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NetBSD/bin/ksh/syn.c

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/* $NetBSD: syn.c,v 1.2 1997/01/12 19:12:19 tls Exp $ */
/*
* shell parser (C version)
*/
#include "sh.h"
#include "c_test.h"
struct multiline_state {
int on; /* set in multiline commands (\n becomes ;) */
int start_token; /* token multiline is for (eg, FOR, {, etc.) */
int start_line; /* line multiline command started on */
};
static void yyparse ARGS((void));
static struct op *pipeline ARGS((int cf));
static struct op *andor ARGS((void));
static struct op *c_list ARGS((void));
static struct ioword *synio ARGS((int cf));
static void musthave ARGS((int c, int cf));
static struct op *nested ARGS((int type, int smark, int emark));
static struct op *get_command ARGS((int cf));
static struct op *dogroup ARGS((void));
static struct op *thenpart ARGS((void));
static struct op *elsepart ARGS((void));
static struct op *caselist ARGS((void));
static struct op *casepart ARGS((int endtok));
static struct op *function_body ARGS((char *name, int ksh_func));
static char ** wordlist ARGS((void));
static struct op *block ARGS((int type, struct op *t1, struct op *t2,
char **wp));
static struct op *newtp ARGS((int type));
static void syntaxerr ARGS((const char *what))
GCC_FUNC_ATTR(noreturn);
static void multiline_push ARGS((struct multiline_state *save, int tok));
static void multiline_pop ARGS((struct multiline_state *saved));
static int assign_command ARGS((char *s));
static int inalias ARGS((struct source *s));
#ifdef KSH
static int dbtestp_isa ARGS((Test_env *te, Test_meta meta));
static const char *dbtestp_getopnd ARGS((Test_env *te, Test_op op,
int do_eval));
static int dbtestp_eval ARGS((Test_env *te, Test_op op, const char *opnd1,
const char *opnd2, int do_eval));
static void dbtestp_error ARGS((Test_env *te, int offset, const char *msg));
#endif /* KSH */
static struct op *outtree; /* yyparse output */
static struct multiline_state multiline; /* \n changed to ; */
static int reject; /* token(cf) gets symbol again */
static int symbol; /* yylex value */
#define REJECT (reject = 1)
#define ACCEPT (reject = 0)
#define token(cf) \
((reject) ? (ACCEPT, symbol) : (symbol = yylex(cf)))
#define tpeek(cf) \
((reject) ? (symbol) : (REJECT, symbol = yylex(cf)))
static void
yyparse()
{
int c;
ACCEPT;
yynerrs = 0;
outtree = c_list();
c = tpeek(0);
if (c == 0 && !outtree)
outtree = newtp(TEOF);
else if (c != '\n' && c != 0)
syntaxerr((char *) 0);
}
static struct op *
pipeline(cf)
int cf;
{
register struct op *t, *p, *tl = NULL;
t = get_command(cf);
if (t != NULL) {
while (token(0) == '|') {
if ((p = get_command(CONTIN)) == NULL)
syntaxerr((char *) 0);
if (tl == NULL)
t = tl = block(TPIPE, t, p, NOWORDS);
else
tl = tl->right = block(TPIPE, tl->right, p, NOWORDS);
}
REJECT;
}
return (t);
}
static struct op *
andor()
{
register struct op *t, *p;
register int c;
t = pipeline(0);
if (t != NULL) {
while ((c = token(0)) == LOGAND || c == LOGOR) {
if ((p = pipeline(CONTIN)) == NULL)
