awk: do not allow $(-1)

[oweals/busybox.git] / editors / awk.c

diff --git a/editors/awk.c b/editors/awk.c
index aa927db1a3302af2b350d0a31f96d5599359388c..bafc9ba1d382b6bbb2651469aefd12b1161625b5 100644 (file)
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -6,13 +6,11 @@
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
-
 //config:config AWK
 //config:      bool "awk (22 kb)"
 //config:      default y
 //config:      help
-//config:      Awk is used as a pattern scanning and processing language. This is
-//config:      the BusyBox implementation of that programming language.
+//config:      Awk is used as a pattern scanning and processing language.
 //config:
 //config:config FEATURE_AWK_LIBM
 //config:      bool "Enable math functions (requires libm)"
@@ -71,7 +69,11 @@
 #endif
 
 
-#define OPTSTR_AWK \
+/* "+": stop on first non-option:
+ * $ awk 'BEGIN { for(i=1; i<ARGC; ++i) { print i ": " ARGV[i] }}' -argz
+ * 1: -argz
+ */
+#define OPTSTR_AWK "+" \
        "F:v:*f:*" \
        IF_FEATURE_AWK_GNU_EXTENSIONS("e:*") \
        "W:"
@@ -231,7 +233,7 @@ typedef struct tsplitter_s {
  */
 #define        TC_LENGTH       (1 << 20)
 #define        TC_GETLINE      (1 << 21)
-#define        TC_FUNCDECL     (1 << 22)               /* `function' `func' */
+#define        TC_FUNCDECL     (1 << 22)               /* 'function' 'func' */
 #define        TC_BEGIN        (1 << 23)
 #define        TC_END          (1 << 24)
 #define        TC_EOF          (1 << 25)
@@ -596,6 +598,7 @@ static const char EMSG_NOT_ARRAY[] ALIGN1 = "Not an array";
 static const char EMSG_POSSIBLE_ERROR[] ALIGN1 = "Possible syntax error";
 static const char EMSG_UNDEF_FUNC[] ALIGN1 = "Call to undefined function";
 static const char EMSG_NO_MATH[] ALIGN1 = "Math support is not compiled in";
+static const char EMSG_NEGATIVE_FIELD[] ALIGN1 = "Access to negative field";
 
 static void zero_out_var(var *vp)
 {
@@ -2512,6 +2515,32 @@ static var *evaluate(node *op, var *res)
                op1 = op->l.n;
                debug_printf_eval("opinfo:%08x opn:%08x\n", opinfo, opn);
 
+               /* "delete" is special:
+                * "delete array[var--]" must evaluate index expr only once,
+                * must not evaluate it in "execute inevitable things" part.
+                */
+               if (XC(opinfo & OPCLSMASK) == XC(OC_DELETE)) {
+                       uint32_t info = op1->info & OPCLSMASK;
+                       var *v;
+
+                       debug_printf_eval("DELETE\n");
+                       if (info == OC_VAR) {
+                               v = op1->l.v;
+                       } else if (info == OC_FNARG) {
+                               v = &fnargs[op1->l.aidx];
+                       } else {
+                               syntax_error(EMSG_NOT_ARRAY);
+                       }
+                       if (op1->r.n) { /* array ref? */
+                               const char *s;
+                               s = getvar_s(evaluate(op1->r.n, v1));
+                               hash_remove(iamarray(v), s);
+                       } else {
+                               clear_array(iamarray(v));
+                       }
+                       goto next;
+               }
+
                /* execute inevitable things */
                if (opinfo & OF_RES1)
                        L.v = evaluate(op1, v1);
@@ -2619,28 +2648,7 @@ static var *evaluate(node *op, var *res)
                        break;
                }
 
-               case XC( OC_DELETE ): {
-                       uint32_t info = op1->info & OPCLSMASK;
-                       var *v;
-
-                       if (info == OC_VAR) {
-                               v = op1->l.v;
-                       } else if (info == OC_FNARG) {
-                               v = &fnargs[op1->l.aidx];
-                       } else {
-                               syntax_error(EMSG_NOT_ARRAY);
-                       }
-
-                       if (op1->r.n) {
-                               const char *s;
-                               clrvar(L.v);
-                               s = getvar_s(evaluate(op1->r.n, v1));
-                               hash_remove(iamarray(v), s);
-                       } else {
-                               clear_array(iamarray(v));
-                       }
-                       break;
-               }
+               /* case XC( OC_DELETE ): - moved to happen before arg evaluation */
 
                case XC( OC_NEWSOURCE ):
                        g_progname = op->l.new_progname;
@@ -2664,12 +2672,14 @@ static var *evaluate(node *op, var *res)
                /* -- recursive node type -- */
 
                case XC( OC_VAR ):
+                       debug_printf_eval("VAR\n");
                        L.v = op->l.v;
                        if (L.v == intvar[NF])
                                split_f0();
                        goto v_cont;
 
                case XC( OC_FNARG ):
+                       debug_printf_eval("FNARG[%d]\n", op->l.aidx);
                        L.v = &fnargs[op->l.aidx];
  v_cont:
                        res = op->r.n ? findvar(iamarray(L.v), R.s) : L.v;
@@ -2940,6 +2950,8 @@ static var *evaluate(node *op, var *res)
 
                case XC( OC_FIELD ): {
                        int i = (int)getvar_i(R.v);
+                       if (i < 0)
+                               syntax_error(EMSG_NEGATIVE_FIELD);
                        if (i == 0) {
                                res = intvar[F0];
                        } else {
@@ -3033,7 +3045,8 @@ static var *evaluate(node *op, var *res)
 
                default:
                        syntax_error(EMSG_POSSIBLE_ERROR);
-               }
+               } /* switch */
+ next:
                if ((opinfo & OPCLSMASK) <= SHIFT_TIL_THIS)
                        op = op->a.n;
                if ((opinfo & OPCLSMASK) >= RECUR_FROM_THIS)
@@ -3139,7 +3152,7 @@ static rstream *next_input_file(void)
 }
 
 int awk_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int awk_main(int argc, char **argv)
+int awk_main(int argc UNUSED_PARAM, char **argv)
 {
        unsigned opt;
        char *opt_F;
@@ -3208,7 +3221,7 @@ int awk_main(int argc, char **argv)
        }
        opt = getopt32(argv, OPTSTR_AWK, &opt_F, &list_v, &list_f, IF_FEATURE_AWK_GNU_EXTENSIONS(&list_e,) NULL);
        argv += optind;
-       argc -= optind;
+       //argc -= optind;
        if (opt & OPT_W)
                bb_error_msg("warning: option -W is ignored");
        if (opt & OPT_F) {
@@ -3245,15 +3258,14 @@ int awk_main(int argc, char **argv)
                if (!*argv)
                        bb_show_usage();
                parse_program(*argv++);
-               argc--;
        }
 
        /* fill in ARGV array */
-       setvar_i(intvar[ARGC], argc + 1);
        setari_u(intvar[ARGV], 0, "awk");
        i = 0;
        while (*argv)
                setari_u(intvar[ARGV], ++i, *argv++);
+       setvar_i(intvar[ARGC], i + 1);
 
        evaluate(beginseq.first, &tv);
        if (!mainseq.first && !endseq.first)