diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/Makefile | 7 | ||||
| -rw-r--r-- | elf/dl-close.c | 107 | ||||
| -rw-r--r-- | elf/dl-deps.c | 4 | ||||
| -rw-r--r-- | elf/dl-load.c | 314 | ||||
| -rw-r--r-- | elf/dl-lookup.c | 125 | ||||
| -rw-r--r-- | elf/dl-object.c | 12 | ||||
| -rw-r--r-- | elf/dl-open.c | 81 | ||||
| -rw-r--r-- | elf/dl-reloc.c | 33 | ||||
| -rw-r--r-- | elf/dl-runtime.c | 58 | ||||
| -rw-r--r-- | elf/dlclose.c | 70 | ||||
| -rw-r--r-- | elf/dlopen.c | 2 | ||||
| -rw-r--r-- | elf/link.h | 68 | ||||
| -rw-r--r-- | elf/rtld.c | 83 |
13 files changed, 574 insertions, 390 deletions
diff --git a/elf/Makefile b/elf/Makefile index 06aeb7590a..c2c8f7c5b2 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -21,7 +21,8 @@ subdir := elf headers = elf.h elfclass.h link.h dlfcn.h -routines = init-first $(dl-routines) dl-open dl-symbol dl-support +routines = init-first $(dl-routines) \ + dl-open dl-close dl-symbol dl-support # The core dynamic linking functions are in libc for the static and # profiled libraries. @@ -54,7 +55,7 @@ install-bin = ldd # to run programs during the `make others' pass. lib-noranlib: $(objpfx)ld.so $(addprefix $(objpfx),$(extra-objs)) -ifneq (,$(filter linux%,$(config-os))) +ifneq (,$(filter linux% linux,$(config-os))) extra-objs += linux-compat.so install-others += $(slibdir)/ld-linux.so.1 lib-noranlib: $(objpfx)ld-linux.so.1 @@ -75,7 +76,7 @@ $(objpfx)dl-allobjs.so: $(rtld-routines:%=$(objpfx)%.so) # dynamic linker shared objects below. $(objpfx)librtld.so: $(objpfx)dl-allobjs.so \ $(patsubst %,$(common-objpfx)lib%_pic.a,\ - elf c $(LDLIBS-c.so:-l%=%)) + c $(LDLIBS-c.so:-l%=%)) $(reloc-link) '-Wl,-(' $^ -lgcc '-Wl,-)' $(objpfx)ld.so: $(objpfx)librtld.so diff --git a/elf/dl-close.c b/elf/dl-close.c new file mode 100644 index 0000000000..69fdefac95 --- /dev/null +++ b/elf/dl-close.c @@ -0,0 +1,107 @@ +/* _dl_close -- Close a shared object opened by `_dl_open'. +Copyright (C) 1996 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., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <link.h> +#include <dlfcn.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/mman.h> + + +#define LOSE(s) _dl_signal_error (0, map->l_name, s) + +void +_dl_close (struct link_map *map) +{ + struct link_map **list; + unsigned int i; + + if (map->l_opencount == 0) + LOSE ("shared object not open"); + + /* Decrement the reference count. */ + if (--map->l_opencount > 0 || map->l_type != lt_loaded) + /* There are still references to this object. Do nothing more. */ + return; + + list = map->l_searchlist; + + /* The search list contains a counted reference to each object it + points to, the 0th elt being MAP itself. Decrement the reference + counts on all the objects MAP depends on. */ + for (i = 1; i < map->l_nsearchlist; ++i) + --list[i]->l_opencount; + + /* Clear the search list so it doesn't get freed while we are still + using it. We have cached it in LIST and will free it when + finished. */ + map->l_searchlist = NULL; + + /* Check each element of the search list to see if all references to + it are gone. */ + for (i = 0; i < map->l_nsearchlist; ++i) + { + struct link_map *map = list[i]; + if (map->l_opencount == 0 && map->l_type == lt_loaded) + { + /* That was the last reference, and this was a dlopen-loaded + object. We can unmap it. */ + const ElfW(Phdr) *ph; + + if (map->l_info[DT_FINI]) + /* Call its termination function. */ + (*(void (*) (void)) ((void *) map->l_addr + + map->l_info[DT_FINI]->d_un.d_ptr)) (); + + if (map->l_global) + { + /* This object is in the global scope list. Remove it. */ + struct link_map **tail = _dl_global_scope_end; + do + --tail; + while (*tail != map); + --_dl_global_scope_end; + memcpy (tail, tail + 1, _dl_global_scope_end - tail); + _dl_global_scope_end[0] = NULL; + _dl_global_scope_end[1] = NULL; + } + + /* Unmap the segments. */ + for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph) + if (ph->p_type == PT_LOAD) + { + ElfW(Addr) mapstart = ph->p_vaddr & ~(ph->p_align - 1); + ElfW(Addr) mapend = ((ph->p_vaddr + ph->p_memsz + + ph->p_align - 1) + & ~(ph->p_align - 1)); + __munmap ((caddr_t) mapstart, mapend - mapstart); + } + + /* Finally, unlink the data structure and free it. */ + map->l_prev->l_next = map->l_next; + if (map->l_next) + map->l_next->l_prev = map->l_prev; + if (map->l_searchlist) + free (map->l_searchlist); + free (map); + } + } + + free (list); +} diff --git a/elf/dl-deps.c b/elf/dl-deps.c index 7e3b259362..3e49fcfe01 100644 --- a/elf/dl-deps.c +++ b/elf/dl-deps.c @@ -62,7 +62,9 @@ _dl_map_object_deps (struct link_map *map) { /* Map in the needed object. */ struct link_map *dep - = _dl_map_object (l, strtab + d->d_un.d_val); + = _dl_map_object (l, strtab + d->d_un.d_val, + l->l_type == lt_executable ? lt_library : + l->l_type); if (dep->l_reserved) /* This object is already in the search