percona-xtrabackup-2.4.21/dbug/dbug.c

/******************************************************************************
 *                                                                            *
 *                                 N O T I C E                                *
 *                                                                            *
 *                    Copyright Abandoned, 1987, Fred Fish                    *
 *                                                                            *
 *                                                                            *
 *      This previously copyrighted work has been placed into the  public     *
 *      domain  by  the  author  and  may be freely used for any purpose,     *
 *      private or commercial.                                                *
 *                                                                            *
 *      Because of the number of inquiries I was receiving about the  use     *
 *      of this product in commercially developed works I have decided to     *
 *      simply make it public domain to further its unrestricted use.   I     *
 *      specifically  would  be  most happy to see this material become a     *
 *      part of the standard Unix distributions by AT&T and the  Berkeley     *
 *      Computer  Science  Research Group, and a standard part of the GNU     *
 *      system from the Free Software Foundation.                             *
 *                                                                            *
 *      I would appreciate it, as a courtesy, if this notice is  left  in     *
 *      all copies and derivative works.  Thank you.                          *
 *                                                                            *
 *      The author makes no warranty of any kind  with  respect  to  this     *
 *      product  and  explicitly disclaims any implied warranties of mer-     *
 *      chantability or fitness for any particular purpose.                   *
 *                                                                            *
 ******************************************************************************
 */

/*
 *  FILE
 *
 *      dbug.c   runtime support routines for dbug package
 *
 *  SCCS
 *
 *      @(#)dbug.c      1.25    7/25/89
 *
 *  DESCRIPTION
 *
 *      These are the runtime support routines for the dbug package.
 *      The dbug package has two main components; the user include
 *      file containing various macro definitions, and the runtime
 *      support routines which are called from the macro expansions.
 *
 *      Externally visible functions in the runtime support module
 *      use the naming convention pattern "_db_xx...xx_", thus
 *      they are unlikely to collide with user defined function names.
 *
 *  AUTHOR(S)
 *
 *      Fred Fish               (base code)
 *      Enhanced Software Technologies, Tempe, AZ
 *      asuvax!mcdphx!estinc!fnf
 *
 *      Binayak Banerjee        (profiling enhancements)
 *      seismo!bpa!sjuvax!bbanerje
 *
 *      Michael Widenius:
 *        DBUG_DUMP       - To dump a block of memory.
 *        PUSH_FLAG "O"   - To be used insted of "o" if we
 *                          want flushing after each write
 *        PUSH_FLAG "A"   - as 'O', but we will append to the out file instead
 *                          of creating a new one.
 *        Check of malloc on entry/exit (option "S")
 *
 *      Sergei Golubchik:
 *        DBUG_EXECUTE_IF
 *        incremental mode (-#+t:-d,info ...)
 *        DBUG_SET, _db_explain_
 *        thread-local settings
 *        negative lists (-#-d,info => everything but "info")
 *
 *        function/ syntax
 *        (the logic is - think of a call stack as of a path.
 *        "function" means only this function, "function/" means the hierarchy.
 *        in the future, filters like function1/function2 could be supported.
 *        following this logic glob(7) wildcards are supported.)
 *
 */

#include <my_global.h>
#include "my_sys.h"
#include <m_string.h>
#include <errno.h>
#include <ctype.h>
#include "thr_mutex.h"
#include "my_thread_local.h"

#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_FNMATCH_H
#include <fnmatch.h>
#else
#define fnmatch(A,B,C) strcmp(A,B)
#endif

#if defined(_WIN32)
#include <process.h>
#else
#include <signal.h>
#endif

#ifndef DBUG_OFF


/*
 *            Manifest constants which may be "tuned" if desired.
 */

#define PRINTBUF              1024    /* Print buffer size */
#define INDENT                2       /* Indentation per trace level */
#define MAXDEPTH              200     /* Maximum trace depth default */

/*
 *      The following flags are used to determine which
 *      capabilities the user has enabled with the settings
 *      push macro.
 *
 *      TRACE_ON is also used in _db_stack_frame_->level
 *      (until we add flags to _db_stack_frame_, increasing it by 4 bytes)
 */

#define DEBUG_ON        (1 <<  1)  /* Debug enabled */
#define FILE_ON         (1 <<  2)  /* File name print enabled */
#define LINE_ON         (1 <<  3)  /* Line number print enabled */
#define DEPTH_ON        (1 <<  4)  /* Function nest level print enabled */
#define PROCESS_ON      (1 <<  5)  /* Process name print enabled */
#define NUMBER_ON       (1 <<  6)  /* Number each line of output */
#define PROFILE_ON      (1 <<  7)  /* Print out profiling code */
#define PID_ON          (1 <<  8)  /* Identify each line with process id */
#define TIMESTAMP_ON    (1 <<  9)  /* timestamp every line of output */
#define FLUSH_ON_WRITE  (1 << 10)  /* Flush on every write */
#define OPEN_APPEND     (1 << 11)  /* Open for append      */
#define TRACE_ON        ((uint)1 << 31)  /* Trace enabled. MUST be the highest bit!*/

#define TRACING (cs->stack->flags & TRACE_ON)
#define DEBUGGING (cs->stack->flags & DEBUG_ON)
#define PROFILING (cs->stack->flags & PROFILE_ON)

/*
 *      Typedefs to make things more obvious.
 */

#define BOOLEAN my_bool

/*
 *      Make it easy to change storage classes if necessary.
 */

#define IMPORT extern           /* Names defined externally */
#define EXPORT                  /* Allocated here, available globally */

/*
 * The default file for profiling.  Could also add another flag
 * (G?) which allowed the user to specify this.
 *
 * If the automatic variables get allocated on the stack in
 * reverse order from their declarations, then define AUTOS_REVERSE to 1.
 * This is used by the code that keeps track of stack usage.  For
 * forward allocation, the difference in the dbug frame pointers
 * represents stack used by the callee function.  For reverse allocation,
 * the difference represents stack used by the caller function.
 *
 */

#define PROF_FILE       "dbugmon.out"
#define PROF_EFMT       "E\t%ld\t%s\n"
#define PROF_SFMT       "S\t%lx\t%lx\t%s\n"
#define PROF_XFMT       "X\t%ld\t%s\n"

#ifdef M_I386           /* predefined by xenix 386 compiler */
#define AUTOS_REVERSE 1
#else
#define AUTOS_REVERSE 0
#endif

/*
 *      Externally supplied functions.
 */

/*
 *      The user may specify a list of functions to trace or
 *      debug.  These lists are kept in a linear linked list,
 *      a very simple implementation.
 */

struct link {
    struct link *next_link;   /* Pointer to the next link */
    char   flags;
    char   str[1];            /* Pointer to link's contents */
};

/* flags for struct link and return flags of InList */
#define SUBDIR          1 /* this MUST be 1 */
#define INCLUDE         2
#define EXCLUDE         4
/* this is not a struct link flag, but only a return flags of InList */
#define MATCHED     65536
#define NOT_MATCHED     0

/*
 *      Debugging settings can be pushed or popped off of a
 *      stack which is implemented as a linked list.  Note
 *      that the head of the list is the current settings and the
 *      stack is pushed by adding a new settings to the head of the
 *      list or popped by removing the first link.
 *
 *      Note: if out_file is NULL, the other fields are not initialized at all!
 */

struct settings {
  uint flags;                   /* Current settings flags               */
  uint maxdepth;                /* Current maximum trace depth          */
  uint delay;                   /* Delay after each output line         */
  uint sub_level;               /* Sub this from code_state->level      */
  FILE *out_file;               /* Current output stream                */
  FILE *prof_file;              /* Current profiling stream             */
  char name[FN_REFLEN];         /* Name of output file                  */
  struct link *functions;       /* List of functions                    */
  struct link *p_functions;     /* List of profiled functions           */
  struct link *keywords;        /* List of debug keywords               */
  struct link *processes;       /* List of process names                */
  struct settings *next;        /* Next settings in the list            */
};

#define is_shared(S, V) ((S)->next && (S)->next->V == (S)->V)

/*
 *      Local variables not seen by user.
 */


static BOOLEAN init_done= FALSE; /* Set to TRUE when initialization done */
/**
  Global debugging settings.
  This structure shared between all threads,
  and is the last element in each thread @c CODE_STATE::stack chain.
  Protected by @c THR_LOCK_init_settings.
*/
static struct settings init_settings;
static const char *db_process= 0;/* Pointer to process name; argv[0] */
my_bool _dbug_on_= TRUE;	 /* FALSE if no debugging at all */

typedef struct _db_code_state_ {
  const char *process;          /* Pointer to process name; usually argv[0] */
  const char *func;             /* Name of current user function            */
  const char *file;             /* Name of current user file                */
  struct _db_stack_frame_ *framep; /* Pointer to current frame              */
  struct settings *stack;       /* debugging settings                       */
  const char *jmpfunc;          /* Remember current function for setjmp     */
  const char *jmpfile;          /* Remember current file for setjmp         */
  int lineno;                   /* Current debugger output line number      */
  uint level;                   /* Current function nesting level           */
  int jmplevel;                 /* Remember nesting level at setjmp()       */

