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#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include "node.h"
/*
* This one (c) 1996 by Heikki Hannikainen, OH7LZB <hessu@pspt.fi>
*/
#define FIRST_KEY (3694 - 1) /* Where to start looking for a key */
#define LAST_KEY (FIRST_KEY + 200) /* How far to search */
#define M_LEN 1024 /* Largest message transferred */
struct nmsgbuf {
long mtype; /* message type, must be > 0 */
char mtext[M_LEN]; /* message data */
};
static int ipc_id = -1;
static void usr2_handler(int sig)
{
struct nmsgbuf buf;
if (msgrcv(ipc_id, (struct msgbuf *)&buf, M_LEN, 0, IPC_NOWAIT|MSG_NOERROR) != -1) {
node_msg("%s", buf.mtext);
} else
log(L_ERROR, "usr2_handler: Catched SIGUSR2, but couldn't receive a message");
signal(SIGUSR2, usr2_handler); /* Restore handler */
}
int ipc_send(key_t key, long mtype, char *mtext)
{
struct nmsgbuf buf;
int id;
if ((id = msgget(key, 7)) == -1) {
node_perror("ipc_send: Could not get transmit channel", errno);
return -1;
}
buf.mtype = mtype;
strncpy(buf.mtext, mtext, M_LEN);
if (msgsnd(id, (struct msgbuf *)&buf, M_LEN, 0) == -1) {
node_perror("ipc_send: Could not send message", errno);
return -1;
}
return 0;
}
int ipc_open(void)
{
key_t key = FIRST_KEY;
do {
key++;
ipc_id = msgget(key, 7 | IPC_CREAT | IPC_EXCL);
} while ((ipc_id == -1) && (key != LAST_KEY));
if (ipc_id == -1)
node_perror("ipc_open: Could not get an IPC channel", errno);
#if 0
node_msg("debug: ipc_id=%d key=%d", ipc_id, key);
#endif
User.ipc_key = key;
if (key != -1)
signal(SIGUSR2, usr2_handler);
else
signal(SIGUSR2, SIG_IGN);
return 0;
}
int ipc_close(void)
{
struct msqid_ds buf;
if (ipc_id != -1) /* Remove the IPC channel */
if (msgctl(ipc_id, IPC_RMID, &buf) == -1) {
log(L_ERROR, "ipc_close: Could not remove IPC channel: %s", strerror(errno));
return -1;
}
return 0;
}
int do_talk(int argc, char **argv)
{
FILE *f;
struct user u;
char call[10];
char mtext[M_LEN];
int i, hits = 0, sent = 0;
if (argc < 3) {
node_msg("Usage: talk <user> <message>");
return 0;
}
if ((f = fopen(DATA_NODE_LOGIN_FILE, "r")) == NULL) {
node_perror(DATA_NODE_LOGIN_FILE, errno);
return 0;
}
sprintf(mtext, "Message from %s:\n", User.call);
for (i = 2; i < argc; i++) {
strncat(mtext, argv[i], M_LEN - strlen(mtext));
strncat(mtext, " ", M_LEN - strlen(mtext));
}
strncat(mtext, "\n--", M_LEN - strlen(mtext));
strncpy(call, argv[1], 9);
call[9] = 0;
while (fread(&u, sizeof(u), 1, f) == 1) {
if (u.pid == -1 || (kill(u.pid, 0) == -1 && errno == ESRCH))
continue;
if (!strcasecmp(u.call, call)) {
hits++;
if (u.ipc_key != -1 && u.state == STATE_IDLE) {
ipc_send(u.ipc_key, 1, mtext);
kill(u.pid, SIGUSR2);
sent++;
}
}
}
fclose(f);
if (hits == 0)
node_msg("No such user %s", call);
else if (sent == 0)
node_msg("%s is busy, cannot talk to him right now.", call);
return 0;
}
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