1 /* $OpenBSD: asprintf.c,v 1.26 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 <stdarg.h> 24 #include <unistd.h> 25 #include "local.h" 26 27 #define INITIAL_SIZE 128 28 29 int 30 asprintf(char **str, const char *fmt, ...) 31 { 32 int ret; 33 va_list ap; 34 FILE f; 35 struct __sfileext fext; 36 const int pgsz = getpagesize(); 37 38 _FILEEXT_SETUP(&f, &fext); 39 f._file = -1; 40 f._flags = __SWR | __SSTR | __SALC; 41 f._bf._base = f._p = malloc(INITIAL_SIZE); 42 if (f._bf._base == NULL) 43 goto err; 44 f._bf._size = f._w = INITIAL_SIZE - 1; /* leave room for the NUL */ 45 va_start(ap, fmt); 46 ret = __vfprintf(&f, fmt, ap); 47 va_end(ap); 48 if (ret == -1) 49 goto err; 50 *f._p = '\0'; 51 if (ret + 1 > INITIAL_SIZE && ret + 1 < pgsz / 2) { 52 /* midsize allocations can try to conserve memory */ 53 unsigned char *_base = recallocarray(f._bf._base, 54 f._bf._size + 1, ret + 1, 1); 55 56 if (_base == NULL) 57 goto err; 58 *str = (char *)_base; 59 } else 60 *str = (char *)f._bf._base; 61 return (ret); 62 63 err: 64 free(f._bf._base); 65 f._bf._base = NULL; 66 *str = NULL; 67 errno = ENOMEM; 68 return (-1); 69 } 70 DEF_WEAK(asprintf); 71