/*-
* Copyright (c) 1998 Andrzej Bialecki
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* A primitive version of init(8) with simplistic user interface
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/reboot.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <ctype.h>
#include <err.h>
#ifdef USE_HISTORY
#error "Not yet. But it's quite simple to add - patches are welcome!"
#endif
#include <errno.h>
#include <fcntl.h>
#include <libutil.h>
#include <paths.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <varargs.h>
#define BUFSIZE 1024
#define MAX_CONS 12
#define NONE 0
#define SINGLE 1
#define MULTI 2
#define DEATH 3
#define FALSE 0
#define TRUE 1
char cwd[BUFSIZE];
char vty[]="0123456789abcdef";
char *progname;
char *motd=NULL;
int ncons=MAX_CONS;
int Reboot=FALSE;
int transition=MULTI;
int prevtrans=SINGLE;
jmp_buf machine;
char *trans[]={ "NONE", "SINGLE", "MULTI", "DEATH" };
extern char **environ;
/* Struct for holding session state */
struct sess {
char tty[16]; /* vty device path */
pid_t pid; /* pid of process running on it */
int (*func)(int argc, char **argv);
/* internal function to run on it (after forking) */
} ttys[MAX_CONS];
/* Struct for built-in command */
struct command {
char *cmd; /* command name */
char *descr; /* command description */
char *usage; /* usage */
char *example; /* example of usage */
int (*func)(char *); /* callback function */
};
/* Prototypes */
int cd(char *);
int pwd(char *);
int echo(char *);
int xit(char *);
int set(char *);
int unset(char *);
int env(char *);
int help(char *);
int sourcer(char *);
void do_command(int shell, char *cmdline);
void transition_handler(int);
/* Table of built-in functions */
struct command bltins[]={
{"cd","Change working directory","cd [dir]","cd /etc",cd},
{"pwd","Print current directory","pwd","pwd",pwd},
{"exit","Exit from shell()","exit","exit",xit},
{"set","Set environment variable","set [VAR=value]","set TERM=xterm",set},
{"unset","Unset environment variable","unset VAR","unset EDITOR",unset},
{"echo","Echo arguments on stdout","echo arg1 arg2 ...","echo Hello World!",echo},
{"env","Print all environment variables","env","env",env},
{".","Source-in a file with commands",". filename",". /etc/rc",sourcer},
{"?","Print this help :-)","? [command]","? set",help},
{NULL,NULL,NULL,NULL,NULL}
};
/*
* Built-in 'cd <path>' handler
*/
int
cd(char *path)
{
if(chdir(path)) return(-1);
getcwd(cwd,BUFSIZE);
return(0);
}
/*
* Built-in 'pwd' handler
*/
int
pwd(char *dummy)
{
if(getcwd(cwd,BUFSIZE)==NULL) return(-1);
printf("%s\n",cwd);
return(0);
}
/*
* Built-in 'exit' handler
*/
int
xit(char *dummy)
{
_exit(0);
}
/*
* Built-in 'echo' handler
*/
int
echo(char *args)
{
int i=0,j;
int len;
char c;
int s_quote=0,d_quote=0;
int sep=0,no_lf=0;
if(args==NULL) {
printf("\n");
return;
}
len=strlen(args);
if(len>=2) {
if(args[0]=='-' && args[1]=='n') {
no_lf++;
i=2;
while(i<len && (args[i]==' ' || args[i]=='\t')) i++;
}
}
while(i<len) {
c=args[i];
switch(c) {
case ' ':
case '\t':
if(s_quote||d_quote) {
putchar(c);
} else if(!sep) {
putchar(' ');
sep=1;
}
break;
case '\\':
i++;
c=args[i];
switch(c) {
case 'n':
putchar('\n');
break;
case 'b':
putchar('\b');
break;
case 't':
