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#define _GNU_SOURCE
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <alloca.h>
#include <errno.h>
#include <termios.h>
#include <sys/utsname.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#include "lib.h"
#include "opts_defs.h"
/* most of the functions here (like str_copy, fmt_ulong)
have manual pages in libowfat; http://www.fefe.de/
see also opts_defs.h for o[Oxxx]; man ngetty */
/* see out_put.c; man buffer */
#define outs(X) out_puts(X)
#define GO_out "go out!"
static struct utsname uts;
static struct stat st;
static char *tty, *o_opt, o_endchar;
char **Oo = o; /* see opts_defs.h */
static void tty_flush() { ioctl(0, TCFLSH, TCIFLUSH); }
/* Format of o[Oprint]: ab:cq:09:AZ:...; man ngetty
return -1 if 'ch' does not belongs to the set o[Oprint]; 0 success */
static int char_allow(unsigned char ch) {
unsigned char c0, c1, *x = (unsigned char *)o[Oprint];
again:
c0 = x[0]; if (!c0) return -1;
c1 = x[1]; if (!c1) return -1;
if (c0 <= ch && ch <= c1) return 0;
if (x[2] == ':') { x += 3; goto again; }
return -1;
}
/* print maximal 'len' chars from 's'; see strncpy, snprintf, printf */
static void out_max(char *s, unsigned int len) {
char c = 0;
if (s == uts.nodename && !o[Olonghostname]) c = '.';
while (len && *s && *s != c) {
out_char(*s); ++s; --len;
}
}
#define Out_MAX(X) x=X; len=sizeof(X); goto system
/* print string with escapes; man ngetty; man issue */
static void output_special_char(char *s, int len) {
char *last = s + len;
while (s < last) {
char *x, c;
if (*s != '\\') { out_char(*s); ++s; continue; }
if (++s == last) return;
c = *s++;
switch (c) {
case 's': Out_MAX(uts.sysname);
case 'n': Out_MAX(uts.nodename);
case 'r': Out_MAX(uts.release);
case 'v': Out_MAX(uts.version);
case 'm': Out_MAX(uts.machine);
case 'o': Out_MAX(uts.domainname);
system:
out_max(x,len); break;
case 'l':
outs(tty); break;
#ifndef DONT_NEED_ESC_TIME
case 't':
x = "H:M:S"; goto do_time;
case 'd':
x = (o[Odatestring]) ? "a b d Y" : "Y-m-d";
do_time:
fmt_time(x); break;
#endif
#ifndef DONT_NEED_ESC_USERS
case 'u':
case 'U':
{
char ubuf[8 + 3*sizeof(unsigned long)], *x = ubuf;
unsigned long usrs = utmp_users();
x += fmt_ulong(x, usrs);
if (c=='U') {
x += str_copynz(x, " users", 10);
if (usrs==1) --x;
}
*x = 0;
outs(ubuf);
}
break;
#endif
default:
if (s+1 < last) {
unsigned char uch = (unsigned char)c-'0';
if (uch < 4) { /* XXX \0xy is not tested */
c = (uch<<6) | ((s[0]-'0')<<3) | (s[1]-'0');
s += 2;
}
}
out_char(c);
}
}
}
/* print string 's' with escapes; man ngetty */
static void Out_sp_ch(char *s) { output_special_char(s, str_len(s)); }
/* exception: print string 's' and exit with status 'i' */
void error(char *s,int i) {
struct timespec ts = { 2, 500111222 };
Out_sp_ch("\nngetty-helper: \\d \\t \\l: ");
outs(s); out_char('\n'); out_flush();
nanosleep(&ts, 0);
tty_flush();
_exit(i);
}
/* print /etc/issue and login prompt; man issue */
static void do_prompt() {
int fd,len;
char *s;
Out_sp_ch(o[Onewline]);
s = o[Oissuefile];
if (s[0] && (fd=open(s, O_RDONLY)) >= 0) {
if (GLOBAL_fstat_READ(fd,st,s, len,64000, 1)) _exit(1);
close(fd);
output_special_char(s, len);
}
Out_sp_ch(o[Ologinprompt]);
out_flush();
}
/* get login name in logname. max length = last-logname
man ngetty; options: login-buffer, timeout */
static void get_logname(char *logname, char *last) {
char *c;
alarm(x_atoi(o[Otimeout]));
for (;;) {
for (c=logname;; c++) {
if (c == last)
error("login name too long",11);
if (read(0,c,1)<1) {
if (errno==EINTR || errno==EIO || errno==ENOENT)
_exit(0);
error("received strange error",9);
}
if (*c == '\n' || *c == '\r') {
*c=0;
break;
}
if (char_allow((unsigned char)*c))
error("bad character in login name",10);
} /* end read */
