diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/malloc.c | 51 | ||||
| -rw-r--r-- | lib/malloc/dynarray-skeleton.c | 528 | ||||
| -rw-r--r-- | lib/malloc/dynarray.h | 177 | ||||
| -rw-r--r-- | lib/malloc/dynarray_at_failure.c | 40 | ||||
| -rw-r--r-- | lib/malloc/dynarray_emplace_enlarge.c | 77 | ||||
| -rw-r--r-- | lib/malloc/dynarray_finalize.c | 66 | ||||
| -rw-r--r-- | lib/malloc/dynarray_resize.c | 68 | ||||
| -rw-r--r-- | lib/malloc/dynarray_resize_clear.c | 39 | ||||
| -rw-r--r-- | lib/malloc/scratch_buffer.h | 135 | ||||
| -rw-r--r-- | lib/malloc/scratch_buffer_grow.c | 56 | ||||
| -rw-r--r-- | lib/malloc/scratch_buffer_grow_preserve.c | 67 | ||||
| -rw-r--r-- | lib/malloc/scratch_buffer_set_array_size.c | 64 | ||||
| -rw-r--r-- | lib/malloca.c | 112 | ||||
| -rw-r--r-- | lib/malloca.h | 132 |
14 files changed, 1612 insertions, 0 deletions
diff --git a/lib/malloc.c b/lib/malloc.c new file mode 100644 index 0000000..3ade35c --- /dev/null +++ b/lib/malloc.c @@ -0,0 +1,51 @@ +/* malloc() function that is glibc compatible. + + Copyright (C) 1997-1998, 2006-2007, 2009-2023 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* written by Jim Meyering and Bruno Haible */ + +#define _GL_USE_STDLIB_ALLOC 1 +#include <config.h> + +#include <stdlib.h> + +#include <errno.h> + +#include "xalloc-oversized.h" + +/* Allocate an N-byte block of memory from the heap, even if N is 0. */ + +void * +rpl_malloc (size_t n) +{ + if (n == 0) + n = 1; + + if (xalloc_oversized (n, 1)) + { + errno = ENOMEM; + return NULL; + } + + void *result = malloc (n); + +#if !HAVE_MALLOC_POSIX + if (result == NULL) + errno = ENOMEM; +#endif + + return result; +} diff --git a/lib/malloc/dynarray-skeleton.c b/lib/malloc/dynarray-skeleton.c new file mode 100644 index 0000000..580c278 --- /dev/null +++ b/lib/malloc/dynarray-skeleton.c @@ -0,0 +1,528 @@ +/* Type-safe arrays which grow dynamically. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +/* Pre-processor macros which act as parameters: + + DYNARRAY_STRUCT + The struct tag of dynamic array to be defined. + DYNARRAY_ELEMENT + The type name of the element type. Elements are copied + as if by memcpy, and can change address as the dynamic + array grows. + DYNARRAY_PREFIX + The prefix of the functions which are defined. + + The following parameters are optional: + + DYNARRAY_ELEMENT_FREE + DYNARRAY_ELEMENT_FREE (E) is evaluated to deallocate the + contents of elements. E is of type DYNARRAY_ELEMENT *. + DYNARRAY_ELEMENT_INIT + DYNARRAY_ELEMENT_INIT (E) is evaluated to initialize a new + element. E is of type DYNARRAY_ELEMENT *. + If DYNARRAY_ELEMENT_FREE but not DYNARRAY_ELEMENT_INIT is + defined, new elements are automatically zero-initialized. + Otherwise, new elements have undefined contents. + DYNARRAY_INITIAL_SIZE + The size of the statically allocated array (default: + at least 2, more elements if they fit into 128 bytes). + Must be a preprocessor constant. If DYNARRAY_INITIAL_SIZE is 0, + there is no statically allocated array at, and all non-empty + arrays are heap-allocated. + DYNARRAY_FINAL_TYPE + The name of the type which holds the final array. If not + defined, is PREFIX##finalize not provided. DYNARRAY_FINAL_TYPE + must be a struct type, with members of type DYNARRAY_ELEMENT and + size_t at the start (in this order). + + These macros are undefined after this header file has been + included. + + The following types are provided (their members are private to the + dynarray implementation): + + struct DYNARRAY_STRUCT + + The following functions are provided: + + void DYNARRAY_PREFIX##init (struct DYNARRAY_STRUCT *); + void DYNARRAY_PREFIX##free (struct DYNARRAY_STRUCT *); + bool DYNARRAY_PREFIX##has_failed (const struct DYNARRAY_STRUCT *); + void DYNARRAY_PREFIX##mark_failed (struct DYNARRAY_STRUCT *); + size_t DYNARRAY_PREFIX##size (const struct DYNARRAY_STRUCT *); + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##begin (const struct DYNARRAY_STRUCT *); + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##end (const struct DYNARRAY_STRUCT *); + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##at (struct DYNARRAY_STRUCT *, size_t); + void DYNARRAY_PREFIX##add (struct DYNARRAY_STRUCT *, DYNARRAY_ELEMENT); + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##emplace (struct DYNARRAY_STRUCT *); + bool DYNARRAY_PREFIX##resize (struct DYNARRAY_STRUCT *, size_t); + void DYNARRAY_PREFIX##remove_last (struct DYNARRAY_STRUCT *); + void DYNARRAY_PREFIX##clear (struct DYNARRAY_STRUCT *); + + The following functions are provided are provided if the + prerequisites are met: + + bool DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *, + DYNARRAY_FINAL_TYPE *); + (if DYNARRAY_FINAL_TYPE is defined) + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *, + size_t *); + (if DYNARRAY_FINAL_TYPE is not defined) +*/ + +#include <malloc/dynarray.h> + +#include <errno.h> +#include <stdlib.h> +#include <string.h> + +#ifndef DYNARRAY_STRUCT +# error "DYNARRAY_STRUCT must be defined" +#endif + +#ifndef DYNARRAY_ELEMENT +# error "DYNARRAY_ELEMENT must be defined" +#endif + +#ifndef DYNARRAY_PREFIX +# error "DYNARRAY_PREFIX must be defined" +#endif + +#ifdef DYNARRAY_INITIAL_SIZE +# if DYNARRAY_INITIAL_SIZE < 0 +# error "DYNARRAY_INITIAL_SIZE must be non-negative" +# endif +# if DYNARRAY_INITIAL_SIZE > 0 +# define DYNARRAY_HAVE_SCRATCH 1 +# else +# define DYNARRAY_HAVE_SCRATCH 0 +# endif +#else +/* Provide a reasonable default which limits the size of + DYNARRAY_STRUCT. */ +# define DYNARRAY_INITIAL_SIZE \ + (sizeof (DYNARRAY_ELEMENT) > 64 ? 