string/strsignal.c

   1 /* Copyright (C) 1991, 1994-2002, 2005 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 /* Defined in siglist.c.  */
  28 extern const char *const _sys_siglist[];
  29 extern const char *const _sys_siglist_internal[] attribute_hidden;
  30 static __libc_key_t key;
  31
  32 /* If nonzero the key allocation failed and we should better use a
  33    static buffer than fail.  */
  34 #define BUFFERSIZ       100
  35 static char local_buf[BUFFERSIZ];
  36 static char *static_buf;
  37
  38 /* Destructor for the thread-specific data.  */
  39 static void init (void);
  40 static void free_key_mem (void *mem);
  41 static char *getbuffer (void);
  42
  43
  44 /* Return a string describing the meaning of the signal number SIGNUM.  */
  45 char *
  46 strsignal (int signum)
  47 {
  48   __libc_once_define (static, once);
  49   const char *desc;
  50
  51   /* If we have not yet initialized the buffer do it now.  */
  52   __libc_once (once, init);
  53
  54   if (
  55 #ifdef SIGRTMIN
  56       (signum >= SIGRTMIN && signum <= SIGRTMAX) ||
  57 #endif
  58       signum < 0 || signum >= NSIG
  59       || (desc = INTUSE(_sys_siglist)[signum]) == NULL)
  60     {
  61       char *buffer = getbuffer ();
  62       int len;
  63 #ifdef SIGRTMIN
  64       if (signum >= SIGRTMIN && signum <= SIGRTMAX)
  65         len = __snprintf (buffer, BUFFERSIZ - 1, _("Real-time signal %d"),
  66                           signum - SIGRTMIN);
  67       else
  68 #endif
  69         len = __snprintf (buffer, BUFFERSIZ - 1, _("Unknown signal %d"),
  70                           signum);
  71       if (len >= BUFFERSIZ)
  72         buffer = NULL;
  73       else
  74         buffer[len] = '\0';
  75
  76       return buffer;
  77     }
  78
  79   return (char *) _(desc);
  80 }
  81
  82
  83 /* Initialize buffer.  */
  84 static void
  85 init (void)
  86 {
  87   if (__libc_key_create (&key, free_key_mem))
  88     /* Creating the key failed.  This means something really went
  89        wrong.  In any case use a static buffer which is better than
  90        nothing.  */
  91     static_buf = local_buf;
  92 }
  93
  94
  95 /* Free the thread specific data, this is done if a thread terminates.  */
  96 static void
  97 free_key_mem (void *mem)
  98 {
  99   free (mem);
 100   __libc_setspecific (key, NULL);
 101 }
 102
 103
 104 /* Return the buffer to be used.  */
 105 static char *
 106 getbuffer (void)
 107 {
 108   char *result;
 109
 110   if (static_buf != NULL)
 111     result = static_buf;
 112   else
 113     {
 114       /* We don't use the static buffer and so we have a key.  Use it
 115          to get the thread-specific buffer.  */
 116       result = __libc_getspecific (key);
 117       if (result == NULL)
 118         {
 119           /* No buffer allocated so far.  */
 120           result = malloc (BUFFERSIZ);
 121           if (result == NULL)
 122             /* No more memory available.  We use the static buffer.  */
 123             result = local_buf;
 124           else
 125             __libc_setspecific (key, result);
 126         }
 127     }
 128
 129   return result;
 130 }