1 /* $OpenBSD: vasprintf.c,v 1.23 2019/01/25 00:19:25 millert Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Todd C. Miller <millert@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <stdio.h> 20 #include <stdlib.h> 21 #include <string.h> 22 #include <errno.h> 23 #include <unistd.h> 24 #include "local.h" 25 26 #define INITIAL_SIZE 128 27 28 int 29 vasprintf(char **str, const char *fmt, __va_list ap) 30 { 31 int ret; 32 FILE f; 33 struct __sfileext fext; 34 const int pgsz = getpagesize(); 35 36 _FILEEXT_SETUP(&f, &fext); 37 f._file = -1; 38 f._flags = __SWR | __SSTR | __SALC; 39 f._bf._base = f._p = malloc(INITIAL_SIZE); 40 if (f._bf._base == NULL) 41 goto err; 42 f._bf._size = f._w = INITIAL_SIZE - 1; /* leave room for the NUL */ 43 ret = __vfprintf(&f, fmt, ap); 44 if (ret == -1) 45 goto err; 46 *f._p = '\0'; 47 if (ret + 1 > INITIAL_SIZE && ret + 1 < pgsz / 2) { 48 /* midsize allocations can try to conserve memory */ 49 unsigned char *_base = recallocarray(f._bf._base, 50 f._bf._size + 1, ret + 1, 1); 51 52 if (_base == NULL) 53 goto err; 54 *str = (char *)_base; 55 } else 56 *str = (char *)f._bf._base; 57 return (ret); 58 59 err: 60 free(f._bf._base); 61 f._bf._base = NULL; 62 *str = NULL; 63 errno = ENOMEM; 64 return (-1); 65 } 66 DEF_WEAK(vasprintf); 67