2 : 128 / sizeof (DYNARRAY_ELEMENT)) +# define DYNARRAY_HAVE_SCRATCH 1 +#endif + +/* Public type definitions. */ + +/* All fields of this struct are private to the implementation. */ +struct DYNARRAY_STRUCT +{ + union + { + struct dynarray_header dynarray_abstract; + struct + { + /* These fields must match struct dynarray_header. */ + size_t used; + size_t allocated; + DYNARRAY_ELEMENT *array; + } dynarray_header; + } u; + +#if DYNARRAY_HAVE_SCRATCH + /* Initial inline allocation. */ + DYNARRAY_ELEMENT scratch[DYNARRAY_INITIAL_SIZE]; +#endif +}; + +/* Internal use only: Helper macros. */ + +/* Ensure macro-expansion of DYNARRAY_PREFIX. */ +#define DYNARRAY_CONCAT0(prefix, name) prefix##name +#define DYNARRAY_CONCAT1(prefix, name) DYNARRAY_CONCAT0(prefix, name) +#define DYNARRAY_NAME(name) DYNARRAY_CONCAT1(DYNARRAY_PREFIX, name) + +/* Use DYNARRAY_FREE instead of DYNARRAY_NAME (free), + so that Gnulib does not change 'free' to 'rpl_free'. */ +#define DYNARRAY_FREE DYNARRAY_CONCAT1 (DYNARRAY_NAME (f), ree) + +/* Address of the scratch buffer if any. */ +#if DYNARRAY_HAVE_SCRATCH +# define DYNARRAY_SCRATCH(list) (list)->scratch +#else +# define DYNARRAY_SCRATCH(list) NULL +#endif + +/* Internal use only: Helper functions. */ + +/* Internal function. Call DYNARRAY_ELEMENT_FREE with the array + elements. Name mangling needed due to the DYNARRAY_ELEMENT_FREE + macro expansion. */ +static inline void +DYNARRAY_NAME (free__elements__) (DYNARRAY_ELEMENT *__dynarray_array, + size_t __dynarray_used) +{ +#ifdef DYNARRAY_ELEMENT_FREE + for (size_t __dynarray_i = 0; __dynarray_i < __dynarray_used; ++__dynarray_i) + DYNARRAY_ELEMENT_FREE (&__dynarray_array[__dynarray_i]); +#endif /* DYNARRAY_ELEMENT_FREE */ +} + +/* Internal function. Free the non-scratch array allocation. */ +static inline void +DYNARRAY_NAME (free__array__) (struct DYNARRAY_STRUCT *list) +{ +#if DYNARRAY_HAVE_SCRATCH + if (list->u.dynarray_header.array != list->scratch) + free (list->u.dynarray_header.array); +#else + free (list->u.dynarray_header.array); +#endif +} + +/* Public functions. */ + +/* Initialize a dynamic array object. This must be called before any + use of the object. */ +__attribute_nonnull__ ((1)) +static void +DYNARRAY_NAME (init) (struct DYNARRAY_STRUCT *list) +{ + list->u.dynarray_header.used = 0; + list->u.dynarray_header.allocated = DYNARRAY_INITIAL_SIZE; + list->u.dynarray_header.array = DYNARRAY_SCRATCH (list); +} + +/* Deallocate the dynamic array and its elements. */ +__attribute_maybe_unused__ __attribute_nonnull__ ((1)) +static void +DYNARRAY_FREE (struct DYNARRAY_STRUCT *list) +{ + DYNARRAY_NAME (free__elements__) + (list->u.dynarray_header.array, list->u.dynarray_header.used); + DYNARRAY_NAME (free__array__) (list); + DYNARRAY_NAME (init) (list); +} + +/* Return true if the dynamic array is in an error state. */ +__attribute_nonnull__ ((1)) +static inline bool +DYNARRAY_NAME (has_failed) (const struct DYNARRAY_STRUCT *list) +{ + return list->u.dynarray_header.allocated == __dynarray_error_marker (); +} + +/* Mark the dynamic array as failed. All elements are deallocated as + a side effect. */ +__attribute_nonnull__ ((1)) +static void +DYNARRAY_NAME (mark_failed) (struct DYNARRAY_STRUCT *list) +{ + DYNARRAY_NAME (free__elements__) + (list->u.dynarray_header.array, list->u.dynarray_header.used); + DYNARRAY_NAME (free__array__) (list); + list->u.dynarray_header.array = DYNARRAY_SCRATCH (list); + list->u.dynarray_header.used = 0; + list->u.dynarray_header.allocated = __dynarray_error_marker (); +} + +/* Return the number of elements which have been added to the dynamic + array. */ +__attribute_nonnull__ ((1)) +static inline size_t +DYNARRAY_NAME (size) (const struct DYNARRAY_STRUCT *list) +{ + return list->u.dynarray_header.used; +} + +/* Return a pointer to the array element at INDEX. Terminate the + process if INDEX is out of bounds. */ +__attribute_nonnull__ ((1)) +static inline DYNARRAY_ELEMENT * +DYNARRAY_NAME (at) (struct DYNARRAY_STRUCT *list, size_t index) +{ + if (__glibc_unlikely (index >= DYNARRAY_NAME (size) (list))) + __libc_dynarray_at_failure (DYNARRAY_NAME (size) (list), index); + return list->u.dynarray_header.array + index; +} + +/* Return a pointer to the first array element, if any. For a + zero-length array, the pointer can be NULL even though the dynamic + array has not entered the failure state. */ +__attribute_nonnull__ ((1)) +static inline DYNARRAY_ELEMENT * +DYNARRAY_NAME (begin) (struct DYNARRAY_STRUCT *list) +{ + return list->u.dynarray_header.array; +} + +/* Return a pointer one element past the last array element. For a + zero-length array, the pointer can be NULL even though the dynamic + array has not entered the failure state. */ +__attribute_nonnull__ ((1)) +static inline DYNARRAY_ELEMENT * +DYNARRAY_NAME (end) (struct DYNARRAY_STRUCT *list) +{ + return list->u.dynarray_header.array + list->u.dynarray_header.used; +} + +/* Internal function. Slow path for the add function below. */ +static void +DYNARRAY_NAME (add__) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item) +{ + if (__glibc_unlikely + (!