[nasm:nasm-2.16.xx] BR 3392906: error out on bad syntax "db 1 2"
nasm-bot for H. Peter Anvin
hpa at zytor.com
Wed Oct 11 12:09:04 PDT 2023
Commit-ID: 73676357de6bf4028a9ccfb0bd443ed57935870c
Gitweb: http://repo.or.cz/w/nasm.git?a=commitdiff;h=73676357de6bf4028a9ccfb0bd443ed57935870c
Author: H. Peter Anvin <hpa at zytor.com>
AuthorDate: Wed, 11 Oct 2023 12:01:22 -0700
Committer: H. Peter Anvin <hpa at zytor.com>
CommitDate: Wed, 11 Oct 2023 12:06:58 -0700
BR 3392906: error out on bad syntax "db 1 2"
NASM would try to "eat the comma token" in db expressions, even for
cases where the token was not a comma. Fix that and error out
properly.
To give better error messages, track where in the input string a token
starts or ends. This information is only valid as long as the input
string is kept, but that is just fine for error messages during
parsing.
Reported-by: Peter Cordes <pcordes at gmail.com>
Signed-off-by: H. Peter Anvin <hpa at zytor.com>
---
asm/parser.c | 60 +++++++++++++++++++++++++++++++-------------
asm/stdscan.c | 24 +++++++++++++++---
include/nasm.h | 2 ++
test/baddb.asm | 5 ++++
travis/test/utf-error.stderr | 12 ++++-----
5 files changed, 76 insertions(+), 27 deletions(-)
diff --git a/asm/parser.c b/asm/parser.c
index 6b19ffac..26673196 100644
--- a/asm/parser.c
+++ b/asm/parser.c
@@ -1,6 +1,6 @@
/* ----------------------------------------------------------------------- *
*
- * Copyright 1996-2020 The NASM Authors - All Rights Reserved
+ * Copyright 1996-2023 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
@@ -55,6 +55,21 @@ static int end_expression_next(void);
static struct tokenval tokval;
+/*
+ * Human-readable description of a token, intended for error messages.
+ * The resulting string needs to be freed.
+ */
+static char *tokstr(const struct tokenval *tok)
+{
+ if (tok->t_type == TOKEN_EOS) {
+ return nasm_strdup("end of line");
+ } else if (tok->t_len) {
+ return nasm_asprintf("`%.*s'", tok->t_len, tok->t_start);
+ } else {
+ return nasm_strdup("invalid token");
+ }
+}
+
static void process_size_override(insn *result, operand *op)
{
if (tasm_compatible_mode) {
@@ -384,6 +399,7 @@ static int parse_eops(extop **result, bool critical, int elem)
/* End of string is obvious; ) ends a sub-expression list e.g. DUP */
for (i = tokval.t_type; i != TOKEN_EOS; i = stdscan(NULL, &tokval)) {
+ bool skip;
char endparen = ')'; /* Is a right paren the end of list? */
if (i == ')')
@@ -397,12 +413,9 @@ static int parse_eops(extop **result, bool critical, int elem)
}
sign = +1;
- /*
- * end_expression_next() here is to distinguish this from
- * a string used as part of an expression...
- */
if (i == TOKEN_QMARK) {
eop->type = EOT_DB_RESERVE;
+ skip = true;
} else if (do_subexpr && i == '(') {
extop *subexpr;
@@ -432,12 +445,13 @@ static int parse_eops(extop **result, bool critical, int elem)
/* We should have ended on a closing paren */
if (tokval.t_type != ')') {
- nasm_nonfatal("expected `)' after subexpression, got `%s'",
- i == TOKEN_EOS ?
- "end of line" : tokval.t_charptr);
+ char *tp = tokstr(&tokval);
+ nasm_nonfatal("expected `)' after subexpression, got %s", tp);
+ nasm_free(tp);
goto fail;
}
endparen = 0; /* This time the paren is not the end */
+ skip = true;
} else if (i == '%') {
/* %(expression_list) */
do_subexpr = true;
@@ -448,9 +462,14 @@ static int parse_eops(extop **result, bool critical, int elem)
do_subexpr = true;
continue;
} else if (i == TOKEN_STR && end_expression_next()) {
+ /*
+ * end_expression_next() is to distinguish this from
+ * a string used as part of an expression...