if (*logname == '-')
error("username may not start with a dash",13);
if (*logname) break;
do_prompt();
}
alarm(0);
}
/* parse string; store it in o[XXX]; see opts_defs.h; /etc/ngetty/Conf */
static char *opt_get(char *s, int len) {
if (*o_opt == *s) {
char *x = o_opt;
if (!str_diffn(x,s,len) && x[len] == o_endchar) {
if (o[Odebug] && s != tty) {
outs(x - 1);
out_char('\n');
}
return x+len+1;
}
}
return 0;
}
/* return 1 if user is in s, otherwise 0;
Format of s: ,ab,uvw,MlqR, ... ,last */
static char in_list(char *s, const char *user) {
char ch;
int len;
if (s==0 || *s==0 || user==0) return 0;
len = str_len(user);
ch = *s++;
again:
if (!str_diffn(s,user,len))
if (s[len]==ch || s[len]==0) return 1;
while (*s && *s != ch) s++;
if (*s++) goto again;
return 0;
}
/* set controlling tty */
static void set_ctty() {
if (setsid() == -1 || ioctl(0, TIOCSCTTY, (void *)1))
error(GO_out, 111);
}
int main(int argc,char *argv[]) {
int fd,len;
char *s;
struct termios term;
if (argc < 2) _exit(100);
o[Oautologinfirst] = o[Onoclearfirst] = o[Oautologinname] = "";
o[Oissuefile] = "/etc/issue";
o[Ologinprog] = LOGIN;
o[Oprint] = "az:AZ:09:,.:__";
o[Otimeout] = "180";
o[Ologinprompt] = "\\n login: ";
o[Onewline] = "\n";
o[Oclear] = "\033c";
#ifndef DONT_NEED_ESC_TIME
o[Omonths] = "JanFebMarAprMayJunJulAugSepOctNovDec";
o[Odays] = "SunMonTueWedThuFriSat";
o[Otz] = "/etc/localtime";
#endif
tty = argv[1];
uname(&uts);
if (dup(0) !=1 || dup(0) !=2 || ioctl(0,TCGETS,&term)) error(GO_out, 100);
if (!str_diffn(tty, "/dev/", 5)) tty += 5;
if ((fd = open(NGETTY_HOME "/Conf", O_RDONLY)) >=0) {
char **aa=0, *q;
int tty_len = str_len(tty);
/* 40 bytes for Months or Days */
if (GLOBAL_fstat_READ(fd,st,s, len,64000, 40)) _exit(1);
close(fd);
if (st.st_uid || st.st_gid || (st.st_mode & 07022)) len = 0;
s[len]=0;
GLOBAL_split(aa,s,'\n', len);
for (; *aa; aa++) {
s=aa[0];
if (*s==0 || *s=='#' || *s=='\t' || *s==' ') continue;
o_endchar = '=';
if (*s=='=') o_opt = s+1;
else {
o_opt = s;
if (!(o_opt = opt_get(tty, tty_len))) continue;
}
for (len=0, q=(char *)P_opt; len < MAX_options; len++) {
int k = P_len[len];
if (len >= MAX_equal) o_endchar = 0;
if ((s = opt_get(q, k))) { o[len] = s; break; }
q += k;
}
}
}
if ((s=o[Onice])) nice(x_atoi(s));
if ((s=o[Oenviron])) {
char **ee=0, ch=*s++;
if (ch) GLOBAL_split(ee,s,ch, len);
environ=ee;
}
if (argc>2 && argv[2][0] == 'l') { /* get logname and execve() login */
char *loginargv[]={ o[Ologinprog], "--", 0, 0, 0 };
fork_and_exec(o[OshB]);
s = o[Oautologinfirst];
if (*s && !check_first(s,&st)) o[Oautologinname] = "";
s = o[Oautologinname];
if (*s) {
loginargv[1] = "-f";
loginargv[2] = s;
} else {
o[Oissuefile] = "";
if (!o[Onousername]) {
char *last, *buf = o[Ologinbuffer];
if (buf) last = buf + str_len(buf);
else { buf = alloca(41); last = buf + 40; }
loginargv[2] = buf;
get_logname(buf, last);
}
}
if (o[Oechooff]) {
term.c_lflag &= ~(ECHO|ISIG);
ioctl(0, TCSETS, &term);
}
if ((s=o[Ologinargv])) {
loginargv[1] = s; /* change '--' or '-f' with login-argv */
loginargv[3] = tty;
}
s = loginargv[2];
if (in_list(o[Odeny],s) ||
(o[Oallow] && in_list(o[Oallow],s)==0))
error("login is disabled",14);
out_flush();
tty_flush();
utmp_do(1,tty);
if ((s=o[Ochroot])) chroot(s);
if ((s=o[Ochdir])) chdir(s);
set_ctty();
execve(*loginargv, loginargv, environ);
} else { /* print /etc/issue and exit */
char *clear = o[Oclear];
tty_flush();
fork_and_exec(o[OshA]);
if ((s=o[Odelay])) {
struct timespec ts = { x_atoi(s), 100200300 };
nanosleep(&ts, 0);
}
s = o[Onoclearfirst];
if (*s && check_first(s,&st)) clear = "";
Out_sp_ch(clear);
utmp_do(0,tty);
do_prompt();
#ifdef HAVE_SYSTEM_VHANGUP
if (!o[Onohangup]) { set_ctty(); vhangup(); }
#endif
}
_exit(0);
}
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