From e1de3af9892a89156c109befa13403359ee8568f Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Sun, 29 Mar 2009 16:38:59 +0000 Subject: module loading for 2.4: use fd-based io instead of FILE based; use xlseek and xread; simpler check for ELF signature. text data bss dec hex filename 824460 476 7616 832552 cb428 busybox_old 824333 476 7616 832425 cb3a9 busybox_unstripped --- modutils/modutils-24.c | 62 ++++++++++++++++++++++---------------------------- 1 file changed, 27 insertions(+), 35 deletions(-) (limited to 'modutils/modutils-24.c') diff --git a/modutils/modutils-24.c b/modutils/modutils-24.c index 169fe54ae..89bc30fe5 100644 --- a/modutils/modutils-24.c +++ b/modutils/modutils-24.c @@ -625,7 +625,7 @@ static unsigned long obj_load_size(struct obj_file *f); static int obj_relocate(struct obj_file *f, ElfW(Addr) base); -static struct obj_file *obj_load(FILE *f, int loadprogbits); +static struct obj_file *obj_load(int fd, int loadprogbits); static int obj_create_image(struct obj_file *f, char *image); @@ -3191,8 +3191,13 @@ static int obj_create_image(struct obj_file *f, char *image) /*======================================================================*/ -static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM) +static struct obj_file *obj_load(int fd, int loadprogbits UNUSED_PARAM) { +#if BB_LITTLE_ENDIAN +# define ELFMAG_U32 ((uint32_t)(ELFMAG0 + 0x100 * (ELFMAG1 + (0x100 * (ELFMAG2 + 0x100 * ELFMAG3))))) +#else +# define ELFMAG_U32 ((uint32_t)((((ELFMAG0 * 0x100) + ELFMAG1) * 0x100 + ELFMAG2) * 0x100 + ELFMAG3)) +#endif struct obj_file *f; ElfW(Shdr) * section_headers; size_t shnum, i; @@ -3205,16 +3210,10 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM) f->symbol_hash = obj_elf_hash; f->load_order_search_start = &f->load_order; - fseek(fp, 0, SEEK_SET); - if (fread(&f->header, sizeof(f->header), 1, fp) != 1) { - bb_perror_msg_and_die("error reading ELF header"); - } + xlseek(fd, 0, SEEK_SET); + xread(fd, &f->header, sizeof(f->header)); - if (f->header.e_ident[EI_MAG0] != ELFMAG0 - || f->header.e_ident[EI_MAG1] != ELFMAG1 - || f->header.e_ident[EI_MAG2] != ELFMAG2 - || f->header.e_ident[EI_MAG3] != ELFMAG3 - ) { + if (*(uint32_t*)(&f->header.e_ident) != ELFMAG_U32) { bb_error_msg_and_die("not an ELF file"); } if (f->header.e_ident[EI_CLASS] != ELFCLASSM @@ -3243,10 +3242,8 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM) f->sections = xzalloc(sizeof(f->sections[0]) * (shnum + 4)); section_headers = alloca(sizeof(ElfW(Shdr)) * shnum); - fseek(fp, f->header.e_shoff, SEEK_SET); - if (fread(section_headers, sizeof(ElfW(Shdr)), shnum, fp) != shnum) { - bb_perror_msg_and_die("error reading ELF section headers"); - } + xlseek(fd, f->header.e_shoff, SEEK_SET); + xread(fd, section_headers, sizeof(ElfW(Shdr)) * shnum); /* Read the section data. */ @@ -3278,10 +3275,8 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM) sec->contents = NULL; if (sec->header.sh_size > 0) { sec->contents = xmalloc(sec->header.sh_size); - fseek(fp, sec->header.sh_offset, SEEK_SET); - if (fread(sec->contents, sec->header.sh_size, 1, fp) != 1) { - bb_perror_msg_and_die("error reading ELF section data"); - } + xlseek(fd, sec->header.sh_offset, SEEK_SET); + xread(fd, sec->contents, sec->header.sh_size); } break; #if SHT_RELM == SHT_REL @@ -3397,27 +3392,24 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM) * kernel for the module */ -static int obj_load_progbits(FILE *fp, struct obj_file *f, char *imagebase) +static int obj_load_progbits(int fd, struct obj_file *f, char *imagebase) { ElfW(Addr) base = f->baseaddr; struct obj_section* sec; for (sec = f->load_order; sec; sec = sec->load_next) { - /* section already loaded? */ if (sec->contents != NULL) continue; - if (sec->header.sh_size == 0) continue; - sec->contents = imagebase + (sec->header.sh_addr - base); - fseek(fp, sec->header.sh_offset, SEEK_SET); - if (fread(sec->contents, sec->header.sh_size, 1, fp) != 1) { + xlseek(fd, sec->header.sh_offset, SEEK_SET); + errno = 0; /* read may be short without errno being set */ + if (full_read(fd, sec->contents, sec->header.sh_size) != sec->header.sh_size) { bb_perror_msg("error reading ELF section data"); return 0; } - } return 1; } @@ -3779,22 +3771,23 @@ int FAST_FUNC bb_init_module_24(const char *m_filename, const char *options) struct utsname uts; int exit_status = EXIT_FAILURE; int m_has_modinfo; - char *m_name; + char *m_name, *p; #if ENABLE_FEATURE_INSMOD_VERSION_CHECKING char m_strversion[STRVERSIONLEN]; int m_version, m_crcs; #endif - FILE *fp; + int fd; uname(&uts); - fp = fopen_for_read(m_filename); - if (fp == NULL) + fd = open_or_warn(m_filename, O_RDONLY); + if (fd < 0) return EXIT_FAILURE; m_name = xstrdup(bb_basename(m_filename)); - *strrchr(m_name, '.') = 0; + p = strrchr(m_name, '.'); + if (p) *p = '\0'; - f = obj_load(fp, LOADBITS); + f = obj_load(fd, LOADBITS); m_has_modinfo = (get_modinfo_value(f, "kernel_version") != NULL); @@ -3876,7 +3869,7 @@ int FAST_FUNC bb_init_module_24(const char *m_filename, const char *options) * the PROGBITS section was not loaded by the obj_load * now we can load them directly into the kernel memory */ - if (!obj_load_progbits(fp, f, (char*)m_addr)) { + if (!obj_load_progbits(fd, f, (char*)m_addr)) { delete_module(m_name, 0); goto out; } @@ -3898,8 +3891,7 @@ int FAST_FUNC bb_init_module_24(const char *m_filename, const char *options) exit_status = EXIT_SUCCESS; out: - if (fp) - fclose(fp); + close(fd); free(m_name); return exit_status; -- cgit v1.2.3