src/cgroups/cgroup_utils.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #ifndef __LXC_CGROUP_UTILS_H
   4 #define __LXC_CGROUP_UTILS_H
   5
   6 #ifndef _GNU_SOURCE
   7 #define _GNU_SOURCE
   8 #endif
   9
  10 #ifndef FUSE_USE_VERSION
  11 #define FUSE_USE_VERSION 26
  12 #endif
  13
  14 #define _FILE_OFFSET_BITS 64
  15
  16 #include <fcntl.h>
  17 #include <stdarg.h>
  18 #include <stdbool.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <sys/mount.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include <sys/vfs.h>
  26 #include <unistd.h>
  27
  28 #include "../config.h"
  29 #include "../macro.h"
  30 #include "../memory_utils.h"
  31
  32 /* Retrieve the cgroup version of a given entry from /proc/<pid>/mountinfo. */
  33 extern int get_cgroup_version(char *line);
  34
  35 /* Check if given entry from /proc/<pid>/mountinfo is a cgroupfs v1 mount. */
  36 extern bool is_cgroupfs_v1(char *line);
  37
  38 /* Check if given entry from /proc/<pid>/mountinfo is a cgroupfs v2 mount. */
  39 extern bool is_cgroupfs_v2(char *line);
  40
  41 /* Given a v1 hierarchy @mountpoint and base @path, verify that we can create
  42  * directories underneath it.
  43  */
  44 extern bool test_writeable_v1(char *mountpoint, char *path);
  45
  46 /* Given a v2 hierarchy @mountpoint and base @path, verify that we can create
  47  * directories underneath it and that we have write access to the cgroup's
  48  * "cgroup.procs" file.
  49  */
  50 extern bool test_writeable_v2(char *mountpoint, char *path);
  51
  52 extern int unified_cgroup_hierarchy(void);
  53
  54 extern void *must_realloc(void *orig, size_t sz);
  55
  56 extern char *must_make_path(const char *first, ...);
  57
  58 extern char *must_copy_string(const char *entry);
  59
  60 /* __typeof__ should be safe to use with all compilers. */
  61 typedef __typeof__(((struct statfs *)NULL)->f_type) fs_type_magic;
  62 extern bool is_fs_type(const struct statfs *fs, fs_type_magic magic_val);
  63
  64 extern char *lxc_string_join(const char *sep, const char **parts,
  65                              bool use_as_prefix);
  66 extern int lxc_count_file_lines(const char *fn);
  67
  68 extern bool dir_exists(const char *path);
  69
  70 extern int safe_mount(const char *src, const char *dest, const char *fstype,
  71                       unsigned long flags, const void *data, const char *rootfs);
  72
  73 #if !HAVE_STRLCPY
  74 extern size_t strlcpy(char *, const char *, size_t);
  75 #endif
  76
  77 #if !HAVE_STRLCAT
  78 extern size_t strlcat(char *d, const char *s, size_t n);
  79 #endif
  80
  81 extern FILE *fopen_cloexec(const char *path, const char *mode);
  82 extern void append_line(char **dest, size_t oldlen, char *new, size_t newlen);
  83 extern char *read_file(const char *fnam);
  84 extern char *readat_file(int fd, const char *path);
  85 extern char *read_file_strip_newline(const char *fnam);
  86 extern char *cg_unified_get_current_cgroup(pid_t pid);
  87 extern char *cg_hybrid_get_current_cgroup(char *basecginfo,
  88                                           const char *controller, int type);
  89 extern char *cg_legacy_get_current_cgroup(pid_t pid, const char *controller);
  90 extern bool mkdir_p(const char *dir, mode_t mode);
  91 extern bool is_cgroup_fd(int fd);
  92
  93 static inline int openat_safe(int fd, const char *path)
  94 {
  95         return openat(fd, path, O_DIRECTORY | O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
  96 }
  97
  98 extern int cgroup_walkup_to_root(int cgroup2_root_fd, int hierarchy_fd,
  99                                  const char *cgroup, const char *file,
 100                                  char **value);
 101
 102 #define must_make_path_relative(__first__, ...)                                \
 103         ({                                                                     \
 104                 char *__ptr__;                                                 \
 105                 if (*__first__ == '/')                                         \
 106                         __ptr__ = must_make_path(".", __first__, __VA_ARGS__); \
 107                 else                                                           \
 108                         __ptr__ = must_make_path(__first__, __VA_ARGS__);      \
 109                 __ptr__;                                                       \
 110         })
 111
 112 static inline bool is_empty_string(const char *s)
 113 {
 114         return !s || strcmp(s, "") == 0;
 115 }
 116
 117 #endif /* __LXC_CGROUP_UTILS_H */