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Diffstat (limited to 'src/os/os_alloc.c')
| -rw-r--r-- | src/os/os_alloc.c | 464 |
1 files changed, 464 insertions, 0 deletions
diff --git a/src/os/os_alloc.c b/src/os/os_alloc.c new file mode 100644 index 00000000..fb7bf109 --- /dev/null +++ b/src/os/os_alloc.c @@ -0,0 +1,464 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1997, 2012 Oracle and/or its affiliates. All rights reserved. + * + * $Id$ + */ + +#include "db_config.h" + +#include "db_int.h" + +#ifdef DIAGNOSTIC +static void __os_guard __P((ENV *)); + +typedef union { + size_t size; + uintmax_t align; +} db_allocinfo_t; +#endif + +/* + * !!! + * Correct for systems that return NULL when you allocate 0 bytes of memory. + * There are several places in DB where we allocate the number of bytes held + * by the key/data item, and it can be 0. Correct here so that malloc never + * returns a NULL for that reason (which behavior is permitted by ANSI). We + * could make these calls macros on non-Alpha architectures (that's where we + * saw the problem), but it's probably not worth the autoconf complexity. + * + * !!! + * Correct for systems that don't set errno when malloc and friends fail. + * + * Out of memory. + * We wish to hold the whole sky, + * But we never will. + */ + +/* + * __os_umalloc -- + * Allocate memory to be used by the application. + * + * Use, in order of preference, the allocation function specified to the + * ENV handle, the allocation function specified as a replacement for + * the library malloc, or the library malloc(). + * + * PUBLIC: int __os_umalloc __P((ENV *, size_t, void *)); + */ +int +__os_umalloc(env, size, storep) + ENV *env; + size_t size; + void *storep; +{ + DB_ENV *dbenv; + int ret; + + dbenv = env == NULL ? NULL : env->dbenv; + + /* Never allocate 0 bytes -- some C libraries don't like it. */ + if (size == 0) + ++size; + + if (dbenv == NULL || dbenv->db_malloc == NULL) { + if (DB_GLOBAL(j_malloc) != NULL) + *(void **)storep = DB_GLOBAL(j_malloc)(size); + else + *(void **)storep = malloc(size); + if (*(void **)storep == NULL) { + /* + * Correct error return, see __os_malloc. + */ + if ((ret = __os_get_errno_ret_zero()) == 0) { + ret = ENOMEM; + __os_set_errno(ENOMEM); + } + __db_err(env, ret, DB_STR_A("0143", "malloc: %lu", + "%lu"), (u_long)size); + return (ret); + } + return (0); + } + + if ((*(void **)storep = dbenv->db_malloc(size)) == NULL) { + __db_errx(env, DB_STR("0144", + "user-specified malloc function returned NULL")); + return (ENOMEM); + } + + return (0); +} + +/* + * __os_urealloc -- + * Allocate memory to be used by the application. + * + * A realloc(3) counterpart to __os_umalloc's malloc(3). + * + * PUBLIC: int __os_urealloc __P((ENV *, size_t, void *)); + */ +int +__os_urealloc(env, size, storep) + ENV *env; + size_t size; + void *storep; +{ + DB_ENV *dbenv; + int ret; + void *ptr; + + dbenv = env == NULL ? NULL : env->dbenv; + ptr = *(void **)storep; + + /* Never allocate 0 bytes -- some C libraries don't like it. */ + if (size == 0) + ++size; + + if (dbenv == NULL || dbenv->db_realloc == NULL) { + if (ptr == NULL) + return (__os_umalloc(env, size, storep)); + + if (DB_GLOBAL(j_realloc) != NULL) + *(void **)storep = DB_GLOBAL(j_realloc)(ptr, size); + else + *(void **)storep = realloc(ptr, size); + if (*(void **)storep == NULL) { + /* + * Correct errno, see __os_realloc. + */ + if ((ret = __os_get_errno_ret_zero()) == 0) { + ret = ENOMEM; + __os_set_errno(ENOMEM); + } + __db_err(env, ret, DB_STR_A("0145", + "realloc: %lu", "%lu"), (u_long)size); + return (ret); + } + return (0); + } + + if ((*(void **)storep = dbenv->db_realloc(ptr, size)) == NULL) { + __db_errx(env, DB_STR("0146", + "User-specified realloc function returned NULL")); + return (ENOMEM); + } + + return (0); +} + +/* + * __os_ufree -- + * Free memory used by the application. + * + * A free(3) counterpart to __os_umalloc's malloc(3). + * + * PUBLIC: void __os_ufree __P((ENV *, void *)); + */ +void +__os_ufree(env, ptr) + ENV *env; + void *ptr; +{ + DB_ENV *dbenv; + + dbenv = env == NULL ? NULL : env->dbenv; + + if (dbenv != NULL && dbenv->db_free != NULL) + dbenv->db_free(ptr); + else if (DB_GLOBAL(j_free) != NULL) + DB_GLOBAL(j_free)(ptr); + else + free(ptr); +} + +/* + * __os_strdup -- + * The strdup(3) function for DB. + * + * PUBLIC: int __os_strdup __P((ENV *, const char *, void *)); + */ +int +__os_strdup(env, str, storep) + ENV *env; + const char *str; + void *storep; +{ + size_t size; + int ret; + void *p; + + *(void **)storep = NULL; + + size = strlen(str) + 1; + if ((ret = __os_malloc(env, size, &p)) != 0) + return (ret); + + memcpy(p, str, size); + + *(void **)storep = p; + return (0); +} + +/* + * __os_calloc -- + * The calloc(3) function for DB. + * + * PUBLIC: int __os_calloc __P((ENV *, size_t, size_t, void *)); + */ +int +__os_calloc(env, num, size, storep) + ENV *env; + size_t num, size; + void *storep; +{ + int ret; + + size *= num; + if ((ret = __os_malloc(env, size, storep)) != 0) + return (ret); + + memset(*(void **)storep, 0, size); + + return (0); +} + +/* + * __os_malloc -- + * The malloc(3) function for DB. + * + * PUBLIC: int __os_malloc __P((ENV *, size_t, void *)); + */ +int +__os_malloc(env, size, storep) + ENV *env; + size_t size; + void *storep; +{ + int ret; + void *p; + + *(void **)storep = NULL; + + /* Never allocate 0 bytes -- some C libraries don't like it. */ + if (size == 0) + ++size; + +#ifdef DIAGNOSTIC + /* Add room for size and a guard byte. */ + size += sizeof(db_allocinfo_t) + 1; +#endif + + if (DB_GLOBAL(j_malloc) != NULL) + p = DB_GLOBAL(j_malloc)(size); + else + p = malloc(size); + if (p == NULL) { + /* + * Some C libraries don't correctly set errno when malloc(3) + * fails. We'd like to 0 out errno before calling malloc, + * but it turns out that setting errno is quite expensive on + * Windows/NT in an MT environment. + */ + if ((ret = __os_get_errno_ret_zero()) == 0) { + ret = ENOMEM; + __os_set_errno(ENOMEM); + } + __db_err(env, ret, DB_STR_A("0147", "malloc: %lu", "%lu"), + (u_long)size); + return (ret); + } + +#ifdef DIAGNOSTIC + /* Overwrite memory. */ + memset(p, CLEAR_BYTE, size); + + /* + * Guard bytes: if #DIAGNOSTIC is defined, we allocate an additional + * byte after the memory and set it to a special value that we check + * for when the memory is free'd. + */ + ((u_int8_t *)p)[size - 1] = CLEAR_BYTE; + + ((db_allocinfo_t *)p)->size = size; + p = &((db_allocinfo_t *)p)[1]; +#endif + *(void **)storep = p; + + return (0); +} + +/* + * __os_realloc -- + * The realloc(3) function for DB. + * + * PUBLIC: int __os_realloc __P((ENV *, size_t, void *)); + */ +int +__os_realloc(env, size, storep) + ENV *env; + size_t size; + void *storep; +{ + int ret; + void *p, *ptr; + + ptr = *(void **)storep; + + /* Never allocate 0 bytes -- some C libraries don't like it. */ + if (size == 0) + ++size; + + /* If we haven't yet