ust: continue moving communication stuff to libustcomm and cleanup

[ust.git] / libustcomm / ustcomm.c

#define _GNU_SOURCE
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "ustcomm.h"
#include "localerr.h"

#define UNIX_PATH_MAX 108
#define SOCK_DIR "/tmp/socks"
#define UST_SIGNAL SIGIO

#define MSG_MAX 1000

static void signal_process(pid_t pid)
{
	int result;

	result = kill(pid, UST_SIGNAL);
	if(result == -1) {
		perror("kill");
		return;
	}

	sleep(1);
}

/* pid: the pid of the trace process that must receive the msg
   msg: pointer to a null-terminated message to send
   reply: location where to put the null-terminated string of the reply;
	  it must be free'd after usage
 */

int send_message(pid_t pid, const char *msg, char **reply)
{
	int fd;
	int result;
	struct sockaddr_un addr;

	result = fd = socket(PF_UNIX, SOCK_DGRAM, 0);
	if(result == -1) {
		perror("socket");
		return -1;
	}

	addr.sun_family = AF_UNIX;

	result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
	if(result >= UNIX_PATH_MAX) {
		fprintf(stderr, "string overflow allocating socket name");
		return -1;
	}

	signal_process(pid);

	result = sendto(fd, msg, strlen(msg), 0, (struct sockaddr *)&addr, sizeof(addr));
	if(result == -1) {
		perror("sendto");
		return -1;
	}

	if(!reply)
		return 0;

	*reply = (char *) malloc(MSG_MAX+1);
	result = recvfrom(fd, *reply, MSG_MAX, 0, NULL, NULL);
	if(result == -1) {
		perror("recvfrom");
		return -1;
	}
	
	(*reply)[result] = '\0';

	return 0;
}

int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg)
{
	int fd;
	int result;
	struct sockaddr_un addr;

	*msg = (char *) malloc(MSG_MAX+1);
	result = recvfrom(app->fd, *msg, MSG_MAX, 0, NULL, NULL);
	if(result == -1) {
		PERROR("recvfrom");
		return -1;
	}
	
	DBG("ustcomm_app_recv_message: result is %d, message[1] is %hhd", result, (*msg)[1]);
	(*msg)[result] = '\0';

	return 0;
}

static int init_named_socket(char *name, char **path_out)
{
	int result;
	int fd;

	struct sockaddr_un addr;
	
	result = fd = socket(PF_UNIX, SOCK_DGRAM, 0);
	if(result == -1) {
		PERROR("socket");
		return -1;
	}

	addr.sun_family = AF_UNIX;

	strncpy(addr.sun_path, name, UNIX_PATH_MAX);
	addr.sun_path[UNIX_PATH_MAX-1] = '\0';

	result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
	if(result == -1) {
		PERROR("bind");
		goto close_sock;
	}

	if(path_out)
		*path_out = strdupa(addr.sun_path);

	return fd;

	close_sock:
	close(fd);

	return -1;
}

int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
{
	int result;
	char *name;

	result = asprintf(&name, "%s/%d", SOCK_DIR, (int)pid);
	if(result >= UNIX_PATH_MAX) {
		ERR("string overflow allocating socket name");
		return -1;
	}

	handle->fd = init_named_socket(name, &handle->socketpath);
	if(handle->fd < 0) {
		goto free_name;
	}
	free(name);

	return 0;

free_name:
	free(name);
	return -1;
}

int ustcomm_init_ustd(struct ustcomm_ustd *handle)
{
	handle->fd = init_named_socket("ustd", &handle->socketpath);
	if(handle->fd < 0)
		return handle->fd;

	return 0;
}