text: /* Dropbear Note: This file is based on OpenSSH 4.3p2. Avoid unnecessary
     changes to simplify future updates */
  
  /*
   * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   *
   * 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 AUTHOR ``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 AUTHOR 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.
   */
  
  /*RCSID("OpenBSD: misc.c,v 1.22 2003/09/18 08:49:45 markus Exp ");*/
  
  /* For xmalloc, xfree etc:
   * Author: Tatu Ylonen <ylo@cs.hut.fi>
   * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   *                    All rights reserved
   * Versions of malloc and friends that check their results, and never return
   * failure (they call fatal if they encounter an error).
   *
   * As far as I am concerned, the code I have written for this software
   * can be used freely for any purpose.  Any derived versions of this
   * software must be clearly marked as such, and if the derived work is
   * incompatible with the protocol description in the RFC file, it must be
   * called by a name other than "ssh" or "Secure Shell".
   */
  
  /*RCSID("OpenBSD: xmalloc.c,v 1.16 2001/07/23 18:21:46 stevesk Exp ");*/
  
  #define _GNU_SOURCE
  #include "scpmisc.h"
  
  #include "includes.h"
  
  void* xmalloc(size_t size)
  {
      void* ptr;
  
      if (size == 0)
      {
          fprintf(stderr, "xmalloc: zero size\n");
          exit(EXIT_FAILURE);
      }
      ptr = malloc(size);
      if (ptr == NULL)
      {
          fprintf(stderr, "xmalloc: out of memory (allocating %lu bytes)\n",
                  (u_long)size);
          exit(EXIT_FAILURE);
      }
      return ptr;
  }
  
  void* xrealloc(void* ptr, size_t new_size)
  {
      void* new_ptr;
  
      if (new_size == 0)
      {
          fprintf(stderr, "xrealloc: zero size\n");
          exit(EXIT_FAILURE);
      }
      if (ptr == NULL)
          new_ptr = malloc(new_size);
      else
          new_ptr = realloc(ptr, new_size);
      if (new_ptr == NULL)
      {
          fprintf(stderr, "xrealloc: out of memory (new_size %lu bytes)\n",
                  (u_long)new_size);
          exit(EXIT_FAILURE);
      }
      return new_ptr;
  }
  
  void xfree(void* ptr)
  {
      if (ptr == NULL)
      {
          fprintf(stderr, "xfree: NULL pointer given as argument\n");
          exit(EXIT_FAILURE);
      }
      free(ptr);
  }
  
  char* xstrdup(const char* str)
  {
      size_t len;
      char* cp;
  
      len = strlen(str) + 1;
      cp = xmalloc(len);
      strlcpy(cp, str, len);
      return cp;
  }
  
  char* cleanhostname(char* host)
  {
      if (*host == '[' && host[strlen(host) - 1] == ']')
      {
          host[strlen(host) - 1] = '\0';
          return (host + 1);
      }
      else
          return host;
  }
  
  char* colon(char* cp)
  {
      int flag = 0;
  
      if (*cp == ':') /* Leading colon is part of file name. */
          return (0);
      if (*cp == '[')
          flag = 1;
  
      for (; *cp; ++cp)
      {
          if (*cp == '@' && *(cp + 1) == '[')
              flag = 1;
          if (*cp == ']' && *(cp + 1) == ':' && flag)
              return (cp + 1);
          if (*cp == ':' && !flag)
              return (cp);
          if (*cp == '/')
              return (0);
      }
      return (0);
  }
  
  /* function to assist building execv() arguments */
  void addargs(arglist* args, char* fmt, ...)
  {
      va_list ap;
      char* cp;
      u_int nalloc;
      int r;
  
      va_start(ap, fmt);
      r = vasprintf(&cp, fmt, ap);
      va_end(ap);
      if (r == -1)
          fatal("addargs: argument too long");
  
      nalloc = args->nalloc;
      if (args->list == NULL)
      {
          nalloc = 32;
          args->num = 0;
      }
      else if (args->num + 2 >= nalloc)
          nalloc *= 2;
  
      args->list = xrealloc(args->list, nalloc * sizeof(char*));
      args->nalloc = nalloc;
      args->list[args->num++] = cp;
      args->list[args->num] = NULL;
  }
  
  void replacearg(arglist* args, u_int which, char* fmt, ...)
  {
      va_list ap;
      char* cp;
      int r;
  
      va_start(ap, fmt);
      r = vasprintf(&cp, fmt, ap);
      va_end(ap);
      if (r == -1)
          fatal("replacearg: argument too long");
  
      if (which >= args->num)
          fatal("replacearg: tried to replace invalid arg %d >= %d", which,
                args->num);
      xfree(args->list[which]);
      args->list[which] = cp;
  }
  
  void freeargs(arglist* args)
  {
      u_int i;
  
      if (args->list != NULL)
      {
          for (i = 0; i < args->num; i++)
              xfree(args->list[i]);
          xfree(args->list);
          args->nalloc = args->num = 0;
          args->list = NULL;
      }
  }
  
  /*
   * NB. duplicate __progname in case it is an alias for argv[0]
   * Otherwise it may get clobbered by setproctitle()
   */
  char* ssh_get_progname(char* argv0)
  {
      char* p;
  
      if (argv0 == NULL)
          return ("unknown"); /* XXX */
      p = strrchr(argv0, '/');
      if (p == NULL)
          p = argv0;
      else
          p++;
  
      return (xstrdup(p));
  }
  
  void fatal(char* fmt, ...)
  {
      va_list args;
      va_start(args, fmt);
      vfprintf(stderr, fmt, args);
      va_end(args);
      fputc('\n', stderr);
      exit(255);
  }
  
  void sanitise_stdfd(void)
  {
      int nullfd, dupfd;
  
      if ((nullfd = dupfd = open(DROPBEAR_PATH_DEVNULL, O_RDWR)) == -1)
      {
          fprintf(stderr, "Couldn't open /dev/null: %s", strerror(errno));
          exit(1);
      }
      while (++dupfd <= 2)
      {
          /* Only clobber closed fds */
          if (fcntl(dupfd, F_GETFL, 0) >= 0)
              continue;
          if (dup2(nullfd, dupfd) == -1)
          {
              fprintf(stderr, "dup2: %s", strerror(errno));
              exit(1);
          }
      }
      if (nullfd > 2)
          close(nullfd);
  }
  