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/* $OpenBSD: alloc.c,v 1.17 2017/08/15 17:57:57 jca Exp $ */ |
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/* Public domain, like most of the rest of ksh */ |
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/* |
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* area-based allocation built on malloc/free |
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*/ |
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#include <stdint.h> |
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#include <stdlib.h> |
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#include "sh.h" |
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struct link { |
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struct link *prev; |
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struct link *next; |
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}; |
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Area * |
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ainit(Area *ap) |
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{ |
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87504114 |
ap->freelist = NULL; |
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43752057 |
return ap; |
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} |
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void |
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afreeall(Area *ap) |
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{ |
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struct link *l, *l2; |
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✓✓ |
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for (l = ap->freelist; l != NULL; l = l2) { |
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l2 = l->next; |
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free(l); |
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} |
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ap->freelist = NULL; |
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} |
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#define L2P(l) ( (void *)(((char *)(l)) + sizeof(struct link)) ) |
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#define P2L(p) ( (struct link *)(((char *)(p)) - sizeof(struct link)) ) |
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void * |
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alloc(size_t size, Area *ap) |
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{ |
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struct link *l; |
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/* ensure that we don't overflow by allocating space for link */ |
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✗✓ |
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if (size > SIZE_MAX - sizeof(struct link)) |
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internal_errorf(1, "unable to allocate memory"); |
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l = calloc(1, sizeof(struct link) + size); |
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✗✓ |
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if (l == NULL) |
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internal_errorf(1, "unable to allocate memory"); |
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l->next = ap->freelist; |
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l->prev = NULL; |
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✓✓ |
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if (ap->freelist) |
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ap->freelist->prev = l; |
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ap->freelist = l; |
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return L2P(l); |
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} |
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/* |
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* Copied from calloc(). |
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* |
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* This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX |
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* if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW |
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*/ |
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#define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 4)) |
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void * |
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areallocarray(void *ptr, size_t nmemb, size_t size, Area *ap) |
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{ |
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/* condition logic cloned from calloc() */ |
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✗✓✗✗
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if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && |
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nmemb > 0 && SIZE_MAX / nmemb < size) { |
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internal_errorf(1, "unable to allocate memory"); |
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} |
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return aresize(ptr, nmemb * size, ap); |
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} |
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void * |
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aresize(void *ptr, size_t size, Area *ap) |
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{ |
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struct link *l, *l2, *lprev, *lnext; |
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✓✓ |
585543228 |
if (ptr == NULL) |
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return alloc(size, ap); |
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/* ensure that we don't overflow by allocating space for link */ |
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✗✓ |
162276352 |
if (size > SIZE_MAX - sizeof(struct link)) |
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internal_errorf(1, "unable to allocate memory"); |
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l = P2L(ptr); |
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lprev = l->prev; |
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lnext = l->next; |
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l2 = realloc(l, sizeof(struct link) + size); |
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✗✓ |
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if (l2 == NULL) |
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internal_errorf(1, "unable to allocate memory"); |
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if (lprev) |
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162276352 |
lprev->next = l2; |
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else |
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ap->freelist = l2; |
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✓✓ |
162276352 |
if (lnext) |
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lnext->prev = l2; |
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return L2P(l2); |
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} |
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void |
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afree(void *ptr, Area *ap) |
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{ |
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struct link *l; |
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✓✓ |
443043272 |
if (!ptr) |
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return; |
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l = P2L(ptr); |
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✓✓ |
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if (l->prev) |
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l->prev->next = l->next; |
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else |
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ap->freelist = l->next; |
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✓✓ |
194523478 |
if (l->next) |
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l->next->prev = l->prev; |
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free(l); |
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} |