string/strsignal.c

   1 /* Copyright (C) 1991, 1994-2000, 2001, 2002 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    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 extern const char *const _sys_siglist_internal[] attribute_hidden;
  34 static __libc_key_t key;
  35
  36 /* If nonzero the key allocation failed and we should better use a
  37    static buffer than fail.  */
  38 #define BUFFERSIZ       100
  39 static char local_buf[BUFFERSIZ];
  40 static char *static_buf;
  41
  42 /* Destructor for the thread-specific data.  */
  43 static void init (void);
  44 static void free_key_mem (void *mem);
  45 static char *getbuffer (void);
  46
  47
  48 /* Return a string describing the meaning of the signal number SIGNUM.  */
  49 char *
  50 strsignal (int signum)
  51 {
  52   __libc_once_define (static, once);
  53   const char *desc;
  54
  55   /* If we have not yet initialized the buffer do it now.  */
  56   __libc_once (once, init);
  57
  58   if (
  59 #ifdef SIGRTMIN
  60       (signum >= SIGRTMIN && signum <= SIGRTMAX) ||
  61 #endif
  62       signum < 0 || signum >= NSIG
  63       || (desc = INTUSE(_sys_siglist)[signum]) == NULL)
  64     {
  65       char *buffer = getbuffer ();
  66       int len;
  67 #ifdef SIGRTMIN
  68       if (signum >= SIGRTMIN && signum <= SIGRTMAX)
  69         len = __snprintf (buffer, BUFFERSIZ - 1, _("Real-time signal %d"),
  70                           signum - SIGRTMIN);
  71       else
  72 #endif
  73         len = __snprintf (buffer, BUFFERSIZ - 1, _("Unknown signal %d"),
  74                           signum);
  75       if (len >= BUFFERSIZ)
  76         buffer = NULL;
  77       else
  78         buffer[len] = '\0';
  79
  80       return buffer;
  81     }
  82
  83   return (char *) _(desc);
  84 }
  85
  86
  87 /* Initialize buffer.  */
  88 static void
  89 init (void)
  90 {
  91   if (__libc_key_create (&key, free_key_mem))
  92     /* Creating the key failed.  This means something really went
  93        wrong.  In any case use a static buffer which is better than
  94        nothing.  */
  95     static_buf = local_buf;
  96 }
  97
  98
  99 /* Free the thread specific data, this is done if a thread terminates.  */
 100 static void
 101 free_key_mem (void *mem)
 102 {
 103   free (mem);
 104   __libc_setspecific (key, NULL);
 105 }
 106
 107
 108 /* Return the buffer to be used.  */
 109 static char *
 110 getbuffer (void)
 111 {
 112   char *result;
 113
 114   if (static_buf != NULL)
 115     result = static_buf;
 116   else
 117     {
 118       /* We don't use the static buffer and so we have a key.  Use it
 119          to get the thread-specific buffer.  */
 120       result = __libc_getspecific (key);
 121       if (result == NULL)
 122         {
 123           /* No buffer allocated so far.  */
 124           result = malloc (BUFFERSIZ);
 125           if (result == NULL)
 126             /* No more memory available.  We use the static buffer.  */
 127             result = local_buf;
 128           else
 129             __libc_setspecific (key, result);
 130         }
 131     }
 132
 133   return result;
 134 }