/*
 *      The following variables are used to hold the state information
 *      between the call to _db_pargs_() and _db_doprnt_(), during
 *      expansion of the DBUG_PRINT macro.  This is the only macro
 *      that currently uses these variables.
 *
 *      These variables are currently used only by _db_pargs_() and
 *      _db_doprnt_().
 */

  uint u_line;                  /* User source code line number */
  int  locked;                  /* If locked with _db_lock_file_ */
  const char *u_keyword;        /* Keyword for current macro */
  uint m_read_lock_count;
} CODE_STATE;

/*
  The test below is so we could call functions with DBUG_ENTER before
  my_thread_init().
*/
#define get_code_state_if_not_set_or_return if (!cs && !((cs=code_state()))) return
#define get_code_state_or_return if (!((cs=code_state()))) return

        /* Handling lists */
#define ListAdd(A,B,C) ListAddDel(A,B,C,INCLUDE)
#define ListDel(A,B,C) ListAddDel(A,B,C,EXCLUDE)
static struct link *ListAddDel(struct link *, const char *, const char *, int);
static struct link *ListCopy(struct link *);
static int InList(struct link *linkp,const char *cp);
static uint ListFlags(struct link *linkp);
static void FreeList(struct link *linkp);
static int isseparator(const char *ptr);
        /* OpenClose debug output stream */
static void DBUGOpenFile(CODE_STATE *,const char *, const char *, int);
static void DBUGCloseFile(CODE_STATE *cs, FILE *fp);
        /* Push current debug settings */
static void PushState(CODE_STATE *cs);
	/* Free memory associated with debug state. */
static void FreeState (CODE_STATE *cs, struct settings *state, int free_state);
        /* Test for tracing enabled */
static int DoTrace(CODE_STATE *cs);
/*
  return values of DoTrace.
  Can also be used as bitmask: ret & DO_TRACE
*/
#define DO_TRACE        1
#define DONT_TRACE      2
#define ENABLE_TRACE    3
#define DISABLE_TRACE   4

static void DoPrefix(CODE_STATE *cs, uint line);
static BOOLEAN Writable(const char *pathname);

static char *DbugMalloc(size_t size);
static const char *BaseName(const char *pathname);
static void Indent(CODE_STATE *cs, int indent);
static void DbugFlush(CODE_STATE *);
static void DbugExit(const char *why);
static const char *DbugStrTok(const char *s);
static void DbugVfprintf(FILE *stream, const char* format, va_list args);

/*
 *      Miscellaneous printf format strings.
 */

#define ERR_MISSING_RETURN "missing DBUG_RETURN or DBUG_VOID_RETURN macro in function \"%s\"\n"
#define ERR_MISSING_UNLOCK "missing DBUG_UNLOCK_FILE macro in function \"%s\"\n"
#define ERR_OPEN "%s: can't open debug output stream \"%s\": "
#define ERR_CLOSE "%s: can't close debug file: "
#define ERR_ABORT "%s: debugger aborting because %s\n"


/*
** Macros to allow dbugging with threads
*/

static native_mutex_t THR_LOCK_dbug;

/**
  A mutex protecting flushing of gcov data, see _db_flush_gcov_().
  We don't re-use THR_LOCK_dbug, because that would disallow:
  DBUG_LOCK_FILE; ..... DBUG_SUICIDE(); .... DBUG_UNLOCK_FILE;
*/
static native_mutex_t THR_LOCK_gcov;

/**
  Lock, to protect @c init_settings.
  For performance reasons,
  the member @c init_settings.flags is not protected.
*/
static native_rw_lock_t THR_LOCK_init_settings;

static CODE_STATE *code_state(void)
{
  CODE_STATE *cs, **cs_ptr;

  /*
    _dbug_on_ is reset if we don't plan to use any debug commands at all and
    we want to run on maximum speed
   */
  if (!_dbug_on_)
    return 0;

  if (!init_done)
  {
    init_done=TRUE;
    native_mutex_init(&THR_LOCK_dbug, NULL);
    native_mutex_init(&THR_LOCK_gcov, NULL);
    native_rw_init(&THR_LOCK_init_settings);
    memset(&init_settings, 0, sizeof(init_settings));
    init_settings.out_file=stderr;
    init_settings.flags=OPEN_APPEND;
  }

  if (!(cs_ptr= my_thread_var_dbug()))
    return 0;                                   /* Thread not initialised */
  if (!(cs= *cs_ptr))
  {
    cs=(CODE_STATE*) DbugMalloc(sizeof(*cs));
    memset(cs, 0, sizeof(*cs));
    cs->process= db_process ? db_process : "dbug";
    cs->func="?func";
    cs->file="?file";
    cs->stack=&init_settings;
    cs->m_read_lock_count= 0;
    *cs_ptr= cs;
  }
  return cs;
}

/**
  Lock the stack debugging settings.
  Only the shared (global) settings are locked if necessary,
  per thread settings are local and safe to use.
  This lock is re entrant.
  @sa unlock_stack
*/
static void read_lock_stack(CODE_STATE *cs)
{
  if (cs->stack == &init_settings)
  {
    if (++(cs->m_read_lock_count) == 1)
      native_rw_rdlock(&THR_LOCK_init_settings);
  }
}

/**
  Unlock the stack debugging settings.
  @sa read_lock_stack
*/
static void unlock_stack(CODE_STATE *cs)
{
  if (cs->stack == &init_settings)
  {
    if (--(cs->m_read_lock_count) == 0)
      native_rw_unlock(&THR_LOCK_init_settings);
  }
}

/*
 *      Translate some calls among different systems.
 */

#ifdef HAVE_SLEEP
/* sleep() wants seconds */
#define Delay(A) sleep(((uint) A)/10)
#else
#define Delay(A) (0)
#endif

/*
 *  FUNCTION
 *
 *      _db_process_       give the name to the current process/thread
 *
 *  SYNOPSIS
 *
 *      VOID _process_(name)
 *      char *name;
 *
 */

void _db_process_(const char *name)
{
  CODE_STATE *cs;

  if (!db_process)
    db_process= name;

  get_code_state_or_return;
  cs->process= name;
}

/*
 *  FUNCTION
 *
 *      DbugParse  parse control string and set current debugger settings
 *
 *  DESCRIPTION
 *
 *      Given pointer to a debug control string in "control",
 *      parses the control string, and sets
 *      up a current debug settings.
 *
 *      The debug control string is a sequence of colon separated fields
 *      as follows:
 *
 *              [+]<field_1>:<field_2>:...:<field_N>
 *
 *      Each field consists of a mandatory flag character followed by
 *      an optional "," and comma separated list of modifiers:
 *
 *              [sign]flag[,modifier,modifier,...,modifier]
 *
 *      See the manual for the list of supported signs, flags, and modifiers
 *
 *      For convenience, any leading "-#" is stripped off.
 *
 *  RETURN
 *      1 - a list of functions ("f" flag) was possibly changed
 *      0 - a list of functions was not changed
 */

int DbugParse(CODE_STATE *cs, const char *control)
{
  const char *end;
  int rel, f_used=0;
  struct settings *stack;

  /*
    Make sure we are not changing settings while inside a
      DBUG_LOCK_FILE
      DBUG_UNLOCK_FILE
    section, that is a mis use, that would cause changing
    DBUG_FILE while the caller prints to it.
  */
  assert(! cs->locked);

  stack= cs->stack;

  /*
    When parsing the global init_settings itself,
    make sure to block every other thread using dbug functions.
  */
  assert(cs->m_read_lock_count == 0);
  if (stack == &init_settings)
    native_rw_wrlock(&THR_LOCK_init_settings);

  if (control[0] == '-' && control[1] == '#')
    control+=2;

  rel= control[0] == '+' || control[0] == '-';
  if ((!rel || (!stack->out_file && !stack->next)))
  {
    /* Free memory associated with the state before resetting its members */
    FreeState(cs, stack, 0);
    stack->flags= 0;
    stack->delay= 0;
    stack->maxdepth= 0;
    stack->sub_level= 0;
    stack->out_file= stderr;
    stack->prof_file= NULL;
    stack->functions= NULL;
    stack->p_functions= NULL;
    stack->keywords= NULL;
    stack->processes= NULL;
  }
  else if (!stack->out_file)
  {
    stack->flags= stack->next->flags;
    stack->delay= stack->next->delay;
    stack->maxdepth= stack->next->maxdepth;
    stack->sub_level= stack->next->sub_level;
    strcpy(stack->name, stack->next->name);
    stack->prof_file= stack->next->prof_file;
    if (stack->next == &init_settings)
    {
      assert(stack != &init_settings);
      native_rw_rdlock(&THR_LOCK_init_settings);

      /*
        Never share with the global parent - it can change under your feet.