syntaxerr((char *) 0);
t = block(c == LOGAND? TAND: TOR, t, p, NOWORDS);
}
REJECT;
}
return (t);
}
static struct op *
c_list()
{
register struct op *t, *p, *tl = NULL;
register int c;
t = andor();
if (t != NULL) {
/* Token has always been read/rejected at this point, so
* we don't worray about what flags to pass token()
*/
while ((c = token(0)) == ';' || c == '&' || c == COPROC ||
(c == '\n' && (multiline.on || inalias(source))))
{
if (c == '&' || c == COPROC) {
int type = c == '&' ? TASYNC : TCOPROC;
if (tl)
tl->right = block(type, tl->right,
NOBLOCK, NOWORDS);
else
t = block(type, t, NOBLOCK, NOWORDS);
}
if ((p = andor()) == NULL)
return (t);
if (tl == NULL)
t = tl = block(TLIST, t, p, NOWORDS);
else
tl = tl->right = block(TLIST, tl->right, p, NOWORDS);
}
REJECT;
}
return (t);
}
static struct ioword *
synio(cf)
int cf;
{
register struct ioword *iop;
int ishere;
if (tpeek(cf) != REDIR)
return NULL;
ACCEPT;
iop = yylval.iop;
ishere = (iop->flag&IOTYPE) == IOHERE;
musthave(LWORD, ishere ? HEREDELIM : 0);
if (ishere) {
iop->delim = yylval.cp;
if (*ident != 0) /* unquoted */
iop->flag |= IOEVAL;
if (herep >= &heres[HERES])
yyerror("too many <<'s\n");
*herep++ = iop;
} else
iop->name = yylval.cp;
return iop;
}
static void
musthave(c, cf)
int c, cf;
{
if ((token(cf)) != c)
syntaxerr((char *) 0);
}
static struct op *
nested(type, smark, emark)
int type, smark, emark;
{
register struct op *t;
struct multiline_state old_multiline;
multiline_push(&old_multiline, smark);
t = c_list();
musthave(emark, KEYWORD|ALIAS);
multiline_pop(&old_multiline);
return (block(type, t, NOBLOCK, NOWORDS));
}
static struct op *
get_command(cf)
int cf;
{
register struct op *t;
register int c, iopn = 0, syniocf;
struct ioword *iop, **iops;
XPtrV args, vars;
struct multiline_state old_multiline;
iops = (struct ioword **) alloc(sizeofN(struct ioword *, NUFILE+1),
ATEMP);
XPinit(args, 16);
XPinit(vars, 16);
/* Don't want to pass CONTIN if reading interactively as just hitting
* return would print PS2 instead of PS1.
*/
if (multiline.on || inalias(source))
cf = CONTIN;
syniocf = KEYWORD|ALIAS;
switch (c = token(cf|KEYWORD|ALIAS|VARASN)) {
default:
REJECT;
afree((void*) iops, ATEMP);
XPfree(args);
XPfree(vars);
return NULL; /* empty line */
case LWORD:
case REDIR:
REJECT;
syniocf &= ~(KEYWORD|ALIAS);
t = newtp(TCOM);
while (1) {
cf = (t->u.evalflags ? ARRAYVAR : 0)
| (XPsize(args) == 0 ? ALIAS|VARASN : CMDWORD);
switch (tpeek(cf)) {
case REDIR:
if (iopn >= NUFILE)
yyerror("too many redirections\n");
iops[iopn++] = synio(cf);
break;
case LWORD:
ACCEPT;
/* the iopn == 0 and XPsize(vars) == 0 are
* dubious but at&t ksh acts this way
*/
if (iopn == 0 && XPsize(vars) == 0
&& XPsize(args) == 0
&& assign_command(ident))
t->u.evalflags = DOVACHECK;
if ((XPsize(args) == 0 || Flag(FKEYWORD))
&& is_wdvarassign(yylval.cp))
XPput(vars, yylval.cp);
else
XPput(args, yylval.cp);
break;
case '(':
/* Check for "> foo (echo hi)", which at&t ksh
* allows (not POSIX, but not disallowed)
*/
afree(t, ATEMP);