+ */
eop->type = EOT_DB_STRING;
eop->val.string.data = tokval.t_charptr;
eop->val.string.len = tokval.t_inttwo;
+ skip = true;
} else if (i == TOKEN_STRFUNC) {
bool parens = false;
const char *funcname = tokval.t_charptr;
@@ -463,8 +482,10 @@ static int parse_eops(extop **result, bool critical, int elem)
i = stdscan(NULL, &tokval);
}
if (i != TOKEN_STR) {
- nasm_nonfatal("%s must be followed by a string constant",
- funcname);
+ char *tp = tokstr(&tokval);
+ nasm_nonfatal("%s must be followed by a string constant, got %s",
+ funcname, tp);
+ nasm_free(tp);
eop->type = EOT_NOTHING;
} else {
eop->type = EOT_DB_STRING_FREE;
@@ -481,6 +502,7 @@ static int parse_eops(extop **result, bool critical, int elem)
if (i != ')')
nasm_nonfatal("unterminated %s function", funcname);
}
+ skip = i != ',';
} else if (i == '-' || i == '+') {
char *save = stdscan_get();
struct tokenval tmptok;
@@ -522,6 +544,7 @@ static int parse_eops(extop **result, bool critical, int elem)
}
if (!eop->val.string.len)
eop->type = EOT_NOTHING;
+ skip = true;
} else {
/* anything else, assume it is an expression */
expr *value;
@@ -548,6 +571,7 @@ static int parse_eops(extop **result, bool critical, int elem)
if (value_to_extop(value, eop, location.segment)) {
nasm_nonfatal("expression is not simple or relocatable");
}
+ skip = false;
}
if (eop->dup == 0 || eop->type == EOT_NOTHING) {
@@ -568,6 +592,11 @@ static int parse_eops(extop **result, bool critical, int elem)
oper_num++;
eop = NULL; /* Done with this operand */
+ if (skip) {
+ /* Consume the (last) token if that didn't happen yet */
+ i = stdscan(NULL, &tokval);
+ }
+
/*
* We're about to call stdscan(), which will eat the
* comma that we're currently sitting on between
@@ -577,13 +606,10 @@ static int parse_eops(extop **result, bool critical, int elem)
if (i == TOKEN_EOS || i == endparen) /* Already at end? */
break;
if (i != ',') {
- i = stdscan(NULL, &tokval); /* eat the comma or final paren */
- if (i == TOKEN_EOS || i == ')') /* got end of expression */
- break;
- if (i != ',') {
- nasm_nonfatal("comma expected after operand");
- goto fail;
- }
+ char *tp = tokstr(&tokval);
+ nasm_nonfatal("comma expected after operand, got %s", tp);
+ nasm_free(tp);
+ goto fail;
}
}
diff --git a/asm/stdscan.c b/asm/stdscan.c
index cbc0fc77..b8f0c850 100644
--- a/asm/stdscan.c
+++ b/asm/stdscan.c
@@ -1,6 +1,6 @@
/* ----------------------------------------------------------------------- *
*
- * Copyright 1996-2018 The NASM Authors - All Rights Reserved
+ * Copyright 1996-2023 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
@@ -122,19 +122,33 @@ static int stdscan_handle_brace(struct tokenval *tv)
return tv->t_type;
}
+static int stdscan_token(struct tokenval *tv);
+
int stdscan(void *private_data, struct tokenval *tv)
{
- const char *r;
+ int i;
(void)private_data; /* Don't warn that this parameter is unused */
nasm_zero(*tv);
stdscan_bufptr = nasm_skip_spaces(stdscan_bufptr);
+ tv->t_start = stdscan_bufptr;
+
if (!*stdscan_bufptr)
return tv->t_type = TOKEN_EOS;
- /* we have a token; either an id, a number or a char */
+ i = stdscan_token(tv);
+ tv->t_len = stdscan_bufptr - tv->t_start;
+
