diff options
Diffstat (limited to 'elf/rtld.c')
| -rw-r--r-- | elf/rtld.c | 268 |
1 files changed, 132 insertions, 136 deletions
diff --git a/elf/rtld.c b/elf/rtld.c index fd75779a01..0605336603 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -52,40 +52,33 @@ static void dl_main (const Elf32_Phdr *phdr, Elf32_Addr _dl_start (void *arg) { - Elf32_Addr rtld_loadaddr; - Elf32_Dyn *dynamic_section; - Elf32_Dyn *dynamic_info[DT_NUM]; + struct link_map rtld_map; /* Figure out the run-time load address of the dynamic linker itself. */ - rtld_loadaddr = elf_machine_load_address (); + rtld_map.l_addr = elf_machine_load_address (); /* Read our own dynamic section and fill in the info array. Conveniently, the first element of the GOT contains the offset of _DYNAMIC relative to the run-time load address. */ - dynamic_section = (void *) rtld_loadaddr + *elf_machine_got (); - elf_get_dynamic_info (dynamic_section, dynamic_info); + rtld_map.l_ld = (void *) rtld_map.l_addr + *elf_machine_got (); + elf_get_dynamic_info (rtld_map.l_ld, rtld_map.l_info); #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC - ELF_MACHINE_BEFORE_RTLD_RELOC (dynamic_info); + ELF_MACHINE_BEFORE_RTLD_RELOC (rtld_map.l_info); #endif /* Relocate ourselves so we can do normal function calls and data access using the global offset table. */ - { - Elf32_Addr resolve (const Elf32_Sym **ref) - { - assert ((*ref)->st_shndx != SHN_UNDEF); - return rtld_loadaddr; - } - elf_dynamic_relocate (dynamic_info, rtld_loadaddr, 0, resolve); - } + + ELF_DYNAMIC_RELOCATE (&rtld_map, 0, NULL); + /* Now life is sane; we can call functions and access global data. Set up to use the operating system facilities, and find out from the operating system's program loader where to find the program header table in core. */ - dl_r_debug.r_ldbase = rtld_loadaddr; /* Record our load address. */ + dl_r_debug.r_ldbase = rtld_map.l_addr; /* Record our load address. */ /* Call the OS-dependent function to set up life so we can do things like file access. It will call `dl_main' (below) to do all the real work @@ -107,29 +100,30 @@ dl_main (const Elf32_Phdr *phdr, { void doit (void) { - const Elf32_Phdr *ph; - struct link_map *l; - const char *interpreter_name; - int lazy; + const Elf32_Phdr *ph; + struct link_map *l; + const char *interpreter_name; + int lazy; - if (*user_entry == (Elf32_Addr) &_start) - { - /* Ho ho. We are not the program interpreter! We are the program - itself! This means someone ran ld.so as a command. Well, that - might be convenient to do sometimes. We support it by - interpreting the args like this: - - ld.so PROGRAM ARGS... - - The first argument is the name of a file containing an ELF - executable we will load and run with the following arguments. To - simplify life here, PROGRAM is searched for using the normal rules - for shared objects, rather than $PATH or anything like that. We - just load it and use its entry point; we don't pay attention to - its PT_INTERP command (we are the interpreter ourselves). This is - an easy way to test a new ld.so before installing it. */ - if (_dl_argc < 2) - _dl_sysdep_fatal ("\ + if (*user_entry == (Elf32_Addr) &_start) + { + /* Ho ho. We are not the program interpreter! We are the program + itself! This means someone ran ld.so as a command. Well, that + might be convenient to do sometimes. We support it by + interpreting the args like this: + + ld.so PROGRAM ARGS... + + The first argument is the name of a file containing an ELF + executable we will load and run with the following arguments. + To simplify life here, PROGRAM is searched for using the + normal rules for shared objects, rather than $PATH or anything + like that. We just load it and use its entry point; we don't + pay attention to its PT_INTERP command (we are the interpreter + ourselves). This is an easy way to test a new ld.so before + installing it. */ + if (_dl_argc < 2) + _dl_sysdep_fatal ("\ Usage: ld.so EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\ You have invoked `ld.so', the helper program for shared library executables.