string/strsignal.c

   1 /* Copyright (C) 1991, 94, 95, 96, 97, 98 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 <bits/libc-lock.h>
  24
  25
  26 #ifndef HAVE_GNU_LD
  27 #define _sys_siglist    sys_siglist
  28 #endif
  29
  30 /* Defined in siglist.c.  */
  31 extern const char *const _sys_siglist[];
  32 static __libc_key_t key;
  33
  34 /* If nonzero the key allocation failed and we should better use a
  35    static buffer than fail.  */
  36 #define BUFFERSIZ       100
  37 static char local_buf[BUFFERSIZ];
  38 static char *static_buf;
  39
  40 /* Destructor for the thread-specific data.  */
  41 static void init (void);
  42 static void free_key_mem (void *mem);
  43 static char *getbuffer (void);
  44
  45
  46 /* Return a string describing the meaning of the signal number SIGNUM.  */
  47 char *
  48 strsignal (int signum)
  49 {
  50   __libc_once_define (static, once);
  51   const char *desc;
  52
  53   /* If we have not yet initialized the buffer do it now.  */
  54   __libc_once (once, init);
  55
  56   if (
  57 #ifdef SIGRTMIN
  58       (signum >= SIGRTMIN && signum <= SIGRTMAX) ||
  59 #endif
  60       signum < 0 || signum >= NSIG || (desc = _sys_siglist[signum]) == NULL)
  61     {
  62       char *buffer = getbuffer ();
  63       int len = __snprintf (buffer, BUFFERSIZ - 1,
  64 #ifdef SIGRTMIN
  65                             signum >= SIGRTMIN && signum <= SIGRTMAX
  66                             ? _("Real-time signal %d") :
  67 #endif
  68                             _("Unknown signal %d"), signum);
  69       if (len < 0)
  70         buffer = NULL;
  71       else
  72         buffer[len] = '\0';
  73
  74       return buffer;
  75     }
  76
  77   return (char *) _(desc);
  78 }
  79
  80
  81 /* Initialize buffer.  */
  82 static void
  83 init (void)
  84 {
  85   if (__libc_key_create (&key, free_key_mem))
  86     /* Creating the key failed.  This means something really went
  87        wrong.  In any case use a static buffer which is better than
  88        nothing.  */
  89     static_buf = local_buf;
  90 }
  91
  92
  93 /* Free the thread specific data, this is done if a thread terminates.  */
  94 static void
  95 free_key_mem (void *mem)
  96 {
  97   free (mem);
  98   __libc_setspecific (key, NULL);
  99 }
 100
 101
 102 /* Return the buffer to be used.  */
 103 static char *
 104 getbuffer (void)
 105 {
 106   char *result;
 107
 108   if (static_buf != NULL)
 109     result = static_buf;
 110   else
 111     {
 112       /* We don't use the static buffer and so we have a key.  Use it
 113          to get the thread-specific buffer.  */
 114       result = __libc_getspecific (key);
 115       if (result == NULL)
 116         {
 117           /* No buffer allocated so far.  */
 118           result = malloc (BUFFERSIZ);
 119           if (result == NULL)
 120             /* No more memory available.  We use the static buffer.  */
 121             result = local_buf;
 122           else
 123             __libc_setspecific (key, result);
 124         }
 125     }
 126
 127   return result;
 128 }