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/types.h> 46 #include <sys/vfs.h> 47 48 #include <bpf.h> 49 50 #include "main.h" 51 52 static bool is_bpffs(char *path) 53 { 54 struct statfs st_fs; 55 56 if (statfs(path, &st_fs) < 0) 57 return false; 58 59 return (unsigned long)st_fs.f_type == BPF_FS_MAGIC; 60 } 61 62 int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type) 63 { 64 enum bpf_obj_type type; 65 int fd; 66 67 fd = bpf_obj_get(path); 68 if (fd < 0) { 69 err("bpf obj get (%s): %s\n", path, 70 errno == EACCES && !is_bpffs(dirname(path)) ? 71 "directory not in bpf file system (bpffs)" : 72 strerror(errno)); 73 return -1; 74 } 75 76 type = get_fd_type(fd); 77 if (type < 0) { 78 close(fd); 79 return type; 80 } 81 if (type != exp_type) { 82 err("incorrect object type: %s\n", get_fd_type_name(type)); 83 close(fd); 84 return -1; 85 } 86 87 return fd; 88 } 89 90 int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32)) 91 { 92 unsigned int id; 93 char *endptr; 94 int err; 95 int fd; 96 97 if (!is_prefix(*argv, "id")) { 98 err("expected 'id' got %s\n", *argv); 99 return -1; 100 } 101 NEXT_ARG(); 102 103 id = strtoul(*argv, &endptr, 0); 104 if (*endptr) { 105 err("can't parse %s as ID\n", *argv); 106 return -1; 107 } 108 NEXT_ARG(); 109 110 if (argc != 1) 111 usage(); 112 113 fd = get_fd_by_id(id); 114 if (fd < 0) { 115 err("can't get prog by id (%u): %s\n", id, strerror(errno)); 116 return -1; 117 } 118 119 err = bpf_obj_pin(fd, *argv); 120 close(fd); 121 if (err) { 122 err("can't pin the object (%s): %s\n", *argv, 123 errno == EACCES && !is_bpffs(dirname(*argv)) ? 124 "directory not in bpf file system (bpffs)" : 125 strerror(errno)); 126 return -1; 127 } 128 129 return 0; 130 } 131 132 const char *get_fd_type_name(enum bpf_obj_type type) 133 { 134 static const char * const names[] = { 135 [BPF_OBJ_UNKNOWN] = "unknown", 136 [BPF_OBJ_PROG] = "prog", 137 [BPF_OBJ_MAP] = "map", 138 }; 139 140 if (type < 0 || type >= ARRAY_SIZE(names) || !names[type]) 141 return names[BPF_OBJ_UNKNOWN]; 142 143 return names[type]; 144 } 145 146 int get_fd_type(int fd) 147 { 148 char path[PATH_MAX]; 149 char buf[512]; 150 ssize_t n; 151 152 snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd); 153 154 n = readlink(path, buf, sizeof(buf)); 155 if (n < 0) { 156 err("can't read link type: %s\n", strerror(errno)); 157 return -1; 158 } 159 if (n == sizeof(path)) { 160 err("can't read link type: path too long!\n"); 161 return -1; 162 } 163 164 if (strstr(buf, "bpf-map")) 165 return BPF_OBJ_MAP; 166 else if (strstr(buf, "bpf-prog")) 167 return BPF_OBJ_PROG; 168 169 return BPF_OBJ_UNKNOWN; 170 } 171 172 char *get_fdinfo(int fd, const char *key) 173 { 174 char path[PATH_MAX]; 175 char *line = NULL; 176 size_t line_n = 0; 177 ssize_t n; 178 FILE *fdi; 179 180 snprintf(path, sizeof(path), "/proc/%d/fdinfo/%d", getpid(), fd); 181 182 fdi = fopen(path, "r"); 183 if (!fdi) { 184 err("can't open fdinfo: %s\n", strerror(errno)); 185 return NULL; 186 } 187 188 while ((n = getline(&line, &line_n, fdi))) { 189 char *value; 190 int len; 191 192 if (!strstr(line, key)) 193 continue; 194 195 fclose(fdi); 196 197 value = strchr(line, '\t'); 198 if (!value || !value[1]) { 199 err("malformed fdinfo!?\n"); 200 free(line); 201 return NULL; 202 } 203 value++; 204 205 len = strlen(value); 206 memmove(line, value, len); 207 line[len - 1] = '\0'; 208 209 return line; 210 } 211 212 err("key '%s' not found in fdinfo\n", key); 213 free(line); 214 fclose(fdi); 215 return NULL; 216 } 217