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