putchar('\t');
break;
case 'r':
putchar('\r');
break;
default:
putchar(c);
break;
}
break;
case '"':
if(!d_quote) {
d_quote=1;
for(j=i+1;j<len;j++) {
if(args[j]=='\\') {
j++;
continue;
}
if(args[j]=='"') {
d_quote=2;
break;
}
}
if(d_quote!=2) {
printf("\necho(): unmatched \"\n");
return;
}
} else d_quote=0;
break;
case '\'':
if(!s_quote) {
s_quote=1;
for(j=i+1;j<len;j++) {
if(args[j]=='\\') {
j++;
continue;
}
if(args[j]=='\'') {
s_quote=2;
break;
}
}
if(s_quote!=2) {
printf("\necho(): unmatched '\n");
return;
}
} else s_quote=0;
break;
case '`':
printf("echo(): backquote not implemented yet!\n");
break;
default:
sep=0;
putchar(c);
break;
}
i++;
}
if(!no_lf) putchar('\n');
fflush(stdout);
}
/*
* Built-in 'set VAR=value' handler
*/
int
set(char *var)
{
int res;
if(var==NULL) return(env(NULL));
res=putenv(var);
if(res) printf("set: %s\n",strerror(errno));
return(res);
}
/*
* Built-in 'env' handler
*/
int
env(char *dummy)
{
char **e;
e=environ;
while(*e!=NULL) {
printf("%s\n",*e++);
}
return(0);
}
/*
* Built-in 'unset VAR' handler
*/
int
unset(char *var)
{
if(var==NULL) {
printf("%s: parameter required.\n",progname);
return(-1);
}
return(unsetenv(var));
}
/*
* Built-in '?' handler
*/
int
help(char *cmd)
{
struct command *x;
int found=0;
if(cmd==NULL) {
printf("\nBuilt-in commands:\n");
printf("-------------------\n");
x=bltins;
while(x->cmd!=NULL) {
printf("%s\t%s\n",x->cmd,x->descr);
x++;
}
printf("\nEnter '? <cmd>' for details.\n\n");
return(0);
} else {
x=bltins;
while(x->cmd!=NULL) {
if(strcmp(x->cmd,cmd)==0) {
found++;
break;
}
x++;
}
if(found) {
printf("\n%s\t%s:\n",x->cmd,x->descr);
printf("\tUsage:\n\t\t%s\n",x->usage);
printf("\te.g:\n\t\t%s\n\n",x->example);
return(0);
} else {
printf("\n%s: no such command.\n\n",cmd);
return(-1);
}
}
}
/*
* Signal handler for shell()
*/
void
shell_sig(int sig)
{
switch(sig) {
case SIGINT:
case SIGQUIT:
case SIGTERM:
/* ignore ? */
break;
default:
break;
}
}
/*
* Built-in '.' handler (read-in and execute commands from file)
*/
int
sourcer(char *fname)
{
FILE *fd;
char buf[512],*tok,*arg,**av;
int ac,len,f,res,i;
pid_t pid;
char *sep=" \t";
fd=fopen(fname,"r");
if(fd==NULL) {
printf("Couldn't open file '%s'\n",fname);
return(-1);
}
while(!feof(fd)) {
memset(buf,0,512);
if(fgets(buf,512,fd)==NULL) continue;
if((*buf=='#') || (*buf=='\n')) continue;
len=strlen(buf);
buf[len-1]='\0';
if(strncmp(buf,"ncons",5)==0) {
tok=strtok(buf,sep);
tok=strtok(NULL,sep);
ncons=atoi(tok);
if((ncons<1)||(ncons>MAX_CONS)) {
syslog(LOG_EMERG,"%s: bad ncons value; defaulting to %d\n",fname,MAX_CONS);
ncons=MAX_CONS;
}
continue;
} else if(strncmp(buf,"motd",4)==0) {
tok=strtok(buf,sep);
motd=strdup(strtok(NULL,sep));
continue;
} else {
do_command(0,buf);
}
/* Next command, please. */
}
fclose(fd);
syslog(LOG_EMERG,"Done with %s",fname);
}
void
do_command(int shell, char *cmdline)
{
char *tok,*c,*sep=" \t";
char **av;
struct command *x;
int found,len;
int ac,i,f,res;
int bg=0;
pid_t pid;
len=strlen(cmdline);
if(cmdline[len-1]=='&') {
bg++;
cmdline[len-1]='\0';
len--;
} else bg=0;
tok=strtok(cmdline,sep);
x=bltins;
found=0;
while(x->cmd!=NULL) {
if(strcmp(x->cmd,tok)==0) {
found++;
break;
}
x++;
}
if(found) {
