ref: 1fe3143e4c43ce2c74e0cfdd70b1bd556bbb9e1b
dir: /sys/src/cmd/rc/havefork.c/
#include "rc.h" #include "getflags.h" #include "exec.h" #include "io.h" #include "fns.h" 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; } Updenv(); 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; } Updenv(); 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? */ enum { Stralloc = 100, }; void Xbackq(void) { int c, l, pid; int pfd[2]; char *s, *wd, *ewd, *stop; struct io *f; word *v, *nextv; stop = ""; if(runq->argv && runq->argv->words) stop = runq->argv->words->word; if(pipe(pfd)<0){ Xerror("can't make pipe"); return; } Updenv(); 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 = ewd = 0; v = 0; while((c = rchr(f))!=EOF){ if(s==ewd){ l = s-wd; wd = erealloc(wd, l+Stralloc); ewd = wd+l+Stralloc-1; s = wd+l; } if(strchr(stop, c)){ if(s!=wd){ *s='\0'; v = newword(wd, v); s = wd; } } else *s++=c; } if(s!=wd){ *s='\0'; v = newword(wd, v); } free(wd); closeio(f); Waitfor(pid, 0); poplist(); /* ditch split in "stop" */ /* 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]; } Updenv(); 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); shuffleredir(); /* shuffle redir to bottom of stack for turfredir() */ strcpy(name, Fdprefix); inttoascii(name+strlen(name), mainfd); pushword(name); p->pc = p->code[pc+1].i; break; } } void Xsubshell(void) { int pid; Updenv(); 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; }