1847 if (maxposs
< maxisol
)
1851 possmask
= cg_cpumask(posscpus
, maxposs
);
1853 lxcfs_debug("%s", "Could not create cpumask for all possible cpus.\n");
1857 isolmask
= cg_cpumask(isolcpus
, maxposs
);
1859 lxcfs_debug("%s", "Could not create cpumask for all isolated cpus.\n");
1863 for (i
= 0; i
<= maxposs
; i
++) {
1864 if (is_set(i
, isolmask
) && is_set(i
, possmask
)) {
1866 clear_bit(i
, possmask
);
1871 lxcfs_debug("%s", "No isolated cpus present in cpuset.\n");
1874 lxcfs_debug("%s", "Removed isolated cpus from cpuset.\n");
1876 cpulist
= cg_cpumask_to_cpulist(possmask
, maxposs
);
1878 lxcfs_debug("%s", "Could not create cpu list.\n");
1884 fpath
= must_make_path(path
, "cpuset.cpus", NULL
);
1885 ret
= write_to_file(fpath
, cpulist
, strlen(cpulist
), false);
1887 lxcfs_debug("Could not write cpu list to: %s.\n", fpath
);
1900 if (posscpus
!= cpulist
)
1908 int read_from_file(const char *filename
, void* buf
, size_t count
)
1910 int fd
= -1, saved_errno
;
1913 fd
= open(filename
, O_RDONLY
| O_CLOEXEC
);
1917 if (!buf
|| !count
) {
1920 while ((ret
= read(fd
, buf2
, 100)) > 0)
1925 memset(buf
, 0, count
);
1926 ret
= read(fd
, buf
, count
);
1930 lxcfs_debug("read %s: %s", filename
, strerror(errno
));
1932 saved_errno
= errno
;
1934 errno
= saved_errno
;
1938 /* Copy contents of parent(@path)/@file to @path/@file */
1939 static bool cg_copy_parent_file(char *path
, char *file
)
1941 char *lastslash
, *value
= NULL
, *fpath
, oldv
;
1945 lastslash
= strrchr(path
, '/');
1946 if (!lastslash
) { // bug... this shouldn't be possible
1947 lxcfs_debug("cgfsng:copy_parent_file: bad path %s", path
);
1952 fpath
= must_make_path(path
, file
, NULL
);
1953 len
= read_from_file(fpath
, NULL
, 0);
1956 value
= must_alloc(len
+ 1);
1957 if (read_from_file(fpath
, value
, len
) != len
)
1961 fpath
= must_make_path(path
, file
, NULL
);
1962 ret
= write_to_file(fpath
, value
, len
, false);
1964 lxcfs_debug("Unable to write %s to %s", value
, fpath
);
1970 lxcfs_debug("Error reading '%s'", fpath
);
1976 /* In case systemd hasn't already placed us in a user slice for the cpuset v1
1977 * controller we will reside in the root cgroup. This means that
1978 * cgroup.clone_children will not have been initialized for us so we need to do
1981 static bool cgv1_handle_root_cpuset_hierarchy(struct cgv1_hierarchy
*h
)
1983 char *clonechildrenpath
, v
;
1985 if (!string_in_list(h
->controllers
, "cpuset"))
1988 clonechildrenpath
= must_make_path(h
->mountpoint
, "cgroup.clone_children", NULL
);
1990 if (read_from_file(clonechildrenpath
, &v
, 1) < 0) {
1991 lxcfs_debug("Failed to read '%s'", clonechildrenpath
);
1992 free(clonechildrenpath
);
1996 if (v
== '1') { /* already set for us by someone else */
1997 free(clonechildrenpath
);
2001 if (write_to_file(clonechildrenpath
, "1", 1, false) < 0) {
2002 /* Set clone_children so children inherit our settings */
2003 lxcfs_debug("Failed to write 1 to %s", clonechildrenpath
);
2004 free(clonechildrenpath
);
2007 free(clonechildrenpath
);
2012 * Initialize the cpuset hierarchy in first directory of @gname and
2013 * set cgroup.clone_children so that children inherit settings.
