From: H. Peter Anvin Date: Fri, 18 Jan 2013 00:52:20 +0000 (-0800) Subject: elf: remove long-since-obsolete shallow module machinery X-Git-Tag: syslinux-5.01-pre4~9 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=14fe8af6c11e71619de9be1afd4556ebbc770db3;p=platform%2Fupstream%2Fsyslinux.git elf: remove long-since-obsolete shallow module machinery Meant to handle symbols exported from the core, but we just pregenerate the dynamic section instead. Signed-off-by: H. Peter Anvin --- diff --git a/com32/include/sys/exec.h b/com32/include/sys/exec.h index ac05c27..f4559d1 100644 --- a/com32/include/sys/exec.h +++ b/com32/include/sys/exec.h @@ -34,27 +34,6 @@ extern int spawn_load(const char *name, int argc, char **argv); /** - * exec_init - Initialize the dynamic execution environment. - * - * Among others, it initializes the module subsystem and loads the root - * module into memory. You should note the difference between the module - * management API, and the execution API: - * - the module system is a static one - it only manages the data structures - * and their relationship. It does not describe the way modules are executed, - * when and how they are loaded/unloaded, etc. It acts as a service layer for - * the execution API. - * - the execution environment is the dynamic part of the SYSLINUX dynamic - * module API - it implements the behavior of the modules: it - * triggers the execution of initialization and termination functions for - * libraries, executes the modules marked as executable, handles dynamic - * memory cleanup, etc. In other words, at this layer the code and data - * loaded by the lower module layer gets to be executed by the CPU, - * thus becoming part of the SYSLINUX environment. - */ -extern int exec_init(void); - - -/** * spawnv - Executes a program in the current environment. * @name: the name of the program to spawn, including the extension * (e.g. 'hello.c32') diff --git a/com32/include/sys/module.h b/com32/include/sys/module.h index ea11a88..a18561a 100644 --- a/com32/include/sys/module.h +++ b/com32/include/sys/module.h @@ -246,18 +246,6 @@ extern int module_load(struct elf_module *module); /** - * module_load_shallow - loads a shallow ELF module into memory. - * @module: the module descriptor returned by module_alloc. - * - * The function reads the module file, checks whether the file has a valid - * structure, then loads into memory the module metadata. The metadata currently - * contains a symbol table that describes code & data allocated by other means. - * Its current use is to describe the root COM32 module to the rest of the - * module subsystem. - */ -extern int module_load_shallow(struct elf_module *module, Elf32_Addr base_addr); - -/** * module_unload - unloads the module from the system. * @module: the module descriptor structure. * diff --git a/com32/lib/Makefile b/com32/lib/Makefile index dd1ef7c..d979ab4 100644 --- a/com32/lib/Makefile +++ b/com32/lib/Makefile @@ -86,7 +86,7 @@ LIBENTRY_OBJS = \ LIBMODULE_OBJS = \ sys/module/common.o sys/module/elf_module.o \ - sys/module/shallow_module.o sys/module/elfutils.o \ + sys/module/elfutils.o \ sys/module/exec.o LIBGCC_OBJS = \ diff --git a/com32/lib/sys/module/exec.c b/com32/lib/sys/module/exec.c index ac9ca79..2b3a4c0 100644 --- a/com32/lib/sys/module/exec.c +++ b/com32/lib/sys/module/exec.c @@ -18,32 +18,8 @@ #define DBG_PRINT(fmt, args...) dprintf("[EXEC] " fmt, ##args) -static struct elf_module *mod_root = NULL; struct elf_module *__syslinux_current = NULL; -int exec_init(void) -{ - int res; - - res = modules_init(); - if (res != 0) - return res; - - // Load the root module - mod_root = module_alloc(EXEC_ROOT_NAME); - - if (mod_root == NULL) - return -1; - - res = module_load_shallow(mod_root, 0); - if (res != 0) { - mod_root = NULL; - return res; - } - - return 0; -} - int get_module_type(struct elf_module *module) { if(module->main_func) return EXEC_MODULE; diff --git a/com32/lib/sys/module/shallow_module.c b/com32/lib/sys/module/shallow_module.c deleted file mode 100644 index 8a88e40..0000000 --- a/com32/lib/sys/module/shallow_module.c +++ /dev/null @@ -1,161 +0,0 @@ -/* - * shallow_module.c - * - * Created on: Aug 11, 2008 - * Author: Stefan Bucur - */ - - -#include -#include - -#include "common.h" -#include "elfutils.h" - - -static int check_header_shallow(Elf32_Ehdr *elf_hdr) { - int res; - - res = check_header_common(elf_hdr); - - if (res != 0) - return res; - - if (elf_hdr->e_shoff == 0x00000000) { - DBG_PRINT("SHT missing\n"); - return -1; - } - - return 0; -} - -static int load_shallow_sections(struct elf_module *module, Elf32_Ehdr *elf_hdr) { - int i; - int res = 0; - char *sht = NULL; - char *buffer = NULL; - Elf32_Shdr *crt_sht; - Elf32_Off buff_offset; - - Elf32_Off min_offset = 0xFFFFFFFF; - Elf32_Off max_offset = 0x00000000; - Elf32_Word max_align = 0x1; - - Elf32_Off sym_offset = 0xFFFFFFFF; - Elf32_Off str_offset = 0xFFFFFFFF; - - - char *sh_strtable; - - // We buffer the data up to the SHT - buff_offset = module->u.l._cr_offset; - - buffer = malloc(elf_hdr->e_shoff - buff_offset); - // Get to the SHT - image_read(buffer, elf_hdr->e_shoff - buff_offset, module); - - // Load the SHT - sht = malloc(elf_hdr->e_shnum * elf_hdr->e_shentsize); - image_read(sht, elf_hdr->e_shnum * elf_hdr->e_shentsize, module); - - // Get the string table of the section names - crt_sht = (Elf32_Shdr*)(sht + elf_hdr->e_shstrndx * elf_hdr->e_shentsize); - sh_strtable = (char*)(buffer + (crt_sht->sh_offset - buff_offset)); - - for (i = 0; i < elf_hdr->e_shnum; i++) { - crt_sht = (Elf32_Shdr*)(sht + i*elf_hdr->e_shentsize); - - if (strcmp(".symtab", sh_strtable + crt_sht->sh_name) == 0) { - // We found the symbol table - min_offset = MIN(min_offset, crt_sht->sh_offset); - max_offset = MAX(max_offset, crt_sht->sh_offset + crt_sht->sh_size); - max_align = MAX(max_align, crt_sht->sh_addralign); - - sym_offset = crt_sht->sh_offset; - - module->syment_size = crt_sht->sh_entsize; - module->symtable_size = crt_sht->sh_size / crt_sht->sh_entsize; - } - if (strcmp(".strtab", sh_strtable + crt_sht->sh_name) == 0) { - // We found the string table - min_offset = MIN(min_offset, crt_sht->sh_offset); - max_offset = MAX(max_offset, crt_sht->sh_offset + crt_sht->sh_size); - max_align = MAX(max_align, crt_sht->sh_addralign); - - str_offset = crt_sht->sh_offset; - - module->strtable_size = crt_sht->sh_size; - } - } - - if (elf_malloc(&module->module_addr, max_align, - max_offset - min_offset) != 0) { - DBG_PRINT("Could not allocate sections\n"); - goto out; - } - - // Copy the data - image_seek(min_offset, module); - image_read(module->module_addr, max_offset - min_offset, module); - - // Setup module information - module->module_size = max_offset - min_offset; - module->str_table = (char *)module->module_addr + (str_offset - min_offset); - module->sym_table = (char *)module->module_addr + (sym_offset - min_offset); - -out: - // Release the SHT - if (sht != NULL) - free(sht); - - // Release the buffer - if (buffer != NULL) - free(buffer); - - return res; -} - - -int module_load_shallow(struct elf_module *module, Elf32_Addr base_addr) { - int res; - Elf32_Ehdr elf_hdr; - - // Do not allow duplicate modules - if (module_find(module->name) != NULL) { - DBG_PRINT("Module already loaded.\n"); - return -1; - } - - res = image_load(module); - - if (res < 0) - return res; - - module->shallow = 1; - - CHECKED(res, image_read(&elf_hdr, sizeof(Elf32_Ehdr), module), error); - - // Checking the header signature and members - CHECKED(res, check_header_shallow(&elf_hdr), error); - - CHECKED(res, load_shallow_sections(module, &elf_hdr), error); - module->base_addr = base_addr; - - // Check the symbols for duplicates / missing definitions - CHECKED(res, check_symbols(module), error); - - // Add the module at the beginning of the module list - list_add(&module->list, &modules_head); - - // The file image is no longer needed - image_unload(module); - - DBG_PRINT("SHALLOW MODULE %s LOADED SUCCESSFULLY\n", module->name); - - return 0; - -error: - image_unload(module); - - return res; -} diff --git a/core/elflink/load_env32.c b/core/elflink/load_env32.c index 7c0afac..7a6b08f 100644 --- a/core/elflink/load_env32.c +++ b/core/elflink/load_env32.c @@ -50,10 +50,10 @@ struct elf_module core_module = { }; /* - Initializes the module subsystem by taking the core module ( shallow module ) and placing - it on top of the modules_head_list. Since the core module is initialized when declared - we technically don't need the exec_init() and module_load_shallow() procedures -*/ + * Initializes the module subsystem by taking the core module + * (preinitialized shallow module) and placing it on top of the + * modules_head_list. + */ void init_module_subsystem(struct elf_module *module) { list_add(&module->list, &modules_head);