        Reset out_file to stderr to prevent sharing of trace files between
        global and session settings.
      */
      stack->out_file= stderr;
      stack->functions= ListCopy(init_settings.functions);
      stack->p_functions= ListCopy(init_settings.p_functions);
      stack->keywords= ListCopy(init_settings.keywords);
      stack->processes= ListCopy(init_settings.processes);

      native_rw_unlock(&THR_LOCK_init_settings);
    }
    else
    {
      stack->out_file= stack->next->out_file;
      stack->functions= stack->next->functions;
      stack->p_functions= stack->next->p_functions;
      stack->keywords= stack->next->keywords;
      stack->processes= stack->next->processes;
    }
  }

  end= DbugStrTok(control);
  while (control < end)
  {
    int c, sign= (*control == '+') ? 1 : (*control == '-') ? -1 : 0;
    if (sign) control++;
    c= *control++;
    if (*control == ',') control++;
    /* XXX when adding new cases here, don't forget _db_explain_ ! */
    switch (c) {
    case 'd':
      if (sign < 0 && control == end)
      {
        if (!is_shared(stack, keywords))
          FreeList(stack->keywords);
        stack->keywords=NULL;
        stack->flags&= ~DEBUG_ON;
        break;
      }
      if (rel && is_shared(stack, keywords))
        stack->keywords= ListCopy(stack->keywords);
      if (sign < 0)
      {
        if (DEBUGGING)
        {
          stack->keywords= ListDel(stack->keywords, control, end);
          /* Turn off DEBUG_ON if it is last keyword to be removed. */
          if (stack->keywords == NULL)
            stack->flags&= ~DEBUG_ON;
        }
        break;
      }

      /* Do not add keyword if debugging all is enabled. */
      if (!(DEBUGGING && stack->keywords == NULL))
      {
        stack->keywords= ListAdd(stack->keywords, control, end);
        stack->flags|= DEBUG_ON;
      }

      /* If debug all is enabled, make the keyword list empty. */
      if (sign == 1 && control == end)
      {
        FreeList(stack->keywords);
        stack->keywords= NULL;
      }

      break;
    case 'D':
      stack->delay= atoi(control);
      break;
    case 'f':
      f_used= 1;
      if (sign < 0 && control == end)
      {
        if (!is_shared(stack,functions))
          FreeList(stack->functions);
        stack->functions=NULL;
        break;
      }
      if (rel && is_shared(stack,functions))
        stack->functions= ListCopy(stack->functions);
      if (sign < 0)
        stack->functions= ListDel(stack->functions, control, end);
      else
        stack->functions= ListAdd(stack->functions, control, end);
      break;
    case 'F':
      if (sign < 0)
        stack->flags &= ~FILE_ON;
      else
        stack->flags |= FILE_ON;
      break;
    case 'i':
      if (sign < 0)
        stack->flags &= ~PID_ON;
      else
        stack->flags |= PID_ON;
      break;
    case 'L':
      if (sign < 0)
        stack->flags &= ~LINE_ON;
      else
        stack->flags |= LINE_ON;
      break;
    case 'n':
      if (sign < 0)
        stack->flags &= ~DEPTH_ON;
      else
        stack->flags |= DEPTH_ON;
      break;
    case 'N':
      if (sign < 0)
        stack->flags &= ~NUMBER_ON;
      else
        stack->flags |= NUMBER_ON;
      break;
    case 'A':
    case 'O':
      stack->flags |= FLUSH_ON_WRITE;
      /* fall through */
    case 'a':
    case 'o':
      /* In case we already have an open file. */
      if (!is_shared(stack, out_file))
        DBUGCloseFile(cs, stack->out_file);
      if (sign < 0)
      {
        stack->flags &= ~FLUSH_ON_WRITE;
        stack->out_file= stderr;
        break;
      }
      if (c == 'a' || c == 'A')
        stack->flags |= OPEN_APPEND;
      else
        stack->flags &= ~OPEN_APPEND;
      if (control != end)
        DBUGOpenFile(cs, control, end, stack->flags & OPEN_APPEND);
      else
        DBUGOpenFile(cs, "-",0,0);
      break;
    case 'p':
      if (sign < 0 && control == end)
      {
        if (!is_shared(stack,processes))
          FreeList(stack->processes);
        stack->processes=NULL;
        break;
      }
      if (rel && is_shared(stack, processes))
        stack->processes= ListCopy(stack->processes);
      if (sign < 0)
        stack->processes= ListDel(stack->processes, control, end);
      else
        stack->processes= ListAdd(stack->processes, control, end);
      break;
    case 'P':
      if (sign < 0)
        stack->flags &= ~PROCESS_ON;
      else
        stack->flags |= PROCESS_ON;
      break;
    case 'r':
      stack->sub_level= cs->level;
      break;
    case 't':
      if (sign < 0)
      {
        if (control != end)
          stack->maxdepth-= atoi(control);
        else
          stack->maxdepth= 0;
      }
      else
      {
        if (control != end)
          stack->maxdepth+= atoi(control);
        else
          stack->maxdepth= MAXDEPTH;
      }
      if (stack->maxdepth > 0)
        stack->flags |= TRACE_ON;
      else
        stack->flags &= ~TRACE_ON;
      break;
    case 'T':
      if (sign < 0)
        stack->flags &= ~TIMESTAMP_ON;
      else
        stack->flags |= TIMESTAMP_ON;
      break;
    }
    if (!*end)
      break;
    control=end+1;
    end= DbugStrTok(control);
  }

  if (stack->next == &init_settings)
  {
    /*
      Enforce nothing is shared with the global init_settings
    */
    assert((stack->functions == NULL) || (stack->functions != init_settings.functions));
    assert((stack->p_functions == NULL) || (stack->p_functions != init_settings.p_functions));
    assert((stack->keywords == NULL) || (stack->keywords != init_settings.keywords));
    assert((stack->processes == NULL) || (stack->processes != init_settings.processes));
  }

  if (stack == &init_settings)
    native_rw_unlock(&THR_LOCK_init_settings);

  return !rel || f_used;
}

#define framep_trace_flag(cs, frp) (frp ?                                    \
                                     frp->level & TRACE_ON :                 \
                              (ListFlags(cs->stack->functions) & INCLUDE) ?  \
                                       0 : (uint)TRACE_ON)

void FixTraceFlags_helper(CODE_STATE *cs, const char *func,
                          struct _db_stack_frame_ *framep)
{
  if (framep->prev)
    FixTraceFlags_helper(cs, framep->func, framep->prev);

  cs->func= func;
  cs->level= framep->level & ~TRACE_ON;
  framep->level= cs->level | framep_trace_flag(cs, framep->prev);
  /*
    we don't set cs->framep correctly, even though DoTrace uses it.
    It's ok, because cs->framep may only affect DO_TRACE/DONT_TRACE return
    values, but we ignore them here anyway
  */
  switch(DoTrace(cs)) {
  case ENABLE_TRACE:
    framep->level|= TRACE_ON;
    break;
  case DISABLE_TRACE:
    framep->level&= ~TRACE_ON;
    break;
  }
}

#define fflags(cs) cs->stack->out_file ? ListFlags(cs->stack->functions) : TRACE_ON;

void FixTraceFlags(uint old_fflags, CODE_STATE *cs)
{
  const char *func;
  uint new_fflags, traceon, level;
  struct _db_stack_frame_ *framep;

  /*
    first (a.k.a. safety) check:
    if we haven't started tracing yet, no call stack at all - we're safe.
  */
  framep=cs->framep;
  if (framep == 0)
    return;

  /*
    Ok, the tracing has started, call stack isn't empty.

    second check: does the new list have a SUBDIR rule ?
  */
  new_fflags=fflags(cs);
  if (new_fflags & SUBDIR)
    goto yuck;

  /*
    Ok, new list doesn't use SUBDIR.

    third check: we do NOT need to re-scan if
    neither old nor new lists used SUBDIR flag and if a default behavior
    (whether an unlisted function is traced) hasn't changed.
    Default behavior depends on whether there're INCLUDE elements in the list.
  */
  if (!(old_fflags & SUBDIR) && !((new_fflags^old_fflags) & INCLUDE))
    return;

  /*
    Ok, old list may've used SUBDIR, or defaults could've changed.

    fourth check: are we inside a currently active SUBDIR rule ?
    go up the call stack, if TRACE_ON flag ever changes its value - we are.
  */
  for (traceon=framep->level; framep; framep=framep->prev)
    if ((traceon ^ framep->level) & TRACE_ON)
      goto yuck;

  /*
    Ok, TRACE_ON flag doesn't change in the call stack.

    fifth check: but is the top-most value equal to a default one ?
  */
  if (((traceon & TRACE_ON) != 0) == ((new_fflags & INCLUDE) == 0))
    return;

yuck:
  /*
    Yuck! function list was changed, and one of the currently active rules
    was possibly affected. For example, a tracing could've been enabled or
    disabled for a function somewhere up the call stack.
    To react correctly, we must go up the call stack all the way to
    the top and re-match rules to set TRACE_ON bit correctly.