list we are diff --git a/elf/dl-load.c b/elf/dl-load.c index c6acc8c222..b9f4aa184b 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -63,152 +63,14 @@ int _dl_zerofd = -1; size_t _dl_pagesize; -/* Try to open NAME in one of the directories in DIRPATH. - Return the fd, or -1. If successful, fill in *REALNAME - with the malloc'd full directory name. */ - -static int -open_path (const char *name, size_t namelen, - const char *dirpath, - char **realname) -{ - char *buf; - const char *p; - int fd; - - p = dirpath; - if (p == NULL || *p == '\0') - { - errno = ENOENT; - return -1; - } - - buf = __alloca (strlen (dirpath) + 1 + namelen); - do - { - size_t buflen; - - dirpath = p; - p = strpbrk (dirpath, ":;"); - if (p == NULL) - p = strchr (dirpath, '\0'); - - if (p == dirpath) - { - /* Two adjacent colons, or a colon at the beginning or the end of - the path means to search the current directory. */ - (void) memcpy (buf, name, namelen); - buflen = namelen; - } - else - { - /* Construct the pathname to try. */ - (void) memcpy (buf, dirpath, p - dirpath); - buf[p - dirpath] = '/'; - (void) memcpy (&buf[(p - dirpath) + 1], name, namelen); - buflen = p - dirpath + 1 + namelen; - } - - fd = __open (buf, O_RDONLY); - if (fd != -1) - { - *realname = malloc (buflen); - if (*realname) - { - memcpy (*realname, buf, buflen); - return fd; - } - else - { - /* No memory for the name, we certainly won't be able - to load and link it. */ - __close (fd); - return -1; - } - } - if (errno != ENOENT && errno != EACCES) - /* The file exists and is readable, but something went wrong. */ - return -1; - } - while (*p++ != '\0'); - - return -1; -} - -/* Map in the shared object file NAME. */ - -struct link_map * -_dl_map_object (struct link_map *loader, const char *name) -{ - int fd; - char *realname; - struct link_map *l; - - /* Look for this name among those already loaded. */ - for (l = _dl_loaded; l; l = l->l_next) - if (! strcmp (name, l->l_libname)) - { - /* The object is already loaded. - Just bump its reference count and return it. */ - ++l->l_opencount; - return l; - } - - if (strchr (name, '/') == NULL) - { - /* Search for NAME in several places. */ - - size_t namelen = strlen (name) + 1; - - inline void trypath (const char *dirpath) - { - fd = open_path (name, namelen, dirpath, &realname); - } - - fd = -1; - if (loader && loader->l_info[DT_RPATH]) - trypath ((const char *) (loader->l_addr + - loader->l_info[DT_STRTAB]->d_un.d_ptr + - loader->l_info[DT_RPATH]->d_un.d_val)); - if (fd == -1 && ! _dl_secure) - trypath (getenv ("LD_LIBRARY_PATH")); - if (fd == -1) - { - extern const char *_dl_rpath; /* Set in rtld.c. */ - trypath (_dl_rpath); - } - } - else - { - fd = __open (name, O_RDONLY); - if (fd != -1) - { - size_t len = strlen (name) + 1; - realname = malloc (len); - if (realname) - memcpy (realname, name, len); - else - { - __close (fd); - fd = -1; - } - } - } - - if (fd == -1) - _dl_signal_error (errno, name, "cannot open shared object file"); - - return _dl_map_object_from_fd (name, fd, realname); -} - - /* Map in the shared object NAME, actually located in REALNAME, and already opened on FD. */ struct link_map * -_dl_map_object_from_fd (const char *name, int fd, char *realname) +_dl_map_object_from_fd (const char *name, int fd, char *realname, + struct link_map *loader, int l_type) { - struct link_map *l = NULL; + struct link_map *l; void *file_mapping = NULL; size_t mapping_size = 0; @@ -218,7 +80,17 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname) (void) __close (fd); if (file_mapping) __munmap (file_mapping, mapping_size); - _dl_signal_error (code, l ? l->l_name : name, msg); + if (l) + { + /* Remove the stillborn object from the list and free it. */ + if (l->l_prev) + l->l_prev->l_next = l->l_next; + if (l->l_next) + l->l_next->l_prev = l->l_prev; + free (l); + } + free (realname); + _dl_signal_error (code, name, msg); } inline caddr_t map_segment (ElfW(Addr) mapstart, size_t len, @@ -304,17 +176,23 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname) if (header->e_phentsize != sizeof (ElfW(Phdr))) LOSE ("ELF file's phentsize not the expected size"); - /* Enter the new object in the list of loaded objects. */ - l = _dl_new_object (realname, name, lt_loaded); - l->l_opencount = 1; - if (_dl_zerofd == -1) { _dl_zerofd = _dl_sysdep_open_zero_fill (); if (_dl_zerofd == -1) - _dl_signal_error (errno, NULL, "cannot open zero fill device"); + { + __close (fd); + _dl_signal_error (errno, NULL, "cannot open zero fill device"); + } } + /* Enter the new object in the list of loaded objects. */ + l = _dl_new_object (realname, name, l_type); + if (! l) + lose (ENOMEM, "cannot create shared object descriptor"); + l->l_opencount = 1; + l->l_loader = loader; + /* Extract the remaining details we need from the ELF header and then map in the program header table. */ l->l_entry = header->e_entry; @@ -464,7 +342,8 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname) /* We are done mapping in the file. We no longer need the descriptor. */ __close (fd); - l->l_type = type == ET_EXEC ? lt_executable : lt_library; + if (l->l_type == lt_library && type == ET_EXEC) + l->l_type = lt_executable; if (l->l_ld == 0) { @@ -484,3 +363,142 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname) return l; } + +/* Try to open NAME in one of the directories in DIRPATH. + Return the fd, or -1. If successful, fill in *REALNAME + with the malloc'd full directory name. */ + +static int +open_path (const char *name, size_t namelen, + const char *dirpath, + char **realname) +{ + char *buf; + const char *p; + int fd; + + p = dirpath; + if (p == NULL || *p == '\0') + { + errno = ENOENT; + return -1; + } + + buf = __alloca (strlen (dirpath) + 1 + namelen); + do + { + size_t buflen; + + dirpath = p; + p = strpbrk (dirpath, ":;"); + if (p == NULL) + p = strchr (dirpath, '\0'); + + if (p == dirpath) + { + /* Two adjacent colons, or a colon at the beginning or the end of + the path means to search the current directory. */ + (void) memcpy (buf, name, namelen); + buflen = namelen; + } + else + { + /* Construct the pathname to try. */ + (void) memcpy (buf, dirpath, p - dirpath); + buf[p - dirpath] = '/'; + (void) memcpy (&buf[(p - dirpath) + 1], name, namelen); + buflen = p - dirpath + 1 + namelen; + } + + fd = __open (buf, O_RDONLY); + if (fd != -1) + { + *realname = malloc (buflen); + if (*realname) + { + memcpy (*realname, buf, buflen); + return fd; + } + else + { + /* No memory for the name, we certainly won't be able + to load and link it. */ + __close (fd); + return -1; + } + } + if (errno != ENOENT && errno != EACCES) + /* The file exists and is readable, but something went wrong. */ + return -1; + } + while (*p++ != '\0'); + + return -1; +} + +/* Map in the shared object file NAME. */ + +struct link_map * +_dl_map_object (struct link_map *loader, const char *name, int type) +{ + int fd; + char *realname; + struct link_map *l; + + /* Look for this name among those already loaded. */ + for (l = _dl_loaded; l; l = l->l_next) + if (! strcmp (name, l->l_libname)) + { + /* The object is already loaded. + Just bump its reference count and return it. */ + ++l->l_opencount; + return l; + } + + if (strchr (name, '/') == NULL) + { + /* Search for NAME in several places. */ + + size_t namelen = strlen (name) + 1; + + inline void trypath (const char *dirpath) + { + fd = open_path (name, namelen, dirpath, &realname); + } + + fd = -1; + for (l = loader; l; l = l->l_loader) + if (l && l->l_info[DT_RPATH]) + trypath ((const char *) (l->l_addr + + l->l_info[DT_STRTAB]->d_un.d_ptr + + l->l_info[DT_RPATH]->d_un.d_val)); + if (fd == -1 && ! _dl_secure) + trypath (getenv ("LD_LIBRARY_PATH")); + if (fd == -1) + { + extern const char *_dl_rpath; /* Set in rtld.c. */ + trypath (_dl_rpath); + } + } + else + { + fd = __open (name, O_RDONLY); + if (fd != -1) + { + size_t len = strlen (name) + 1; + realname = malloc (len); + if (realname) + memcpy (realname, name, len); + else + { + __close (fd); + fd = -1; + } + } + } + + if (fd == -1) + _dl_signal_error (errno, name, "cannot open shared object file"); + + return _dl_map_object_from_fd (name, fd, realname, loader, type); +} diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 0674253041..5f1e6d03d9 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -50,7 +50,7 @@ _dl_elf_hash (const char *name) ElfW(Addr) _dl_lookup_symbol (const char *undef_name, const ElfW(Sym) **ref, - struct link_map *symbol_scope[2], + struct link_map *symbol_scope[], const char *reference_name, ElfW(Addr) reloc_addr, int noplt) @@ -65,69 +65,68 @@ _dl_lookup_symbol (const char *undef_name, const ElfW(Sym) **ref, struct link_map **scope, *map; /* Search the relevant loaded objects for a definition. */ - for (scope = symbol_scope; scope < &symbol_scope[2]; ++scope) - if (*scope) - for (i = 0; i < (*scope)->l_nsearchlist; ++i) - { - const ElfW(Sym) *symtab; - const char *strtab; - ElfW(Word) symidx; - - map = (*scope)->l_searchlist[i]; - - symtab = ((void *) map->l_addr + map->l_info[DT_SYMTAB]->d_un.d_ptr); - strtab = ((void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr); - - /* Search the appropriate hash bucket in this object's symbol table - for a definition for the same symbol name. */ - for (symidx = map->l_buckets[hash % map->l_nbuckets]; - symidx != STN_UNDEF; - symidx = map->l_chain[symidx]) - { - const ElfW(Sym) *sym = &symtab[symidx]; - - if (sym->st_value == 0 || /* No value. */ - /* Cannot resolve to the location being filled in. */ - reloc_addr == map->l_addr + sym->st_value || - (noplt && sym->st_shndx == SHN_UNDEF)) /* Reject PLT. */ - continue; - - switch (ELFW(ST_TYPE) (sym->st_info)) - { - case STT_NOTYPE: - case STT_FUNC: - case STT_OBJECT: - break; - default: - /* Not a code/data definition. */ - continue; - } - - if (sym != *ref && strcmp (strtab + sym->st_name, undef_name)) - /* Not the symbol we are looking for. */ + for (scope = symbol_scope; *scope; ++scope) + for (i = 0; i < (*scope)->l_nsearchlist; ++i) + { + const ElfW(Sym) *symtab; + const char *strtab; + ElfW(Word) symidx; + + map = (*scope)->l_searchlist[i]; + + symtab = ((void *) map->l_addr + map->l_info[DT_SYMTAB]->d_un.d_ptr); + strtab = ((void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr); + + /* Search the appropriate hash bucket in this object's symbol table + for a definition for the same symbol name. */ + for (symidx = map->l_buckets[hash % map->l_nbuckets]; + symidx != STN_UNDEF; + symidx = map->l_chain[symidx]) + { + const ElfW(Sym) *sym = &symtab[symidx]; + + if (sym->st_value == 0 || /* No value. */ + /* Cannot resolve to the location being filled in. */ + reloc_addr == map->l_addr + sym->st_value || + (noplt && sym->st_shndx == SHN_UNDEF)) /* Reject PLT. */ + continue; + + switch (ELFW(ST_TYPE) (sym->st_info)) + { + case STT_NOTYPE: + case STT_FUNC: + case STT_OBJECT: + break; + default: + /* Not a code/data definition. */ continue; - - switch (ELFW(ST_BIND) (sym->st_info)) - { - case STB_GLOBAL: - /* Global definition. Just what we need. */ - *ref = sym; - return map->l_addr; - case STB_WEAK: - /* Weak definition. Use this value if we don't find - another. */ - if (! weak_value.s) - { - weak_value.s = sym; - weak_value.a = map->l_addr; - } - break; - default: - /* Local symbols are ignored. */ - break; - } - } - } + } + + if (sym != *ref && strcmp (strtab + sym->st_name, undef_name)) + /* Not the symbol we are looking for. */ + continue; + + switch (ELFW(ST_BIND) (sym->st_info)) + { + case STB_GLOBAL: + /* Global definition. Just what we need. */ + *ref = sym; + return map->l_addr; + case STB_WEAK: + /* Weak definition. Use this value if we don't find + another. */ + if (! weak_value.s) + { + weak_value.s = sym; + weak_value.a = map->l_addr; + } + break; + default: + /* Local symbols are ignored. */ + break; + } + } + } if (weak_value.s == NULL && ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK) { diff --git a/elf/dl-object.c b/elf/dl-object.c index 11e9e082d2..851d133df3 100644 --- a/elf/dl-object.c +++ b/elf/dl-object.c @@ -1,5 +1,5 @@ /* Storage management for the chain of loaded shared objects. -Copyright (C) 1995 Free Software Foundation, Inc. +Copyright (C) 1995, 1996 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 @@ -24,11 +24,8 @@ Cambridge, MA 02139, USA. */ #include <errno.h> -/* List of objects currently loaded. */ -struct link_map *_dl_loaded; - -/* Tail of that list which were loaded at startup. */ -struct link_map *_dl_startup_loaded; +/* List of objects currently loaded is [2] of this, aka _dl_loaded. */ +struct link_map *_dl_default_scope[5]; /* Allocate a `struct link_map' for a new object being loaded, and enter it into the _dl_loaded list. */ @@ -38,8 +35,7 @@ _dl_new_object (char *realname, const char *libname, int type) { struct link_map *new = malloc (sizeof *new); if (! new) - _dl_signal_error (ENOMEM, libname, - "cannot allocate shared object descriptor"); + return NULL; memset (new, 0, sizeof *new); new->l_name = realname; diff --git a/elf/dl-open.c b/elf/dl-open.c index 221abbd35e..9389303b90 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -19,6 +19,10 @@ Cambridge, MA 02139, USA. */ #include <link.h> #include <dlfcn.h> +#include <stdlib.h> +#include <errno.h> + +size_t _dl_global_scope_alloc; struct link_map * _dl_open (struct link_map *parent, const char *file, int mode) @@ -26,16 +30,83 @@ _dl_open (struct link_map *parent, const char *file, int mode) struct link_map *new, *l; ElfW(Addr) init; + /* Load the named object. */ - new = _dl_map_object (parent, file); + new = _dl_map_object (parent, file, lt_loaded); + if (new->l_searchlist) + /* It was already open. */ + return new; /* Load that object's dependencies. */ _dl_map_object_deps (new); - /* Relocate the objects loaded. */ - for (l = new; l; l = l->l_next) - if (! l->l_relocated) - _dl_relocate_object (l, (mode & RTLD_BINDING_MASK) == RTLD_LAZY); + + /* Relocate the objects loaded. We do this in reverse order so that copy + relocs of earlier objects overwrite the data written by later objects. */ + + l = new; + while (l->l_next) + l = l->l_next; + do + { + if (! l->l_relocated) + { + _dl_relocate_object (l, _dl_object_relocation_scope (l), + (mode & RTLD_BINDING_MASK) == RTLD_LAZY); + *_dl_global_scope_end = NULL; + } + + l = l->l_prev; + } while (l != new); + + new->l_global = (mode & RTLD_GLOBAL); + if (new->l_global) + { + /* The symbols of the new object and its dependencies are to be + introduced into the global scope that will be used to resolve + references from other dynamically-loaded objects. */ + + if (_dl_global_scope_alloc == 0) + { + /* This is the first dynamic object given global scope. */ + _dl_global_scope_alloc = 8; + _dl_global_scope = malloc (8 * sizeof (struct link_map *)); + if (! _dl_global_scope) + { + _dl_global_scope = _dl_default_scope; + nomem: + _dl_close (new); + _dl_signal_error (ENOMEM, file, "cannot extend global scope"); + } + _dl_global_scope[2] = _dl_default_scope[2]; + _dl_global_scope[3] = new; + _dl_global_scope[4] = NULL; + _dl_global_scope[5] = NULL; + } + else + { + if (_dl_global_scope_alloc < + _dl_global_scope_end - _dl_global_scope + 2) + { + /* Must extend the list. */ + struct link_map **new = realloc (_dl_global_scope, + _dl_global_scope_alloc * 2); + if (! new) + goto nomem; + _dl_global_scope_end = new + (_dl_global_scope_end - + _dl_global_scope); + _dl_global_scope = new; + _dl_global_scope_alloc *= 2; + } + + /* Append the new object and re-terminate the list. */ + *_dl_global_scope_end++ = new; + /* We keep the list double-terminated so the last element + can be filled in for symbol lookups. */ + _dl_global_scope_end[0] = NULL; + _dl_global_scope_end[1] = NULL; + } + } /* Run the initializer functions of new objects. */ while (init = _dl_init_next (new)) diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c index 5da8575da5..e6778e7de3 100644 --- a/elf/dl-reloc.c +++ b/elf/dl-reloc.c @@ -26,7 +26,7 @@ Cambridge, MA 02139, USA. */ void -_dl_relocate_object (struct link_map *l, int lazy) +_dl_relocate_object (struct link_map *l, struct link_map *scope[], int lazy) { if (l->l_relocated) return; @@ -52,44 +52,26 @@ _dl_relocate_object (struct link_map *l, int lazy) } { - struct link_map *scope[2]; + /* Do the actual relocation of the object's GOT and other data. */ - const char *strtab + const char *strtab /* String table object symbols. */ = ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr); - ElfW(Addr) resolve (const ElfW(Sym) **ref, ElfW(Addr) reloc_addr, int noplt) { + /* Look up the referenced symbol in the specified scope. */ return _dl_lookup_symbol (strtab + (*ref)->st_name, ref, scope, l->l_name, reloc_addr, noplt); } - if (l->l_info[DT_SYMBOLIC]) - { - scope[0] = l; - scope[1] = _dl_loaded; - } - else - { - scope[0] = _dl_loaded; - scope[1] = l; - } - - if (l->l_type == lt_interpreter) - /* We cannot be lazy when relocating the dynamic linker itself. It - was previously relocated eagerly (allowing us to be running now), - and needs always to be fully relocated so it can run without the - aid of run-time fixups (because it's the one to do them), so we - must always re-relocate its PLT eagerly. */ - lazy = 0; - ELF_DYNAMIC_RELOCATE (l, lazy, resolve); } - /* Set up the PLT so its unrelocated entries will - jump to _dl_runtime_resolve, which will relocate them. */ + /* Set up the PLT so its unrelocated entries will jump to + _dl_runtime_resolve (dl-runtime.c), which will relocate them. */ elf_machine_runtime_setup (l, lazy); + /* Mark the object so we know ths work has been done. */ l->l_relocated = 1; if (l->l_info[DT_TEXTREL]) @@ -114,5 +96,4 @@ _dl_relocate_object (struct link_map *l, int lazy) "can't restore segment prot after reloc"); } } - } diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c index c306543155..8ad2c0ffa4 100644 --- a/elf/dl-runtime.c +++ b/elf/dl-runtime.c @@ -20,6 +20,54 @@ Cambridge, MA 02139, USA. */ #include <link.h> #include "dynamic-link.h" + +/* The global scope we will use for symbol lookups. + This will be modified by _dl_open if RTLD_GLOBAL is used. */ +struct link_map **_dl_global_scope = _dl_default_scope; +struct link_map **_dl_global_scope_end = &_dl_default_scope[3]; + + +/* Hack _dl_global_scope[0] and [1] as necessary, and return a pointer into + _dl_global_scope that should be passed to _dl_lookup_symbol for symbol + references made in the object L's relocations. */ +inline struct link_map ** +_dl_object_relocation_scope (struct link_map *l) +{ + if (l->l_info[DT_SYMBOLIC]) + { + /* This object's global references are to be resolved first + in the object itself, and only secondarily in more global + scopes. */ + + if (! l->l_searchlist) + /* We must construct the searchlist for this object. */ + _dl_map_object_deps (l); + + /* The primary scope is this object itself and its + dependencies. */ + _dl_global_scope[0] = l; + + /* Secondary is the dependency tree that reached L; the object + requested directly by the user is at the root of that tree. */ + while (l->l_loader) + l = l->l_loader; + _dl_global_scope[1] = l; + + /* Finally, the global scope follows. */ + + return _dl_global_scope; + } + else + { + /* Use first the global scope, and then the scope of the root of the + dependency tree that first caused this object to be loaded. */ + while (l->l_loader) + l = l->l_loader; + *_dl_global_scope_end = l; + return &_dl_global_scope[2]; + } +} + /* Figure out the right type, Rel