/* Copyright (c) 2000, 2010, Oracle and/or its affiliates Copyright (c) 2010, 2020, MariaDB This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */ /* Routines to handle mallocing of results which will be freed the same time */ #include #include #include #include #ifdef HAVE_SYS_MMAN_H #include #endif #undef EXTRA_DEBUG #define EXTRA_DEBUG #ifndef DBUG_OFF /* Put a protected barrier after every element when using multi_alloc_root() */ #define ALLOC_BARRIER #endif /* data packed in MEM_ROOT -> min_malloc */ /* Don't allocate too small blocks */ #define ROOT_MIN_BLOCK_SIZE 256 /* bits in MEM_ROOT->flags */ #define ROOT_FLAG_THREAD_SPECIFIC 1 #define ROOT_FLAG_MPROTECT 2 #define MALLOC_FLAG(R) MYF((R)->flags & ROOT_FLAG_THREAD_SPECIFIC ? THREAD_SPECIFIC : 0) #define TRASH_MEM(X) TRASH_FREE(((char*)(X) + ((X)->size-(X)->left)), (X)->left) /* Alloc memory through either my_malloc or mmap() */ static void *root_alloc(MEM_ROOT *root, size_t size, size_t *alloced_size, myf my_flags) { *alloced_size= size; #if defined(HAVE_MMAP) && defined(HAVE_MPROTECT) && defined(MAP_ANONYMOUS) if (root->flags & ROOT_FLAG_MPROTECT) { void *res; *alloced_size= MY_ALIGN(size, my_system_page_size); res= my_mmap(0, *alloced_size, PROT_READ | PROT_WRITE, MAP_NORESERVE | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (res == MAP_FAILED) res= 0; return res; } #endif /* HAVE_MMAP */ return my_malloc(root->psi_key, size, my_flags | MYF(root->flags & ROOT_FLAG_THREAD_SPECIFIC ? MY_THREAD_SPECIFIC : 0)); } static void root_free(MEM_ROOT *root, void *ptr, size_t size) { #if defined(HAVE_MMAP) && defined(HAVE_MPROTECT) && defined(MAP_ANONYMOUS) if (root->flags & ROOT_FLAG_MPROTECT) my_munmap(ptr, size); else #endif my_free(ptr); } /* Calculate block sizes to use Sizes will be updated to next power of 2, minus operating system memory management size. The idea is to reduce memory fragmentation as most system memory allocators are using power of 2 block size internally. */ static void calculate_block_sizes(MEM_ROOT *mem_root, size_t block_size, size_t *pre_alloc_size) { size_t pre_alloc= *pre_alloc_size; if (mem_root->flags&= ROOT_FLAG_MPROTECT) { mem_root->block_size= MY_ALIGN(block_size, my_system_page_size); if (pre_alloc) pre_alloc= MY_ALIGN(pre_alloc, my_system_page_size); } else { DBUG_ASSERT(block_size <= UINT_MAX32); mem_root->block_size= (my_round_up_to_next_power((uint32) block_size - MALLOC_OVERHEAD)- MALLOC_OVERHEAD); if (pre_alloc) pre_alloc= (my_round_up_to_next_power((uint32) pre_alloc - MALLOC_OVERHEAD)- MALLOC_OVERHEAD); } *pre_alloc_size= pre_alloc; } /* Initialize memory root SYNOPSIS init_alloc_root() key - key to register instrumented memory mem_root - memory root to initialize block_size - size of chunks (blocks) used for memory allocation. Will be updated to next power of 2, minus internal and system memory management size. This is will reduce memory fragmentation as most system memory allocators are using power of 2 block size internally. (It is external size of chunk i.e. it should include memory required for internal structures, thus it should be no less than ROOT_MIN_BLOCK_SIZE). pre_alloc_size - if non-0, then size of block that should be pre-allocated during memory root initialization. my_flags MY_THREAD_SPECIFIC flag for my_malloc MY_RROOT_USE_MPROTECT for read only protected memory DESCRIPTION This function prepares memory root for further use, sets initial size of chunk for memory allocation and pre-allocates first block if specified. Although error can happen during execution of this function if pre_alloc_size is non-0 it won't be reported. Instead it will be reported as error in first alloc_root() on this memory root. */ void