1/* alloc.c -- Memory allocation without mmap. 2 Copyright (C) 2012-2021 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. If ERROR_CALLBACK is NULL, don't 48 report an error. */ 49 50void * 51backtrace_alloc (struct backtrace_state *state ATTRIBUTE_UNUSED, 52 size_t size, backtrace_error_callback error_callback, 53 void *data) 54{ 55 void *ret; 56 57 ret = malloc (size); 58 if (ret == NULL) 59 { 60 if (error_callback) 61 error_callback (data, "malloc", errno); 62 } 63 return ret; 64} 65 66/* Free memory. */ 67 68void 69backtrace_free (struct backtrace_state *state ATTRIBUTE_UNUSED, 70 void *p, size_t size ATTRIBUTE_UNUSED, 71 backtrace_error_callback error_callback ATTRIBUTE_UNUSED, 72 void *data ATTRIBUTE_UNUSED) 73{ 74 free (p); 75} 76 77/* Grow VEC by SIZE bytes. */ 78 79void * 80backtrace_vector_grow (struct backtrace_state *state ATTRIBUTE_UNUSED, 81 size_t size, backtrace_error_callback error_callback, 82 void *data, struct backtrace_vector *vec) 83{ 84 void *ret; 85 86 if (size > vec->alc) 87 { 88 size_t alc; 89 void *base; 90 91 if (vec->size == 0) 92 alc = 32 * size; 93 else if (vec->size >= 4096) 94 alc = vec->size + 4096; 95 else 96 alc = 2 * vec->size; 97 98 if (alc < vec->size + size) 99 alc = vec->size + size; 100 101 base = realloc (vec->base, alc); 102 if (base == NULL) 103 { 104 error_callback (data, "realloc", errno); 105 return NULL; 106 } 107 108 vec->base = base; 109 vec->alc = alc - vec->size; 110 } 111 112 ret = (char *) vec->base + vec->size; 113 vec->size += size; 114 vec->alc -= size; 115 return ret; 116} 117 118/* Finish the current allocation on VEC. */ 119 120void * 121backtrace_vector_finish (struct backtrace_state *state, 122 struct backtrace_vector *vec, 123 backtrace_error_callback error_callback, 124 void *data) 125{ 126 void *ret; 127 128 /* With this allocator we call realloc in backtrace_vector_grow, 129 which means we can't easily reuse the memory here. So just 130 release it. */ 131 if (!backtrace_vector_release (state, vec, error_callback, data)) 132 return NULL; 133 ret = vec->base; 134 vec->base = NULL; 135 vec->size = 0; 136 vec->alc = 0; 137 return ret; 138} 139 140/* Release any extra space allocated for VEC. */ 141 142int 143backtrace_vector_release (struct backtrace_state *state ATTRIBUTE_UNUSED, 144 struct backtrace_vector *vec, 145 backtrace_error_callback error_callback, 146 void *data) 147{ 148 vec->alc = 0; 149 150 if (vec->size == 0) 151 { 152 /* As of C17, realloc with size 0 is marked as an obsolescent feature, use 153 free instead. */ 154 free (vec->base); 155 vec->base = NULL; 156 return 1; 157 } 158 159 vec->base = realloc (vec->base, vec->size); 160 if (vec->base == NULL) 161 { 162 error_callback (data, "realloc", errno); 163 return 0; 164 } 165 166 return 1; 167} 168