tok=cmdline+strlen(x->cmd)+1;
while(*tok && isblank(*tok) && (tok<(cmdline+len))) tok++;
if(*tok==NULL) tok=NULL;
x->func(tok);
return;
}
ac=0;
av=(char **)calloc(((len+1)/2+1),sizeof(char *));
av[ac++]=tok;
while((av[ac++]=strtok(NULL,sep))!=NULL)
continue;
switch((pid=fork())) {
case 0:
if(shell) {
signal(SIGINT,SIG_DFL);
signal(SIGQUIT,SIG_DFL);
signal(SIGTERM,SIG_DFL);
signal(SIGHUP,SIG_DFL);
} else {
close(0);
close(1);
close(2);
f=open(_PATH_CONSOLE,O_RDWR);
dup2(f,0);
dup2(f,1);
dup2(f,2);
if(f>2) close(f);
}
if(bg) {
if(daemon(0,0)) {
printf("do_command(%s): failed to run bg: %s\n",
av[0],strerror(errno));
_exit(100);
}
}
execvp(av[0],av);
/* Something went wrong... */
printf("do_command(%s): %s\n",av[0],strerror(errno));
_exit(100);
break;
case -1:
printf("do_command(): %s\n",strerror(errno));
break;
default:
while(waitpid(pid,&res,0)!=pid) continue;
if(WEXITSTATUS(res)) {
printf("do_command(%s): exit code=%d\n",
av[0],WEXITSTATUS(res));
}
break;
}
free(av);
return;
}
/*
* This is the user interface. This routine gets executed on each
* virtual console serviced by init.
*
* It works as normal shell does - for each external command it forks
* and execs, for each internal command just executes a function.
*/
int
shell(int argc, char **argv)
{
char buf[BUFSIZE];
char *prompt=" # ";
int fd;
int res;
pid_t mypid;
if(motd!=NULL) {
if((fd=open(motd,O_RDONLY))!=-1) {
do {
res=read(fd,buf,BUFSIZE);
res=write(1,buf,res);
} while(res>0);
close(fd);
}
}
printf("\n\n+=========================================================+\n");
printf("| Built-in shell() (enter '?' for short help on commands) |\n");
printf("+=========================================================+\n\n");
getcwd(cwd,BUFSIZE);
mypid=getpid();
signal(SIGINT,shell_sig);
signal(SIGQUIT,shell_sig);
signal(SIGTERM,shell_sig);
while(!feof(stdin)) {
memset(buf,0,BUFSIZE);
printf("(%d)%s%s",mypid,cwd,prompt);
fflush(stdout);
if(fgets(buf,BUFSIZE-1,stdin)==NULL) continue;
buf[strlen(buf)-1]='\0';
if(strlen(buf)==0) continue;
do_command(1,buf);
}
return(0);
}
/*
* Stub for executing some external program on a console. This is called
* from previously forked copy of our process, so that exec is ok.
*/
int
external_cmd(int argc, char **argv)
{
execvp(argv[0],argv);
}
/*
* Acquire vty and properly attach ourselves to it.
* Also, build basic environment for running user interface.
*/
int
start_session(int vty, int argc, char **argv)
{
int fd;
char *t;
close(0);
close(1);
close(2);
revoke(ttys[vty].tty);
fd=open(ttys[vty].tty,O_RDWR);
dup2(fd,0);
dup2(fd,1);
dup2(fd,2);
if(fd>2) close(fd);
login_tty(fd);
setpgid(0,getpid());
putenv("TERM=xterm");
putenv("HOME=/");
putenv("PATH=/stand:/bin:/usr/bin:/sbin:.");
signal(SIGHUP,SIG_DFL);
signal(SIGINT,SIG_DFL);
signal(SIGQUIT,SIG_DFL);
signal(SIGTERM,SIG_DFL);
chdir("/");
t=(char *)(rindex(ttys[vty].tty,'/')+1);
printf("\n\n\nStarting session on %s.\n",t);
ttys[vty].func(argc,argv);
_exit(0);
}
/*
* Execute system startup script /etc/rc
*
* (Of course if you don't like it - I don't - you can run anything you
* want here. Perhaps it would be useful just to read some config DB and
* do these things ourselves, avoiding forking lots of shells and scripts.)