init_alloc_root(PSI_memory_key key, MEM_ROOT *mem_root, size_t block_size, size_t pre_alloc_size __attribute__((unused)), myf my_flags) { DBUG_ENTER("init_alloc_root"); DBUG_PRINT("enter",("root: %p prealloc: %zu", mem_root, pre_alloc_size)); mem_root->free= mem_root->used= mem_root->pre_alloc= 0; mem_root->min_malloc= 32 + REDZONE_SIZE; mem_root->block_size= MY_MAX(block_size, ROOT_MIN_BLOCK_SIZE); mem_root->flags= 0; if (my_flags & MY_THREAD_SPECIFIC) mem_root->flags|= ROOT_FLAG_THREAD_SPECIFIC; if (my_flags & MY_ROOT_USE_MPROTECT) mem_root->flags|= ROOT_FLAG_MPROTECT; calculate_block_sizes(mem_root, block_size, &pre_alloc_size); mem_root->error_handler= 0; mem_root->block_num= 4; /* We shift this with >>2 */ mem_root->first_block_usage= 0; mem_root->psi_key= key; #if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) if (pre_alloc_size) { size_t alloced_size; if ((mem_root->free= mem_root->pre_alloc= (USED_MEM*) root_alloc(mem_root, pre_alloc_size, &alloced_size, MYF(0)))) { mem_root->free->size= alloced_size; mem_root->free->left= alloced_size - ALIGN_SIZE(sizeof(USED_MEM)); mem_root->free->next= 0; TRASH_MEM(mem_root->free); } } #endif DBUG_VOID_RETURN; } /* SYNOPSIS reset_root_defaults() mem_root memory root to change defaults of block_size new value of block size. Must be greater or equal than ALLOC_ROOT_MIN_BLOCK_SIZE (this value is about 68 bytes and depends on platform and compilation flags) pre_alloc_size new size of preallocated block. If not zero, must be equal to or greater than block size, otherwise means 'no prealloc'. DESCRIPTION Function aligns and assigns new value to block size; then it tries to reuse one of existing blocks as prealloc block, or malloc new one of requested size. If no blocks can be reused, all unused blocks are freed before allocation. */ void reset_root_defaults(MEM_ROOT *mem_root, size_t block_size, size_t pre_alloc_size __attribute__((unused))) { DBUG_ENTER("reset_root_defaults"); DBUG_ASSERT(alloc_root_inited(mem_root)); calculate_block_sizes(mem_root, block_size, &pre_alloc_size); #if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) if (pre_alloc_size) { size_t size= mem_root->block_size, alloced_size; if (!mem_root->pre_alloc || mem_root->pre_alloc->size != mem_root->block_size) { USED_MEM *mem, **prev= &mem_root->free; /* Free unused blocks, so that consequent calls to reset_root_defaults won't eat away memory. */ while (*prev) { mem= *prev; if (mem->size == size) { /* We found a suitable block, no need to do anything else */ mem_root->pre_alloc= mem; DBUG_VOID_RETURN; } if (mem->left + ALIGN_SIZE(sizeof(USED_MEM)) == mem->size) { /* remove block from the list and free it */ *prev= mem->next; root_free(mem_root, mem, mem->size); } else prev= &mem->next; } /* Allocate new prealloc block and add it to the end of free list */ if ((mem= (USED_MEM *) root_alloc(mem_root, size, &alloced_size, MYF(MY_WME)))) { mem->size= alloced_size; mem->left= alloced_size - ALIGN_SIZE(sizeof(USED_MEM)); mem->next= *prev; *prev= mem_root->pre_alloc= mem; TRASH_MEM(mem); } else mem_root->pre_alloc= 0; } } else #endif mem_root->pre_alloc= 0; DBUG_VOID_RETURN; } void *alloc_root(MEM_ROOT *mem_root, size_t length) { size_t get_size, block_size; uchar* point; reg1 USED_MEM *next= 0; reg2 USED_MEM **prev; size_t original_length __attribute__((unused)) = length; DBUG_ENTER("alloc_root"); DBUG_PRINT("enter",("root: %p", mem_root)); DBUG_ASSERT(alloc_root_inited(mem_root)); DBUG_EXECUTE_IF("simulate_out_of_memory", { if (mem_root->error_handler) (*mem_root->error_handler)(); DBUG_SET("-d,simulate_out_of_memory"); DBUG_RETURN((void*) 0); /* purecov: inspected */ }); #if defined(HAVE_valgrind) && defined(EXTRA_DEBUG) if (!