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#include "threadimpl.h"
#define PIPEMNT "/mnt/temp"
void
procexec(Channel *pidc, char *prog, char *args[])
{
int n;
Proc *p;
Thread *t;
_threaddebug(DBGEXEC, "procexec %s", prog);
/* must be only thread in proc */
p = _threadgetproc();
t = p->thread;
if(p->threads.head != t || p->threads.head->nextt != nil){
werrstr("not only thread in proc");
Bad:
if(pidc)
sendul(pidc, ~0);
return;
}
/*
* We want procexec to behave like exec; if exec succeeds,
* never return, and if it fails, return with errstr set.
* Unfortunately, the exec happens in another proc since
* we have to wait for the exec'ed process to finish.
* To provide the semantics, we open a pipe with the
* write end close-on-exec and hand it to the proc that
* is doing the exec. If the exec succeeds, the pipe will
* close so that our read below fails. If the exec fails,
* then the proc doing the exec sends the errstr down the
* pipe to us.
*/
if(bind("#|", PIPEMNT, MREPL) < 0)
goto Bad;
if((p->exec.fd[0] = open(PIPEMNT "/data", OREAD)) < 0){
unmount(nil, PIPEMNT);
goto Bad;
}
if((p->exec.fd[1] = open(PIPEMNT "/data1", OWRITE|OCEXEC)) < 0){
close(p->exec.fd[0]);
unmount(nil, PIPEMNT);
goto Bad;
}
unmount(nil, PIPEMNT);
/* exec in parallel via the scheduler */
assert(p->needexec==0);
p->exec.prog = prog;
p->exec.args = args;
p->needexec = 1;
_sched();
close(p->exec.fd[1]);
if((n = read(p->exec.fd[0], p->exitstr, ERRMAX-1)) > 0){ /* exec failed */
p->exitstr[n] = '\0';
errstr(p->exitstr, ERRMAX);
close(p->exec.fd[0]);
goto Bad;
}
close(p->exec.fd[0]);
if(pidc)
sendul(pidc, t->ret);
/* wait for exec'ed program, then exit */
_schedexecwait();
}
void
procexecl(Channel *pidc, char *f, ...)
{
procexec(pidc, f, &f+1);
}
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