text: /* nbdkit
   * Copyright (C) 2013-2018 Red Hat Inc.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   * * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *
   * * 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.
   *
   * * Neither the name of Red Hat 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 RED HAT 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 RED HAT 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 <config.h>
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <stdarg.h>
  #include <string.h>
  #include <errno.h>
  
  #include "internal.h"
  
  /* Call the right nbdkit_verror function depending on log_sink.
   * Note: preserves the previous value of errno.
   */
  void
  nbdkit_verror (const char *fs, va_list args)
  {
    switch (log_to) {
    case LOG_TO_DEFAULT:
      if (forked_into_background)
        log_syslog_verror (fs, args);
      else
        log_stderr_verror (fs, args);
      break;
    case LOG_TO_SYSLOG:
      log_syslog_verror (fs, args);
      break;
    case LOG_TO_STDERR:
      log_stderr_verror (fs, args);
      break;
    case LOG_TO_NULL:
      /* nothing */
      break;
    }
  }
  
  /* Wrapper around nbdkit_verror.
   * Note: preserves the previous value of errno.
   */
  void
  nbdkit_error (const char *fs, ...)
  {
    va_list args;
  
    va_start (args, fs);
    nbdkit_verror (fs, args);
    va_end (args);
  }
  
  #if !HAVE_VFPRINTF_PERCENT_M
  /* Work around lack of %m in BSD */
  #undef vfprintf
  
  /* Call the real vfprintf after first changing %m into strerror(errno). */
  int
  nbdkit_vfprintf(FILE *f, const char *fmt, va_list args)
  {
    char *repl = NULL;
    char *p = strstr (fmt, "%m"); /* assume strstr doesn't touch errno */
    int ret;
  
    /* We only handle the first %m; if a user passes more than one, they
     * deserve broken output.
     */
    if (p && asprintf (&repl, "%.*s%s%s", (int) (p - fmt), fmt, strerror (errno),
                       p + 2) > 0)
      fmt = repl;
    ret = vfprintf (f, fmt, args);
    free (repl);
    return ret;
  }
  #endif
  