*/
/* If OINIT_RC is defined, oinit will use it's own configuration file,
* /etc/oinit.rc. It's format is described below. Otherwise, it will use
* normal /etc/rc interpreted by Bourne shell.
*/
#ifndef OINIT_RC
#ifndef SH_NAME
#define SH_NAME "-sh"
#endif
#ifndef SH_PATH
#define SH_PATH _PATH_BSHELL
#endif
#ifndef SH_ARG
#define SH_ARG "/etc/rc"
#endif
void
runcom()
{
char *argv[3];
pid_t pid;
int st;
int fd;
if((pid=fork())==0) {
/* child */
close(0);
close(1);
close(2);
fd=open(_PATH_CONSOLE,O_RDWR);
dup2(fd,0);
dup2(fd,1);
dup2(fd,2);
if(fd>2) close(fd);
argv[0]=SH_NAME;
argv[1]=SH_ARG;
argv[2]=0;
execvp(SH_PATH,argv);
printf("runcom(): %s\n",strerror(errno));
_exit(1);
}
/* Wait for child to exit */
while(pid!=waitpid(pid,(int *)0,0)) continue;
return;
}
#else
/* Alternative /etc/rc - default is /etc/oinit.rc. Its format is as follows:
* - each empty line or line beginning with a '#' is discarded
* - any other line must contain a keyword, or a (nonblocking) command to run.
*
* Thus far, the following keywords are defined:
* ncons <number> number of virtual consoles to open
* motd <pathname> full path to motd file
*
* Examples of commands to run:
*
* ifconfig lo0 inet 127.0.0.1 netmask 255.0.0.0
* ifconfig ed0 inet 148.81.168.10 netmask 255.255.255.0
* kbdcontrol -l /usr/share/syscons/my_map.kbd
*/
void
runcom(char *fname)
{
int fd;
close(0);
close(1);
close(2);
fd=open(_PATH_CONSOLE,O_RDWR);
dup2(fd,0);
dup2(fd,1);
dup2(fd,2);
if(fd>2) close(fd);
sourcer(fname);
}
#endif
int
run_multi()
{
int i,j;
pid_t pid;
int found;
/* Run /etc/rc if not in single user */
#ifndef OINIT_RC
if(prevtrans==SINGLE) runcom();
#else
if(prevtrans==SINGLE) runcom(OINIT_RC);
#endif
if(transition!=MULTI) return(-1);
syslog(LOG_EMERG,"*** Starting multi-user mode ***");
/* Fork shell interface for each console */
for(i=0;i<ncons;i++) {
if(ttys[i].pid==0) {
switch(pid=fork()) {
case 0:
start_session(i,0,NULL);
break;
case -1:
printf("%s: %s\n",progname,strerror(errno));
break;
default:
ttys[i].pid=pid;
break;
}
}
}
/* Initialize any other services we'll use - most probably this will
* be a 'telnet' service (some day...).
*/
/* */
/* Emulate multi-user */
while(transition==MULTI) {
/* XXX Modify this to allow for checking for the input on
* XXX listening sockets, and forking a 'telnet' service.
*/
/* */
/* Wait for any process to exit */
pid=waitpid(-1,(int *)0,0);
if(pid==-1) continue;
found=0;
j=-1;
/* search if it's one of our sessions */
for(i=0;i<ncons;i++) {
if(ttys[i].pid==pid) {
found++;
j=i;
ttys[j].pid=0;
break;
}
}
if(!found) {
/* Just collect the process's status */
continue;
} else {
/* restart shell() on a console, if it died */
if(transition!=MULTI) return(0);
switch(pid=fork()) {
case 0:
sleep(1);
start_session(j,0,NULL);
break;
case -1:
printf("%s: %s\n",progname,strerror(errno));
break;
default:
ttys[j].pid=pid;
break;
}
}
}
}
int clang;
void
kill_timer(int sig)
{
clang=1;
}
kill_ttys()
{
}
/*
* Start a shell on ttyv0 (i.e. the console).
