152 lines
4.1 KiB
C
152 lines
4.1 KiB
C
/* Return error detail for failing <dlfcn.h> functions.
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Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <dlfcn.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <bits/libc-lock.h>
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/* Type for storing results of dynamic loading actions. */
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struct dl_action_result
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{
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int errcode;
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int returned;
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char *errstring;
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};
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static struct dl_action_result last_result;
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static struct dl_action_result *static_buf;
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/* This is the key for the thread specific memory. */
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static __libc_key_t key;
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/* Destructor for the thread-specific data. */
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static void init (void);
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static void free_key_mem (void *mem);
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char *
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dlerror (void)
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{
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char *buf;
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struct dl_action_result *result;
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/* Get error string. */
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result = (struct dl_action_result *) __libc_getspecific (key);
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if (result == NULL)
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result = &last_result;
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/* Test whether we already returned the string. */
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if (result->returned != 0)
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{
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/* We can now free the string. */
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if (result->errstring != NULL)
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{
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free (result->errstring);
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result->errstring = NULL;
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}
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buf = NULL;
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}
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else
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{
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buf = result->errstring;
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if (result->errcode != 0
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&& __asprintf (&buf, "%s: %s",
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result->errstring, strerror (result->errcode)) != -1)
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{
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/* We don't need the error string anymore. */
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free (result->errstring);
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result->errstring = buf;
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}
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/* Mark the error as returned. */
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result->returned = 1;
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}
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return buf;
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}
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int
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internal_function
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_dlerror_run (void (*operate) (void *), void *args)
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{
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__libc_once_define (static, once);
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struct dl_action_result *result;
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/* If we have not yet initialized the buffer do it now. */
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__libc_once (once, init);
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/* Get error string and number. */
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if (static_buf != NULL)
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result = static_buf;
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else
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{
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/* We don't use the static buffer and so we have a key. Use it
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to get the thread-specific buffer. */
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result = __libc_getspecific (key);
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if (result == NULL)
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{
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result = (struct dl_action_result *) calloc (1, sizeof (*result));
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if (result == NULL)
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/* We are out of memory. Since this is no really critical
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situation we carry on by using the global variable.
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This might lead to conflicts between the threads but
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they soon all will have memory problems. */
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result = &last_result;
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else
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/* Set the tsd. */
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__libc_setspecific (key, result);
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}
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}
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if (result->errstring != NULL)
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/* Free the error string from the last failed command. This can
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happen if `dlerror' was not run after an error was found. */
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free (result->errstring);
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result->errcode = _dl_catch_error (&result->errstring, operate, args);
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/* If no error we mark that no error string is available. */
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result->returned = result->errstring == NULL;
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return result->errstring != NULL;
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}
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/* Initialize buffers for results. */
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static void
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init (void)
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{
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if (__libc_key_create (&key, free_key_mem))
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/* Creating the key failed. This means something really went
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wrong. In any case use a static buffer which is better than
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nothing. */
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static_buf = &last_result;
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}
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/* Free the thread specific data, this is done if a thread terminates. */
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static void
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free_key_mem (void *mem)
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{
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free (mem);
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__libc_setspecific (key, NULL);
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}
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