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 <libgen.h> 38 #include <stdbool.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 #include <linux/limits.h> 44 #include <linux/magic.h> 45 #include <sys/mount.h> 46 #include <sys/types.h> 47 #include <sys/vfs.h> 48 49 #include <bpf.h> 50 51 #include "main.h" 52 53 void p_err(const char *fmt, ...) 54 { 55 va_list ap; 56 57 va_start(ap, fmt); 58 if (json_output) { 59 jsonw_start_object(json_wtr); 60 jsonw_name(json_wtr, "error"); 61 jsonw_vprintf_enquote(json_wtr, fmt, ap); 62 jsonw_end_object(json_wtr); 63 } else { 64 fprintf(stderr, "Error: "); 65 vfprintf(stderr, fmt, ap); 66 fprintf(stderr, "\n"); 67 } 68 va_end(ap); 69 } 70 71 void p_info(const char *fmt, ...) 72 { 73 va_list ap; 74 75 if (json_output) 76 return; 77 78 va_start(ap, fmt); 79 vfprintf(stderr, fmt, ap); 80 fprintf(stderr, "\n"); 81 va_end(ap); 82 } 83 84 static bool is_bpffs(char *path) 85 { 86 struct statfs st_fs; 87 88 if (statfs(path, &st_fs) < 0) 89 return false; 90 91 return (unsigned long)st_fs.f_type == BPF_FS_MAGIC; 92 } 93 94 static int mnt_bpffs(const char *target, char *buff, size_t bufflen) 95 { 96 bool bind_done = false; 97 98 while (mount("", target, "none", MS_PRIVATE | MS_REC, NULL)) { 99 if (errno != EINVAL || bind_done) { 100 snprintf(buff, bufflen, 101 "mount --make-private %s failed: %s", 102 target, strerror(errno)); 103 return -1; 104 } 105 106 if (mount(target, target, "none", MS_BIND, NULL)) { 107 snprintf(buff, bufflen, 108 "mount --bind %s %s failed: %s", 109 target, target, strerror(errno)); 110 return -1; 111 } 112 113 bind_done = true; 114 } 115 116 if (mount("bpf", target, "bpf", 0, "mode=0700")) { 117 snprintf(buff, bufflen, "mount -t bpf bpf %s failed: %s", 118 target, strerror(errno)); 119 return -1; 120 } 121 122 return 0; 123 } 124 125 int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type) 126 { 127 enum bpf_obj_type type; 128 int fd; 129 130 fd = bpf_obj_get(path); 131 if (fd < 0) { 132 p_err("bpf obj get (%s): %s", path, 133 errno == EACCES && !is_bpffs(dirname(path)) ? 134 "directory not in bpf file system (bpffs)" : 135 strerror(errno)); 136 return -1; 137 } 138 139 type = get_fd_type(fd); 140 if (type < 0) { 141 close(fd); 142 return type; 143 } 144 if (type != exp_type) { 145 p_err("incorrect object type: %s", get_fd_type_name(type)); 146 close(fd); 147 return -1; 148 } 149 150 return fd; 151 } 152 153 int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32)) 154 { 155 char err_str[ERR_MAX_LEN]; 156 unsigned int id; 157 char *endptr; 158 char *file; 159 char *dir; 160 int err; 161 int fd; 162 163 if (!is_prefix(*argv, "id")) { 164 p_err("expected 'id' got %s", *argv); 165 return -1; 166 } 167 NEXT_ARG(); 168 169 id = strtoul(*argv, &endptr, 0); 170 if (*endptr) { 171 p_err("can't parse %s as ID", *argv); 172 return -1; 173 } 174 NEXT_ARG(); 175 176 if (argc != 1) 177 usage(); 178 179 fd = get_fd_by_id(id); 180 if (fd < 0) { 181 p_err("can't get prog by id (%u): %s", id, strerror(errno)); 182 return -1; 183 } 184 185 err = bpf_obj_pin(fd, *argv); 186 if (!err) 187 goto out_close; 188 189 file = malloc(strlen(*argv) + 1); 190 strcpy(file, *argv); 191 dir = dirname(file); 192 193 if (errno != EPERM || is_bpffs(dir)) { 194 p_err("can't pin the object (%s): %s", *argv, strerror(errno)); 195 goto out_free; 196 } 197 198 /* Attempt to mount bpffs, then retry pinning. */ 199 err = mnt_bpffs(dir, err_str, ERR_MAX_LEN); 200 if (!err) { 201 err = bpf_obj_pin(fd, *argv); 202 if (err) 203 p_err("can't pin the object (%s): %s", *argv, 204 strerror(errno)); 205 } else { 206 err_str[ERR_MAX_LEN - 1] = '\0'; 207 p_err("can't mount BPF file system to pin the object (%s): %s", 208 *argv, err_str); 209 } 210 211 out_free: 212 free(file); 213 out_close: 214 close(fd); 215 return err; 216 } 217 218 const char *get_fd_type_name(enum bpf_obj_type type) 219 { 220 static const char * const names[] = { 221 [BPF_OBJ_UNKNOWN] = "unknown", 222 [BPF_OBJ_PROG] = "prog", 223 [BPF_OBJ_MAP] = "map", 224 }; 225 226 if (type < 0 || type >= ARRAY_SIZE(names) || !names[type]) 227 return names[BPF_OBJ_UNKNOWN]; 228 229 return names[type]; 230 } 231 232 int get_fd_type(int fd) 233 { 234 char path[PATH_MAX]; 235 char buf[512]; 236 ssize_t n; 237 238 snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd); 239 240 n = readlink(path, buf, sizeof(buf)); 241 if (n < 0) { 242 p_err("can't read link type: %s", strerror(errno)); 243 return -1; 244 } 245 if (n == sizeof(path)) { 246 p_err("can't read link type: path too long!"); 247 return -1; 248 } 249 250 if (strstr(buf, "bpf-map")) 251 return BPF_OBJ_MAP; 252 else if (strstr(buf, "bpf-prog")) 253 return BPF_OBJ_PROG; 254 255 return BPF_OBJ_UNKNOWN; 256 } 257 258 char *get_fdinfo(int fd, const char *key) 259 { 260 char path[PATH_MAX]; 261 char *line = NULL; 262 size_t line_n = 0; 263 ssize_t n; 264 FILE *fdi; 265 266 snprintf(path, sizeof(path), "/proc/%d/fdinfo/%d", getpid(), fd); 267 268 fdi = fopen(path, "r"); 269 if (!fdi) { 270 p_err("can't open fdinfo: %s", strerror(errno)); 271 return NULL; 272 } 273 274 while ((n = getline(&line, &line_n, fdi))) { 275 char *value; 276 int len; 277 278 if (!strstr(line, key)) 279 continue; 280 281 fclose(fdi); 282 283 value = strchr(line, '\t'); 284 if (!value || !value[1]) { 285 p_err("malformed fdinfo!?"); 286 free(line); 287 return NULL; 288 } 289 value++; 290 291 len = strlen(value); 292 memmove(line, value, len); 293 line[len - 1] = '\0'; 294 295 return line; 296 } 297 298 p_err("key '%s' not found in fdinfo", key); 299 free(line); 300 fclose(fdi); 301 return NULL; 302 } 303 304 void print_hex_data_json(uint8_t *data, size_t len) 305 { 306 unsigned int i; 307 308 jsonw_start_array(json_wtr); 309 for (i = 0; i < len; i++) 310 jsonw_printf(json_wtr, "\"0x%02hhx\"", data[i]); 311 jsonw_end_array(json_wtr); 312 } 313