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Diffstat (limited to 'REORG.TODO/elf/dl-error-skeleton.c')
| -rw-r--r-- | REORG.TODO/elf/dl-error-skeleton.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/REORG.TODO/elf/dl-error-skeleton.c b/REORG.TODO/elf/dl-error-skeleton.c new file mode 100644 index 0000000000..8e5888d4bd --- /dev/null +++ b/REORG.TODO/elf/dl-error-skeleton.c @@ -0,0 +1,230 @@ +/* Template for error handling for runtime dynamic linker. + Copyright (C) 1995-2017 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 Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +/* The following macro needs to be defined before including this + skeleton file: + + DL_ERROR_BOOTSTRAP + + If 1, do not use TLS and implement _dl_signal_cerror and + _dl_receive_error. If 0, TLS is used, and the variants with + error callbacks are not provided. */ + + +#include <libintl.h> +#include <setjmp.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <ldsodefs.h> +#include <stdio.h> + +/* This structure communicates state between _dl_catch_error and + _dl_signal_error. */ +struct catch + { + const char **objname; /* Object/File name. */ + const char **errstring; /* Error detail filled in here. */ + bool *malloced; /* Nonzero if the string is malloced + by the libc malloc. */ + volatile int *errcode; /* Return value of _dl_signal_error. */ + jmp_buf env; /* longjmp here on error. */ + }; + +/* Multiple threads at once can use the `_dl_catch_error' function. The + calls can come from `_dl_map_object_deps', `_dlerror_run', or from + any of the libc functionality which loads dynamic objects (NSS, iconv). + Therefore we have to be prepared to save the state in thread-local + memory. */ +#if !DL_ERROR_BOOTSTRAP +static __thread struct catch *catch_hook attribute_tls_model_ie; +#else +/* The version of this code in ld.so cannot use thread-local variables + and is used during bootstrap only. */ +static struct catch *catch_hook; +#endif + +/* This message we return as a last resort. We define the string in a + variable since we have to avoid freeing it and so have to enable + a pointer comparison. See below and in dlfcn/dlerror.c. */ +static const char _dl_out_of_memory[] = "out of memory"; + +#if DL_ERROR_BOOTSTRAP +/* This points to a function which is called when an continuable error is + received. Unlike the handling of `catch' this function may return. + The arguments will be the `errstring' and `objname'. + + Since this functionality is not used in normal programs (only in ld.so) + we do not care about multi-threaded programs here. We keep this as a + global variable. */ +static receiver_fct receiver; +#endif /* DL_ERROR_BOOTSTRAP */ + +void +internal_function +_dl_signal_error (int errcode, const char *objname, const char *occation, + const char *errstring) +{ + struct catch *lcatch = catch_hook; + + if (! errstring) + errstring = N_("DYNAMIC LINKER BUG!!!"); + + if (objname == NULL) + objname = ""; + if (lcatch != NULL) + { + /* We are inside _dl_catch_error. Return to it. We have to + duplicate the error string since it might be allocated on the + stack. The object name is always a string constant. */ + size_t len_objname = strlen (objname) + 1; + size_t len_errstring = strlen (errstring) + 1; + + char *errstring_copy = malloc (len_objname + len_errstring); + if (errstring_copy != NULL) + { + /* Make a copy of the object file name and the error string. */ + *lcatch->objname = memcpy (__mempcpy (errstring_copy, + errstring, len_errstring), + objname, len_objname); + *lcatch->errstring = errstring_copy; + + /* If the main executable is relocated it means the libc's malloc + is used. */ + bool malloced = true; +#ifdef SHARED + malloced = (GL(dl_ns)[LM_ID_BASE]._ns_loaded != NULL + && (GL(dl_ns)[LM_ID_BASE]._ns_loaded->l_relocated != 0)); +#endif + *lcatch->malloced = malloced; + } + else + { + /* This is better than nothing. */ + *lcatch->objname = ""; + *lcatch->errstring = _dl_out_of_memory; + *lcatch->malloced = false; + } + + *lcatch->errcode = errcode; + + /* We do not restore the signal mask because none was saved. */ + __longjmp (lcatch->env[0].__jmpbuf, 1); + } + else + { + /* Lossage while resolving the program's own symbols is always fatal. */ + char buffer[1024]; + _dl_fatal_printf ("%s: %s: %s%s%s%s%s\n", + RTLD_PROGNAME, + occation ?: N_("error while loading shared libraries"), + objname, *objname ? ": " : "", + errstring, errcode ? ": " : "", + (errcode + ? __strerror_r (errcode, buffer, sizeof buffer) + : "")); + } +} +libc_hidden_def (_dl_signal_error) + + +#if DL_ERROR_BOOTSTRAP +void +internal_function +_dl_signal_cerror (int errcode, const char *objname, const char *occation, + const char *errstring) +{ + if (__builtin_expect (GLRO(dl_debug_mask) + & ~(DL_DEBUG_STATISTICS|DL_DEBUG_PRELINK), 0)) + _dl_debug_printf ("%s: error: %s: %s (%s)\n", objname, occation, + errstring, receiver ? "continued" : "fatal"); + + if (receiver) + { + /* We are inside _dl_receive_error. Call the user supplied + handler and resume the work. The receiver will still be + installed. */ + (*receiver) (errcode, objname, errstring); + } + else + _dl_signal_error (errcode, objname, occation, errstring); +} +#endif /* DL_ERROR_BOOTSTRAP */ + + +int +internal_function +_dl_catch_error (const char **objname, const char **errstring, + bool *mallocedp, void (*operate) (void *), void *args) +{ + /* We need not handle `receiver' since setting a `catch' is handled + before it. */ + + /* Only this needs to be marked volatile, because it is the only local + variable that gets changed between the setjmp invocation and the + longjmp call. All others are just set here (before setjmp) and read + in _dl_signal_error (before longjmp). */ + volatile int errcode; + + struct catch c; + /* Don't use an initializer since we don't need to clear C.env. */ + c.objname = objname; + c.errstring = errstring; + c.malloced = mallocedp; + c.errcode = &errcode; + + struct catch *const old = catch_hook; + catch_hook = &c; + + /* Do not save the signal mask. */ + if (__builtin_expect (__sigsetjmp (c.env, 0), 0) == 0) + { + (*operate) (args); + catch_hook = old; + *objname = NULL; + *errstring = NULL; + *mallocedp = false; + return 0; + } + + /* We get here only if we longjmp'd out of OPERATE. _dl_signal_error has + already stored values into *OBJNAME, *ERRSTRING, and *MALLOCEDP. */ + catch_hook = old; + return errcode; +} +libc_hidden_def (_dl_catch_error) + +#if DL_ERROR_BOOTSTRAP +void +internal_function +_dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args) +{ + struct catch *old_catch = catch_hook; + receiver_fct old_receiver = receiver; + + /* Set the new values. */ + catch_hook = NULL; + receiver = fct; + + (*operate) (args); + + catch_hook = old_catch; + receiver = old_receiver; +} +#endif /* DL_ERROR_BOOTSTRAP */ |