cgproxy/execsnoop-libbpf/trace_helpers.c

/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <sys/resource.h>
#include <time.h>
#include "trace_helpers.h"

#define min(x, y) ({				 \
	typeof(x) _min1 = (x);			 \
	typeof(y) _min2 = (y);			 \
	(void) (&_min1 == &_min2);		 \
	_min1 < _min2 ? _min1 : _min2; })

struct ksyms {
	struct ksym *syms;
	int syms_sz;
	int syms_cap;
	char *strs;
	int strs_sz;
	int strs_cap;
};

static int ksyms__add_symbol(struct ksyms *ksyms, const char *name, unsigned long addr)
{
	size_t new_cap, name_len = strlen(name) + 1;
	struct ksym *ksym;
	void *tmp;

	if (ksyms->strs_sz + name_len > ksyms->strs_cap) {
		new_cap = ksyms->strs_cap * 4 / 3;
		if (new_cap < ksyms->strs_sz + name_len)
			new_cap = ksyms->strs_sz + name_len;
		if (new_cap < 1024)
			new_cap = 1024;
		tmp = realloc(ksyms->strs, new_cap);
		if (!tmp)
			return -1;
		ksyms->strs = tmp;
		ksyms->strs_cap = new_cap;
	}
	if (ksyms->syms_sz + 1 > ksyms->syms_cap) {
		new_cap = ksyms->syms_cap * 4 / 3;
		if (new_cap < 1024)
			new_cap = 1024;
		tmp = realloc(ksyms->syms, sizeof(*ksyms->syms) * new_cap);
		if (!tmp)
			return -1;
		ksyms->syms = tmp;
		ksyms->syms_cap = new_cap;
	}

	ksym = &ksyms->syms[ksyms->syms_sz];
	/* while constructing, re-use pointer as just a plain offset */
	ksym->name = (void *)(unsigned long)ksyms->strs_sz;
	ksym->addr = addr;

	memcpy(ksyms->strs + ksyms->strs_sz, name, name_len);
	ksyms->strs_sz += name_len;
	ksyms->syms_sz++;

	return 0;
}

static int ksym_cmp(const void *p1, const void *p2)
{
	const struct ksym *s1 = p1, *s2 = p2;

	if (s1->addr == s2->addr)
		return strcmp(s1->name, s2->name);
	return s1->addr < s2->addr ? -1 : 1;
}

struct ksyms *ksyms__load(void)
{
	char sym_type, sym_name[256];
	struct ksyms *ksyms;
	unsigned long sym_addr;
	int i, ret;
	FILE *f;

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

	ksyms = calloc(1, sizeof(*ksyms));
	if (!ksyms)
		goto err_out;

	while (true) {
		ret = fscanf(f, "%lx %c %s%*[^\n]\n",
			     &sym_addr, &sym_type, sym_name);
		if (ret == EOF && feof(f))
			break;
		if (ret != 3)
			goto err_out;
		if (ksyms__add_symbol(ksyms, sym_name, sym_addr))
			goto err_out;
	}

	/* now when strings are finalized, adjust pointers properly */
	for (i = 0; i < ksyms->syms_sz; i++)
		ksyms->syms[i].name += (unsigned long)ksyms->strs;

	qsort(ksyms->syms, ksyms->syms_sz, sizeof(*ksyms->syms), ksym_cmp);

	fclose(f);
	return ksyms;

err_out:
	ksyms__free(ksyms);
	fclose(f);
	return NULL;
}

void ksyms__free(struct ksyms *ksyms)
{
	if (!ksyms)
		return;

	free(ksyms->syms);
	free(ksyms->strs);
	free(ksyms);
}

const struct ksym *ksyms__map_addr(const struct ksyms *ksyms,
				   unsigned long addr)
{
	int start = 0, end = ksyms->syms_sz - 1, mid;
	unsigned long sym_addr;

	/* find largest sym_addr <= addr using binary search */
	while (start < end) {
		mid = start + (end - start + 1) / 2;
		sym_addr = ksyms->syms[mid].addr;

		if (sym_addr <= addr)
			start = mid;
		else
			end = mid - 1;
	}

	if (start == end && ksyms->syms[start].addr <= addr)
		return &ksyms->syms[start];
	return NULL;
}

const struct ksym *ksyms__get_symbol(const struct ksyms *ksyms,
				     const char *name)
{
	int i;

	for (i = 0; i < ksyms->syms_sz; i++) {
		if (strcmp(ksyms->syms[i].name, name) == 0)
			return &ksyms->syms[i];
	}

	return NULL;
}

static void print_stars(unsigned int val, unsigned int val_max, int width)
{
	int num_stars, num_spaces, i;
	bool need_plus;

	num_stars = min(val, val_max) * width / val_max;
	num_spaces = width - num_stars;
	need_plus = val > val_max;

	for (i = 0; i < num_stars; i++)
		printf("*");
	for (i = 0; i < num_spaces; i++)
		printf(" ");
	if (need_plus)
		printf("+");
}

void print_log2_hist(unsigned int *vals, int vals_size, char *val_type)
{
	int stars_max = 40, idx_max = -1;
	unsigned int val, val_max = 0;
	unsigned long long low, high;
	int stars, width, i;

	for (i = 0; i < vals_size; i++) {
		val = vals[i];
		if (val > 0)
			idx_max = i;
		if (val > val_max)
			val_max = val;
	}

	if (idx_max < 0)
		return;

	printf("%*s%-*s : count    distribution\n", idx_max <= 32 ? 5 : 15, "",
		idx_max <= 32 ? 19 : 29, val_type);

	if (idx_max <= 32)
		stars = stars_max;
	else
		stars = stars_max / 2;

	for (i = 0; i <= idx_max; i++) {
		low = (1ULL << (i + 1)) >> 1;
		high = (1ULL << (i + 1)) - 1;
		if (low == high)
			low -= 1;
		val = vals[i];
		width = idx_max <= 32 ? 10 : 20;
		printf("%*lld -> %-*lld : %-8d |", width, low, width, high, val);
		print_stars(val, val_max, stars);
		printf("|\n");
	}
}

unsigned long long get_ktime_ns(void)
{
	struct timespec ts;

	clock_gettime(CLOCK_MONOTONIC, &ts);
	return ts.tv_sec * NSEC_PER_SEC + ts.tv_nsec;
}

int bump_memlock_rlimit(void)
{
	struct rlimit rlim_new = {
		.rlim_cur	= RLIM_INFINITY,
		.rlim_max	= RLIM_INFINITY,
	};

	return setrlimit(RLIMIT_MEMLOCK, &rlim_new);
}