1/* alloc.c -- Memory allocation without mmap. 2 Copyright (C) 2012-2015 Free Software Foundation, Inc. 3 Written by Ian Lance Taylor, Google. 4 5Redistribution and use in source and binary forms, with or without 6modification, are permitted provided that the following conditions are 7met: 8 9 (1) Redistributions of source code must retain the above copyright 10 notice, this list of conditions and the following disclaimer. 11 12 (2) Redistributions in binary form must reproduce the above copyright 13 notice, this list of conditions and the following disclaimer in 14 the documentation and/or other materials provided with the 15 distribution. 16 17 (3) The name of the author may not be used to 18 endorse or promote products derived from this software without 19 specific prior written permission. 20 21THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 23WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 24DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 25INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 26(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 27SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 29STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 30IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31POSSIBILITY OF SUCH DAMAGE. */ 32 33#include "config.h" 34 35#include <errno.h> 36#include <stdlib.h> 37#include <sys/types.h> 38 39#include "backtrace.h" 40#include "internal.h" 41 42/* Allocation routines to use on systems that do not support anonymous 43 mmap. This implementation just uses malloc, which means that the 44 backtrace functions may not be safely invoked from a signal 45 handler. */ 46 47/* Allocate memory like malloc. */ 48 49void * 50backtrace_alloc (struct backtrace_state *state ATTRIBUTE_UNUSED, 51 size_t size, backtrace_error_callback error_callback, 52 void *data) 53{ 54 void *ret; 55 56 ret = malloc (size); 57 if (ret == NULL) 58 error_callback (data, "malloc", errno); 59 return ret; 60} 61 62/* Free memory. */ 63 64void 65backtrace_free (struct backtrace_state *state ATTRIBUTE_UNUSED, 66 void *p, size_t size ATTRIBUTE_UNUSED, 67 backtrace_error_callback error_callback ATTRIBUTE_UNUSED, 68 void *data ATTRIBUTE_UNUSED) 69{ 70 free (p); 71} 72 73/* Grow VEC by SIZE bytes. */ 74 75void * 76backtrace_vector_grow (struct backtrace_state *state ATTRIBUTE_UNUSED, 77 size_t size, backtrace_error_callback error_callback, 78 void *data, struct backtrace_vector *vec) 79{ 80 void *ret; 81 82 if (size > vec->alc) 83 { 84 size_t alc; 85 void *base; 86 87 if (vec->size == 0) 88 alc = 32 * size; 89 else if (vec->size >= 4096) 90 alc = vec->size + 4096; 91 else 92 alc = 2 * vec->size; 93 94 if (alc < vec->size + size) 95 alc = vec->size + size; 96 97 base = realloc (vec->base, alc); 98 if (base == NULL) 99 { 100 error_callback (data, "realloc", errno); 101 return NULL; 102 } 103 104 vec->base = base; 105 vec->alc = alc - vec->size; 106 } 107 108 ret = (char *) vec->base + vec->size; 109 vec->size += size; 110 vec->alc -= size; 111 return ret; 112} 113 114/* Finish the current allocation on VEC. */ 115 116void * 117backtrace_vector_finish (struct backtrace_state *state, 118 struct backtrace_vector *vec, 119 backtrace_error_callback error_callback, 120 void *data) 121{ 122 void *ret; 123 124 /* With this allocator we call realloc in backtrace_vector_grow, 125 which means we can't easily reuse the memory here. So just 126 release it. */ 127 if (!backtrace_vector_release (state, vec, error_callback, data)) 128 return NULL; 129 ret = vec->base; 130 vec->base = NULL; 131 vec->size = 0; 132 vec->alc = 0; 133 return ret; 134} 135 136/* Release any extra space allocated for VEC. */ 137 138int 139backtrace_vector_release (struct backtrace_state *state ATTRIBUTE_UNUSED, 140 struct backtrace_vector *vec, 141 backtrace_error_callback error_callback, 142 void *data) 143{ 144 vec->base = realloc (vec->base, vec->size); 145 if (vec->base == NULL) 146 { 147 error_callback (data, "realloc", errno); 148 return 0; 149 } 150 vec->alc = 0; 151 return 1; 152} 153