awk: fix a SEGV

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 65 insertions, 9 deletions

diff --git a/editors/awk.c b/editors/awk.c
index 8117cab54..71abca215 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -25,6 +25,7 @@
  * to perform debug printfs to stderr: */
 #define debug_printf_walker(...)  do {} while (0)
 #define debug_printf_eval(...)  do {} while (0)
+#define debug_printf_parse(...)  do {} while (0)
 
 #ifndef debug_printf_walker
 # define debug_printf_walker(...) (fprintf(stderr, __VA_ARGS__))
@@ -32,6 +33,9 @@
 #ifndef debug_printf_eval
 # define debug_printf_eval(...) (fprintf(stderr, __VA_ARGS__))
 #endif
+#ifndef debug_printf_parse
+# define debug_printf_parse(...) (fprintf(stderr, __VA_ARGS__))
+#endif
 
 
 
@@ -435,13 +439,13 @@ struct globals {
         smallint nextrec;
         smallint nextfile;
         smallint is_f0_split;
+        smallint t_rollback;
 };
 struct globals2 {
         uint32_t t_info; /* often used */
         uint32_t t_tclass;
         char *t_string;
         int t_lineno;
-        int t_rollback;
 
         var *intvar[NUM_INTERNAL_VARS]; /* often used */
 
@@ -499,11 +503,11 @@ struct globals2 {
 #define nextrec      (G1.nextrec     )
 #define nextfile     (G1.nextfile    )
 #define is_f0_split  (G1.is_f0_split )
+#define t_rollback   (G1.t_rollback  )
 #define t_info       (G.t_info      )
 #define t_tclass     (G.t_tclass    )
 #define t_string     (G.t_string    )
 #define t_lineno     (G.t_lineno    )
-#define t_rollback   (G.t_rollback  )
 #define intvar       (G.intvar      )
 #define fsplitter    (G.fsplitter   )
 #define rsplitter    (G.rsplitter   )
@@ -1011,6 +1015,7 @@ static uint32_t next_token(uint32_t expected)
 
                 if (*p == '\0') {
                         tc = TC_EOF;
+                        debug_printf_parse("%s: token found: TC_EOF\n", __func__);
 
                 } else if (*p == '\"') {
                         /* it's a string */
@@ -1026,6 +1031,7 @@ static uint32_t next_token(uint32_t expected)
                         p++;
                         *s = '\0';
                         tc = TC_STRING;
+                        debug_printf_parse("%s: token found:'%s' TC_STRING\n", __func__, t_string);
 
                 } else if ((expected & TC_REGEXP) && *p == '/') {
                         /* it's regexp */
@@ -1048,6 +1054,7 @@ static uint32_t next_token(uint32_t expected)
                         p++;
                         *s = '\0';
                         tc = TC_REGEXP;
+                        debug_printf_parse("%s: token found:'%s' TC_REGEXP\n", __func__, t_string);
 
                 } else if (*p == '.' || isdigit(*p)) {
                         /* it's a number */
@@ -1057,6 +1064,7 @@ static uint32_t next_token(uint32_t expected)
                         if (*p == '.')
                                 syntax_error(EMSG_UNEXP_TOKEN);
                         tc = TC_NUMBER;
+                        debug_printf_parse("%s: token found:%f TC_NUMBER\n", __func__, t_double);
 
                 } else {
                         /* search for something known */
@@ -1079,6 +1087,7 @@ static uint32_t next_token(uint32_t expected)
                                 ) {
                                         /* then this is what we are looking for */
                                         t_info = *ti;
+                                        debug_printf_parse("%s: token found:'%.*s' t_info:%x\n", __func__, l, p, t_info);
                                         p += l;
                                         goto token_found;
                                 }
@@ -1102,14 +1111,17 @@ static uint32_t next_token(uint32_t expected)
                                 p = skip_spaces(p);
                         if (*p == '(') {
                                 tc = TC_FUNCTION;
+                                debug_printf_parse("%s: token found:'%s' TC_FUNCTION\n", __func__, t_string);
                         } else {
                                 if (*p == '[') {
                                         p++;
                                         tc = TC_ARRAY;
-                                }
+                                        debug_printf_parse("%s: token found:'%s' TC_ARRAY\n", __func__, t_string);
+                                } else
+                                        debug_printf_parse("%s: token found:'%s' TC_VARIABLE\n", __func__, t_string);
                         }
- token_found: ;
                 }
+ token_found:
                 g_pos = p;
 
