static List *backq(Node *ifs, Node *n) {
int p[2], sp;
pid_t pid;
List *bq;
struct termios t;
if (n == NULL)
return NULL;
if (pipe(p) < 0) {
uerror("pipe");
rc_error(NULL);
}
if (interactive)
tcgetattr(0, &t);
if ((pid = rc_fork()) == 0) {
mvfd(p[1], 1);
close(p[0]);
redirq = NULL;
walk(n, FALSE);
exit(getstatus());
}
close(p[1]);
bq = bqinput(glom(ifs), p[0]);
close(p[0]);
rc_wait4(pid, &sp, TRUE);
if (interactive && WIFSIGNALED(sp))
tcsetattr(0, TCSANOW, &t);
statprint(-1, sp);
varassign("bqstatus", word(strstatus(sp), NULL), FALSE);
sigchk();
return bq;
}
static bool dofork(bool parent) {
int pid, sp;
if (!parent || (pid = rc_fork()) == 0)
return TRUE;
redirq = NULL; /* clear out the pre-redirection queue in the parent */
rc_wait4(pid, &sp, TRUE);
setstatus(-1, sp);
sigchk();
return FALSE;
}
static void dopipe(Node *n) {
int i, j, sp, pid, fd_prev, fd_out, pids[512], stats[512], p[2];
bool intr;
Node *r;
fd_prev = fd_out = 1;
for (r = n, i = 0; r != NULL && r->type == nPipe; r = r->u[2].p, i++) {
if (i > 500) /* the only hard-wired limit in rc? */
rc_error("pipe too long");
if (pipe(p) < 0) {
uerror("pipe");
rc_error(NULL);
}
if ((pid = rc_fork()) == 0) {
setsigdefaults(FALSE);
redirq = NULL; /* clear preredir queue */
mvfd(p[0], r->u[1].i);
if (fd_prev != 1)
mvfd(fd_prev, fd_out);
close(p[1]);
walk(r->u[3].p, FALSE);
exit(getstatus());
}
if (fd_prev != 1)
close(fd_prev); /* parent must close all pipe fd's */
pids[i] = pid;
fd_prev = p[1];
fd_out = r->u[0].i;
close(p[0]);
}
if ((pid = rc_fork()) == 0) {
setsigdefaults(FALSE);
mvfd(fd_prev, fd_out);
walk(r, FALSE);
exit(getstatus());
/* NOTREACHED */
}
redirq = NULL; /* clear preredir queue */
close(fd_prev);
pids[i++] = pid;
/* collect statuses */
intr = FALSE;
for (j = 0; j < i; j++) {
rc_wait4(pids[j], &sp, TRUE);
stats[j] = sp;
intr |= (sp == SIGINT);
}
setpipestatus(stats, i);
sigchk();
}
static void b_wait(char **av) {
int status;
pid_t pid;
if (av[1] == NULL) {
waitforall();
return;
}
if (av[2] != NULL) {
arg_count("wait");
return;
}
if ((pid = a2u(av[1])) < 0) {
badnum(av[1]);
return;
}
if (rc_wait4(pid, &status, FALSE) > 0)
setstatus(pid, status);
else
set(FALSE);
sigchk();
}
extern void exec(List *s, bool parent) {
char **av, **ev = NULL;
int pid, stat;
builtin_t *b;
char *path = NULL;
bool didfork, returning, saw_exec, saw_builtin;
av = list2array(s, dashex);
saw_builtin = saw_exec = FALSE;
do {
if (*av == NULL || isabsolute(*av))
b = NULL;
else if (!saw_builtin && fnlookup(*av) != NULL)
b = funcall;
else
b = isbuiltin(*av);
/*
a builtin applies only to the immmediately following
command, e.g., builtin exec echo hi
*/
saw_builtin = FALSE;
if (b == b_exec) {
av++;
saw_exec = TRUE;
parent = FALSE;
} else if (b == b_builtin) {
av++;
saw_builtin = TRUE;
}
} while (b == b_exec || b == b_builtin);
if (*av == NULL && saw_exec) { /* do redirs and return on a null exec */
doredirs();
return;
}
/* force an exit on exec with any rc_error, but not for null commands as above */
if (saw_exec)
rc_pid = -1;
if (b == NULL) {
path = which(*av, TRUE);
if (path == NULL && *av != NULL) { /* perform null commands for redirections */
set(FALSE);
redirq = NULL;
if (parent)
return;
rc_exit(1);
}
ev = makeenv(); /* environment only needs to be built for execve() */
}
/*
If parent & the redirq is nonnull, builtin or not it has to fork.
If the fifoq is nonnull, then it must be emptied at the end so we
must fork no matter what.
*/
if ((parent && (b == NULL || redirq != NULL)) || outstanding_cmdarg()) {
pid = rc_fork();
didfork = TRUE;
} else {
pid = 0;
didfork = FALSE;
}
returning = (!didfork && parent);
switch (pid) {
case -1:
uerror("fork");
rc_error(NULL);
/* NOTREACHED */
case 0:
if (!returning)
setsigdefaults(FALSE);
pop_cmdarg(FALSE);
doredirs();
/* null commands performed for redirections */
if (*av == NULL || b != NULL) {
if (b != NULL)
(*b)(av);
if (returning)
return;
rc_exit(getstatus());
}
execve(path, (char * const *) av, (char * const *) ev);
uerror(*av);
rc_exit(1);
/* NOTREACHED */
default:
redirq = NULL;
rc_wait4(pid, &stat, TRUE);
setstatus(-1, stat);
if ((stat & 0xff) == 0)
nl_on_intr = FALSE;
SIGCHK;
nl_on_intr = TRUE;
pop_cmdarg(TRUE);
}
}
