1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #include <err.h> 32 #include <errno.h> 33 #include <limits.h> 34 #include <stdio.h> 35 #include <stdlib.h> 36 #include <string.h> 37 38 static const char * 39 stream_name(FILE *s) 40 { 41 42 if (s == stdin) 43 return "stdin"; 44 if (s == stdout) 45 return "stdout"; 46 if (s == stderr) 47 return "stderr"; 48 /* This should not happen. */ 49 abort(); 50 } 51 52 static void 53 change_buf(FILE *s, const char *bufmode) 54 { 55 char *unit; 56 size_t bufsize; 57 int mode; 58 59 bufsize = 0; 60 if (bufmode[0] == '0' && bufmode[1] == '\0') 61 mode = _IONBF; 62 else if (bufmode[0] == 'L' && bufmode[1] == '\0') 63 mode = _IOLBF; 64 else if (bufmode[0] == 'B' && bufmode[1] == '\0') { 65 mode = _IOFBF; 66 bufsize = 0; 67 } else { 68 /* 69 * This library being preloaded, depending on libutil 70 * would lead to excessive namespace pollution. 71 * Thus we do not use expand_number(). 72 */ 73 errno = 0; 74 bufsize = strtol(bufmode, &unit, 0); 75 if (errno == EINVAL || errno == ERANGE || unit == bufmode) 76 warn("Wrong buffer mode '%s' for %s", bufmode, 77 stream_name(s)); 78 switch (*unit) { 79 case 'G': 80 bufsize *= 1024 * 1024 * 1024; 81 break; 82 case 'M': 83 bufsize *= 1024 * 1024; 84 break; 85 case 'k': 86 bufsize *= 1024; 87 break; 88 case '\0': 89 break; 90 default: 91 warnx("Unknown suffix '%c' for %s", *unit, 92 stream_name(s)); 93 return; 94 } 95 mode = _IOFBF; 96 } 97 if (setvbuf(s, NULL, mode, bufsize) != 0) 98 warn("Cannot set buffer mode '%s' for %s", bufmode, 99 stream_name(s)); 100 } 101 102 __attribute__ ((constructor)) static void 103 stdbuf(void) 104 { 105 char *i_mode, *o_mode, *e_mode; 106 107 i_mode = getenv("_STDBUF_I"); 108 o_mode = getenv("_STDBUF_O"); 109 e_mode = getenv("_STDBUF_E"); 110 111 if (e_mode != NULL) 112 change_buf(stderr, e_mode); 113 if (i_mode != NULL) 114 change_buf(stdin, i_mode); 115 if (o_mode != NULL) 116 change_buf(stdout, o_mode); 117 } 118