                 /* skipping newlines in some cases */
@@ -1181,6 +1193,8 @@ static node *parse_expr(uint32_t iexp)
         uint32_t tc, xtc;
         var *v;
 
+        debug_printf_parse("%s(%x)\n", __func__, iexp);
+
         sn.info = PRIMASK;
         sn.r.n = glptr = NULL;
         xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP | iexp;
@@ -1189,12 +1203,14 @@ static node *parse_expr(uint32_t iexp)
 
                 if (glptr && (t_info == (OC_COMPARE | VV | P(39) | 2))) {
                         /* input redirection (<) attached to glptr node */
+                        debug_printf_parse("%s: input redir\n", __func__);
                         cn = glptr->l.n = new_node(OC_CONCAT | SS | P(37));
                         cn->a.n = glptr;
                         xtc = TC_OPERAND | TC_UOPPRE;
                         glptr = NULL;
 
                 } else if (tc & (TC_BINOP | TC_UOPPOST)) {
+                        debug_printf_parse("%s: TC_BINOP | TC_UOPPOST\n", __func__);
                         /* for binary and postfix-unary operators, jump back over
                          * previous operators with higher priority */
                         vn = cn;
@@ -1224,6 +1240,7 @@ static node *parse_expr(uint32_t iexp)
                         vn->a.n = cn;
 
                 } else {
+                        debug_printf_parse("%s: other\n", __func__);
                         /* for operands and prefix-unary operators, attach them
                          * to last node */
                         vn = cn;
@@ -1231,12 +1248,14 @@ static node *parse_expr(uint32_t iexp)
                         cn->a.n = vn;
                         xtc = TC_OPERAND | TC_UOPPRE | TC_REGEXP;
                         if (tc & (TC_OPERAND | TC_REGEXP)) {
+                                debug_printf_parse("%s: TC_OPERAND | TC_REGEXP\n", __func__);
                                 xtc = TC_UOPPRE | TC_UOPPOST | TC_BINOP | TC_OPERAND | iexp;
                                 /* one should be very careful with switch on tclass -
                                  * only simple tclasses should be used! */
                                 switch (tc) {
                                 case TC_VARIABLE:
                                 case TC_ARRAY:
+                                        debug_printf_parse("%s: TC_VARIABLE | TC_ARRAY\n", __func__);
                                         cn->info = OC_VAR;
                                         v = hash_search(ahash, t_string);
                                         if (v != NULL) {
@@ -1253,6 +1272,7 @@ static node *parse_expr(uint32_t iexp)
 
                                 case TC_NUMBER:
                                 case TC_STRING:
+                                        debug_printf_parse("%s: TC_NUMBER | TC_STRING\n", __func__);
                                         cn->info = OC_VAR;
                                         v = cn->l.v = xzalloc(sizeof(var));
                                         if (tc & TC_NUMBER)
@@ -1262,32 +1282,41 @@ static node *parse_expr(uint32_t iexp)
                                         break;
 
                                 case TC_REGEXP:
+                                        debug_printf_parse("%s: TC_REGEXP\n", __func__);
                                         mk_re_node(t_string, cn, xzalloc(sizeof(regex_t)*2));
                                         break;
 
                                 case TC_FUNCTION:
+                                        debug_printf_parse("%s: TC_FUNCTION\n", __func__);
                                         cn->info = OC_FUNC;
                                         cn->r.f = newfunc(t_string);
                                         cn->l.n = condition();
                                         break;
 
