1 /* 2 * Copyright (C) 2017 Netronome Systems, Inc. 3 * 4 * This software is dual licensed under the GNU General License Version 2, 5 * June 1991 as shown in the file COPYING in the top-level directory of this 6 * source tree or the BSD 2-Clause License provided below. You have the 7 * option to license this software under the complete terms of either license. 8 * 9 * The BSD 2-Clause License: 10 * 11 * Redistribution and use in source and binary forms, with or 12 * without modification, are permitted provided that the following 13 * conditions are met: 14 * 15 * 1. Redistributions of source code must retain the above 16 * copyright notice, this list of conditions and the following 17 * disclaimer. 18 * 19 * 2. Redistributions in binary form must reproduce the above 20 * copyright notice, this list of conditions and the following 21 * disclaimer in the documentation and/or other materials 22 * provided with the distribution. 23 * 24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 31 * SOFTWARE. 32 */ 33 34 /* Author: Jakub Kicinski <kubakici@wp.pl> */ 35 36 #include <errno.h> 37 #include <fts.h> 38 #include <libgen.h> 39 #include <mntent.h> 40 #include <stdbool.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 #include <linux/limits.h> 46 #include <linux/magic.h> 47 #include <sys/mount.h> 48 #include <sys/types.h> 49 #include <sys/vfs.h> 50 51 #include <bpf.h> 52 53 #include "main.h" 54 55 void p_err(const char *fmt, ...) 56 { 57 va_list ap; 58 59 va_start(ap, fmt); 60 if (json_output) { 61 jsonw_start_object(json_wtr); 62 jsonw_name(json_wtr, "error"); 63 jsonw_vprintf_enquote(json_wtr, fmt, ap); 64 jsonw_end_object(json_wtr); 65 } else { 66 fprintf(stderr, "Error: "); 67 vfprintf(stderr, fmt, ap); 68 fprintf(stderr, "\n"); 69 } 70 va_end(ap); 71 } 72 73 void p_info(const char *fmt, ...) 74 { 75 va_list ap; 76 77 if (json_output) 78 return; 79 80 va_start(ap, fmt); 81 vfprintf(stderr, fmt, ap); 82 fprintf(stderr, "\n"); 83 va_end(ap); 84 } 85 86 static bool is_bpffs(char *path) 87 { 88 struct statfs st_fs; 89 90 if (statfs(path, &st_fs) < 0) 91 return false; 92 93 return (unsigned long)st_fs.f_type == BPF_FS_MAGIC; 94 } 95 96 static int mnt_bpffs(const char *target, char *buff, size_t bufflen) 97 { 98 bool bind_done = false; 99 100 while (mount("", target, "none", MS_PRIVATE | MS_REC, NULL)) { 101 if (errno != EINVAL || bind_done) { 102 snprintf(buff, bufflen, 103 "mount --make-private %s failed: %s", 104 target, strerror(errno)); 105 return -1; 106 } 107 108 if (mount(target, target, "none", MS_BIND, NULL)) { 109 snprintf(buff, bufflen, 110 "mount --bind %s %s failed: %s", 111 target, target, strerror(errno)); 112 return -1; 113 } 114 115 bind_done = true; 116 } 117 118 if (mount("bpf", target, "bpf", 0, "mode=0700")) { 119 snprintf(buff, bufflen, "mount -t bpf bpf %s failed: %s", 120 target, strerror(errno)); 121 return -1; 122 } 123 124 return 0; 125 } 126 127 int open_obj_pinned(char *path) 128 { 129 int fd; 130 131 fd = bpf_obj_get(path); 132 if (fd < 0) { 133 p_err("bpf obj get (%s): %s", path, 134 errno == EACCES && !is_bpffs(dirname(path)) ? 135 "directory not in bpf file system (bpffs)" : 136 strerror(errno)); 137 return -1; 138 } 139 140 return fd; 141 } 142 143 int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type) 144 { 145 enum bpf_obj_type type; 146 int fd; 147 148 fd = open_obj_pinned(path); 149 if (fd < 0) 150 return -1; 151 152 type = get_fd_type(fd); 153 if (type < 0) { 154 close(fd); 155 return type; 156 } 157 if (type != exp_type) { 158 p_err("incorrect object type: %s", get_fd_type_name(type)); 159 close(fd); 160 return -1; 161 } 162 163 return fd; 164 } 165 166 int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32)) 167 { 168 char err_str[ERR_MAX_LEN]; 169 unsigned int id; 170 char *endptr; 171 char *file; 172 char *dir; 173 int err; 174 int fd; 175 176 if (!is_prefix(*argv, "id")) { 177 p_err("expected 'id' got %s", *argv); 178 return -1; 179 } 180 NEXT_ARG(); 181 182 id = strtoul(*argv, &endptr, 0); 183 if (*endptr) { 184 p_err("can't parse %s as ID", *argv); 185 return -1; 186 } 187 NEXT_ARG(); 188 189 if (argc != 1) 190 usage(); 191 192 fd = get_fd_by_id(id); 193 if (fd < 0) { 194 p_err("can't get prog by id (%u): %s", id, strerror(errno)); 195 return -1; 196 } 197 198 err = bpf_obj_pin(fd, *argv); 199 if (!err) 200 goto out_close; 201 202 file = malloc(strlen(*argv) + 1); 203 strcpy(file, *argv); 204 dir = dirname(file); 