if (XPsize(args) == 0 && XPsize(vars) == 0) {
ACCEPT;
goto Subshell;
}
/* Must be a function */
if (iopn != 0 || XPsize(args) != 1
|| XPsize(vars) != 0)
syntaxerr((char *) 0);
ACCEPT;
/*(*/
musthave(')', 0);
t = function_body(XPptrv(args)[0], FALSE);
goto Leave;
default:
goto Leave;
}
}
Leave:
break;
Subshell:
case '(':
t = nested(TPAREN, '(', ')');
break;
case '{': /*}*/
t = nested(TBRACE, '{', '}');
break;
#ifdef KSH
case MDPAREN:
{
static const char let_cmd[] = { CHAR, 'l', CHAR, 'e',
CHAR, 't', EOS };
syniocf &= ~(KEYWORD|ALIAS);
t = newtp(TCOM);
ACCEPT;
XPput(args, wdcopy(let_cmd, ATEMP));
musthave(LWORD,LETEXPR);
XPput(args, yylval.cp);
break;
}
#endif /* KSH */
#ifdef KSH
case DBRACKET: /* [[ .. ]] */
syniocf &= ~(KEYWORD|ALIAS);
t = newtp(TDBRACKET);
ACCEPT;
{
Test_env te;
te.flags = TEF_DBRACKET;
te.pos.av = &args;
te.isa = dbtestp_isa;
te.getopnd = dbtestp_getopnd;
te.eval = dbtestp_eval;
te.error = dbtestp_error;
test_parse(&te);
}
break;
#endif /* KSH */
case FOR:
case SELECT:
t = newtp((c == FOR) ? TFOR : TSELECT);
musthave(LWORD, ARRAYVAR);
if (!is_wdvarname(yylval.cp, TRUE))
yyerror("%s: bad identifier\n",
c == FOR ? "for" : "select");
t->str = str_save(ident, ATEMP);
multiline_push(&old_multiline, c);
t->vars = wordlist();
t->left = dogroup();
multiline_pop(&old_multiline);
break;
case WHILE:
case UNTIL:
multiline_push(&old_multiline, c);
t = newtp((c == WHILE) ? TWHILE : TUNTIL);
t->left = c_list();
t->right = dogroup();
multiline_pop(&old_multiline);
break;
case CASE:
t = newtp(TCASE);
musthave(LWORD, 0);
t->str = yylval.cp;
multiline_push(&old_multiline, c);
t->left = caselist();
multiline_pop(&old_multiline);
break;
case IF:
multiline_push(&old_multiline, c);
t = newtp(TIF);
t->left = c_list();
t->right = thenpart();
musthave(FI, KEYWORD|ALIAS);
multiline_pop(&old_multiline);
break;
case BANG:
syniocf &= ~(KEYWORD|ALIAS);
t = pipeline(0);
if (t == (struct op *) 0)
syntaxerr((char *) 0);
t = block(TBANG, NOBLOCK, t, NOWORDS);
break;
case TIME:
syniocf &= ~(KEYWORD|ALIAS);
t = pipeline(0);
t = block(TTIME, t, NOBLOCK, NOWORDS);
break;
case FUNCTION:
musthave(LWORD, 0);
t = function_body(yylval.cp, TRUE);
break;
}
while ((iop = synio(syniocf)) != NULL) {
if (iopn >= NUFILE)
yyerror("too many redirections\n");
iops[iopn++] = iop;
}
if (iopn == 0) {
afree((void*) iops, ATEMP);
t->ioact = NULL;
} else {
iops[iopn++] = NULL;
iops = (struct ioword **) aresize((void*) iops,
sizeofN(struct ioword *, iopn), ATEMP);
t->ioact = iops;
}
if (t->type == TCOM || t->type == TDBRACKET) {
XPput(args, NULL);
t->args = (char **) XPclose(args);
XPput(vars, NULL);
t->vars = (char **) XPclose(vars);
} else {
XPfree(args);
XPfree(vars);
}
return t;
}
static struct op *
dogroup()
{
register int c;
register struct op *list;
c = token(CONTIN|KEYWORD|ALIAS);
/* A {...} can be used instead of do...done for for/select loops
* but not for while/until loops - we don't need to check if it
* is a while loop because it would have been parsed as part of
* the conditional command list...