2014 * Since the h->base_path is populated by init or ourselves, we know
2015 * it is already initialized.
2017 static bool cgv1_handle_cpuset_hierarchy(struct cgv1_hierarchy
*h
,
2020 char *cgpath
, *clonechildrenpath
, v
, *slash
;
2022 if (!string_in_list(h
->controllers
, "cpuset"))
2027 slash
= strchr(cgroup
, '/');
2031 cgpath
= must_make_path(h
->mountpoint
, h
->base_cgroup
, cgroup
, NULL
);
2034 if (mkdir(cgpath
, 0755) < 0 && errno
!= EEXIST
) {
2035 lxcfs_debug("Failed to create '%s'", cgpath
);
2039 clonechildrenpath
= must_make_path(cgpath
, "cgroup.clone_children", NULL
);
2040 if (!file_exists(clonechildrenpath
)) { /* unified hierarchy doesn't have clone_children */
2041 free(clonechildrenpath
);
2045 if (read_from_file(clonechildrenpath
, &v
, 1) < 0) {
2046 lxcfs_debug("Failed to read '%s'", clonechildrenpath
);
2047 free(clonechildrenpath
);
2052 /* Make sure any isolated cpus are removed from cpuset.cpus. */
2053 if (!cg_filter_and_set_cpus(cgpath
, v
== '1')) {
2054 lxcfs_debug("%s", "Failed to remove isolated cpus.\n");
2055 free(clonechildrenpath
);
2060 if (v
== '1') { /* already set for us by someone else */
2061 lxcfs_debug("%s", "\"cgroup.clone_children\" was already set to \"1\".\n");
2062 free(clonechildrenpath
);
2067 /* copy parent's settings */
2068 if (!cg_copy_parent_file(cgpath
, "cpuset.mems")) {
2069 lxcfs_debug("%s", "Failed to copy \"cpuset.mems\" settings.\n");
2071 free(clonechildrenpath
);
2076 if (write_to_file(clonechildrenpath
, "1", 1, false) < 0) {
2077 /* Set clone_children so children inherit our settings */
2078 lxcfs_debug("Failed to write 1 to %s", clonechildrenpath
);
2079 free(clonechildrenpath
);
2082 free(clonechildrenpath
);
2086 /* Create and chown @cgroup for all given controllers in a cgroupfs v1 hierarchy
2087 * (For example, create @cgroup for the cpu and cpuacct controller mounted into
2088 * /sys/fs/cgroup/cpu,cpuacct). Check if the path already exists and report back
2089 * to the caller in @existed.