205 206 if (errno != EPERM || is_bpffs(dir)) { 207 p_err("can't pin the object (%s): %s", *argv, strerror(errno)); 208 goto out_free; 209 } 210 211 /* Attempt to mount bpffs, then retry pinning. */ 212 err = mnt_bpffs(dir, err_str, ERR_MAX_LEN); 213 if (!err) { 214 err = bpf_obj_pin(fd, *argv); 215 if (err) 216 p_err("can't pin the object (%s): %s", *argv, 217 strerror(errno)); 218 } else { 219 err_str[ERR_MAX_LEN - 1] = '\0'; 220 p_err("can't mount BPF file system to pin the object (%s): %s", 221 *argv, err_str); 222 } 223 224 out_free: 225 free(file); 226 out_close: 227 close(fd); 228 return err; 229 } 230 231 const char *get_fd_type_name(enum bpf_obj_type type) 232 { 233 static const char * const names[] = { 234 [BPF_OBJ_UNKNOWN] = "unknown", 235 [BPF_OBJ_PROG] = "prog", 236 [BPF_OBJ_MAP] = "map", 237 }; 238 239 if (type < 0 || type >= ARRAY_SIZE(names) || !names[type]) 240 return names[BPF_OBJ_UNKNOWN]; 241 242 return names[type]; 243 } 244 245 int get_fd_type(int fd) 246 { 247 char path[PATH_MAX]; 248 char buf[512]; 249 ssize_t n; 250 251 snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd); 252 253 n = readlink(path, buf, sizeof(buf)); 254 if (n < 0) { 255 p_err("can't read link type: %s", strerror(errno)); 256 return -1; 257 } 258 if (n == sizeof(path)) { 259 p_err("can't read link type: path too long!"); 260 return -1; 261 } 262 263 if (strstr(buf, "bpf-map")) 264 return BPF_OBJ_MAP; 265 else if (strstr(buf, "bpf-prog")) 266 return BPF_OBJ_PROG; 267 268 return BPF_OBJ_UNKNOWN; 269 } 270 271 char *get_fdinfo(int fd, const char *key) 272 { 273 char path[PATH_MAX]; 274 char *line = NULL; 275 size_t line_n = 0; 276 ssize_t n; 277 FILE *fdi; 278 279 snprintf(path, sizeof(path), "/proc/%d/fdinfo/%d", getpid(), fd); 280 281 fdi = fopen(path, "r"); 282 if (!fdi) { 283 p_err("can't open fdinfo: %s", strerror(errno)); 284 return NULL; 285 } 286 287 while ((n = getline(&line, &line_n, fdi))) { 288 char *value; 289 int len; 290 291 if (!strstr(line, key)) 292 continue; 293 294 fclose(fdi); 295 296 value = strchr(line, '\t'); 297 if (!value || !value[1]) { 298 p_err("malformed fdinfo!?"); 299 free(line); 300 return NULL; 301 } 302 value++; 303 304 len = strlen(value); 305 memmove(line, value, len); 306 line[len - 1] = '\0'; 307 308 return line; 309 } 310 311 p_err("key '%s' not found in fdinfo", key); 312 free(line); 313 fclose(fdi); 314 return NULL; 315 } 316 317 void print_hex_data_json(uint8_t *data, size_t len) 318 { 319 unsigned int i; 320 321 jsonw_start_array(json_wtr); 322 for (i = 0; i < len; i++) 323 jsonw_printf(json_wtr, "\"0x%02hhx\"", data[i]); 324 jsonw_end_array(json_wtr); 325 } 326 327 int build_pinned_obj_table(struct pinned_obj_table *tab, 328 enum bpf_obj_type type) 329 { 330 struct bpf_prog_info pinned_info = {}; 331 struct pinned_obj *obj_node = NULL; 332 __u32 len = sizeof(pinned_info); 333 struct mntent *mntent = NULL; 334 enum bpf_obj_type objtype; 335 FILE *mntfile = NULL; 336 FTSENT *ftse = NULL; 337 FTS *fts = NULL; 338 int fd, err; 339 340 mntfile = setmntent("/proc/mounts", "r"); 341 if (!mntfile) 342 return -1; 343 344 while ((mntent = getmntent(mntfile))) { 345 char *path[] = { mntent->mnt_dir, NULL }; 346 347 if (strncmp(mntent->mnt_type, "bpf", 3) != 0) 348 continue; 349 350 fts = fts_open(path, 0, NULL); 351 if (!fts) 352 continue; 353 354 while ((ftse = fts_read(fts))) { 355 if (!(ftse->fts_info & FTS_F)) 356 continue; 357 fd = open_obj_pinned(ftse->fts_path); 358 if (fd < 0) 359 continue; 360 361 objtype = get_fd_type(fd); 362 if (objtype != type) { 363 close(fd); 364 continue; 365 } 366 memset(&pinned_info, 0, sizeof(pinned_info)); 367 err = bpf_obj_get_info_by_fd(fd, &pinned_info, &len); 368 if (err) { 369 close(fd); 370 continue; 371 } 372 373 obj_node = malloc(sizeof(*obj_node)); 374 if (!obj_node) { 375 close(fd); 376 fts_close(fts); 377 fclose(mntfile); 378 return -1; 379 } 380 381 memset(obj_node, 0, sizeof(*obj_node)); 382 obj_node->id = pinned_info.id; 383 obj_node->path = strdup(ftse->fts_path); 384 hash_add(tab->table, &obj_node->hash, obj_node->id); 385 386 close(fd); 387 } 388 fts_close(fts); 389 } 390 fclose(mntfile); 391 return 0; 392 } 393 394 void delete_pinned_obj_table(struct pinned_obj_table *tab) 395 { 396 struct pinned_obj *obj; 397 struct hlist_node *tmp; 398 unsigned int bkt; 399 400 hash_for_each_safe(tab->table, bkt, tmp, obj, hash) { 401 hash_del(&obj->hash); 402 free(obj->path); 403 free(obj); 404 } 405 } 406