    We must traverse the stack forwards, not backwards.
    That's what a recursive helper is doing.
    It'll destroy two CODE_STATE fields, save them now.
  */
  func= cs->func;
  level= cs->level;
  FixTraceFlags_helper(cs, func, cs->framep);
  /* now we only need to restore CODE_STATE fields, and we're done */
  cs->func= func;
  cs->level= level;
}

/*
 *  FUNCTION
 *
 *      _db_set_       set current debugger settings
 *
 *  SYNOPSIS
 *
 *      VOID _db_set_(control)
 *      char *control;
 *
 *  DESCRIPTION
 *
 *      Given pointer to a debug control string in "control",
 *      parses the control string, and sets up a current debug
 *      settings. Pushes a new debug settings if the current is
 *      set to the initial debugger settings.
 *
 */

void _db_set_(const char *control)
{
  CODE_STATE *cs;
  uint old_fflags;
  get_code_state_or_return;

  read_lock_stack(cs);
  old_fflags=fflags(cs);
  unlock_stack(cs);

  if (cs->stack == &init_settings)
    PushState(cs);

  if (DbugParse(cs, control))
  {
    read_lock_stack(cs);
    FixTraceFlags(old_fflags, cs);
    unlock_stack(cs);
  }
}

/*
 *  FUNCTION
 *
 *      _db_push_       push current debugger settings and set up new one
 *
 *  SYNOPSIS
 *
 *      VOID _db_push_(control)
 *      char *control;
 *
 *  DESCRIPTION
 *
 *      Given pointer to a debug control string in "control", pushes
 *      the current debug settings, parses the control string, and sets
 *      up a new debug settings with DbugParse()
 *
 */

void _db_push_(const char *control)
{
  CODE_STATE *cs;
  uint old_fflags;
  get_code_state_or_return;

  read_lock_stack(cs);
  old_fflags=fflags(cs);
  unlock_stack(cs);

  PushState(cs);

  if (DbugParse(cs, control))
  {
    read_lock_stack(cs);
    FixTraceFlags(old_fflags, cs);
    unlock_stack(cs);
  }
}


/**
  Returns TRUE if session-local settings have been set.
*/

int _db_is_pushed_()
{
  CODE_STATE *cs= NULL;
  get_code_state_or_return FALSE;
  return (cs->stack != &init_settings);
}

/*
 *  FUNCTION
 *
 *      _db_set_init_       set initial debugger settings
 *
 *  SYNOPSIS
 *
 *      VOID _db_set_init_(control)
 *      char *control;
 *
 *  DESCRIPTION
 *      see _db_set_
 *
 */

void _db_set_init_(const char *control)
{
  CODE_STATE tmp_cs;
  memset(&tmp_cs, 0, sizeof(tmp_cs));
  tmp_cs.stack= &init_settings;
  tmp_cs.process= db_process ? db_process : "dbug";
  DbugParse(&tmp_cs, control);
}

/*
 *  FUNCTION
 *
 *      _db_pop_    pop the debug stack
 *
 *  DESCRIPTION
 *
 *      Pops the debug stack, returning the debug settings to its
 *      condition prior to the most recent _db_push_ invocation.
 *      Note that the pop will fail if it would remove the last
 *      valid settings from the stack.  This prevents user errors
 *      in the push/pop sequence from screwing up the debugger.
 *      Maybe there should be some kind of warning printed if the
 *      user tries to pop too many states.
 *
 */

void _db_pop_()
{
  struct settings *discard;
  uint old_fflags;
  CODE_STATE *cs;

  get_code_state_or_return;

  discard= cs->stack;
  if (discard != &init_settings)
  {
    read_lock_stack(cs);
    old_fflags=fflags(cs);
    unlock_stack(cs);

    cs->stack= discard->next;
    FreeState(cs, discard, 1);

    read_lock_stack(cs);
    FixTraceFlags(old_fflags, cs);
    unlock_stack(cs);
  }
}

/*
 *  FUNCTION
 *
 *      _db_explain_    generates 'control' string for the current settings
 *
 *  RETURN
 *      0 - ok
 *      1  - buffer too short, output truncated
 *
 */

/* helper macros */
#define char_to_buf(C)    do {                  \
        *buf++=(C);                             \
        if (buf >= end) goto overflow;          \
      } while (0)
#define str_to_buf(S)    do {                   \
        char_to_buf(',');                       \
        buf=my_stpnmov(buf, (S), end-buf);      \
        if (buf >= end) goto overflow;          \
      } while (0)
#define list_to_buf(l, f)  do {                 \
        struct link *listp=(l);                 \
        while (listp)                           \
        {                                       \
          if (listp->flags & (f))               \
          {                                     \
            str_to_buf(listp->str);             \
            if (listp->flags & SUBDIR)          \
              char_to_buf('/');                 \
          }                                     \
          listp=listp->next_link;               \
        }                                       \
      } while (0)
#define int_to_buf(i)  do {                     \
        char b[50];                             \
        int10_to_str((i), b, 10);               \
        str_to_buf(b);                          \
      } while (0)
#define colon_to_buf   do {                     \
        if (buf != start) char_to_buf(':');     \
      } while(0)
#define op_int_to_buf(C, val, def) do {         \
        if ((val) != (def))                     \
        {                                       \
          colon_to_buf;                         \
          char_to_buf((C));                     \
          int_to_buf(val);                      \
        }                                       \
      } while (0)
#define op_intf_to_buf(C, val, def, cond) do {  \
        if ((cond))                             \
        {                                       \
          colon_to_buf;                         \
          char_to_buf((C));                     \
          if ((val) != (def)) int_to_buf(val);  \
        }                                       \
      } while (0)
#define op_str_to_buf(C, val, cond) do {        \
        if ((cond))                             \
        {                                       \
          char *s=(val);                        \
          colon_to_buf;                         \
          char_to_buf((C));                     \
          if (*s) str_to_buf(s);                \
        }                                       \
      } while (0)
#define op_list_to_buf(C, val, cond) do {       \
        if ((cond))                             \
        {                                       \
          int f=ListFlags(val);                 \
          colon_to_buf;                         \
          char_to_buf((C));                     \
          if (f & INCLUDE)                      \
            list_to_buf(val, INCLUDE);          \
          if (f & EXCLUDE)                      \
          {                                     \
            colon_to_buf;                       \
            char_to_buf('-');                   \
            char_to_buf((C));                   \
            list_to_buf(val, EXCLUDE);          \
          }                                     \
        }                                       \
      } while (0)
#define op_bool_to_buf(C, cond) do {            \
        if ((cond))                             \
        {                                       \
          colon_to_buf;                         \
          char_to_buf((C));                     \
        }                                       \
      } while (0)

int _db_explain_ (CODE_STATE *cs, char *buf, size_t len)
{
  char *start=buf, *end=buf+len-4;

  get_code_state_if_not_set_or_return *buf=0;

  read_lock_stack(cs);

  op_list_to_buf('d', cs->stack->keywords, DEBUGGING);
  op_int_to_buf ('D', cs->stack->delay, 0);
  op_list_to_buf('f', cs->stack->functions, cs->stack->functions);
  op_bool_to_buf('F', cs->stack->flags & FILE_ON);
  op_bool_to_buf('i', cs->stack->flags & PID_ON);
  op_list_to_buf('g', cs->stack->p_functions, PROFILING);
  op_bool_to_buf('L', cs->stack->flags & LINE_ON);
  op_bool_to_buf('n', cs->stack->flags & DEPTH_ON);
  op_bool_to_buf('N', cs->stack->flags & NUMBER_ON);
  op_str_to_buf(
    ((cs->stack->flags & FLUSH_ON_WRITE ? 0 : 32) |
     (cs->stack->flags & OPEN_APPEND ? 'A' : 'O')),
    cs->stack->name, cs->stack->out_file != stderr);
  op_list_to_buf('p', cs->stack->processes, cs->stack->processes);
  op_bool_to_buf('P', cs->stack->flags & PROCESS_ON);
  op_bool_to_buf('r', cs->stack->sub_level != 0);
  op_intf_to_buf('t', cs->stack->maxdepth, MAXDEPTH, TRACING);
  op_bool_to_buf('T', cs->stack->flags & TIMESTAMP_ON);

  unlock_stack(cs);

  *buf= '\0';
  return 0;

overflow:
  *end++= '.';
  *end++= '.';
  *end++= '.';
  *end=   '\0';

  unlock_stack(cs);
  return 1;
}

#undef char_to_buf
#undef str_to_buf
#undef list_to_buf
#undef int_to_buf
#undef colon_to_buf
#undef op_int_to_buf
#undef op_intf_to_buf
#undef op_str_to_buf
#undef op_list_to_buf
#undef op_bool_to_buf

/*
 *  FUNCTION
 *
 *      _db_explain_init_       explain initial debugger settings
 *
 *  DESCRIPTION
 *      see _db_explain_
 */

int _db_explain_init_(char *buf, size_t len)
{
  CODE_STATE cs;
  memset(&cs, 0, sizeof(cs));
  cs.stack=&init_settings;
  return _db_explain_(&cs, buf, len);
}

