diff options
Diffstat (limited to 'db2/db/db_ret.c')
| -rw-r--r-- | db2/db/db_ret.c | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/db2/db/db_ret.c b/db2/db/db_ret.c index bcec308b95..65441aa45a 100644 --- a/db2/db/db_ret.c +++ b/db2/db/db_ret.c @@ -8,7 +8,7 @@ #include "config.h" #ifndef lint -static const char sccsid[] = "@(#)db_ret.c 10.8 (Sleepycat) 10/25/97"; +static const char sccsid[] = "@(#)db_ret.c 10.10 (Sleepycat) 11/28/97"; #endif /* not lint */ #ifndef NO_SYSTEM_INCLUDES @@ -116,35 +116,48 @@ __db_retcopy(dbt, data, len, memp, memsize, db_malloc) dbt->size = len; /* - * Allocate any necessary memory. + * Allocate memory to be owned by the application: DB_DBT_MALLOC. * - * XXX: Never allocate 0 bytes. + * !!! + * We always allocate memory, even if we're copying out 0 bytes. This + * guarantees consistency, i.e., the application can always free memory + * without concern as to how many bytes of the record were requested. + * + * XXX + * Never allocate 0 bytes, it's known to make malloc/realloc unhappy. + * + * Use the memory specified by the application: DB_DBT_USERMEM. + * + * !!! + * If the length we're going to copy is 0, the application-supplied + * memory pointer is allowed to be NULL. */ if (F_ISSET(dbt, DB_DBT_MALLOC)) { dbt->data = db_malloc == NULL ? - (void *)__db_malloc(len + 1) : + (void *)__db_malloc(len) : (void *)db_malloc(len + 1); if (dbt->data == NULL) return (ENOMEM); } else if (F_ISSET(dbt, DB_DBT_USERMEM)) { - if (dbt->ulen < len) + if (len != 0 && (dbt->data == NULL || dbt->ulen < len)) return (ENOMEM); } else if (memp == NULL || memsize == NULL) { return (EINVAL); } else { - if (*memsize == 0 || *memsize < len) { + if (len != 0 && (*memsize == 0 || *memsize < len)) { *memp = *memp == NULL ? - (void *)__db_malloc(len + 1) : - (void *)__db_realloc(*memp, len + 1); + (void *)__db_malloc(len) : + (void *)__db_realloc(*memp, len); if (*memp == NULL) { *memsize = 0; return (ENOMEM); } - *memsize = len + 1; + *memsize = len; } dbt->data = *memp; } - memcpy(dbt->data, data, len); + if (len != 0) + memcpy(dbt->data, data, len); return (0); } |