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e5babf7541
Define MaxAllocSize in src/include/common/fe_memutils.h rather
than having several copies of it in different src/common/*.c files.
This also provides an opportunity to document it better.
Back-patch of commit 11b7de4a7, needed now because assorted security
fixes are adding additional references to MaxAllocSize in frontend
code.
Backpatch-through: 14-17
Security: CVE-2026-6473
101 lines
3.9 KiB
C
101 lines
3.9 KiB
C
/*
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* fe_memutils.h
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* memory management support for frontend code
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*
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* Copyright (c) 2003-2024, PostgreSQL Global Development Group
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*
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* src/include/common/fe_memutils.h
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*/
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#ifndef FE_MEMUTILS_H
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#define FE_MEMUTILS_H
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/*
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* Assumed maximum size for allocation requests.
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*
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* We don't enforce this, so the actual maximum is the platform's SIZE_MAX.
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* But it's useful to have it defined in frontend builds, so that common
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* code can check for oversized requests without having frontend-vs-backend
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* differences. Also, some code relies on MaxAllocSize being no more than
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* INT_MAX/2, so rather than setting this to SIZE_MAX, make it the same as
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* the backend's value.
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*/
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#define MaxAllocSize ((Size) 0x3fffffff) /* 1 gigabyte - 1 */
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/*
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* Flags for pg_malloc_extended and palloc_extended, deliberately named
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* the same as the backend flags.
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*/
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#define MCXT_ALLOC_HUGE 0x01 /* allow huge allocation (> 1 GB) not
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* actually used for frontends */
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#define MCXT_ALLOC_NO_OOM 0x02 /* no failure if out-of-memory */
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#define MCXT_ALLOC_ZERO 0x04 /* zero allocated memory */
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/*
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* "Safe" memory allocation functions --- these exit(1) on failure
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* (except pg_malloc_extended with MCXT_ALLOC_NO_OOM)
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*/
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extern char *pg_strdup(const char *in);
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extern void *pg_malloc(size_t size);
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extern void *pg_malloc0(size_t size);
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extern void *pg_malloc_extended(size_t size, int flags);
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extern void *pg_realloc(void *ptr, size_t size);
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extern void pg_free(void *ptr);
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/*
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* Support for safe calculation of memory request sizes
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*/
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extern Size add_size(Size s1, Size s2);
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extern Size mul_size(Size s1, Size s2);
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extern void *pg_malloc_mul(Size s1, Size s2);
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extern void *pg_malloc0_mul(Size s1, Size s2);
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extern void *pg_malloc_mul_extended(Size s1, Size s2, int flags);
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extern void *pg_realloc_mul(void *p, Size s1, Size s2);
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/*
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* Variants with easier notation and more type safety
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*/
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/*
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* Allocate space for one object of type "type"
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*/
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#define pg_malloc_object(type) ((type *) pg_malloc(sizeof(type)))
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#define pg_malloc0_object(type) ((type *) pg_malloc0(sizeof(type)))
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/*
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* Allocate space for "count" objects of type "type"
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*/
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#define pg_malloc_array(type, count) ((type *) pg_malloc_mul(sizeof(type), count))
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#define pg_malloc0_array(type, count) ((type *) pg_malloc0_mul(sizeof(type), count))
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#define pg_malloc_array_extended(type, count, flags) ((type *) pg_malloc_mul_extended(sizeof(type), count, flags))
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/*
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* Change size of allocation pointed to by "pointer" to have space for "count"
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* objects of type "type"
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*/
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#define pg_realloc_array(pointer, type, count) ((type *) pg_realloc_mul(pointer, sizeof(type), count))
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/* Equivalent functions, deliberately named the same as backend functions */
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extern char *pstrdup(const char *in);
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extern char *pnstrdup(const char *in, Size size);
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extern void *palloc(Size size);
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extern void *palloc0(Size size);
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extern void *palloc_extended(Size size, int flags);
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extern void *repalloc(void *pointer, Size size);
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extern void pfree(void *pointer);
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extern void *palloc_mul(Size s1, Size s2);
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extern void *palloc0_mul(Size s1, Size s2);
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extern void *palloc_mul_extended(Size s1, Size s2, int flags);
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extern void *repalloc_mul(void *p, Size s1, Size s2);
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#define palloc_object(type) ((type *) palloc(sizeof(type)))
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#define palloc0_object(type) ((type *) palloc0(sizeof(type)))
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#define palloc_array(type, count) ((type *) palloc_mul(sizeof(type), count))
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#define palloc0_array(type, count) ((type *) palloc0_mul(sizeof(type), count))
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#define palloc_array_extended(type, count, flags) ((type *) palloc_mul_extended(sizeof(type), count, flags))
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#define repalloc_array(pointer, type, count) ((type *) repalloc_mul(pointer, sizeof(type), count))
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/* sprintf into a palloc'd buffer --- these are in psprintf.c */
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extern char *psprintf(const char *fmt,...) pg_attribute_printf(1, 2);
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extern size_t pvsnprintf(char *buf, size_t len, const char *fmt, va_list args) pg_attribute_printf(3, 0);
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#endif /* FE_MEMUTILS_H */
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