*/
if (c == DO)
c = DONE;
else if (c == '{')
c = '}';
else
syntaxerr((char *) 0);
list = c_list();
musthave(c, KEYWORD|ALIAS);
return list;
}
static struct op *
thenpart()
{
register struct op *t;
musthave(THEN, KEYWORD|ALIAS);
t = newtp(0);
t->left = c_list();
if (t->left == NULL)
syntaxerr((char *) 0);
t->right = elsepart();
return (t);
}
static struct op *
elsepart()
{
register struct op *t;
switch (token(KEYWORD|ALIAS|VARASN)) {
case ELSE:
if ((t = c_list()) == NULL)
syntaxerr((char *) 0);
return (t);
case ELIF:
t = newtp(TELIF);
t->left = c_list();
t->right = thenpart();
return (t);
default:
REJECT;
}
return NULL;
}
static struct op *
caselist()
{
register struct op *t, *tl;
int c;
c = token(CONTIN|KEYWORD|ALIAS);
/* A {...} can be used instead of in...esac for case statements */
if (c == IN)
c = ESAC;
else if (c == '{')
c = '}';
else
syntaxerr((char *) 0);
t = tl = NULL;
while ((tpeek(CONTIN|KEYWORD|ESACONLY)) != c) { /* no ALIAS here */
struct op *tc = casepart(c);
if (tl == NULL)
t = tl = tc, tl->right = NULL;
else
tl->right = tc, tl = tc;
}
musthave(c, KEYWORD|ALIAS);
return (t);
}
static struct op *
casepart(endtok)
int endtok;
{
register struct op *t;
register int c;
XPtrV ptns;
XPinit(ptns, 16);
t = newtp(TPAT);
c = token(CONTIN|KEYWORD); /* no ALIAS here */
if (c != '(')
REJECT;
do {
musthave(LWORD, 0);
XPput(ptns, yylval.cp);
} while ((c = token(0)) == '|');
REJECT;
XPput(ptns, NULL);
t->vars = (char **) XPclose(ptns);
musthave(')', 0);
t->left = c_list();
if ((tpeek(CONTIN|KEYWORD|ALIAS)) != endtok)
musthave(BREAK, CONTIN|KEYWORD|ALIAS);
return (t);
}
static struct op *
function_body(name, ksh_func)
char *name;
int ksh_func; /* function foo { ... } vs foo() { .. } */
{
XString xs;
char *xp, *p;
struct op *t;
int old_func_parse;
Xinit(xs, xp, 16, ATEMP);
for (p = name; ; ) {
if ((*p == EOS && Xlength(xs, xp) == 0)
|| (*p != EOS && *p != CHAR && *p != QCHAR
&& *p != OQUOTE && *p != CQUOTE))
{
p = snptreef((char *) 0, 32, "%S", name);
yyerror("%s: invalid function name\n", p);
}
Xcheck(xs, xp);
if (*p == EOS) {
Xput(xs, xp, '\0');
break;
} else if (*p == CHAR || *p == QCHAR) {
Xput(xs, xp, p[1]);
p += 2;
} else
p++; /* OQUOTE/CQUOTE */
}
t = newtp(TFUNCT);
t->str = Xclose(xs, xp);
t->u.ksh_func = ksh_func;
/* Note that POSIX allows only compound statements after foo(), sh and
* at&t ksh allow any command, go with the later since it shouldn't
* break anything. However, for function foo, at&t ksh only accepts
* an open-brace.
*/
if (ksh_func) {
musthave('{', CONTIN|KEYWORD|ALIAS); /* } */
REJECT;
}
old_func_parse = e->flags & EF_FUNC_PARSE;
e->flags |= EF_FUNC_PARSE;
if ((t->left = get_command(CONTIN)) == (struct op *) 0) {
/* create empty command so foo(): will work */
t->left = newtp(TCOM);
t->args = (char **) alloc(sizeof(char *), ATEMP);
t->args[0] = (char *) 0;
t->vars = (char **) alloc(sizeof(char *), ATEMP);
t->vars[0] = (char *) 0;
}
if (!old_func_parse)
e->flags &= ~EF_FUNC_PARSE;
return t;
}
static char **
wordlist()
{
register int c;
XPtrV args;
XPinit(args, 16);
if ((c = token(CONTIN|KEYWORD|ALIAS)) != IN) {
if (c != ';') /* non-POSIX, but at&t ksh accepts a ; here */
REJECT;
return NULL;
}
while ((c = token(0)) == LWORD)
XPput(args, yylval.cp);
if (c != '\n' && c != ';')
syntaxerr((char *) 0);
if (XPsize(args) == 0) {
XPfree(args);
return NULL;
} else {
