awk: Syntax error if delete isn't given an arg.

Unlike exit and return, delete strictly requires an arg, and derefs a
null pointer if executed without one.

Signed-off-by: Brian Foley <bpfoley@google.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 20 insertions, 10 deletions

diff --git a/editors/awk.c b/editors/awk.c
index f2b8b13eb..90edec82c 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -275,18 +275,21 @@ typedef struct tsplitter_s {
                    | TC_STRING | TC_NUMBER | TC_UOPPOST)
 #define TC_CONCAT2 (TC_OPERAND | TC_UOPPRE)
 
-#define OF_RES1    0x010000
-#define OF_RES2    0x020000
-#define OF_STR1    0x040000
-#define OF_STR2    0x080000
-#define OF_NUM1    0x100000
-#define OF_CHECKED 0x200000
+#define OF_RES1     0x010000
+#define OF_RES2     0x020000
+#define OF_STR1     0x040000
+#define OF_STR2     0x080000
+#define OF_NUM1     0x100000
+#define OF_CHECKED  0x200000
+#define OF_REQUIRED 0x400000
+
 
 /* combined operator flags */
 #define xx      0
 #define xV      OF_RES2
 #define xS      (OF_RES2 | OF_STR2)
 #define Vx      OF_RES1
+#define Rx      (OF_RES1 | OF_NUM1 | OF_REQUIRED)
 #define VV      (OF_RES1 | OF_RES2)
 #define Nx      (OF_RES1 | OF_NUM1)
 #define NV      (OF_RES1 | OF_NUM1 | OF_RES2)
@@ -425,7 +428,7 @@ static const uint32_t tokeninfo[] = {
         0,
         0, /* \n */
         ST_IF,        ST_DO,        ST_FOR,      OC_BREAK,
-        OC_CONTINUE,  OC_DELETE|Vx, OC_PRINT,
+        OC_CONTINUE,  OC_DELETE|Rx, OC_PRINT,
         OC_PRINTF,    OC_NEXT,      OC_NEXTFILE,
         OC_RETURN|Vx, OC_EXIT|Nx,
         ST_WHILE,
@@ -593,7 +596,7 @@ static const char EMSG_UNEXP_EOS[] ALIGN1 = "Unexpected end of string";
 static const char EMSG_UNEXP_TOKEN[] ALIGN1 = "Unexpected token";
 static const char EMSG_DIV_BY_ZERO[] ALIGN1 = "Division by zero";
 static const char EMSG_INV_FMT[] ALIGN1 = "Invalid format specifier";
-static const char EMSG_TOO_FEW_ARGS[] ALIGN1 = "Too few arguments for builtin";
+static const char EMSG_TOO_FEW_ARGS[] ALIGN1 = "Too few arguments";
 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";
@@ -1426,7 +1429,11 @@ static void chain_expr(uint32_t info)
         node *n;
 
         n = chain_node(info);
+
         n->l.n = parse_expr(TC_OPTERM | TC_GRPTERM);
+        if ((info & OF_REQUIRED) && !n->l.n)
+                syntax_error(EMSG_TOO_FEW_ARGS);
+
         if (t_tclass & TC_GRPTERM)
                 rollback_token();
 }
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index 9f353fc10..03fedf771 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -336,10 +336,13 @@ testing "awk continue" \
         'BEGIN { if (1) continue; else a = 1 }'
 
 testing "awk handles invalid for loop" \
-    "awk '{ for() }' 2>&1" "awk: cmd. line:1: Unexpected token\n" "" ""
+        "awk -e '{ for() }' 2>&1" "awk: cmd. line:1: Unexpected token\n" "" ""
 
 testing "awk handles colon not preceded by ternary" \
-    "awk 'foo:bar:' 2>&1" "awk: cmd. line:1: Unexpected token\n" "" ""
+        "awk -e foo:bar: 2>&1" "awk: cmd. line:1: Unexpected token\n" "" ""
+
+testing "awk errors on missing delete arg" \
+        "awk -e '{delete}' 2>&1" "awk: cmd. line:1: Too few arguments\n" "" ""
 
 # testing "description" "command" "result" "infile" "stdin"
 testing 'awk negative field access' \