/* parse a compound list
*
* The term compound-list is derived from the grammar in 3.10; it is
* equivalent to a sequence of lists, separated by <newline>s, that
* can be preceded or followed by an arbitrary number of <newline>s.
* ----------------------------------------------------------------------- */
union node *parse_compound_list(struct parser *p) {
union node *list;
union node **nptr;
tree_init(list, nptr);
/* skip arbitrary newlines */
while(parse_gettok(p, P_DEFAULT) & T_NL);
p->pushback++;
for(;;) {
/* try to parse a list */
*nptr = parse_list(p);
/* skip arbitrary newlines */
while(p->tok & T_NL) parse_gettok(p, P_DEFAULT);
p->pushback++;
/* no more lists */
if(*nptr == NULL)
break;
/* parse_list already returns a list, so we
must skip over it to get &lastnode->next */
while(*nptr)
tree_next(nptr);
}
return list;
}
/* 3.9.4.1 parse a grouping compound
*
* The format for grouping commands is a s follows:
*
* (compound-list) Execute compound-list in a subshell environment;
* Variable assignments and built-in commands that
* affect the environment shall not remain in effect
* after the list finishes.
*
* { compound-list;} Execute compound-list in the current process
* environment.
*
* ----------------------------------------------------------------------- */
union node *parse_grouping(struct parser *p) {
enum tok_flag tok;
union node **rptr;
union node *grouping;
union node *compound_list;
/* return NULL on empty compound */
grouping = NULL;
if(!(tok = parse_expect(p, P_DEFAULT, T_BEGIN|T_LP, NULL)))
return NULL;
/* parse compound content and create a
compound node if there are commands */
if((compound_list = parse_compound_list(p))) {
grouping = tree_newnode(tok == T_BEGIN ? N_CMDLIST : N_SUBSHELL);
grouping->ngrp.cmds = compound_list;
}
/* expect the appropriate ending token */
if(!parse_expect(p, P_DEFAULT, tok << 1, grouping))
return NULL;
if(grouping) {
tree_init(grouping->ngrp.rdir, rptr);
/* now any redirections may follow */
while(parse_gettok(p, P_DEFAULT) & T_REDIR)
tree_move(p->tree, rptr);
p->pushback++;
}
return grouping;
}
/* A list is a sequence of one or more AND-OR-lists separated by the
* operators
*
* ; &
*
* and optionally terminated by
*
* ; & <newline>
*
* ----------------------------------------------------------------------- */
union node *parse_list(struct parser *p) {
union node *list;
union node **nptr;
enum tok_flag tok;
/* keep looking for and-or lists */
tree_init(list, nptr);
while((*nptr = parse_and_or(p))) {
tok = parse_gettok(p, P_DEFAULT);
/* <newline> terminates the list and eats the token */
if(tok & T_NL)
return list;
/* there must be & or ; after the and-or list,
otherwise the list will be terminated */
if(!(tok & (T_SEMI | T_BGND))) {
p->pushback++;
break;
}
/* & causes async exec of preceding and-or list */
if(tok & T_BGND)
(*nptr)->nlist.bgnd = 1;
/* now check for another and-or list */
tree_next(nptr);
}
return list;
}
static int parse_expect(struct parser *p, int tempflags, int toks) {
int n, i, f;
if (parse_gettok(p, tempflags) & toks) return p->tok;
if (p->tok) {
for (i = 0, n = p->tok; n > 1; i++, n >>= 1);
fprintf(stderr, "unexpected token '%s', expecting '", tokens[i].name);
} else {
/* parse a compound- or a simple-command
* (pipeline and lists are done outside this)
* ----------------------------------------------------------------------- */
union node *parse_command(struct parser *p, int tempflags) {
enum tok_flag tok;
union node *command;
union node **rptr;
tok = parse_gettok(p, tempflags);
switch(tok) {
/* T_FOR begins an iteration statement */
case T_FOR:
command = parse_for(p);
break;
/* T_IF begins a case match statement */
case T_CASE:
command = parse_case(p);
break;
/* T_IF begins a conditional statement */
case T_IF:
command = parse_if(p);
break;
/* T_WHILE/T_UNTIL begin a for-loop statement */
case T_WHILE:
case T_UNTIL:
command = parse_loop(p);
break;
/* T_LP/T_BEGIN start a grouping compound */
case T_LP:
case T_BEGIN:
p->pushback++;
command = parse_grouping(p);
break;
/* handle simple commands */
case T_NAME:
case T_WORD:
case T_REDIR:
case T_ASSIGN:
p->pushback++;
command = parse_simple_command(p);
break;
/* it wasn't a compound command, return now */
default:
p->pushback++;
return NULL;
}
if(command) {
/* they all can have redirections, so parse these now */
rptr = &command->ncmd.rdir;
/*
* in the case of a simple command there are maybe already
* redirections in the list (because in a simple command they
* can appear between arguments), so skip to the end of the list.
*/
while(*rptr)
tree_next(rptr);
while(parse_gettok(p, P_DEFAULT) & T_REDIR)
tree_move(p->tree, rptr);
}
p->pushback++;
return command;
}
/* main loop, parse lines into trees and execute them
* ----------------------------------------------------------------------- */
void sh_loop(void) {
struct parser p;
union node *list;
stralloc cmd;
/* if we're in interactive mode some
additional stuff is to be initialized */
if(source->mode & SOURCE_IACTIVE)
history_load();
stralloc_init(&cmd);
parse_init(&p, P_DEFAULT);
while(!(parse_gettok(&p, P_DEFAULT) & T_EOF)) {
p.pushback++;
parse_lineno = source->line;
var_setvint("LINENO", parse_lineno, V_DEFAULT);
/* launch the parser to get a complete command */
if((list = parse_list(&p)))
{
struct eval e;
if(source->mode & SOURCE_IACTIVE)
{
tree_printlist(list, &cmd, NULL);
stralloc_catc(&cmd, '\n');
stralloc_nul(&cmd);
history_set(cmd.s);
cmd.s = NULL;
history_advance();
}
#ifdef DEBUG
/* debug_list(list, 0);
buffer_putnlflush(fd_err->w);*/
#endif /* DEBUG */
eval_push(&e, E_JCTL);
eval_tree(&e, list, E_ROOT|E_LIST);
sh->exitcode = eval_pop(&e);
stralloc_zero(&cmd);
tree_free(list);
} else if(!(p.tok & (T_NL | T_SEMI | T_BGND))) {
/* we have a parse error */
if(p.tok != T_EOF)
parse_error(&p, 0);
/* exit if not interactive */
if(!(source->mode & SOURCE_IACTIVE))
sh_exit(1);
/* ..otherwise discard the input buffer */
source_flush();
p.pushback = 0;
}
if(p.tok & (T_NL|T_SEMI|T_BGND))
p.pushback = 0;
/* reset prompt */
prompt_number = 0;
}
}