/*
 *  FUNCTION
 *
 *      _db_enter_    process entry point to user function
 *
 *  SYNOPSIS
 *
 *      VOID _db_enter_(_func_, _file_, _line_, _stack_frame_)
 *      char *_func_;           points to current function name
 *      char *_file_;           points to current file name
 *      int _line_;             called from source line number
 *      struct _db_stack_frame_ allocated on the caller's stack
 *
 *  DESCRIPTION
 *
 *      Called at the beginning of each user function to tell
 *      the debugger that a new function has been entered.
 *      Note that the pointers to the previous user function
 *      name and previous user file name are stored on the
 *      caller's stack (this is why the ENTER macro must be
 *      the first "executable" code in a function, since it
 *      allocates these storage locations).  The previous nesting
 *      level is also stored on the callers stack for internal
 *      self consistency checks.
 *
 *      Also prints a trace line if tracing is enabled and
 *      increments the current function nesting depth.
 *
 *      Note that this mechanism allows the debugger to know
 *      what the current user function is at all times, without
 *      maintaining an internal stack for the function names.
 *
 */

void _db_enter_(const char *_func_, const char *_file_,
                uint _line_, struct _db_stack_frame_ *_stack_frame_)
{
  int save_errno;
  CODE_STATE *cs;
  if (!((cs=code_state())))
  {
    _stack_frame_->level= 0; /* Set to avoid valgrind warnings if dbug is enabled later */
    _stack_frame_->prev= 0;
    return;
  }
  save_errno= errno;

  read_lock_stack(cs);

  _stack_frame_->func= cs->func;
  _stack_frame_->file= cs->file;
  cs->func=  _func_;
  cs->file=  _file_;
  _stack_frame_->prev= cs->framep;
  _stack_frame_->level= ++cs->level | framep_trace_flag(cs, cs->framep);
  cs->framep= _stack_frame_;

  switch (DoTrace(cs)) {
  case ENABLE_TRACE:
    cs->framep->level|= TRACE_ON;
    if (!TRACING) break;
    /* fall through */
  case DO_TRACE:
    if (TRACING)
    {
      if (!cs->locked)
        native_mutex_lock(&THR_LOCK_dbug);
      DoPrefix(cs, _line_);
      Indent(cs, cs->level);
      (void) fprintf(cs->stack->out_file, ">%s\n", cs->func);
      DbugFlush(cs);                       /* This does a unlock */
    }
    break;
  case DISABLE_TRACE:
    cs->framep->level&= ~TRACE_ON;
    /* fall through */
  case DONT_TRACE:
    break;
  }
  errno=save_errno;

  unlock_stack(cs);
}

/*
 *  FUNCTION
 *
 *      _db_return_    process exit from user function
 *
 *  SYNOPSIS
 *
 *      VOID _db_return_(_line_, _stack_frame_)
 *      int _line_;             current source line number
 *      struct _db_stack_frame_ allocated on the caller's stack
 *
 *  DESCRIPTION
 *
 *      Called just before user function executes an explicit or implicit
 *      return.  Prints a trace line if trace is enabled, decrements
 *      the current nesting level, and restores the current function and
 *      file names from the defunct function's stack.
 *
 */

void _db_return_(uint _line_, struct _db_stack_frame_ *_stack_frame_)
{
  int save_errno=errno;
  uint _slevel_= _stack_frame_->level & ~TRACE_ON;
  CODE_STATE *cs;
  get_code_state_or_return;

  if (cs->framep != _stack_frame_)
  {
    char buf[512];
    my_snprintf(buf, sizeof(buf), ERR_MISSING_RETURN, cs->func);
    DbugExit(buf);
  }

  read_lock_stack(cs);

  if (DoTrace(cs) & DO_TRACE)
  {
    if (TRACING)
    {
      if (!cs->locked)
        native_mutex_lock(&THR_LOCK_dbug);
      DoPrefix(cs, _line_);
      Indent(cs, cs->level);
      (void) fprintf(cs->stack->out_file, "<%s %u\n", cs->func, _line_);
      DbugFlush(cs);
    }
  }
  /*
    Check to not set level < 0. This can happen if DBUG was disabled when
    function was entered and enabled in function.
  */
  cs->level= _slevel_ != 0 ? _slevel_ - 1 : 0;
  cs->func= _stack_frame_->func;
  cs->file= _stack_frame_->file;
  if (cs->framep != NULL)
    cs->framep= cs->framep->prev;
  errno=save_errno;

  unlock_stack(cs);
}


/*
 *  FUNCTION
 *
 *      _db_pargs_    log arguments for subsequent use by _db_doprnt_()
 *
 *  SYNOPSIS
 *
 *      VOID _db_pargs_(_line_, keyword)
 *      int _line_;
 *      char *keyword;
 *
 *  DESCRIPTION
 *
 *      The new universal printing macro DBUG_PRINT, which replaces
 *      all forms of the DBUG_N macros, needs two calls to runtime
 *      support routines.  The first, this function, remembers arguments
 *      that are used by the subsequent call to _db_doprnt_().
 *
 */

void _db_pargs_(uint _line_, const char *keyword)
{
  CODE_STATE *cs;
  get_code_state_or_return;
  cs->u_line= _line_;
  cs->u_keyword= keyword;
}


/*
 *  FUNCTION
 *
 *    _db_enabled_    check if debug is enabled for the keyword used in
 *    DBUG_PRINT
 *
 *  SYNOPSIS
 *
 *    int _db_enabled_();
 *
 *  DESCRIPTION
 *
 *    The function checks if the debug output is to be enabled for the keyword
 *    specified in DBUG_PRINT macro. _db_doprnt_ will be called only if this
 *    function evaluates to 1.
 */

int _db_enabled_()
{
  CODE_STATE *cs;

  get_code_state_or_return 0;

  if (! DEBUGGING)
    return 0;

  if (_db_keyword_(cs, cs->u_keyword, 0))
    return 1;

  return 0;
}

/*
 *  FUNCTION
 *
 *      _db_doprnt_    handle print of debug lines
 *
 *  SYNOPSIS
 *
 *      VOID _db_doprnt_(format, va_alist)
 *      char *format;
 *      va_dcl;
 *
 *  DESCRIPTION
 *
 *      This function handles the printing of the arguments via the format
 *      string.  The line number of the DBUG macro in the source is found in
 *      u_line.
 *
 *      Note that the format string SHOULD NOT include a terminating
 *      newline, this is supplied automatically.
 *
 */

#include <stdarg.h>

void _db_doprnt_(const char *format,...)
{
  va_list args;
  CODE_STATE *cs;
  int save_errno;

  get_code_state_or_return;

  /* Dirty read, for DBUG_PRINT() performance. */
  if (! DEBUGGING)
    return;

  va_start(args,format);
  read_lock_stack(cs);

  save_errno=errno;
  if (!cs->locked)
    native_mutex_lock(&THR_LOCK_dbug);
  DoPrefix(cs, cs->u_line);
  if (TRACING)
    Indent(cs, cs->level + 1);
  else
    (void) fprintf(cs->stack->out_file, "%s: ", cs->func);
  (void) fprintf(cs->stack->out_file, "%s: ", cs->u_keyword);
  DbugVfprintf(cs->stack->out_file, format, args);
  DbugFlush(cs);
  errno=save_errno;

  unlock_stack(cs);
  va_end(args);
}


/*
 *  FUNCTION
 *
 *      _db_doputs_    handle print of debug lines
 *
 *  SYNOPSIS
 *
 *      VOID _db_doputs_(const char* log)
 *      const char *log;
 *
 *  DESCRIPTION
 *
 *      This function handles the printing of the argument via the log
 *      string.  The line number of the DBUG macro in the source is found in
 *      u_line.
 *
 *      Note that the log string SHOULD NOT include a terminating
 *      newline, this is supplied automatically.
 */
void _db_doputs_(const char *log)
{
  CODE_STATE *cs;
  int save_errno;

  get_code_state_or_return;

  /* Dirty read, for DBUG_PUTS() performance. */
  if (! DEBUGGING)
    return;

  read_lock_stack(cs);

  save_errno= errno;
  if (!cs->locked)
    native_mutex_lock(&THR_LOCK_dbug);
  DoPrefix(cs, cs->u_line);
  if (TRACING)
    Indent(cs, cs->level + 1);
  else
    (void) fprintf(cs->stack->out_file, "%s: ", cs->func);
  (void) fprintf(cs->stack->out_file, "%s: ", cs->u_keyword);
  fprintf(cs->stack->out_file, "%s\n", log);
  DbugFlush(cs);
  errno= save_errno;

  unlock_stack(cs);
}


/*
 * This function is intended as a
 * vfprintf clone with consistent, platform independent output for
 * problematic formats like %p, %zd and %lld.
 */
static void DbugVfprintf(FILE *stream, const char* format, va_list args)
{
  char cvtbuf[1024];
  (void) my_vsnprintf(cvtbuf, sizeof(cvtbuf), format, args);
  (void) fprintf(stream, "%s\n", cvtbuf);
}

