/* $OpenBSD: alloc.c,v 1.19 2018/01/16 22:52:32 jca Exp $ */ /* Public domain, like most of the rest of ksh */ /* * area-based allocation built on malloc/free */ #include <stdint.h> #include <stdlib.h> #include "sh.h" struct link { struct link *prev; struct link *next; }; Area * ainit(Area *ap) { ap->freelist = NULL; return ap; } void afreeall(Area *ap) { struct link *l, *l2; for (l = ap->freelist; l != NULL; l = l2) { l2 = l->next; free(l); } ap->freelist = NULL; } #define L2P(l) ( (void *)(((char *)(l)) + sizeof(struct link)) ) #define P2L(p) ( (struct link *)(((char *)(p)) - sizeof(struct link)) ) void * alloc(size_t size, Area *ap) { struct link *l; /* ensure that we don't overflow by allocating space for link */ if (size > SIZE_MAX - sizeof(struct link)) internal_errorf("unable to allocate memory"); l = malloc(sizeof(struct link) + size); if (l == NULL) internal_errorf("unable to allocate memory"); l->next = ap->freelist; l->prev = NULL; if (ap->freelist) ap->freelist->prev = l; ap->freelist = l; return L2P(l); } /* * Copied from calloc(). * * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW */ #define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 4)) void * areallocarray(void *ptr, size_t nmemb, size_t size, Area *ap) { /* condition logic cloned from calloc() */ if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && nmemb > 0 && SIZE_MAX / nmemb < size) { internal_errorf("unable to allocate memory"); } return aresize(ptr, nmemb * size, ap); } void * aresize(void *ptr, size_t size, Area *ap) { struct link *l, *l2, *lprev, *lnext; if (ptr == NULL) return alloc(size, ap); /* ensure that we don't overflow by allocating space for link */ if (size > SIZE_MAX - sizeof(struct link)) internal_errorf("unable to allocate memory"); l = P2L(ptr); lprev = l->prev; lnext = l->next; l2 = realloc(l, sizeof(struct link) + size); if (l2 == NULL) internal_errorf("unable to allocate memory"); if (lprev) lprev->next = l2; else ap->freelist = l2; if (lnext) lnext->prev = l2; return L2P(l2); } void afree(void *ptr, Area *ap) { struct link *l; if (!ptr) return; l = P2L(ptr); if (l->prev) l->prev->next = l->next; else ap->freelist = l->next; if (l->next) l->next->prev = l->prev; free(l); }