                                 case TC_SEQSTART:
+                                        debug_printf_parse("%s: TC_SEQSTART\n", __func__);
                                         cn = vn->r.n = parse_expr(TC_SEQTERM);
+                                        if (!cn)
+                                                syntax_error("Empty sequence");
                                         cn->a.n = vn;
                                         break;
 
                                 case TC_GETLINE:
+                                        debug_printf_parse("%s: TC_GETLINE\n", __func__);
                                         glptr = cn;
                                         xtc = TC_OPERAND | TC_UOPPRE | TC_BINOP | iexp;
                                         break;
 
                                 case TC_BUILTIN:
+                                        debug_printf_parse("%s: TC_BUILTIN\n", __func__);
                                         cn->l.n = condition();
                                         break;
                                 }
                         }
                 }
         }
+
+        debug_printf_parse("%s() returns %p\n", __func__, sn.r.n);
         return sn.r.n;
 }
 
@@ -1356,18 +1385,25 @@ static void chain_group(void)
         } while (c & TC_NEWLINE);
 
         if (c & TC_GRPSTART) {
+                debug_printf_parse("%s: TC_GRPSTART\n", __func__);
                 while (next_token(TC_GRPSEQ | TC_GRPTERM) != TC_GRPTERM) {
+                        debug_printf_parse("%s: !TC_GRPTERM\n", __func__);
                         if (t_tclass & TC_NEWLINE)
                                 continue;
                         rollback_token();
                         chain_group();
                 }
+                debug_printf_parse("%s: TC_GRPTERM\n", __func__);
         } else if (c & (TC_OPSEQ | TC_OPTERM)) {
+                debug_printf_parse("%s: TC_OPSEQ | TC_OPTERM\n", __func__);
                 rollback_token();
                 chain_expr(OC_EXEC | Vx);
-        } else {                                                /* TC_STATEMNT */
+        } else {
+                /* TC_STATEMNT */
+                debug_printf_parse("%s: TC_STATEMNT(?)\n", __func__);
                 switch (t_info & OPCLSMASK) {
                 case ST_IF:
+                        debug_printf_parse("%s: ST_IF\n", __func__);
                         n = chain_node(OC_BR | Vx);
                         n->l.n = condition();
                         chain_group();
@@ -1382,12 +1418,14 @@ static void chain_group(void)
                         break;
 
                 case ST_WHILE:
+                        debug_printf_parse("%s: ST_WHILE\n", __func__);
                         n2 = condition();
                         n = chain_loop(NULL);
                         n->l.n = n2;
                         break;
 
                 case ST_DO:
+                        debug_printf_parse("%s: ST_DO\n", __func__);
                         n2 = chain_node(OC_EXEC);
                         n = chain_loop(NULL);
                         n2->a.n = n->a.n;
@@ -1396,6 +1434,7 @@ static void chain_group(void)
                         break;
 
                 case ST_FOR:
+                        debug_printf_parse("%s: ST_FOR\n", __func__);
                         next_token(TC_SEQSTART);
                         n2 = parse_expr(TC_SEMICOL | TC_SEQTERM);
                         if (t_tclass & TC_SEQTERM) {    /* for-in */
@@ -1421,6 +1460,7 @@ static void chain_group(void)
 
                 case OC_PRINT:
                 case OC_PRINTF:
+                        debug_printf_parse("%s: OC_PRINT[F]\n", __func__);
                         n = chain_node(t_info);
                         n->l.n = parse_expr(TC_OPTERM | TC_OUTRDR | TC_GRPTERM);
                         if (t_tclass & TC_OUTRDR) {
@@ -1432,17 +1472,20 @@ static void chain_group(void)
                         break;
 
                 case OC_BREAK:
+                        debug_printf_parse("%s: OC_BREAK\n", __func__);
                         n = chain_node(OC_EXEC);
                         n->a.n = break_ptr;
                         break;
 
                 case OC_CONTINUE:
+                        debug_printf_parse("%s: OC_CONTINUE\n", __func__);
                         n = chain_node(OC_EXEC);
                         n->a.n = continue_ptr;
                         break;
 