/*
 *  FUNCTION
 *
 *            _db_dump_    dump a string in hex
 *
 *  SYNOPSIS
 *
 *            void _db_dump_(_line_,keyword,memory,length)
 *            int _line_;               current source line number
 *            char *keyword;
 *            char *memory;             Memory to print
 *            int length;               Bytes to print
 *
 *  DESCRIPTION
 *  Dump N characters in a binary array.
 *  Is used to examine corrupted memory or arrays.
 */

void _db_dump_(uint _line_, const char *keyword,
               const unsigned char *memory, size_t length)
{
  int pos;
  CODE_STATE *cs;
  get_code_state_or_return;

  /* Dirty read, for DBUG_DUMP() performance. */
  if (! DEBUGGING)
    return;

  read_lock_stack(cs);

  if (_db_keyword_(cs, keyword, 0))
  {
    if (!cs->locked)
      native_mutex_lock(&THR_LOCK_dbug);
    DoPrefix(cs, _line_);
    if (TRACING)
    {
      Indent(cs, cs->level + 1);
      pos= MY_MIN(MY_MAX(cs->level-cs->stack->sub_level,0)*INDENT,80);
    }
    else
    {
      fprintf(cs->stack->out_file, "%s: ", cs->func);
    }
    (void) fprintf(cs->stack->out_file, "%s: Memory: 0x%lx  Bytes: (%ld)\n",
            keyword, (ulong) memory, (long) length);

    pos=0;
    while (length-- > 0)
    {
      uint tmp= *((unsigned char*) memory++);
      if ((pos+=3) >= 80)
      {
        fputc('\n',cs->stack->out_file);
        pos=3;
      }
      fputc(_dig_vec_upper[((tmp >> 4) & 15)], cs->stack->out_file);
      fputc(_dig_vec_upper[tmp & 15], cs->stack->out_file);
      fputc(' ',cs->stack->out_file);
    }
    (void) fputc('\n',cs->stack->out_file);
    DbugFlush(cs);
  }

  unlock_stack(cs);
}


/*
  Return true if the character pointer to by ptr is either
  comma or a whitespace character.

  @param    ptr     pointer to char
  @return           1 if the character is whitespace or
                    comma
*/

static inline int isseparator(const char* ptr)
{
  return (*ptr ==',' || isspace(*ptr));
}


/*
 *  FUNCTION
 *
 *      ListAddDel    modify the list according to debug control string
 *
 *  DESCRIPTION
 *
 *      Given pointer to a comma separated list of strings in "cltp",
 *      parses the list, and modifies "listp", returning a pointer
 *      to the new list.
 *
 *      The mode of operation is defined by "todo" parameter.
 *
 *      If it is INCLUDE, elements (strings from "cltp") are added to the
 *      list, they will have INCLUDE flag set. If the list already contains
 *      the string in question, new element is not added, but a flag of
 *      the existing element is adjusted (INCLUDE bit is set, EXCLUDE bit
 *      is removed).
 *
 *      If it is EXCLUDE, elements are added to the list with the EXCLUDE
 *      flag set. If the list already contains the string in question,
 *      it is removed, new element is not added.
 */

static struct link *ListAddDel(struct link *head, const char *ctlp,
                               const char *end, int todo)
{
  const char *start;
  struct link **cur;
  size_t len;
  int subdir;

  ctlp--;
next:
  while (++ctlp < end)
  {
    // skip whitespace or comma
    while (isseparator(ctlp))
      ctlp++;
    start= ctlp;
    subdir=0;
    while (ctlp < end && !isseparator(ctlp))
      ctlp++;
    len=ctlp-start;
    if (start[len-1] == '/')
    {
      len--;
      subdir=SUBDIR;
    }
    if (len == 0) continue;
    for (cur=&head; *cur; cur=&((*cur)->next_link))
    {
      if (len == strlen((*cur)->str) && !strncmp((*cur)->str, start, len))
      {
        if ((*cur)->flags & todo)  /* same action ? */
          (*cur)->flags|= subdir;  /* just merge the SUBDIR flag */
        else if (todo == EXCLUDE)
        {
          struct link *delme=*cur;
          *cur=(*cur)->next_link;
          free((void*) delme);
        }
        else
        {
          (*cur)->flags&=~(EXCLUDE | SUBDIR);
          (*cur)->flags|=INCLUDE | subdir;
        }
        goto next;
      }
    }
    *cur= (struct link *) DbugMalloc(sizeof(struct link)+len);
    memcpy((*cur)->str, start, len);
    (*cur)->str[len]=0;
    (*cur)->flags=todo | subdir;
    (*cur)->next_link=0;
  }
  return head;
}

/*
 *  FUNCTION
 *
 *      ListCopy    make a copy of the list
 *
 *  SYNOPSIS
 *
 *      static struct link *ListCopy(orig)
 *      struct link *orig;
 *
 *  DESCRIPTION
 *
 *      Given pointer to list, which contains a copy of every element from
 *      the original list.
 *
 *      the orig pointer can be NULL
 *
 *      Note that since each link is added at the head of the list,
 *      the final list will be in "reverse order", which is not
 *      significant for our usage here.
 *
 */

static struct link *ListCopy(struct link *orig)
{
  struct link *new_malloc;
  struct link *head;
  size_t len;

  head= NULL;
  while (orig != NULL)
  {
    len= strlen(orig->str);
    new_malloc= (struct link *) DbugMalloc(sizeof(struct link)+len);
    memcpy(new_malloc->str, orig->str, len);
    new_malloc->str[len]= 0;
    new_malloc->flags=orig->flags;
    new_malloc->next_link= head;
    head= new_malloc;
    orig= orig->next_link;
  }
  return head;
}

/*
 *  FUNCTION
 *
 *      InList    test a given string for member of a given list
 *
 *  DESCRIPTION
 *
 *      Tests the string pointed to by "cp" to determine if it is in
 *      the list pointed to by "linkp".  Linkp points to the first
 *      link in the list.  If linkp is NULL or contains only EXCLUDE
 *      elements then the string is treated as if it is in the list.
 *      This may seem rather strange at first but leads to the desired
 *      operation if no list is given.  The net effect is that all
 *      strings will be accepted when there is no list, and when there
 *      is a list, only those strings in the list will be accepted.
 *
 *  RETURN
 *      combination of SUBDIR, INCLUDE, EXCLUDE, MATCHED flags
 *
 */

static int InList(struct link *linkp, const char *cp)
{
  int result;

  for (result=MATCHED; linkp != NULL; linkp= linkp->next_link)
  {
    if (!fnmatch(linkp->str, cp, 0))
      return linkp->flags;
    if (!(linkp->flags & EXCLUDE))
      result=NOT_MATCHED;
    if (linkp->flags & SUBDIR)
      result|=SUBDIR;
  }
  return result;
}

/*
 *  FUNCTION
 *
 *      ListFlags    returns aggregated list flags (ORed over all elements)
 *
 */

static uint ListFlags(struct link *linkp)
{
  uint f;
  for (f=0; linkp != NULL; linkp= linkp->next_link)
    f|= linkp->flags;
  return f;
}

/*
 *  FUNCTION
 *
 *      PushState    push current settings onto stack and set up new one
 *
 *  SYNOPSIS
 *
 *      static VOID PushState()
 *
 *  DESCRIPTION
 *
 *      Pushes the current settings on the settings stack, and creates
 *      a new settings. The new settings is NOT initialized
 *
 *      The settings stack is a linked list of settings, with the new
 *      settings added at the head.  This allows the stack to grow
 *      to the limits of memory if necessary.
 *
 */

static void PushState(CODE_STATE *cs)
{
  struct settings *new_malloc;

  new_malloc= (struct settings *) DbugMalloc(sizeof(struct settings));
  memset(new_malloc, 0, sizeof(struct settings));
  new_malloc->next= cs->stack;
  cs->stack= new_malloc;
}

/*
 *  FUNCTION
 *
 *	FreeState    Free memory associated with a struct state.
 *
 *  SYNOPSIS
 *
 *	static void FreeState (state)
 *	struct state *state;
 *      int free_state;
 *
 *  DESCRIPTION
 *
 *	Deallocates the memory allocated for various information in a
 *	state. If free_state is set, also free 'state'
 *
 */
static void FreeState(CODE_STATE *cs, struct settings *state, int free_state)
{
  if (!is_shared(state, keywords))
    FreeList(state->keywords);
  if (!is_shared(state, functions))
    FreeList(state->functions);
  if (!is_shared(state, processes))
    FreeList(state->processes);
  if (!is_shared(state, p_functions))
    FreeList(state->p_functions);

  if (!is_shared(state, out_file))
    DBUGCloseFile(cs, state->out_file);
  else
    (void) fflush(state->out_file);

  if (!is_shared(state, prof_file))
    DBUGCloseFile(cs, state->prof_file);
  else
    (void) fflush(state->prof_file);

  if (free_state)
    free((void*) state);
}


/*
 *  FUNCTION
 *
 *	_db_end_    End debugging, freeing state stack memory.
 *
 *  SYNOPSIS
 *
 *	static VOID _db_end_ ()
 *
 *  DESCRIPTION
 *
 *	Ends debugging, de-allocating the memory allocated to the
 *	state stack.
 *
 *	To be called at the very end of the program.
 *
 */
void _db_end_()
{
  struct settings *discard;
  static struct settings tmp;
  CODE_STATE *cs;
  /*
    Set _dbug_on_ to be able to do full reset even when DEBUGGER_OFF was
    called after dbug was initialized
  */
  _dbug_on_= 1;
  get_code_state_or_return;

