minix/commands/rlogind/rlogind.c

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2005-04-21 16:53:53 +02:00
/*
rlogind.c
Created: by Philip Homburg <philip@cs.vu.nl>
Log: Utmp improvement by Kees Bot <kjb@cs.vu.nl>
Split to compile easier on i86 by kjb
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#include <utmp.h>
#include <net/hton.h>
#define EXTERN
#include "rlogind.h"
char pty_str[]= "/dev/ptyXX";
char tty_str[]= "/dev/ttyXX";
char hex_str[16]= "0123456789abcdef";
char PATH_UTMP[] = "/etc/utmp"; /* current logins */
char PATH_WTMP[] = "/usr/adm/wtmp"; /* login/logout history */
char term[64]= "TERM=";
#define ENVSIZE (sizeof("TERM=")-1) /* skip null for concatenation. */
int confirmed= 0;
char *env[2];
char *args[10];
static void do_child(int tty_fd, char *tty_str);
static void dealloc_term(int slot, char *tty_str, int pid);
static void wtmp(char *user, char *id, char *line, int pid, int type, int slot);
static void setup_term(int fd);
static speed_t num2speed(int num);
static int do_control(char *buf, int cnt);
static void readall(char *buf, int cnt);
int main(int argc, char *argv[])
{
int error;
int i, j= 0;
int tty_fd, pty_fd;
int login_pid, write_pid;
int count, bytes, tmp_count;
char *lp= 0, *cp;
struct stat struct_stat;
int slot;
prog_name= argv[0];
/* Check if the remote user is allowed in. */
authenticate();
write(1, "", 1); /* Send the '\0' */
confirmed= 1;
/* We try to convince the other side not the do ^S/^Q, the rlogin
* protocol indicates the we only send this when XOFF is turned off
* but we don't know when this happens so we tell the other side that
* it is turned off.
*/
tcp_urg(1, 1);
write(1, "\220", 1);
tcp_urg(1, 0);
/* Let's look for a pty. */
pty_fd= -1;
for (i= 'p'; i <= 'z'; i++)
{
pty_str[sizeof(pty_str)-3]= i;
pty_str[sizeof(pty_str)-2]= '0';
error= stat(pty_str, &struct_stat);
if (error == -1)
continue;
for (j= 0; j < 16; j++)
{
pty_str[sizeof(pty_str)-2]= hex_str[j];
pty_fd= open(pty_str, O_RDWR);
if (pty_fd != -1)
break;
}
if (pty_fd != -1)
break;
}
if (pty_fd == -1)
{
printf("%s: out of ptys\r\n", prog_name);
exit(1);
}
tty_str[sizeof(pty_str)-3]= i;
tty_str[sizeof(pty_str)-2]= hex_str[j];
tty_fd= open(tty_str, O_RDWR);
if (tty_fd == -1)
{
printf("%s: unable to open '%s': %s\r\n", prog_name, tty_str,
strerror(errno));
exit(1);
}
slot= fttyslot(tty_fd);
login_pid= fork();
if (login_pid == -1)
{
printf("%s: unable to fork: %s\r\n", prog_name,
strerror(errno));
exit(1);
}
if (login_pid == 0)
{
close(pty_fd);
wtmp("", "", tty_str, login_pid, LOGIN_PROCESS, slot);
do_child(tty_fd, tty_str);
}
close(tty_fd);
write_pid= fork();
if (write_pid == -1)
{
printf("%s: unable to fork: %s\r\n", prog_name,
strerror(errno));
exit(1);
}
if (write_pid == 0)
{
dup2(pty_fd, 0);
count= 0;
for (;;)
{
if (!count)
{
count= read(0, line, sizeof(line));
if (count <= 0)
break;
lp= line;
}
bytes= write(1, lp, count);
if (bytes <= 0 || bytes > count)
break;
