File 0002-awk-fix-precedence-of-relative-to.patch of Package busybox.43070
From c40fda7e0ac88d5197bfa0219fe5be450d86d81a Mon Sep 17 00:00:00 2001
From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Tue, 30 May 2023 16:42:18 +0200
Subject: [PATCH 2/7] awk: fix precedence of = relative to ==
Discovered while adding code to disallow assignments to non-lvalues
function old new delta
parse_expr 936 991 +55
.rodata 105243 105247 +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 59/0) Total: 59 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
(cherry picked from commit 0256e00a9d077588bd3a39f5a1ef7e2eaa2911e4)
---
editors/awk.c | 66 ++++++++++++++++++++++++++++++---------------
testsuite/awk.tests | 5 ++++
2 files changed, 50 insertions(+), 21 deletions(-)
diff --git a/editors/awk.c b/editors/awk.c
index e0ff068c1..40873519e 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -337,7 +337,9 @@ static void debug_parse_print_tc(uint32_t n)
#undef P
#undef PRIMASK
#undef PRIMASK2
-#define P(x) (x << 24)
+/* Smaller 'x' means _higher_ operator precedence */
+#define PRECEDENCE(x) (x << 24)
+#define P(x) PRECEDENCE(x)
#define PRIMASK 0x7F000000
#define PRIMASK2 0x7E000000
@@ -360,7 +362,7 @@ enum {
OC_MOVE = 0x1f00, OC_PGETLINE = 0x2000, OC_REGEXP = 0x2100,
OC_REPLACE = 0x2200, OC_RETURN = 0x2300, OC_SPRINTF = 0x2400,
OC_TERNARY = 0x2500, OC_UNARY = 0x2600, OC_VAR = 0x2700,
- OC_DONE = 0x2800,
+ OC_CONST = 0x2800, OC_DONE = 0x2900,
ST_IF = 0x3000, ST_DO = 0x3100, ST_FOR = 0x3200,
ST_WHILE = 0x3300
@@ -440,9 +442,9 @@ static const uint32_t tokeninfo[] ALIGN4 = {
#define TI_PREINC (OC_UNARY|xV|P(9)|'P')
#define TI_PREDEC (OC_UNARY|xV|P(9)|'M')
TI_PREINC, TI_PREDEC, OC_FIELD|xV|P(5),
- OC_COMPARE|VV|P(39)|5, OC_MOVE|VV|P(74), OC_REPLACE|NV|P(74)|'+', OC_REPLACE|NV|P(74)|'-',
- OC_REPLACE|NV|P(74)|'*', OC_REPLACE|NV|P(74)|'/', OC_REPLACE|NV|P(74)|'%', OC_REPLACE|NV|P(74)|'&',
- OC_BINARY|NV|P(29)|'+', OC_BINARY|NV|P(29)|'-', OC_REPLACE|NV|P(74)|'&', OC_BINARY|NV|P(15)|'&',
+ OC_COMPARE|VV|P(39)|5, OC_MOVE|VV|P(38), OC_REPLACE|NV|P(38)|'+', OC_REPLACE|NV|P(38)|'-',
+ OC_REPLACE|NV|P(38)|'*', OC_REPLACE|NV|P(38)|'/', OC_REPLACE|NV|P(38)|'%', OC_REPLACE|NV|P(38)|'&',
+ OC_BINARY|NV|P(29)|'+', OC_BINARY|NV|P(29)|'-', OC_REPLACE|NV|P(38)|'&', OC_BINARY|NV|P(15)|'&',
OC_BINARY|NV|P(25)|'/', OC_BINARY|NV|P(25)|'%', OC_BINARY|NV|P(15)|'&', OC_BINARY|NV|P(25)|'*',
OC_COMPARE|VV|P(39)|4, OC_COMPARE|VV|P(39)|3, OC_COMPARE|VV|P(39)|0, OC_COMPARE|VV|P(39)|1,
#define TI_LESS (OC_COMPARE|VV|P(39)|2)
@@ -1276,7 +1278,7 @@ static uint32_t next_token(uint32_t expected)
save_tclass = tc;
save_info = t_info;
tc = TC_BINOPX;
- t_info = OC_CONCAT | SS | P(35);
+ t_info = OC_CONCAT | SS | PRECEDENCE(35);
}
t_tclass = tc;
@@ -1336,9 +1338,8 @@ static node *parse_expr(uint32_t term_tc)
{
node sn;
node *cn = &sn;
- node *vn, *glptr;
+ node *glptr;
uint32_t tc, expected_tc;
- var *v;
debug_printf_parse("%s() term_tc(%x):", __func__, term_tc);
debug_parse_print_tc(term_tc);
@@ -1349,11 +1350,12 @@ static node *parse_expr(uint32_t term_tc)
expected_tc = TS_OPERAND | TS_UOPPRE | TC_REGEXP | term_tc;
while (!((tc = next_token(expected_tc)) & term_tc)) {
+ node *vn;
if (glptr && (t_info == TI_LESS)) {
/* 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 = glptr->l.n = new_node(OC_CONCAT | SS | PRECEDENCE(37));
cn->a.n = glptr;
expected_tc = TS_OPERAND | TS_UOPPRE;
glptr = NULL;
@@ -1365,24 +1367,42 @@ static node *parse_expr(uint32_t term_tc)
* previous operators with higher priority */
vn = cn;
while (((t_info & PRIMASK) > (vn->a.n->info & PRIMASK2))
- || ((t_info == vn->info) && t_info == TI_COLON)
+ || (t_info == vn->info && t_info == TI_COLON)
) {
vn = vn->a.n;
if (!vn->a.n) syntax_error(EMSG_UNEXP_TOKEN);
}
if (t_info == TI_TERNARY)
//TODO: why?
