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 82 err = hashmap__append(map, u32_as_hash_field(e->id), refs); 83 if (err) 84 p_err("failed to append entry to hashmap for ID %u: %s", 85 e->id, strerror(errno)); 86 } 87 88 static int __printf(2, 0) 89 libbpf_print_none(__maybe_unused enum libbpf_print_level level, 90 __maybe_unused const char *format, 91 __maybe_unused va_list args) 92 { 93 return 0; 94 } 95 96 int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type) 97 { 98 struct pid_iter_entry *e; 99 char buf[4096 / sizeof(*e) * sizeof(*e)]; 100 struct pid_iter_bpf *skel; 101 int err, ret, fd = -1, i; 102 libbpf_print_fn_t default_print; 103 104 *map = hashmap__new(hash_fn_for_key_as_id, equal_fn_for_key_as_id, NULL); 105 if (IS_ERR(*map)) { 106 p_err("failed to create hashmap for PID references"); 107 return -1; 108 } 109 set_max_rlimit(); 110 111 skel = pid_iter_bpf__open(); 112 if (!skel) { 113 p_err("failed to open PID iterator skeleton"); 114 return -1; 115 } 116 117 skel->rodata->obj_type = type; 118 119 /* we don't want output polluted with libbpf errors if bpf_iter is not 120 * supported 121 */ 122 default_print = libbpf_set_print(libbpf_print_none); 123 err = pid_iter_bpf__load(skel); 124 libbpf_set_print(default_print); 125 if (err) { 126 /* too bad, kernel doesn't support BPF iterators yet */ 127 err = 0; 128 goto out; 129 } 130 err = pid_iter_bpf__attach(skel); 131 if (err) { 132 /* if we loaded above successfully, attach has to succeed */ 133 p_err("failed to attach PID iterator: %d", err); 134 goto out; 135 } 136 137 fd = bpf_iter_create(bpf_link__fd(skel->links.iter)); 138 if (fd < 0) { 139 err = -errno; 140 p_err("failed to create PID iterator session: %d", err); 141 goto out; 142 } 143 144 while (true) { 145 ret = read(fd, buf, sizeof(buf)); 146 if (ret < 0) { 147 if (errno == EAGAIN) 148 continue; 149 err = -errno; 150 p_err("failed to read PID iterator output: %d", err); 151 goto out; 152 } 153 if (ret == 0) 154 break; 155 if (ret % sizeof(*e)) { 156 err = -EINVAL; 157 p_err("invalid PID iterator output format"); 158 goto out; 159 } 160 ret /= sizeof(*e); 161 162 e = (void *)buf; 163 for (i = 0; i < ret; i++, e++) { 164 add_ref(*map, e); 165 } 166 } 167 err = 0; 168 out: 169 if (fd >= 0) 170 close(fd); 171 pid_iter_bpf__destroy(skel); 172 return err; 173 } 174 175 void delete_obj_refs_table(struct hashmap *map) 176 { 177 struct hashmap_entry *entry; 178 size_t bkt; 179 180 if (!map) 181 return; 182 183 hashmap__for_each_entry(map, entry, bkt) { 184 struct obj_refs *refs = entry->value; 185 186 free(refs->refs); 187 free(refs); 188 } 189 190 hashmap__free(map); 191 } 192 193 void emit_obj_refs_json(struct hashmap *map, __u32 id, 194 json_writer_t *json_writer) 195 { 196 struct hashmap_entry *entry; 197 198 if (hashmap__empty(map)) 199 return; 200 201 hashmap__for_each_key_entry(map, entry, u32_as_hash_field(id)) { 202 struct obj_refs *refs = entry->value; 203 int i; 204 205 if (refs->ref_cnt == 0) 206 break; 207 208 jsonw_name(json_writer, "pids"); 209 jsonw_start_array(json_writer); 210 for (i = 0; i < refs->ref_cnt; i++) { 211 struct obj_ref *ref = &refs->refs[i]; 212 213 jsonw_start_object(json_writer); 214 jsonw_int_field(json_writer, "pid", ref->pid); 215 jsonw_string_field(json_writer, "comm", ref->comm); 216 jsonw_end_object(json_writer); 217 } 218 jsonw_end_array(json_writer); 219 break; 220 } 221 } 222 223 void emit_obj_refs_plain(struct hashmap *map, __u32 id, const char *prefix) 224 { 225 struct hashmap_entry *entry; 226 227 if (hashmap__empty(map)) 228 return; 229 230 hashmap__for_each_key_entry(map, entry, u32_as_hash_field(id)) { 231 struct obj_refs *refs = entry->value; 232 int i; 233 234 if (refs->ref_cnt == 0) 235 break; 236 237 printf("%s", prefix); 238 for (i = 0; i < refs->ref_cnt; i++) { 239 struct obj_ref *ref = &refs->refs[i]; 240 241 printf("%s%s(%d)", i == 0 ? "" : ", ", ref->comm, ref->pid); 242 } 243 break; 244 } 245 } 246 247 248 #endif 249