lp += bytes;
count -= bytes;
}
kill(getppid(), SIGKILL);
dealloc_term(slot, tty_str, login_pid);
_exit(1);
}
dup2(pty_fd, 1);
count= 0;
for (;;)
{
if (!count)
{
count= read(0, line, sizeof(line));
if (count <= 0)
break;
lp= line;
}
tmp_count= count;
cp= memchr(lp, 255, count);
if (cp)
{
tmp_count= cp-lp;
if (tmp_count == 0)
{
tmp_count= do_control(lp, count);
if (tmp_count)
{
lp += tmp_count;
count -= tmp_count;
continue;
}
}
}
bytes= write(1, lp, tmp_count);
if (bytes <= 0 || bytes > count)
break;
lp += bytes;
count -= bytes;
}
kill(write_pid, SIGKILL);
dealloc_term(slot, tty_str, login_pid);
return(0);
}
static void do_child(int tty_fd, char *tty_str)
{
int ctty_fd, tst_fd;
FILE *tty_file;
int sav_errno;
char **argp;
/* Set up the terminal attributes. */
setup_term(tty_fd);
/* Let's start the new session. */
setsid();
ctty_fd= open(tty_str, O_RDWR);
if (ctty_fd == -1)
{
printf("%s(do_child): unable to open '%s': %s\r\n",
prog_name, tty_str, strerror(errno));
exit(1);
}
/* Test if we really got a controlling tty. */
tst_fd= open("/dev/tty", O_RDWR);
if (tst_fd == -1)
{
printf(
"%s(do_child): '%s' didn't result in a controlling tty (%s)\r\n",
prog_name, tty_str, strerror(errno));
exit(1);
}
argp= args;
*argp++= "login";
*argp++= "-p";
*argp++= "-h";
*argp++= hostname;
if (authenticated)
*argp++= "-f";
if (lusername[0] != '\0')
*argp++= lusername;
/* We reached the point of no return. */
close(tst_fd);
close(tty_fd);
if (ctty_fd != 0)
{
dup2(ctty_fd, 0);
close(ctty_fd);
ctty_fd= 0;
}
dup2(ctty_fd, 1);
#if DEBUG
fprintf(stderr, "execing login\r\n");
#endif
dup2(ctty_fd, 2);
execve("/bin/login", args, env);
if (errno == ENOENT) execve("/usr/bin/login", args, env);
sav_errno= errno;
tty_file= fdopen(2, "w");
if (tty_file)
{
fprintf(tty_file, "%s(do_child): unable to exec login: %s\r\n",
prog_name, strerror(sav_errno));
fflush(tty_file);
}
_exit(1);
}
static void dealloc_term(int slot, char *tty_str, int pid)
{
wtmp("", "", tty_str, pid, DEAD_PROCESS, slot);
/* Finally we reset the owner and mode of the terminal. */
chown(tty_str, 0, 0);
chmod(tty_str, 0666);
}
static void wtmp(
char *user, /* name of user */
char *id, /* inittab ID */
char *line, /* TTY name */
int pid, /* PID of process */
int type, /* TYPE of entry */
int slot) /* slot number in UTMP */
{
/* Log an event into the UTMP and WTMP files. */
struct utmp utmp; /* UTMP/WTMP User Accounting */
int fd= -1;
int log = 1; /* log in wtmp */
char *p;
/* Strip the /dev part of the TTY name. */
p = strrchr(line, '/');
if (p != 0)
line= p+1;
if (type == DEAD_PROCESS) {
/* Don't add a logout entry for just a dying login. */
if ((fd = open(PATH_UTMP, O_RDONLY)) < 0) return;
if (lseek(fd, (off_t) slot * sizeof(utmp), SEEK_SET) != -1
&& read(fd, (void *) &utmp, sizeof(utmp)) == sizeof(utmp))
{
if (utmp.ut_type != INIT_PROCESS
&& utmp.ut_type != USER_PROCESS)
log= 0;
}
close(fd);
}
if (type == LOGIN_PROCESS) log= 0; /* and don't log this one */
