strsignal.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 648 行 · 第 1/2 页

#ifndef HAVE_SYS_SIGLIST

  /* Now attempt to allocate the sys_siglist table, zero it out, and then
     initialize it from the statically initialized signal_table. */

  if (sys_siglist == NULL)
    {
      nbytes = num_signal_names * sizeof (char *);
      if ((sys_siglist = (const char **) malloc (nbytes)) != NULL)
	{
	  memset (sys_siglist, 0, nbytes);
	  sys_nsig = num_signal_names;
	  for (eip = signal_table; eip -> name != NULL; eip++)
	    {
	      sys_siglist[eip -> value] = eip -> msg;
	    }
	}
    }

#endif

}


/*

NAME

	signo_max -- return the max signo value

SYNOPSIS

	int signo_max ();

DESCRIPTION

	Returns the maximum signo value for which a corresponding symbolic
	name or message is available.  Note that in the case where
	we use the sys_siglist supplied by the system, it is possible for
	there to be more symbolic names than messages, or vice versa.
	In fact, the manual page for psignal(3b) explicitly warns that one
	should check the size of the table (NSIG) before indexing it,
	since new signal codes may be added to the system before they are
	added to the table.  Thus NSIG might be smaller than value
	implied by the largest signo value defined in <signal.h>.

	We return the maximum value that can be used to obtain a meaningful
	symbolic name or message.

*/

int
signo_max ()
{
  int maxsize;

  if (signal_names == NULL)
    {
      init_signal_tables ();
    }
  maxsize = MAX (sys_nsig, num_signal_names);
  return (maxsize - 1);
}


/*

NAME

	strsignal -- map a signal number to a signal message string

SYNOPSIS

	const char *strsignal (int signo)

DESCRIPTION

	Maps an signal number to an signal message string, the contents of
	which are implementation defined.  On systems which have the external
	variable sys_siglist, these strings will be the same as the ones used
	by psignal().

	If the supplied signal number is within the valid range of indices
	for the sys_siglist, but no message is available for the particular
	signal number, then returns the string "Signal NUM", where NUM is the
	signal number.

	If the supplied signal number is not a valid index into sys_siglist,
	returns NULL.

	The returned string is only guaranteed to be valid only until the
	next call to strsignal.

*/

#ifndef HAVE_STRSIGNAL

const char *
strsignal (signo)
  int signo;
{
  const char *msg;
  static char buf[32];

#ifndef HAVE_SYS_SIGLIST

  if (signal_names == NULL)
    {
      init_signal_tables ();
    }

#endif

  if ((signo < 0) || (signo >= sys_nsig))
    {
      /* Out of range, just return NULL */
      msg = NULL;
    }
  else if ((sys_siglist == NULL) || (sys_siglist[signo] == NULL))
    {
      /* In range, but no sys_siglist or no entry at this index. */
      sprintf (buf, "Signal %d", signo);
      msg = (const char *) buf;
    }
  else
    {
      /* In range, and a valid message.  Just return the message. */
      msg = (const char *) sys_siglist[signo];
    }
  
  return (msg);
}

#endif /* ! HAVE_STRSIGNAL */

/*

NAME

	strsigno -- map an signal number to a symbolic name string

SYNOPSIS

	const char *strsigno (int signo)

DESCRIPTION

	Given an signal number, returns a pointer to a string containing
	the symbolic name of that signal number, as found in <signal.h>.

	If the supplied signal number is within the valid range of indices
	for symbolic names, but no name is available for the particular
	signal number, then returns the string "Signal NUM", where NUM is
	the signal number.

	If the supplied signal number is not within the range of valid
	indices, then returns NULL.

BUGS

	The contents of the location pointed to are only guaranteed to be
	valid until the next call to strsigno.

*/

const char *
strsigno (signo)
  int signo;
{
  const char *name;
  static char buf[32];

  if (signal_names == NULL)
    {
      init_signal_tables ();
    }

  if ((signo < 0) || (signo >= num_signal_names))
    {
      /* Out of range, just return NULL */
      name = NULL;
    }
  else if ((signal_names == NULL) || (signal_names[signo] == NULL))
    {
      /* In range, but no signal_names or no entry at this index. */
      sprintf (buf, "Signal %d", signo);
      name = (const char *) buf;
    }
  else
    {
      /* In range, and a valid name.  Just return the name. */
      name = signal_names[signo];
    }

  return (name);
}


/*

NAME

	strtosigno -- map a symbolic signal name to a numeric value

SYNOPSIS

	int strtosigno (char *name)

DESCRIPTION

	Given the symbolic name of a signal, map it to a signal number.
	If no translation is found, returns 0.

*/

int
strtosigno (name)
     const char *name;
{
  int signo = 0;

  if (name != NULL)
    {
      if (signal_names == NULL)
	{
	  init_signal_tables ();
	}
      for (signo = 0; signo < num_signal_names; signo++)
	{
	  if ((signal_names[signo] != NULL) &&
	      (strcmp (name, signal_names[signo]) == 0))
	    {
	      break;
	    }
	}
      if (signo == num_signal_names)
	{
	  signo = 0;
	}
    }
  return (signo);
}


/*

NAME

	psignal -- print message about signal to stderr

SYNOPSIS

	void psignal (unsigned signo, char *message);

DESCRIPTION

	Print to the standard error the message, followed by a colon,
	followed by the description of the signal specified by signo,
	followed by a newline.
*/

#ifndef HAVE_PSIGNAL

void
psignal (signo, message)
  unsigned signo;
  char *message;
{
  if (signal_names == NULL)
    {
      init_signal_tables ();
    }
  if ((signo <= 0) || (signo >= sys_nsig))
    {
      fprintf (stderr, "%s: unknown signal\n", message);
    }
  else
    {
      fprintf (stderr, "%s: %s\n", message, sys_siglist[signo]);
    }
}

#endif	/* ! HAVE_PSIGNAL */


/* A simple little main that does nothing but print all the signal translations
   if MAIN is defined and this file is compiled and linked. */

#ifdef MAIN

#include <stdio.h>

int
main ()
{
  int signo;
  int maxsigno;
  const char *name;
  const char *msg;

  maxsigno = signo_max ();
  printf ("%d entries in names table.\n", num_signal_names);
  printf ("%d entries in messages table.\n", sys_nsig);
  printf ("%d is max useful index.\n", maxsigno);

  /* Keep printing values until we get to the end of *both* tables, not
     *either* table.  Note that knowing the maximum useful index does *not*
     relieve us of the responsibility of testing the return pointer for
     NULL. */

  for (signo = 0; signo <= maxsigno; signo++)
    {
      name = strsigno (signo);
      name = (name == NULL) ? "<NULL>" : name;
      msg = strsignal (signo);
      msg = (msg == NULL) ? "<NULL>" : msg;
      printf ("%-4d%-18s%s\n", signo, name, msg);
    }

  return 0;
}

#endif