\n\ This program usually lives in the file `/lib/ld.so', and special directives\n\ @@ -142,116 +136,118 @@ that file itself, but always uses this helper program from the file you\n\ specified, instead of the helper program file specified in the executable\n\ file you run. This is mostly of use for maintainers to test new versions\n\ of this helper program; chances are you did not intend to run this program.\n" - ); - - interpreter_name = _dl_argv[0]; - --_dl_argc; - ++_dl_argv; - l = _dl_map_object (NULL, _dl_argv[0], user_entry); - phdr = l->l_phdr; - phent = l->l_phnum; - l->l_type = lt_executable; - l->l_libname = (char *) ""; - } - else - { - /* Create a link_map for the executable itself. - This will be what dlopen on "" returns. */ - l = _dl_new_object ((char *) "", "", lt_executable); - l->l_phdr = phdr; - l->l_phnum = phent; - interpreter_name = 0; - } + ); + + interpreter_name = _dl_argv[0]; + --_dl_argc; + ++_dl_argv; + l = _dl_map_object (NULL, _dl_argv[0], user_entry); + phdr = l->l_phdr; + phent = l->l_phnum; + l->l_type = lt_executable; + l->l_libname = (char *) ""; + } + else + { + /* Create a link_map for the executable itself. + This will be what dlopen on "" returns. */ + l = _dl_new_object ((char *) "", "", lt_executable); + l->l_phdr = phdr; + l->l_phnum = phent; + interpreter_name = 0; + } - /* Scan the program header table for the dynamic section. */ - for (ph = phdr; ph < &phdr[phent]; ++ph) - switch (ph->p_type) - { - case PT_DYNAMIC: - /* This tells us where to find the dynamic section, - which tells us everything we need to do. */ - l->l_ld = (void *) ph->p_vaddr; - break; - case PT_INTERP: - /* This "interpreter segment" was used by the program loader to - find the program interpreter, which is this program itself, the - dynamic linker. We note what name finds us, so that a future - dlopen call or DT_NEEDED entry, for something that wants to link - against the dynamic linker as a shared library, will know that - the shared object is already loaded. */ - interpreter_name = (void *) ph->p_vaddr; - break; - } - assert (interpreter_name); /* How else did we get here? */ - - /* Extract the contents of the dynamic section for easy access. */ - elf_get_dynamic_info (l->l_ld, l->l_info); - /* Set up our cache of pointers into the hash table. */ - _dl_setup_hash (l); - - if (l->l_info[DT_DEBUG]) - /* There is a DT_DEBUG entry in the dynamic section. Fill it in - with the run-time address of the r_debug structure, which we - will set up later to communicate with the debugger. */ - l->l_info[DT_DEBUG]->d_un.d_ptr = (Elf32_Addr) &dl_r_debug; - - l = _dl_new_object ((char *) interpreter_name, interpreter_name, - lt_interpreter); - - /* Now process all the DT_NEEDED entries and map in the objects. - Each new link_map will go on the end of the chain, so we will - come across it later in the loop to map in its dependencies. */ - for (l = _dl_loaded; l; l = l->l_next) - { - if (l->l_info[DT_NEEDED]) + /* Scan the program header table for the dynamic section. */ + for (ph = phdr; ph < &phdr[phent]; ++ph) + switch (ph->p_type) + { + case PT_DYNAMIC: + /* This tells us where to find the dynamic section, + which tells us everything we need to do. */ + l->l_ld = (void *) ph->p_vaddr; + break; + case PT_INTERP: + /* This "interpreter segment" was used by the program loader to + find the program interpreter, which is this program itself, the + dynamic linker. We note what name finds us, so that a future + dlopen call or DT_NEEDED