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;
}
extern void assign(List *s1, List *s2, bool stack) {
List *val = s2;
if (s1 == NULL)
rc_error("null variable name");
if (s1->n != NULL)
rc_error("multi-word variable name");
if (*s1->w == '\0')
rc_error("zero-length variable name");
if (a2u(s1->w) != -1)
rc_error("numeric variable name");
if (strchr(s1->w, '=') != NULL)
rc_error("'=' in variable name");
if (*s1->w == '*' && s1->w[1] == '\0')
val = append(varlookup("0"), s2); /* preserve $0 when * is assigned explicitly */
if (s2 != NULL || stack) {
if (dashex)
prettyprint_var(2, s1->w, val);
varassign(s1->w, val, stack);
alias(s1->w, varlookup(s1->w), stack);
} else {
if (dashex)
prettyprint_var(2, s1->w, NULL);
varrm(s1->w, stack);
}
}
static void b_shift(char **av) {
int shift = (av[1] == NULL ? 1 : a2u(av[1]));
List *s, *dollarzero;
if (av[1] != NULL && av[2] != NULL) {
arg_count("shift");
return;
}
if (shift < 0) {
badnum(av[1]);
return;
}
s = varlookup("*")->n;
dollarzero = varlookup("0");
while (s != NULL && shift != 0) {
s = s->n;
--shift;
}
if (s == NULL && shift != 0) {
fprint(2, "cannot shift\n");
set(FALSE);
} else {
varassign("*", append(dollarzero, s), FALSE);
set(TRUE);
}
}
static void update_cwd_var(void)
{
char b[PATH_MAX+1];
List val;
const char* ret = getcwd(b, arraysize(b) - 1);
if (ret) {
val.w = nprint("%s", b);
val.n = NULL;
varassign("pwd", &val, FALSE);
}
}
extern bool walk(Node *n, bool parent) {
top: sigchk();
if (n == NULL) {
if (!parent)
exit(0);
set(TRUE);
return TRUE;
}
switch (n->type) {
case nArgs: case nBackq: case nConcat: case nCount:
case nFlat: case nLappend: case nRedir: case nVar:
case nVarsub: case nWord:
exec(glob(glom(n)), parent); /* simple command */
break;
case nBody:
walk(n->u[0].p, TRUE);
WALK(n->u[1].p, parent);
/* WALK doesn't fall through */
case nNowait: {
int pid;
if ((pid = rc_fork()) == 0) {
#if defined(RC_JOB) && defined(SIGTTOU) && defined(SIGTTIN) && defined(SIGTSTP)
setsigdefaults(FALSE);
rc_signal(SIGTTOU, SIG_IGN); /* Berkeleyized version: put it in a new pgroup. */
rc_signal(SIGTTIN, SIG_IGN);
rc_signal(SIGTSTP, SIG_IGN);
setpgid(0, getpid());
#else
setsigdefaults(TRUE); /* ignore SIGINT, SIGQUIT, SIGTERM */
#endif
mvfd(rc_open("/dev/null", rFrom), 0);
walk(n->u[0].p, FALSE);
exit(getstatus());
}
if (interactive)
fprint(2, "%d\n", pid);
varassign("apid", word(nprint("%d", pid), NULL), FALSE);
redirq = NULL; /* kill pre-redir queue */
break;
}
case nAndalso: {
bool oldcond = cond;
cond = TRUE;
if (walk(n->u[0].p, TRUE)) {
cond = oldcond;
WALK(n->u[1].p, parent);
} else
cond = oldcond;
break;
}
case nOrelse: {
bool oldcond = cond;
cond = TRUE;
if (!walk(n->u[0].p, TRUE)) {
cond = oldcond;
WALK(n->u[1].p, parent);
} else
cond = oldcond;
break;
}
case nBang:
set(!walk(n->u[0].p, TRUE));
break;
case nIf: {
bool oldcond = cond;
Node *true_cmd = n->u[1].p, *false_cmd = NULL;
if (true_cmd != NULL && true_cmd->type == nElse) {
false_cmd = true_cmd->u[1].p;
true_cmd = true_cmd->u[0].p;
}
cond = TRUE;
if (!walk(n->u[0].p, TRUE))
true_cmd = false_cmd; /* run the else clause */
cond = oldcond;
WALK(true_cmd, parent);
}
case nWhile: {
Jbwrap j;
Edata jbreak;
Estack e1, e2;
bool testtrue, oldcond = cond;
cond = TRUE;
if (!walk(n->u[0].p, TRUE)) { /* prevent spurious breaks inside test */
cond = oldcond;
break;
}
if (sigsetjmp(j.j, 1))