2091 #define __PAM_CGFS_USER "/user/"
2092 #define __PAM_CGFS_USER_LEN 6
2093 static bool cgv1_create_one(struct cgv1_hierarchy
*h
, const char *cgroup
, uid_t uid
, gid_t gid
, bool *existed
)
2095 char *clean_base_cgroup
, *path
;
2097 struct cgv1_hierarchy
*it
;
2098 bool created
= false;
2102 for (controller
= it
->controllers
; controller
&& *controller
;
2104 if (!cgv1_handle_cpuset_hierarchy(it
, cgroup
))
2107 /* If systemd has already created a cgroup for us, keep using
2110 if (cg_systemd_chown_existing_cgroup(it
->mountpoint
,
2111 it
->base_cgroup
, uid
, gid
,
2112 it
->systemd_user_slice
)) {
2116 /* We need to make sure that we do not create an endless chain
2117 * of sub-cgroups. So we check if we have already logged in
2118 * somehow (sudo -i, su, etc.) and have created a
2119 * /user/PAM_user/idx cgroup. If so, we skip that part. For most
2120 * cgroups this is unnecessary since we use the init_cgroup
2121 * anyway, but for controllers which have an existing systemd
2122 * cgroup that does not match the current uid, this is pretty
2125 if (strncmp(it
->base_cgroup
, __PAM_CGFS_USER
, __PAM_CGFS_USER_LEN
) == 0) {
2126 free(it
->base_cgroup
);
2127 it
->base_cgroup
= must_copy_string("/");
2130 strstr(it
->base_cgroup
, __PAM_CGFS_USER
);
2131 if (clean_base_cgroup
)
2132 *clean_base_cgroup
= '\0';
2135 path
= must_make_path(it
->mountpoint
, it
->init_cgroup
, cgroup
, NULL
);
2136 lxcfs_debug("Constructing path: %s.\n", path
);
2137 if (file_exists(path
)) {
2138 bool our_cg
= cg_belongs_to_uid_gid(path
, uid
, gid
);
2139 lxcfs_debug("%s existed and does %shave our uid: %d and gid: %d.\n", path
, our_cg
? "" : "not ", uid
, gid
);
2147 created
= mkdir_p(it
->mountpoint
, path
);
2152 if (chown(path
, uid
, gid
) < 0)
2153 mysyslog(LOG_WARNING
,
2154 "Failed to chown %s to %d:%d: %s.\n", path
,
2155 (int)uid
, (int)gid
, strerror(errno
), NULL
);
2156 lxcfs_debug("Chowned %s to %d:%d.\n", path
, (int)uid
, (int)gid
);
2164 /* Try to remove @cgroup for all given controllers in a cgroupfs v1 hierarchy
2165 * (For example, try to remove @cgroup for the cpu and cpuacct controller
2166 * mounted into /sys/fs/cgroup/cpu,cpuacct). Ignores failures.
2168 static bool cgv1_remove_one(struct cgv1_hierarchy
*h
, const char *cgroup
)
2173 /* Better safe than sorry. */
2174 if (!h
->controllers
)
2177 /* Cgroups created by systemd for us which we re-use won't be removed
2178 * here, since we're using init_cgroup + cgroup as path instead of
2179 * base_cgroup + cgroup.
2181 path
= must_make_path(h
->mountpoint
, h
->init_cgroup
, cgroup
, NULL
);
2182 (void)recursive_rmdir(path
);
2188 /* Try to remove @cgroup the cgroupfs v2 hierarchy. */
2189 static bool cgv2_remove(const char *cgroup
)
2191 struct cgv2_hierarchy
*v2
;
2194 if (!cgv2_hierarchies
)
2197 v2
= *cgv2_hierarchies
;
2199 /* If we reused an already existing cgroup, don't bother trying to
2200 * remove (a potentially wrong)/the path.
2201 * Cgroups created by systemd for us which we re-use would be removed
2202 * here, since we're using base_cgroup + cgroup as path.
2204 if (v2
->systemd_user_slice
)
2207 path
= must_make_path(v2
->mountpoint
, v2
->base_cgroup
, cgroup
, NULL
);
2208 (void)recursive_rmdir(path
);
2214 /* Create @cgroup in all detected cgroupfs v1 hierarchy. If the creation fails
2215 * for any cgroupfs v1 hierarchy, remove all we have created so far. Report
2216 * back, to the caller if the creation failed due to @cgroup already existing
2219 static bool cgv1_create(const char *cgroup
, uid_t uid
, gid_t gid
, bool *existed
)
2221 struct cgv1_hierarchy
**it
, **rev_it
;
2222 bool all_created
= true;
2224 for (it
= cgv1_hierarchies
; it
&& *it
; it
++) {
2225 if (!(*it
)->controllers
|| !(*it
)->mountpoint
||
2226 !(*it
)->init_cgroup
|| !(*it
)->create_rw_cgroup
)
2229 if (!cgv1_create_one(*it
, cgroup
, uid
, gid
, existed
)) {
2230 all_created
= false;
2238 for (rev_it
= cgv1_hierarchies
; rev_it
&& *rev_it
&& (*rev_it
!= *it
);
2240 cgv1_remove_one(*rev_it
, cgroup
);
2245 /* Create @cgroup in the cgroupfs v2 hierarchy. Report back, to the caller if
2246 * the creation failed due to @cgroup already existing via @existed.