(mem_root->flags & ROOT_FLAG_MPROTECT)) { length+= ALIGN_SIZE(sizeof(USED_MEM)); if (!(next = (USED_MEM*) my_malloc(mem_root->psi_key, length, MYF(MY_WME | ME_FATAL | (mem_root->flags & ROOT_FLAG_THREAD_SPECIFIC ? MY_THREAD_SPECIFIC : 0))))) { if (mem_root->error_handler) (*mem_root->error_handler)(); DBUG_RETURN((uchar*) 0); /* purecov: inspected */ } next->next= mem_root->used; next->left= 0; next->size= length; mem_root->used= next; DBUG_PRINT("exit",("ptr: %p", (((char*)next)+ALIGN_SIZE(sizeof(USED_MEM))))); DBUG_RETURN((((uchar*) next)+ALIGN_SIZE(sizeof(USED_MEM)))); } #endif /* defined(HAVE_valgrind) && defined(EXTRA_DEBUG) */ length= ALIGN_SIZE(length) + REDZONE_SIZE; if ((*(prev= &mem_root->free)) != NULL) { if ((*prev)->left < length && mem_root->first_block_usage++ >= ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP && (*prev)->left < ALLOC_MAX_BLOCK_TO_DROP) { next= *prev; *prev= next->next; /* Remove block from list */ next->next= mem_root->used; mem_root->used= next; mem_root->first_block_usage= 0; } for (next= *prev ; next && next->left < length ; next= next->next) prev= &next->next; } if (! next) { /* Time to alloc new block */ size_t alloced_length; /* Increase block size over time if there is a lot of mallocs */ block_size= (MY_ALIGN(mem_root->block_size, ROOT_MIN_BLOCK_SIZE) * (mem_root->block_num >> 2)- MALLOC_OVERHEAD); get_size= length + ALIGN_SIZE(sizeof(USED_MEM)); get_size= MY_MAX(get_size, block_size); if (!(next= (USED_MEM*) root_alloc(mem_root, get_size, &alloced_length, MYF(MY_WME | ME_FATAL)))) { if (mem_root->error_handler) (*mem_root->error_handler)(); DBUG_RETURN((void*) 0); /* purecov: inspected */ } mem_root->block_num++; next->next= *prev; next->size= alloced_length; next->left= alloced_length - ALIGN_SIZE(sizeof(USED_MEM)); *prev=next; TRASH_MEM(next); } point= (uchar*) ((char*) next+ (next->size-next->left)); /*TODO: next part may be unneded due to mem_root->first_block_usage counter*/ if ((next->left-= length) < mem_root->min_malloc) { /* Full block */ *prev= next->next; /* Remove block from list */ next->next= mem_root->used; mem_root->used= next; mem_root->first_block_usage= 0; } point+= REDZONE_SIZE; TRASH_ALLOC(point, original_length); DBUG_PRINT("exit",("ptr: %p", point)); DBUG_RETURN((void*) point); } /* Allocate many pointers at the same time. DESCRIPTION ptr1, ptr2, etc all point into big allocated memory area. SYNOPSIS multi_alloc_root() root Memory root ptr1, length1 Multiple arguments terminated by a NULL pointer ptr2, length2 ... ... NULL RETURN VALUE A pointer to the beginning of the allocated memory block in case of success or NULL if out of memory. */ void *multi_alloc_root(MEM_ROOT *root, ...) { va_list args; char **ptr, *start, *res; size_t tot_length, length; DBUG_ENTER("multi_alloc_root"); /* We don't need to do DBUG_PRINT here as it will be done when alloc_root is called */ va_start(args, root); tot_length= 0; while ((ptr= va_arg(args, char **))) { length= va_arg(args, uint); tot_length+= ALIGN_SIZE(length); #ifdef ALLOC_BARRIER tot_length+= ALIGN_SIZE(1); #endif } va_end(args); if (!(start= (char*) alloc_root(root, tot_length))) DBUG_RETURN(0); /* purecov: inspected */ va_start(args, root); res= start; while ((ptr= va_arg(args, char **))) { *ptr= res; length= va_arg(args, uint); res+= ALIGN_SIZE(length); #ifdef ALLOC_BARRIER TRASH_FREE(res, ALIGN_SIZE(1)); res+= ALIGN_SIZE(1); #endif } va_end(args); DBUG_RETURN((void*) start); } #if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) /** Mark all data in blocks free for reusage */ static inline void mark_blocks_free(MEM_ROOT* root) { reg1 USED_MEM *next; reg2 USED_MEM **last; /* iterate through (partially) free blocks, mark them free */ last= &root->free; for (next= root->free; next; next= *(last= &next->next)) { next->left= next->size - ALIGN_SIZE(sizeof(USED_MEM)); TRASH_MEM(next); } /* Combine the free and the used list */ *last= next=root->used; /* now go through the used blocks and mark them free */ for (; next; next= next->next) { next->left= next->size - ALIGN_SIZE(sizeof(USED_MEM)); TRASH_MEM(next); } /* Now everything is set; Indicate that nothing is used anymore */ root->used= 0; root->first_block_usage= 0; root->block_num= 4; } #endif /* Deallocate everything used by alloc_root or just move used blocks to free list if called with MY_USED_TO_FREE SYNOPSIS free_root() root Memory root MyFlags Flags for what should be freed: MY_MARK_BLOCKS_FREED Don't free blocks, just mark them free MY_KEEP_PREALLOC If this is not set, then free also the preallocated block NOTES One can call this function either with root block initialised with init_alloc_root() or with a bzero()-ed block. It's also safe to call this multiple times with the same mem_root. */ void free_root(MEM_ROOT *root, myf MyFlags) { reg1 USED_MEM *next,*old; DBUG_ENTER("free_root"); DBUG_PRINT("enter",("root: %p flags: %lu", root, MyFlags)); #if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) /* There is no point in using mark_blocks_free when using valgrind as it will not reclaim any memory */ if (MyFlags & MY_MARK_BLOCKS_FREE) { mark_blocks_free(root); DBUG_VOID_RETURN; } #endif if (!(MyFlags & MY_KEEP_PREALLOC)) root->pre_alloc=0; for (next=root->used; next ;) { old=next; next= next->next ; if (old != root->pre_alloc) root_free(root, old, old->size); } for (next=root->free ; next ;) { old=next; next= next->next; if (old != root->pre_alloc) root_free(root, old, old->size); } root->used=root->free=0; if (root->pre_alloc) { root->free=root->pre_alloc; root->free->left=root->pre_alloc->size-ALIGN_SIZE(sizeof(USED_MEM)); TRASH_MEM(root->pre_alloc); root->free->next=0; } root->block_num= 4; root->first_block_usage= 0; DBUG_VOID_RETURN; } /* Find block that contains an object and set the pre_alloc to it */ void set_prealloc_root(MEM_ROOT *root, char *ptr) { USED_MEM *next; for (next=root->used; next ; next=next->next) { if ((char*) next <= ptr && (char*) next + next->size > ptr) { root->pre_alloc=next; return; } } for (next=root->free ; next ; next=next->next) { if ((char*) next <= ptr && (char*) next + next->size > ptr) { root->pre_alloc=next; return; } } } /** Change protection for all blocks in the mem root */ #if defined(HAVE_MMAP) && defined(HAVE_MPROTECT) && defined(MAP_ANONYMOUS) void protect_root(MEM_ROOT *root, int prot) { reg1 USED_MEM *next,*old; DBUG_ENTER("protect_root"); DBUG_PRINT("enter",("root: %p prot: %d", root, prot)); DBUG_ASSERT(root->flags & ROOT_FLAG_MPROTECT); for (next= root->used; next ;) { old= next; next= next->next ; mprotect(old, old->size, prot); } for (next= root->free; next ;) { old= next; next= next->next ; mprotect(old, old->size, prot); } DBUG_VOID_RETURN; } #else void protect_root(MEM_ROOT *root, int prot) { } #endif /* defined(HAVE_MMAP) && ... */ char *strdup_root(MEM_ROOT *root, const char *str) { return strmake_root(root, str, strlen(str)); } char *strmake_root(MEM_ROOT *root, const char *str, size_t len) { char *pos; if ((pos=alloc_root(root,len+1))) { if (len) memcpy(pos,str,len); pos[len]=0; } return pos; } void *memdup_root(MEM_ROOT *root, const void *str, size_t len) { char *pos; if ((pos=alloc_root(root,len)) && len) memcpy(pos,str,len); return pos; } LEX_CSTRING safe_lexcstrdup_root(MEM_ROOT *root, const LEX_CSTRING str) { LEX_CSTRING res; if (str.length) res.str= strmake_root(root, str.str, str.length); else res.str= (const char *)""; res.length= str.length; return res; }