XPput(args, NULL);
return (char **) XPclose(args);
}
}
/*
* supporting functions
*/
static struct op *
block(type, t1, t2, wp)
int type;
struct op *t1, *t2;
char **wp;
{
register struct op *t;
t = newtp(type);
t->left = t1;
t->right = t2;
t->vars = wp;
return (t);
}
const struct tokeninfo {
const char *name;
short val;
short reserved;
} tokentab[] = {
/* Reserved words */
{ "if", IF, TRUE },
{ "then", THEN, TRUE },
{ "else", ELSE, TRUE },
{ "elif", ELIF, TRUE },
{ "fi", FI, TRUE },
{ "case", CASE, TRUE },
{ "esac", ESAC, TRUE },
{ "for", FOR, TRUE },
#ifdef KSH
{ "select", SELECT, TRUE },
#endif /* KSH */
{ "while", WHILE, TRUE },
{ "until", UNTIL, TRUE },
{ "do", DO, TRUE },
{ "done", DONE, TRUE },
{ "in", IN, TRUE },
{ "function", FUNCTION, TRUE },
{ "time", TIME, TRUE },
{ "{", '{', TRUE },
{ "}", '}', TRUE },
{ "!", BANG, TRUE },
#ifdef KSH
{ "[[", DBRACKET, TRUE },
#endif /* KSH */
/* Lexical tokens (0[EOF], LWORD and REDIR handled specially) */
{ "&&", LOGAND, FALSE },
{ "||", LOGOR, FALSE },
{ ";;", BREAK, FALSE },
#ifdef KSH
{ "((", MDPAREN, FALSE },
{ "|&", COPROC, FALSE },
#endif /* KSH */
/* and some special cases... */
{ "newline", '\n', FALSE },
{ 0 }
};
void
initkeywords()
{
register struct tokeninfo const *tt;
register struct tbl *p;
tinit(&keywords, APERM, 32); /* must be 2^n (currently 20 keywords) */
for (tt = tokentab; tt->name; tt++) {
if (tt->reserved) {
p = tenter(&keywords, tt->name, hash(tt->name));
p->flag |= DEFINED|ISSET;
p->type = CKEYWD;
p->val.i = tt->val;
}
}
}
static void
syntaxerr(what)
const char *what;
{
char redir[6]; /* 2<<- is the longest redirection, I think */
const char *s;
struct tokeninfo const *tt;
int c;
if (!what)
what = "unexpected";
REJECT;
c = token(0);
Again:
switch (c) {
case 0:
if (multiline.on && multiline.start_token) {
multiline.on = FALSE; /* avoid infinate loops */
c = multiline.start_token;
source->errline = multiline.start_line;
what = "unmatched";
goto Again;
}
/* don't quote the EOF */
yyerror("syntax error: unexpected EOF\n");
/*NOTREACHED*/
case LWORD:
s = snptreef((char *) 0, 32, "%S", yylval.cp);
break;
case REDIR:
s = snptreef(redir, sizeof(redir), "%R", yylval.iop);
break;
default:
for (tt = tokentab; tt->name; tt++)
if (tt->val == c)
break;
if (tt->name)
s = tt->name;
else {
if (c > 0 && c < 256) {
redir[0] = c;
redir[1] = '\0';
} else
shf_snprintf(redir, sizeof(redir),
"?%d", c);
s = redir;
}
}
yyerror("syntax error: `%s' %s\n", s, what);
}
static void
multiline_push(save, tok)
struct multiline_state *save;
int tok;
{
*save = multiline;
multiline.on = TRUE;
multiline.start_token = tok;
multiline.start_line = source->line;
}
static void
multiline_pop(saved)
struct multiline_state *saved;
{
multiline = *saved;
}
static struct op *
newtp(type)
int type;
{
register struct op *t;
t = (struct op *) alloc(sizeof(*t), ATEMP);
t->type = type;
t->u.evalflags = 0;
t->args = t->vars = NULL;
t->ioact = NULL;
t->left = t->right = NULL;
t->str = NULL;
return (t);
}
struct op *
compile(s)
Source *s;
{
yynerrs = 0;
multiline.on = s->type == SSTRING;
multiline.start_token = 0;
multiline.start_line = 0;
herep = heres;
source = s;
yyparse();
return outtree;
}
/* This kludge exists to take care of sh/at&t ksh oddity in which
* the arguments of alias/export/readonly/typeset have no field
* splitting, file globbing, or (normal) tilde expansion done.