__libc_dynarray_emplace_enlarge (&list->u.dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)))) + { + DYNARRAY_NAME (mark_failed) (list); + return; + } + + /* Copy the new element and increase the array length. */ + list->u.dynarray_header.array[list->u.dynarray_header.used++] = item; +} + +/* Add ITEM at the end of the array, enlarging it by one element. + Mark *LIST as failed if the dynamic array allocation size cannot be + increased. */ +__attribute_nonnull__ ((1)) +static inline void +DYNARRAY_NAME (add) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item) +{ + /* Do nothing in case of previous error. */ + if (DYNARRAY_NAME (has_failed) (list)) + return; + + /* Enlarge the array if necessary. */ + if (__glibc_unlikely (list->u.dynarray_header.used + == list->u.dynarray_header.allocated)) + { + DYNARRAY_NAME (add__) (list, item); + return; + } + + /* Copy the new element and increase the array length. */ + list->u.dynarray_header.array[list->u.dynarray_header.used++] = item; +} + +/* Internal function. Building block for the emplace functions below. + Assumes space for one more element in *LIST. */ +static inline DYNARRAY_ELEMENT * +DYNARRAY_NAME (emplace__tail__) (struct DYNARRAY_STRUCT *list) +{ + DYNARRAY_ELEMENT *result + = &list->u.dynarray_header.array[list->u.dynarray_header.used]; + ++list->u.dynarray_header.used; +#if defined (DYNARRAY_ELEMENT_INIT) + DYNARRAY_ELEMENT_INIT (result); +#elif defined (DYNARRAY_ELEMENT_FREE) + memset (result, 0, sizeof (*result)); +#endif + return result; +} + +/* Internal function. Slow path for the emplace function below. */ +static DYNARRAY_ELEMENT * +DYNARRAY_NAME (emplace__) (struct DYNARRAY_STRUCT *list) +{ + if (__glibc_unlikely + (!__libc_dynarray_emplace_enlarge (&list->u.dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)))) + { + DYNARRAY_NAME (mark_failed) (list); + return NULL; + } + return DYNARRAY_NAME (emplace__tail__) (list); +} + +/* Allocate a place for a new element in *LIST and return a pointer to + it. The pointer can be NULL if the dynamic array cannot be + enlarged due to a memory allocation failure. */ +__attribute_maybe_unused__ __attribute_warn_unused_result__ +__attribute_nonnull__ ((1)) +static +/* Avoid inlining with the larger initialization code. */ +#if !(defined (DYNARRAY_ELEMENT_INIT) || defined (DYNARRAY_ELEMENT_FREE)) +inline +#endif +DYNARRAY_ELEMENT * +DYNARRAY_NAME (emplace) (struct DYNARRAY_STRUCT *list) +{ + /* Do nothing in case of previous error. */ + if (DYNARRAY_NAME (has_failed) (list)) + return NULL; + + /* Enlarge the array if necessary. */ + if (__glibc_unlikely (list->u.dynarray_header.used + == list->u.dynarray_header.allocated)) + return (DYNARRAY_NAME (emplace__) (list)); + return DYNARRAY_NAME (emplace__tail__) (list); +} + +/* Change the size of *LIST to SIZE. If SIZE is larger than the + existing size, new elements are added (which can be initialized). + Otherwise, the list is truncated, and elements are freed. Return + false on memory allocation failure (and mark *LIST as failed). */ +__attribute_maybe_unused__ __attribute_nonnull__ ((1)) +static bool +DYNARRAY_NAME (resize) (struct DYNARRAY_STRUCT *list, size_t size) +{ + if (size > list->u.dynarray_header.used) + { + bool ok; +#if defined (DYNARRAY_ELEMENT_INIT) + /* The new elements have to be initialized. */ + size_t old_size = list->u.dynarray_header.used; + ok = __libc_dynarray_resize (&list->u.dynarray_abstract, + size, DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)); + if (ok) + for (size_t i = old_size; i < size; ++i) + { + DYNARRAY_ELEMENT_INIT (&list->u.dynarray_header.array[i]); + } +#elif defined (DYNARRAY_ELEMENT_FREE) + /* Zero initialization is needed so that the elements can be + safely freed. */ + ok = __libc_dynarray_resize_clear + (&list->u.dynarray_abstract, size, + DYNARRAY_SCRATCH (list), sizeof (DYNARRAY_ELEMENT)); +#else + ok = __libc_dynarray_resize (&list->u.dynarray_abstract, + size, DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)); +#endif + if (__glibc_unlikely (!ok)) + DYNARRAY_NAME (mark_failed) (list); + return ok; + } + else + { + /* The list has shrunk in size. Free the removed elements. */ + DYNARRAY_NAME (free__elements__) + (list->u.dynarray_header.array + size, + list->u.dynarray_header.used - size); + list->u.dynarray_header.used = size; + return true; + } +} + +/* Remove the last element of LIST if it is present. */ +__attribute_maybe_unused__ __attribute_nonnull__ ((1)) +static void +DYNARRAY_NAME (remove_last) (struct DYNARRAY_STRUCT *list) +{ + /* used > 0 implies that the array is the non-failed state. */ + if (list->u.dynarray_header.used > 0) + { + size_t new_length = list->u.dynarray_header.used - 1; +#ifdef DYNARRAY_ELEMENT_FREE + DYNARRAY_ELEMENT_FREE (&list->u.dynarray_header.array[new_length]); +#endif + list->u.dynarray_header.used = new_length; + } +} + +/* Remove all elements from the list. The elements are freed, but the + list itself is not. */ +__attribute_maybe_unused__ __attribute_nonnull__ ((1)) +static void +DYNARRAY_NAME (clear) (struct DYNARRAY_STRUCT *list) +{ + /* free__elements__ does nothing if the list is in the failed + state. */ + DYNARRAY_NAME (free__elements__) + (list->u.dynarray_header.array, list->u.dynarray_header.used); + list->u.dynarray_header.used = 0; +} + +#ifdef DYNARRAY_FINAL_TYPE +/* Transfer the dynamic array to a permanent location at *RESULT. + Returns true on success on false on allocation failure. In either + case, *LIST is re-initialized and can be reused. A NULL pointer is + stored in *RESULT if LIST refers to an empty list. On success, the + pointer in *RESULT is heap-allocated and must be deallocated using + free. */ +__attribute_maybe_unused__ __attribute_warn_unused_result__ +__attribute_nonnull__ ((1, 2)) +static bool +DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list, + DYNARRAY_FINAL_TYPE *result) +{ + struct dynarray_finalize_result res; + if (__libc_dynarray_finalize (&list->u.dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT), &res)) + { + /* On success, the result owns all the data. */ + DYNARRAY_NAME (init) (list); + *result = (DYNARRAY_FINAL_TYPE) { res.array, res.length }; + return true; + } + else + { + /* On error, we need to free all data. */ + DYNARRAY_FREE (list); + errno = ENOMEM; + return