/*      $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);
}