  /*
    The caller may have missed a DBUG_UNLOCK_FILE,
    we are breaking this lock to enforce DBUG_END can proceed.
  */
  if (cs->locked)
  {
    fprintf(stderr, ERR_MISSING_UNLOCK, "(unknown)");
    cs->locked= 0;
    native_mutex_unlock(&THR_LOCK_dbug);
  }

  while ((discard= cs->stack))
  {
    if (discard == &init_settings)
      break;
    cs->stack= discard->next;
    FreeState(cs, discard, 1);
  }

  native_rw_wrlock(&THR_LOCK_init_settings);
  tmp= init_settings;
  init_settings.flags=    OPEN_APPEND;
  init_settings.out_file= stderr;
  init_settings.prof_file= stderr;
  init_settings.maxdepth= 0;
  init_settings.delay= 0;
  init_settings.sub_level= 0;
  init_settings.functions= 0;
  init_settings.p_functions= 0;
  init_settings.keywords= 0;
  init_settings.processes= 0;
  native_rw_unlock(&THR_LOCK_init_settings);
  FreeState(cs, &tmp, 0);
}


/*
 *  FUNCTION
 *
 *      DoTrace    check to see if tracing is current enabled
 *
 *  DESCRIPTION
 *
 *      Checks to see if dbug in this function is enabled based on
 *      whether the maximum trace depth has been reached, the current
 *      function is selected, and the current process is selected.
 *
 */

static int DoTrace(CODE_STATE *cs)
{
  if ((cs->stack->maxdepth == 0 || cs->level <= cs->stack->maxdepth) &&
      InList(cs->stack->processes, cs->process) & (MATCHED|INCLUDE))
    switch(InList(cs->stack->functions, cs->func)) {
    case INCLUDE|SUBDIR:  return ENABLE_TRACE;
    case INCLUDE:         return DO_TRACE;
    case MATCHED|SUBDIR:
    case NOT_MATCHED|SUBDIR:
    case MATCHED:         return framep_trace_flag(cs, cs->framep) ?
                                           DO_TRACE : DONT_TRACE;
    case EXCLUDE:
    case NOT_MATCHED:     return DONT_TRACE;
    case EXCLUDE|SUBDIR:  return DISABLE_TRACE;
    }
  return DONT_TRACE;
}

FILE *_db_fp_(void)
{
  CODE_STATE *cs;
  get_code_state_or_return NULL;
  return cs->stack->out_file;
}

/*
 *  FUNCTION
 *
 *      _db_keyword_    test keyword for member of keyword list
 *
 *  DESCRIPTION
 *
 *      Test a keyword to determine if it is in the currently active
 *      keyword list.  If strict=0, a keyword is accepted
 *      if the list is null, otherwise it must match one of the list
 *      members.  When debugging is not on, no keywords are accepted.
 *      After the maximum trace level is exceeded, no keywords are
 *      accepted (this behavior subject to change).  Additionally,
 *      the current function and process must be accepted based on
 *      their respective lists.
 *
 *      Returns TRUE if keyword accepted, FALSE otherwise.
 *
 */

BOOLEAN _db_keyword_(CODE_STATE *cs, const char *keyword, int strict)
{
  BOOLEAN result;
  get_code_state_if_not_set_or_return FALSE;

  /* Dirty read, for DBUG_EXECUTE(), DBUG_EXECUTE_IF() ... performance. */
  if (! DEBUGGING)
    return FALSE;

  read_lock_stack(cs);

  strict=strict ? INCLUDE : INCLUDE|MATCHED;
  result= DoTrace(cs) & DO_TRACE &&
          InList(cs->stack->keywords, keyword) & strict;

  unlock_stack(cs);

  return result;
}

/*
 *  FUNCTION
 *
 *      Indent    indent a line to the given indentation level
 *
 *  SYNOPSIS
 *
 *      static VOID Indent(indent)
 *      int indent;
 *
 *  DESCRIPTION
 *
 *      Indent a line to the given level.  Note that this is
 *      a simple minded but portable implementation.
 *      There are better ways.
 *
 *      Also, the indent must be scaled by the compile time option
 *      of character positions per nesting level.
 *
 */

static void Indent(CODE_STATE *cs, int indent)
{
  int count;

  indent= MY_MAX(indent-1-cs->stack->sub_level,0)*INDENT;
  for (count= 0; count < indent ; count++)
  {
    if ((count % INDENT) == 0)
      fputc('|',cs->stack->out_file);
    else
      fputc(' ',cs->stack->out_file);
  }
}


/*
 *  FUNCTION
 *
 *      FreeList    free all memory associated with a linked list
 *
 *  SYNOPSIS
 *
 *      static VOID FreeList(linkp)
 *      struct link *linkp;
 *
 *  DESCRIPTION
 *
 *      Given pointer to the head of a linked list, frees all
 *      memory held by the list and the members of the list.
 *
 */

static void FreeList(struct link *linkp)
{
  struct link *old;

  while (linkp != NULL)
  {
    old= linkp;
    linkp= linkp->next_link;
    free((void*) old);
  }
}


/*
 *  FUNCTION
 *
 *      DoPrefix    print debugger line prefix prior to indentation
 *
 *  SYNOPSIS
 *
 *      static VOID DoPrefix(_line_)
 *      int _line_;
 *
 *  DESCRIPTION
 *
 *      Print prefix common to all debugger output lines, prior to
 *      doing indentation if necessary.  Print such information as
 *      current process name, current source file name and line number,
 *      and current function nesting depth.
 *
 */

static void DoPrefix(CODE_STATE *cs, uint _line_)
{
  cs->lineno++;
  if (cs->stack->flags & PID_ON)
  {
    (void) fprintf(cs->stack->out_file, "T@%u: ", my_thread_var_id());
  }
  if (cs->stack->flags & NUMBER_ON)
    (void) fprintf(cs->stack->out_file, "%5d: ", cs->lineno);
  if (cs->stack->flags & TIMESTAMP_ON)
  {
#ifdef _WIN32
    /* FIXME This doesn't give microseconds as in Unix case, and the resolution is
       in system ticks, 10 ms intervals. See my_getsystime.c for high res */
    SYSTEMTIME loc_t;
    GetLocalTime(&loc_t);
    (void) fprintf (cs->stack->out_file,
                    /* "%04d-%02d-%02d " */
                    "%02d:%02d:%02d.%06d ",
                    /*tm_p->tm_year + 1900, tm_p->tm_mon + 1, tm_p->tm_mday,*/
                    loc_t.wHour, loc_t.wMinute, loc_t.wSecond, loc_t.wMilliseconds);
#else
    struct timeval tv;
    struct tm *tm_p;
    if (gettimeofday(&tv, NULL) != -1)
    {
      if ((tm_p= localtime((const time_t *)&tv.tv_sec)))
      {
        (void) fprintf (cs->stack->out_file,
                        /* "%04d-%02d-%02d " */
                        "%02d:%02d:%02d.%06d ",
                        /*tm_p->tm_year + 1900, tm_p->tm_mon + 1, tm_p->tm_mday,*/
                        tm_p->tm_hour, tm_p->tm_min, tm_p->tm_sec,
                        (int) (tv.tv_usec));
      }
    }
#endif
  }
  if (cs->stack->flags & PROCESS_ON)
    (void) fprintf(cs->stack->out_file, "%s: ", cs->process);
  if (cs->stack->flags & FILE_ON)
    (void) fprintf(cs->stack->out_file, "%14s: ", BaseName(cs->file));
  if (cs->stack->flags & LINE_ON)
    (void) fprintf(cs->stack->out_file, "%5d: ", _line_);
  if (cs->stack->flags & DEPTH_ON)
    (void) fprintf(cs->stack->out_file, "%4d: ", cs->level);
}