+ return i;
+}
+
+static int stdscan_token(struct tokenval *tv)
+{
+ const char *r;
+
+ /* we have a token; either an id, a number, operator or char */
if (nasm_isidstart(*stdscan_bufptr) ||
(*stdscan_bufptr == '$' && nasm_isidstart(stdscan_bufptr[1]))) {
/* now we've got an identifier */
@@ -341,6 +355,8 @@ int stdscan(void *private_data, struct tokenval *tv)
} else if (stdscan_bufptr[0] == '|' && stdscan_bufptr[1] == '|') {
stdscan_bufptr += 2;
return tv->t_type = TOKEN_DBL_OR;
- } else /* just an ordinary char */
+ } else {
+ /* just an ordinary char */
return tv->t_type = (uint8_t)(*stdscan_bufptr++);
+ }
}
diff --git a/include/nasm.h b/include/nasm.h
index 8b017f3e..45b07c9b 100644
--- a/include/nasm.h
+++ b/include/nasm.h
@@ -316,6 +316,8 @@ struct tokenval {
int64_t t_inttwo;
enum token_type t_type;
int8_t t_flag;
+ const char *t_start; /* Pointer to token in input buffer */
+ int t_len; /* Length of token in input buffer */
};
typedef int (*scanner)(void *private_data, struct tokenval *tv);
diff --git a/test/baddb.asm b/test/baddb.asm
new file mode 100644
index 00000000..1ff4fab4
--- /dev/null
+++ b/test/baddb.asm
@@ -0,0 +1,5 @@
+ ;; This should error
+ db 1 2
+
+ ;; This should work
+ db 1, 2
diff --git a/travis/test/utf-error.stderr b/travis/test/utf-error.stderr
index 5d2786da..f972605c 100644
--- a/travis/test/utf-error.stderr
+++ b/travis/test/utf-error.stderr
@@ -1,15 +1,15 @@
-./travis/test/utf.asm:63: error: __?utf16?__ must be followed by a string constant
-./travis/test/utf.asm:64: error: __?utf16?__ must be followed by a string constant
+./travis/test/utf.asm:63: error: __?utf16?__ must be followed by a string constant, got `33'
+./travis/test/utf.asm:64: error: __?utf16?__ must be followed by a string constant, got `,'
./travis/test/utf.asm:65: error: unterminated __?utf16?__ function
./travis/test/utf.asm:66: error: unterminated __?utf16?__ function
./travis/test/utf.asm:67: error: invalid input string to __?utf16?__
-./travis/test/utf.asm:69: error: __?utf16le?__ must be followed by a string constant
-./travis/test/utf.asm:70: error: __?utf16le?__ must be followed by a string constant
+./travis/test/utf.asm:69: error: __?utf16le?__ must be followed by a string constant, got `33'
+./travis/test/utf.asm:70: error: __?utf16le?__ must be followed by a string constant, got `,'
./travis/test/utf.asm:71: error: unterminated __?utf16le?__ function
./travis/test/utf.asm:72: error: unterminated __?utf16le?__ function
./travis/test/utf.asm:73: error: invalid input string to __?utf16le?__
-./travis/test/utf.asm:75: error: __?utf16be?__ must be followed by a string constant
-./travis/test/utf.asm:76: error: __?utf16be?__ must be followed by a string constant
+./travis/test/utf.asm:75: error: __?utf16be?__ must be followed by a string constant, got `33'
+./travis/test/utf.asm:76: error: __?utf16be?__ must be followed by a string constant, got `,'
./travis/test/utf.asm:77: error: unterminated __?utf16be?__ function
./travis/test/utf.asm:78: error: unterminated __?utf16be?__ function
./travis/test/utf.asm:79: error: invalid input string to __?utf16be?__
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