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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2020 Facebook */
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <bpf/bpf.h>
#include "main.h"
#include "skeleton/pid_iter.h"
#ifdef BPFTOOL_WITHOUT_SKELETONS
int build_obj_refs_table(struct obj_refs_table *table, enum bpf_obj_type type)
{
return -ENOTSUP;
}
void delete_obj_refs_table(struct obj_refs_table *table) {}
void emit_obj_refs_plain(struct obj_refs_table *table, __u32 id, const char *prefix) {}
void emit_obj_refs_json(struct obj_refs_table *table, __u32 id, json_writer_t *json_writer) {}
#else /* BPFTOOL_WITHOUT_SKELETONS */
#include "pid_iter.skel.h"
static void add_ref(struct obj_refs_table *table, struct pid_iter_entry *e)
{
struct obj_refs *refs;
struct obj_ref *ref;
void *tmp;
int i;
hash_for_each_possible(table->table, refs, node, e->id) {
if (refs->id != e->id)
continue;
for (i = 0; i < refs->ref_cnt; i++) {
if (refs->refs[i].pid == e->pid)
return;
}
tmp = realloc(refs->refs, (refs->ref_cnt + 1) * sizeof(*ref));
if (!tmp) {
p_err("failed to re-alloc memory for ID %u, PID %d, COMM %s...",
e->id, e->pid, e->comm);
return;
}
refs->refs = tmp;
ref = &refs->refs[refs->ref_cnt];
ref->pid = e->pid;
memcpy(ref->comm, e->comm, sizeof(ref->comm));
refs->ref_cnt++;
return;
}
/* new ref */
refs = calloc(1, sizeof(*refs));
if (!refs) {
p_err("failed to alloc memory for ID %u, PID %d, COMM %s...",
e->id, e->pid, e->comm);
return;
}
refs->id = e->id;
refs->refs = malloc(sizeof(*refs->refs));
if (!refs->refs) {
free(refs);
p_err("failed to alloc memory for ID %u, PID %d, COMM %s...",
e->id, e->pid, e->comm);
return;
}
ref = &refs->refs[0];
ref->pid = e->pid;
memcpy(ref->comm, e->comm, sizeof(ref->comm));
refs->ref_cnt = 1;
hash_add(table->table, &refs->node, e->id);
}
static int __printf(2, 0)
libbpf_print_none(__maybe_unused enum libbpf_print_level level,
__maybe_unused const char *format,
__maybe_unused va_list args)
{
return 0;
}
int build_obj_refs_table(struct obj_refs_table *table, enum bpf_obj_type type)
{
char buf[4096];
struct pid_iter_bpf *skel;
struct pid_iter_entry *e;
int err, ret, fd = -1, i;
libbpf_print_fn_t default_print;
hash_init(table->table);
set_max_rlimit();
skel = pid_iter_bpf__open();
if (!skel) {
p_err("failed to open PID iterator skeleton");
return -1;
}
skel->rodata->obj_type = type;
/* we don't want output polluted with libbpf errors if bpf_iter is not
* supported
*/
default_print = libbpf_set_print(libbpf_print_none);
err = pid_iter_bpf__load(skel);
libbpf_set_print(default_print);
if (err) {
/* too bad, kernel doesn't support BPF iterators yet */
err = 0;
goto out;
}
err = pid_iter_bpf__attach(skel);
if (err) {
/* if we loaded above successfully, attach has to succeed */
p_err("failed to attach PID iterator: %d", err);
goto out;
}
fd = bpf_iter_create(bpf_link__fd(skel->links.iter));
if (fd < 0) {
err = -errno;
p_err("failed to create PID iterator session: %d", err);
goto out;
}
while (true) {
ret = read(fd, buf, sizeof(buf));
if (ret < 0) {
if (errno == EAGAIN)
continue;
err = -errno;
p_err("failed to read PID iterator output: %d", err);
goto out;
}
if (ret == 0)
break;
if (ret % sizeof(*e)) {
err = -EINVAL;
p_err("invalid PID iterator output format");
goto out;
}
ret /= sizeof(*e);
e = (void *)buf;
for (i = 0; i < ret; i++, e++) {
add_ref(table, e);
}
}
err = 0;
out:
if (fd >= 0)
close(fd);
pid_iter_bpf__destroy(skel);
return err;
}
void delete_obj_refs_table(struct obj_refs_table *table)
{
struct obj_refs *refs;
struct hlist_node *tmp;
unsigned int bkt;
hash_for_each_safe(table->table, bkt, tmp, refs, node) {
hash_del(&refs->node);
free(refs->refs);
free(refs);
}
}
void emit_obj_refs_json(struct obj_refs_table *table, __u32 id,
json_writer_t *json_writer)
{
struct obj_refs *refs;
struct obj_ref *ref;
int i;
if (hash_empty(table->table))
return;
hash_for_each_possible(table->table, refs, node, id) {
if (refs->id != id)
continue;
if (refs->ref_cnt == 0)
break;
jsonw_name(json_writer, "pids");
jsonw_start_array(json_writer);
for (i = 0; i < refs->ref_cnt; i++) {
ref = &refs->refs[i];
jsonw_start_object(json_writer);
jsonw_int_field(json_writer, "pid", ref->pid);
jsonw_string_field(json_writer, "comm", ref->comm);
jsonw_end_object(json_writer);
}
jsonw_end_array(json_writer);
break;
}
}
void emit_obj_refs_plain(struct obj_refs_table *table, __u32 id, const char *prefix)
{
struct obj_refs *refs;
struct obj_ref *ref;
int i;
if (hash_empty(table->table))
return;
hash_for_each_possible(table->table, refs, node, id) {
if (refs->id != id)
continue;
if (refs->ref_cnt == 0)
break;
printf("%s", prefix);
for (i = 0; i < refs->ref_cnt; i++) {
ref = &refs->refs[i];
printf("%s%s(%d)", i == 0 ? "" : ", ", ref->comm, ref->pid);
}
break;
}
}
#endif
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