false; + } +} +#else /* !DYNARRAY_FINAL_TYPE */ +/* Transfer the dynamic array to a heap-allocated array and return a + pointer to it. The pointer is NULL if memory allocation fails, or + if the array is empty, so this function should be used only for + arrays which are known not be empty (usually because they always + have a sentinel at the end). If LENGTHP is not NULL, the array + length is written to *LENGTHP. *LIST is re-initialized and can be + reused. */ +__attribute_maybe_unused__ __attribute_warn_unused_result__ +__attribute_nonnull__ ((1)) +static DYNARRAY_ELEMENT * +DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list, size_t *lengthp) +{ + struct dynarray_finalize_result res; + if (__libc_dynarray_finalize (&list->u.dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT), &res)) + { + /* On success, the result owns all the data. */ + DYNARRAY_NAME (init) (list); + if (lengthp != NULL) + *lengthp = res.length; + return res.array; + } + else + { + /* On error, we need to free all data. */ + DYNARRAY_FREE (list); + errno = ENOMEM; + return NULL; + } +} +#endif /* !DYNARRAY_FINAL_TYPE */ + +/* Undo macro definitions. */ + +#undef DYNARRAY_CONCAT0 +#undef DYNARRAY_CONCAT1 +#undef DYNARRAY_NAME +#undef DYNARRAY_SCRATCH +#undef DYNARRAY_HAVE_SCRATCH + +#undef DYNARRAY_STRUCT +#undef DYNARRAY_ELEMENT +#undef DYNARRAY_PREFIX +#undef DYNARRAY_ELEMENT_FREE +#undef DYNARRAY_ELEMENT_INIT +#undef DYNARRAY_INITIAL_SIZE +#undef DYNARRAY_FINAL_TYPE diff --git a/lib/malloc/dynarray.h b/lib/malloc/dynarray.h new file mode 100644 index 0000000..a9a3b08 --- /dev/null +++ b/lib/malloc/dynarray.h @@ -0,0 +1,177 @@ +/* Type-safe arrays which grow dynamically. Shared definitions. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +/* To use the dynarray facility, you need to include + <malloc/dynarray-skeleton.c> and define the parameter macros + documented in that file. + + A minimal example which provides a growing list of integers can be + defined like this: + + struct int_array + { + // Pointer to result array followed by its length, + // as required by DYNARRAY_FINAL_TYPE. + int *array; + size_t length; + }; + + #define DYNARRAY_STRUCT dynarray_int + #define DYNARRAY_ELEMENT int + #define DYNARRAY_PREFIX dynarray_int_ + #define DYNARRAY_FINAL_TYPE struct int_array + #include <malloc/dynarray-skeleton.c> + + To create a three-element array with elements 1, 2, 3, use this + code: + + struct dynarray_int dyn; + dynarray_int_init (&dyn); + for (int i = 1; i <= 3; ++i) + { + int *place = dynarray_int_emplace (&dyn); + assert (place != NULL); + *place = i; + } + struct int_array result; + bool ok = dynarray_int_finalize (&dyn, &result); + assert (ok); + assert (result.length == 3); + assert (result.array[0] == 1); + assert (result.array[1] == 2); + assert (result.array[2] == 3); + free (result.array); + + If the elements contain resources which must be freed, define + DYNARRAY_ELEMENT_FREE appropriately, like this: + + struct str_array + { + char **array; + size_t length; + }; + + #define DYNARRAY_STRUCT dynarray_str + #define DYNARRAY_ELEMENT char * + #define DYNARRAY_ELEMENT_FREE(ptr) free (*ptr) + #define DYNARRAY_PREFIX dynarray_str_ + #define DYNARRAY_FINAL_TYPE struct str_array + #include <malloc/dynarray-skeleton.c> + + Compared to scratch buffers, dynamic arrays have the following + features: + + - They have an element type, and are not just an untyped buffer of + bytes. + + - When growing, previously stored elements are preserved. (It is + expected that scratch_buffer_grow_preserve and + scratch_buffer_set_array_size eventually go away because all + current users are moved to dynamic arrays.) + + - Scratch buffers have a more aggressive growth policy because + growing them typically means a retry of an operation (across an + NSS service module boundary), which is expensive. + + - For the same reason, scratch buffers have a much larger initial + stack allocation. */ + +#ifndef _DYNARRAY_H +#define _DYNARRAY_H + +#include <stddef.h> +#include <string.h> + +struct dynarray_header +{ + size_t used; + size_t allocated; + void *array; +}; + +/* Marker used in the allocated member to indicate that an error was + encountered. */ +static inline size_t +__dynarray_error_marker (void) +{ + return -1; +} + +/* Internal function. See the has_failed function in + dynarray-skeleton.c. */ +static inline bool +__dynarray_error (struct dynarray_header *list) +{ + return list->allocated == __dynarray_error_marker (); +} + +/* Internal function. Enlarge the dynamically allocated area of the + array to make room for one more element. SCRATCH is a pointer to + the scratch area (which is not heap-allocated and must not be + freed). ELEMENT_SIZE is the size, in bytes, of one element. + Return false on failure, true on success. */ +bool __libc_dynarray_emplace_enlarge (struct dynarray_header *, + void *scratch, size_t element_size); + +/* Internal function. Enlarge the dynamically allocated area of the + array to make room for at least SIZE elements (which must be larger + than the existing used part of the dynamic array). SCRATCH is a + pointer to the scratch area (which is not heap-allocated and must + not be freed). ELEMENT_SIZE is the size, in bytes, of one element. + Return false on failure, true on success. */ +bool __libc_dynarray_resize (struct dynarray_header *, size_t size, + void *scratch, size_t element_size); + +/* Internal function. Like __libc_dynarray_resize, but clear the new + part of the dynamic array. */ +bool __libc_dynarray_resize_clear (struct dynarray_header *, size_t size, + void *scratch, size_t element_size); + +/* Internal type. */ +struct dynarray_finalize_result +{ + void *array; + size_t length; +}; + +/* Internal function. Copy the dynamically-allocated area to an + explicitly-sized heap allocation. SCRATCH is a pointer to the + embedded scratch space. ELEMENT_SIZE is the size, in bytes, of the + element type. On success, true is returned, and pointer and length + are written to *RESULT. On failure, false is returned. The caller + has to take care of some of the memory management; this function is + expected to be called from dynarray-skeleton.c. */ +bool __libc_dynarray_finalize (struct dynarray_header *list, void *scratch, + size_t element_size, + struct dynarray_finalize_result *result); + + +/* Internal function. Terminate the process after an index error. + SIZE is the number of elements of the dynamic array. INDEX is the + lookup index which triggered the failure. */ +_Noreturn void __libc_dynarray_at_failure (size_t size, size_t index); + +#ifndef _ISOMAC +libc_hidden_proto (__libc_dynarray_emplace_enlarge) +libc_hidden_proto (__libc_dynarray_resize) +libc_hidden_proto (__libc_dynarray_resize_clear) +libc_hidden_proto (__libc_dynarray_finalize) +libc_hidden_proto (__libc_dynarray_at_failure) +#endif + +#endif /* _DYNARRAY_H */ diff --git a/lib/malloc/dynarray_at_failure.c b/lib/malloc/dynarray_at_failure.c new file mode 100644 index 0000000..ebc9310 --- /dev/null +++ b/lib/malloc/dynarray_at_failure.c @@ -0,0 +1,40 @@ +/* Report an dynamic array index out of bounds condition. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +# include <stdlib.h> +#endif + +#include <dynarray.h> +#include <stdio.h> + +void +__libc_dynarray_at_failure (size_t size, size_t index) +{ +#ifdef _LIBC + char buf[200]; + __snprintf (buf, sizeof (buf), "Fatal glibc error: " + "array index %zu not less than array length %zu\n", + index, size); + __libc_fatal (buf); +#else + abort (); +#endif +} +libc_hidden_def (__libc_dynarray_at_failure) diff --git a/lib/malloc/dynarray_emplace_enlarge.c b/lib/malloc/dynarray_emplace_enlarge.c new file mode 100644 index 0000000..65aabb1 --- /dev/null +++ b/lib/malloc/dynarray_emplace_enlarge.c @@ -0,0 +1,77 @@ +/* Increase the size of a dynamic array in preparation of an emplace operation. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <dynarray.h> +#include <errno.h> +#include <stdckdint.h> +#include <stdlib.h> +#include <string.h> + +bool +__libc_dynarray_emplace_enlarge (struct dynarray_header *list, + void *scratch, size_t element_size) +{ + size_t new_allocated; + if (list->allocated == 0) + { + /* No scratch buffer provided. Choose a reasonable default + size. */ + if (element_size < 4) + new_allocated = 16; + else if (element_size < 8) + new_allocated = 8; + else + new_allocated = 4; + } + else + /* Increase the allocated size, using an exponential growth + policy. */ + { + new_allocated = list->allocated + list->allocated / 2 + 1; + if (new_allocated <= list->allocated) + { + /* Overflow. */ + __set_errno (ENOMEM); + return false; + } + } + + size_t new_size; + if (ckd_mul (&new_size, new_allocated, element_size)) + return false; + void *new_array; + if (list->array == scratch) + { + /* The previous array was not heap-allocated. */ + new_array = malloc (new_size); + if (new_array != NULL && list->array != NULL) + memcpy (new_array, list->array, list->used * element_size); + } + else + new_array = realloc (list->array, new_size); + if (new_array == NULL) + return false; + list->array = new_array; + list->allocated = new_allocated; + return true; +} +libc_hidden_def (__libc_dynarray_emplace_enlarge) diff --git a/lib/malloc/dynarray_finalize.c b/lib/malloc/dynarray_finalize.c new file mode 100644 index 0000000..673595a --- /dev/null +++ b/lib/malloc/dynarray_finalize.c @@ -0,0 +1,66 @@ +/* Copy the dynamically-allocated area to an explicitly-sized heap allocation. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <dynarray.h> +#include <stdlib.h> +#include <string.h> + +bool +__libc_dynarray_finalize (struct dynarray_header *list, + void *scratch, size_t element_size, + struct dynarray_finalize_result *result) +{ + if (__dynarray_error (list)) + /* The caller will reported the deferred error. */ + return false; + + size_t used = list->used; + + /* Empty list. */ + if (used == 0) + { + /* An empty list could still be backed by a heap-allocated + array. Free it if necessary. */ + if (list->array != scratch) + free (list->array); + *result = (struct dynarray_finalize_result) { NULL, 0 }; + return true; + } + + size_t allocation_size = used * element_size; + void *heap_array = malloc (allocation_size); + if (heap_array != NULL) + { + /* The new array takes ownership of the strings. */ + if (list->array != NULL) + memcpy (heap_array, list->array, allocation_size); + if (list->array != scratch) + free (list->array); + *result = (struct dynarray_finalize_result) + { .array = heap_array, .length = used }; + return true; + } + else + /* The caller will perform the freeing operation. */ + return false; +} +libc_hidden_def (__libc_dynarray_finalize) diff --git a/lib/malloc/dynarray_resize.c b/lib/malloc/dynarray_resize.c new file mode 100644 index 0000000..014f98c --- /dev/null +++ b/lib/malloc/dynarray_resize.c @@ -0,0 +1,68 @@ +/* Increase the size of a dynamic array. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <dynarray.h> +#include <errno.h> +#include <stdckdint.h> +#include <stdlib.h> +#include <string.h> + +bool +__libc_dynarray_resize (struct dynarray_header *list, size_t size, + void *scratch, size_t element_size) +{ + /* The existing allocation provides sufficient room. */ + if (size <= list->allocated) + { + list->used = size; + return true; + } + + /* Otherwise, use size as the new allocation size. The caller is + expected to provide the final size of the array, so there is no + over-allocation here. */ + + size_t new_size_bytes; + if (ckd_mul (&new_size_bytes, size, element_size)) + { + /* Overflow. */ + __set_errno (ENOMEM); + return false; + } + void *new_array; + if (list->array == scratch) + { + /* The previous array was not heap-allocated. */ + new_array = malloc (new_size_bytes); + if (new_array != NULL && list->array != NULL) + memcpy (new_array, list->array, list->used * element_size); + } + else + new_array = realloc (list->array, new_size_bytes); + if (new_array == NULL) + return false; + list->array = new_array; + list->allocated = size; + list->used = size; + return true; +} +libc_hidden_def (__libc_dynarray_resize) diff --git a/lib/malloc/dynarray_resize_clear.c b/lib/malloc/dynarray_resize_clear.c new file mode 100644 index 0000000..bb23c52 --- /dev/null +++ b/lib/malloc/dynarray_resize_clear.c @@ -0,0 +1,39 @@ +/* Increase the size of a dynamic array and clear the new part. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <dynarray.h> +#include <string.h> + +bool +__libc_dynarray_resize_clear (struct dynarray_header *list, size_t size, + void *scratch, size_t element_size) +{ + size_t old_size = list->used; + if (!__libc_dynarray_resize (list, size, scratch, element_size)) + return false; + /* __libc_dynarray_resize already checked for overflow. */ + char *array = list->array; + memset (array + (old_size * element_size), 0, + (size - old_size) * element_size); + return true; +} +libc_hidden_def (__libc_dynarray_resize_clear) diff --git a/lib/malloc/scratch_buffer.h b/lib/malloc/scratch_buffer.h new file mode 100644 index 0000000..33fd2b2 --- /dev/null +++ b/lib/malloc/scratch_buffer.h @@ -0,0 +1,135 @@ +/* Variable-sized buffer with on-stack default allocation. + Copyright (C) 2015-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _SCRATCH_BUFFER_H +#define _SCRATCH_BUFFER_H + +/* Scratch buffers with a default stack allocation and fallback to + heap allocation. It is expected that this function is used in this + way: + + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); + + while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) + if (!scratch_buffer_grow (&tmpbuf)) + return -1; + + scratch_buffer_free (&tmpbuf); + return 0; + + The allocation functions (scratch_buffer_grow, + scratch_buffer_grow_preserve, scratch_buffer_set_array_size) make + sure that the heap allocation, if any, is freed, so that the code + above does not have a memory leak. The buffer still remains in a + state that can be deallocated using scratch_buffer_free, so a loop + like this is valid as well: + + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); + + while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) + if (!scratch_buffer_grow (&tmpbuf)) + break; + + scratch_buffer_free (&tmpbuf); + + scratch_buffer_grow and scratch_buffer_grow_preserve are guaranteed + to grow the buffer by at least 512 bytes. This means that when + using the scratch buffer as a backing store for a non-character + array whose element size, in bytes, is 512 or smaller, the scratch + buffer only has to grow once to make room for at least one more + element. +*/ + +#include <stdbool.h> +#include <stddef.h> +#include <stdlib.h> + +/* Scratch buffer. Must be initialized with scratch_buffer_init + before its use. */ +struct scratch_buffer { + void *data; /* Pointer to the beginning of the scratch area. */ + size_t length; /* Allocated space at the data pointer, in bytes. */ + union { max_align_t __align; char __c[1024]; } __space; +}; + +/* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space + and BUFFER->length reflects the available space. */ +static inline void +scratch_buffer_init (struct scratch_buffer *buffer) +{ + buffer->data = buffer->__space.__c; + buffer->length = sizeof (buffer->__space); +} + +/* Deallocates *BUFFER (if it was heap-allocated). */ +static inline void +scratch_buffer_free (struct scratch_buffer *buffer) +{ + if (buffer->data != buffer->__space.__c) + free (buffer->data); +} + +/* Grow *BUFFER by some arbitrary amount. The buffer contents is NOT + preserved. Return true on success, false on allocation failure (in + which case the old buffer is freed). On success, the new buffer is + larger than the previous size. On failure, *BUFFER is deallocated, + but remains in a free-able state, and errno is set. */ +bool __libc_scratch_buffer_grow (struct scratch_buffer *buffer); +libc_hidden_proto (__libc_scratch_buffer_grow) + +/* Alias for __libc_scratch_buffer_grow. */ +static __always_inline bool +scratch_buffer_grow (struct scratch_buffer *buffer) +{ + return __glibc_likely (__libc_scratch_buffer_grow (buffer)); +} + +/* Like __libc_scratch_buffer_grow, but preserve the old buffer + contents on success, as a prefix of the new buffer. */ +bool __libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer); +libc_hidden_proto (__libc_scratch_buffer_grow_preserve) + +/* Alias for __libc_scratch_buffer_grow_preserve. */ +static __always_inline bool +scratch_buffer_grow_preserve (struct scratch_buffer *buffer) +{ + return __glibc_likely (__libc_scratch_buffer_grow_preserve (buffer)); +} + +/* Grow *BUFFER so that it can store at least NELEM elements of SIZE + bytes. The buffer contents are NOT preserved. Both NELEM and SIZE + can be zero. Return true on success, false on allocation failure + (in which case the old buffer is freed, but *BUFFER remains in a + free-able state, and errno is set). It is unspecified whether this + function can reduce the array size. */ +bool __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, + size_t