diff options
Diffstat (limited to 'lib/libc/gen/dlfcn.c')
| -rw-r--r-- | lib/libc/gen/dlfcn.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/lib/libc/gen/dlfcn.c b/lib/libc/gen/dlfcn.c new file mode 100644 index 0000000..74cdc8b --- /dev/null +++ b/lib/libc/gen/dlfcn.c @@ -0,0 +1,182 @@ +/*- + * Copyright (c) 1998 John D. Polstra + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * Linkage to services provided by the dynamic linker. These are + * implemented differently in ELF and a.out, because the dynamic + * linkers have different interfaces. + */ +#ifdef __ELF__ + +#include <dlfcn.h> +#include <stddef.h> + +static const char sorry[] = "Service unavailable"; + +/* + * For ELF, the dynamic linker directly resolves references to its + * services to functions inside the dynamic linker itself. These + * weak-symbol stubs are necessary so that "ld" won't complain about + * undefined symbols. The stubs are executed only when the program is + * linked statically, or when a given service isn't implemented in the + * dynamic linker. They must return an error if called, and they must + * be weak symbols so that the dynamic linker can override them. + */ + +#pragma weak _rtld_error +void +_rtld_error(const char *fmt, ...) +{ +} + +#pragma weak dladdr +int +dladdr(const void *addr, Dl_info *dlip) +{ + _rtld_error(sorry); + return 0; +} + +#pragma weak dlclose +int +dlclose(void *handle) +{ + _rtld_error(sorry); + return -1; +} + +#pragma weak dlerror +const char * +dlerror(void) +{ + return sorry; +} + +#pragma weak dllockinit +void +dllockinit(void *context, + void *(*lock_create)(void *context), + void (*rlock_acquire)(void *lock), + void (*wlock_acquire)(void *lock), + void (*lock_release)(void *lock), + void (*lock_destroy)(void *lock), + void (*context_destroy)(void *context)) +{ + if (context_destroy != NULL) + context_destroy(context); +} + +#pragma weak dlopen +void * +dlopen(const char *name, int mode) +{ + _rtld_error(sorry); + return NULL; +} + +#pragma weak dlsym +void * +dlsym(void *handle, const char *name) +{ + _rtld_error(sorry); + return NULL; +} + +#else /* a.out format */ + +#include <sys/types.h> +#include <nlist.h> /* XXX - Required by link.h */ +#include <dlfcn.h> +#include <link.h> +#include <stddef.h> + +/* + * For a.out, entry to the dynamic linker is via these trampolines. + * They enter the dynamic linker through the ld_entry struct that was + * passed back from the dynamic linker at startup time. + */ + +/* GCC is needed because we use its __builtin_return_address construct. */ + +#ifndef __GNUC__ +#error "GCC is needed to compile this file" +#endif + +/* + * These variables are set by code in crt0.o. For compatibility with + * old executables, they must be common, not extern. + */ +struct ld_entry *__ldso_entry; /* Entry points to dynamic linker */ +int __ldso_version; /* Dynamic linker version number */ + +int +dladdr(const void *addr, Dl_info *dlip) +{ + if (__ldso_entry == NULL || __ldso_version < LDSO_VERSION_HAS_DLADDR) + return 0; + return (__ldso_entry->dladdr)(addr, dlip); +} + +int +dlclose(void *handle) +{ + if (__ldso_entry == NULL) + return -1; + return (__ldso_entry->dlclose)(handle); +} + +const char * +dlerror(void) +{ + if (__ldso_entry == NULL) + return "Service unavailable"; + return (__ldso_entry->dlerror)(); +} + +void * +dlopen(const char *name, int mode) +{ + if (__ldso_entry == NULL) + return NULL; + return (__ldso_entry->dlopen)(name, mode); +} + +void * +dlsym(void *handle, const char *name) +{ + if (__ldso_entry == NULL) + return NULL; + if (__ldso_version >= LDSO_VERSION_HAS_DLSYM3) { + void *retaddr = __builtin_return_address(0); /* __GNUC__ only */ + return (__ldso_entry->dlsym3)(handle, name, retaddr); + } else + return (__ldso_entry->dlsym)(handle, name); +} + +#endif /* __ELF__ */ |
