From 4bb377585b95cb67c90ff4ffc21a6870a4e78a37 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Timo=20Ter=C3=A4s?= Date: Fri, 18 Mar 2011 11:40:04 +0200 Subject: [PATCH 3/3] ldso: support RTLD_NOLOAD MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit So application query if specified modile is loaded or not with dlopen. Signed-off-by: Timo Teräs --- ldso/include/dl-elf.h | 6 ++++-- ldso/ldso/dl-elf.c | 30 +++++++++++++++++------------- ldso/ldso/ldso.c | 4 +++- ldso/libdl/libdl.c | 5 +++-- libc/sysdeps/linux/common/bits/dlfcn.h | 4 ++-- 5 files changed, 29 insertions(+), 20 deletions(-) diff --git a/ldso/include/dl-elf.h b/ldso/include/dl-elf.h index 7fbb373..7102351 100644 --- a/ldso/include/dl-elf.h +++ b/ldso/include/dl-elf.h @@ -25,16 +25,18 @@ static __inline__ void _dl_map_cache(void) { } static __inline__ void _dl_unmap_cache(void) { } #endif +#define DL_RESOLVE_SECURE 0x0001 +#define DL_RESOLVE_NOLOAD 0x0002 /* Function prototypes for non-static stuff in readelflib1.c */ extern void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt, unsigned long rel_addr, unsigned long rel_size); extern int _dl_parse_relocation_information(struct dyn_elf *rpnt, unsigned long rel_addr, unsigned long rel_size); -extern struct elf_resolve * _dl_load_shared_library(int secure, +extern struct elf_resolve * _dl_load_shared_library(int resolve_flags, struct dyn_elf **rpnt, struct elf_resolve *tpnt, char *full_libname, int trace_loaded_objects); -extern struct elf_resolve * _dl_load_elf_shared_library(int secure, +extern struct elf_resolve * _dl_load_elf_shared_library(int resolve_flags, struct dyn_elf **rpnt, char *libname); extern struct elf_resolve *_dl_check_if_named_library_is_loaded(const char *full_libname, int trace_loaded_objects); diff --git a/ldso/ldso/dl-elf.c b/ldso/ldso/dl-elf.c index 2b2d429..6d35bf2 100644 --- a/ldso/ldso/dl-elf.c +++ b/ldso/ldso/dl-elf.c @@ -132,7 +132,7 @@ _dl_protect_relro (struct elf_resolve *l) /* This function's behavior must exactly match that * in uClibc/ldso/util/ldd.c */ static struct elf_resolve * -search_for_named_library(const char *name, int secure, const char *path_list, +search_for_named_library(const char *name, int resolve_flags, const char *path_list, struct dyn_elf **rpnt, const char *origin) { char *mylibname; @@ -162,7 +162,7 @@ search_for_named_library(const char *name, int secure, const char *path_list, if (plen >= 7 && _dl_memcmp(p, "$ORIGIN", 7) == 0) { int olen; - if (secure && plen != 7) + if ((resolve_flags & DL_RESOLVE_SECURE) && plen != 7) continue; if (origin == NULL) continue; @@ -182,7 +182,7 @@ search_for_named_library(const char *name, int secure, const char *path_list, _dl_strcat(mylibname, "/"); _dl_strcat(mylibname, name); - tpnt = _dl_load_elf_shared_library(secure, rpnt, mylibname); + tpnt = _dl_load_elf_shared_library(resolve_flags, rpnt, mylibname); if (tpnt != NULL) return tpnt; } @@ -194,7 +194,7 @@ search_for_named_library(const char *name, int secure, const char *path_list, unsigned long _dl_error_number; unsigned long _dl_internal_error_number; -struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt, +struct elf_resolve *_dl_load_shared_library(int resolve_flags, struct dyn_elf **rpnt, struct elf_resolve *tpnt, char *full_libname, int attribute_unused trace_loaded_objects) { char *pnt; @@ -223,7 +223,7 @@ struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt, if (libname != full_libname) { _dl_if_debug_dprint("\ttrying file='%s'\n", full_libname); - tpnt1 = _dl_load_elf_shared_library(secure, rpnt, full_libname); + tpnt1 = _dl_load_elf_shared_library(resolve_flags, rpnt, full_libname); if (tpnt1) { return tpnt1; } @@ -238,7 +238,7 @@ struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt, if (pnt) { pnt += (unsigned long) tpnt->dynamic_info[DT_STRTAB]; _dl_if_debug_dprint("\tsearching RPATH='%s'\n", pnt); - if ((tpnt1 = search_for_named_library(libname, secure, pnt, rpnt, + if ((tpnt1 = search_for_named_library(libname, resolve_flags, pnt, rpnt, tpnt->libname)) != NULL) return tpnt1; } @@ -247,7 +247,7 @@ struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt, /* Check in LD_{ELF_}LIBRARY_PATH, if specified and allowed */ if (_dl_library_path) { _dl_if_debug_dprint("\tsearching LD_LIBRARY_PATH='%s'\n", _dl_library_path); - if ((tpnt1 = search_for_named_library(libname, secure, _dl_library_path, rpnt, NULL)) != NULL) + if ((tpnt1 = search_for_named_library(libname, resolve_flags, _dl_library_path, rpnt, NULL)) != NULL) { return tpnt1; } @@ -261,7 +261,7 @@ struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt, if (pnt) { pnt += (unsigned