/* libmondo-fifo.c
   $Id: libmondo-fifo.c 30 2005-09-28 23:32:28Z bcornec $


04/17
- replaced INTERNAL_TAPE_BLK_SIZE with bkpinfo->internal_tape_block_size

04/04/2004
- ps wax is now ps wwax

09/10/2003
- p75 is now p80 in outopening tape call
- negotiate largest buffer possible when opening tape drive
- fall back to dd if buffer fails

09/09
- better logging for tape users
- working on try_hard_to_fwrite(), try_hard_to_fread()
- replaced internal w/ EXTERNAL 'buffer' exe.

08/30
- tweaked error msgs in try_hard_to_fwrite()

08/02
- updated is_incoming_block_valid() to make it
  return end-of-tape if >300 flotsam blocks

05/02
- when logging tape errors, don't repeat self

04/24
- added lots of log_OS_error()'s and assert()'s

04/22
- copy_file_from_here_to_there() --- added a bit of fault tolerance;
  if write fails, retry a few times before reporting error

04/07/2003
- line 866 --- set block_size used by internal buffer to 32768;
  was INTERNAL_TAPE_BLK_SIZE/2

10/01 - 11/30/2002
- is_incoming_block_valid() --- always make
  checksums %65536, just in case int size is
  odd (GRRR, ArkLinux)
- disabled rotor-related superfluous warnings
- added INTERNAL_TAPE_BLK_SIZE
- do_sem() now returns int explicitly
- changed internal_block_size
- some irregularities (e.g. bad 'type'-ing) found by Kylix; fixed by Hugo

09/01 - 09/30
- change 64k to TAPE_BLOCK_SIZE
- added internal_block_size; set it to TAPE_BLOCK_SIZE*2
- if data is flowing FROM tape TO hard disk then set the threshold to 10 (not 75)
- lots of multitape-related fixes
- finally caught & fixed the 'won't finish unzipping last bigfile' bug
- added WIFEXITED() after waitpid(), to improve multi-tape support

08/01 - 08/31
- trying to catch & stop 'won't finish unzipping last bigfile' bug by
  changing the copy_file_rom_here_to_there code
- changed % threshold from 95 back to 75
- don't insist on full 256K write of last block to tape
- if >25 secs go by & all data (AFAIK) has been copied thru by FIFO wrapper
  and g_tape_stream is _still_ not closed then shrug shoulders & pthread_exit
  anyway...
- change fprintf()'s to log_it()'s
- added a header+footer to each block as it is read/written to/from tape
  by copy_file_from_here_to_there
- wrote workaround to allow >2GB of archives w/buffering
- changed % threshold from 75 to 95
- added calls to set_signals(); 'buffer' was killing mondoarchive as
  it terminated
- cleaned up struct-passing, to improve reliability and eliminate
  some race conditions
- changed some forks to pthreads
- added some comments
- created libfifo{.c,.h,-EXT.h}
- copied core of 'buffer' here
- added some other, Mondo-specific functions
- hacked 'buffer' into user-friendliness
*/

/**
 * @file
 * Functions to handle buffering of tape archives as they are read/written.
 * This used the external program @c buffer mostly.
 */

#include <unistd.h>
#include <stdio.h>
#include <signal.h>
#include <fcntl.h>		
#include <stdio.h>
 
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/sem.h>
#include <sys/wait.h>
#include <pthread.h>

#include "my-stuff.h"
#include "mondostructures.h"
#include "libmondo.h"

/**
 * @addtogroup globalGroup
 * @{
 */
/**
 * The SIGPIPE handler sets this to TRUE.
 */
bool g_sigpipe=FALSE;

/**
 * PID of the "main" process.
 */
pid_t g_mastermind_pid=0;



/**
 * Command line with which @c buffer was invoked.
 */
char g_sz_call_to_buffer[MAX_STR_LEN];

/**
 * Size of the buffer used with @c buffer.
 */
int g_tape_buffer_size_MB=0;

