jehanne/sys/src/lib/thread/exec.c

111 lines
2.6 KiB
C

/*
* 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 <u.h>
#include <libc.h>
#include <thread.h>
#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){
jehanne_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(sys_bind("#|", PIPEMNT, MREPL) < 0)
goto Bad;
if((p->exec.fd[0] = sys_open(PIPEMNT "/data", OREAD)) < 0){
sys_unmount(nil, PIPEMNT);
goto Bad;
}
if((p->exec.fd[1] = sys_open(PIPEMNT "/data1", OWRITE|OCEXEC)) < 0){
sys_close(p->exec.fd[0]);
sys_unmount(nil, PIPEMNT);
goto Bad;
}
sys_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();
sys_close(p->exec.fd[1]);
if((n = jehanne_read(p->exec.fd[0], p->exitstr, ERRMAX-1)) > 0){ /* exec failed */
p->exitstr[n] = '\0';
sys_errstr(p->exitstr, ERRMAX);
sys_close(p->exec.fd[0]);
goto Bad;
}
sys_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, ...)
{
va_list va, va2;
char *arg;
int n;
va_start(va, f);
va_copy(va2, va);
n = 0;
while((arg = va_arg(va, char *)) != nil)
n++;
char **args = jehanne_malloc(sizeof(char*)*(n+1));
n = 0;
while((arg = va_arg(va2, char *)) != nil)
args[n++] = arg;
args[n] = nil;
va_end(va);
va_end(va2);
procexec(pidc, f, args);
}