nelem, size_t size); +libc_hidden_proto (__libc_scratch_buffer_set_array_size) + +/* Alias for __libc_scratch_set_array_size. */ +static __always_inline bool +scratch_buffer_set_array_size (struct scratch_buffer *buffer, + size_t nelem, size_t size) +{ + return __glibc_likely (__libc_scratch_buffer_set_array_size + (buffer, nelem, size)); +} + +#endif /* _SCRATCH_BUFFER_H */ diff --git a/lib/malloc/scratch_buffer_grow.c b/lib/malloc/scratch_buffer_grow.c new file mode 100644 index 0000000..a5e8f2f --- /dev/null +++ b/lib/malloc/scratch_buffer_grow.c @@ -0,0 +1,56 @@ +/* Variable-sized buffer with on-stack default allocation. + Copyright (C) 2015-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <scratch_buffer.h> +#include <errno.h> + +bool +__libc_scratch_buffer_grow (struct scratch_buffer *buffer) +{ + void *new_ptr; + size_t new_length = buffer->length * 2; + + /* Discard old buffer. */ + scratch_buffer_free (buffer); + + /* Check for overflow. */ + if (__glibc_likely (new_length >= buffer->length)) + new_ptr = malloc (new_length); + else + { + __set_errno (ENOMEM); + new_ptr = NULL; + } + + if (__glibc_unlikely (new_ptr == NULL)) + { + /* Buffer must remain valid to free. */ + scratch_buffer_init (buffer); + return false; + } + + /* Install new heap-based buffer. */ + buffer->data = new_ptr; + buffer->length = new_length; + return true; +} +libc_hidden_def (__libc_scratch_buffer_grow) diff --git a/lib/malloc/scratch_buffer_grow_preserve.c b/lib/malloc/scratch_buffer_grow_preserve.c new file mode 100644 index 0000000..c0b5d87 --- /dev/null +++ b/lib/malloc/scratch_buffer_grow_preserve.c @@ -0,0 +1,67 @@ +/* Variable-sized buffer with on-stack default allocation. + Copyright (C) 2015-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <scratch_buffer.h> +#include <errno.h> +#include <string.h> + +bool +__libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer) +{ + size_t new_length = 2 * buffer->length; + void *new_ptr; + + if (buffer->data == buffer->__space.__c) + { + /* Move buffer to the heap. No overflow is possible because + buffer->length describes a small buffer on the stack. */ + new_ptr = malloc (new_length); + if (new_ptr == NULL) + return false; + memcpy (new_ptr, buffer->__space.__c, buffer->length); + } + else + { + /* Buffer was already on the heap. Check for overflow. */ + if (__glibc_likely (new_length >= buffer->length)) + new_ptr = realloc (buffer->data, new_length); + else + { + __set_errno (ENOMEM); + new_ptr = NULL; + } + + if (__glibc_unlikely (new_ptr == NULL)) + { + /* Deallocate, but buffer must remain valid to free. */ + free (buffer->data); + scratch_buffer_init (buffer); + return false; + } + } + + /* Install new heap-based buffer. */ + buffer->data = new_ptr; + buffer->length = new_length; + return true; +} +libc_hidden_def (__libc_scratch_buffer_grow_preserve) diff --git a/lib/malloc/scratch_buffer_set_array_size.c b/lib/malloc/scratch_buffer_set_array_size.c new file mode 100644 index 0000000..24c3935 --- /dev/null +++ b/lib/malloc/scratch_buffer_set_array_size.c @@ -0,0 +1,64 @@ +/* Variable-sized buffer with on-stack default allocation. + Copyright (C) 2015-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <scratch_buffer.h> +#include <errno.h> +#include <limits.h> + +bool +__libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, + size_t nelem, size_t size) +{ + size_t new_length = nelem * size; + + /* Avoid overflow check if both values are small. */ + if ((nelem | size) >> (sizeof (size_t) * CHAR_BIT / 2) != 0 + && nelem != 0 && size != new_length / nelem) + { + /* Overflow. Discard the old buffer, but it must remain valid + to free. */ + scratch_buffer_free (buffer); + scratch_buffer_init (buffer); + __set_errno (ENOMEM); + return false; + } + + if (new_length <= buffer->length) + return true; + + /* Discard old buffer. */ + scratch_buffer_free (buffer); + + char *new_ptr = malloc (new_length); + if (new_ptr == NULL) + { + /* Buffer must remain valid to free. */ + scratch_buffer_init (buffer); + return false; + } + + /* Install new heap-based buffer. */ + buffer->data = new_ptr; + buffer->length = new_length; + return true; +} +libc_hidden_def (__libc_scratch_buffer_set_array_size) diff --git a/lib/malloca.c b/lib/malloca.c new file mode 100644 index 0000000..f055b1e --- /dev/null +++ b/lib/malloca.c @@ -0,0 +1,112 @@ +/* Safe automatic memory allocation. + Copyright (C) 2003, 2006-2007, 2009-2023 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2003, 2018. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +#define _GL_USE_STDLIB_ALLOC 1 +#include <config.h> + +/* Specification. */ +#include "malloca.h" + +#include <stdckdint.h> + +#include "idx.h" + +/* The speed critical point in this file is freea() applied to an alloca() + result: it must be fast, to match the speed of alloca(). The speed of + mmalloca() and freea() in the other case are not critical, because they + are only invoked for big memory sizes. + Here we use a bit in the address as an indicator, an idea by Ondřej Bílka. + malloca() can return three types of pointers: + - Pointers ≡ 0 mod 2*sa_alignment_max come from stack allocation. + - Pointers ≡ sa_alignment_max mod 2*sa_alignment_max come from heap + allocation. + - NULL comes from a failed heap allocation. */ + +/* Type for holding very small pointer differences. */ +typedef unsigned char small_t; +/* Verify that it is wide enough. */ +static_assert (2 * sa_alignment_max - 1 <= (small_t) -1); + +void * +mmalloca (size_t n) +{ +#if HAVE_ALLOCA + /* Allocate one more word, used to determine the address to pass to freea(), + and room for the alignment ≡ sa_alignment_max mod 2*sa_alignment_max. */ + uintptr_t alignment2_mask = 2 * sa_alignment_max - 1; + int plus = sizeof (small_t) + alignment2_mask; + idx_t nplus; + if (!ckd_add (&nplus, n, plus) && !xalloc_oversized (nplus, 1)) + { + char *mem = (char *) malloc (nplus); + + if (mem != NULL) + { + uintptr_t umem = (uintptr_t)mem, umemplus; + /* The ckd_add avoids signed integer overflow on + theoretical platforms where UINTPTR_MAX <= INT_MAX. */ + ckd_add (&umemplus, umem, sizeof (small_t) + sa_alignment_max - 1); + idx_t offset = ((umemplus & ~alignment2_mask) + + sa_alignment_max - umem); + void *vp = mem + offset; + small_t *p = vp; + /* Here p >= mem + sizeof (small_t), + and p <= mem + sizeof (small_t) + 2 * sa_alignment_max - 1 + hence p + n <= mem + nplus. + So, the memory range [p, p+n) lies in the allocated memory range + [mem, mem + nplus). */ + p[-1] = offset; + /* p ≡ sa_alignment_max mod 2*sa_alignment_max. */ + return p; + } + } + /* Out of memory. */ + return NULL; +#else +# if !MALLOC_0_IS_NONNULL + if (n == 0) + n = 1; +# endif + return malloc (n); +#endif +} + +#if HAVE_ALLOCA +void +freea (void *p) +{ + /* Check argument. */ + if ((uintptr_t) p & (sa_alignment_max - 1)) + { + /* p was not the result of a malloca() call. Invalid argument. */ + abort (); + } + /* Determine whether p was a non-NULL pointer returned by mmalloca(). */ + if ((uintptr_t) p & sa_alignment_max) + { + void *mem = (char *) p - ((small_t *) p)[-1]; + free (mem); + } +} +#endif + +/* + * Hey Emacs! + * Local Variables: + * coding: utf-8 + * End: + */ diff --git a/lib/malloca.h b/lib/malloca.h new file mode 100644 index 0000000..f68ddfe --- /dev/null +++ b/lib/malloca.h @@ -0,0 +1,132 @@ +/* Safe automatic memory allocation. + Copyright (C) 2003-2007, 2009-2023 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2003. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +#ifndef _MALLOCA_H +#define _MALLOCA_H + +/* This file uses _GL_ATTRIBUTE_ALLOC_SIZE, _GL_ATTRIBUTE_DEALLOC, + _GL_ATTRIBUTE_MALLOC, HAVE_ALLOCA. */ +#if !_GL_CONFIG_H_INCLUDED + #error "Please include config.h first." +#endif + +#include <alloca.h> +#include <stddef.h> +#include <stdlib.h> +#include <stdint.h> + +#include "xalloc-oversized.h" + + +#ifdef __cplusplus +extern "C" { +#endif + + +/* safe_alloca(N) is equivalent to alloca(N) when it is safe to call + alloca(N); otherwise it returns NULL. It either returns N bytes of + memory allocated on the stack, that lasts until the function returns, + or NULL. + Use of safe_alloca should be avoided: + - inside arguments of function calls - undefined behaviour, + - in inline functions - the allocation may actually last until the + calling function returns. +*/ +#if HAVE_ALLOCA +/* The OS usually guarantees only one guard page at the bottom of the stack, + and a page size can be as small as 4096 bytes. So we cannot safely + allocate anything larger than 4096 bytes. Also care for the possibility + of a few compiler-allocated temporary stack slots. + This must be a macro, not a function. */ +# define safe_alloca(N) ((N) < 4032 ? alloca (N) : NULL) +#else +# define safe_alloca(N) ((void) (N), NULL) +#endif + +/* Free a block of memory allocated through malloca(). */ +#if HAVE_ALLOCA +extern void freea (void *p); +#else +# define freea free +#endif + +/* malloca(N) is a safe variant of alloca(N). It allocates N bytes of + memory allocated on the stack, that must be freed using freea() before + the function returns. Upon failure, it returns NULL. */ +#if HAVE_ALLOCA +# define malloca(N) \ + ((N) < 4032 - (2 * sa_alignment_max - 1) \ + ? (void *) (((uintptr_t) (char *) alloca ((N) + 2 * sa_alignment_max - 1) \ + + (2 * sa_alignment_max - 1)) \ + & ~(uintptr_t)(2 * sa_alignment_max - 1)) \ + : mmalloca (N)) +#else +# define malloca(N) \ + mmalloca (N) +#endif +extern void *mmalloca (size_t n) + _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC (freea, 1) + _GL_ATTRIBUTE_ALLOC_SIZE ((1)); + +/* nmalloca(N,S) is an overflow-safe variant of malloca (N * S). + It allocates an array of N objects, each with S bytes of memory, + on the stack. N and S should be nonnegative and free of side effects. + The array must be freed using freea() before the function returns. */ +#define nmalloca(n, s) \ + (xalloc_oversized (n, s) ? NULL : malloca ((n) * (size_t) (s))) + + +#ifdef __cplusplus +} +#endif + + +/* ------------------- Auxiliary, non-public definitions ------------------- */ + +/* Determine the alignment of a type at compile time. */ +#if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__ +# define sa_alignof __alignof__ +#elif defined __cplusplus + template <class type> struct sa_alignof_helper { char __slot1; type __slot2; }; +# define sa_alignof(type) offsetof (sa_alignof_helper<type>, __slot2) +#elif defined __hpux + /* Work around a HP-UX 10.20 cc bug with enums constants defined as offsetof + values. */ +# define sa_alignof(type) (sizeof (type) <= 4 ? 4 : 8) +#elif defined _AIX + /* Work around an AIX 3.2.5 xlc bug with enums constants defined as offsetof + values. */ +# define sa_alignof(type) (sizeof (type) <= 4 ? 4 : 8) +#else +# define sa_alignof(type) offsetof (struct { char __slot1; type __slot2; }, __slot2) +#endif + +enum +{ +/* The desired alignment of memory allocations is the maximum alignment + among all elementary types. */ + sa_alignment_long = sa_alignof (long), + sa_alignment_double = sa_alignof (double), + sa_alignment_longlong = sa_alignof (long long), + sa_alignment_longdouble = sa_alignof (long double), + sa_alignment_max = ((sa_alignment_long - 1) | (sa_alignment_double - 1) + | (sa_alignment_longlong - 1) + | (sa_alignment_longdouble - 1) + ) + 1 +}; + +#endif /* _MALLOCA_H */ |