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/*
* Remote-control functions.
*
* Copyright 2012 Andrew Wood, distributed under the Artistic License 2.0.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "options.h"
#include "pv.h"
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
struct remote_msg {
long mtype;
unsigned char progress; /* progress bar flag */
unsigned char timer; /* timer flag */
unsigned char eta; /* ETA flag */
unsigned char rate; /* rate counter flag */
unsigned char average_rate; /* average rate counter flag */
unsigned char bytes; /* bytes transferred flag */
unsigned long long rate_limit; /* rate limit, in bytes per second */
unsigned long long buffer_size; /* buffer size, in bytes (0=default) */
unsigned long long size; /* total size of data */
double interval; /* interval between updates */
unsigned int width; /* screen width */
unsigned int height; /* screen height */
char name[256]; /* RATS: ignore */
};
static opts_t remote__opts = NULL;
/*
* Return a key for use with msgget() which will be unique to the current
* user.
*
* We can't just use ftok() because the queue needs to be user-specific
* so that a user cannot send messages to another user's process, and we
* can't easily find out the terminal a given process is connected to in a
* cross-platform way.
*/
static key_t remote__genkey(opts_t opts)
{
int uid;
key_t key;
uid = geteuid();
if (uid < 0)
uid = 0;
key = ftok("/tmp", 'P') | uid;
return key;
}
/*
* Return a message queue ID that is unique to the current user and the
* given process ID, or -1 on error.
*/
static int remote__msgget(opts_t opts)
{
return msgget(remote__genkey(opts), IPC_CREAT | 0600);
}
/*
* Set the options of a remote process by setting up an IPC message queue,
* sending a message containing the new options, and then sending a SIGUSR1
* so the process knows it has a message to read.
*
* Returns nonzero on error.
*/
int remote_set(opts_t opts)
{
struct remote_msg msgbuf;
int msgid;
memset(&msgbuf, 0, sizeof(msgbuf));
msgbuf.mtype = opts->remote;
msgbuf.progress = opts->progress;
msgbuf.timer = opts->timer;
msgbuf.eta = opts->eta;
msgbuf.rate = opts->rate;
msgbuf.average_rate = opts->average_rate;
msgbuf.rate_limit = opts->rate_limit;
msgbuf.buffer_size = opts->buffer_size;
msgbuf.size = opts->size;
msgbuf.interval = opts->interval;
msgbuf.width = opts->width;
msgbuf.height = opts->height;
if (opts->name != NULL) {
strncpy(msgbuf.name, opts->name, sizeof(msgbuf.name) - 1);
}
msgid = remote__msgget(opts);
if (msgid < 0) {
fprintf(stderr, "%s: %s\n", opts->program_name,
strerror(errno));
return 1;
}
if (msgsnd(msgid, &msgbuf, sizeof(msgbuf) - sizeof(long), 0) != 0) {
fprintf(stderr, "%s: %s\n", opts->program_name,
strerror(errno));
return 1;
}
if (kill(opts->remote, SIGUSR1) != 0) {
fprintf(stderr, "%s: %s\n", opts->program_name,
strerror(errno));
return 1;
}
return 0;
}
/*
* Handle SIGUSR1 by replacing the current process's options with those
* being passed in via IPC message. The message queue is deleted afterwards.
*/
static void remote__sig_usr1(int s)
{
struct remote_msg msgbuf;
struct msqid_ds qbuf;
ssize_t got;
int msgid;
memset(&msgbuf, 0, sizeof(msgbuf));
msgid = remote__msgget(remote__opts);
if (msgid < 0) {
return;
}
got =
msgrcv(msgid, &msgbuf, sizeof(msgbuf) - sizeof(long), getpid(),
IPC_NOWAIT);
if (got < 0) {
msgctl(msgid, IPC_RMID, &qbuf);
return;
}
if (msgctl(msgid, IPC_RMID, &qbuf) == 0) {
if (qbuf.msg_qnum < 1) {
msgctl(msgid, IPC_RMID, &qbuf);
}
}
if ((got < 1) || (remote__opts == NULL)) {
return;
}
remote__opts->progress = msgbuf.progress;
remote__opts->timer = msgbuf.timer;
remote__opts->eta = msgbuf.eta;
remote__opts->rate = msgbuf.rate;
remote__opts->average_rate = msgbuf.average_rate;
if (msgbuf.rate_limit > 0)
remote__opts->rate_limit = msgbuf.rate_limit;
if (msgbuf.buffer_size > 0) {
remote__opts->buffer_size = msgbuf.buffer_size;
pv_set_buffer_size(msgbuf.buffer_size, 1);
}
if (msgbuf.size > 0)
remote__opts->size = msgbuf.size;
if (msgbuf.interval > 0)
remote__opts->interval = msgbuf.interval;
if (msgbuf.width > 0)
remote__opts->width = msgbuf.width;
if (msgbuf.height > 0)
remote__opts->height = msgbuf.height;
if (msgbuf.name[0] != 0)
remote__opts->name = strdup(msgbuf.name);
}
/*
* Initialise handling of SIGUSR1 so that remote control messages can be
* processed correctly.
*/
void remote_sig_init(opts_t opts)
{
struct sigaction sa;
remote__opts = opts;
sa.sa_handler = remote__sig_usr1;
sigemptyset(&(sa.sa_mask));
sa.sa_flags = 0;
sigaction(SIGUSR1, &sa, NULL);
}
/* EOF */
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