diff options
Diffstat (limited to 'usr.bin/tail/misc.c')
| -rw-r--r-- | usr.bin/tail/misc.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/usr.bin/tail/misc.c b/usr.bin/tail/misc.c new file mode 100644 index 0000000..3b21e4e --- /dev/null +++ b/usr.bin/tail/misc.c @@ -0,0 +1,115 @@ +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Edward Sze-Tyan Wang. + * + * 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. + * 4. 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. + */ + +#include <sys/cdefs.h> + +__FBSDID("$FreeBSD$"); + +#ifndef lint +static const char sccsid[] = "@(#)misc.c 8.1 (Berkeley) 6/6/93"; +#endif + +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/mman.h> + +#include <err.h> +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "extern.h" + +void +ierr(const char *fname) +{ + warn("%s", fname); + rval = 1; +} + +void +oerr(void) +{ + err(1, "stdout"); +} + +/* + * Print `len' bytes from the file associated with `mip', starting at + * absolute file offset `startoff'. May move map window. + */ +int +mapprint(struct mapinfo *mip, off_t startoff, off_t len) +{ + int n; + + while (len > 0) { + if (startoff < mip->mapoff || startoff >= mip->mapoff + + (off_t)mip->maplen) { + if (maparound(mip, startoff) != 0) + return (1); + } + n = (mip->mapoff + mip->maplen) - startoff; + if (n > len) + n = len; + WR(mip->start + (startoff - mip->mapoff), n); + startoff += n; + len -= n; + } + return (0); +} + +/* + * Move the map window so that it contains the byte at absolute file + * offset `offset'. The start of the map window will be TAILMAPLEN + * aligned. + */ +int +maparound(struct mapinfo *mip, off_t offset) +{ + + if (mip->start != NULL && munmap(mip->start, mip->maplen) != 0) + return (1); + + mip->mapoff = offset & ~((off_t)TAILMAPLEN - 1); + mip->maplen = TAILMAPLEN; + if ((off_t)mip->maplen > mip->maxoff - mip->mapoff) + mip->maplen = mip->maxoff - mip->mapoff; + if (mip->maplen <= 0) + abort(); + if ((mip->start = mmap(NULL, mip->maplen, PROT_READ, MAP_SHARED, + mip->fd, mip->mapoff)) == MAP_FAILED) + return (1); + + return (0); +} |
