string/strsignal.c

   1 /* Copyright (C) 1991, 94, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <signal.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <libintl.h>
  24 #include <bits/libc-lock.h>
  25
  26
  27 #ifndef HAVE_GNU_LD
  28 #define _sys_siglist    sys_siglist
  29 #endif
  30
  31 /* Defined in siglist.c.  */
  32 extern const char *const _sys_siglist[];
  33 static __libc_key_t key;
  34
  35 /* If nonzero the key allocation failed and we should better use a
  36    static buffer than fail.  */
  37 #define BUFFERSIZ       100
  38 static char local_buf[BUFFERSIZ];
  39 static char *static_buf;
  40
  41 /* Destructor for the thread-specific data.  */
  42 static void init (void);
  43 static void free_key_mem (void *mem);
  44 static char *getbuffer (void);
  45
  46
  47 /* Return a string describing the meaning of the signal number SIGNUM.  */
  48 char *
  49 strsignal (int signum)
  50 {
  51   __libc_once_define (static, once);
  52   const char *desc;
  53
  54   /* If we have not yet initialized the buffer do it now.  */
  55   __libc_once (once, init);
  56
  57   if (
  58 #ifdef SIGRTMIN
  59       (signum >= SIGRTMIN && signum <= SIGRTMAX) ||
  60 #endif
  61       signum < 0 || signum >= NSIG || (desc = _sys_siglist[signum]) == NULL)
  62     {
  63       char *buffer = getbuffer ();
  64       int len;
  65 #ifdef SIGRTMIN
  66       if (signum >= SIGRTMIN && signum <= SIGRTMAX)
  67         len = __snprintf (buffer, BUFFERSIZ - 1, _("Real-time signal %d"),
  68                           signum - SIGRTMIN);
  69       else
  70 #endif
  71         len = __snprintf (buffer, BUFFERSIZ - 1, _("Unknown signal %d"),
  72                           signum);
  73       if (len >= BUFFERSIZ)
  74         buffer = NULL;
  75       else
  76         buffer[len] = '\0';
  77
  78       return buffer;
  79     }
  80
  81   return (char *) _(desc);
  82 }
  83
  84
  85 /* Initialize buffer.  */
  86 static void
  87 init (void)
  88 {
  89   if (__libc_key_create (&key, free_key_mem))
  90     /* Creating the key failed.  This means something really went
  91        wrong.  In any case use a static buffer which is better than
  92        nothing.  */
  93     static_buf = local_buf;
  94 }
  95
  96
  97 /* Free the thread specific data, this is done if a thread terminates.  */
  98 static void
  99 free_key_mem (void *mem)
 100 {
 101   free (mem);
 102   __libc_setspecific (key, NULL);
 103 }
 104
 105
 106 /* Return the buffer to be used.  */
 107 static char *
 108 getbuffer (void)
 109 {
 110   char *result;
 111
 112   if (static_buf != NULL)
 113     result = static_buf;
 114   else
 115     {
 116       /* We don't use the static buffer and so we have a key.  Use it
 117          to get the thread-specific buffer.  */
 118       result = __libc_getspecific (key);
 119       if (result == NULL)
 120         {
 121           /* No buffer allocated so far.  */
 122           result = malloc (BUFFERSIZ);
 123           if (result == NULL)
 124             /* No more memory available.  We use the static buffer.  */
 125             result = local_buf;
 126           else
 127             __libc_setspecific (key, result);
 128         }
 129     }
 130
 131   return result;
 132 }