* at&t ksh seems to do something similar to this since
* $ touch a=a; typeset a=[ab]; echo "$a"
* a=[ab]
* $ x=typeset; $x a=[ab]; echo "$a"
* a=a
* $
*/
static int
assign_command(s)
char *s;
{
char c = *s;
if (Flag(FPOSIX) || !*s)
return 0;
return (c == 'a' && strcmp(s, "alias") == 0)
|| (c == 'e' && strcmp(s, "export") == 0)
|| (c == 'r' && strcmp(s, "readonly") == 0)
|| (c == 't' && strcmp(s, "typeset") == 0);
}
/* Check if we are in the middle of reading an alias */
static int
inalias(s)
struct source *s;
{
for (; s && s->type == SALIAS; s = s->next)
if (!(s->flags & SF_ALIASEND))
return 1;
return 0;
}
#ifdef KSH
/* Order important - indexed by Test_meta values
* Note that ||, &&, ( and ) can't appear in as unquoted strings
* in normal shell input, so these can be interpreted unambiguously
* in the evaluation pass.
*/
static const char dbtest_or[] = { CHAR, '|', CHAR, '|', EOS };
static const char dbtest_and[] = { CHAR, '&', CHAR, '&', EOS };
static const char dbtest_not[] = { CHAR, '!', EOS };
static const char dbtest_oparen[] = { CHAR, '(', EOS };
static const char dbtest_cparen[] = { CHAR, ')', EOS };
const char *const dbtest_tokens[] = {
dbtest_or, dbtest_and, dbtest_not,
dbtest_oparen, dbtest_cparen
};
const char db_close[] = { CHAR, ']', CHAR, ']', EOS };
const char db_lthan[] = { CHAR, '<', EOS };
const char db_gthan[] = { CHAR, '>', EOS };
/* Test if the current token is a whatever. Accepts the current token if
* it is. Returns 0 if it is not, non-zero if it is (in the case of
* TM_UNOP and TM_BINOP, the returned value is a Test_op).
*/
static int
dbtestp_isa(te, meta)
Test_env *te;
Test_meta meta;
{
int c = tpeek(ARRAYVAR | (meta == TM_BINOP ? 0 : CONTIN));
int uqword = 0;
char *save = (char *) 0;
int ret = 0;
/* unquoted word? */
uqword = c == LWORD && *ident;
if (meta == TM_OR)
ret = c == LOGOR;
else if (meta == TM_AND)
ret = c == LOGAND;
else if (meta == TM_NOT)
ret = uqword && strcmp(yylval.cp, dbtest_tokens[(int) TM_NOT]) == 0;
else if (meta == TM_OPAREN)
ret = c == '(' /*)*/;
else if (meta == TM_CPAREN)
ret = c == /*(*/ ')';
else if (meta == TM_UNOP || meta == TM_BINOP) {
if (meta == TM_BINOP && c == REDIR
&& (yylval.iop->flag == IOREAD
|| yylval.iop->flag == IOWRITE))
{
ret = 1;
save = wdcopy(yylval.iop->flag == IOREAD ?
db_lthan : db_gthan, ATEMP);
} else if (uqword && (ret = (int) test_isop(te, meta, ident)))
save = yylval.cp;
} else /* meta == TM_END */
ret = uqword && strcmp(yylval.cp, db_close) == 0;
if (ret) {
ACCEPT;
if (meta != TM_END) {
if (!save)
save = wdcopy(dbtest_tokens[(int) meta], ATEMP);
XPput(*te->pos.av, save);
}
}
return ret;
}
static const char *
dbtestp_getopnd(te, op, do_eval)
Test_env *te;
Test_op op;
int do_eval;
{
int c = tpeek(ARRAYVAR);
if (c != LWORD)
return (const char *) 0;
ACCEPT;
XPput(*te->pos.av, yylval.cp);
return null;
}
static int
dbtestp_eval(te, op, opnd1, opnd2, do_eval)
Test_env *te;
Test_op op;
const char *opnd1;
const char *opnd2;
int do_eval;
{
return 1;
}
static void
dbtestp_error(te, offset, msg)
Test_env *te;
int offset;
const char *msg;
{
te->flags |= TEF_ERROR;
if (offset < 0) {
REJECT;
/* Kludgy to say the least... */
symbol = LWORD;
yylval.cp = *(XPptrv(*te->pos.av) + XPsize(*te->pos.av)
+ offset);
}
syntaxerr(msg);
}
#endif /* KSH */
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