path: root/tools/testing/selftests/bpf/trace_helpers.c

// SPDX-License-Identifier: GPL-2.0
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <pthread.h>
#include <unistd.h>
#include <linux/perf_event.h>
#include <linux/fs.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include "trace_helpers.h"
#include <linux/limits.h>
#include <libelf.h>
#include <gelf.h>
#include "bpf/hashmap.h"
#include "bpf/libbpf_internal.h"
#include "bpf_util.h"

#define TRACEFS_PIPE	"/sys/kernel/tracing/trace_pipe"
#define DEBUGFS_PIPE	"/sys/kernel/debug/tracing/trace_pipe"

struct ksyms {
	struct ksym *syms;
	size_t sym_cap;
	size_t sym_cnt;
};

static struct ksyms *ksyms;
static pthread_mutex_t ksyms_mutex = PTHREAD_MUTEX_INITIALIZER;

static int ksyms__add_symbol(struct ksyms *ksyms, const char *name,
			     unsigned long addr)
{
	void *tmp;

	tmp = strdup(name);
	if (!tmp)
		return -ENOMEM;
	ksyms->syms[ksyms->sym_cnt].addr = addr;
	ksyms->syms[ksyms->sym_cnt].name = tmp;
	ksyms->sym_cnt++;
	return 0;
}

void free_kallsyms_local(struct ksyms *ksyms)
{
	unsigned int i;

	if (!ksyms)
		return;

	if (!ksyms->syms) {
		free(ksyms);
		return;
	}

	for (i = 0; i < ksyms->sym_cnt; i++)
		free(ksyms->syms[i].name);
	free(ksyms->syms);
	free(ksyms);
}

static struct ksyms *load_kallsyms_local_common(ksym_cmp_t cmp_cb)
{
	FILE *f;
	char func[256], buf[256];
	char symbol;
	void *addr;
	int ret;
	struct ksyms *ksyms;

	f = fopen("/proc/kallsyms", "r");
	if (!f)
		return NULL;

	ksyms = calloc(1, sizeof(struct ksyms));
	if (!ksyms) {
		fclose(f);
		return NULL;
	}

	while (fgets(buf, sizeof(buf), f)) {
		if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
			break;
		if (!addr)
			continue;

		ret = libbpf_ensure_mem((void **) &ksyms->syms, &ksyms->sym_cap,
					sizeof(struct ksym), ksyms->sym_cnt + 1);
		if (ret)
			goto error;
		ret = ksyms__add_symbol(ksyms, func, (unsigned long)addr);
		if (ret)
			goto error;
	}
	fclose(f);
	qsort(ksyms->syms, ksyms->sym_cnt, sizeof(struct ksym), cmp_cb);
	return ksyms;

error:
	fclose(f);
	free_kallsyms_local(ksyms);
	return NULL;
}

static int ksym_cmp(const void *p1, const void *p2)
{
	return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
}

struct ksyms *load_kallsyms_local(void)
{
	return load_kallsyms_local_common(ksym_cmp);
}

struct ksyms *load_kallsyms_custom_local(ksym_cmp_t cmp_cb)
{
	return load_kallsyms_local_common(cmp_cb);
}

int load_kallsyms(void)
{
	pthread_mutex_lock(&ksyms_mutex);
	if (!ksyms)
		ksyms = load_kallsyms_local();
	pthread_mutex_unlock(&ksyms_mutex);
	return ksyms ? 0 : 1;
}

struct ksym *ksym_search_local(struct ksyms *ksyms, long key)
{
	int start = 0, end = ksyms->sym_cnt;
	int result;

	/* kallsyms not loaded. return NULL */
	if (ksyms->sym_cnt <= 0)
		return NULL;

	while (start < end) {
		size_t mid = start + (end - start) / 2;

		result = key - ksyms->syms[mid].addr;
		if (result < 0)
			end = mid;
		else if (result > 0)
			start = mid + 1;
		else
			return &ksyms->syms[mid];
	}

	if (start >= 1 && ksyms->syms[start - 1].addr < key &&
	    key < ksyms->syms[start].addr)
		/* valid ksym */
		return &ksyms->syms[start - 1];

	/* out of range. return _stext */
	return &ksyms->syms[0];
}

struct ksym *search_kallsyms_custom_local(struct ksyms *ksyms, const void *p,
					  ksym_search_cmp_t cmp_cb)
{
	int start = 0, mid, end = ksyms->sym_cnt;
	struct ksym *ks;
	int result;

	while (start < end) {
		mid = start + (end - start) / 2;
		ks = &ksyms->syms[mid];
		result = cmp_cb(p, ks);
		if (result < 0)
			end = mid;
		else if (result > 0)
			start = mid <