2248 static bool cgv2_create(const char *cgroup
, uid_t uid
, gid_t gid
, bool *existed
)
2250 char *clean_base_cgroup
;
2252 struct cgv2_hierarchy
*v2
;
2253 bool created
= false;
2257 if (!cgv2_hierarchies
|| !(*cgv2_hierarchies
)->create_rw_cgroup
)
2260 v2
= *cgv2_hierarchies
;
2262 /* We can't be placed under init's cgroup for the v2 hierarchy. We need
2263 * to be placed under our current cgroup.
2265 if (cg_systemd_chown_existing_cgroup(v2
->mountpoint
,
2266 v2
->base_cgroup
, uid
, gid
,
2267 v2
->systemd_user_slice
))
2270 /* We need to make sure that we do not create an endless chain of
2271 * sub-cgroups. So we check if we have already logged in somehow (sudo
2272 * -i, su, etc.) and have created a /user/PAM_user/idx cgroup. If so, we
2275 if (strncmp(v2
->base_cgroup
, __PAM_CGFS_USER
, __PAM_CGFS_USER_LEN
) == 0) {
2276 free(v2
->base_cgroup
);
2277 v2
->base_cgroup
= must_copy_string("/");
2279 clean_base_cgroup
= strstr(v2
->base_cgroup
, __PAM_CGFS_USER
);
2280 if (clean_base_cgroup
)
2281 *clean_base_cgroup
= '\0';
2284 path
= must_make_path(v2
->mountpoint
, v2
->base_cgroup
, cgroup
, NULL
);
2285 lxcfs_debug("Constructing path \"%s\".\n", path
);
2286 if (file_exists(path
)) {
2287 bool our_cg
= cg_belongs_to_uid_gid(path
, uid
, gid
);
2288 lxcfs_debug("%s existed and does %shave our uid: %d and gid: %d.\n", path
, our_cg
? "" : "not ", uid
, gid
);
2297 created
= mkdir_p(v2
->mountpoint
, path
);
2303 if (chown(path
, uid
, gid
) < 0)
2304 mysyslog(LOG_WARNING
, "Failed to chown %s to %d:%d: %s.\n",
2305 path
, (int)uid
, (int)gid
, strerror(errno
), NULL
);
2306 lxcfs_debug("Chowned %s to %d:%d.\n", path
, (int)uid
, (int)gid
);
2312 /* Create writeable cgroups for @user at login. Details can be found in the
2313 * preamble/license at the top of this file.
