database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-07 00:36:50 +03:00
Code Activity

Work around unportable behavior of malloc(0) and realloc(NULL, 0).

Browse Source 
On some platforms these functions return NULL, rather than the more common
practice of returning a pointer to a zero-sized block of memory.  Hack our
various wrapper functions to hide the difference by substituting a size
request of 1.  This is probably not so important for the callers, who
should never touch the block anyway if they asked for size 0 --- but it's
important for the wrapper functions themselves, which mistakenly treated
the NULL result as an out-of-memory failure.  This broke at least pg_dump
for the case of no user-defined aggregates, as per report from
Matthew Carrington.

Back-patch to 9.2 to fix the pg_dump issue.  Given the lack of previous
complaints, it seems likely that there is no live bug in previous releases,
even though some of these functions were in place before that.
This commit is contained in:
Tom Lane
2012-10-02 17:31:40 -04:00
parent 2164f9a125
commit 09ac603c36
11 changed files with 85 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/backend/utils/misc/guc.c
View File

@ -3358,6 +3358,9 @@ guc_malloc(int elevel, size_t size)
{
void *data;
/* Avoid unportable behavior of malloc(0) */
if (size == 0)
size = 1;
data = malloc(size);
if (data == NULL)
ereport(elevel,
@ -3371,6 +3374,9 @@ guc_realloc(int elevel, void *old, size_t size)
{
void *data;
/* Avoid unportable behavior of realloc(NULL, 0) */
if (old == NULL && size == 0)
size = 1;
data = realloc(old, size);
if (data == NULL)
ereport(elevel,