minix/commands/reboot/sh_wall.c
David van Moolenbroek 50e46307de Move MINIX reboot definitions into minix/reboot.h
Also fix a buffer overflow in commands/reboot/sh_wall.c.

Change-Id: I3a61057c4f0221d1700e14d44520b4ad17f1dbe1
2013-03-20 16:50:01 +00:00

109 lines
2.6 KiB
C

/* wall - write to all logged in users Author: V. Archer */
/*
Edvard Tuinder v892231@si.hhs.NL
Modified some things to include this with my shutdown/halt
package
*/
#define _POSIX_SOURCE 1
#include <sys/types.h>
#include <fcntl.h>
#include <pwd.h>
#include <string.h>
#include <stdio.h>
#include <time.h>
#include <utmp.h>
#include <unistd.h>
#include <sys/utsname.h>
#include <sys/stat.h>
#undef UTMP
static char UTMP[] = "/etc/utmp"; /* Currently logged in users. */
void wall( char *when, char *extra );
void crnlcat( char *message, char *more );
void
wall(when, extra)
char *when; /* When is shutdown */
char *extra; /* If non-nil, why is the shutdown */
{
struct utmp utmp;
char utmptty[5 + sizeof(utmp.ut_line) + 2];
char message[1024];
struct passwd *pw;
int utmpfd, ttyfd;
char *ourtty, *ourname;
time_t now;
struct utsname utsname;
struct stat con_st, tty_st;
if ((ourtty = ttyname(1))) {
if ((ourname = strrchr(ourtty, '/'))) ourtty = ourname+1;
} else ourtty = "system task";
if ((pw = getpwuid(getuid()))) ourname = pw->pw_name;
else ourname = "unknown";
time(&now);
if (uname(&utsname) != 0) strcpy(utsname.nodename, "?");
sprintf(message, "\r\nBroadcast message from %s@%s (%s)\r\n%.24s...\r\n",
ourname, utsname.nodename, ourtty, ctime(&now));
crnlcat(message, when);
crnlcat(message, extra);
/* Search the UTMP database for all logged-in users. */
if ((utmpfd = open(UTMP, O_RDONLY)) < 0) {
fprintf(stderr, "Cannot open utmp file\r\n");
return;
}
/* first the console */
strcpy(utmptty, "/dev/console");
if ((ttyfd = open(utmptty, O_WRONLY | O_NONBLOCK)) < 0) {
perror(utmptty);
} else {
fstat(ttyfd, &con_st);
write(ttyfd, message, strlen(message));
close(ttyfd);
}
while (read(utmpfd, (char *) &utmp, sizeof(utmp)) == sizeof(utmp)) {
/* is this the user we are looking for? */
if (utmp.ut_type != USER_PROCESS) continue;
strncpy(utmptty+5, utmp.ut_line, sizeof(utmp.ut_line));
utmptty[5 + sizeof(utmp.ut_line) + 1] = 0;
if ((ttyfd = open(utmptty, O_WRONLY | O_NONBLOCK)) < 0) {
perror(utmptty);
continue;
}
fstat(ttyfd, &tty_st);
if (tty_st.st_rdev != con_st.st_rdev)
write(ttyfd, message, strlen(message));
close(ttyfd);
}
close(utmpfd);
return;
}
void
crnlcat(message, more)
char *message, *more;
{
char *p = message;
char *m = more;
char *end = message + 1024 - 1;
while (p < end && *p != 0) p++;
while (p < end && *m != 0) {
if (*m == '\n' && (p == message || p[-1] != '\n')) {
*p++ = '\r';
if (p == end) p--;
}
*p++ = *m++;
}
*p = 0;
}