entry, for something that wants to link + against the dynamic linker as a shared library, will know that + the shared object is already loaded. */ + interpreter_name = (void *) ph->p_vaddr; + break; + } + assert (interpreter_name); /* How else did we get here? */ + + /* Extract the contents of the dynamic section for easy access. */ + elf_get_dynamic_info (l->l_ld, l->l_info); + /* Set up our cache of pointers into the hash table. */ + _dl_setup_hash (l); + + if (l->l_info[DT_DEBUG]) + /* There is a DT_DEBUG entry in the dynamic section. Fill it in + with the run-time address of the r_debug structure, which we + will set up later to communicate with the debugger. */ + l->l_info[DT_DEBUG]->d_un.d_ptr = (Elf32_Addr) &dl_r_debug; + + l = _dl_new_object ((char *) interpreter_name, interpreter_name, + lt_interpreter); + + /* Now process all the DT_NEEDED entries and map in the objects. + Each new link_map will go on the end of the chain, so we will + come across it later in the loop to map in its dependencies. */ + for (l = _dl_loaded; l; l = l->l_next) { - const char *strtab - = (void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr; - const Elf32_Dyn *d; - for (d = l->l_ld; d->d_tag != DT_NULL; ++d) - if (d->d_tag == DT_NEEDED) - _dl_map_object (l, strtab + d->d_un.d_val, NULL); + if (l->l_info[DT_NEEDED]) + { + const char *strtab + = (void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr; + const Elf32_Dyn *d; + for (d = l->l_ld; d->d_tag != DT_NULL; ++d) + if (d->d_tag == DT_NEEDED) + _dl_map_object (l, strtab + d->d_un.d_val, NULL); + } + l->l_deps_loaded = 1; } - l->l_deps_loaded = 1; - } - l = _dl_loaded->l_next; - assert (l->l_type == lt_interpreter); - if (l->l_opencount == 0) - { - /* No DT_NEEDED entry referred to the interpreter object itself. - Remove it from the maps we will use for symbol resolution. */ - l->l_prev->l_next = l->l_next; - if (l->l_next) - l->l_next->l_prev = l->l_prev; - } + l = _dl_loaded->l_next; + assert (l->l_type == lt_interpreter); + if (l->l_opencount == 0) + { + /* No DT_NEEDED entry referred to the interpreter object itself. + Remove it from the maps we will use for symbol resolution. */ + l->l_prev->l_next = l->l_next; + if (l->l_next) + l->l_next->l_prev = l->l_prev; + } - lazy = _dl_secure || *(getenv ("LD_BIND_NOW") ?: ""); + lazy = _dl_secure || *(getenv ("LD_BIND_NOW") ?: ""); - /* Now we have all the objects loaded. Relocate them all. - We do this in reverse order so that copy relocs of earlier - objects overwrite the data written by later objects. */ - l = _dl_loaded; - while (l->l_next) - l = l->l_next; - do - { - _dl_relocate_object (l, lazy); - l = l->l_prev; - } while (l); - - /* Tell the debugger where to find the map of loaded objects. */ - dl_r_debug.r_version = 1 /* R_DEBUG_VERSION XXX */; - dl_r_debug.r_map = _dl_loaded; - dl_r_debug.r_brk = (Elf32_Addr) &_dl_r_debug_state; -} + /* Now we have all the objects loaded. Relocate them all. + We do this in reverse order so that copy relocs of earlier + objects overwrite the data written by later objects. */ + l = _dl_loaded; + while (l->l_next) + l = l->l_next; + do + { + _dl_relocate_object (l, lazy); + l = l->l_prev; + } while (l); + + /* Tell the debugger where to find the map of loaded objects. */ + dl_r_debug.r_version = 1 /* R_DEBUG_VERSION XXX */; + dl_r_debug.r_map = _dl_loaded; + dl_r_debug.r_brk = (Elf32_Addr) &_dl_r_debug_state; + } const char *errstring; + const char *errobj; int err; - err = _dl_catch_error (&errstring, &doit); + err = _dl_catch_error (&errstring, &errobj, &doit); if (errstring) _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>", ": error in loading shared libraries\n", + errobj ?: "", errobj ? ": " : "", errstring, err ? ": " : NULL, err ? strerror (err) : NULL, NULL); |