/* alloc.c -- Memory allocation without mmap.   Copyright (C) 2012-2026 Free Software Foundation, Inc.   Written by Ian Lance Taylor, Google. Redistribution and use in source and binary forms, with or withoutmodification, are permitted provided that the following conditions aremet:     (1) Redistributions of source code must retain the above copyright    notice, this list of conditions and the following disclaimer.     (2) Redistributions in binary form must reproduce the above copyright    notice, this list of conditions and the following disclaimer in    the documentation and/or other materials provided with the    distribution.     (3) The name of the author may not be used to    endorse or promote products derived from this software without    specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS ORIMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIEDWARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AREDISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS ORSERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISINGIN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THEPOSSIBILITY OF SUCH DAMAGE.  */ #include "config.h" #include <errno.h>#include <stdlib.h>#include <sys/types.h> #include "backtrace.h"#include "internal.h" /* Allocation routines to use on systems that do not support anonymous   mmap.  This implementation just uses malloc, which means that the   backtrace functions may not be safely invoked from a signal   handler.  */ /* Allocate memory like malloc.  If ERROR_CALLBACK is NULL, don't   report an error.  */ void *backtrace_alloc (struct backtrace_state *state ATTRIBUTE_UNUSED,		 size_t size, backtrace_error_callback error_callback,		 void *data){  void *ret;   ret = malloc (size);  if (ret == NULL)    {      if (error_callback)	error_callback (data, "malloc", errno);    }  return ret;} /* Free memory.  */ voidbacktrace_free (struct backtrace_state *state ATTRIBUTE_UNUSED,		void *p, size_t size ATTRIBUTE_UNUSED,		backtrace_error_callback error_callback ATTRIBUTE_UNUSED,		void *data ATTRIBUTE_UNUSED){  free (p);} /* Grow VEC by SIZE bytes.  */ void *backtrace_vector_grow (struct backtrace_state *state ATTRIBUTE_UNUSED,		       size_t size, backtrace_error_callback error_callback,		       void *data, struct backtrace_vector *vec){  void *ret;   if (size > vec->alc)    {      size_t alc;      void *base;       if (vec->size == 0)	alc = 32 * size;      else if (vec->size >= 4096)	alc = vec->size + 4096;      else	alc = 2 * vec->size;       if (alc < vec->size + size)	alc = vec->size + size;       base = realloc (vec->base, alc);      if (base == NULL)	{	  error_callback (data, "realloc", errno);	  return NULL;	}       vec->base = base;      vec->alc = alc - vec->size;    }   ret = (char *) vec->base + vec->size;  vec->size += size;  vec->alc -= size;  return ret;} /* Finish the current allocation on VEC.  */ void *backtrace_vector_finish (struct backtrace_state *state,			 struct backtrace_vector *vec,			 backtrace_error_callback error_callback,			 void *data){  void *ret;   /* With this allocator we call realloc in backtrace_vector_grow,     which means we can't easily reuse the memory here.  So just     release it.  */  if (!backtrace_vector_release (state, vec, error_callback, data))    return NULL;  ret = vec->base;  vec->base = NULL;  vec->size = 0;  vec->alc = 0;  return ret;} /* Release any extra space allocated for VEC.  */ intbacktrace_vector_release (struct backtrace_state *state ATTRIBUTE_UNUSED,			  struct backtrace_vector *vec,			  backtrace_error_callback error_callback,			  void *data){  vec->alc = 0;   if (vec->size == 0)    {      /* As of C17, realloc with size 0 is marked as an obsolescent feature, use	 free instead.  */      free (vec->base);      vec->base = NULL;      return 1;    }   vec->base = realloc (vec->base, vec->size);  if (vec->base == NULL)    {      error_callback (data, "realloc", errno);      return 0;    }   return 1;}