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Avoid malloc & memcpy in retro_serialize

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nfore 2023-04-01 12:11:35 -05:00
parent 18be318103
commit 661ecf42c3
3 changed files with 24 additions and 10 deletions
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20
libretro.cpp
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@ -2529,6 +2529,7 @@ size_t retro_serialize_size(void)
StateMem st; StateMem st;
st.data = NULL; st.data = NULL;
st.data_frontend = NULL;
st.loc = 0; st.loc = 0;
st.len = 0; st.len = 0;
st.malloced = 0; st.malloced = 0;
@ -2546,22 +2547,24 @@ bool retro_serialize(void *data, size_t size)
{ {
StateMem st; StateMem st;
bool ret = false; bool ret = false;
uint8_t *_dat = (uint8_t*)malloc(size);
if (!_dat) st.data_frontend = (uint8_t *)data;
return false; st.data = st.data_frontend;
/* Mednafen can realloc the buffer so we need to ensure this is safe. */
st.data = _dat;
st.loc = 0; st.loc = 0;
st.len = 0; st.len = 0;
st.malloced = size; st.malloced = size;
st.initial_malloc = 0; st.initial_malloc = 0;
/* MDFNSS_SaveSM will malloc separate memory for st.data to complete
* the save if the passed-in size is too small */
ret = MDFNSS_SaveSM(&st, 0, 0, NULL, NULL, NULL); ret = MDFNSS_SaveSM(&st, 0, 0, NULL, NULL, NULL);
memcpy(data, st.data, size); if (st.data != st.data_frontend)
{
log_cb(RETRO_LOG_WARN, "Save state size has increased\n");
free(st.data); free(st.data);
ret = false;
}
return ret; return ret;
} }
@ -2570,7 +2573,8 @@ bool retro_unserialize(const void *data, size_t size)
{ {
StateMem st; StateMem st;
st.data = (uint8_t*)data; st.data_frontend = (uint8_t *)data;
st.data = st.data_frontend;
st.loc = 0; st.loc = 0;
st.len = size; st.len = size;
st.malloced = 0; st.malloced = 0;

9
mednafen/state.c
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@ -54,7 +54,16 @@ static int32_t smem_write(StateMem *st, void *buffer, uint32_t len)
while(newsize < (len + st->loc)) while(newsize < (len + st->loc))
newsize *= 2; newsize *= 2;
/* Don't realloc data_frontend memory */
if (st->data == st->data_frontend && st->data != NULL )
{
st->data = (uint8_t *)malloc(newsize);
memcpy(st->data, st->data_frontend, st->malloced);
}
else
st->data = (uint8_t *)realloc(st->data, newsize); st->data = (uint8_t *)realloc(st->data, newsize);
st->malloced = newsize; st->malloced = newsize;
} }
memcpy(st->data + st->loc, buffer, len); memcpy(st->data + st->loc, buffer, len);

1
mednafen/state.h
View File

@ -17,6 +17,7 @@
typedef struct typedef struct
{ {
uint8_t *data; uint8_t *data;
uint8_t *data_frontend; /* never realloc'd */
uint32_t loc; uint32_t loc;
uint32_t len; uint32_t len;
uint32_t malloced; uint32_t malloced;