*/
int
run_single()
{
int i;
pid_t pid,wpid;
static int sigs[2]={SIGTERM,SIGKILL};
syslog(LOG_EMERG,"*** Starting single-user mode ***");
/* Kill all existing sessions */
syslog(LOG_EMERG,"Killing all existing sessions...");
for(i=0;i<MAX_CONS;i++) {
kill(ttys[i].pid,SIGHUP);
ttys[i].pid=0;
}
for(i=0;i<2;i++) {
if(kill(-1,sigs[i])==-1 && errno==ESRCH) break;
clang=0;
alarm(10);
do {
pid=waitpid(-1,(int *)0,WUNTRACED);
if(errno==EINTR) continue;
else break;
} while (clang==0);
}
if(errno!=ECHILD) {
syslog(LOG_EMERG,"Some processes would not die; ps -axl advised");
}
/* Single-user */
switch(pid=fork()) {
case 0:
start_session(0,0,NULL);
break;
case -1:
printf("%s: %s\n",progname,strerror(errno));
printf("The system is seriously hosed. I'm dying...\n");
transition=DEATH;
return(-1);
break;
default:
do {
wpid=waitpid(pid,(int *)0,WUNTRACED);
} while(wpid!=pid && transition==SINGLE);
if(transition!=DEATH) {
prevtrans=transition;
transition=MULTI;
}
break;
}
return(0);
}
/*
* Transition handler - installed as signal handler.
*/
void
transition_handler(int sig)
{
switch(sig) {
case SIGHUP:
case SIGTERM:
prevtrans=transition;
transition=SINGLE;
syslog(LOG_EMERG,"*** Going from %s -> %s\n",trans[prevtrans],trans[transition]);
if(prevtrans!=transition) longjmp(machine,sig);
break;
case SIGINT:
case SIGQUIT:
prevtrans=transition;
transition=DEATH;
syslog(LOG_EMERG,"*** Going from %s -> %s\n",trans[prevtrans],trans[transition]);
if(prevtrans!=transition) longjmp(machine,sig);
break;
default:
syslog(LOG_EMERG,"pid=%d sig=%s (ignored)\n",getpid(),sys_siglist[sig]);
break;
}
}
/*
* Change system state appropriately to the signals
*/
int
transition_machine()
{
int i;
while(transition!=DEATH) {
switch(transition) {
case MULTI:
run_multi();
break;
case SINGLE:
run_single();
break;
}
}
syslog(LOG_EMERG,"Killing all existing sessions...");
/* Kill all sessions */
kill(-1,SIGKILL);
/* Be nice and wait for them */
while(waitpid(-1,(int *)0,WNOHANG|WUNTRACED)>0) continue;
unmount("/",0);
reboot(RB_AUTOBOOT);
/* NOTREACHED */
}
int
main(int argc, char **argv)
{
int devfs=0,c,i;
/* These are copied from real init(8) */
if(getuid()!=0)
errx(1,"%s",strerror(EPERM));
openlog("init",LOG_CONS|LOG_ODELAY,LOG_AUTH);
if(setsid()<0)
warn("initial setsid() failed");
if(setlogin("root")<0)
warn("setlogin() failed");
close(0);
close(1);
close(2);
chdir("/");
progname=rindex(argv[0],'/');
if(progname==NULL) {
progname=argv[0];
} else progname++;
transition=MULTI;
/* We must recognize the same options as real init does */
while((c=getopt(argc,argv,"dsf"))!=-1) {
switch(c) {
case 'd':
devfs=1;
break;
case 's':
transition=SINGLE;
break;
case 'f':
break;
default:
printf("%s: unrecognized flag '-%c'\n",progname,c);
break;
}
}
if(devfs)
mount("devfs",_PATH_DEV,MNT_NOEXEC|MNT_RDONLY,0);
/* Fill in the sess structures. */
/* XXX Really, should be filled based upon config file. */
for(i=0;i<MAX_CONS;i++) {
if(i==0) {
sprintf(ttys[i].tty,_PATH_CONSOLE);
} else {
sprintf(ttys[i].tty,"%sv%c",_PATH_TTY,vty[i]);
}
ttys[i].pid=0;
ttys[i].func=shell;
}
getcwd(cwd,BUFSIZE);
signal(SIGINT,transition_handler);
signal(SIGQUIT,transition_handler);
signal(SIGTERM,transition_handler);
signal(SIGHUP,transition_handler);
signal(SIGALRM,kill_timer);
setjmp(machine);
transition_machine(transition);
/* NOTREACHED */
exit(100);
}
