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PG-223: Use memcpy and strlcpy to copy relations to counters. 

We redefine macro _snprintf to use memcpy, which performs better, we
also update call sites using this macro to add the null terminator
'\0' to the source string length, this way memcpy also correctly
copies the null terminator to the destination string.

We update _snprintf2 macro to use strlcpy, the reason we don't use
memcpy here is because in the place where this macro is called,
pgss_update_entry, only the maximum string length of REL_LEN=1000 is
specified as an upper bound to copy the relations string vector to the
destination counters, but since this data is string, we don't need to
copy 1k bytes for every entry, by using strlcpy the copy ends as soon as
the null terminator '\0' is found in the source string.
pull/97/head
Diego Fronza 2021-08-27 16:12:07 -04:00
parent a847ed95de
commit 549347025d
1 changed files with 10 additions and 16 deletions
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26
pg_stat_monitor.c
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@ -31,24 +31,14 @@ PG_MODULE_MAGIC;
#define PGUNSIXBIT(val) (((val) & 0x3F) + '0')
#define _snprintf(_str_dst, _str_src, _len, _max_len)\
do \
{ \
int i; \
for(i = 0; i < _len && i < _max_len; i++) \
{\
_str_dst[i] = _str_src[i]; \
}\
}while(0)
memcpy((void *)_str_dst, _str_src, _len < _max_len ? _len : _max_len)
#define _snprintf2(_str_dst, _str_src, _len1, _len2)\
do \
{ \
int i,j; \
int i; \
for(i = 0; i < _len1; i++) \
for(j = 0; j < _len2; j++) \
{ \
_str_dst[i][j] = _str_src[i][j]; \
} \
strlcpy((char *)_str_dst[i], _str_src[i], _len2); \
}while(0)
/*---- Initicalization Function Declarations ----*/
@ -1196,7 +1186,8 @@ pgss_update_entry(pgssEntry *entry,
if (reset)
memset(&entry->counters, 0, sizeof(Counters));
_snprintf(e->counters.info.comments, comments, comments_len, COMMENTS_LEN);
if (comments_len > 0)
_snprintf(e->counters.info.comments, comments, comments_len + 1, COMMENTS_LEN);
e->counters.state = kind;
if (kind == PGSS_PLAN)
{
@ -1248,8 +1239,11 @@ pgss_update_entry(pgssEntry *entry,
e->counters.resp_calls[index]++;
}
_snprintf(e->counters.planinfo.plan_text, plan_info->plan_text, plan_text_len, PLAN_TEXT_LEN);
_snprintf(e->counters.info.application_name, application_name, application_name_len, APPLICATIONNAME_LEN);
if (plan_text_len > 0)
_snprintf(e->counters.planinfo.plan_text, plan_info->plan_text, plan_text_len + 1, PLAN_TEXT_LEN);
if (application_name_len > 0)
_snprintf(e->counters.info.application_name, application_name, application_name_len + 1, APPLICATIONNAME_LEN);
e->counters.info.num_relations = num_relations;
_snprintf2(e->counters.info.relations, relations, num_relations, REL_LEN);