talk.c - unbuffered write.c - (nf)
utzoo!decvax!pur-ee!ks
utzoo!decvax!pur-ee!ks
Sun Aug 1 01:26:30 AEST 1982
#R:pur-ee:9200001:pur-ee:9200002:000:6339
pur-ee!ks Jul 31 23:34:00 1982
"Better" version of talk.c with a few problems fixed..
Thanks to sdcarl!rusty and psi!jed.
Kirk Smith
Purdue EE
static char *sccsid = "@(#)talk.c 4.2 (pur-ee!aef & Berkeley) 10/1/80";
/*
* TALK
* write to another user
* (from write.c)
* Modified A E Feather for unbuffered writes
* 29-Oct-80
* Modified to handle "newtty" driver ctlecho mode
* pur-ee!aef 1-17-81
* Modified to set terminal to -echo mode to make the screen reflect erasures
* like on the other terminal. Also eliminated need for local mode stuff.
* Handles STOP signals from terminals properly for BSD systems.
* pur-ee!ks 7-31-8 (with help from sdcarl!rusty)
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <utmp.h>
#include <time.h>
#include <sgtty.h>
struct sgttyb tbuf;
short cptr;
#define SETMODES gtty(0,&tbuf); tbuf.sg_flags |= CBREAK;\
tbuf.sg_flags &= ~ECHO; stty(0,&tbuf)
#define RESETMODES gtty(0,&tbuf); tbuf.sg_flags &= ~CBREAK;\
tbuf.sg_flags |= ECHO; stty(0,&tbuf)
#define NMAX sizeof(ubuf.ut_name)
#define LMAX sizeof(ubuf.ut_line)
char *strcat();
char *strcpy();
struct utmp ubuf;
int signum[] = {SIGHUP, SIGINT, SIGQUIT, 0};
char me[10] = "???";
char *him;
char *mytty;
char histty[32];
char *histtya;
char *ttyname();
char *rindex();
int logcnt;
int eof();
int timout();
FILE *tf;
char *getenv();
main(argc, argv)
char *argv[];
{
struct stat stbuf;
register ii, i;
register FILE *uf;
int c1, c2, c3;
long clock = time( 0 );
struct tm *localtime();
struct tm *localclock = localtime( &clock );
if(argc < 2) {
printf("usage: talk user [ttyname]\n");
exit(1);
}
him = argv[1];
if(argc > 2)
histtya = argv[2];
if ((uf = fopen("/etc/utmp", "r")) == NULL) {
printf("cannot open /etc/utmp\n");
goto cont;
}
mytty = ttyname(2);
if (mytty == NULL) {
printf("Can't find your tty\n");
exit(1);
}
/* check if message permission on mytty is on */
if(stat(mytty, &stbuf) < 0){
printf("Can't stat your tty!\n");
exit(1);
}
if((stbuf.st_mode&02) == 0){
printf("Your message permission is OFF!\n");
exit(1);
}
mytty = rindex(mytty, '/') + 1;
if (histtya) {
strcpy(histty, "/dev/");
strcat(histty, histtya);
}
while (fread((char *)&ubuf, sizeof(ubuf), 1, uf) == 1) {
if (strcmp(ubuf.ut_line, mytty)==0) {
for(i=0; i<NMAX; i++) {
c1 = ubuf.ut_name[i];
if(c1 == ' ')
c1 = 0;
me[i] = c1;
if(c1 == 0)
break;
}
}
if (histtya != 0)
for(i=0; i<LMAX; i++) {
c1 = histty[i+5];
c2 = ubuf.ut_line[i];
if(c1 == 0)
if(c2 == 0 || c2 == ' '){
for(ii=0; ii<NMAX; ii++) {
c1 = him[ii];
c2 = ubuf.ut_name[ii];
if(c1 == 0)
if(c2 == 0 || c2 == ' ')
break;
if(c1 != c2) {
histty[0] = '\0';
break;
}
}
}
if(c1 != c2)
break;
}
if(him[0] != '-' || him[1] != 0)
for(i=0; i<NMAX; i++) {
c1 = him[i];
c2 = ubuf.ut_name[i];
if(c1 == 0)
if(c2 == 0 || c2 == ' ')
break;
if(c1 != c2)
goto nomat;
}
logcnt++;
