1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include "namespace.h" 36 #include <errno.h> 37 #include <stdio.h> 38 #include <string.h> 39 #include "un-namespace.h" 40 #include "local.h" 41 #include "libc_private.h" 42 43 /* 44 * Read at most n-1 characters from the given file. 45 * Stop when a newline has been read, or the count runs out. 46 * Return first argument, or NULL if no characters were read. 47 */ 48 char * 49 fgets(char * __restrict buf, int n, FILE * __restrict fp) 50 { 51 size_t len; 52 char *s, *ret; 53 unsigned char *p, *t; 54 55 FLOCKFILE_CANCELSAFE(fp); 56 ORIENT(fp, -1); 57 58 if (n <= 0) { /* sanity check */ 59 fp->_flags |= __SERR; 60 errno = EINVAL; 61 ret = NULL; 62 goto end; 63 } 64 65 s = buf; 66 n--; /* leave space for NUL */ 67 while (n != 0) { 68 /* 69 * If the buffer is empty, refill it. 70 */ 71 if ((len = fp->_r) <= 0) { 72 if (__srefill(fp)) { 73 /* EOF/error: stop with partial or no line */ 74 if (!__sfeof(fp) || s == buf) { 75 ret = NULL; 76 goto end; 77 } 78 break; 79 } 80 len = fp->_r; 81 } 82 p = fp->_p; 83 84 /* 85 * Scan through at most n bytes of the current buffer, 86 * looking for '\n'. If found, copy up to and including 87 * newline, and stop. Otherwise, copy entire chunk 88 * and loop. 89 */ 90 if (len > n) 91 len = n; 92 t = memchr((void *)p, '\n', len); 93 if (t != NULL) { 94 len = ++t - p; 95 fp->_r -= len; 96 fp->_p = t; 97 (void)memcpy((void *)s, (void *)p, len); 98 s[len] = 0; 99 ret = buf; 100 goto end; 101 } 102 fp->_r -= len; 103 fp->_p += len; 104 (void)memcpy((void *)s, (void *)p, len); 105 s += len; 106 n -= len; 107 } 108 *s = 0; 109 ret = buf; 110 end: 111 FUNLOCKFILE_CANCELSAFE(); 112 return (ret); 113 } 114