long) tpnt->dynamic_info[DT_STRTAB]; _dl_if_debug_dprint("\tsearching RUNPATH='%s'\n", pnt); - if ((tpnt1 = search_for_named_library(libname, secure, pnt, rpnt, NULL)) != NULL) + if ((tpnt1 = search_for_named_library(libname, resolve_flags, pnt, rpnt, NULL)) != NULL) return tpnt1; } #endif @@ -284,7 +284,7 @@ struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt, || libent[i].flags == LIB_ELF_LIBC0 || libent[i].flags == LIB_ELF_LIBC5) && _dl_strcmp(libname, strs + libent[i].sooffset) == 0 - && (tpnt1 = _dl_load_elf_shared_library(secure, rpnt, strs + libent[i].liboffset)) + && (tpnt1 = _dl_load_elf_shared_library(resolve_flags, rpnt, strs + libent[i].liboffset)) ) { return tpnt1; } @@ -295,14 +295,14 @@ struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt, /* Look for libraries wherever the shared library loader * was installed */ _dl_if_debug_dprint("\tsearching ldso dir='%s'\n", _dl_ldsopath); - tpnt1 = search_for_named_library(libname, secure, _dl_ldsopath, rpnt, NULL); + tpnt1 = search_for_named_library(libname, resolve_flags, _dl_ldsopath, rpnt, NULL); if (tpnt1 != NULL) return tpnt1; /* Lastly, search the standard list of paths for the library. This list must exactly match the list in uClibc/ldso/util/ldd.c */ _dl_if_debug_dprint("\tsearching full lib path list\n"); - tpnt1 = search_for_named_library(libname, secure, + tpnt1 = search_for_named_library(libname, resolve_flags, UCLIBC_RUNTIME_PREFIX "lib:" UCLIBC_RUNTIME_PREFIX "usr/lib" #ifndef __LDSO_CACHE_SUPPORT__ @@ -329,7 +329,7 @@ goof: * are required. */ -struct elf_resolve *_dl_load_elf_shared_library(int secure, +struct elf_resolve *_dl_load_elf_shared_library(int resolve_flags, struct dyn_elf **rpnt, char *libname) { ElfW(Ehdr) *epnt; @@ -368,7 +368,7 @@ struct elf_resolve *_dl_load_elf_shared_library(int secure, } /* If we are in secure mode (i.e. a setu/gid binary using LD_PRELOAD), we don't load the library if it isn't setuid. */ - if (secure) { + if (resolve_flags & DL_RESOLVE_SECURE) { if (!(st.st_mode & S_ISUID)) { _dl_close(infile); return NULL; @@ -384,6 +384,10 @@ struct elf_resolve *_dl_load_elf_shared_library(int secure, return tpnt; } } + if (resolve_flags & DL_RESOLVE_NOLOAD) { + _dl_close(infile); + return NULL; + } header = _dl_mmap((void *) 0, _dl_pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_UNINITIALIZE, -1, 0); if (_dl_mmap_check_error(header)) { diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c index 9423670..b71af34 100644 --- a/ldso/ldso/ldso.c +++ b/ldso/ldso/ldso.c @@ -646,7 +646,9 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr, if (!_dl_secure || _dl_strchr(str, '/') == NULL) { _dl_if_debug_dprint("\tfile='%s'; needed by '%s'\n", str, _dl_progname); - tpnt1 = _dl_load_shared_library(_dl_secure, &rpnt, NULL, str, trace_loaded_objects); + tpnt1 = _dl_load_shared_library( + _dl_secure ? DL_RESOLVE_SECURE : 0, + &rpnt, NULL, str, trace_loaded_objects); if (!tpnt1) { #ifdef __LDSO_LDD_SUPPORT__ if (trace_loaded_objects) diff --git a/ldso/libdl/libdl.c b/ldso/libdl/libdl.c index 68cd579..edf38d2 100644 --- a/ldso/libdl/libdl.c +++ b/ldso/libdl/libdl.c @@ -288,7 +288,7 @@ void *dlopen(const char *libname, int flag) #endif /* A bit of sanity checking... */ - if (!(flag & (RTLD_LAZY|RTLD_NOW))) { + if (!(flag & (RTLD_LAZY|RTLD_NOW|RTLD_NOLOAD))) { _dl_error_number = LD_BAD_HANDLE; return NULL; } @@ -358,8 +358,9 @@ void *dlopen(const char *libname, int flag) /* Try to load the specified library */ _dl_if_debug_print("Trying to dlopen '%s', RTLD_GLOBAL:%d RTLD_NOW:%d\n", (char*)libname, (flag & RTLD_GLOBAL ? 1:0), (now_flag & RTLD_NOW ? 1:0)); - tpnt = _dl_load_shared_library(0, &rpnt, tfrom, (char*)libname, 0); + tpnt = _dl_load_shared_library((flag & RTLD_NOLOAD) ? DL_RESOLVE_NOLOAD : 0, + &rpnt, tfrom, (char*)libname, 0); if (tpnt == NULL) { _dl_unmap_cache(); return NULL; diff --git a/libc/sysdeps/linux/common/bits/dlfcn.h b/libc/sysdeps/linux/common/bits/dlfcn.h index 4bfbbff..47b42ad 100644 --- a/libc/sysdeps/linux/common/bits/dlfcn.h +++ b/libc/sysdeps/linux/common/bits/dlfcn.h @@ -24,9 +24,9 @@ /* The MODE argument to `dlopen' contains one of the following: */ #define RTLD_LAZY 0x00001 /* Lazy function call binding. */ #define RTLD_NOW 0x00002 /* Immediate function call binding. */ -#if 0 /* uClibc doesnt support these */ -#define RTLD_BINDING_MASK 0x3 /* Mask of binding time value. */ +#define RTLD_BINDING_MASK 0x3 /* Mask of binding time value. */ #define RTLD_NOLOAD 0x00004 /* Do not load the object. */ +#if 0 /* uClibc doesnt support these */ #define RTLD_DEEPBIND 0x00008 /* Use deep binding. */ #endif -- 1.7.1