/* Clear the utmp record. */
memset((void *) &utmp, 0, sizeof(utmp));
/* Enter new values. */
strncpy(utmp.ut_name, user, sizeof(utmp.ut_name));
strncpy(utmp.ut_id, id, sizeof(utmp.ut_id));
strncpy(utmp.ut_line, line, sizeof(utmp.ut_line));
strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
utmp.ut_pid = pid;
utmp.ut_type = type;
utmp.ut_time = time((time_t *)0);
if (log) {
if ((fd = open(PATH_WTMP, O_WRONLY | O_APPEND)) < 0) return;
write(fd, (char *) &utmp, sizeof(struct utmp));
close(fd);
}
/* write entry to utmp */
if ((fd = open(PATH_UTMP, O_WRONLY)) < 0) return;
if (lseek(fd, (off_t) slot * sizeof(utmp), SEEK_SET) != -1)
write(fd, (char *) &utmp, sizeof(struct utmp));
close(fd);
}
void fatal(int fd, char *msg, int err)
{
int len;
char buf[80], *bp;
bp= buf;
if (!confirmed)
*bp++= '\1';
if (err)
len= sprintf(bp, "rlogind: %s: %s.\r\n", msg, strerror(err));
else
len= sprintf(bp, "rlogind: %s.\r\n", msg);
write(fd, buf, bp+len-buf);
exit(1);
}
static void setup_term(int fd)
{
char *cp, *speed;
struct termios tt;
speed_t spd;
int num;
char *check;
cp= strchr(term, '/');
if (cp)
{
tcgetattr(fd, &tt);
*cp++= '\0';
speed= cp;
cp= strchr(speed, '/');
if (cp)
*cp++= '\0';
num= strtol(speed, &check, 0);
spd= num2speed(num);
if (spd != B0 && check[0] == '\0')
{
cfsetospeed(&tt, spd);
cfsetispeed(&tt, spd);
}
tcsetattr(fd, TCSANOW, &tt);
}
env[0]= term;
env[1]= 0;
}
static speed_t num2speed(int num)
{
static struct
{
int num;
speed_t value;
} speed_table[]=
{
{ 0, B0, }, { 50, B50, }, { 75, B75, }, { 110, B110, },
{ 134, B134, }, { 150, B150, }, { 200, B200, }, { 300, B300, },
{ 600, B600, }, { 1200, B1200, }, { 1800, B1800, },
{ 2400, B2400, }, { 4800, B4800, }, { 9600, B9600, },
{ 19200, B19200, }, { 38400, B38400, },
{ -1, -1 },
};
int i;
for (i= 0; speed_table[i].num != -1; i++)
{
if (speed_table[i].num == num)
return (speed_table[i].value);
}
return B0;
}
static int do_control(char *cp, int cnt)
{
char buf[20];
struct winsize winsize;
if (cnt > sizeof(buf))
cnt= sizeof(buf);
memcpy(buf, cp, cnt);
/* Let's fetch the first 2 bytes. */
if (cnt < 2)
readall(buf+cnt, 2-cnt);
if ((unsigned char)buf[1] != 255)
return 0;
/* Let's fetch the first 4 bytes. */
if (cnt < 4)
readall(buf+cnt, 4-cnt);
if (buf[2] != 's' || buf[3] != 's')
return 0;
/* Let's fetch a winsize structure. */
if (cnt < 4 + sizeof(winsize))
readall(buf+cnt, 4 + sizeof(winsize) - cnt);
memcpy(&winsize, buf+4, sizeof(winsize));
winsize.ws_row= ntohs(winsize.ws_row);
winsize.ws_col= ntohs(winsize.ws_col);
winsize.ws_xpixel= ntohs(winsize.ws_xpixel);
winsize.ws_ypixel= ntohs(winsize.ws_ypixel);
#if DEBUG
fprintf(stderr, "setting window size to %d, %d\r\n", winsize.ws_row,
winsize.ws_col);
#endif
ioctl(1, TIOCSWINSZ, &winsize);
return 4 + sizeof(winsize);
}
static void readall(char *buf, int cnt)
{
int res;
while(cnt)
{
res= read(0, buf, cnt);
if (res <= 0)
return;
buf += cnt;
cnt -= res;
}
}