break;
jbreak.jb = &j;
except(eBreak, jbreak, &e1);
do {
Edata block;
block.b = newblock();
cond = oldcond;
except(eArena, block, &e2);
walk(n->u[1].p, TRUE);
testtrue = walk(n->u[0].p, TRUE);
unexcept(); /* eArena */
cond = TRUE;
} while (testtrue);
cond = oldcond;
unexcept(); /* eBreak */
break;
}
case nForin: {
List *l, *var = glom(n->u[0].p);
Jbwrap j;
Estack e1, e2;
Edata jbreak;
if (sigsetjmp(j.j, 1))
break;
jbreak.jb = &j;
except(eBreak, jbreak, &e1);
for (l = listcpy(glob(glom(n->u[1].p)), nalloc); l != NULL; l = l->n) {
Edata block;
assign(var, word(l->w, NULL), FALSE);
block.b = newblock();
except(eArena, block, &e2);
walk(n->u[2].p, TRUE);
unexcept(); /* eArena */
}
unexcept(); /* eBreak */
break;
}
case nSubshell:
if (dofork(TRUE)) {
setsigdefaults(FALSE);
walk(n->u[0].p, FALSE);
rc_exit(getstatus());
}
break;
case nAssign:
if (n->u[0].p == NULL)
rc_error("null variable name");
assign(glom(n->u[0].p), glob(glom(n->u[1].p)), FALSE);
set(TRUE);
break;
case nPipe:
dopipe(n);
break;
case nNewfn: {
List *l = glom(n->u[0].p);
if (l == NULL)
rc_error("null function name");
while (l != NULL) {
if (dashex)
prettyprint_fn(2, l->w, n->u[1].p);
fnassign(l->w, n->u[1].p);
l = l->n;
}
set(TRUE);
break;
}
case nRmfn: {
List *l = glom(n->u[0].p);
while (l != NULL) {
if (dashex)
fprint(2, "fn %S\n", l->w);
fnrm(l->w);
l = l->n;
}
set(TRUE);
break;
}
case nDup:
redirq = NULL;
break; /* Null command */
case nMatch: {
List *a = glob(glom(n->u[0].p)), *b = glom(n->u[1].p);
if (dashex)
fprint(2, (a != NULL && a->n != NULL) ? "~ (%L) %L\n" : "~ %L %L\n", a, " ", b, " ");
set(lmatch(a, b));
break;
}
case nSwitch: {
List *v = glom(n->u[0].p);
while (1) {
do {
n = n->u[1].p;
if (n == NULL)
return istrue();
} while (n->u[0].p == NULL || n->u[0].p->type != nCase);
if (lmatch(v, glom(n->u[0].p->u[0].p))) {
for (n = n->u[1].p; n != NULL && (n->u[0].p == NULL || n->u[0].p->type != nCase); n = n->u[1].p)
walk(n->u[0].p, TRUE);
break;
}
}
break;
}
case nPre: {
List *v;
if (n->u[0].p->type == nRedir || n->u[0].p->type == nDup) {
if (redirq == NULL && !dofork(parent)) /* subshell on first preredir */
break;
setsigdefaults(FALSE);
qredir(n->u[0].p);
if (!haspreredir(n->u[1].p))
doredirs(); /* no more preredirs, empty queue */
walk(n->u[1].p, FALSE);
rc_exit(getstatus());
/* NOTREACHED */
} else if (n->u[0].p->type == nAssign) {
if (isallpre(n->u[1].p)) {
walk(n->u[0].p, TRUE);
WALK(n->u[1].p, parent);
} else {
Estack e;
Edata var;
v = glom(n->u[0].p->u[0].p);
assign(v, glob(glom(n->u[0].p->u[1].p)), TRUE);
var.name = v->w;
except(eVarstack, var, &e);
walk(n->u[1].p, parent);
varrm(v->w, TRUE);
unexcept(); /* eVarstack */
}
} else
panic("unexpected node in preredir section of walk");
break;
}
case nBrace:
if (n->u[1].p == NULL) {
WALK(n->u[0].p, parent);
} else if (dofork(parent)) {
setsigdefaults(FALSE);
walk(n->u[1].p, TRUE); /* Do redirections */
redirq = NULL; /* Reset redirection queue */
walk(n->u[0].p, FALSE); /* Do commands */
rc_exit(getstatus());
/* NOTREACHED */
}
break;
case nEpilog:
qredir(n->u[0].p);
if (n->u[1].p != NULL) {
WALK(n->u[1].p, parent); /* Do more redirections. */
} else {
doredirs(); /* Okay, we hit the bottom. */
}
break;
case nNmpipe:
rc_error("named pipes cannot be executed as commands");
/* NOTREACHED */
default:
panic("unknown node in walk");
/* NOTREACHED */
}
return istrue();
}
