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/* memory.c
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* Minimal mmap-based malloc/free implementation to be used by libsandbox
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* internal routines, since we can't trust the current process to have a
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* malloc/free implementation that is sane and available at all times.
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*
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* Copyright 1999-2008 Gentoo Foundation
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* Licensed under the GPL-2
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*/
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#include "headers.h"
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#include "libsandbox.h"
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#include "sbutil.h"
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#define SB_MALLOC_TO_MMAP(ptr) ((void*)(((size_t*)ptr) - 1))
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#define SB_MMAP_TO_MALLOC(ptr) ((void*)(((size_t*)ptr) + 1))
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#define SB_MALLOC_TO_SIZE(ptr) (*((size_t*)SB_MALLOC_TO_MMAP(ptr)))
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void *malloc(size_t size)
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{
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size_t *ret;
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size += sizeof(size_t);
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ret = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
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if (ret == MAP_FAILED)
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return NULL;
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*ret = size;
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return SB_MMAP_TO_MALLOC(ret);
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}
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void free(void *ptr)
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{
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if (ptr == NULL)
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return;
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if (munmap(SB_MALLOC_TO_MMAP(ptr), SB_MALLOC_TO_SIZE(ptr))) {
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int color = ((is_env_on(ENV_NOCOLOR)) ? 0 : 1);
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SB_EERROR(color, "sandbox memory corruption", " free(%p): %s\n",
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ptr, strerror(errno));
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#ifdef HAVE_BACKTRACE
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void *funcs[10];
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int num_funcs;
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num_funcs = backtrace(funcs, sizeof(funcs));
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backtrace_symbols_fd(funcs, num_funcs, STDERR_FILENO);
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#endif
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}
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}
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void *calloc(size_t nmemb, size_t size)
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{
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void *ret;
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size_t malloc_size = nmemb * size;
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ret = malloc(malloc_size); /* dont care about overflow */
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if (ret == NULL)
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return NULL;
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memset(ret, 0x00, malloc_size);
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return ret;
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}
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void *realloc(void *ptr, size_t size)
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{
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void *ret;
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size_t old_malloc_size;
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if (ptr == NULL)
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return malloc(size);
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if (size == 0) {
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free(ptr);
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return ptr;
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}
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old_malloc_size = SB_MALLOC_TO_SIZE(ptr);
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ret = malloc(size);
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if (ret == NULL)
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return NULL;
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memcpy(ret, ptr, MIN(size, old_malloc_size));
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free(ptr);
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return ret;
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}
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char *strdup(const char *s)
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{
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size_t len;
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char *ret;
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if (s == NULL)
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return NULL;
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len = strlen(s);
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ret = malloc(len + 1);
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if (ret == NULL)
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return NULL;
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return memcpy(ret, s, len + 1);
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}
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