/* @} - end of globalGroup */


/**
 * @addtogroup fifoGroup
 * @{
 */
/**
 * Open a pipe to/from @c buffer.
 * If buffer does not work at all, we use `dd'.
 * @param device The device to read from/write to.
 * @param direction @c 'r' (reading) or @c 'w' (writing).
 * @return A file pointer to/from the @c buffer process.
 */
FILE*open_device_via_buffer(char*device, char direction, long internal_tape_block_size)
{
  char sz_dir[32];
  char keych;
  char *tmp;
  char *command;
  FILE*fres;
  int bufsize; // in megabytes
  int res;
  int wise_upper_limit;
  int wise_lower_limit;

  malloc_string(tmp);
  malloc_string(command);
  assert_string_is_neither_NULL_nor_zerolength(device);
  assert(direction=='w'||direction=='r');
  sprintf(sz_dir, "%c", direction);
  wise_upper_limit = (am_I_in_disaster_recovery_mode() ? 8 : 32);
  wise_lower_limit = 1; // wise_upper_limit/2 + 1;
  paranoid_system("sync");
  for(bufsize=wise_upper_limit,res=-1; res!=0 && bufsize>=wise_lower_limit; bufsize--)
    {
      sprintf(tmp, "dd if=/dev/zero bs=1024 count=16k 2> /dev/null | buffer -o /dev/null -s %ld -m %d%c", internal_tape_block_size, bufsize, 'm');
      res = run_program_and_log_output(tmp, 2);
    }
  if (!res)
    {
      bufsize++;
      sprintf(tmp, "Negotiated max buffer of %d MB ", bufsize);
      log_to_screen(tmp);
    }
  else
    {
      bufsize=0;
      res=0;
      log_to_screen("Cannot negotiate a buffer of ANY size. Using dd instead.");
    }
  if (direction=='r')
    { keych = 'i'; }
  else
    { keych = 'o'; }
  if (bufsize)
    { sprintf(g_sz_call_to_buffer, "buffer -m %d%c -p%d -B -s%ld -%c %s 2>> %s", bufsize, 'm', (direction=='r')?20:75, internal_tape_block_size, keych, device, MONDO_LOGFILE); }
  else
    { sprintf(g_sz_call_to_buffer, "dd bs=%ld %cf=%s", internal_tape_block_size, keych, device); }
  log_msg (2, "Calling buffer --- command = '%s'", g_sz_call_to_buffer);
  fres = popen(g_sz_call_to_buffer, sz_dir);
  if (fres)
    { log_msg (2, "Successfully opened ('%c') tape device %s", direction, device); }
  else
    { log_msg (2, "Failed to open ('%c') tape device %s", direction, device); }
  sleep(2);
  sprintf(tmp, "ps wwax | grep \"%s\"", g_sz_call_to_buffer);
  if (run_program_and_log_output(tmp, 2))
    { log_msg(2, "Warning - I think I failed to open tape, actually."); }
  g_tape_buffer_size_MB = bufsize;
  strcmp(tmp, g_sz_call_to_buffer);
  tmp[30] = '\0';
  sprintf(command, "ps wwax | grep buffer | grep -v grep");
  if (run_program_and_log_output(command, 1))
    {
      fres = NULL;
      log_to_screen("Failed to open tape streamer. Buffer error.");
    }
  else
    {
      log_to_screen("Buffer successfully started.");
    }

  paranoid_free(command);
  paranoid_free(tmp);
  return(fres);
}


/**
 * Kill @c buffer processes.
 */
void kill_buffer()
{
  char *tmp;
  char *command;

  malloc_string(tmp);
  malloc_string(command);
  paranoid_system("sync");
  sprintf(command, "ps wwax | fgrep \"%s\" | fgrep -v grep | awk '{print $1;}' | grep -v PID | tr -s '\n' ' ' | awk '{ print $1; }'", g_sz_call_to_buffer);
  log_msg (2, "kill_buffer() --- command = %s", command);
  strcpy(tmp, call_program_and_get_last_line_of_output(command));
  sprintf(command, "kill %s", tmp);
  log_msg (2, "kill_buffer() --- command = %s", command);
  if (strlen(tmp)>0) { run_program_and_log_output(command, TRUE); }
  paranoid_free(tmp);
  paranoid_free(command);
}





/**
 * Handler for SIGPIPE.
 * @param sig The signal that occurred (hopefully SIGPIPE).
 */
void sigpipe_occurred(int sig)
{
  g_sigpipe = TRUE;
}

/* @} - end of fifoGroup */

int 
extract_config_file_from_ramdisk( struct s_bkpinfo *bkpinfo, 
				  char *ramdisk_fname, 
				  char *output_cfg_file, 
				  char *output_mountlist_file);