/*
 *  FUNCTION
 *
 *      DBUGOpenFile    open new output stream for debugger output
 *
 *  SYNOPSIS
 *
 *      static VOID DBUGOpenFile(name)
 *      char *name;
 *
 *  DESCRIPTION
 *
 *      Given name of a new file (or "-" for stdout) opens the file
 *      and sets the output stream to the new file.
 *
 */

static void DBUGOpenFile(CODE_STATE *cs,
                         const char *name,const char *end,int append)
{
  FILE *fp;

  if (name != NULL)
  {
    if (end)
    {
      size_t len=end-name;
      memcpy(cs->stack->name, name, len);
      cs->stack->name[len]=0;
    }
    else
    my_stpcpy(cs->stack->name,name);
    name=cs->stack->name;
    if (strcmp(name, "-") == 0)
    {
      cs->stack->out_file= stdout;
      cs->stack->flags |= FLUSH_ON_WRITE;
      cs->stack->name[0]=0;
    }
    else
    {
      if (!Writable(name))
      {
        (void) fprintf(stderr, ERR_OPEN, cs->process, name);
        perror("");
        fflush(stderr);
      }
      else
      {
        if (!(fp= fopen(name, append ? "a+" : "w")))
        {
          (void) fprintf(stderr, ERR_OPEN, cs->process, name);
          perror("");
          fflush(stderr);
        }
        else
        {
          cs->stack->out_file= fp;
        }
      }
    }
  }
}

/*
 *  FUNCTION
 *
 *      DBUGCloseFile    close the debug output stream
 *
 *  SYNOPSIS
 *
 *      static VOID DBUGCloseFile(fp)
 *      FILE *fp;
 *
 *  DESCRIPTION
 *
 *      Closes the debug output stream unless it is standard output
 *      or standard error.
 *
 */

static void DBUGCloseFile(CODE_STATE *cs, FILE *fp)
{
  if (fp != NULL && fp != stderr && fp != stdout && fclose(fp) == EOF)
  {
    native_mutex_lock(&THR_LOCK_dbug);
    (void) fprintf(cs->stack->out_file, ERR_CLOSE, cs->process);
    perror("");
    DbugFlush(cs);
  }
}


/*
 *  FUNCTION
 *
 *      DbugExit    print error message and exit
 *
 *  SYNOPSIS
 *
 *      static VOID DbugExit(why)
 *      char *why;
 *
 *  DESCRIPTION
 *
 *      Prints error message using current process name, the reason for
 *      aborting (typically out of memory), and exits with status 1.
 *      This should probably be changed to use a status code
 *      defined in the user's debugger include file.
 *
 */

static void DbugExit(const char *why)
{
  CODE_STATE *cs=code_state();
  (void) fprintf(stderr, ERR_ABORT, cs ? cs->process : "(null)", why);
  (void) fflush(stderr);
  DBUG_ABORT();
}


/*
 *  FUNCTION
 *
 *      DbugMalloc    allocate memory for debugger runtime support
 *
 *  SYNOPSIS
 *
 *      static long *DbugMalloc(size)
 *      int size;
 *
 *  DESCRIPTION
 *
 *      Allocate more memory for debugger runtime support functions.
 *      Failure to to allocate the requested number of bytes is
 *      immediately fatal to the current process.  This may be
 *      rather unfriendly behavior.  It might be better to simply
 *      print a warning message, freeze the current debugger cs,
 *      and continue execution.
 *
 */

static char *DbugMalloc(size_t size)
{
  char *new_malloc;

  if (!(new_malloc= (char*) malloc(size)))
    DbugExit("out of memory");
  return new_malloc;
}


/*
 *     strtok lookalike - splits on ':', magically handles ::, :\ and :/
 */

static const char *DbugStrTok(const char *s)
{
  while (s[0] && (s[0] != ':' ||
                  (s[1] == '\\' || s[1] == '/' || (s[1] == ':' && s++))))
    s++;
  return s;
}


/*
 *  FUNCTION
 *
 *      BaseName    strip leading pathname components from name
 *
 *  SYNOPSIS
 *
 *      static char *BaseName(pathname)
 *      char *pathname;
 *
 *  DESCRIPTION
 *
 *      Given pointer to a complete pathname, locates the base file
 *      name at the end of the pathname and returns a pointer to
 *      it.
 *
 */

static const char *BaseName(const char *pathname)
{
  const char *base;

  base= strrchr(pathname, FN_LIBCHAR);
  if (base++ == NullS)
    base= pathname;
  return base;
}


/*
 *  FUNCTION
 *
 *      Writable    test to see if a pathname is writable/creatable
 *
 *  SYNOPSIS
 *
 *      static BOOLEAN Writable(pathname)
 *      char *pathname;
 *
 *  DESCRIPTION
 *
 *      Because the debugger might be linked in with a program that
 *      runs with the set-uid-bit (suid) set, we have to be careful
 *      about opening a user named file for debug output.  This consists
 *      of checking the file for write access with the real user id,
 *      or checking the directory where the file will be created.
 *
 *      Returns TRUE if the user would normally be allowed write or
 *      create access to the named file.  Returns FALSE otherwise.
 *
 */


static BOOLEAN Writable(const char *pathname)
{
  BOOLEAN granted;
  char *lastslash;

  granted= FALSE;
  if (my_access(pathname, F_OK) == 0)
  {
    if (my_access(pathname, W_OK) == 0)
      granted= TRUE;
  }
  else
  {
    lastslash= strrchr(pathname, '/');
    if (lastslash != NULL)
      *lastslash= '\0';
    else
      pathname= ".";
    if (my_access(pathname, W_OK) == 0)
      granted= TRUE;
    if (lastslash != NULL)
      *lastslash= '/';
  }
  return granted;
}


/*
 *  FUNCTION
 *
 *      _db_setjmp_    save debugger environment
 *
 *  SYNOPSIS
 *
 *      VOID _db_setjmp_()
 *
 *  DESCRIPTION
 *
 *      Invoked as part of the user's DBUG_SETJMP macro to save
 *      the debugger environment in parallel with saving the user's
 *      environment.
 *
 */

EXPORT void _db_setjmp_()
{
  CODE_STATE *cs;
  get_code_state_or_return;

  cs->jmplevel= cs->level;
  cs->jmpfunc= cs->func;
  cs->jmpfile= cs->file;
}

/*
 *  FUNCTION
 *
 *      _db_longjmp_    restore previously saved debugger environment
 *
 *  SYNOPSIS
 *
 *      VOID _db_longjmp_()
 *
 *  DESCRIPTION
 *
 *      Invoked as part of the user's DBUG_LONGJMP macro to restore
 *      the debugger environment in parallel with restoring the user's
 *      previously saved environment.
 *
 */

EXPORT void _db_longjmp_()
{
  CODE_STATE *cs;
  get_code_state_or_return;

  cs->level= cs->jmplevel;
  if (cs->jmpfunc)
    cs->func= cs->jmpfunc;
  if (cs->jmpfile)
    cs->file= cs->jmpfile;
}

        /* flush dbug-stream, free mutex lock & wait delay */
        /* This is because some systems (MSDOS!!) dosn't flush fileheader */
        /* and dbug-file isn't readable after a system crash !! */

static void DbugFlush(CODE_STATE *cs)
{
  if (cs->stack->flags & FLUSH_ON_WRITE)
  {
    (void) fflush(cs->stack->out_file);
    if (cs->stack->delay)
      (void) Delay(cs->stack->delay);
  }
  if (!cs->locked)
    native_mutex_unlock(&THR_LOCK_dbug);
} /* DbugFlush */


/* For debugging */

void _db_flush_()
{
  CODE_STATE *cs= NULL;
  get_code_state_or_return;
  (void) fflush(cs->stack->out_file);
}


#ifndef _WIN32

#ifdef HAVE_GCOV
extern void __gcov_flush();
#endif

void _db_flush_gcov_()
{
#ifdef HAVE_GCOV
  // Gcov will assert() if we try to flush in parallel.
  native_mutex_lock(&THR_LOCK_gcov);
  __gcov_flush();
  native_mutex_unlock(&THR_LOCK_gcov);
#endif
}

void _db_suicide_()
{
  int retval;
  sigset_t new_mask;
  sigfillset(&new_mask);

#ifdef HAVE_GCOV
  fprintf(stderr, "Flushing gcov data\n");
  fflush(stderr);
  _db_flush_gcov_();
#endif

  fprintf(stderr, "SIGKILL myself\n");
  fflush(stderr);

  retval= kill(getpid(), SIGKILL);
  assert(retval == 0);
  retval= sigsuspend(&new_mask);
  fprintf(stderr, "sigsuspend returned %d errno %d \n", retval, errno);
  assert(FALSE); /* With full signal mask, we should never return here. */
}
#endif  /* ! _WIN32 */


void _db_lock_file_()
{
  CODE_STATE *cs;
  get_code_state_or_return;
  native_mutex_lock(&THR_LOCK_dbug);
  cs->locked=1;
}

void _db_unlock_file_()
{
  CODE_STATE *cs;
  get_code_state_or_return;
  cs->locked=0;
  native_mutex_unlock(&THR_LOCK_dbug);
}

const char* _db_get_func_(void)
{
  CODE_STATE *cs;
  get_code_state_or_return NULL;
  return cs->func;
}


#else

/*
 * Dummy function, workaround for MySQL bug#14420 related
 * build failure on a platform where linking with an empty
 * archive fails.
 *
 * This block can be removed as soon as a fix for bug#14420
 * is implemented.
 */
int i_am_a_dummy_function() {
       return 0;
}

#endif