if (histtya==0 && logcnt == 2) {
printf("%s logged more than once\n", him);
printf("on: %s", histty+5);
}
if (histtya==0 && logcnt > 1){
printf(", %s", ubuf.ut_line);
}
if (histtya==0) {
strcpy(histty, "/dev/");
strcat(histty, ubuf.ut_line);
}
nomat:
;
}
cont:
if (logcnt==0 && histty[0]=='\0') {
printf("%s not logged in.\n", him);
exit(1);
}
if(histtya == 0 && logcnt > 1){
printf("\nTalk to which one: ");
fflush(stdout);
strcpy(histty, "/dev/");
i = read(0, histty+5, 8);
if(i>8)i=8;
histty[i+4] = '\0';
lseek(fileno(uf), 0L, 0);
while (fread((char *)&ubuf, sizeof(ubuf), 1, uf) == 1) {
for(i=0; i<LMAX; i++) {
c1 = histty[i+5];
c2 = ubuf.ut_line[i];
if(c1 == 0)
if(c2 == 0 || c2 == ' '){
for(ii=0; ii<NMAX; ii++) {
c1 = him[ii];
c2 = ubuf.ut_name[ii];
if(c1 == 0)
if(c2 == 0 || c2 == ' ')
goto fwd;
if(c1 != c2){
histty[0] = '\0';
break;
}
}
goto fwd;
}
if(c1 != c2)
break;
}
}
}
fwd:
fclose(uf);
if(histty[0] == 0) {
printf(him);
if(logcnt)
printf(" not on that tty\n"); else
printf(" not logged in\n");
exit(1);
}
if (access(histty, 0) < 0) {
printf("No such tty\n");
exit(1);
}
signal(SIGALRM, timout);
alarm(5);
if ((tf = fopen(histty, "w")) == NULL)
goto perm;
alarm(0);
if (fstat(fileno(tf), &stbuf) < 0)
goto perm;
if ((stbuf.st_mode&02) == 0)
goto perm;
sigs(eof);
fprintf(tf, "\r\nMessage from ");
#ifdef interdata
fprintf(tf, "(Interdata) " );
#endif
fprintf(tf, "%s on %s at %d:%02d ...\r\n"
, me, mytty , localclock -> tm_hour , localclock -> tm_min );
fflush(tf);
SETMODES;
printf("\07");
fflush(stdout);
cptr = 0;
for(;;) {
char buf;
for(c3 = 0; c3 < 10 ; c3++)
{
i = read(0, &buf, 1);
if(i > 0)
break;
}
if(i <= 0)
eof();
if(buf == '\04')
eof();
if(buf == tbuf.sg_erase){
write(1, "\b \b", 3);
write( fileno( tf ), "\b \b", 3);
if(cptr>0)
cptr--;
continue;
}
write(1, &buf, 1);
cptr++;
if(buf == '!' && cptr == 1) {
char buf1[128];
RESETMODES;
while( buf != '\n') {
read(0, &buf, 1);
buf1[cptr++] = buf;
}
buf1[--cptr] = 0;
ex(buf1);
cptr = 0;
continue;
}
write(fileno(tf), &buf, 1);
if ( buf == '\n' ){
write( fileno( tf ) , "\r" , 1 );
cptr = 0;
}
}
perm:
printf("Permission denied\n");
exit(1);
}
timout()
{
printf("Timeout opening their tty\n");
exit(1);
}
eof()
{
fprintf(tf, "EOF\r\n");
RESETMODES;
exit(0);
}
ex(bp)
char *bp;
{
register i;
sigs(SIG_IGN);
i = fork();
if(i < 0) {
printf("Try again\n");
goto out;
}
if(i == 0) {
sigs(SIG_IGN);
execl(getenv("SHELL") ? getenv("SHELL") : "/bin/sh", "sh", "-c", bp+1, 0);
exit(0);
}
while(wait((int *)NULL) != i)
;
printf("!\n");
out:
SETMODES;
sigs(eof);
}
sigs(sig)
int (*sig)();
{
register i;
#ifdef SIGTSTP
int onsusp();
if(sig == SIG_DFL)
signal(SIGTSTP, SIG_DFL);
else
signal(SIGTSTP, onsusp);
#endif
for(i=0;signum[i];i++)
signal(signum[i],sig);
}
#ifdef SIGTSTP
onsusp()
{
signal(SIGTSTP, SIG_IGN);
RESETMODES;
sigs(SIG_DFL);
kill(0, SIGTSTP);
/* the pc stops here */
SETMODES;
sigs(eof);
}
#endif
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