From 09ac603c36d1c865df68e5abd9dab04bd0fa5e48 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 2 Oct 2012 17:31:40 -0400 Subject: [PATCH] Work around unportable behavior of malloc(0) and realloc(NULL, 0). 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. --- contrib/oid2name/oid2name.c | 38 +++++++++++++++++++++--------- contrib/pg_upgrade/util.c | 24 ++++++++++++------- contrib/pgbench/pgbench.c | 6 +++++ src/backend/utils/misc/guc.c | 6 +++++ src/bin/initdb/initdb.c | 3 +++ src/bin/pg_basebackup/streamutil.c | 3 +++ src/bin/pg_ctl/pg_ctl.c | 3 +++ src/bin/pg_dump/dumpmem.c | 6 +++++ src/bin/psql/common.c | 3 +++ src/bin/scripts/common.c | 3 +++ src/port/dirmod.c | 12 ++++++++-- 11 files changed, 85 insertions(+), 22 deletions(-) diff --git a/contrib/oid2name/oid2name.c b/contrib/oid2name/oid2name.c index 17d4d80fc9..a666731e72 100644 --- a/contrib/oid2name/oid2name.c +++ b/contrib/oid2name/oid2name.c @@ -51,6 +51,7 @@ struct options static void help(const char *progname); void get_opts(int, char **, struct options *); void *pg_malloc(size_t size); +void *pg_realloc(void *ptr, size_t size); char *pg_strdup(const char *str); void add_one_elt(char *eltname, eary *eary); char *get_comma_elts(eary *eary); @@ -203,16 +204,37 @@ help(const char *progname) void * pg_malloc(size_t size) { - void *ptr = malloc(size); + void *ptr; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; + ptr = malloc(size); if (!ptr) { - fprintf(stderr, "out of memory"); + fprintf(stderr, "out of memory\n"); exit(1); } return ptr; } +void * +pg_realloc(void *ptr, size_t size) +{ + void *result; + + /* Avoid unportable behavior of realloc(NULL, 0) */ + if (ptr == NULL && size == 0) + size = 1; + result = realloc(ptr, size); + if (!result) + { + fprintf(stderr, "out of memory\n"); + exit(1); + } + return result; +} + char * pg_strdup(const char *str) { @@ -220,7 +242,7 @@ pg_strdup(const char *str) if (!result) { - fprintf(stderr, "out of memory"); + fprintf(stderr, "out of memory\n"); exit(1); } return result; @@ -242,14 +264,8 @@ add_one_elt(char *eltname, eary *eary) else if (eary->num >= eary->alloc) { eary ->alloc *= 2; - eary ->array = (char **) - realloc(eary->array, eary->alloc * sizeof(char *)); - - if (!eary->array) - { - fprintf(stderr, "out of memory"); - exit(1); - } + eary ->array = (char **) pg_realloc(eary->array, + eary->alloc * sizeof(char *)); } eary ->array[eary->num] = pg_strdup(eltname); diff --git a/contrib/pg_upgrade/util.c b/contrib/pg_upgrade/util.c index d879e762fa..1d4bc89f0b 100644 --- a/contrib/pg_upgrade/util.c +++ b/contrib/pg_upgrade/util.c @@ -192,33 +192,39 @@ get_user_info(char **user_name) void * -pg_malloc(size_t n) +pg_malloc(size_t size) { - void *p = malloc(n); + void *p; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; + p = malloc(size); if (p == NULL) pg_log(PG_FATAL, "%s: out of memory\n", os_info.progname); - return p; } void * -pg_realloc(void *ptr, size_t n) +pg_realloc(void *ptr, size_t size) { - void *p = realloc(ptr, n); + void *p; + /* Avoid unportable behavior of realloc(NULL, 0) */ + if (ptr == NULL && size == 0) + size = 1; + p = realloc(ptr, size); if (p == NULL) pg_log(PG_FATAL, "%s: out of memory\n", os_info.progname); - return p; } void -pg_free(void *p) +pg_free(void *ptr) { - if (p != NULL) - free(p); + if (ptr != NULL) + free(ptr); } diff --git a/contrib/pgbench/pgbench.c b/contrib/pgbench/pgbench.c index 509472262b..a669cf406b 100644 --- a/contrib/pgbench/pgbench.c +++ b/contrib/pgbench/pgbench.c @@ -299,6 +299,9 @@ pg_malloc(size_t size) { void *result; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; result = malloc(size); if (!result) { @@ -313,6 +316,9 @@ pg_realloc(void *ptr, size_t size) { void *result; + /* Avoid unportable behavior of realloc(NULL, 0) */ + if (ptr == NULL && size == 0) + size = 1; result = realloc(ptr, size); if (!result) { diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 48652b21ea..6b202e0425 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -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, diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c index 11ff554d79..c56f721e08 100644 --- a/src/bin/initdb/initdb.c +++ b/src/bin/initdb/initdb.c @@ -294,6 +294,9 @@ pg_malloc(size_t size) { void *result; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; result = malloc(size); if (!result) { diff --git a/src/bin/pg_basebackup/streamutil.c b/src/bin/pg_basebackup/streamutil.c index b6cc2a303e..22f4128180 100644 --- a/src/bin/pg_basebackup/streamutil.c +++ b/src/bin/pg_basebackup/streamutil.c @@ -54,6 +54,9 @@ pg_malloc0(size_t size) { void *result; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; result = malloc(size); if (!result) { diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c index 6d74a154ab..23c47f6275 100644 --- a/src/bin/pg_ctl/pg_ctl.c +++ b/src/bin/pg_ctl/pg_ctl.c @@ -233,6 +233,9 @@ pg_malloc(size_t size) { void *result; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; result = malloc(size); if (!result) { diff --git a/src/bin/pg_dump/dumpmem.c b/src/bin/pg_dump/dumpmem.c index 22637e26e4..08e82b269d 100644 --- a/src/bin/pg_dump/dumpmem.c +++ b/src/bin/pg_dump/dumpmem.c @@ -42,6 +42,9 @@ pg_malloc(size_t size) { void *tmp; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; tmp = malloc(size); if (!tmp) exit_horribly(NULL, "out of memory\n"); @@ -63,6 +66,9 @@ pg_realloc(void *ptr, size_t size) { void *tmp; + /* Avoid unportable behavior of realloc(NULL, 0) */ + if (ptr == NULL && size == 0) + size = 1; tmp = realloc(ptr, size); if (!tmp) exit_horribly(NULL, "out of memory\n"); diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c index 1cb30088c4..179c162279 100644 --- a/src/bin/psql/common.c +++ b/src/bin/psql/common.c @@ -60,6 +60,9 @@ pg_malloc(size_t size) { void *tmp; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; tmp = malloc(size); if (!tmp) { diff --git a/src/bin/scripts/common.c b/src/bin/scripts/common.c index 4a7d02f777..7d8875d81c 100644 --- a/src/bin/scripts/common.c +++ b/src/bin/scripts/common.c @@ -304,6 +304,9 @@ pg_malloc(size_t size) { void *tmp; + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; tmp = malloc(size); if (!tmp) { diff --git a/src/port/dirmod.c b/src/port/dirmod.c index 22f5c591b0..514424f82e 100644 --- a/src/port/dirmod.c +++ b/src/port/dirmod.c @@ -70,7 +70,11 @@ fe_palloc(Size size) { void *res; - if ((res = malloc(size)) == NULL) + /* Avoid unportable behavior of malloc(0) */ + if (size == 0) + size = 1; + res = malloc(size); + if (res == NULL) { fprintf(stderr, _("out of memory\n")); exit(1); @@ -96,7 +100,11 @@ fe_repalloc(void *pointer, Size size) { void *res; - if ((res = realloc(pointer, size)) == NULL) + /* Avoid unportable behavior of realloc(NULL, 0) */ + if (pointer == NULL && size == 0) + size = 1; + res = realloc(pointer, size); + if (res == NULL) { fprintf(stderr, _("out of memory\n")); exit(1);