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authorDenys Vlasenko2018-12-25 18:37:52 +0100
committerDenys Vlasenko2018-12-25 18:37:52 +0100
commit2638454464b944f9c407326257851bab13c045ec (patch)
tree6afd3f8d336f4f22cc7bf87b40d896fadeff8879
parent5fa74b9efc538b55ec164ce3886eeea782016487 (diff)
downloadbusybox-2638454464b944f9c407326257851bab13c045ec.zip
busybox-2638454464b944f9c407326257851bab13c045ec.tar.gz
bc: add code to detect errors like "print 1 print 2"
function old new delta zbc_vm_process 831 925 +94 zbc_program_exec 3964 3976 +12 zdc_program_execStr 506 512 +6 zbc_lex_next 2161 2167 +6 zbc_program_assign 419 424 +5 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 5/0 up/down: 123/0) Total: 123 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--miscutils/bc.c49
1 files changed, 39 insertions, 10 deletions
diff --git a/miscutils/bc.c b/miscutils/bc.c
index 7c8edcf..8b44d44 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -711,6 +711,7 @@ dc_LEX_to_INST[] = { // starts at XC_LEX_OP_POWER // corresponding XC/DC_L
typedef struct BcLex {
const char *buf;
+ const char *lex_next_at; // last lex_next() was called at this string
size_t i;
size_t line;
size_t len;
@@ -2990,9 +2991,11 @@ static BC_STATUS zbc_lex_next(BcLex *l)
}
// here it's guaranteed that l->i is below l->len
}
+ l->lex_next_at = l->buf + l->i;
dbg_lex("next string to parse:'%.*s'",
- (int)(strchrnul(l->buf + l->i, '\n') - (l->buf + l->i)),
- l->buf + l->i);
+ (int)(strchrnul(l->lex_next_at, '\n') - l->lex_next_at),
+ l->lex_next_at
+ );
if (IS_BC) {
IF_BC(s = zbc_lex_token(l));
} else {
@@ -6756,13 +6759,38 @@ static BC_STATUS zbc_vm_process(const char *text)
dbg_lex("%s:%d G.prs.l.lex:%d, parsing...", __func__, __LINE__, G.prs.l.lex);
if (IS_BC) {
-// FIXME: "eating" of stmt delimiters is coded inconsistently
-// (sometimes zbc_parse_stmt() eats the delimiter, sometimes don't),
-// which causes bugs such as "print 1 print 2" erroneously accepted,
-// or "print 1 else 2" detecting parse error only after executing
-// "print 1" part.
- IF_BC(s = zbc_parse_stmt_or_funcdef(&G.prs));
+#if ENABLE_BC
+ s = zbc_parse_stmt_or_funcdef(&G.prs);
+ if (s) goto err;
+
+ // Check that next token is not bogus, and skip over
+ // stmt delimiter(s) - newlines and semicolons
+ s = 1; // s == 1 on first iteration only
+ for (;;) {
+ if (G.prs.l.lex == XC_LEX_EOF)
+ goto execute; // this goto avoids resetting 's' to zero
+ if (G.prs.l.lex != BC_LEX_SCOLON
+ && G.prs.l.lex != XC_LEX_NLINE
+ ) {
+ const char *err_at;
+ // Not newline and not semicolon
+ if (s == 0) // saw at least one NL/semicolon before it?
+ break; // yes, good
+//TODO: commolalize for other parse errors:
+ err_at = G.prs.l.lex_next_at ? G.prs.l.lex_next_at : "UNKNOWN";
+ bc_error_fmt("bad statement terminator at '%.*s'",
+ (int)(strchrnul(err_at, '\n') - err_at),
+ err_at
+ );
+ goto err;
+ }
+ // NL or semicolon: skip it, set s = 0, repeat
+ s = zbc_lex_next(&G.prs.l);
+ if (s) goto err;
+ }
+#endif
} else {
+#if ENABLE_DC
// Most of dc parsing assumes all whitespace,
// including '\n', is eaten.
while (G.prs.l.lex == XC_LEX_NLINE) {
@@ -6771,14 +6799,15 @@ static BC_STATUS zbc_vm_process(const char *text)
if (G.prs.l.lex == XC_LEX_EOF)
goto done;
}
- IF_DC(s = zdc_parse_expr(&G.prs));
+ s = zdc_parse_expr(&G.prs);
+#endif
}
if (s || G_interrupt) {
err:
bc_parse_reset(&G.prs); // includes bc_program_reset()
RETURN_STATUS(BC_STATUS_FAILURE);
}
-
+ IF_BC(execute:)
dbg_lex("%s:%d executing...", __func__, __LINE__);
s = zbc_program_exec();
if (s) {