/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Chris Torek. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; 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) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)fgetln.c 8.2 (Berkeley) 1/2/94"; #endif /* LIBC_SCCS and not lint */ #include "namespace.h" #include #include #include #include #include #include "un-namespace.h" #include "libc_private.h" #include "local.h" /* * Expand the line buffer. Return -1 on error. */ int __slbexpand(FILE *fp, size_t newsize) { void *p; if (fp->_lb._size >= newsize) return (0); if (newsize > INT_MAX) { errno = ENOMEM; return (-1); } if ((p = realloc(fp->_lb._base, newsize)) == NULL) return (-1); fp->_lb._base = p; fp->_lb._size = newsize; return (0); } /* * Get an input line. The returned pointer often (but not always) * points into a stdio buffer. Fgetln does not alter the text of * the returned line (which is thus not a C string because it will * not necessarily end with '\0'), but does allow callers to modify * it if they wish. Thus, we set __SMOD in case the caller does. */ char * fgetln(FILE *fp, size_t *lenp) { unsigned char *p; char *ret; size_t len; size_t off; FLOCKFILE_CANCELSAFE(fp); ORIENT(fp, -1); /* make sure there is input */ if (fp->_r <= 0 && __srefill(fp)) { *lenp = 0; ret = NULL; goto end; } /* look for a newline in the input */ if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) { /* * Found one. Flag buffer as modified to keep fseek from * `optimising' a backward seek, in case the user stomps on * the text. */ p++; /* advance over it */ ret = (char *)fp->_p; *lenp = len = p - fp->_p; fp->_flags |= __SMOD; fp->_r -= len; fp->_p = p; goto end; } /* * We have to copy the current buffered data to the line buffer. * As a bonus, though, we can leave off the __SMOD. * * OPTIMISTIC is length that we (optimistically) expect will * accommodate the `rest' of the string, on each trip through the * loop below. */ #define OPTIMISTIC 80 for (len = fp->_r, off = 0;; len += fp->_r) { size_t diff; /* * Make sure there is room for more bytes. Copy data from * file buffer to line buffer, refill file and look for * newline. The loop stops only when we find a newline. */ if (__slbexpand(fp, len + OPTIMISTIC)) goto error; (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, len - off); off = len; if (__srefill(fp)) { if (__sfeof(fp)) break; goto error; } if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL) continue; /* got it: finish up the line (like code above) */ p++; diff = p - fp->_p; len += diff; if (__slbexpand(fp, len)) goto error; (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, diff); fp->_r -= diff; fp->_p = p; break; } *lenp = len; ret = (char *)fp->_lb._base; end: FUNLOCKFILE_CANCELSAFE(); return (ret); error: *lenp = 0; /* ??? */ fp->_flags |= __SERR; ret = NULL; goto end; }