                 /* delete, next, nextfile, return, exit */
                 default:
+                        debug_printf_parse("%s: default\n", __func__);
                         chain_expr(t_info);
                 }
         }
@@ -1460,19 +1503,24 @@ static void parse_program(char *p)
         while ((tclass = next_token(TC_EOF | TC_OPSEQ | TC_GRPSTART |
                         TC_OPTERM | TC_BEGIN | TC_END | TC_FUNCDECL)) != TC_EOF) {
 
-                if (tclass & TC_OPTERM)
+                if (tclass & TC_OPTERM) {
+                        debug_printf_parse("%s: TC_OPTERM\n", __func__);
                         continue;
+                }
 
                 seq = &mainseq;
                 if (tclass & TC_BEGIN) {
+                        debug_printf_parse("%s: TC_BEGIN\n", __func__);
                         seq = &beginseq;
                         chain_group();
 
                 } else if (tclass & TC_END) {
+                        debug_printf_parse("%s: TC_END\n", __func__);
                         seq = &endseq;
                         chain_group();
 
                 } else if (tclass & TC_FUNCDECL) {
+                        debug_printf_parse("%s: TC_FUNCDECL\n", __func__);
                         next_token(TC_FUNCTION);
                         g_pos++;
                         f = newfunc(t_string);
@@ -1490,22 +1538,27 @@ static void parse_program(char *p)
                         clear_array(ahash);
 
                 } else if (tclass & TC_OPSEQ) {
+                        debug_printf_parse("%s: TC_OPSEQ\n", __func__);
                         rollback_token();
                         cn = chain_node(OC_TEST);
                         cn->l.n = parse_expr(TC_OPTERM | TC_EOF | TC_GRPSTART);
                         if (t_tclass & TC_GRPSTART) {
+                                debug_printf_parse("%s: TC_GRPSTART\n", __func__);
                                 rollback_token();
                                 chain_group();
                         } else {
+                                debug_printf_parse("%s: !TC_GRPSTART\n", __func__);
                                 chain_node(OC_PRINT);
                         }
                         cn->r.n = mainseq.last;
 
                 } else /* if (tclass & TC_GRPSTART) */ {
+                        debug_printf_parse("%s: TC_GRPSTART(?)\n", __func__);
                         rollback_token();
                         chain_group();
                 }
         }
+        debug_printf_parse("%s: TC_EOF\n", __func__);
 }
 
 
@@ -3000,7 +3053,7 @@ int awk_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int awk_main(int argc, char **argv)
 {
         unsigned opt;
-        char *opt_F, *opt_W;
+        char *opt_F;
         llist_t *list_v = NULL;
         llist_t *list_f = NULL;
         int i, j;
@@ -3062,7 +3115,7 @@ int awk_main(int argc, char **argv)
                 }
         }
         opt_complementary = "v::f::"; /* -v and -f can occur multiple times */
-        opt = getopt32(argv, "F:v:f:W:", &opt_F, &list_v, &list_f, &opt_W);
+        opt = getopt32(argv, "F:v:f:W:", &opt_F, &list_v, &list_f, NULL);
         argv += optind;
         argc -= optind;
         if (opt & 0x1)
@@ -3096,7 +3149,7 @@ int awk_main(int argc, char **argv)
                 parse_program(*argv++);
         }
         if (opt & 0x8) // -W
-                bb_error_msg("warning: unrecognized option '-W %s' ignored", opt_W);
+                bb_error_msg("warning: option -W is ignored");
 
         /* fill in ARGV array */
         setvar_i(intvar[ARGC], argc);
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index 0afe9b9e7..5a323047d 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -202,4 +202,7 @@ end d
 " \
         "" ""
 
+testing "awk handles empty ()" \
+        "awk 'BEGIN {print()}' 2>&1" "awk: cmd. line:1: Empty sequence\n" "" ""
+
 exit $FAILCOUNT