- t_info += P(6);
+ t_info += PRECEDENCE(6);
cn = vn->a.n->r.n = new_node(t_info);
cn->a.n = vn->a.n;
if (tc & TS_BINOP) {
cn->l.n = vn;
-//FIXME: this is the place to detect and reject assignments to non-lvalues.
-//Currently we allow "assignments" to consts and temporaries, nonsense like this:
-// awk 'BEGIN { "qwe" = 1 }'
-// awk 'BEGIN { 7 *= 7 }'
-// awk 'BEGIN { length("qwe") = 1 }'
-// awk 'BEGIN { (1+1) += 3 }'
+
+ /* Prevent:
+ * awk 'BEGIN { "qwe" = 1 }'
+ * awk 'BEGIN { 7 *= 7 }'
+ * awk 'BEGIN { length("qwe") = 1 }'
+ * awk 'BEGIN { (1+1) += 3 }'
+ */
+ /* Assignment? (including *= and friends) */
+ if (((t_info & OPCLSMASK) == OC_MOVE)
+ || ((t_info & OPCLSMASK) == OC_REPLACE)
+ ) {
+ debug_printf_parse("%s: MOVE/REPLACE vn->info:%08x\n", __func__, vn->info);
+ /* Left side is a (variable or array element)
+ * or function argument
+ * or $FIELD ?
+ */
+ if ((vn->info & OPCLSMASK) != OC_VAR
+ && (vn->info & OPCLSMASK) != OC_FNARG
+ && (vn->info & OPCLSMASK) != OC_FIELD
+ ) {
+ syntax_error(EMSG_UNEXP_TOKEN); /* no. bad */
+ }
+ }
+
expected_tc = TS_OPERAND | TS_UOPPRE | TC_REGEXP;
if (t_info == TI_PGETLINE) {
/* it's a pipe */
@@ -1418,6 +1438,8 @@ static node *parse_expr(uint32_t term_tc)
/* one should be very careful with switch on tclass -
* only simple tclasses should be used (TC_xyz, not TS_xyz) */
switch (tc) {
+ var *v;
+
case TC_VARIABLE:
case TC_ARRAY:
debug_printf_parse("%s: TC_VARIABLE | TC_ARRAY\n", __func__);
@@ -1438,14 +1460,14 @@ static node *parse_expr(uint32_t term_tc)
case TC_NUMBER:
case TC_STRING:
debug_printf_parse("%s: TC_NUMBER | TC_STRING\n", __func__);
- cn->info = OC_VAR;
+ cn->info = OC_CONST;
v = cn->l.v = xzalloc(sizeof(var));
- if (tc & TC_NUMBER)
+ if (tc & TC_NUMBER) {
setvar_i(v, t_double);
- else {
+ } else {
setvar_s(v, t_string);
- expected_tc &= ~TC_UOPPOST; /* "str"++ is not allowed */
}
+ expected_tc &= ~TC_UOPPOST; /* NUM++, "str"++ not allowed */
break;
case TC_REGEXP:
@@ -3088,6 +3110,8 @@ static var *evaluate(node *op, var *res)
/* -- recursive node type -- */
+ case XC( OC_CONST ):
+ debug_printf_eval("CONST ");
case XC( OC_VAR ):
debug_printf_eval("VAR\n");
L.v = op->l.v;
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index 495d77d70..b1697c137 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -530,4 +530,9 @@ testing 'awk assign while assign' \
│ trim/eff : 57.02%/26, 0.00% │ [cpu000:100%]
└────────────────────────────────────────────────────┘^C"
+testing "awk = has higher precedence than == (despite what gawk manpage claims)" \
+ "awk 'BEGIN { v=1; print 2==v; print 2==v=2; print v; print v=3==3; print v}'" \
+ '0\n1\n2\n1\n3\n' \
+ '' ''
+
exit $FAILCOUNT
--
2.52.0
