1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 /* Copyright (C) 2020 Facebook */ 3 #include <errno.h> 4 #include <linux/err.h> 5 #include <stdbool.h> 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <string.h> 9 #include <unistd.h> 10 11 #include <bpf/bpf.h> 12 #include <bpf/hashmap.h> 13 14 #include "main.h" 15 #include "skeleton/pid_iter.h" 16 17 #ifdef BPFTOOL_WITHOUT_SKELETONS 18 19 int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type) 20 { 21 return -ENOTSUP; 22 } 23 void delete_obj_refs_table(struct hashmap *map) {} 24 void emit_obj_refs_plain(struct hashmap *map, __u32 id, const char *prefix) {} 25 void emit_obj_refs_json(struct hashmap *map, __u32 id, json_writer_t *json_writer) {} 26 27 #else /* BPFTOOL_WITHOUT_SKELETONS */ 28 29 #include "pid_iter.skel.h" 30 31 static void add_ref(struct hashmap *map, struct pid_iter_entry *e) 32 { 33 struct hashmap_entry *entry; 34 struct obj_refs *refs; 35 struct obj_ref *ref; 36 int err, i; 37 void *tmp; 38 39 hashmap__for_each_key_entry(map, entry, u32_as_hash_field(e->id)) { 40 refs = entry->value; 41 42 for (i = 0; i < refs->ref_cnt; i++) { 43 if (refs->refs[i].pid == e->pid) 44 return; 45 } 46 47 tmp = realloc(refs->refs, (refs->ref_cnt + 1) * sizeof(*ref)); 48 if (!tmp) { 49 p_err("failed to re-alloc memory for ID %u, PID %d, COMM %s...", 50 e->id, e->pid, e->comm); 51 return; 52 } 53 refs->refs = tmp; 54 ref = &refs->refs[refs->ref_cnt]; 55 ref->pid = e->pid; 56 memcpy(ref->comm, e->comm, sizeof(ref->comm)); 57 refs->ref_cnt++; 58 59 return; 60 } 61 62 /* new ref */ 63 refs = calloc(1, sizeof(*refs)); 64 if (!refs) { 65 p_err("failed to alloc memory for ID %u, PID %d, COMM %s...", 66 e->id, e->pid, e->comm); 67 return; 68 } 69 70 refs->refs = malloc(sizeof(*refs->refs)); 71 if (!refs->refs) { 72 free(refs); 73 p_err("failed to alloc memory for ID %u, PID %d, COMM %s...", 74 e->id, e->pid, e->comm); 75 return; 76 } 77 ref = &refs->refs[0]; 78 ref->pid = e->pid; 79 memcpy(ref->comm, e->comm, sizeof(ref->comm)); 80 refs->ref_cnt = 1; 81 refs->has_bpf_cookie = e->has_bpf_cookie; 82 refs->bpf_cookie = e->bpf_cookie; 83 84 err = hashmap__append(map, u32_as_hash_field(e->id), refs); 85 if (err) 86 p_err("failed to append entry to hashmap for ID %u: %s", 87 e->id, strerror(errno)); 88 } 89 90 static int __printf(2, 0) 91 libbpf_print_none(__maybe_unused enum libbpf_print_level level, 92 __maybe_unused const char *format, 93 __maybe_unused va_list args) 94 { 95 return 0; 96 } 97 98 int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type) 99 { 100 struct pid_iter_entry *e; 101 char buf[4096 / sizeof(*e) * sizeof(*e)]; 102 struct pid_iter_bpf *skel; 103 int err, ret, fd = -1, i; 104 libbpf_print_fn_t default_print; 105 106 *map = hashmap__new(hash_fn_for_key_as_id, equal_fn_for_key_as_id, NULL); 107 if (IS_ERR(*map)) { 108 p_err("failed to create hashmap for PID references"); 109 return -1; 110 } 111 set_max_rlimit(); 112 113 skel = pid_iter_bpf__open(); 114 if (!skel) { 115 p_err("failed to open PID iterator skeleton"); 116 return -1; 117 } 118 119 skel->rodata->obj_type = type; 120 121 /* we don't want