mtrace helper : Start/Stop mtrace to debug memory leak or to check memory usage by signal

mtrace_helper.c

#include <stdio.h>
#include <signal.h>
#include <mcheck.h>
#include <stdlib.h>

/*
 * mtrace Helper
 *
 * Usage : Compile with this binary
 *
 * At runtime, start with env vars
 *
 * - MALLOC_TRACE : output file from mtrace
 * - MALLOC_TRACE_SIGNUM : (Optional) Signal number to start/stop tracing
 *						   Start at launch without it
 *
 *  $ MALLOC_TRACE_SIGNUM=11 MALLOC_TRACE=`pwd`/out ./a.out
 *  or
 *  $ MALLOC_TRACE=`pwd`/out ./a.out
 *
 *
 *  NOTE: Turn off ASLR to debug symbol
 *
 *  $ echo 0 > /proc/sys/kernel/randomize_va_space
 */

static int sig_num = SIGUSR1;
static int is_installed = 0;

static void sighandler_stop(int sig)
{
	struct sigaction sa;

	sa.sa_handler = SIG_DFL;
	if (sigaction(sig_num, &sa, NULL) == -1) {
		printf(">> mtrace: Failed to add signal handler\n");
		return;
	}
	printf(">> mtrace: stop tracing\n");
	muntrace();
}

static void sighandler_start(int sig) {
	struct sigaction sa;
	printf(">> mtrace: start tracing\n");

	sa.sa_handler = sighandler_stop;
	sa.sa_flags = 0;
	sigemptyset(&sa.sa_mask);
	
	if (sigaction(sig_num, &sa, NULL) == -1) {
		printf(">> mtrace: Failed to add signal handler\n");
		return;
	}

	mtrace();
}

void __attribute__((constructor)) initialize_signal(void)
{
	struct sigaction sa;
	char *p_usr_signum;

	p_usr_signum = getenv("MALLOC_TRACE_SIGNUM");
	if (p_usr_signum != NULL) {
		sig_num = atoi(p_usr_signum);
		sa.sa_handler = sighandler_start;
		sa.sa_flags = 0;
		sigemptyset(&sa.sa_mask);
		
		if (sigaction(sig_num, &sa, NULL) == -1) {
			printf(">> mtrace: Failed to add signal handler\n");
			return;
		}
	} else {
		sighandler_start(sig_num);
	}


	printf(">> mtrace: Initialized tracing hook\n");
}

Simple version of mtrace helper.

TODO: is there anyway to avoid re-compile? like using LD_PRELOAD?