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#include "dat.h"
#include "fns.h"
#include "error.h"
extern void vstack(void*);
/*
* all this is for the benefit of devcmd.
* i hope it's grateful.
*/
typedef struct Targ Targ;
struct Targ
{
int fd[3]; /* standard input, output and error */
int wfd;
int* spin;
char** args;
char* dir;
int pid;
int nice;
};
/*
* called by vstack once it has moved to
* the unshared stack in the new process.
*/
void
exectramp(Targ *t)
{
int *fd, i, nfd;
char filename[128], err[ERRMAX], status[2*ERRMAX];
t->pid = getpid();
*t->spin = 0; /* allow parent to proceed: can't just rendezvous: see below */
fd = t->fd;
snprint(filename, sizeof(filename), "#d/%d", t->wfd);
t->wfd = open(filename, OWRITE|OCEXEC);
/* if it failed, we'll manage */
nfd = MAXNFD; /* TO DO: should read from /fd */
for(i = 0; i < nfd; i++)
if(i != fd[0] && i != fd[1] && i != fd[2] && i != t->wfd)
close(i);
if(fd[0] != 0){
dup(fd[0], 0);
close(fd[0]);
}
if(fd[1] != 1){
dup(fd[1], 1);
close(fd[1]);
}
if(fd[2] != 2){
dup(fd[2], 2);
close(fd[2]);
}
if(t->dir != nil && chdir(t->dir) < 0){
if(t->wfd > 0)
fprint(t->wfd, "chdir: %s: %r", t->dir);
_exits("bad dir");
}
if(t->nice)
oslopri();
exec(t->args[0], t->args);
err[0] = 0;
errstr(err, sizeof(err));
if(t->args[0][0] != '/' && t->args[0][0] != '#' &&
strncmp(t->args[0], "../", 3) != 0 && strncmp(t->args[0], "./", 2) != 0 &&
strlen(t->args[0])+5 < sizeof(filename)){
snprint(filename, sizeof(filename), "/bin/%s", t->args[0]);
exec(filename, t->args);
errstr(err, sizeof(err));
}
snprint(status, sizeof(status), "%s: can't exec: %s", t->args[0], err);
if(t->wfd > 0)
write(t->wfd, status, strlen(status));
_exits(status);
}
void*
oscmd(char **args, int nice, char *dir, int *fd)
{
Targ *t;
int spin, *spinptr, fd0[2], fd1[2], fd2[2], wfd[2], n;
Dir *d;
up->genbuf[0] = 0;
t = mallocz(sizeof(*t), 1);
if(t == nil)
return nil;
t->args = args;
t->dir = dir;
t->nice = nice;
fd0[0] = fd0[1] = -1;
fd1[0] = fd1[1] = -1;
fd2[0] = fd2[1] = -1;
wfd[0] = wfd[1] = -1;
if(dir != nil){
d = dirstat(dir);
if(d == nil)
goto Error;
free(d);
}
if(pipe(fd0) < 0 || pipe(fd1) < 0 || pipe(fd2) < 0 || pipe(wfd) < 0)
goto Error;
spinptr = &spin;
spin = 1;
t->fd[0] = fd0[0];
t->fd[1] = fd1[1];
t->fd[2] = fd2[1];
t->wfd = wfd[1];
t->spin = spinptr;
switch(rfork(RFPROC|RFMEM|RFREND|RFNOTEG|RFFDG|RFNAMEG|RFENVG)) {
case -1:
goto Error;
case 0:
/* if child returns first from rfork, its call to vstack replaces ... */
vstack(t);
/* ... parent's return address from rfork and parent returns here */
default:
/* if parent returns first from rfork, it comes here */
/* can't call anything: on shared stack until child releases spin in exectramp */
while(*spinptr)
;
break;
}
close(fd0[0]);
close(fd1[1]);
close(fd2[1]);
close(wfd[1]);
n = read(wfd[0], up->genbuf, sizeof(up->genbuf)-1);
close(wfd[0]);
if(n > 0){
close(fd0[1]);
close(fd1[0]);
close(fd2[0]);
up->genbuf[n] = 0;
errstr(up->genbuf, sizeof(up->genbuf));
free(t);
return nil;
}
fd[0] = fd0[1];
fd[1] = fd1[0];
fd[2] = fd2[0];
return t;
Error:
errstr(up->genbuf, sizeof(up->genbuf)); /* save the message before close */
close(fd0[0]);
close(fd0[1]);
close(fd1[0]);
close(fd1[1]);
close(fd2[0]);
close(fd2[1]);
close(wfd[0]);
close(wfd[1]);
free(t);
errstr(up->genbuf, sizeof(up->genbuf));
return nil;
}
int
oscmdkill(void *a)
{
Targ *t = a;
return postnote(PNGROUP, t->pid, "kill");
}
int
oscmdwait(void*, char *buf, int n)
{
return await(buf, n);
}
void
oscmdfree(void *a)
{
free(a);
}
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