SQLite

      sqlite3_str_appendall(pStr, zIn);
      sqlite3_str_appendchar(pStr, 1, '\'');
    }
#endif
  }
  return 0;
}

/* Add an approprate PATH= argument to the SSH command under construction
** in pStr
**
** About This Feature
** ==================
**
** On some ssh servers (Macs in particular are guilty of this) the PATH
** variable in the shell that runs the command that is sent to the remote
** host contains a limited number of read-only system directories:
**
**      /usr/bin:/bin:/usr/sbin:/sbin
**
** The sqlite3_rsync executable cannot be installed into any of those
** directories because they are locked down, and so the "sqlite3_rsync"
** command cannot run.
**
** To work around this, the sqlite3_rsync command is prefixed with a PATH=
** argument, inserted by this function, to augment the PATH with additional
** directories in which the sqlite3_rsync executable can be installed.
**
** But other ssh servers are confused by this initial PATH= argument.
** Some ssh servers have a list of programs that they are allowed to run
** and will fail if the first argument is not on that list, and PATH=....
** is not on that list.
**
** So that sqlite3_rsync can invoke itself on a remote system using ssh
** on a variety of platforms, the following algorithm is used:
**
**   *  First try running the sqlite3_rsync without any PATH= argument.
**      If that works (and it does on a majority of systems) then we are
**      done.
**
**   *  If the first attempt fails, then try again after adding the
**      PATH= prefix argument.  (This function is what adds that
**      argument.)
**
** A consequence of this is that if the remote system is a Mac, the
** "ssh" command always ends up being invoked twice.  If anybody knows a
** way around that problem, please bring it to the attention of the
** developers.
*/
void add_path_argument(sqlite3_str *pStr){
  append_escaped_arg(pStr,
     "PATH=$HOME/bin:/usr/local/bin:/opt/homebrew/bin:$PATH", 0);
}

/*****************************************************************************
** End of the append_escaped_arg() routine, adapted from the Fossil         **
*****************************************************************************/

/*****************************************************************************
** The Hash Engine
**

#endif
  while( zIn<zPath ){
    if( zIn[0]=='/' ) return 0;
    if( zIn[0]=='\\' ) return 0;
    zIn++;
  }
  return zPath;
}


/*
** Parse command-line arguments.  Dispatch subroutines to do the
** requested work.
**
** Input formats:
**

  if( ctx.zReplica==0 ){
    fprintf(stderr, "missing REPLICA database filename\n");
    return 1;
  }
  tmStart = currentTime();
  zDiv = hostSeparator(ctx.zOrigin);
  if( zDiv ){
    int iRetry;
    if( hostSeparator(ctx.zReplica)!=0 ){
      fprintf(stderr,
         "At least one of ORIGIN and REPLICA must be a local database\n"
         "You provided two remote databases.\n");
      return 1;
    }




    *(zDiv++) = 0;
    /* Remote ORIGIN and local REPLICA */
    for(iRetry=0; 1 /*exit-via-break*/; iRetry++){
      sqlite3_str *pStr = sqlite3_str_new(0);
      append_escaped_arg(pStr, zSsh, 1);
      sqlite3_str_appendf(pStr, " -e none");
      append_escaped_arg(pStr, ctx.zOrigin, 0);
      if( iRetry ) add_path_argument(pStr);
      append_escaped_arg(pStr, zExe, 1);
      append_escaped_arg(pStr, "--origin", 0);
      if( ctx.bCommCheck ){
        append_escaped_arg(pStr, "--commcheck", 0);
        if( ctx.eVerbose==0 ) ctx.eVerbose = 1;
      }
      if( zRemoteErrFile ){
        append_escaped_arg(pStr, "--errorfile", 0);
        append_escaped_arg(pStr, zRemoteErrFile, 1);
      }
      if( zRemoteDebugFile ){
        append_escaped_arg(pStr, "--debugfile", 0);
        append_escaped_arg(pStr, zRemoteDebugFile, 1);
      }
      if( ctx.bWalOnly ){
        append_escaped_arg(pStr, "--wal-only", 0);
      }
      append_escaped_arg(pStr, zDiv, 1);
      append_escaped_arg(pStr, file_tail(ctx.zReplica), 1);
      if( ctx.eVerbose<2 && iRetry==0 ){
        append_escaped_arg(pStr, "2>/dev/null", 0);
      }
      zCmd = sqlite3_str_finish(pStr);
      if( ctx.eVerbose>=2 ) printf("%s\n", zCmd);
      if( popen2(zCmd, &ctx.pIn, &ctx.pOut, &childPid, 0) ){
        if( iRetry>=1 ){
          fprintf(stderr, "Could not start auxiliary process: %s\n", zCmd);
          return 1;
        }
        if( ctx.eVerbose>=2 ){
          printf("ssh FAILED.  Retry with a PATH= argument...\n");
        }
        continue;
      }
      replicaSide(&ctx);
      if( ctx.nHashSent==0 && iRetry==0 ) continue;
      break;
    }
  }else if( (zDiv = hostSeparator(ctx.zReplica))!=0 ){
    /* Local ORIGIN and remote REPLICA */
    int iRetry;


    *(zDiv++) = 0;
    for(iRetry=0; 1 /*exit-by-break*/; iRetry++){
      sqlite3_str *pStr = sqlite3_str_new(0);
      append_escaped_arg(pStr, zSsh, 1);
      sqlite3_str_appendf(pStr, " -e none");
      append_escaped_arg(pStr, ctx.zReplica, 0);
      if( iRetry==1 ) add_path_argument(pStr);
      append_escaped_arg(pStr, zExe, 1);
      append_escaped_arg(pStr, "--replica", 0);
      if( ctx.bCommCheck ){
        append_escaped_arg(pStr, "--commcheck", 0);
        if( ctx.eVerbose==0 ) ctx.eVerbose = 1;
      }
      if( zRemoteErrFile ){
        append_escaped_arg(pStr, "--errorfile", 0);
        append_escaped_arg(pStr, zRemoteErrFile, 1);
      }
      if( zRemoteDebugFile ){
        append_escaped_arg(pStr, "--debugfile", 0);
        append_escaped_arg(pStr, zRemoteDebugFile, 1);
      }
      if( ctx.bWalOnly ){
        append_escaped_arg(pStr, "--wal-only", 0);
      }
      append_escaped_arg(pStr, file_tail(ctx.zOrigin), 1);
      append_escaped_arg(pStr, zDiv, 1);
      if( ctx.eVerbose<2 && iRetry==0 ){
        append_escaped_arg(pStr, "2>/dev/null", 0);
      }
      zCmd = sqlite3_str_finish(pStr);
      if( ctx.eVerbose>=2 ) printf("%s\n", zCmd);
      if( popen2(zCmd, &ctx.pIn, &ctx.pOut, &childPid, 0) ){
        if( iRetry>=1 ){
          fprintf(stderr, "Could not start auxiliary process: %s\n", zCmd);
          return 1;
        }else if( ctx.eVerbose>=2 ){
          printf("ssh FAILED.  Retry with a PATH= argument...\n");
        }
        continue;
      }
      originSide(&ctx);
      if( ctx.nHashSent==0 && iRetry==0 ) continue;
      break;
    }
  }else{
    /* Local ORIGIN and REPLICA */
    sqlite3_str *pStr = sqlite3_str_new(0);
    append_escaped_arg(pStr, argv[0], 1);
    append_escaped_arg(pStr, "--replica", 0);
    if( ctx.bCommCheck ){
      append_escaped_arg(pStr, "--commcheck", 0);