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- /*
- * This file is part of the UCB release of Plan 9. It is subject to the license
- * terms in the LICENSE file found in the top-level directory of this
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
- * part of the UCB release of Plan 9, including this file, may be copied,
- * modified, propagated, or distributed except according to the terms contained
- * in the LICENSE file.
- */
- #include "rc.h"
- #include "getflags.h"
- #include "exec.h"
- #include "io.h"
- #include "fns.h"
- #include <String.h>
- int havefork = 1;
- void
- Xasync(void)
- {
- int null = open("/dev/null", 0);
- 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();
- pushredir(ROPEN, null, 0);
- 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)
- {
- int n, pid;
- int pfd[2];
- char *stop;
- char utf[UTFmax+1];
- struct io *f;
- var *ifs = vlook("ifs");
- word *v, *nextv;
- Rune r;
- String *word;
- 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]);
- word = s_new();
- v = nil;
- /* rutf requires at least UTFmax+1 bytes in utf */
- while((n = rutf(f, utf, &r)) != EOF){
- utf[n] = '\0';
- if(utfutf(stop, utf) == nil)
- s_nappend(word, utf, n);
- else
- /*
- * utf/r is an ifs rune (e.g., \t, \n), thus
- * ends the current word, if any.
- */
- if(s_len(word) > 0){
- v = newword(s_to_c(word), v);
- s_reset(word);
- }
- }
- if(s_len(word) > 0)
- v = newword(s_to_c(word), v);
- s_free(word);
- 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;
- }
- runq->pc = runq->code[runq->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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