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#include <u.h>
#include <signal.h>
#if defined(PLAN9PORT) && defined(__sun__)
# define BSD_COMP /* sigh. for TIOCNOTTY */
#endif
#include <sys/ioctl.h>
#include "rc.h"
#include "getflags.h"
#include "exec.h"
#include "io.h"
#include "fns.h"
int havefork = 1;
void
Xasync(void)
{
int null = open("/dev/null", 0);
int tty;
int pid;
char npid[10];
if(null<0){
Xerror("Can't open /dev/null\n");
return;
}
switch(pid = rfork(RFFDG|RFPROC|RFNOTEG)){
case -1:
close(null);
Xerror("try again");
break;
case 0:
clearwaitpids();
/*
* I don't know what the right thing to do here is,
* so this is all experimentally determined.
* If we just dup /dev/null onto 0, then running
* ssh foo & will reopen /dev/tty, try to read a password,
* get a signal, and repeat, in a tight loop, forever.
* Arguably this is a bug in ssh (it behaves the same
* way under bash as under rc) but I'm fixing it here
* anyway. If we dissociate the process from the tty,
* then it won't be able to open /dev/tty ever again.
* The SIG_IGN on SIGTTOU makes writing the tty
* (via fd 1 or 2, for example) succeed even though
* our pgrp is not the terminal's controlling pgrp.
*/
if((tty = open("/dev/tty", OREAD)) >= 0){
/*
* Should make reads of tty fail, writes succeed.
*/
signal(SIGTTIN, SIG_IGN);
signal(SIGTTOU, SIG_IGN);
ioctl(tty, TIOCNOTTY);
close(tty);
}
if(isatty(0))
pushredir(ROPEN, null, 0);
else
close(null);
start(runq->code, runq->pc+1, runq->local);
runq->ret = 0;
break;
default:
addwaitpid(pid);
close(null);
runq->pc = runq->code[runq->pc].i;
inttoascii(npid, pid);
setvar("apid", newword(npid, (word *)0));
break;
}
}
void
Xpipe(void)
{
struct thread *p = runq;
int pc = p->pc, forkid;
int lfd = p->code[pc++].i;
int rfd = p->code[pc++].i;
int pfd[2];
if(pipe(pfd)<0){
Xerror("can't get pipe");
return;
}
switch(forkid = fork()){
case -1:
Xerror("try again");
break;
case 0:
clearwaitpids();
start(p->code, pc+2, runq->local);
runq->ret = 0;
close(pfd[PRD]);
pushredir(ROPEN, pfd[PWR], lfd);
break;
default:
addwaitpid(forkid);
start(p->code, p->code[pc].i, runq->local);
close(pfd[PWR]);
pushredir(ROPEN, pfd[PRD], rfd);
p->pc = p->code[pc+1].i;
p->pid = forkid;
break;
}
}
/*
* Who should wait for the exit from the fork?
*/
void
Xbackq(void)
{
struct thread *p = runq;
char wd[8193];
int c;
char *s, *ewd=&wd[8192], *stop;
struct io *f;
var *ifs = vlook("ifs");
word *v, *nextv;
int pfd[2];
int pid;
stop = ifs->val?ifs->val->word:"";
if(pipe(pfd)<0){
Xerror("can't make pipe");
return;
}
switch(pid = fork()){
case -1:
Xerror("try again");
close(pfd[PRD]);
close(pfd[PWR]);
return;
case 0:
clearwaitpids();
close(pfd[PRD]);
start(runq->code, runq->pc+1, runq->local);
pushredir(ROPEN, pfd[PWR], 1);
return;
default:
addwaitpid(pid);
close(pfd[PWR]);
f = openfd(pfd[PRD]);
s = wd;
v = 0;
while((c = rchr(f))!=EOF){
if(strchr(stop, c) || s==ewd){
if(s!=wd){
*s='\0';
v = newword(wd, v);
s = wd;
}
}
else *s++=c;
}
if(s!=wd){
*s='\0';
v = newword(wd, v);
}
closeio(f);
Waitfor(pid, 0);
/* v points to reversed arglist -- reverse it onto argv */
while(v){
nextv = v->next;
v->next = runq->argv->words;
runq->argv->words = v;
v = nextv;
}
p->pc = p->code[p->pc].i;
return;
}
}
void
Xpipefd(void)
{
struct thread *p = runq;
int pc = p->pc, pid;
char name[40];
int pfd[2];
int sidefd, mainfd;
if(pipe(pfd)<0){
Xerror("can't get pipe");
return;
}
if(p->code[pc].i==READ){
sidefd = pfd[PWR];
mainfd = pfd[PRD];
}
else{
sidefd = pfd[PRD];
mainfd = pfd[PWR];
}
switch(pid = fork()){
case -1:
Xerror("try again");
break;
case 0:
clearwaitpids();
start(p->code, pc+2, runq->local);
close(mainfd);
pushredir(ROPEN, sidefd, p->code[pc].i==READ?1:0);
runq->ret = 0;
break;
default:
addwaitpid(pid);
close(sidefd);
pushredir(ROPEN, mainfd, mainfd); /* isn't this a noop? */
strcpy(name, Fdprefix);
inttoascii(name+strlen(name), mainfd);
pushword(name);
p->pc = p->code[pc+1].i;
break;
}
}
void
Xsubshell(void)
{
int pid;
switch(pid = fork()){
case -1:
Xerror("try again");
break;
case 0:
clearwaitpids();
start(runq->code, runq->pc+1, runq->local);
runq->ret = 0;
break;
default:
addwaitpid(pid);
Waitfor(pid, 1);
runq->pc = runq->code[runq->pc].i;
break;
}
}
int
execforkexec(void)
{
int pid;
int n;
char buf[ERRMAX];
switch(pid = fork()){
case -1:
return -1;
case 0:
clearwaitpids();
pushword("exec");
execexec();
strcpy(buf, "can't exec: ");
n = strlen(buf);
errstr(buf+n, ERRMAX-n);
Exit(buf);
}
addwaitpid(pid);
return pid;
}
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