src/cgroups/cgroup2_devices.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 /* Parts of this taken from systemd's implementation. */
   4
   5 #ifndef __LXC_CGROUP2_DEVICES_H
   6 #define __LXC_CGROUP2_DEVICES_H
   7
   8 #ifndef _GNU_SOURCE
   9 #define _GNU_SOURCE
  10 #endif
  11
  12 #ifndef FUSE_USE_VERSION
  13 #define FUSE_USE_VERSION 26
  14 #endif
  15
  16 #define _FILE_OFFSET_BITS 64
  17
  18 #include <errno.h>
  19 #include <fcntl.h>
  20 #include <stdbool.h>
  21 #include <stddef.h>
  22 #include <stdint.h>
  23 #include <sys/stat.h>
  24 #include <sys/syscall.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27
  28 #ifdef HAVE_STRUCT_BPF_CGROUP_DEV_CTX
  29 #include <linux/bpf.h>
  30 #include <linux/filter.h>
  31 #endif
  32
  33 #if !HAVE_BPF
  34 #if !(defined __NR_bpf && __NR_bpf > 0)
  35 #if defined __NR_bpf
  36 #undef __NR_bpf
  37 #endif
  38 #if defined __i386__
  39 #define __NR_bpf 357
  40 #elif defined __x86_64__
  41 #define __NR_bpf 321
  42 #elif defined __aarch64__
  43 #define __NR_bpf 280
  44 #elif defined __arm__
  45 #define __NR_bpf 386
  46 #elif defined __sparc__
  47 #define __NR_bpf 349
  48 #elif defined __s390__
  49 #define __NR_bpf 351
  50 #elif defined __tilegx__
  51 #define __NR_bpf 280
  52 #else
  53 #warning "__NR_bpf not defined for your architecture"
  54 #endif
  55 #endif
  56
  57 union bpf_attr;
  58
  59 static inline int missing_bpf(int cmd, union bpf_attr *attr, size_t size)
  60 {
  61 #ifdef __NR_bpf
  62         return (int)syscall(__NR_bpf, cmd, attr, size);
  63 #else
  64         errno = ENOSYS;
  65         return -1;
  66 #endif
  67 }
  68
  69 #define bpf missing_bpf
  70 #endif
  71
  72 struct bpf_program {
  73         int device_list_type;
  74         int kernel_fd;
  75         uint32_t prog_type;
  76
  77         size_t n_instructions;
  78 #ifdef HAVE_STRUCT_BPF_CGROUP_DEV_CTX
  79         struct bpf_insn *instructions;
  80 #endif
  81
  82         char *attached_path;
  83         int attached_type;
  84         uint32_t attached_flags;
  85 };
  86
  87 #ifdef HAVE_STRUCT_BPF_CGROUP_DEV_CTX
  88 struct bpf_program *bpf_program_new(uint32_t prog_type);
  89 int bpf_program_init(struct bpf_program *prog);
  90 int bpf_program_append_device(struct bpf_program *prog,
  91                               struct device_item *device);
  92 int bpf_program_finalize(struct bpf_program *prog);
  93 int bpf_program_cgroup_attach(struct bpf_program *prog, int type,
  94                               const char *path, uint32_t flags);
  95 int bpf_program_cgroup_detach(struct bpf_program *prog);
  96 void bpf_program_free(struct bpf_program *prog);
  97 bool bpf_devices_cgroup_supported(void);
  98 static inline void __auto_bpf_program_free__(struct bpf_program **prog)
  99 {
 100         if (*prog) {
 101                 bpf_program_free(*prog);
 102                 *prog = NULL;
 103         }
 104 }
 105 #else
 106 static inline struct bpf_program *bpf_program_new(uint32_t prog_type)
 107 {
 108         errno = ENOSYS;
 109         return NULL;
 110 }
 111
 112 static inline int bpf_program_init(struct bpf_program *prog)
 113 {
 114         errno = ENOSYS;
 115         return -1;
 116 }
 117
 118 static inline int bpf_program_append_device(struct bpf_program *prog, char type,
 119                                             int major, int minor,
 120                                             const char *access, int allow)
 121 {
 122         errno = ENOSYS;
 123         return -1;
 124 }
 125
 126 static inline int bpf_program_finalize(struct bpf_program *prog)
 127 {
 128         errno = ENOSYS;
 129         return -1;
 130 }
 131
 132 static inline int bpf_program_cgroup_attach(struct bpf_program *prog, int type,
 133                                             const char *path, uint32_t flags)
 134 {
 135         errno = ENOSYS;
 136         return -1;
 137 }
 138
 139 static inline int bpf_program_cgroup_detach(struct bpf_program *prog)
 140 {
 141         errno = ENOSYS;
 142         return -1;
 143 }
 144
 145 static inline void bpf_program_free(struct bpf_program *prog)
 146 {
 147 }
 148
 149
 150 static inline bool bpf_devices_cgroup_supported(void)
 151 {
 152         return false;
 153 }
 154
 155 static inline void __auto_bpf_program_free__(struct bpf_program **prog)
 156 {
 157 }
 158
 159 #endif
 160
 161 #define __do_bpf_program_free \
 162         __attribute__((__cleanup__(__auto_bpf_program_free__)))
 163
 164 #endif /* __LXC_CGROUP2_DEVICES_H */