or Rela. */ #define elf_machine_rel 1 #define elf_machine_rela 2 @@ -67,17 +115,21 @@ fixup ( = (const void *) (l->l_addr + l->l_info[DT_JMPREL]->d_un.d_ptr + reloc_offset); + /* Set up the scope to find symbols referenced by this object. */ + struct link_map **scope = _dl_object_relocation_scope (l); + + /* Perform the specified relocation. */ ElfW(Addr) resolve (const ElfW(Sym) **ref, ElfW(Addr) reloc_addr, int noplt) { - struct link_map *scope[2] = { _dl_loaded, NULL }; return _dl_lookup_symbol (strtab + (*ref)->st_name, ref, scope, l->l_name, reloc_addr, noplt); } - - /* Perform the specified relocation. */ elf_machine_relplt (l, reloc, &symtab[ELFW(R_SYM) (reloc->r_info)], resolve); + *_dl_global_scope_end = NULL; + + /* Return the address that was written by the relocation. */ return *(ElfW(Addr) *) (l->l_addr + reloc->r_offset); } diff --git a/elf/dlclose.c b/elf/dlclose.c index 0d2689e01c..a5c8e7c17e 100644 --- a/elf/dlclose.c +++ b/elf/dlclose.c @@ -19,81 +19,13 @@ Cambridge, MA 02139, USA. */ #include <link.h> #include <dlfcn.h> -#include <stdlib.h> -#include <sys/types.h> -#include <sys/mman.h> - - -#define LOSE(s) _dl_signal_error (0, map->l_name, s) int dlclose (void *handle) { void doit (void) { - struct link_map *map = handle; - struct link_map **list; - unsigned int i; - - if (map->l_opencount == 0) - LOSE ("shared object not open"); - - /* Decrement the reference count. */ - if (--map->l_opencount > 0 || map->l_type != lt_loaded) - /* There are still references to this object. Do nothing more. */ - return; - - list = map->l_searchlist; - - /* The search list contains a counted reference to each object it - points to, the 0th elt being MAP itself. Decrement the reference - counts on all the objects MAP depends on. */ - for (i = 1; i < map->l_nsearchlist; ++i) - --list[i]->l_opencount; - - /* Clear the search list so it doesn't get freed while we are still - using it. We have cached it in LIST and will free it when - finished. */ - map->l_searchlist = NULL; - - /* Check each element of the search list to see if all references to - it are gone. */ - for (i = 0; i < map->l_nsearchlist; ++i) - { - struct link_map *map = list[i]; - if (map->l_opencount == 0 && map->l_type == lt_loaded) - { - /* That was the last reference, and this was a dlopen-loaded - object. We can unmap it. */ - const ElfW(Phdr) *ph; - - if (map->l_info[DT_FINI]) - /* Call its termination function. */ - (*(void (*) (void)) ((void *) map->l_addr + - map->l_info[DT_FINI]->d_un.d_ptr)) (); - - /* Unmap the segments. */ - for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph) - if (ph->p_type == PT_LOAD) - { - ElfW(Addr) mapstart = ph->p_vaddr & ~(ph->p_align - 1); - ElfW(Addr) mapend = ((ph->p_vaddr + ph->p_memsz - + ph->p_align - 1) - & ~(ph->p_align - 1)); - munmap ((caddr_t) mapstart, mapend - mapstart); - } - - /* Finally, unlink the data structure and free it. */ - map->l_prev->l_next = map->l_next; - if (map->l_next) - map->l_next->l_prev = map->l_prev; - if (map->l_searchlist) - free (map->l_searchlist); - free (map); - } - } - - free (list); + _dl_close (handle); } return _dlerror_run (doit) ? -1 : 0; diff --git a/elf/dlopen.c b/elf/dlopen.c index 74ab8bb715..e261fcadd9 100644 --- a/elf/dlopen.c +++ b/elf/dlopen.c @@ -28,7 +28,7 @@ dlopen (const char *file, int mode) void doit (void) { - new = _dl_open (_dl_loaded, file, mode); + new = _dl_open (_dl_loaded, file ?: "", mode); } return _dlerror_run (doit) ? NULL : new; diff --git a/elf/link.h b/elf/link.h index 6d284cbbde..89dfa2087f 100644 --- a/elf/link.h +++ b/elf/link.h @@ -106,6 +106,9 @@ struct link_map struct link_map **l_searchlist; unsigned int l_nsearchlist; + /* Dependent object that first caused this object to be loaded. */ + struct link_map *l_loader; + /* Symbol hash table. */ ElfW(Word) l_nbuckets; const ElfW(Word) *l_buckets, *l_chain; @@ -114,14 +117,14 @@ struct link_map enum /* Where this object came from. */ { lt_executable, /* The main executable program. */ - lt_interpreter, /* The interpreter: the dynamic linker. */ lt_library, /* Library needed by main executable. */ lt_loaded, /* Extra run-time loaded shared object. */ } l_type:2; unsigned int l_relocated:1; /* Nonzero if object's relocations done. */ unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */ unsigned int l_init_running:1; /* Nonzero while DT_INIT function runs. */ - unsigned int l_reserved:3; /* Reserved for internal use. */ + unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */ + unsigned int l_reserved:2; /* Reserved for internal use. */ }; /* Internal functions of the run-time dynamic linker. @@ -188,12 +191,7 @@ extern int _dlerror_run (void (*operate) (void)); LOADER's DT_RPATH is used in searching for NAME. If the object is already opened, returns its existing map. */ extern struct link_map *_dl_map_object (struct link_map *loader, - const char *name); - -/* Similar, but file found at REALNAME and opened on FD. - REALNAME must malloc'd storage and is used in internal data structures. */ -extern struct link_map *_dl_map_object_from_fd (const char *name, - int fd, char *realname); + const char *name, int type); /* Call _dl_map_object on the dependencies of MAP, and set up MAP->l_searchlist. */ @@ -210,21 +208,24 @@ extern void _dl_setup_hash (struct link_map *map); extern struct link_map *_dl_open (struct link_map *loader, const char *name, int mode); +/* Close an object previously opened by _dl_open. */ +extern void _dl_close (struct link_map *map); /* Search loaded objects' symbol tables for a definition of the symbol referred to by UNDEF. *SYM is the symbol table entry containing the reference; it is replaced with the defining symbol, and the base load - address of the defining object is returned. Each of SYMBOL_SCOPE[0] and - SYMBOL_SCOPE[1] that is not null and their dependencies are searched to - resolve the name. REFERENCE_NAME should name the object containing the - reference; it is used in error messages. RELOC_ADDR is the address - being fixed up and the chosen symbol cannot be one with this value. If - NOPLT is nonzero, then the reference must not be resolved to a PLT - entry. */ + address of the defining object is returned. SYMBOL_SCOPE is a + null-terminated list of object scopes to search; each object's + l_searchlist (i.e. the segment of the dependency tree starting at that + object) is searched in turn. REFERENCE_NAME should name the object + containing the reference; it is used in error messages. RELOC_ADDR is + the address being fixed up and the chosen symbol cannot be one with this + value. If NOPLT is nonzero, then the reference must not be resolved to + a PLT entry. */ extern ElfW(Addr) _dl_lookup_symbol (const char *undef, const ElfW(Sym) **sym, - struct link_map *symbol_scope[2], + struct link_map *symbol_scope[], const char *reference_name, ElfW(Addr) reloc_addr, int noplt); @@ -236,11 +237,33 @@ extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name); /* Structure describing the dynamic linker itself. */ extern struct link_map _dl_rtld_map; -/* List of objects currently loaded. */ -extern struct link_map *_dl_loaded; +/* The list of objects currently loaded is the third element of the + `_dl_default_scope' array, and the fourth element is always null. + This leaves two slots before it that are used when resolving + DT_SYMBOLIC objects' references one after it for normal references + (see below). */ +#define _dl_loaded (_dl_default_scope[2]) +extern struct link_map *_dl_default_scope[5]; + +/* Null-terminated list of objects in the dynamic `global scope'. The + list starts at [2]; i.e. &_dl_global_scope[2] is the argument + passed to _dl_lookup_symbol to search the global scope. To search + a specific object and its dependencies in preference to the global + scope, fill in the [1] slot and pass its address; for two specific + object scopes, fill [0] and [1]. The list is double-terminated; to + search the global scope and then a specific object and its + dependencies, set *_dl_global_scope_end. This variable initially + points to _dl_default_scope, and _dl_loaded is always kept in [2] + of this list. A new list is malloc'd when new objects are loaded + with RTLD_GLOBAL. */ +extern struct link_map **_dl_global_scope, **_dl_global_scope_end; +extern size_t _dl_global_scope_alloc; /* Number of slots malloc'd. */ + +/* Hack _dl_global_scope[0] and [1] as necessary, and return a pointer into + _dl_global_scope that should be passed to _dl_lookup_symbol for symbol + references made in the object MAP's relocations. */ +extern struct link_map **_dl_object_relocation_scope (struct link_map *map); -/* Tail of that list which were loaded at startup. */ -extern struct link_map *_dl_startup_loaded; /* Allocate a `struct link_map' for a new object being loaded, and enter it into the _dl_loaded list. */ @@ -248,8 +271,11 @@ extern struct link_map *_dl_new_object (char *realname, const char *libname, int type); /* Relocate the given object (if it hasn't already been). + SCOPE is passed to _dl_lookup_symbol in symbol lookups. If LAZY is nonzero, don't relocate its PLT. */ -extern void _dl_relocate_object (struct link_map *map, int lazy); +extern void _dl_relocate_object (struct link_map *map, + struct link_map *scope[], + int lazy); /* Return the address of the next initializer function for MAP or one of its dependencies that has not yet been run. When there are no more diff --git a/elf/rtld.c b/elf/rtld.c index bc1f71bd4e..66477274e5 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -75,13 +75,6 @@ _dl_start (void *arg) /* Relocate ourselves so we can do normal function calls and data access using the global offset table. */ - /* We must initialize `l_type' to make sure it is not `lt_interpreter'. - That is the type to describe us, but not during bootstrapping--it - indicates to elf_machine_rel{,a} that we were already relocated during - bootstrapping, so it must anti-perform each bootstrapping relocation - before applying the final relocation when ld.so is linked in as - normal a shared library. */ - bootstrap_map.l_type = lt_library; ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, NULL); @@ -178,7 +171,7 @@ of this helper program; chances are you did not intend to run this program.