2315 static int handle_login(const char *user
, uid_t uid
, gid_t gid
)
2319 char cg
[MAXPATHLEN
];
2324 ret
= snprintf(cg
, MAXPATHLEN
, "/user/%s/%d", user
, idx
);
2325 if (ret
< 0 || ret
>= MAXPATHLEN
) {
2326 mysyslog(LOG_ERR
, "Username too long.\n", NULL
);
2327 return PAM_SESSION_ERR
;
2331 if (!cgv2_create(cg
, uid
, gid
, &existed
)) {
2337 mysyslog(LOG_ERR
, "Failed to create a cgroup for user %s.\n", user
, NULL
);
2338 return PAM_SESSION_ERR
;
2342 if (!cgv1_create(cg
, uid
, gid
, &existed
)) {
2348 mysyslog(LOG_ERR
, "Failed to create a cgroup for user %s.\n", user
, NULL
);
2349 return PAM_SESSION_ERR
;
2352 if (!cg_enter(cg
)) {
2353 mysyslog( LOG_ERR
, "Failed to enter user cgroup %s for user %s.\n", cg
, user
, NULL
);
2354 return PAM_SESSION_ERR
;
2362 /* Try to prune cgroups we created and that now are empty from all cgroupfs v1
2365 static bool cgv1_prune_empty_cgroups(const char *user
)
2367 bool controller_removed
= true;
2368 bool all_removed
= true;
2369 struct cgv1_hierarchy
**it
;
2371 for (it
= cgv1_hierarchies
; it
&& *it
; it
++) {
2373 char *path_base
, *path_init
;
2376 if (!(*it
)->controllers
|| !(*it
)->mountpoint
||
2377 !(*it
)->init_cgroup
|| !(*it
)->create_rw_cgroup
)
2380 for (controller
= (*it
)->controllers
; controller
&& *controller
;
2382 bool path_base_rm
, path_init_rm
;
2384 path_base
= must_make_path((*it
)->mountpoint
, (*it
)->base_cgroup
, "/user", user
, NULL
);
2385 lxcfs_debug("cgroupfs v1: Trying to prune \"%s\".\n", path_base
);
2386 ret
= recursive_rmdir(path_base
);
2387 if (ret
== -ENOENT
|| ret
>= 0)
2388 path_base_rm
= true;
2390 path_base_rm
= false;
2393 path_init
= must_make_path((*it
)->mountpoint
, (*it
)->init_cgroup
, "/user", user
, NULL
);
2394 lxcfs_debug("cgroupfs v1: Trying to prune \"%s\".\n", path_init
);
2395 ret
= recursive_rmdir(path_init
);
2396 if (ret
== -ENOENT
|| ret
>= 0)
2397 path_init_rm
= true;
2399 path_init_rm
= false;
2402 if (!path_base_rm
&& !path_init_rm
) {
2403 controller_removed
= false;
2407 controller_removed
= true;
2410 if (!controller_removed
)
2411 all_removed
= false;
2417 /* Try to prune cgroup we created and that now is empty from the cgroupfs v2
2420 static bool cgv2_prune_empty_cgroups(const char *user
)
2423 struct cgv2_hierarchy
*v2
;
2424 char *path_base
, *path_init
;
2425 bool path_base_rm
, path_init_rm
;
2427 if (!cgv2_hierarchies
)
2430 v2
= *cgv2_hierarchies
;
2432 path_base
= must_make_path(v2
->mountpoint
, v2
->base_cgroup
, "/user", user
, NULL
);
2433 lxcfs_debug("cgroupfs v2: Trying to prune \"%s\".\n", path_base
);
2434 ret
= recursive_rmdir(path_base
);
2435 if (ret
== -ENOENT
|| ret
>= 0)
2436 path_base_rm
= true;
2438 path_base_rm
= false;
2441 path_init
= must_make_path(v2
->mountpoint
, v2
->init_cgroup
, "/user", user
, NULL
);
2442 lxcfs_debug("cgroupfs v2: Trying to prune \"%s\".\n", path_init
);
2443 ret
= recursive_rmdir(path_init
);
2444 if (ret
== -ENOENT
|| ret
>= 0)
2445 path_init_rm
= true;
2447 path_init_rm
= false;
2450 if (!path_base_rm
&& !path_init_rm
)
