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No errors in 'luaO_pushvfstring'

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Any call to 'va_start' must have a corresponding call to 'va_end';
so, functions called between them (luaO_pushvfstring in particular)
cannot raise errors.
This commit is contained in:
Roberto Ierusalimschy
2024-09-20 15:56:39 -03:00
parent 70d6975018
commit 20d42ccaae
5 changed files with 45 additions and 24 deletions
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37
lobject.c
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@@ -480,7 +480,7 @@ void luaO_tostring (lua_State *L, TValue *obj) {
#define BUFVFS cast_uint(LUA_IDSIZE + MAXNUMBER2STR + 95)
/*
** Buffer used by 'luaO_pushvfstring'. 'err' signals any error while
** Buffer used by 'luaO_pushvfstring'. 'err' signals an error while
** building result (memory error [1] or buffer overflow [2]).
*/
typedef struct BuffFS {
@@ -512,9 +512,14 @@ static void pushbuff (lua_State *L, void *ud) {
case 1:
luaD_throw(L, LUA_ERRMEM);
break;
case 2:
luaG_runerror(L, "buffer overflow");
break;
case 2: /* length overflow: Add "..." at the end of result */
if (buff->buffsize - buff->blen < 3)
strcpy(buff->b + buff->blen - 3, "..."); /* 'blen' must be > 3 */
else { /* there is enough space left for the "..." */
strcpy(buff->b + buff->blen, "...");
buff->blen += 3;
}
/* FALLTHROUGH */
default: { /* no errors */
TString *ts = luaS_newlstr(L, buff->b, buff->blen);
setsvalue2s(L, L->top.p, ts);
@@ -527,8 +532,10 @@ static void pushbuff (lua_State *L, void *ud) {
static const char *clearbuff (BuffFS *buff) {
lua_State *L = buff->L;
const char *res;
pushbuff(L, buff);
res = getstr(tsvalue(s2v(L->top.p - 1)));
if (luaD_rawrunprotected(L, pushbuff, buff) != LUA_OK) /* errors? */
res = NULL; /* error message is on the top of the stack */
else
res = getstr(tsvalue(s2v(L->top.p - 1)));
if (buff->b != buff->space) /* using dynamic buffer? */
luaM_freearray(L, buff->b, buff->buffsize); /* free it */
return res;
@@ -536,12 +543,14 @@ static const char *clearbuff (BuffFS *buff) {
static void addstr2buff (BuffFS *buff, const char *str, size_t slen) {
size_t left = buff->buffsize - buff->blen; /* space left in the buffer */
if (buff->err) /* do nothing else after an error */
return;
if (slen > buff->buffsize - buff->blen) {
/* new string doesn't fit into current buffer */
if (slen > left) { /* new string doesn't fit into current buffer? */
if (slen > ((MAX_SIZE/2) - buff->blen)) { /* overflow? */
buff->err = 2;
memcpy(buff->b + buff->blen, str, left); /* copy what it can */
buff->blen = buff->buffsize;
buff->err = 2; /* doesn't add anything else */
return;
}
else {
@@ -552,13 +561,13 @@ static void addstr2buff (BuffFS *buff, const char *str, size_t slen) {
: luaM_reallocvector(buff->L, buff->b, buff->buffsize, newsize,
char);
if (newb == NULL) { /* allocation error? */
buff->err = 1;
buff->err = 1; /* signal a memory error */
return;
}
if (buff->b == buff->space)
if (buff->b == buff->space) /* new buffer (not reallocated)? */
memcpy(newb, buff->b, buff->blen); /* copy previous content */
buff->b = newb;
buff->buffsize = newsize;
buff->b = newb; /* set new (larger) buffer... */
buff->buffsize = newsize; /* ...and its new size */
}
}
memcpy(buff->b + buff->blen, str, slen); /* copy new content */
@@ -651,6 +660,8 @@ const char *luaO_pushfstring (lua_State *L, const char *fmt, ...) {
va_start(argp, fmt);
msg = luaO_pushvfstring(L, fmt, argp);
va_end(argp);
if (msg == NULL) /* error? */
luaD_throw(L, LUA_ERRMEM);
return msg;
}