output polluted with libbpf errors if bpf_iter is not 122 * supported 123 */ 124 default_print = libbpf_set_print(libbpf_print_none); 125 err = pid_iter_bpf__load(skel); 126 libbpf_set_print(default_print); 127 if (err) { 128 /* too bad, kernel doesn't support BPF iterators yet */ 129 err = 0; 130 goto out; 131 } 132 err = pid_iter_bpf__attach(skel); 133 if (err) { 134 /* if we loaded above successfully, attach has to succeed */ 135 p_err("failed to attach PID iterator: %d", err); 136 goto out; 137 } 138 139 fd = bpf_iter_create(bpf_link__fd(skel->links.iter)); 140 if (fd < 0) { 141 err = -errno; 142 p_err("failed to create PID iterator session: %d", err); 143 goto out; 144 } 145 146 while (true) { 147 ret = read(fd, buf, sizeof(buf)); 148 if (ret < 0) { 149 if (errno == EAGAIN) 150 continue; 151 err = -errno; 152 p_err("failed to read PID iterator output: %d", err); 153 goto out; 154 } 155 if (ret == 0) 156 break; 157 if (ret % sizeof(*e)) { 158 err = -EINVAL; 159 p_err("invalid PID iterator output format"); 160 goto out; 161 } 162 ret /= sizeof(*e); 163 164 e = (void *)buf; 165 for (i = 0; i < ret; i++, e++) { 166 add_ref(*map, e); 167 } 168 } 169 err = 0; 170 out: 171 if (fd >= 0) 172 close(fd); 173 pid_iter_bpf__destroy(skel); 174 return err; 175 } 176 177 void delete_obj_refs_table(struct hashmap *map) 178 { 179 struct hashmap_entry *entry; 180 size_t bkt; 181 182 if (!map) 183 return; 184 185 hashmap__for_each_entry(map, entry, bkt) { 186 struct obj_refs *refs = entry->value; 187 188 free(refs->refs); 189 free(refs); 190 } 191 192 hashmap__free(map); 193 } 194 195 void emit_obj_refs_json(struct hashmap *map, __u32 id, 196 json_writer_t *json_writer) 197 { 198 struct hashmap_entry *entry; 199 200 if (hashmap__empty(map)) 201 return; 202 203 hashmap__for_each_key_entry(map, entry, u32_as_hash_field(id)) { 204 struct obj_refs *refs = entry->value; 205 int i; 206 207 if (refs->ref_cnt == 0) 208 break; 209 210 if (refs->has_bpf_cookie) 211 jsonw_lluint_field(json_writer, "bpf_cookie", refs->bpf_cookie); 212 213 jsonw_name(json_writer, "pids"); 214 jsonw_start_array(json_writer); 215 for (i = 0; i < refs->ref_cnt; i++) { 216 struct obj_ref *ref = &refs->refs[i]; 217 218 jsonw_start_object(json_writer); 219 jsonw_int_field(json_writer, "pid", ref->pid); 220 jsonw_string_field(json_writer, "comm", ref->comm); 221 jsonw_end_object(json_writer); 222 } 223 jsonw_end_array(json_writer); 224 break; 225 } 226 } 227 228 void emit_obj_refs_plain(struct hashmap *map, __u32 id, const char *prefix) 229 { 230 struct hashmap_entry *entry; 231 232 if (hashmap__empty(map)) 233 return; 234 235 hashmap__for_each_key_entry(map, entry, u32_as_hash_field(id)) { 236 struct obj_refs *refs = entry->value; 237 int i; 238 239 if (refs->ref_cnt == 0) 240 break; 241 242 if (refs->has_bpf_cookie) 243 printf("\n\tbpf_cookie %llu", (unsigned long long) refs->bpf_cookie); 244 245 printf("%s", prefix); 246 for (i = 0; i < refs->ref_cnt; i++) { 247 struct obj_ref *ref = &refs->refs[i]; 248 249 printf("%s%s(%d)", i == 0 ? "" : ", ", ref->comm, ref->pid); 250 } 251 break; 252 } 253 } 254 255 256 #endif 257