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Remove excessive memory allocation from dcb_printf

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The function allocated a constant-sized chunk of memory for all messages
which was excessive as well as potentially dangerous when used with large
strings.
This commit is contained in:
Markus Mäkelä
2019-03-28 12:39:06 +02:00
parent c4b82b7d83
commit 0fa7ad8580
1 changed files with 13 additions and 9 deletions
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22
server/core/dcb.cc
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@ -1767,19 +1767,23 @@ const char* gw_dcb_state2string(dcb_state_t state)
*/ */
void dcb_printf(DCB* dcb, const char* fmt, ...) void dcb_printf(DCB* dcb, const char* fmt, ...)
{ {
GWBUF* buf;
va_list args; va_list args;
if ((buf = gwbuf_alloc(10240)) == NULL)
{
return;
}
va_start(args, fmt); va_start(args, fmt);
vsnprintf((char*)GWBUF_DATA(buf), 10240, fmt, args); int n = vsnprintf(nullptr, 0, fmt, args);
va_end(args); va_end(args);
buf->end = (void*)((char*)GWBUF_DATA(buf) + strlen((char*)GWBUF_DATA(buf))); GWBUF* buf = gwbuf_alloc(n + 1);
dcb->func.write(dcb, buf);
if (buf)
{
va_start(args, fmt);
vsnprintf((char*)GWBUF_DATA(buf), n + 1, fmt, args);
va_end(args);
// Remove the trailing null character
GWBUF_RTRIM(buf, 1);
dcb->func.write(dcb, buf);
}
} }
/** /**