\n", --_dl_argc; ++_dl_argv; - l = _dl_map_object (NULL, _dl_argv[0]); + l = _dl_map_object (NULL, _dl_argv[0], lt_library); phdr = l->l_phdr; phent = l->l_phnum; l->l_name = (char *) ""; @@ -188,7 +181,7 @@ of this helper program; chances are you did not intend to run this program.\n", { /* Create a link_map for the executable itself. This will be what dlopen on "" returns. */ - l = _dl_new_object ((char *) "", "", lt_executable); + l = _dl_new_object ((char *) "", "", lt_library); l->l_phdr = phdr; l->l_phnum = phent; interpreter_name = 0; @@ -245,7 +238,7 @@ of this helper program; chances are you did not intend to run this program.\n", /* Put the link_map for ourselves on the chain so it can be found by name. */ _dl_rtld_map.l_name = (char *) _dl_rtld_map.l_libname = interpreter_name; - _dl_rtld_map.l_type = lt_interpreter; + _dl_rtld_map.l_type = lt_library; while (l->l_next) l = l->l_next; l->l_next = &_dl_rtld_map; @@ -293,9 +286,9 @@ of this helper program; chances are you did not intend to run this program.\n", for (i = 1; i < _dl_argc; ++i) { const ElfW(Sym) *ref = NULL; - struct link_map *scope[2] ={ _dl_loaded, NULL }; - ElfW(Addr) loadbase - = _dl_lookup_symbol (_dl_argv[i], &ref, scope, "argument", 0, 0); + ElfW(Addr) loadbase = _dl_lookup_symbol (_dl_argv[i], &ref, + &_dl_default_scope[2], + "argument", 0, 0); char buf[20], *bp; buf[sizeof buf - 1] = '\0'; bp = _itoa (ref->st_value, &buf[sizeof buf - 1], 16, 0); @@ -314,35 +307,41 @@ of this helper program; chances are you did not intend to run this program.\n", lazy = !_dl_secure && *(getenv ("LD_BIND_NOW") ?: "") == '\0'; - /* Now we have all the objects loaded. Relocate them all except for - the dynamic linker itself. We do this in reverse order so that - copy relocs of earlier objects overwrite the data written by later - objects. We do not re-relocate the dynamic linker itself in this - loop because that could result in the GOT entries for functions we - call being changed, and that would break us. It is safe to - relocate the dynamic linker out of order because it has no copy - relocs (we know that because it is self-contained). */ - l = _dl_loaded; - while (l->l_next) - l = l->l_next; - do - { - if (l != &_dl_rtld_map) - _dl_relocate_object (l, lazy); - l = l->l_prev; - } while (l); - - /* Do any necessary cleanups for the startup OS interface code. - We do these now so that no calls are made after rtld re-relocation - which might be resolved to different functions than we expect. - We cannot do this before relocating the other objects because - _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */ - _dl_sysdep_start_cleanup (); - - if (_dl_rtld_map.l_opencount > 0) - /* There was an explicit ref to the dynamic linker as a shared lib. - Re-relocate ourselves with user-controlled symbol definitions. */ - _dl_relocate_object (&_dl_rtld_map, lazy); + { + /* Now we have all the objects loaded. Relocate them all except for + the dynamic linker itself. We do this in reverse order so that copy + relocs of earlier objects overwrite the data written by later + objects. We do not re-relocate the dynamic linker itself in this + loop because that could result in the GOT entries for functions we + call being changed, and that would break us. It is safe to relocate + the dynamic linker out of order because it has no copy relocs (we + know that because it is self-contained). */ + + l = _dl_loaded; + while (l->l_next) + l = l->l_next; + do + { + if (l != &_dl_rtld_map) + { + _dl_relocate_object (l, _dl_object_relocation_scope (l), lazy); + *_dl_global_scope_end = NULL; + } + l = l->l_prev; + } while (l); + + /* Do any necessary cleanups for the startup OS interface code. + We do these now so that no calls are made after rtld re-relocation + which might be resolved to different functions than we expect. + We cannot do this before relocating the other objects because + _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */ + _dl_sysdep_start_cleanup (); + + if (_dl_rtld_map.l_opencount > 0) + /* There was an explicit ref to the dynamic linker as a shared lib. + Re-relocate ourselves with user-controlled symbol definitions. */ + _dl_relocate_object (&_dl_rtld_map, &_dl_default_scope[2], 0); + } /* Tell the debugger where to find the map of loaded objects. */ _dl_r_debug.r_version = 1 /* R_DEBUG_VERSION XXX */; |