/*      $NetBSD: utils.c,v 1.6 2017/03/21 13:56:38 riastradh Exp $      */

/*-
 * Copyright (c) 2013 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Taylor R. Campbell.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__RCSID("$NetBSD: utils.c,v 1.6 2017/03/21 13:56:38 riastradh Exp $");

#include <sys/types.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"

/* XXX Seems to be missing from <stdio.h>...  */
int     snprintf_ss(char *restrict, size_t, const char *restrict, ...)
            __printflike(3, 4);
int     vsnprintf_ss(char *restrict, size_t, const char *restrict, va_list)
            __printflike(3, 0);

#include "utils.h"

/*
 * Read, returning partial data only at end of file.
 */
ssize_t
read_block(int fd, void *buf, size_t len)
{
        char *p = buf;
        size_t n = len;
        const char *const end __diagused = p + n;
        ssize_t nread = 0;

        while (0 < n && (nread = read(fd, p, n)) != 0) {
                if (nread == -1)
                        return -1;
                p += MIN(n, (size_t)nread);
                n -= MIN(n, (size_t)nread);
                assert(p + n == end);
        }

        assert(n == 0 || nread == 0); /* complete read or EOF */
        return len - n;
}

/*
 * Read from a specified position, returning partial data only at end
 * of file.
 */
ssize_t
pread_block(int fd, void *buf, size_t len, off_t fdpos)
{
        char *p = buf;
        size_t n = len;
        const char *const end __diagused = p + n;
        ssize_t nread = 0;

        assert(0 <= fdpos);
        assert(n <= OFF_MAX - (uintmax_t)fdpos);
        const off_t endpos __diagused = fdpos + n;

        while (0 < n && (nread = pread(fd, p, n, fdpos)) != 0) {
                if (nread == -1)
                        return -1;
                fdpos += MIN(n, (size_t)nread);
                p += MIN(n, (size_t)nread);
                n -= MIN(n, (size_t)nread);
                assert(p + n == end);
                assert(fdpos + (off_t)n == endpos);
        }

        assert(n == 0 || nread == 0); /* complete read or EOF */
        return len - n;
}

/*
 * Signal-safe err/warn utilities.  The errno varieties are limited to
 * having no format arguments for reasons of laziness.
 */

void
err_ss(int exit_value, const char *msg)
{
        warn_ss(msg);
        _Exit(exit_value);
}

void
errx_ss(int exit_value, const char *format, ...)
{
        va_list va;

        va_start(va, format);
        vwarnx_ss(format, va);
        va_end(va);
        _Exit(exit_value);
}

void
warn_ss(const char *msg)
{
        int error = errno;

        warnx_ss("%s: %s", msg, strerror(error));

        errno = error;
}

void
warnx_ss(const char *format, ...)
{
        va_list va;

        va_start(va, format);
        vwarnx_ss(format, va);
        va_end(va);
}

void
vwarnx_ss(const char *format, va_list va)
{
        char buf[128];

        (void)strlcpy(buf, getprogname(), sizeof(buf));
        (void)strlcat(buf, ": ", sizeof(buf));

        const int n = vsnprintf_ss(&buf[strlen(buf)], (sizeof(buf) -
                strlen(buf)), format, va);
        if (n <= 0) {
                const char fallback[] =
                    "vndcompress: Help!  I'm trapped in a signal handler!\n";
                (void)write(STDERR_FILENO, fallback, __arraycount(fallback));
        } else {
                (void)strlcat(buf, "\n", sizeof(buf));
                (void)write(STDERR_FILENO, buf, strlen(buf));
        }
}

void
block_signals(sigset_t *old_sigmask)
{
        sigset_t block;

        (void)sigfillset(&block);
        (void)sigprocmask(SIG_BLOCK, &block, old_sigmask);
}

void
restore_sigmask(const sigset_t *sigmask)
{

        (void)sigprocmask(SIG_SETMASK, sigmask, NULL);
}