allocated anything yet, simply call malloc. */ + if (ptr == NULL) + return (__os_malloc(env, size, storep)); + +#ifdef DIAGNOSTIC + /* Add room for size and a guard byte. */ + size += sizeof(db_allocinfo_t) + 1; + + /* Back up to the real beginning */ + ptr = &((db_allocinfo_t *)ptr)[-1]; + + { + size_t s; + + s = ((db_allocinfo_t *)ptr)->size; + if (((u_int8_t *)ptr)[s - 1] != CLEAR_BYTE) + __os_guard(env); + } +#endif + + /* + * Don't overwrite the original pointer, there are places in DB we + * try to continue after realloc fails. + */ + if (DB_GLOBAL(j_realloc) != NULL) + p = DB_GLOBAL(j_realloc)(ptr, size); + else + p = realloc(ptr, size); + if (p == NULL) { + /* + * Some C libraries don't correctly set errno when malloc(3) + * fails. We'd like to 0 out errno before calling malloc, + * but it turns out that setting errno is quite expensive on + * Windows/NT in an MT environment. + */ + if ((ret = __os_get_errno_ret_zero()) == 0) { + ret = ENOMEM; + __os_set_errno(ENOMEM); + } + __db_err(env, ret, DB_STR_A("0148", "realloc: %lu", "%lu"), + (u_long)size); + return (ret); + } +#ifdef DIAGNOSTIC + ((u_int8_t *)p)[size - 1] = CLEAR_BYTE; /* Initialize guard byte. */ + + ((db_allocinfo_t *)p)->size = size; + p = &((db_allocinfo_t *)p)[1]; +#endif + + *(void **)storep = p; + + return (0); +} + +/* + * __os_free -- + * The free(3) function for DB. + * + * PUBLIC: void __os_free __P((ENV *, void *)); + */ +void +__os_free(env, ptr) + ENV *env; + void *ptr; +{ +#ifdef DIAGNOSTIC + size_t size; +#endif + + /* + * ANSI C requires free(NULL) work. Don't depend on the underlying + * library. + */ + if (ptr == NULL) + return; + +#ifdef DIAGNOSTIC + /* + * Check that the guard byte (one past the end of the memory) is + * still CLEAR_BYTE. + */ + ptr = &((db_allocinfo_t *)ptr)[-1]; + size = ((db_allocinfo_t *)ptr)->size; + if (((u_int8_t *)ptr)[size - 1] != CLEAR_BYTE) + __os_guard(env); + + /* Overwrite memory. */ + if (size != 0) + memset(ptr, CLEAR_BYTE, size); +#else + COMPQUIET(env, NULL); +#endif + + if (DB_GLOBAL(j_free) != NULL) + DB_GLOBAL(j_free)(ptr); + else + free(ptr); +} + +#ifdef DIAGNOSTIC +/* + * __os_guard -- + * Complain and abort. + */ +static void +__os_guard(env) + ENV *env; +{ + __db_errx(env, DB_STR("0149", + "Guard byte incorrect during free")); + __os_abort(env); + /* NOTREACHED */ +} +#endif + +/* + * __ua_memcpy -- + * Copy memory to memory without relying on any kind of alignment. + * + * There are places in DB that we have unaligned data, for example, + * when we've stored a structure in a log record as a DBT, and now + * we want to look at it. Unfortunately, if you have code like: + * + * struct a { + * int x; + * } *p; + * + * void *func_argument; + * int local; + * + * p = (struct a *)func_argument; + * memcpy(&local, p->x, sizeof(local)); + * + * compilers optimize to use inline instructions requiring alignment, + * and records in the log don't have any particular alignment. (This + * isn't a compiler bug, because it's a structure they're allowed to + * assume alignment.) + * + * Casting the memcpy arguments to (u_int8_t *) appears to work most + * of the time, but we've seen examples where it wasn't sufficient + * and there's nothing in ANSI C that requires that work. + * + * PUBLIC: void *__ua_memcpy __P((void *, const void *, size_t)); + */ +void * +__ua_memcpy(dst, src, len) + void *dst; + const void *src; + size_t len; +{ + return ((void *)memcpy(dst, src, len)); +} |