2456 /* Wrapper around cgv{1,2}_prune_empty_cgroups(). */
2457 static void cg_prune_empty_cgroups(const char *user
)
2459 (void)cgv1_prune_empty_cgroups(user
);
2460 (void)cgv2_prune_empty_cgroups(user
);
2463 /* Free allocated information for detected cgroupfs v1 hierarchies. */
2464 static void cgv1_free_hierarchies(void)
2466 struct cgv1_hierarchy
**it
;
2468 if (!cgv1_hierarchies
)
2471 for (it
= cgv1_hierarchies
; it
&& *it
; it
++) {
2472 if ((*it
)->controllers
) {
2474 for (tmp
= (*it
)->controllers
; tmp
&& *tmp
; tmp
++)
2477 free((*it
)->controllers
);
2479 free((*it
)->mountpoint
);
2480 free((*it
)->base_cgroup
);
2481 free((*it
)->fullcgpath
);
2482 free((*it
)->init_cgroup
);
2484 free(cgv1_hierarchies
);
2487 /* Free allocated information for the detected cgroupfs v2 hierarchy. */
2488 static void cgv2_free_hierarchies(void)
2490 struct cgv2_hierarchy
**it
;
2492 if (!cgv2_hierarchies
)
2495 for (it
= cgv2_hierarchies
; it
&& *it
; it
++) {
2496 if ((*it
)->controllers
) {
2498 for (tmp
= (*it
)->controllers
; tmp
&& *tmp
; tmp
++)
2501 free((*it
)->controllers
);
2503 free((*it
)->mountpoint
);
2504 free((*it
)->base_cgroup
);
2505 free((*it
)->fullcgpath
);
2506 free((*it
)->init_cgroup
);
2508 free(cgv2_hierarchies
);
2511 /* Wrapper around cgv{1,2}_free_hierarchies(). */
2512 static void cg_exit(void)
2514 cgv1_free_hierarchies();
2515 cgv2_free_hierarchies();
2518 int pam_sm_open_session(pam_handle_t
*pamh
, int flags
, int argc
,
2524 const char *PAM_user
= NULL
;
2526 ret
= pam_get_user(pamh
, &PAM_user
, NULL
);
2527 if (ret
!= PAM_SUCCESS
) {
2528 mysyslog(LOG_ERR
, "PAM-CGFS: couldn't get user\n", NULL
);
2529 return PAM_SESSION_ERR
;
2532 if (!get_uid_gid(PAM_user
, &uid
, &gid
)) {
2533 mysyslog(LOG_ERR
, "Failed to get uid and gid for %s.\n", PAM_user
, NULL
);
2534 return PAM_SESSION_ERR
;
2537 if (!cg_init(uid
, gid
)) {
2538 mysyslog(LOG_ERR
, "Failed to get list of controllers\n", NULL
);
2539 return PAM_SESSION_ERR
;
2542 /* Try to prune cgroups, that are actually empty but were still marked
2543 * as busy by the kernel so we couldn't remove them on session close.
2545 cg_prune_empty_cgroups(PAM_user
);
2547 if (cg_mount_mode
== CGROUP_UNKNOWN
)
2548 return PAM_SESSION_ERR
;
2550 if (argc
> 1 && strcmp(argv
[0], "-c") == 0)
2551 cg_mark_to_make_rw(argv
[1]);
2553 return handle_login(PAM_user
, uid
, gid
);
2556 int pam_sm_close_session(pam_handle_t
*pamh
, int flags
, int argc
,
2562 const char *PAM_user
= NULL
;
2564 ret
= pam_get_user(pamh
, &PAM_user
, NULL
);
2565 if (ret
!= PAM_SUCCESS
) {
2566 mysyslog(LOG_ERR
, "PAM-CGFS: couldn't get user\n", NULL
);
2567 return PAM_SESSION_ERR
;
2570 if (!get_uid_gid(PAM_user
, &uid
, &gid
)) {
2571 mysyslog(LOG_ERR
, "Failed to get uid and gid for %s.\n", PAM_user
, NULL
);
2572 return PAM_SESSION_ERR
;
2575 if (cg_mount_mode
== CGROUP_UNINITIALIZED
) {
2576 if (!cg_init(uid
, gid
))
2577 mysyslog(LOG_ERR
, "Failed to get list of controllers\n", NULL
);
2579 if (argc
> 1 && strcmp(argv
[0], "-c") == 0)
2580 cg_mark_to_make_rw(argv
[1]);
2583 cg_prune_empty_cgroups(PAM_user
);