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