diff options
Diffstat (limited to 'dlfcn/dlerror.c')
| -rw-r--r-- | dlfcn/dlerror.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c new file mode 100644 index 0000000..c43d511 --- /dev/null +++ b/dlfcn/dlerror.c @@ -0,0 +1,144 @@ +/* Return error detail for failing <dlfcn.h> functions. + Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <dlfcn.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <bits/libc-lock.h> + +/* Type for storing results of dynamic loading actions. */ +struct dl_action_result + { + int errcode; + char *errstring; + }; +static struct dl_action_result last_result; +static struct dl_action_result *static_buf; + + +/* This is the key for the thread specific memory. */ +static __libc_key_t key; + +/* Destructor for the thread-specific data. */ +static void init (void); +static void free_key_mem (void *mem); + + +char * +dlerror (void) +{ + static char *buf; + struct dl_action_result *result; + + if (buf) + { + free (buf); + buf = NULL; + } + + /* Get error string. */ + result = (struct dl_action_result *) __libc_getspecific (key); + if (result == NULL) + result = &last_result; + + if (! result->errstring) + return NULL; + + if (result->errcode == 0) + buf = result->errstring; + else + { + if (__asprintf (&buf, "%s: %s", + result->errstring, strerror (result->errcode)) == -1) + buf = NULL; + + /* We don't need the error string anymore. */ + free (result->errstring); + } + + /* Reset the error indicator. */ + result->errstring = NULL; + + return buf; +} + +int +internal_function +_dlerror_run (void (*operate) (void *), void *args) +{ + __libc_once_define (static, once); + struct dl_action_result *result; + + /* If we have not yet initialized the buffer do it now. */ + __libc_once (once, init); + + /* Get error string and number. */ + if (static_buf != NULL) + result = static_buf; + else + { + /* We don't use the static buffer and so we have a key. Use it + to get the thread-specific buffer. */ + result = __libc_getspecific (key); + if (result == NULL) + { + result = (struct dl_action_result *) calloc (1, sizeof (*result)); + if (result == NULL) + /* We are out of memory. Since this is no really critical + situation we carry on by using the global variable. + This might lead to conflicts between the threads but + they soon all will have memory problems. */ + result = &last_result; + else + /* Set the tsd. */ + __libc_setspecific (key, result); + } + } + + if (result->errstring != NULL) + /* Free the error string from the last failed command. This can + happen if `dlerror' was not run after an error was found. */ + free (result->errstring); + + result->errcode = _dl_catch_error (&result->errstring, operate, args); + + return result->errstring != NULL; +} + + +/* Initialize buffers for results. */ +static void +init (void) +{ + if (__libc_key_create (&key, free_key_mem)) + /* Creating the key failed. This means something really went + wrong. In any case use a static buffer which is better than + nothing. */ + static_buf = &last_result; +} + + +/* Free the thread specific data, this is done if a thread terminates. */ +static void +free_key_mem (void *mem) +{ + free (mem); + __libc_setspecific (key, NULL); +} |